Lot of changes here.

1. check_classic_mac_basic.yml — update to latest macOS-latest 2. docker-on-push-tag-or-pr — dependant updates 3. FFTConvolver — fix a compilation warning when the DEBUG flag is turned off 4. Reorganise some source files — e.g. move most of the metadata stuff into a subdirectory 5. Remove unused special-purpose AirPlay 2 RC event handler. 6. Reorganise source files and source code relating to the standard event handler. 7. Check configuration settings a little more carefully to offer more meaningful diagnostics. 8. Add password to AirPlay 2 and reorganise initialisation to set AirPlay 2 flags accordingly. Also, remove redundant airplay_pin. 9. Remove redundant debug facility definitions from common.h 10. Make it possible to omit all the dacp stuff from a build. 11. Make it possible to omit metadata multicast from a build. 12. Add AP2-native metadata by setting bit 50 of features to true. 13. Improve stability when pre-empting an existing play session. 14. Fix a few compiler warnings in the pair_ap library. 15. Ensure that the audio format is known before starting synchronisation. 16. Improve handle_configure to set/clear a new config setting. Doesn’t seem to do anything… 17. Experimentally turn off bit 46 of AirPlay 2 features — seems to stop failing pair-verify attempts.
2026-04-26 10:23:18 +01:00
parent e2bb272d93
commit 11052b7896
56 changed files with 2672 additions and 1947 deletions
@@ -9,9 +9,7 @@ on:
    
 jobs:
  build:
-
-    runs-on: macos-13
-
+    runs-on: macos-latest
    steps:
    - uses: actions/checkout@v6.0.2
    - name: Install Dependencies
@@ -59,7 +59,7 @@ jobs:
          fi
      
      - name: Login to Docker Registry
-        uses: docker/login-action@v3.7.0
+        uses: docker/login-action@v4.1.0
        with:
          registry: ${{ secrets.DOCKER_REGISTRY }}
          username: ${{ secrets.DOCKER_REGISTRY_USER }}
@@ -67,13 +67,13 @@ jobs:
        if: needs.docker-vars.outputs.push_docker_image == 'true'
      
      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3.7.0
+        uses: docker/setup-qemu-action@v4.0.0
      
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v4.0.0
      
      - name: Build and push ${{ matrix.name }}
-        uses: docker/build-push-action@v7.0.0
+        uses: docker/build-push-action@v7.1.0
        env:
          registry_and_name: ${{ secrets.DOCKER_REGISTRY }}/${{ secrets.DOCKER_IMAGE_NAME }}
        with:
@@ -1,7 +1,37 @@
+/*
+ * Convolver Thread Pool. This file is part of Shairport Sync
+ * Copyright (c) Mike Brady 2026
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
 #include "ConvolverThreadPool.h"
 #include "FFTConvolver.h"
 #include "config.h"

+extern "C" void _debug(const char *filename, const int linenumber, int level, const char *format,
+                       ...);
+#define debug(...) _debug(__FILE__, __LINE__, __VA_ARGS__)
+
 ConvolverThreadPool::ConvolverThreadPool()
    : _convolvers(), _threads(), _taskQueue(), _queueMutex(), _condition(), _completionCV(),
      _stop(false), _activeTasks(0) {}
@@ -105,6 +135,16 @@ void ConvolverThreadPool::waitForAll() {
  _completionCV.wait(lock, [this]() { return _taskQueue.empty() && _activeTasks == 0; });
 }

+void ConvolverThreadPool::clearState(size_t convolverId) {
+  // Do the replacement assertion check first, and then wait for all tasks to stop
+  if (convolverId < _convolvers.size()) {
+    waitForAll();
+  } else {
+    debug(1, "assert(convolverId < _convolvers.size()) failed, with convolverId: %u and _convolvers.size(): %u.", convolverId, _convolvers.size());
+  } 
+}
+
+/* this is the old version
 void ConvolverThreadPool::clearState(size_t convolverId) {
  assert(convolverId < _convolvers.size());

@@ -113,6 +153,7 @@ void ConvolverThreadPool::clearState(size_t convolverId) {

  // _convolvers[convolverId]->clearState();
 }
+*/

 void ConvolverThreadPool::clearAllStates() {
  // Make sure no tasks are running before clearing state
@@ -1,4 +1,28 @@
-
+/*
+ * Convolver. This file is part of Shairport Sync
+ * Copyright (c) Mike Brady 2026
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */

 #include "convolver.h"
 #include "ConvolverThreadPool.h"
@@ -22,8 +46,8 @@ void convolver_pool_init(size_t numThreads, size_t numConvolvers) {
  if (!pool.init(numThreads, numConvolvers)) {
    debug(1, "failed to initialize thread pool!");
  } else {
-    debug(1, "thread pool initialized with %u threads and %u convolvers.", numThreads,
-          numConvolvers);
+    debug(1, "thread pool initialized with %u thread%s and %u convolver%s.", numThreads, numThreads == 1 ? "" : "s",
+          numConvolvers, numConvolvers == 1 ? "" : "s");
  }
 }

@@ -11,7 +11,7 @@ homedir = @HOME@
  man_MANS = $(top_srcdir)/man/shairport-sync.1
 # endif

-lib_pair_ap_a_CFLAGS = -Wall -g -DCONFIG_GCRYPT -pthread 
+lib_pair_ap_a_CFLAGS = -Wall -g -DCONFIG_GCRYPT -pthread --include=utilities/debug.h
 lib_tinyhttp_a_CFLAGS = -pthread
 lib_dbus_interface_a_CFLAGS = -pthread
 lib_mpris_interface_a_CFLAGS = -pthread
@@ -27,7 +27,7 @@ noinst_LIBRARIES =

 # See below for the flags for the test client program

-shairport_sync_SOURCES = shairport.c bonjour_strings.c rtsp.c mdns.c common.c rtp.c player.c audio.c loudness.c activity_monitor.c utilities/debug.c utilities/network_utilities.c
+shairport_sync_SOURCES = shairport.c bonjour_strings.c rtsp.c mdns.c common.c rtp.c player.c audio.c loudness.c activity_monitor.c utilities/debug.c utilities/network_utilities.c utilities/rtsp_message_utilities.c

 if BUILD_FOR_DARWIN
  AM_CXXFLAGS = -I/usr/local/include -Wno-multichar -Wall -Wextra -Wno-deprecated-declarations -pthread -DSYSCONFDIR=\"$(sysconfdir)\"
@@ -132,8 +132,20 @@ if USE_DNS_SD
 shairport_sync_SOURCES += mdns_dns_sd.c
 endif

+if USE_METADATA
+shairport_sync_SOURCES += metadata/pc_queue.c metadata/core.c
+endif
+
+if USE_METADATA_PIPE
+shairport_sync_SOURCES += metadata/pipe.c
+endif
+
+if USE_METADATA_MULTICAST
+shairport_sync_SOURCES += metadata/multicast.c
+endif
+
 if USE_METADATA_HUB
-shairport_sync_SOURCES += metadata_hub.c
+shairport_sync_SOURCES += metadata/hub.c
 endif

 if USE_MQTT
@@ -148,7 +160,11 @@ lib_tinyhttp_a_SOURCES =  tinyhttp/chunk.c tinyhttp/header.c tinyhttp/http.c
 endif

 if USE_AIRPLAY_2
-shairport_sync_SOURCES += ap2_buffered_audio_processor.c ap2_event_receiver.c ap2_rc_event_receiver.c ptp-utilities.c utilities/buffered_read.c utilities/structured_buffer.c utilities/mod23.c plists/get_info_response.c
+shairport_sync_SOURCES += ap2_buffered_audio_processor.c ap2_event_receiver.c \
+  ap2_event_message_handler.c ptp-utilities.c \
+  utilities/buffered_read.c utilities/structured_buffer.c utilities/mod23.c \
+  utilities/generate_random_uuid.c utilities/generate_device_uuid.c \
+  plists/get_info_response.c
 shairport_sync_LDADD += lib_pair_ap.a
 lib_pair_ap_a_SOURCES = pair_ap/pair.c pair_ap/pair_fruit.c pair_ap/pair_homekit.c pair_ap/pair-tlv.c
 noinst_LIBRARIES += lib_pair_ap.a
@@ -16,7 +16,7 @@ Shairport Sync does not support AirPlay video or photo streaming.
 * Next Steps and Advanced Topics are [here](ADVANCED%20TOPICS/README.md).
 * Runtime settings are documented [here](scripts/shairport-sync.conf).
 * Build configuration options are detailed in [CONFIGURATION FLAGS.md](CONFIGURATION%20FLAGS.md).
-* The `man` page, detailing command line options, is [here](https://htmlpreview.github.io/?https://github.com/mikebrady/shairport-sync/blob/development/man/shairport-sync.html).
+* The `man` page, detailing command line options, is [here](https://raw.githack.com/mikebrady/shairport-sync/development/man/shairport-sync.1.xml).
 * Some advanced topics and developed in [ADVANCED TOPICS](https://github.com/mikebrady/shairport-sync/tree/master/ADVANCED%20TOPICS).

 # Features
@@ -1,7 +1,49 @@
+Version 5.0.3-dev-4-g07ca1891
+==
+**Bug Fix**
+* Make code using `getifaddrs()` uncancellable to prevent a mysterious `Unexpected error 9 on netlink descriptor` error. Thanks to [microfx](https://github.com/microfx) for reporting the [issue](https://github.com/mikebrady/shairport-sync/issues/2184).
+
+Version 5.0.3-dev
+==
+**Small Changes**
+* Add warnings if string or boolean configuration parameters were present but not strings.
+* Improve behaviour when there is a large timing uncertainty/granularity and a large audio buffer. e.g. on some virtual machines.
+* Make the SoxR delay checker thread behave better when being cancelled.
+* Remove some debug messages, quieten some others, add a few.
+
+Version 5.0.1+-38-gf784e463
+==
+**Build Update**
+* The Apple ALAC Decoder can no longer be included in an AirPlay 2 build. The reason is that FFmpeg -- used instead -- deals comprehensively with ALAC, AAC, multichannel, mixdown and rate transcoding and is well maintained.
+
+  The Apple ALAC Decoder is known to have security issues and is no longer maintained. This update prevents it from being included in Shairport Sync for AirPlay 2.
+
+Version 5.0.1+-36-g6729802d
+==
+**Update**
+* The Shairport Sync `systemd` service file has been updated as follows:
+  * It uses POSIX shell parameter expansion functionality to prevent adding leading space in option values.
+  * It adds `nqptp.service` to the `After` and `Requires` options when building for Airplay 2.
+  
+  Many thanks to [mikelei8291](https://github.com/mikelei8291) for the [PR](https://github.com/mikebrady/shairport-sync/pull/2174).
+
+Version 5.0.1+-32-g20a87fef
+==
+**Build Bugfix**
+* Fix a bug at the `.configure...` stage of a build of Classic Shairport Sync whereby the UUID library was incorrectly required if the FFmpeg library was being used. (The wording on a few associated warning messages was also fixed.) Thanks to [phexian](https://github.com/phexian) for the [report](https://github.com/mikebrady/shairport-sync/issues/2177).
+  
+**Dependabot Update**
+* A Dependabot update to a building tool was added.
+
+Version 5.0.1+-23-g7fb3506e
+==
+**Documentation Update**
+* Fixed dead link to the online [`man`](https://raw.githack.com/mikebrady/shairport-sync/development/man/shairport-sync.1.xml) page. Thanks to [CornelisJ](https://github.com/CornelisJ) for the [report](https://github.com/mikebrady/shairport-sync/issues/2158).
+
 Version 5.0.1+-13-ga14517d7
 ==
 **Change**
-* When built for AirPlay 2, add pw=true to the Bonjour raop properties if the classic AirPlay password is set. This might help with Owntone compatibility.
+* When built for AirPlay 2, add `pw=true` to the Bonjour raop properties if the classic AirPlay password is set. This might help with Owntone compatibility.

 Version 5.0.1+-11-g07546c35
 ==
@@ -40,7 +40,10 @@

 #include "activity_monitor.h"
 #include "common.h"
-#include "rtsp.h"
+
+#ifdef CONFIG_METADATA
+#include "metadata/core.h"
+#endif

 #ifdef CONFIG_DBUS_INTERFACE
 #include "dbus-service.h"
@@ -128,7 +131,7 @@ void activity_monitor_signify_activity(int active) {
    pthread_mutex_unlock(&activity_monitor_mutex);
  }
  // lock the mutex again to send a signal
-  pthread_cleanup_debug_mutex_lock(&activity_monitor_mutex, 10000, 1);
+  pthread_cleanup_debug_mutex_lock(&activity_monitor_mutex, 10000, 4);
  pthread_cond_signal(&activity_monitor_cv);
  pthread_cleanup_pop(1); // release the mutex
 }
@@ -235,6 +235,7 @@ void *rtp_buffered_audio_processor(void *arg) {
      uint16_t data_len;
      // here we read from the buffer that our thread has been reading

+      // debug(1,"read a block");
      size_t bytes_remaining_in_buffer;
      nread =
          read_sized_block(buffered_audio, &data_len, sizeof(data_len), &bytes_remaining_in_buffer);
@@ -249,6 +250,7 @@ void *rtp_buffered_audio_processor(void *arg) {
        // get the block itself
        // debug(1,"buffered audio packet of size %u detected.", data_len - 2);
        nread = read_sized_block(buffered_audio, packet, data_len - 2, &bytes_remaining_in_buffer);
+        // debug(1,"block read");

        // diagnostic
        if ((conn->ap2_audio_buffer_minimum_size < 0) ||
@@ -442,7 +444,7 @@ void *rtp_buffered_audio_processor(void *arg) {
      // to decode it and pass it to the player
      if (new_audio_block_needed == 0) {
        // is there space in the player thread's buffer system?
-        size_t player_buffer_occupancy = get_audio_buffer_occupancy(conn);
+        // size_t player_buffer_occupancy = get_audio_buffer_occupancy(conn);
        // debug(1,"player buffer size and occupancy: %u and %u", player_buffer_size,
        // player_buffer_occupancy);

@@ -451,17 +453,41 @@ void *rtp_buffered_audio_processor(void *arg) {
        // and send it to the player. Otherwise, keep the block and sleep for a while.

        // calculate if there is room in the decoded audio buffer...
-        int audio_decoded_buffer_below_desired_length = ((1.0 * player_buffer_occupancy * conn->frames_per_packet) / conn->input_rate) <= config.audio_decoded_buffer_desired_length;
+        
+        // debug(1, "frames buffered: %f seconds, desired length: %f seconds.", (1.0 * player_buffer_occupancy * conn->frames_per_packet) / conn->input_rate, config.audio_decoded_buffer_desired_length);
+        
+        // int audio_decoded_buffer_below_desired_length = ((1.0 * player_buffer_occupancy * conn->frames_per_packet) / conn->input_rate) <= config.audio_decoded_buffer_desired_length;
        uint64_t buffer_should_be_time;
        
        int have_valid_time = (frame_to_local_time(timestamp, &buffer_should_be_time, conn) == 0);
        
        // calculate the lead time to make sure it's not too early...
        int64_t lead_time = buffer_should_be_time - get_absolute_time_in_ns();
-                
-        if ((play_enabled != 0) && (have_valid_time != 0) &&
-            (audio_decoded_buffer_below_desired_length != 0) &&
-            (lead_time * 1E-9 < (config.audio_decoded_buffer_desired_length + 0.1))) {
+        
+        
+        // debug(1,"play_enabled: %d, have_valid_time: %d, audio_decoded_buffer_below_desired_length: %d, lead_time * 1E-9: %f, (config.audio_decoded_buffer_desired_length + 0.1): %f, player_buffer_occupancy: %zu",
+        //  play_enabled, have_valid_time, audio_decoded_buffer_below_desired_length, lead_time * 1E-9, (config.audio_decoded_buffer_desired_length + 0.1), player_buffer_occupancy
+        // );
+             
+        // A slight problem here is that counting the number of buffers may not be sufficient,
+        // because the actual device may be
+        // taking data in large quantities at a single time.
+
+        // So we just have to ensure that there
+        // is enough of a lead time maintained for sufficient audio to be available to prevent
+        // the device from under-running.
+        
+        // If means that the Shairport Sync player might riun out of audio occasionally, but
+        // as long as the device has enough in its buffer, everything is fine.
+        
+        // But it also means that Shairport Sync's buffers must be sufficient to hold all the
+        // entire lead-time's amount of audio in case the device has a zero-sized buffer.
+            
+        if ((play_enabled != 0) && (have_valid_time != 0)
+//            (audio_decoded_buffer_below_desired_length != 0) &&
+            && (lead_time * 1E-9 < (config.audio_decoded_buffer_desired_length + 0.1))
+//            && (audio_decoded_buffer_below_desired_length != 0)
+            ) {
            
            very_early_packets_signalled = 0; //reset very early packet warning signaller
          
@@ -639,8 +665,7 @@ void *rtp_buffered_audio_processor(void *arg) {
            debug(1, "incoming frame suddenly (?) has a lead time of %f seconds, with a desired decoded buffer length of %f.", 1.0 * lead_time * 1E-9, config.audio_decoded_buffer_desired_length);
            very_early_packets_signalled = 1;
          }
-        
-          usleep(20000); // wait for a while
+          usleep(((1000000 * conn->frames_per_packet) / conn->input_rate) * 2); // wait for approximately the length of two packets
        }
      }
    }
@@ -0,0 +1,140 @@
+/*
+ * AirPlay 2 Event Port Message Handler. This file is part of Shairport Sync
+ * Copyright (c) Mike Brady 2025
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include "ap2_event_message_handler.h"
+#include "common.h"
+#include "rtsp.h"
+#include "utilities/structured_buffer.h"
+#include "utilities/generate_random_uuid.h"
+
+
+void decodeAndLogPlist(plist_t plist_to_log) { 
+  if (plist_to_log != NULL) {
+    char *plist_as_string = plist_as_xml_text(plist_to_log);
+    if (plist_as_string != NULL) {
+      debug(3, "--\n%s\n--\n", plist_as_string);
+      free(plist_as_string);
+    }
+  }
+}
+
+// will return -1 if there is an error or port is not open, 0 if the port was closed and a positive
+// number if okay
+ssize_t ap2_event_port_send_message(rtsp_conn_info *conn, char *data, size_t data_length) {
+  ssize_t result = -1; // assume a problem
+  debug_mutex_lock(&conn->event_sender_mutex, 1000000, 4);
+  pthread_cleanup_push(mutex_unlock, &conn->event_sender_mutex);
+  if (conn->event_channel_fd != 0) {
+    result = write_encrypted(conn->event_channel_fd, &conn->ap2_pairing_context.event_cipher_bundle,
+                             data, data_length);
+    if ((result != -1) && ((size_t)result == data_length)) {
+      debug(3, "Connection %d: Packet of %zu bytes successfully written on the Event Port.",
+            conn->connection_number, result);
+      uint8_t packet[4096];
+      result =
+          read_encrypted(conn->event_channel_fd, &conn->ap2_pairing_context.event_cipher_bundle,
+                         packet, sizeof(packet));
+      debug(3, "Connection %d: Packet of %zu bytes successfully read on the Event Port.",
+            conn->connection_number, result);
+      if (result > 0) {
+        packet[result] = '\0';
+        debug(3, "Connection %d: Packet Received on Event Port with contents: \n--\n%s\n--\n",
+              conn->connection_number, packet);
+      } else {
+        debug(2, "Connection %d: Event Port connection closed by client", conn->connection_number);
+      }
+    } else {
+      result = -1; // this covers a situation where the result is positive but not the same as the
+                   // data_length
+    }
+  } else {
+    debug(1, "Connection %d: attempt to send a command to the event port over a closed socket",
+          conn->connection_number);
+  }
+  pthread_cleanup_pop(1); // unlock the mutex
+  return result;
+}
+
+ssize_t ap2_event_port_post_command(rtsp_conn_info *conn, plist_t command) {
+  ssize_t result = 0;
+  decodeAndLogPlist(command);  
+  structured_buffer *sbuf = sbuf_new(4096);
+  if (sbuf != NULL) {
+    pthread_cleanup_push(sbuf_cleanup, sbuf);
+    char *plistString = NULL;
+    uint32_t plistStringLength = 0;
+    
+    plist_to_bin(command, &plistString, &plistStringLength);
+    if (plistString != NULL) {
+      sbuf_printf(sbuf, "POST /command RTSP/1.0\r\nContent-Length: %u\r\n", plistStringLength);
+      sbuf_printf(sbuf, "Content-Type: application/x-apple-binary-plist\r\n\r\n");
+      sbuf_append(sbuf, plistString, plistStringLength);
+      free(plistString); // should be plist_to_bin_free, but it's not defined in older
+                         // libraries
+      char *b = 0;
+      size_t l = 0;
+      sbuf_buf_and_length(sbuf, &b, &l);
+      result = ap2_event_port_send_message(conn, b, l);
+      debug(3, "Connection %d: POST /command sent on the event port. Result is %zd.",
+            conn->connection_number, result);
+      sbuf_clear(sbuf);
+    }
+    pthread_cleanup_pop(1); // delete the structured buffer
+  }
+  return result;  
+}
+
+ssize_t ap2_event_send_update_info(rtsp_conn_info *conn) {
+  // sends the updateInfo plist on the event port
+  ssize_t result = -1;
+  plist_t value_plist = generateInfoPlist(conn);
+  if (value_plist != NULL) {
+    void *txtData = NULL;
+    size_t txtDataLength = 0;
+    generateTxtDataValueInfo(conn, &txtData, &txtDataLength);
+    plist_dict_set_item(value_plist, "txtAirPlay", plist_new_data(txtData, txtDataLength));
+    free(txtData);
+    plist_t update_info_plist = plist_new_dict();
+    if (update_info_plist != NULL) {
+      plist_dict_set_item(update_info_plist, "type", plist_new_string("updateInfo"));
+      plist_dict_set_item(update_info_plist, "value", value_plist);
+      
+      char *plist_as_string = plist_as_xml_text(update_info_plist);
+      if (plist_as_string != NULL) {
+        debug(3, "update_info_plist is:\n--\n\"%s\"\n--\n", plist_as_string);
+        free(plist_as_string);
+      }
+      
+      result = ap2_event_port_post_command(conn, update_info_plist);           
+      plist_free(update_info_plist);
+    } else {
+      debug(1, "Could not build an updateInfo plist");
+    }
+  } else {
+    debug(1, "Could not build an updateInfo value plist");
+  }
+  return result;
+}
@@ -0,0 +1,14 @@
+#ifndef _AP2_EVENT_COMMAND_SENDER_H
+#define _AP2_EVENT_COMMAND_SENDER_H
+
+#include <stddef.h>
+#include <sys/types.h>
+#include "player.h"
+
+ssize_t ap2_event_send_unit_volume_notification(rtsp_conn_info *conn, double volume);
+ssize_t ap2_event_send_modern_media_remote_command(rtsp_conn_info *conn, unsigned int command_number);
+ssize_t ap2_event_send_update_info(rtsp_conn_info *conn);
+
+ssize_t ap2_event_send_dev_mule();
+
+#endif // _AP2_EVENT_COMMAND_SENDER_H
@@ -1,6 +1,6 @@
 /*
 * Apple AirPlay 2 Event Receiver. This file is part of Shairport Sync.
- * Copyright (c) Mike Brady 2014--2025
+ * Copyright (c) Mike Brady 2014--2026
 * All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person
@@ -25,23 +25,27 @@
 */

 #include "ap2_event_receiver.h"
-#include "bonjour_strings.h"
+#include "ap2_event_message_handler.h"
 #include "common.h"
 #include "player.h"
-#include "ptp-utilities.h"
-#include "rtsp.h"
 #include "utilities/network_utilities.h"
-#include "utilities/structured_buffer.h"
+
+#ifdef CONFIG_METADATA
+#include "metadata/core.h"
+#endif

 void ap2_event_receiver_cleanup_handler(void *arg) {
  rtsp_conn_info *conn = (rtsp_conn_info *)arg;
  // debug(1, "Connection %d: AP2 Event Receiver Cleanup start.", conn->connection_number);
-  // only update these things if you're (still) the principal conn
-
 #ifdef CONFIG_METADATA
  // this is here to ensure it's only performed once during a teardown of a ptp stream
  send_ssnc_metadata('disc', conn->client_ip_string, strlen(conn->client_ip_string), 1);
 #endif
+  debug_mutex_lock(&conn->event_sender_mutex, 1000000, 4);
+  pthread_cleanup_push(mutex_unlock, &conn->event_sender_mutex);
+  close(conn->event_channel_fd);
+  conn->event_channel_fd = 0;
+  pthread_cleanup_pop(1); // unlock the mutex

  if (conn->airplay_gid != NULL) {
    free(conn->airplay_gid);
@@ -52,161 +56,43 @@ void ap2_event_receiver_cleanup_handler(void *arg) {
    free(conn->dacp_active_remote);
    conn->dacp_active_remote = NULL;
  }
-  if (conn->ap2_client_name) {
-    free(conn->ap2_client_name);
-    conn->ap2_client_name = NULL;
-  }
-  /*
-  pthread_rwlock_wrlock(&principal_conn_lock); // don't let the principal_conn be changed
-  pthread_cleanup_push(rwlock_unlock, (void *)&principal_conn_lock);
-  if (principal_conn)
-    debug(1, "principal_conn: %d.", principal_conn->connection_number);
-  else
-    debug(1, "principal_conn: is NULL.");
-  if (principal_conn == conn) {
-    config.airplay_statusflags &= (0xffffffff - (1 << 11)); // DeviceSupportsRelay
-    build_bonjour_strings(conn);
-    debug(1, "Connection %d: SETUP mdns_update on %s.", conn->connection_number,
-          get_category_string(conn->airplay_stream_category));
-    mdns_update(NULL, secondary_txt_records);
-    principal_conn = NULL;
-  }
-  pthread_cleanup_pop(1); // release the principal_conn lock
-  */
  debug(2, "Connection %d: AP2 Event Receiver Cleanup is complete.", conn->connection_number);
 }

 void *ap2_event_receiver(void *arg) {
-  //  #include <syscall.h>
-  //  debug(1, "rtp_event_receiver PID %d", syscall(SYS_gettid));
  rtsp_conn_info *conn = (rtsp_conn_info *)arg;
  debug(2, "Connection %d: AP2 Event Receiver started", conn->connection_number);
-  structured_buffer *sbuf = sbuf_new(4096);
-  if (sbuf != NULL) {
-    pthread_cleanup_push(sbuf_cleanup, sbuf);
+  SOCKADDR remote_addr;
+  memset(&remote_addr, 0, sizeof(remote_addr));
+  socklen_t addr_size = sizeof(remote_addr);

-    /*
-    // only update these things if you're (still) the principal conn
-    pthread_rwlock_wrlock(&principal_conn_lock); // don't let the principal_conn be changed
-    pthread_cleanup_push(rwlock_unlock, (void *)&principal_conn_lock);
-    if (principal_conn == conn) {
-      config.airplay_statusflags |= 1 << 11; // DeviceSupportsRelay
-      // config.airplay_statusflags |= 1 << 17; // ReceiverSessionIsActive
-      build_bonjour_strings(conn);
-      debug(2, "Connection %d: SETUP mdns_update on %s.", conn->connection_number,
-            get_category_string(conn->airplay_stream_category));
-      mdns_update(NULL, secondary_txt_records);
-    }
-    pthread_cleanup_pop(1); // release the principal_conn lock
-    */
-    pthread_cleanup_push(ap2_event_receiver_cleanup_handler, arg);
-
-    // listen(conn->event_socket, 5); // this is now done in the handle_setup_2 code
-
-    uint8_t packet[4096];
-    ssize_t nread;
-    SOCKADDR remote_addr;
-    memset(&remote_addr, 0, sizeof(remote_addr));
-    socklen_t addr_size = sizeof(remote_addr);
-
-    int fd = eintr_checked_accept(conn->event_socket, (struct sockaddr *)&remote_addr, &addr_size);
+  debug_mutex_lock(&conn->event_sender_mutex, 1000000, 4);
+  pthread_cleanup_push(mutex_unlock, &conn->event_sender_mutex);
+  conn->event_channel_fd = eintr_checked_accept(conn->event_socket, (struct sockaddr *)&remote_addr, &addr_size);
+  pthread_cleanup_pop(1); // unlock the mutex
+  if (conn->event_channel_fd > 0) {
    debug(2,
          "Connection %d: ap2_event_receiver accepted a connection on socket %d and moved to a new "
          "socket %d.",
-          conn->connection_number, conn->event_socket, fd);
-    intptr_t pfd = fd;
-    pthread_cleanup_push(socket_cleanup, (void *)pfd);
-    int finished = 0;
-    do {
-
-      plist_t value_plist = generateInfoPlist(conn);
-      if (value_plist != NULL) {
-        void *txtData = NULL;
-        size_t txtDataLength = 0;
-        generateTxtDataValueInfo(conn, &txtData, &txtDataLength);
-        plist_dict_set_item(value_plist, "txtAirPlay", plist_new_data(txtData, txtDataLength));
-        free(txtData);
-        plist_t update_info_plist = plist_new_dict();
-        if (update_info_plist != NULL) {
-          plist_dict_set_item(update_info_plist, "type", plist_new_string("updateInfo"));
-          plist_dict_set_item(update_info_plist, "value", value_plist);
-          char *plistString = NULL;
-          uint32_t plistStringLength = 0;
-          plist_to_bin(update_info_plist, &plistString, &plistStringLength);
-          if (plistString != NULL) {
-            char *plist_as_string = plist_as_xml_text(update_info_plist);
-            if (plist_as_string != NULL) {
-              debug(3, "Plist is: \"%s\".", plist_as_string);
-              free(plist_as_string);
-            }
-            sbuf_printf(sbuf, "POST /command RTSP/1.0\r\nContent-Length: %u\r\n",
-                        plistStringLength);
-            sbuf_printf(sbuf, "Content-Type: application/x-apple-binary-plist\r\n\r\n");
-            sbuf_append(sbuf, plistString, plistStringLength);
-
-            free(plistString); // should be plist_to_bin_free, but it's not defined in older
-                               // libraries
-            char *b = 0;
-            size_t l = 0;
-            sbuf_buf_and_length(sbuf, &b, &l);
-            ssize_t wres =
-                write_encrypted(fd, &conn->ap2_pairing_context.event_cipher_bundle, b, l);
-            if ((wres == -1) || ((size_t)wres != l))
-              debug(1, "Encrypted write error");
-
-            sbuf_clear(sbuf);
-          } else {
-            debug(1, "plist string not created!");
-          }
-          plist_free(update_info_plist);
-        } else {
-          debug(1, "Could not build an updateInfo plist");
-        }
-        // plist_free(value_plist);
-      } else {
-        debug(1, "Could not build an value plist");
-      }
-
-      while (finished == 0) {
-        nread = read_encrypted(fd, &conn->ap2_pairing_context.event_cipher_bundle, packet,
-                               sizeof(packet));
-
-        // nread = recv(fd, packet, sizeof(packet), 0);
-
-        if (nread < 0) {
-          char errorstring[1024];
-          strerror_r(errno, (char *)errorstring, sizeof(errorstring));
-          debug(1,
-                "Connection %d: error in ap2_event_receiver %d: \"%s\". Could not recv a packet.",
-                conn->connection_number, errno, errorstring);
-          // if ((config.diagnostic_drop_packet_fraction == 0.0) ||
-          //     (drand48() > config.diagnostic_drop_packet_fraction)) {
-        } else if (nread > 0) {
-
-          // ssize_t plen = nread;
-          packet[nread] = '\0';
-          debug(3, "Connection %d: Packet Received on Event Port with contents: \"%s\".",
-                conn->connection_number, packet);
-        } else {
-          debug(2, "Connection %d: Event Port connection closed by client",
-                conn->connection_number);
-          finished = 1;
-        }
-      }
-
-    } while (finished == 0);
-
+          conn->connection_number, conn->event_socket, conn->event_channel_fd);
+    pthread_cleanup_push(ap2_event_receiver_cleanup_handler, arg);
+        
+    ap2_event_send_update_info(conn);
+      
+  
+    while (1) {
+      usleep(1000000);
+    };
+  
    debug(3, "Connection %d: AP2 Event Receiver RTP thread starting \"normal\" exit.",
          conn->connection_number);
-    pthread_cleanup_pop(1); // close the socket
-
    pthread_cleanup_pop(1); // do the cleanup
-    pthread_cleanup_pop(1); // delete the structured buffer
-    debug(2, "Connection %d: AP2 Event Receiver RTP thread \"normal\" exit.",
-          conn->connection_number);
  } else {
-    debug(1, "Could not allocate a structured buffer!");
+    debug(1, "Connection %d: could not accept an event socket", conn->connection_number);
+    conn->event_channel_fd = 0;
  }
+  debug(2, "Connection %d: AP2 Event Receiver RTP thread \"normal\" exit.",
+        conn->connection_number);
  conn->ap2_event_receiver_exited = 1;
  pthread_exit(NULL);
 }
@@ -1,161 +0,0 @@
-/*
- * Apple AirPlay 2 Remote Control (RC) Event Receiver. This file is part of Shairport Sync.
- * Copyright (c) Mike Brady 2014--2025
- * All rights reserved.
- *
- * Permission is hereby granted, free of charge, to any person
- * obtaining a copy of this software and associated documentation
- * files (the "Software"), to deal in the Software without
- * restriction, including without limitation the rights to use,
- * copy, modify, merge, publish, distribute, sublicense, and/or
- * sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
- * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
- * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
- * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
- * OTHER DEALINGS IN THE SOFTWARE.
- */
-
-#include "ap2_rc_event_receiver.h"
-#include "common.h"
-#include "player.h"
-#include "rtsp.h"
-#include "utilities/network_utilities.h"
-#include "utilities/structured_buffer.h"
-
-void ap2_rc_event_receiver_cleanup_handler(void *arg) {
-  rtsp_conn_info *conn = (rtsp_conn_info *)arg;
-  debug(2, "Connection %d: AP2 Event Receiver Cleanup.", conn->connection_number);
-}
-
-void *ap2_rc_event_receiver(void *arg) {
-  //  #include <syscall.h>
-  //  debug(1, "rtp_event_receiver PID %d", syscall(SYS_gettid));
-  rtsp_conn_info *conn = (rtsp_conn_info *)arg;
-  if (conn->airplay_stream_category == remote_control_stream)
-    debug(2, "Connection %d (RC): AP2 RC Event Receiver started", conn->connection_number);
-  else
-    debug(2, "Connection %d: AP2 RC Event Receiver started", conn->connection_number);
-
-  structured_buffer *sbuf = sbuf_new(4096);
-  if (sbuf != NULL) {
-    pthread_cleanup_push(sbuf_cleanup, sbuf);
-
-    pthread_cleanup_push(ap2_rc_event_receiver_cleanup_handler, arg);
-
-    // listen(conn->event_socket, 5); // this is now done in the handle_setup_2 code
-
-    uint8_t packet[4096];
-    ssize_t nread;
-    SOCKADDR remote_addr;
-    memset(&remote_addr, 0, sizeof(remote_addr));
-    socklen_t addr_size = sizeof(remote_addr);
-
-    int fd = eintr_checked_accept(conn->event_socket, (struct sockaddr *)&remote_addr, &addr_size);
-    debug(2,
-          "Connection %d: ap2_rc_event_receiver accepted a connection on socket %d and moved to a "
-          "new "
-          "socket %d.",
-          conn->connection_number, conn->event_socket, fd);
-    intptr_t pfd = fd;
-    pthread_cleanup_push(socket_cleanup, (void *)pfd);
-    int finished = 0;
-    do {
-
-      plist_t value_plist = generateInfoPlist(conn);
-      if (value_plist != NULL) {
-        void *txtData = NULL;
-        size_t txtDataLength = 0;
-        generateTxtDataValueInfo(conn, &txtData, &txtDataLength);
-        plist_dict_set_item(value_plist, "txtAirPlay", plist_new_data(txtData, txtDataLength));
-        free(txtData);
-        plist_t update_info_plist = plist_new_dict();
-        if (update_info_plist != NULL) {
-          plist_dict_set_item(update_info_plist, "type", plist_new_string("updateInfo"));
-          plist_dict_set_item(update_info_plist, "value", value_plist);
-          char *plistString = NULL;
-          uint32_t plistStringLength = 0;
-          plist_to_bin(update_info_plist, &plistString, &plistStringLength);
-          if (plistString != NULL) {
-            char *plist_as_string = plist_as_xml_text(update_info_plist);
-            if (plist_as_string != NULL) {
-              debug(3, "Plist is: \"%s\".", plist_as_string);
-              free(plist_as_string);
-            }
-            sbuf_printf(sbuf, "POST /command RTSP/1.0\r\nContent-Length: %u\r\n",
-                        plistStringLength);
-            sbuf_printf(sbuf, "Content-Type: application/x-apple-binary-plist\r\n\r\n");
-            sbuf_append(sbuf, plistString, plistStringLength);
-
-            free(plistString); // should be plist_to_bin_free, but it's not defined in older
-                               // libraries
-            char *b = 0;
-            size_t l = 0;
-            sbuf_buf_and_length(sbuf, &b, &l);
-            ssize_t wres =
-                write_encrypted(fd, &conn->ap2_pairing_context.event_cipher_bundle, b, l);
-            if ((wres == -1) || ((size_t)wres != l))
-              debug(1, "Encrypted write error");
-
-            sbuf_clear(sbuf);
-          } else {
-            debug(1, "plist string not created!");
-          }
-          plist_free(update_info_plist);
-        } else {
-          debug(1, "Could not build an updateInfo plist");
-        }
-        // plist_free(value_plist);
-      } else {
-        debug(1, "Could not build an value plist");
-      }
-
-      while (finished == 0) {
-        nread = read_encrypted(fd, &conn->ap2_pairing_context.event_cipher_bundle, packet,
-                               sizeof(packet));
-
-        // nread = recv(fd, packet, sizeof(packet), 0);
-
-        if (nread < 0) {
-          char errorstring[1024];
-          strerror_r(errno, (char *)errorstring, sizeof(errorstring));
-          debug(
-              1,
-              "Connection %d: error in ap2_rc_event_receiver %d: \"%s\". Could not recv a packet.",
-              conn->connection_number, errno, errorstring);
-          // if ((config.diagnostic_drop_packet_fraction == 0.0) ||
-          //     (drand48() > config.diagnostic_drop_packet_fraction)) {
-        } else if (nread > 0) {
-
-          // ssize_t plen = nread;
-          packet[nread] = '\0';
-          debug(2,
-                "Connection %d: ap2_rc_event_receiver Packet Received on Event Port with contents: "
-                "\"%s\".",
-                conn->connection_number, packet);
-        } else {
-          debug(2, "Connection %d: ap2_rc_event_receiver Event Port connection closed by client",
-                conn->connection_number);
-          finished = 1;
-        }
-      }
-
-    } while (finished == 0);
-    pthread_cleanup_pop(1); // close the socket
-    pthread_cleanup_pop(1); // do the cleanup
-    pthread_cleanup_pop(1); // delete the structured buffer
-    debug(2, "Connection %d: AP2 ap2_rc_event_receiver  \"normal\" exit.", conn->connection_number);
-  } else {
-    debug(1, "Could not allocate a structured buffer!");
-  }
-  conn->ap2_event_receiver_exited = 1;
-  pthread_exit(NULL);
-}
@@ -1,8 +0,0 @@
-// RC means Remote Control
-
-#ifndef _AP2_RC_EVENT_RECEIVER_H
-#define _AP2_RC_EVENT_RECEIVER_H
-
-void *ap2_rc_event_receiver(void *arg);
-
-#endif // _AP2_RC_EVENT_RECEIVER_H
@@ -985,7 +985,7 @@ int32_t search_for_suitable_configuration(unsigned int channels, unsigned int ra
        }
 #ifdef CONFIG_FFMPEG
        if (local_format == SPS_FORMAT_UNKNOWN) {
-          debug(3, "check for an next highest rate above %u with %u channels.", rate,
+          debug(3, "check for the next highest rate above %u with %u channels.", rate,
                local_channels);
          unsigned int rate_pointer = 0;
          while ((rate_pointer < sizeof(rates) / sizeof(unsigned int)) &&
@@ -1003,7 +1003,7 @@ int32_t search_for_suitable_configuration(unsigned int channels, unsigned int ra

        if (local_format == SPS_FORMAT_UNKNOWN) {
          int rate_pointer = (int)(sizeof(rates) / sizeof(unsigned int) - 1);
-          debug(3, "check for an next lowest rate below %u with %u channels.", rate,
+          debug(3, "check for the next lowest rate below %u with %u channels.", rate,
                local_channels);
          while ((rate_pointer >= 0) && (local_format == SPS_FORMAT_UNKNOWN)) {
            local_rate = rates[rate_pointer];
@@ -306,7 +306,7 @@ static int get_permissible_configuration_settings() {
              debug(3, "\"%s\" can handle %u channels.", alsa_out_dev, c);
            } else {
              // the device can't handle this number of channels
-              debug(3, "\"%s\" can not handle %u channels.", alsa_out_dev, c);
+              debug(4, "\"%s\" can not handle %u channels.", alsa_out_dev, c);
              config.channel_set &=
                  ~(1 << c); // the alsa device can't accommodate this number of channels
            }
@@ -332,7 +332,7 @@ static int get_permissible_configuration_settings() {
              debug(3, "\"%s\" can handle a rate of %u fps.", alsa_out_dev,
                    sps_rate_actual_rate(r));
            } else {
-              debug(3, "\"%s\" can not handle a rate of %u fps.", alsa_out_dev,
+              debug(4, "\"%s\" can not handle a rate of %u fps.", alsa_out_dev,
                    sps_rate_actual_rate(r));
              config.rate_set &= ~(1 << r); // the alsa device doesn't do this rate
            }
@@ -357,7 +357,7 @@ static int get_permissible_configuration_settings() {
              debug(3, "\"%s\" can handle the %s format.", alsa_out_dev,
                    sps_format_description_string(f));
            } else {
-              debug(3, "\"%s\" can not handle the %s format.", alsa_out_dev,
+              debug(4, "\"%s\" can not handle the %s format.", alsa_out_dev,
                    sps_format_description_string(f));
              config.format_set &= ~(1 << f); // the alsa device doesn't do this format
            }
@@ -2177,14 +2177,14 @@ static void flush(void) {
 }

 static void stop(void) {
-  pthread_cleanup_debug_mutex_lock(&alsa_mutex, 10000, 1);
+  pthread_cleanup_debug_mutex_lock(&alsa_mutex, 10000, 4);
  if (alsa_backend_state != abm_disconnected) { // must be playing or connected...
    if (config.keep_dac_busy == 0) {
      do_close();
    }
  } else
    debug(3, "alsa: stop() -- called on a disconnected alsa backend");
-  debug_mutex_unlock(&alsa_mutex, 3);
+  debug_mutex_unlock(&alsa_mutex, 4);
  pthread_cleanup_pop(0); // release the mutex
 }

@@ -2252,7 +2252,7 @@ static void *alsa_buffer_monitor_thread_code(__attribute__((unused)) void *arg)
  //  #include <syscall.h>
  //  debug(1, "alsa_buffer_monitor_thread_code PID %d", syscall(SYS_gettid));
  // Wait until the output configuration has been set by the main program
-  debug(2, "alsa: alsa_buffer_monitor_thread_code started.");
+  debug(1, "alsa: alsa_buffer_monitor_thread_code started.");
  int frame_count = 0;
  int error_count = 0;
  int error_detected = 0;
@@ -149,7 +149,7 @@ void build_bonjour_strings(__attribute((unused)) rtsp_conn_info *conn) {
  entry_number = 0;

  secondary_txt_records[entry_number++] = "acl=0";
-  secondary_txt_records[entry_number++] = "btaddr=00:00:00:00:00:00";
+  // secondary_txt_records[entry_number++] = "btaddr=00:00:00:00:00:00";
  secondary_txt_records[entry_number++] =
      bnprintf(deviceIdString, sizeof(deviceIdString), "deviceid=%s", config.airplay_device_id);
  secondary_txt_records[entry_number++] =
@@ -1041,32 +1041,49 @@ uint8_t *rsa_apply(uint8_t *input, int inlen, int *outlen, int mode) {
 #endif

 int config_lookup_non_empty_string(const config_t *cfg, const char *path, const char **value) {
-  int response = config_lookup_string(cfg, path, value);
-  if (response == CONFIG_TRUE) {
-    if ((value != NULL) && ((*value == NULL) || (*value[0] == 0))) {
-      warn("The \"%s\" parameter is an empty string and has been ignored.", path);
-      response = CONFIG_FALSE;
+  int response = CONFIG_FALSE;
+  config_setting_t *s = config_lookup(cfg, path);
+  if (s != NULL) {
+    // the setting exists, but might not be a string
+    if (config_setting_type(s) == CONFIG_TYPE_STRING) {
+      if (value != NULL) {
+        *value = config_setting_get_string(s);
+        response = CONFIG_TRUE;
+        // the string might be empty...
+        if ((*value == NULL) || (*value[0] == 0)) {
+          warn("The \"%s\" parameter is an empty string and has been ignored.", path);
+          response = CONFIG_FALSE;
+        }
+      }
+    } else {
+      warn("the \"%s\" parameter is not a string, as required, and has been ignored.", path);
    }
  }
  return response;
 }

-int config_set_lookup_bool(config_t *cfg, char *where, int *dst) {
-  const char *str = 0;
-  if (config_lookup_string(cfg, where, &str)) {
-    if (strcasecmp(str, "no") == 0) {
-      (*dst) = 0;
-      return 1;
-    } else if (strcasecmp(str, "yes") == 0) {
-      (*dst) = 1;
-      return 1;
+int config_set_lookup_bool(config_t *cfg, const char *where, int *dst) {
+  const char *str = NULL;
+  int response = CONFIG_FALSE;
+  config_setting_t *s = config_lookup(cfg, where);
+  if (s != NULL) { 
+    if (config_setting_type(s) == CONFIG_TYPE_STRING) {
+      str = config_setting_get_string(s);
+      if (strcasecmp(str, "no") == 0) {
+        (*dst) = 0;
+        response = CONFIG_TRUE;
+      } else if (strcasecmp(str, "yes") == 0) {
+        (*dst) = 1;
+        response = CONFIG_TRUE;
+      } else {
+        die("invalid boolean parameter \"%s\" option choice \"%s\". It should be \"yes\" or \"no\"", where, str);
+        return 0;
+      }
    } else {
-      die("Invalid %s option choice \"%s\". It should be \"yes\" or \"no\"", where, str);
-      return 0;
+        warn("the \"%s\" parameter is not a string with a value of \"yes\" or \"no\", as required, and has been ignored.", where);
    }
-  } else {
-    return 0;
  }
+  return response;
 }

 // remember to free the returned array of strings.
@@ -2322,6 +2339,8 @@ int get_device_id(uint8_t *id, int int_length) {

  int64_t time_to_wait;
  do {
+    int oldState;
+    pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
    if (getifaddrs(&ifaddr) == 0) {
      t = id;
      int found = 0;
@@ -2361,6 +2380,7 @@ int get_device_id(uint8_t *id, int int_length) {
      }
      freeifaddrs(ifaddr);
    }
+    pthread_setcancelstate(oldState, NULL);
    // wait a little time if we haven't got a response
    if (response != 0) {
      usleep(100000);
@@ -396,13 +396,13 @@ typedef struct {
  uint32_t airplay_statusflags;
  char *airplay_fex;       // a base64-encoded version of the airplay_features in little-endian form
  char *airplay_device_id; // for the Bonjour advertisement and the GETINFO PList
-  char *airplay_pin;       // non-NULL, 4 char PIN, if required for pairing
  char *airplay_pi;        // UUID in the Bonjour advertisement and the GETINFO Plist
  char *airplay_pgid;      // UUID in the txtAirPlay data sent on the event channel
  char *airplay_psi;       // type 4 fixed UUID
  uint8_t airplay_pk[32];  // public key
  char *pk_string;
  char *nqptp_shared_memory_interface_name; // client name for nqptp service
+  int enable_HK_Access_Control; // true if the device is part of an Apple Home
 #endif
  int unfixable_error_reported; // only report once.

@@ -478,19 +478,6 @@ uint16_t nextFreeUDPPort();

 extern volatile int debuglev;

-void _die(const char *filename, const int linenumber, const char *format, ...);
-void _warn(const char *filename, const int linenumber, const char *format, ...);
-void _inform(const char *filename, const int linenumber, const char *format, ...);
-void _debug(const char *filename, const int linenumber, int level, const char *format, ...);
-void _debug_print_buffer(const char *thefilename, const int linenumber, int level, void *buf,
-                         size_t buf_len);
-
-#define die(...) _die(__FILE__, __LINE__, __VA_ARGS__)
-#define debug(...) _debug(__FILE__, __LINE__, __VA_ARGS__)
-#define warn(...) _warn(__FILE__, __LINE__, __VA_ARGS__)
-#define inform(...) _inform(__FILE__, __LINE__, __VA_ARGS__)
-#define debug_print_buffer(...) _debug_print_buffer(__FILE__, __LINE__, __VA_ARGS__)
-
 // Thanks to https://stackoverflow.com/a/1597129 for the inspiration for this identifier generation
 #define MAKEUNIQUEID2(x, y) x##y
 #define MADEID(x, y) MAKEUNIQUEID2(x, y)
@@ -561,7 +548,7 @@ extern int type_of_exit_cleanup; // normal, emergency, dbus requested...
 extern uint64_t minimum_dac_queue_size;

 int config_lookup_non_empty_string(const config_t *cfg, const char *path, const char **value);
-int config_set_lookup_bool(config_t *cfg, char *where, int *dst);
+int config_set_lookup_bool(config_t *cfg, const char *where, int *dst);
 int check_string_or_list_setting(config_setting_t *setting, const char *item);
 int check_int_or_list_setting(config_setting_t *setting, const int item);

@@ -1,7 +1,7 @@
 # Process this file with autoconf to produce a configure script.

 AC_PREREQ([2.50])
-AC_INIT([shairport-sync], [5.0.1+], [4265913+mikebrady@users.noreply.github.com])
+AC_INIT([shairport-sync], [5.0.4-dev], [4265913+mikebrady@users.noreply.github.com])
 : ${CFLAGS="-O3"}
 : ${CXXFLAGS="-O3"}
 AM_INIT_AUTOMAKE([subdir-objects])
@@ -219,6 +219,12 @@ fi
 # Look for metadata flag and resolve it further down the script
 AC_ARG_WITH(metadata,[AS_HELP_STRING([--with-metadata],[include support for a metadata feed])])

+# Look for metadata_pipe flag and resolve it further down the script
+AC_ARG_WITH(metadata_pipe,[AS_HELP_STRING([--with-metadata-pipe],[include support for piping metadata out through a unix pipe])])
+
+# Look for metadata_multicast flag and resolve it further down the script
+AC_ARG_WITH(metadata_multicast,[AS_HELP_STRING([--with-metadata-multicast],[include support for metadata multicasting])])
+
 # What follows is a bit messy, because if the relevant library is requested, a compiler flag is defined, a file is included in the compilation
 # and the relevant link files are added.

@@ -228,8 +234,8 @@ if test "x$with_avahi" = "xyes" ; then
  AC_DEFINE([CONFIG_AVAHI], 1, [Include Avahi-based mDNS support.])
  AC_CHECK_LIB([avahi-client], [avahi_client_new], , AC_MSG_ERROR(Avahi support requires the avahi-client library!))
  AC_CHECK_LIB([avahi-common],[avahi_strerror], , AC_MSG_ERROR(Avahi support requires the avahi-common library!))
-  systemd_after_args="${systemd_after_args} avahi-daemon.service"
-  systemd_requires_args="${systemd_requires_args} avahi-daemon.service"
+  systemd_after_args="${systemd_after_args}${systemd_after_args:+ }avahi-daemon.service"
+  systemd_requires_args="${systemd_requires_args}${systemd_requires_args:+ }avahi-daemon.service"
 fi
 AM_CONDITIONAL([USE_AVAHI], [test "x$with_avahi" = "xyes"])

@@ -404,14 +410,33 @@ fi
 AM_CONDITIONAL([USE_METADATA_HUB], [test "x$REQUESTED_EXTENDED_METADATA_SUPPORT" = "x1"])
 AM_CONDITIONAL([USE_DACP_CLIENT], [test "x$REQUESTED_EXTENDED_METADATA_SUPPORT" = "x1"])

-if test "x$REQUESTED_EXTENDED_METADATA_SUPPORT" = "x1" || test "x$with_metadata" = "xyes" ; then
+if test "x$REQUESTED_EXTENDED_METADATA_SUPPORT" = "x1" || test "x$with_metadata" = "xyes" || test "x$with_metadata_pipe" = "xyes" || test "x$with_metadata_multicast" = "xyes" ; then
+  REQUESTED_METADATA_SUPPORT=1
+fi
+
+if test "x$REQUESTED_METADATA_SUPPORT" = "x1" ; then
  AC_DEFINE([CONFIG_METADATA], 1, [Needed by the compiler.])
 fi
-AM_CONDITIONAL([USE_METADATA], [test "x$with_metadata" = "xyes"])
+AM_CONDITIONAL([USE_METADATA], [test "x$REQUESTED_METADATA_SUPPORT" = "x1"])
+
+if test "x$with_metadata" = "xyes" ; then
+  DEFAULT_INCLUDE_PIPE_METADATA=1
+fi
+
+if test "x$DEFAULT_INCLUDE_PIPE_METADATA" = "x1" || test "x$with_metadata_pipe" = "xyes" ; then
+  AC_DEFINE([CONFIG_METADATA_PIPE], 1, [Needed by the compiler.])
+fi
+AM_CONDITIONAL([USE_METADATA_PIPE], [test "x$DEFAULT_INCLUDE_PIPE_METADATA" = "x1" || test "x$with_metadata_pipe" = "xyes"])
+
+if test "x$with_metadata_multicast" = "xyes" ; then
+  AC_DEFINE([CONFIG_METADATA_MULTICAST], 1, [Needed by the compiler.])
+fi
+AM_CONDITIONAL([USE_METADATA_MULTICAST], [test "x$with_metadata_multicast" = "xyes"])

 # Look for AirPlay 2 flag
 AC_ARG_WITH(airplay-2, [AS_HELP_STRING([--with-airplay-2],[Build for AirPlay 2])])
 if test "x$with_airplay_2" = "xyes" ; then
+  using_ffmpeg=true
  AC_DEFINE([CONFIG_AIRPLAY_2], 1, [Build for AirPlay 2])
  AC_CHECK_PROG(PLISTUTIL_CHECK,plistutil,yes)
  AS_IF([test x"$PLISTUTIL_CHECK" != x"yes"], [AC_MSG_ERROR([plistutil can not be found. Please install plistutil for building for AirPlay 2. Maybe it's in the apt package libplist-utils.])])
@@ -443,6 +468,8 @@ if test "x$with_airplay_2" = "xyes" ; then
    )
  ])
  AC_CHECK_LIB([uuid],[uuid_generate], [], [AC_MSG_ERROR([AirPlay 2 support requires the uuid library -- uuid-dev suggested])])
+  systemd_after_args="${systemd_after_args}${systemd_after_args:+ }nqptp.service"
+  systemd_requires_args="${systemd_requires_args}${systemd_requires_args:+ }nqptp.service"
 fi
 AM_CONDITIONAL([USE_AIRPLAY_2], [test "x$with_airplay_2" = "xyes"])

@@ -455,7 +482,7 @@ if test "x$with_ffmpeg" = "xyes" -o "x$with_airplay_2" = "xyes" ; then
  PKG_CHECK_MODULES(
    [libavutil], [libavutil],
    [CFLAGS="${libavutil_CFLAGS} ${CFLAGS}" LIBS="${libavutil_LIBS} ${LIBS}"],
-    [AC_MSG_ERROR(AirPlay 2 support requires libavutil -- libavutil-dev suggested)]
+    [AC_MSG_ERROR(FFmpeg requires libavutil -- libavutil-dev suggested)]
  )
  PKG_CHECK_MODULES(
    [libavcodec], [libavcodec],
@@ -463,7 +490,7 @@ if test "x$with_ffmpeg" = "xyes" -o "x$with_airplay_2" = "xyes" ; then
    [AC_CHECK_LIB(
      [avcodec], [avcodec_find_decoder],
      [],
-      [AC_MSG_ERROR(AirPlay 2 support requires libavcodec -- libavcodec-dev suggested)]
+      [AC_MSG_ERROR(FFmpeg requires libavcodec -- libavcodec-dev suggested)]
    )]
  )
  PKG_CHECK_MODULES(
@@ -472,7 +499,7 @@ if test "x$with_ffmpeg" = "xyes" -o "x$with_airplay_2" = "xyes" ; then
    [AC_CHECK_LIB(
      [avformat], [avformat_new_stream],
      [],
-      [AC_MSG_ERROR([AirPlay 2 support requires libavformat -- libavformat-dev suggested])]
+      [AC_MSG_ERROR([FFmpeg requires libavformat -- libavformat-dev suggested])]
    )]
  )
  PKG_CHECK_MODULES(
@@ -481,16 +508,7 @@ if test "x$with_ffmpeg" = "xyes" -o "x$with_airplay_2" = "xyes" ; then
    [AC_CHECK_LIB(
      [swresample], [swr_convert],
      [],
-      [AC_MSG_ERROR([AirPlay 2 support requires libswresample -- libswresample-dev suggested])]
-    )]
-  )
-  PKG_CHECK_MODULES(
-    [libuuid], [uuid],
-    [CFLAGS="${libuuid_CFLAGS} ${CFLAGS}" LIBS="${libuuid_LIBS} ${LIBS}"],
-    [AC_CHECK_LIB(
-      [uuid], [uuid_generate],
-      [],
-      [AC_MSG_ERROR([AirPlay 2 support requires the uuid library -- uuid-dev suggested])]
+      [AC_MSG_ERROR([FFmpeg requires libswresample -- libswresample-dev suggested])]
    )]
  )
 else
@@ -505,8 +523,11 @@ AM_CONDITIONAL([USE_HAMMERTON], [test $using_ffmpeg = false])
 # Look for Apple ALAC flag
 AC_ARG_WITH(apple-alac,[AS_HELP_STRING([--with-apple-alac],[include support for the Apple ALAC decoder (deprecated)])])
 if test "x${with_apple_alac}"  = "xyes" ; then
+  if test "x${with_airplay_2}"  = "xyes" ; then
+    AC_MSG_ERROR([the Apple ALAC Decoder (deprecated) can not be used in AirPlay 2.])
+  fi
  if test $using_ffmpeg = true ; then
-    AC_MSG_RESULT([Note: the FFMPEG decoder, included in the build, supercedes the Apple ALAC decoder, which is deprecated. Consider omitting the Apple ALAC decoder.])
+    AC_MSG_WARN([the FFMPEG decoder, included in the build, supercedes the Apple ALAC Decoder, which is deprecated. Consider omitting the Apple ALAC Decoder.])
  fi 
  AC_DEFINE([CONFIG_APPLE_ALAC], 1, [Include support for using the Apple ALAC Decoder (deprecated)])
  if  test "x${with_pkg_config}" = xyes ; then
@@ -43,7 +43,7 @@
 #include <time.h>
 #include <unistd.h>

-#include "metadata_hub.h"
+#include "metadata/hub.h"
 #include "tinyhttp/http.h"

 typedef struct {
@@ -397,10 +397,10 @@ void relinquish_dacp_server_information(rtsp_conn_info *conn) {
  // as the conn's connection number
  // this is to signify that the player has stopped, but only if another thread (with a different
  // index) hasn't already taken over the dacp service
-  debug_mutex_lock(&dacp_server_information_lock, 500000, 2);
+  debug_mutex_lock(&dacp_server_information_lock, 500000, 4);
  if (dacp_server.players_connection_thread_index == conn->connection_number)
    dacp_server.players_connection_thread_index = 0;
-  debug_mutex_unlock(&dacp_server_information_lock, 3);
+  debug_mutex_unlock(&dacp_server_information_lock, 4);
 }

 // this will be running on the thread of its caller, not of the conversation thread...
@@ -37,8 +37,11 @@

 #include "rtp.h"

+#ifdef CONFIG_DACP_CLIENT
 #include "dacp.h"
-#include "metadata_hub.h"
+#endif
+
+#include "metadata/hub.h"

 #include "dbus-service.h"

@@ -335,7 +338,9 @@ static gboolean on_handle_set_volume(ShairportSyncAdvancedRemoteControl *skeleto
                                     GDBusMethodInvocation *invocation, const gint volume,
                                     __attribute__((unused)) gpointer user_data) {
  debug(2, "Set volume to %d.", volume);
+#ifdef CONFIG_DACP_CLIENT
  dacp_set_volume(volume);
+#endif
  shairport_sync_advanced_remote_control_complete_set_volume(skeleton, invocation);
  return TRUE;
 }
@@ -343,7 +348,9 @@ static gboolean on_handle_set_volume(ShairportSyncAdvancedRemoteControl *skeleto
 static gboolean on_handle_fast_forward(ShairportSyncRemoteControl *skeleton,
                                       GDBusMethodInvocation *invocation,
                                       __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("beginff");
+#endif
  shairport_sync_remote_control_complete_fast_forward(skeleton, invocation);
  return TRUE;
 }
@@ -351,7 +358,9 @@ static gboolean on_handle_fast_forward(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_rewind(ShairportSyncRemoteControl *skeleton,
                                 GDBusMethodInvocation *invocation,
                                 __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("beginrew");
+#endif
  shairport_sync_remote_control_complete_rewind(skeleton, invocation);
  return TRUE;
 }
@@ -359,7 +368,9 @@ static gboolean on_handle_rewind(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_toggle_mute(ShairportSyncRemoteControl *skeleton,
                                      GDBusMethodInvocation *invocation,
                                      __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("mutetoggle");
+#endif
  shairport_sync_remote_control_complete_toggle_mute(skeleton, invocation);
  return TRUE;
 }
@@ -367,7 +378,9 @@ static gboolean on_handle_toggle_mute(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_next(ShairportSyncRemoteControl *skeleton,
                               GDBusMethodInvocation *invocation,
                               __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("nextitem");
+#endif
  shairport_sync_remote_control_complete_next(skeleton, invocation);
  return TRUE;
 }
@@ -375,7 +388,9 @@ static gboolean on_handle_next(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_previous(ShairportSyncRemoteControl *skeleton,
                                   GDBusMethodInvocation *invocation,
                                   __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("previtem");
+#endif
  shairport_sync_remote_control_complete_previous(skeleton, invocation);
  return TRUE;
 }
@@ -383,7 +398,9 @@ static gboolean on_handle_previous(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_pause(ShairportSyncRemoteControl *skeleton,
                                GDBusMethodInvocation *invocation,
                                __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("pause");
+#endif
  shairport_sync_remote_control_complete_pause(skeleton, invocation);
  return TRUE;
 }
@@ -391,7 +408,9 @@ static gboolean on_handle_pause(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_play_pause(ShairportSyncRemoteControl *skeleton,
                                     GDBusMethodInvocation *invocation,
                                     __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("playpause");
+#endif
  shairport_sync_remote_control_complete_play_pause(skeleton, invocation);
  return TRUE;
 }
@@ -399,7 +418,9 @@ static gboolean on_handle_play_pause(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_play(ShairportSyncRemoteControl *skeleton,
                               GDBusMethodInvocation *invocation,
                               __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT                               
  send_simple_dacp_command("play");
+#endif
  shairport_sync_remote_control_complete_play(skeleton, invocation);
  return TRUE;
 }
@@ -407,7 +428,9 @@ static gboolean on_handle_play(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_stop(ShairportSyncRemoteControl *skeleton,
                               GDBusMethodInvocation *invocation,
                               __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("stop");
+#endif
  shairport_sync_remote_control_complete_stop(skeleton, invocation);
  return TRUE;
 }
@@ -415,7 +438,9 @@ static gboolean on_handle_stop(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_resume(ShairportSyncRemoteControl *skeleton,
                                 GDBusMethodInvocation *invocation,
                                 __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("playresume");
+#endif
  shairport_sync_remote_control_complete_resume(skeleton, invocation);
  return TRUE;
 }
@@ -423,7 +448,9 @@ static gboolean on_handle_resume(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_shuffle_songs(ShairportSyncRemoteControl *skeleton,
                                        GDBusMethodInvocation *invocation,
                                        __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("shuffle_songs");
+#endif
  shairport_sync_remote_control_complete_shuffle_songs(skeleton, invocation);
  return TRUE;
 }
@@ -431,7 +458,9 @@ static gboolean on_handle_shuffle_songs(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_volume_up(ShairportSyncRemoteControl *skeleton,
                                    GDBusMethodInvocation *invocation,
                                    __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("volumeup");
+#endif
  shairport_sync_remote_control_complete_volume_up(skeleton, invocation);
  return TRUE;
 }
@@ -439,7 +468,9 @@ static gboolean on_handle_volume_up(ShairportSyncRemoteControl *skeleton,
 static gboolean on_handle_volume_down(ShairportSyncRemoteControl *skeleton,
                                      GDBusMethodInvocation *invocation,
                                      __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("volumedown");
+#endif
  shairport_sync_remote_control_complete_volume_down(skeleton, invocation);
  return TRUE;
 }
@@ -449,9 +480,11 @@ static gboolean on_handle_set_airplay_volume(ShairportSyncRemoteControl *skeleto
                                             const gdouble volume,
                                             __attribute__((unused)) gpointer user_data) {
  debug(2, "Set airplay volume to %.6f.", volume);
+#ifdef CONFIG_DACP_CLIENT
  char command[256] = "";
  snprintf(command, sizeof(command), "setproperty?dmcp.device-volume=%.6f", volume);
  send_simple_dacp_command(command);
+#endif
  shairport_sync_remote_control_complete_set_airplay_volume(skeleton, invocation);
  return TRUE;
 }
@@ -683,17 +716,7 @@ gboolean notify_volume_callback(ShairportSync *skeleton,
  gdouble iv = shairport_sync_get_volume(skeleton);
  if (((iv >= -30.0) && (iv <= 0.0)) || (iv == -144.0)) {
    debug(2, ">> set volume to %7.4f.", iv);
-
-    pthread_rwlock_rdlock(&principal_conn_lock); // don't let the principal_conn be changed
-    pthread_cleanup_push(rwlock_unlock, (void *)&principal_conn_lock);
-
-    if (principal_conn != NULL) {
-      player_volume(iv, principal_conn);
-      principal_conn->own_airplay_volume = iv;
-      principal_conn->own_airplay_volume_set = 1;
-    }
-    pthread_cleanup_pop(1); // release the principal_conn lock
-    config.airplay_volume = iv;
+    config.airplay_volume = iv;  
  } else {
    debug(1, ">> invalid volume: %f. Ignored.", iv);
    shairport_sync_set_volume(skeleton, config.airplay_volume);
@@ -737,6 +760,12 @@ gboolean notify_alacdecoder_callback(ShairportSync *skeleton,
                                     __attribute__((unused)) gpointer user_data) {
  char *th = (char *)shairport_sync_get_alacdecoder(skeleton);

+#ifdef CONFIG_AIRPLAY_2 
+  if (strcasecmp(th, "ffmpeg") != 0) {
+    warn(" This request, to set the decoder to \"%s\", is ignored. For AirPlay 2, the FFmpeg decoder is always used.",
+         th);
+  }
+#else
  if ((strcasecmp(th, "hammerton") == 0) &&
      ((config.decoders_supported & (1 << decoder_hammerton)) != 0))
    config.decoder_in_use = 1 << decoder_hammerton;
@@ -747,12 +776,13 @@ gboolean notify_alacdecoder_callback(ShairportSync *skeleton,
           ((config.decoders_supported & (1 << decoder_ffmpeg_alac)) != 0))
    config.decoder_in_use = 1 << decoder_ffmpeg_alac;
  else {
-    warn("An unrecognised or unsupported ALAC decoder: \"%s\" was requested via D-Bus interface. "
+    warn("An unrecognised or unsupported decoder: \"%s\" was requested via D-Bus interface. "
         "(Possibly "
         "support for this decoder was not compiled "
         "into this version of Shairport Sync.)",
         th);
  }
+#endif

  return TRUE;
 }
@@ -838,6 +868,7 @@ gboolean notify_volume_control_profile_callback(ShairportSync *skeleton,
  return TRUE;
 }

+#ifdef CONFIG_DACP_CLIENT
 gboolean notify_shuffle_callback(ShairportSyncAdvancedRemoteControl *skeleton,
                                 __attribute__((unused)) gpointer user_data) {
  // debug(1,"notify_shuffle_callback called");
@@ -847,9 +878,17 @@ gboolean notify_shuffle_callback(ShairportSyncAdvancedRemoteControl *skeleton,
    send_simple_dacp_command("setproperty?dacp.shufflestate=0");
  return TRUE;
 }
+#else
+gboolean notify_shuffle_callback(__attribute__((unused)) ShairportSyncAdvancedRemoteControl *skeleton,
+                                 __attribute__((unused)) gpointer user_data) {
+  return TRUE;
+}
+#endif

+#ifdef CONFIG_DACP_CLIENT
 gboolean notify_loop_status_callback(ShairportSyncAdvancedRemoteControl *skeleton,
                                     __attribute__((unused)) gpointer user_data) {
+
  // debug(1,"notify_loop_status_callback called");
  char *th = (char *)shairport_sync_advanced_remote_control_get_loop_status(skeleton);
  //  enum volume_control_profile_type previous_volume_control_profile =
@@ -884,6 +923,12 @@ gboolean notify_loop_status_callback(ShairportSyncAdvancedRemoteControl *skeleto
  }
  return TRUE;
 }
+#else
+gboolean notify_loop_status_callback(__attribute__((unused)) ShairportSyncAdvancedRemoteControl *skeleton,
+                                     __attribute__((unused)) gpointer user_data) {
+  return TRUE;
+}
+#endif

 static gboolean on_handle_quit(ShairportSync *skeleton, GDBusMethodInvocation *invocation,
                               __attribute__((unused)) const gchar *command,
@@ -900,10 +945,12 @@ static gboolean on_handle_remote_command(ShairportSync *skeleton, GDBusMethodInv
                                         __attribute__((unused)) gpointer user_data) {
  debug(1, "RemoteCommand with command \"%s\".", command);
  int reply = 0;
+  char *client_reply_hex = "";
+#ifdef CONFIG_DACP_CLIENT
  char *client_reply = NULL;
  ssize_t reply_size = 0;
  reply = dacp_send_command((const char *)command, &client_reply, &reply_size);
-  char *client_reply_hex = alloca(reply_size * 2 + 1);
+  client_reply_hex = alloca(reply_size * 2 + 1);
  if (client_reply_hex) {
    char *p = client_reply_hex;
    if (client_reply) {
@@ -917,6 +964,7 @@ static gboolean on_handle_remote_command(ShairportSync *skeleton, GDBusMethodInv
    }
    *p = '\0';
  }
+#endif
  shairport_sync_complete_remote_command(skeleton, invocation, reply, client_reply_hex);
  return TRUE;
 }
@@ -958,7 +1006,6 @@ static void on_dbus_name_acquired(GDBusConnection *connection, const gchar *name

  shairportSyncAdvancedRemoteControlSkeleton =
      shairport_sync_advanced_remote_control_skeleton_new();
-
  g_dbus_interface_skeleton_export(
      G_DBUS_INTERFACE_SKELETON(shairportSyncAdvancedRemoteControlSkeleton), connection,
      "/org/gnome/ShairportSync", NULL);
@@ -1015,9 +1062,10 @@ static void on_dbus_name_acquired(GDBusConnection *connection, const gchar *name

  g_signal_connect(shairportSyncDiagnosticsSkeleton, "notify::file-and-line",
                   G_CALLBACK(notify_file_and_line_callback), NULL);
-
+  
  g_signal_connect(shairportSyncRemoteControlSkeleton, "handle-fast-forward",
                   G_CALLBACK(on_handle_fast_forward), NULL);
+          
  g_signal_connect(shairportSyncRemoteControlSkeleton, "handle-rewind",
                   G_CALLBACK(on_handle_rewind), NULL);
  g_signal_connect(shairportSyncRemoteControlSkeleton, "handle-toggle-mute",
@@ -5,6 +5,10 @@

 #include "config.h"

+
+// for generating our own UUIDs
+#define SHAIRPORT_SYNC_DEVICE_NAMESPACE "01d7c137-6316-455d-a52f-dfb529f26adf"
+
 #if defined(__APPLE__) && defined(__MACH__)
 /* Apple OSX and iOS (Darwin). ------------------------------ */
 #include <TargetConditionals.h>
@@ -32,7 +32,11 @@

 #include "common.h"
 #include "mdns.h"
-#include "rtsp.h"
+
+#ifdef CONFIG_METADATA
+#include "metadata/core.h"
+#endif
+
 #ifdef CONFIG_DACP_CLIENT
 #include "dacp.h"
 #endif
@@ -0,0 +1,310 @@
+/*
+ * Core metadata handler.
+ * This file is part of Shairport Sync.
+ * Copyright (c) Mike Brady 2017--2026
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+#include "core.h"
+#include "pc_queue.h"
+
+#include <stdlib.h>
+#include <inttypes.h>
+#include <sys/stat.h>
+#include <string.h>
+#include <errno.h>
+
+#ifdef CONFIG_METADATA_PIPE
+#include "pipe.h"
+#endif
+
+#ifdef CONFIG_METADATA_MULTICAST
+#include "multicast.h"
+#endif
+
+#ifdef CONFIG_METADATA_HUB
+#include "hub.h"
+#endif
+
+#ifdef CONFIG_MQTT
+#include "mqtt.h"
+#endif
+
+
+// Metadata is not used by shairport-sync.
+// Instead we send all metadata to a fifo pipe, so that other apps can listen to
+// the pipe and use the metadata.
+
+// We use two 4-character codes to identify each piece of data and we send the
+// data itself, if any,
+// in base64 form.
+
+// The first 4-character code, called the "type", is either:
+//    'core' for all the regular metadadata coming from iTunes, etc., or
+//    'ssnc' (for 'shairport-sync') for all metadata coming from Shairport Sync
+//    itself, such as
+//    start/end delimiters, etc.
+
+// For 'core' metadata, the second 4-character code is the 4-character metadata
+// code coming from
+// iTunes etc.
+// For 'ssnc' metadata, the second 4-character code is used to distinguish the
+// messages.
+
+// Cover art is not tagged in the same way as other metadata, it seems, so is
+// sent as an 'ssnc' type
+// metadata message with the code 'PICT'
+// Here are the 'ssnc' codes defined so far:
+//    'PICT' -- the payload is a picture, either a JPEG or a PNG. Check the
+//    first few bytes to see
+//    which.
+//    'abeg' -- active mode entered. No arguments
+//    'aend' -- active mode exited. No arguments
+//    'pbeg' -- play stream begin. No arguments
+//    'pend' -- play stream end. No arguments
+//    'pfls' -- play stream flush. The argument is an unsigned 32-bit
+//               frame number. It seems that all frames up to but not
+//               including this frame are to be flushed.
+//
+//    'prsm' -- play stream resume. No arguments. (deprecated)
+//    'paus' -- buffered audio stream paused. No arguments.
+//    'pres' -- buffered audio stream resumed. No arguments.
+//		'pffr' -- the first frame of a play session has been received and has been validly
+//              timed. The argument is
+//              "<frame_number>/<time_it_should_be_played_in_64_bit_nanoseconds>"."
+//		'pdis' -- a discontinuity in the timestamps of incoming frames has been detected.
+//              timed. The argument is  "<frame_number>/<discontinuity>".
+//              discontinuity is the actual frame number less the expected frame number
+//              positive means a gap
+//    'pvol' -- play volume. The volume is sent as a string --
+//    "airplay_volume,volume,lowest_volume,highest_volume"
+//              volume, lowest_volume and highest_volume are given in dB.
+//              The "airplay_volume" is what's sent to the player, and is from
+//              0.00 down to -30.00,
+//              with -144.00 meaning mute.
+//              This is linear on the volume control slider of iTunes or iOS
+//              AirPlay.
+//    'prgr' -- progress -- this is metadata from AirPlay consisting of RTP
+//    timestamps for the start
+//    of the current play sequence, the current play point and the end of the
+//    play sequence.
+//              I guess the timestamps wrap at 2^32.
+//    'mdst' -- a sequence of metadata is about to start; will have, as data,
+//    the rtptime associated with the metadata, if available
+//    'mden' -- a sequence of metadata has ended; will have, as data, the
+//    rtptime associated with the metadata, if available
+//    'pcst' -- a picture is about to be sent; will have, as data, the rtptime
+//    associated with the picture, if available
+//    'pcen' -- a picture has been sent; will have, as data, the rtptime
+//    associated with the metadata, if available
+//    'snam' -- A device -- e.g. "Joe's iPhone" -- has opened a play session.
+//    Specifically, it's the "X-Apple-Client-Name" string
+//    'snua' -- A "user agent" -- e.g. "iTunes/12..." -- has opened a play
+//    session. Specifically, it's the "User-Agent" string
+//    The next two two tokens are to facilitate remote control of the source.
+//    There is some information at http://nto.github.io/AirPlay.html about
+//    remote control of the source.
+//
+//    'daid' -- this is the source's DACP-ID (if it has one -- it's not
+//    guaranteed), useful if you want to remotely control the source. Use this
+//    string to identify the source's remote control on the network.
+//    'acre' -- this is the source's Active-Remote token, necessary if you want
+//    to send commands to the source's remote control (if it has one).
+//		`clip` -- the payload is the IP number of the client, i.e. the sender of audio.
+//		Can be an IPv4 or an IPv6 number. In AirPlay 2 operation, it is sent as soon
+//    as the client has exclusive access to the player and after any existing
+//    play session has been interrupted and terminated.
+//		`conn` -- the payload is the IP number of the client, i.e. the sender of audio.
+//		Can be an IPv4 or an IPv6 number. This is an AirPlay-2-only message.
+//    It is sent as soon as the client requests access to the player.
+//    If Shairport Sync is already playing, this message is sent before the current
+//    play session is stopped.
+//		`svip` -- the payload is the IP number of the server, i.e. the player itself.
+//		Can be an IPv4 or an IPv6 number.
+//		`svna` -- the payload is the service name of the player, i.e. the name by
+//		which it is seen in the AirPlay menu.
+//    `disc` -- the payload is the IP number of the client, i.e. the sender of audio.
+//		Can be an IPv4 or an IPv6 number. This is an AirPlay-2-only message.
+//    It is sent when a client has been disconnected.
+//		`dapo` -- the payload is the port number (as text) on the server to which remote
+// control commands should be sent. It is 3689 for iTunes but varies for iOS devices.
+//    ``
+
+int metadata_running = 0;
+
+void metadata_pack_cleanup_function(void *arg) {
+  // debug(1, "metadata_pack_cleanup_function called");
+  metadata_package *pack = (metadata_package *)arg;
+  if (pack->carrier)
+    msg_free(&pack->carrier); // release the message
+  else if (pack->data)
+    free(pack->data);
+  // debug(1, "metadata_pack_cleanup_function exit");
+}
+
+void metadata_init(void) {
+
+#ifdef CONFIG_METADATA_PIPE
+  metadata_pipe_queue_init();
+#endif  
+
+#ifdef CONFIG_METADATA_MULTICAST
+    metadata_multicast_queue_init();
+#endif
+
+#ifdef CONFIG_METADATA_HUB
+    metadata_hub_queue_init();
+#endif
+
+#ifdef CONFIG_MQTT
+  metadata_mqtt_queue_init();
+#endif
+  metadata_running = 1;
+}
+
+void metadata_stop(void) {
+  if (metadata_running) {
+    debug(2, "metadata_stop called.");
+
+#ifdef CONFIG_MQTT
+    metadata_mqtt_queue_stop();
+#endif
+
+#ifdef CONFIG_METADATA_HUB
+    metadata_hub_queue_stop();
+#endif
+
+#ifdef CONFIG_METADATA_MULTICAST      
+    metadata_multicast_queue_stop();
+#endif
+
+#ifdef CONFIG_METADATA_PIPE     
+    metadata_pipe_queue_stop();
+#endif
+
+  }
+}
+
+int send_metadata_to_queue(pc_queue *queue, const uint32_t type, const uint32_t code,
+                           const char *data, const uint32_t length, rtsp_message *carrier,
+                           int block) {
+
+  // clang-format off
+  // parameters:
+  //   type,
+  //   code,
+  //   pointer to data or NULL,
+  //   length of data or NULL,
+  //   the rtsp_message or NULL,
+
+  // the rtsp_message is sent for 'core' messages, because it contains the data
+  // and must not be freed until the data has been read.
+  // So, it is passed to send_metadata to be retained, sent to the thread where metadata
+  // is processed and released (and probably freed).
+
+  // The rtsp_message is also sent for certain non-'core' messages.
+
+  // The reading of the parameters is a bit complex:
+  // If the rtsp_message field is non-null, then it represents an rtsp_message
+  // and the data pointer is assumed to point to something within it.
+  // The reference counter of the rtsp_message is incremented here and
+  // should be decremented by the metadata handler when finished.
+  // If the reference count reduces to zero, the message will be freed.
+
+  // If the rtsp_message is NULL, then if the pointer is non-null then the data it
+  // points to, of the length specified, is memcpy'd and passed to the metadata
+  // handler. The handler should free it when done.
+
+  // If the rtsp_message is NULL and the pointer is also NULL, nothing further
+  // is done.
+  // clang-format on
+
+  metadata_package pack;
+  pack.type = type;
+  pack.code = code;
+  pack.length = length;
+  pack.carrier = carrier;
+  pack.data = (char *)data;
+  if (pack.carrier) {
+    msg_retain(pack.carrier);
+  } else {
+    if (data)
+      pack.data = memdup(data, length); // only if it's not a null
+  }
+
+  // debug(1, "send_metadata_to_queue %x/%x", type, code);
+  int rc = pc_queue_add_item(queue, &pack, block);
+  if (rc != 0) {
+    if (pack.carrier) {
+      if (rc == EWOULDBLOCK)
+        debug(2,
+              "metadata queue \"%s\" full, dropping message item: type %x, code %x, data %" PRIxPTR ", "
+              "length %u, message %d.",
+              queue->name, pack.type, pack.code, (uintptr_t)pack.data, pack.length,
+              pack.carrier->index_number);
+      msg_free(&pack.carrier);
+    } else {
+      if (rc == EWOULDBLOCK)
+        debug(
+            2,
+            "metadata queue \"%s\" full, dropping data item: type %x, code %x, data %" PRIxPTR ", length %u.",
+            queue->name, pack.type, pack.code, (uintptr_t)pack.data, pack.length);
+      if (pack.data)
+        free(pack.data);
+    }
+  }
+  return rc;
+}
+
+int send_metadata(const uint32_t type, const uint32_t code, const char *data, const uint32_t length,
+                  rtsp_message *carrier, int block) {
+  int rc = 0;
+  if (config.metadata_enabled) {
+
+#ifdef CONFIG_METADATA_PIPE
+    rc = send_metadata_to_pipe_queue(type, code, data, length, carrier, block);
+#endif
+
+#ifdef CONFIG_METADATA_MULTICAST
+    rc =
+        send_metadata_to_multicast_queue(type, code, data, length, carrier, block);
+#endif
+
+#ifdef CONFIG_METADATA_HUB
+    rc = send_metadata_to_hub_queue(type, code, data, length, carrier, block);
+#endif
+
+#ifdef CONFIG_MQTT
+    rc = send_metadata_to_mqtt_queue(type, code, data, length, carrier, block);
+#endif
+
+  }
+  return rc;
+}
+
+int send_ssnc_metadata(const uint32_t code, const char *data, const uint32_t length,
+                       const int block) {
+  return send_metadata('ssnc', code, data, length, NULL, block);
+}
+
@@ -0,0 +1,39 @@
+#pragma once
+
+#include "common.h"
+#include "config.h"
+#include "../rtsp.h"
+#include "pc_queue.h"
+#include <pthread.h>
+
+typedef struct {
+  uint32_t type;
+  uint32_t code;
+  char *data;
+  uint32_t length;
+  rtsp_message *carrier;
+} metadata_package;
+
+void metadata_pack_cleanup_function(void *arg);
+
+// initialise and completely delete the metadata stuff
+
+void metadata_init(void);
+void metadata_stop(void);
+
+
+int send_metadata_to_queue(pc_queue *queue, const uint32_t type, const uint32_t code,
+                           const char *data, const uint32_t length, rtsp_message *carrier,
+                           int block);
+
+// sends metadata out to the metadata system.
+
+int send_metadata(const uint32_t type, const uint32_t code, const char *data, const uint32_t length,
+                  rtsp_message *carrier, int block);
+
+// It is sent with the type 'ssnc' the given code, data and length
+// The handler at the other end must know what to do with the data
+// e.g. if it's malloced, to free it, etc.
+// nothing is done automatically
+int send_ssnc_metadata(const uint32_t code, const char *data, const uint32_t length,
+                       const int block);
@@ -5,7 +5,7 @@
 * then you need a metadata hub,
 * where everything is stored
 * This file is part of Shairport Sync.
- * Copyright (c) Mike Brady 2017--2025
+ * Copyright (c) Mike Brady 2017--2026
 * All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person
@@ -44,7 +44,9 @@

 #include "common.h"
 #include "dacp.h"
-#include "metadata_hub.h"
+#include "hub.h"
+#include "pc_queue.h"
+#include "core.h"

 #ifdef CONFIG_MBEDTLS
 #include <mbedtls/md5.h>
@@ -59,6 +61,12 @@
 #include <openssl/evp.h>
 #endif

+// metadata queue definitions
+pc_queue metadata_hub_queue;
+#define metadata_hub_queue_size 500
+metadata_package metadata_hub_queue_items[metadata_hub_queue_size];
+pthread_t metadata_hub_thread;
+
 struct metadata_bundle metadata_store;

 int metadata_hub_initialised = 0;
@@ -710,3 +718,56 @@ void metadata_hub_process_metadata(uint32_t type, uint32_t code, char *data, uin
  pthread_cleanup_pop(0); // don't remove the lock
  metadata_hub_modify_epilog(changed);
 }
+
+void metadata_hub_close(void) {}
+
+void metadata_hub_thread_cleanup_function(__attribute__((unused)) void *arg) {
+  // debug(2, "metadata_hub_thread_cleanup_function called");
+  metadata_hub_close();
+}
+
+void *metadata_hub_thread_function(__attribute__((unused)) void *ignore) {
+  //  #include <syscall.h>
+  //  debug(1, "metadata_hub_thread_function PID %d", syscall(SYS_gettid));
+  metadata_package pack;
+  pthread_cleanup_push(metadata_hub_thread_cleanup_function, NULL);
+  while (1) {
+    pc_queue_get_item(&metadata_hub_queue, &pack);
+    pthread_cleanup_push(metadata_pack_cleanup_function, (void *)&pack);
+    if (pack.carrier) {
+      debug(4, "                    hub: type %x, code %x, length %u, message %d.", pack.type,
+            pack.code, pack.length, pack.carrier->index_number);
+    } else {
+      debug(4, "                    hub: type %x, code %x, length %u.", pack.type, pack.code,
+            pack.length);
+    }
+    metadata_hub_process_metadata(pack.type, pack.code, pack.data, pack.length);
+    debug(4, "                    hub: done.");
+    pthread_cleanup_pop(1);
+  }
+  pthread_cleanup_pop(1); // will never happen
+  pthread_exit(NULL);
+}
+
+void metadata_hub_queue_init() {
+  // create a pc_queue for the metadata hub
+  pc_queue_init(&metadata_hub_queue, (char *)&metadata_hub_queue_items, sizeof(metadata_package),
+                metadata_hub_queue_size, "hub");
+  if (named_pthread_create(&metadata_hub_thread, NULL, metadata_hub_thread_function, NULL,
+                           "metadata hub") != 0)
+    debug(1, "Failed to create metadata hub thread!");
+}
+
+void metadata_hub_queue_stop() {
+    // debug(2, "metadata stop hub thread.");
+    pthread_cancel(metadata_hub_thread);
+    pthread_join(metadata_hub_thread, NULL);
+    pc_queue_delete(&metadata_hub_queue);
+    // debug(2, "metadata stop hub done.");
+}
+
+int send_metadata_to_hub_queue(const uint32_t type, const uint32_t code,
+                           const char *data, const uint32_t length, rtsp_message *carrier,
+                           int block) {
+    return send_metadata_to_queue(&metadata_hub_queue, type, code, data, length, carrier, block);
+}
@@ -1,6 +1,7 @@
 #pragma once
 #include "common.h"
 #include "config.h"
+#include "rtsp.h"
 #include <pthread.h>

 #define number_of_watchers 2
@@ -189,3 +190,11 @@ void _metadata_hub_read_epilog(const char *filename, const int linenumber);

 #define metadata_hub_read_prolog(void) _metadata_hub_read_prolog(__FILE__, __LINE__)
 #define metadata_hub_read_epilog(void) _metadata_hub_modify_epilog(__FILE__, __LINE__)
+
+// metadata queue stuff
+void metadata_hub_queue_init();
+void metadata_hub_queue_stop();
+int send_metadata_to_hub_queue(const uint32_t type, const uint32_t code,
+                           const char *data, const uint32_t length, rtsp_message *carrier,
+                           int block);
+
@@ -0,0 +1,180 @@
+  #include "multicast.h"
+  #include "core.h"
+  #include "pc_queue.h"
+  
+  #include <stdlib.h>
+  #include <string.h>
+  
+  
+//		A special sub-protocol is used for sending large data items over UDP
+//    If the payload exceeded 4 MB, it is chunked using the following format:
+//    "ssnc", "chnk", packet_ix, packet_counts, packet_tag, packet_type, chunked_data.
+//    Notice that the number of items is different to the standard
+  
+#define METADATA_SNDBUF (4 * 1024 * 1024)
+static int metadata_sock = -1;
+static struct sockaddr_in metadata_sockaddr;
+static char *metadata_sockmsg;
+pc_queue metadata_multicast_queue;
+#define metadata_multicast_queue_size 500
+metadata_package metadata_multicast_queue_items[metadata_multicast_queue_size];
+pthread_t metadata_multicast_thread;
+
+int send_metadata_to_multicast_queue(const uint32_t type, const uint32_t code,
+                           const char *data, const uint32_t length, rtsp_message *carrier,
+                           int block) {
+    return send_metadata_to_queue(&metadata_multicast_queue, type, code, data, length, carrier, block);
+}
+
+void metadata_create_multicast_socket(void) {
+  if (config.metadata_enabled == 0)
+    return;
+
+  // Unlike metadata pipe, socket is opened once and stays open,
+  // so we can call it in create
+  if (config.metadata_sockaddr && config.metadata_sockport) {
+    metadata_sock = socket(AF_INET, SOCK_DGRAM, 0);
+    if (metadata_sock < 0) {
+      debug(1, "Could not open metadata socket");
+    } else {
+      int buffer_size = METADATA_SNDBUF;
+      setsockopt(metadata_sock, SOL_SOCKET, SO_SNDBUF, &buffer_size, sizeof(buffer_size));
+      bzero((char *)&metadata_sockaddr, sizeof(metadata_sockaddr));
+      metadata_sockaddr.sin_family = AF_INET;
+      metadata_sockaddr.sin_addr.s_addr = inet_addr(config.metadata_sockaddr);
+      metadata_sockaddr.sin_port = htons(config.metadata_sockport);
+      metadata_sockmsg = malloc(config.metadata_sockmsglength);
+      if (metadata_sockmsg) {
+        memset(metadata_sockmsg, 0, config.metadata_sockmsglength);
+      } else {
+        die("Could not malloc metadata multicast socket buffer");
+      }
+    }
+  }
+}
+
+void metadata_delete_multicast_socket(void) {
+  if (config.metadata_enabled == 0)
+    return;
+  if (metadata_sock != -1) {
+    shutdown(metadata_sock, SHUT_RDWR); // we want to immediately deallocate the buffer
+    close(metadata_sock);
+  }
+  if (metadata_sockmsg)
+    free(metadata_sockmsg);
+}
+
+void metadata_multicast_process(uint32_t type, uint32_t code, char *data, uint32_t length) {
+  // debug(1, "Process multicast metadata with type %x, code %x and length %u.", type, code,
+  // length);
+  if (metadata_sock >= 0 && length < config.metadata_sockmsglength - 8) {
+    char *ptr = metadata_sockmsg;
+    uint32_t v;
+    v = htonl(type);
+    memcpy(ptr, &v, 4);
+    ptr += 4;
+    v = htonl(code);
+    memcpy(ptr, &v, 4);
+    ptr += 4;
+    memcpy(ptr, data, length);
+    sendto(metadata_sock, metadata_sockmsg, length + 8, 0, (struct sockaddr *)&metadata_sockaddr,
+           sizeof(metadata_sockaddr));
+  } else if (metadata_sock >= 0) {
+    // send metadata in numbered chunks using the protocol:
+    // ("ssnc", "chnk", packet_ix, packet_counts, packet_tag, packet_type, chunked_data)
+
+    uint32_t chunk_ix = 0;
+    if (config.metadata_sockmsglength == 24)
+      die("A divide by zero almost occurred (config.metadata_sockmsglength = 24).");
+    uint32_t chunk_total = length / (config.metadata_sockmsglength - 24);
+    if (chunk_total * (config.metadata_sockmsglength - 24) < length) {
+      chunk_total++;
+    }
+    uint32_t remaining = length;
+    uint32_t v;
+    char *data_crsr = data;
+    do {
+      char *ptr = metadata_sockmsg;
+      memcpy(ptr, "ssncchnk", 8);
+      ptr += 8;
+      v = htonl(chunk_ix);
+      memcpy(ptr, &v, 4);
+      ptr += 4;
+      v = htonl(chunk_total);
+      memcpy(ptr, &v, 4);
+      ptr += 4;
+      v = htonl(type);
+      memcpy(ptr, &v, 4);
+      ptr += 4;
+      v = htonl(code);
+      memcpy(ptr, &v, 4);
+      ptr += 4;
+      size_t datalen = remaining;
+      if (datalen > config.metadata_sockmsglength - 24) {
+        datalen = config.metadata_sockmsglength - 24;
+      }
+      memcpy(ptr, data_crsr, datalen);
+      data_crsr += datalen;
+      sendto(metadata_sock, metadata_sockmsg, datalen + 24, 0,
+             (struct sockaddr *)&metadata_sockaddr, sizeof(metadata_sockaddr));
+      chunk_ix++;
+      remaining -= datalen;
+      if (remaining == 0)
+        break;
+    } while (1);
+  }
+}
+
+void metadata_multicast_thread_cleanup_function(__attribute__((unused)) void *arg) {
+  // debug(2, "metadata_multicast_thread_cleanup_function called");
+  metadata_delete_multicast_socket();
+}
+
+void *metadata_multicast_thread_function(__attribute__((unused)) void *ignore) {
+  //  #include <syscall.h>
+  //  debug(1, "metadata_multicast_thread_function PID %d", syscall(SYS_gettid));
+  metadata_create_multicast_socket();
+  metadata_package pack;
+  pthread_cleanup_push(metadata_multicast_thread_cleanup_function, NULL);
+  while (1) {
+    pc_queue_get_item(&metadata_multicast_queue, &pack);
+    pthread_cleanup_push(metadata_pack_cleanup_function, (void *)&pack);
+    if (config.metadata_enabled) {
+      if (pack.carrier) {
+        debug(4,
+              "                                                                    multicast: type "
+              "%x, code %x, length %u, message %d.",
+              pack.type, pack.code, pack.length, pack.carrier->index_number);
+      } else {
+        debug(4,
+              "                                                                    multicast: type "
+              "%x, code %x, length %u.",
+              pack.type, pack.code, pack.length);
+      }
+      metadata_multicast_process(pack.type, pack.code, pack.data, pack.length);
+      debug(4,
+            "                                                                    multicast: done.");
+    }
+    pthread_cleanup_pop(1);
+  }
+  pthread_cleanup_pop(1); // will never happen
+  pthread_exit(NULL);
+}
+
+void metadata_multicast_queue_init() {
+    // create a pc_queue for the metadata_multicast_queue
+    pc_queue_init(&metadata_multicast_queue, (char *)&metadata_multicast_queue_items,
+                  sizeof(metadata_package), metadata_multicast_queue_size, "multicast");
+    if (named_pthread_create(&metadata_multicast_thread, NULL, metadata_multicast_thread_function,
+                             NULL, "metadata mcst") != 0)
+      debug(1, "Failed to create metadata multicast thread!");
+}
+
+void metadata_multicast_queue_stop() {
+  if (metadata_multicast_thread) {
+    pthread_cancel(metadata_multicast_thread);
+    pthread_join(metadata_multicast_thread, NULL);
+    pc_queue_delete(&metadata_multicast_queue);
+    // debug(2, "metadata stop multicast done.");
+  }
+}
@@ -0,0 +1,10 @@
+#pragma once
+
+#include <inttypes.h>
+#include "rtsp.h"
+
+void metadata_multicast_queue_init();
+void metadata_multicast_queue_stop();
+int send_metadata_to_multicast_queue(const uint32_t type, const uint32_t code,
+                           const char *data, const uint32_t length, rtsp_message *carrier,
+                           int block);
@@ -0,0 +1,172 @@
+/*
+ * Producer--consumer queue and access methods.
+ * This file is part of Shairport Sync.
+ * Copyright (c) Mike Brady 2017--2026
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include "pc_queue.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+void pc_queue_init(pc_queue *the_queue, char *items, size_t item_size, uint32_t number_of_items,
+                   const char *name) {
+  if (name)
+    debug(4, "Creating metadata queue \"%s\".", name);
+  else
+    debug(1, "Creating an unnamed metadata queue.");
+  pthread_mutex_init(&the_queue->pc_queue_lock, NULL);
+  pthread_cond_init(&the_queue->pc_queue_item_added_signal, NULL);
+  pthread_cond_init(&the_queue->pc_queue_item_removed_signal, NULL);
+  the_queue->item_size = item_size;
+  the_queue->items = items;
+  the_queue->count = 0;
+  the_queue->capacity = number_of_items;
+  the_queue->toq = 0;
+  the_queue->eoq = 0;
+  if (name == NULL)
+    the_queue->name = NULL;
+  else
+    the_queue->name = strdup(name);
+}
+
+void pc_queue_delete(pc_queue *the_queue) {
+  if (the_queue->name)
+    debug(2, "Deleting metadata queue \"%s\".", the_queue->name);
+  else
+    debug(1, "Deleting an unnamed metadata queue.");
+  if (the_queue->name != NULL)
+    free(the_queue->name);
+  // debug(2, "destroying pc_queue_item_removed_signal");
+  pthread_cond_destroy(&the_queue->pc_queue_item_removed_signal);
+  // debug(2, "destroying pc_queue_item_added_signal");
+  pthread_cond_destroy(&the_queue->pc_queue_item_added_signal);
+  // debug(2, "destroying pc_queue_lock");
+  pthread_mutex_destroy(&the_queue->pc_queue_lock);
+  // debug(2, "destroying signals and locks done");
+}
+
+void pc_queue_cleanup_handler(void *arg) {
+  // debug(1, "pc_queue_cleanup_handler called.");
+  pc_queue *the_queue = (pc_queue *)arg;
+  int rc = pthread_mutex_unlock(&the_queue->pc_queue_lock);
+  if (rc)
+    debug(1, "Error unlocking for pc_queue_add_item or pc_queue_get_item.");
+}
+
+int pc_queue_add_item(pc_queue *the_queue, const void *the_stuff, int block) {
+  int response = 0;
+  int rc;
+  if (the_queue) {
+    if (block == 0) {
+      rc = debug_mutex_lock(&the_queue->pc_queue_lock, 10000, 4);
+      if (rc == EBUSY)
+        return EBUSY;
+    } else
+      rc = debug_mutex_lock(&the_queue->pc_queue_lock, 50000, 4);
+    if (rc)
+      debug(1, "Error %d (\"%s\") locking for pc_queue_add_item. Block is %d.", rc, strerror(rc),
+            block);
+    pthread_cleanup_push(pc_queue_cleanup_handler, (void *)the_queue);
+    // leave this out if you want this to return if the queue is already full
+    // irrespective of the block flag.
+    /*
+                while (the_queue->count == the_queue->capacity) {
+                        rc = pthread_cond_wait(&the_queue->pc_queue_item_removed_signal,
+       &the_queue->pc_queue_lock); if (rc) debug(1, "Error waiting for item to be removed");
+                }
+                */
+    if (the_queue->count < the_queue->capacity) {
+      uint32_t i = the_queue->eoq;
+      void *p = the_queue->items + the_queue->item_size * i;
+      //    void * p = &the_queue->qbase + the_queue->item_size*the_queue->eoq;
+      memcpy(p, the_stuff, the_queue->item_size);
+
+      // update the pointer
+      i++;
+      if (i == the_queue->capacity)
+        // fold pointer if necessary
+        i = 0;
+      the_queue->eoq = i;
+      the_queue->count++;
+      // debug(2,"metadata queue+ \"%s\" %d/%d.", the_queue->name, the_queue->count,
+      // the_queue->capacity);
+      if (the_queue->count == the_queue->capacity)
+        debug(3, "metadata queue \"%s\": is now full with %d items in it!", the_queue->name,
+              the_queue->count);
+      rc = pthread_cond_signal(&the_queue->pc_queue_item_added_signal);
+      if (rc)
+        debug(1, "metadata queue \"%s\": error signalling after pc_queue_add_item",
+              the_queue->name);
+    } else {
+      response = EWOULDBLOCK; // a bit arbitrary, this.
+      debug(3,
+            "metadata queue \"%s\": is already full with %d items in it. Not adding this item to "
+            "the queue.",
+            the_queue->name, the_queue->count);
+    }
+    pthread_cleanup_pop(1); // unlock the queue lock.
+  } else {
+    debug(1, "Adding an item to a NULL queue");
+  }
+  return response;
+}
+
+int pc_queue_get_item(pc_queue *the_queue, void *the_stuff) {
+  int rc;
+  if (the_queue) {
+    rc = debug_mutex_lock(&the_queue->pc_queue_lock, 50000, 4);
+    if (rc)
+      debug(1, "metadata queue \"%s\": error locking for pc_queue_get_item", the_queue->name);
+    pthread_cleanup_push(pc_queue_cleanup_handler, (void *)the_queue);
+    while (the_queue->count == 0) {
+      rc = pthread_cond_wait(&the_queue->pc_queue_item_added_signal, &the_queue->pc_queue_lock);
+      if (rc)
+        debug(1, "metadata queue \"%s\": error waiting for item to be added", the_queue->name);
+    }
+    uint32_t i = the_queue->toq;
+    //    void * p = &the_queue->qbase + the_queue->item_size*the_queue->toq;
+    void *p = the_queue->items + the_queue->item_size * i;
+    memcpy(the_stuff, p, the_queue->item_size);
+
+    // update the pointer
+    i++;
+    if (i == the_queue->capacity)
+      // fold pointer if necessary
+      i = 0;
+    the_queue->toq = i;
+    the_queue->count--;
+    debug(4, "metadata queue- \"%s\" %d/%d.", the_queue->name, the_queue->count,
+          the_queue->capacity);
+    rc = pthread_cond_signal(&the_queue->pc_queue_item_removed_signal);
+    if (rc)
+      debug(1, "metadata queue \"%s\": error signalling after pc_queue_get_item", the_queue->name);
+    pthread_cleanup_pop(1); // unlock the queue lock.
+  } else {
+    debug(1, "Removing an item from a NULL queue");
+  }
+  return 0;
+}
+
@@ -0,0 +1,26 @@
+
+#pragma once
+
+#include "common.h"
+#include "config.h"
+#include <pthread.h>
+
+typedef struct {
+  pthread_mutex_t pc_queue_lock;
+  pthread_cond_t pc_queue_item_added_signal;
+  pthread_cond_t pc_queue_item_removed_signal;
+  char *name;
+  size_t item_size;  // number of bytes in each item
+  uint32_t count;    // number of items in the queue
+  uint32_t capacity; // maximum number of items
+  uint32_t toq;      // first item to take
+  uint32_t eoq;      // free space at end of queue
+  void *items;       // a pointer to where the items are actually stored
+} pc_queue;          // producer-consumer queue
+
+void pc_queue_init(pc_queue *the_queue, char *items, size_t item_size, uint32_t number_of_items,
+                   const char *name);
+
+void pc_queue_delete(pc_queue *the_queue);
+int pc_queue_add_item(pc_queue *the_queue, const void *the_stuff, int block);
+int pc_queue_get_item(pc_queue *the_queue, void *the_stuff);
@@ -0,0 +1,186 @@
+  #include "pipe.h"
+  #include "core.h"
+  #include "pc_queue.h"
+  
+  #include <stdlib.h>
+  #include <sys/stat.h>
+  #include <string.h>
+  #include <errno.h>
+
+static int fd = -1; // the pipe file descriptor
+  
+pc_queue metadata_queue;
+#define metadata_queue_size 500
+metadata_package metadata_queue_items[metadata_queue_size];
+pthread_t metadata_thread;
+
+void metadata_open(void) {
+  if (config.metadata_enabled == 0)
+    return;
+
+  size_t pl = strlen(config.metadata_pipename) + 1;
+
+  char *path = malloc(pl + 1);
+  snprintf(path, pl + 1, "%s", config.metadata_pipename);
+
+  fd = try_to_open_pipe_for_writing(path);
+  free(path);
+}
+
+static void metadata_close(void) {
+  if (fd < 0)
+    return;
+  close(fd);
+  fd = -1;
+}
+
+void metadata_process(uint32_t type, uint32_t code, char *data, uint32_t length) {
+  // debug(1, "Process metadata with type %x, code %x and length %u.", type, code, length);
+  int ret = 0;
+  // readers may go away and come back
+
+  if (fd < 0)
+    metadata_open();
+  if (fd < 0)
+    return;
+  char thestring[1024];
+  snprintf(thestring, 1024, "<item><type>%x</type><code>%x</code><length>%u</length>", type, code,
+           length);
+  // ret = non_blocking_write(fd, thestring, strlen(thestring));
+  ret = write(fd, thestring, strlen(thestring));
+  if (ret < 0) {
+    // debug(1,"metadata_process error %d exit 1",ret);
+    return;
+  }
+  if ((data != NULL) && (length > 0)) {
+    snprintf(thestring, 1024, "\n<data encoding=\"base64\">\n");
+    // ret = non_blocking_write(fd, thestring, strlen(thestring));
+    ret = write(fd, thestring, strlen(thestring));
+    if (ret < 0) {
+      // debug(1,"metadata_process error %d exit 2",ret);
+      return;
+    }
+    // here, we write the data in base64 form using our nice base64 encoder
+    // but, we break it into lines of 76 output characters, except for the last
+    // one.
+    // thus, we send groups of (76/4)*3 =  57 bytes to the encoder at a time
+    size_t remaining_count = length;
+    char *remaining_data = data;
+    // size_t towrite_count;
+    char outbuf[76];
+    while ((remaining_count) && (ret >= 0)) {
+      size_t towrite_count = remaining_count;
+      if (towrite_count > 57)
+        towrite_count = 57;
+      size_t outbuf_size = 76; // size of output buffer on entry, length of result on exit
+      if (base64_encode_so((unsigned char *)remaining_data, towrite_count, outbuf, &outbuf_size) ==
+          NULL)
+        debug(1, "Error encoding base64 data.");
+      // debug(1,"Remaining count: %d ret: %d, outbuf_size:
+      // %d.",remaining_count,ret,outbuf_size);
+      // ret = non_blocking_write(fd, outbuf, outbuf_size);
+      ret = write(fd, outbuf, outbuf_size);
+      if (ret < 0) {
+        // debug(1,"metadata_process error %d exit 3",ret);
+        return;
+      }
+      remaining_data += towrite_count;
+      remaining_count -= towrite_count;
+    }
+    snprintf(thestring, 1024, "</data>");
+    // ret = non_blocking_write(fd, thestring, strlen(thestring));
+    ret = write(fd, thestring, strlen(thestring));
+    if (ret < 0) {
+      // debug(1,"metadata_process error %d exit 4",ret);
+      return;
+    }
+  }
+  snprintf(thestring, 1024, "</item>\n");
+  // ret = non_blocking_write(fd, thestring, strlen(thestring));
+  ret = write(fd, thestring, strlen(thestring));
+  if (ret < 0) {
+    // debug(1,"metadata_process error %d exit 5",ret);
+    return;
+  }
+}
+
+void metadata_thread_cleanup_function(__attribute__((unused)) void *arg) {
+  // debug(2, "metadata_thread_cleanup_function called");
+  metadata_close();
+}
+
+void *metadata_thread_function(__attribute__((unused)) void *ignore) {
+  //  #include <syscall.h>
+  //  debug(1, "metadata_thread_function PID %d", syscall(SYS_gettid));
+  metadata_package pack;
+  pthread_cleanup_push(metadata_thread_cleanup_function, NULL);
+  while (1) {
+    pc_queue_get_item(&metadata_queue, &pack);
+    pthread_cleanup_push(metadata_pack_cleanup_function, (void *)&pack);
+    if (config.metadata_enabled) {
+      if (pack.carrier) {
+        debug(4, "     pipe: type %x, code %x, length %u, message %d.", pack.type, pack.code,
+              pack.length, pack.carrier->index_number);
+      } else {
+        debug(4, "     pipe: type %x, code %x, length %u.", pack.type, pack.code, pack.length);
+      }
+      metadata_process(pack.type, pack.code, pack.data, pack.length);
+      debug(4, "     pipe: done.");
+    }
+    pthread_cleanup_pop(1);
+  }
+  pthread_cleanup_pop(1); // will never happen
+  pthread_exit(NULL);
+}
+
+void metadata_pipe_queue_init() {
+  // create the metadata pipe, if necessary
+  size_t pl = strlen(config.metadata_pipename) + 1;
+  char *path = malloc(pl + 1);
+  snprintf(path, pl + 1, "%s", config.metadata_pipename);
+  mode_t oldumask = umask(000);
+  if (mkfifo(path, 0666) && errno != EEXIST)
+    die("Could not create metadata pipe \"%s\".", path);
+  umask(oldumask);
+  debug(1, "metadata pipe name is \"%s\".", path);
+
+  // try to open it
+  fd = try_to_open_pipe_for_writing(path);
+  // we check that it's not a "real" error. From the "man 2 open" page:
+  // "ENXIO  O_NONBLOCK | O_WRONLY is set, the named file is a FIFO, and no process has the FIFO
+  // open for reading." Which is okay.
+  if ((fd == -1) && (errno != ENXIO)) {
+    char errorstring[1024];
+    strerror_r(errno, (char *)errorstring, sizeof(errorstring));
+    debug(1, "metadata_init -- error %d (\"%s\") opening pipe: \"%s\".", errno,
+          (char *)errorstring, path);
+    warn("can not open metadata pipe -- error %d (\"%s\") opening pipe: \"%s\".", errno,
+         (char *)errorstring, path);
+  }
+  free(path);
+
+  // initialise the metadata queues first, otherwise the might be a race condition
+  // create a pc_queue for the metadata pipe
+  pc_queue_init(&metadata_queue, (char *)&metadata_queue_items, sizeof(metadata_package),
+                metadata_queue_size, "pipe");
+
+  if (named_pthread_create(&metadata_thread, NULL, metadata_thread_function, NULL,
+                           "metadata pipe") != 0)
+    debug(1, "Failed to create metadata thread!");
+}
+
+void metadata_pipe_queue_stop() {
+  if (metadata_thread) {
+    // debug(2, "metadata stop metadata_thread thread.");
+    pthread_cancel(metadata_thread);
+    pthread_join(metadata_thread, NULL);
+    pc_queue_delete(&metadata_queue);
+    // debug(2, "metadata_stop finished successfully.");
+  }
+}
+
+int send_metadata_to_pipe_queue(const uint32_t type, const uint32_t code,
+                           const char *data, const uint32_t length, rtsp_message *carrier,
+                           int block) {
+    return send_metadata_to_queue(&metadata_queue, type, code, data, length, carrier, block);
+}
@@ -0,0 +1,10 @@
+#pragma once
+
+#include <inttypes.h>
+#include "rtsp.h"
+
+void metadata_pipe_queue_init();
+void metadata_pipe_queue_stop();
+int send_metadata_to_pipe_queue(const uint32_t type, const uint32_t code,
+                           const char *data, const uint32_t length, rtsp_message *carrier,
+                           int block);
@@ -35,9 +35,11 @@

 #include "rtp.h"

+#ifdef CONFIG_DACP_CLIENT
 #include "dacp.h"
+#endif

-#include "metadata_hub.h"
+#include "metadata/hub.h"
 #include "mpris-service.h"

 static guint ownerID = 0;
@@ -240,28 +242,36 @@ static gboolean on_handle_quit(MediaPlayer2 *skeleton, GDBusMethodInvocation *in

 static gboolean on_handle_next(MediaPlayer2Player *skeleton, GDBusMethodInvocation *invocation,
                               __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("nextitem");
+#endif
  media_player2_player_complete_next(skeleton, invocation);
  return TRUE;
 }

 static gboolean on_handle_previous(MediaPlayer2Player *skeleton, GDBusMethodInvocation *invocation,
                                   __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("previtem");
+#endif
  media_player2_player_complete_previous(skeleton, invocation);
  return TRUE;
 }

 static gboolean on_handle_stop(MediaPlayer2Player *skeleton, GDBusMethodInvocation *invocation,
                               __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("stop");
+#endif
  media_player2_player_complete_stop(skeleton, invocation);
  return TRUE;
 }

 static gboolean on_handle_pause(MediaPlayer2Player *skeleton, GDBusMethodInvocation *invocation,
                                __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("pause");
+#endif
  media_player2_player_complete_pause(skeleton, invocation);
  return TRUE;
 }
@@ -269,14 +279,18 @@ static gboolean on_handle_pause(MediaPlayer2Player *skeleton, GDBusMethodInvocat
 static gboolean on_handle_play_pause(MediaPlayer2Player *skeleton,
                                     GDBusMethodInvocation *invocation,
                                     __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("playpause");
+#endif
  media_player2_player_complete_play_pause(skeleton, invocation);
  return TRUE;
 }

 static gboolean on_handle_play(MediaPlayer2Player *skeleton, GDBusMethodInvocation *invocation,
                               __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  send_simple_dacp_command("play");
+#endif
  media_player2_player_complete_play(skeleton, invocation);
  return TRUE;
 }
@@ -284,11 +298,13 @@ static gboolean on_handle_play(MediaPlayer2Player *skeleton, GDBusMethodInvocati
 static gboolean on_handle_set_volume(MediaPlayer2Player *skeleton,
                                     GDBusMethodInvocation *invocation, const gdouble volume,
                                     __attribute__((unused)) gpointer user_data) {
+#ifdef CONFIG_DACP_CLIENT
  double ap_volume = mpris_volume_to_airplay_volume(volume);
  debug(2, "Set mpris volume to %.6f, i.e. airplay volume to %.6f.", volume, ap_volume);
  char command[256] = "";
  snprintf(command, sizeof(command), "setproperty?dmcp.device-volume=%.6f", ap_volume);
  send_simple_dacp_command(command);
+#endif
  media_player2_player_complete_play(skeleton, invocation);
  return TRUE;
 }
@@ -11,10 +11,21 @@

 #include "rtp.h"

+#ifdef CONFIG_DACP_CLIENT
 #include "dacp.h"
-#include "metadata_hub.h"
+#endif
+#include "metadata/hub.h"
+#include "metadata/core.h"
+#include "metadata/pc_queue.h"
+
 #include "mqtt.h"
 #include <mosquitto.h>
+// this is for receiving metadata
+
+pc_queue metadata_mqtt_queue;
+#define metadata_mqtt_queue_size 500
+metadata_package metadata_mqtt_queue_items[metadata_mqtt_queue_size];
+pthread_t metadata_mqtt_thread;

 // this holds the mosquitto client
 struct mosquitto *global_mosq = NULL;
@@ -71,7 +82,9 @@ void on_message(__attribute__((unused)) struct mosquitto *mosq,
        release_play_lock(NULL); // stop any current session and don't replace it
      } else {
        debug(2, "[MQTT]: DACP Command: %s\n", commands[it]);
+#ifdef CONFIG_DACP_CLIENT
        send_simple_dacp_command(commands[it]);
+#endif
      }
      break;
    }
@@ -443,3 +456,62 @@ int initialise_mqtt() {

  return 0;
 }
+
+// metadata handling stuff
+void metadata_mqtt_close(void) {}
+
+void metadata_mqtt_thread_cleanup_function(__attribute__((unused)) void *arg) {
+  // debug(2, "metadata_mqtt_thread_cleanup_function called");
+  metadata_mqtt_close();
+  // debug(2, "metadata_mqtt_thread_cleanup_function done");
+}
+
+void *metadata_mqtt_thread_function(__attribute__((unused)) void *ignore) {
+  //  #include <syscall.h>
+  //  debug(1, "metadata_mqtt_thread_function PID %d", syscall(SYS_gettid));
+  metadata_package pack;
+  pthread_cleanup_push(metadata_mqtt_thread_cleanup_function, NULL);
+  while (1) {
+    pc_queue_get_item(&metadata_mqtt_queue, &pack);
+    pthread_cleanup_push(metadata_pack_cleanup_function, (void *)&pack);
+    if (config.mqtt_enabled) {
+      if (pack.carrier) {
+        debug(3,
+              "                                        mqtt: type %x, code %x, length %u, message "
+              "%d.",
+              pack.type, pack.code, pack.length, pack.carrier->index_number);
+      } else {
+        debug(3, "                                        mqtt: type %x, code %x, length %u.",
+              pack.type, pack.code, pack.length);
+      }
+      mqtt_process_metadata(pack.type, pack.code, pack.data, pack.length);
+      debug(3, "                                        mqtt: done.");
+    }
+
+    pthread_cleanup_pop(1);
+  }
+  pthread_cleanup_pop(1); // will never happen
+  pthread_exit(NULL);
+}
+
+void metadata_mqtt_queue_init() {
+  // create a pc_queue for the MQTT handler
+  pc_queue_init(&metadata_mqtt_queue, (char *)&metadata_mqtt_queue_items, sizeof(metadata_package),
+                metadata_mqtt_queue_size, "mqtt");
+  if (named_pthread_create(&metadata_mqtt_thread, NULL, metadata_mqtt_thread_function, NULL,
+                           "metadata mqtt") != 0)
+    debug(1, "Failed to create metadata mqtt thread!");
+}
+void metadata_mqtt_queue_stop() {
+    // debug(2, "metadata stop mqtt thread.");
+    pthread_cancel(metadata_mqtt_thread);
+    pthread_join(metadata_mqtt_thread, NULL);
+    pc_queue_delete(&metadata_mqtt_queue);
+    // debug(2, "metadata stop mqtt done.");
+}
+int send_metadata_to_mqtt_queue(const uint32_t type, const uint32_t code,
+                           const char *data, const uint32_t length, rtsp_message *carrier,
+                           int block) {
+    return send_metadata_to_queue(&metadata_mqtt_queue, type, code, data, length, carrier, block);
+}
+
@@ -12,4 +12,10 @@ void on_connect(struct mosquitto *mosq, void *userdata, int rc);
 void on_disconnect(struct mosquitto *mosq, void *userdata, int rc);
 void on_message(struct mosquitto *mosq, void *userdata, const struct mosquitto_message *msg);
 void _cb_log(struct mosquitto *mosq, void *userdata, int level, const char *str);
+
+void metadata_mqtt_queue_init();
+void metadata_mqtt_queue_stop();
+int send_metadata_to_mqtt_queue(const uint32_t type, const uint32_t code,
+                           const char *data, const uint32_t length, rtsp_message *carrier,
+                           int block);
 #endif /* #ifndef MQTT_H */
@@ -40,7 +40,7 @@
    <property name="ElapsedTime" type="b" access="readwrite" />
    <property name="DeltaTime" type="b" access="readwrite" />
    <property name="FileAndLine" type="b" access="readwrite" />
-  </interface>
+  </interface>  
  <interface name="org.gnome.ShairportSync.RemoteControl">
 		<method name='FastForward'/>
 		<method name='Rewind'/>
@@ -95,7 +95,7 @@ hash_init(enum hash_alg alg, HashCTX *c)
 }

 int
-hash_update(enum hash_alg alg, HashCTX *c, const void *data, size_t len)
+hash_update(__attribute__((unused)) enum hash_alg alg, HashCTX *c, const void *data, size_t len)
 {
 #if CONFIG_OPENSSL
  switch (alg)
@@ -593,7 +593,7 @@ encrypt_ctr(unsigned char *ciphertext, int ciphertext_len,
 /* -------------------------- IMPLEMENTATION -------------------------------- */

 static int
-client_setup_new(struct pair_setup_context *handle, const char *pin, pair_cb add_cb, void *cb_arg, const char *device_id)
+client_setup_new(struct pair_setup_context *handle, const char *pin, __attribute__((unused)) pair_cb add_cb, __attribute__((unused)) void *cb_arg, __attribute__((unused)) const char *device_id)
 {
  struct pair_client_setup_context *sctx = &handle->sctx.client;

@@ -853,7 +853,7 @@ client_setup_result(struct pair_setup_context *handle)
 {
  struct pair_client_setup_context *sctx = &handle->sctx.client;
  char *ptr;
-  int i;
+  unsigned int i;

  // Last 32 bytes of the private key is the public key, so we don't need to
  // explicitly export that
@@ -867,13 +867,13 @@ client_setup_result(struct pair_setup_context *handle)


 static int
-client_verify_new(struct pair_verify_context *handle, const char *client_setup_keys, pair_cb cb, void *cb_arg, const char *device_id)
+client_verify_new(struct pair_verify_context *handle, const char *client_setup_keys, __attribute__((unused)) pair_cb cb, __attribute__((unused)) void *cb_arg, const char *device_id)
 {
  struct pair_client_verify_context *vctx = &handle->vctx.client;
  char hex[] = { 0, 0, 0 };
  size_t hexkey_len;
  const char *ptr;
-  int i;
+  unsigned int i;

  if (!is_initialized())
    return -1;
@@ -1024,7 +1024,7 @@ client_verify_response1(struct pair_verify_context *handle, const uint8_t *data,
 }

 static int
-client_verify_response2(struct pair_verify_context *handle, const uint8_t *data, size_t data_len)
+client_verify_response2(struct pair_verify_context *handle, __attribute__((unused)) const uint8_t *data, __attribute__((unused)) size_t data_len)
 {
  struct pair_client_verify_context *vctx = &handle->vctx.client;
  // TODO actually check response
@@ -822,7 +822,7 @@ static void
 hexread(uint8_t *out, size_t out_len, const char *in)
 {
  char hex[] = { 0, 0, 0 };
-  int i;
+  unsigned int i;

  for (i = 0; i < out_len; i++, in+=2)
    {
@@ -1668,7 +1668,7 @@ static int
 client_setup_result(struct pair_setup_context *handle)
 {
  char *ptr;
-  int i;
+  unsigned int i;

  assert(sizeof(handle->result_str) >= 2 * sizeof(handle->result.client_private_key) + 2 * sizeof(handle->result.server_public_key) + 1);

@@ -1686,7 +1686,7 @@ client_setup_result(struct pair_setup_context *handle)
 }

 static int
-client_verify_new(struct pair_verify_context *handle, const char *client_setup_keys, pair_cb cb, void *cb_arg, const char *device_id)
+client_verify_new(struct pair_verify_context *handle, const char *client_setup_keys, __attribute__((unused)) pair_cb cb, __attribute__((unused)) void *cb_arg, __attribute__((unused)) const char *device_id)
 {
  struct pair_client_verify_context *vctx = &handle->vctx.client;
  size_t hexkey_len;
@@ -2888,7 +2888,7 @@ server_list_response(size_t *len, pair_list_cb cb, void *cb_arg)
 }

 static int
-server_list(uint8_t **out, size_t *out_len, pair_list_cb cb, void *cb_arg, const uint8_t *in, size_t in_len)
+server_list(uint8_t **out, size_t *out_len, pair_list_cb cb, void *cb_arg, __attribute__((unused)) const uint8_t *in, __attribute__((unused)) size_t in_len)
 {
  // Skip reading the request, it just has state = 1 and pair method =
  // PairingMethodListPairings
@@ -72,8 +72,12 @@
 #include <FFTConvolver/convolver.h>
 #endif

+#ifdef CONFIG_METADATA
+#include "metadata/core.h"
+#endif
+
 #ifdef CONFIG_METADATA_HUB
-#include "metadata_hub.h"
+#include "metadata/hub.h"
 #endif

 #ifdef CONFIG_DACP_CLIENT
@@ -383,18 +387,6 @@ const char *get_category_string(airplay_stream_c cat) {

 #ifdef CONFIG_FFMPEG

-static void avcodec_alloc_context3_cleanup_handler(void *arg) {
-  debug(3, "avcodec_alloc_context3_cleanup_handler");
-  AVCodecContext *codec_context = arg;
-  av_free(codec_context);
-}
-
-static void avcodec_open2_cleanup_handler(__attribute__((unused)) void *arg) {
-  debug(3, "avcodec_open2_cleanup_handler");
-  // AVCodecContext *codec_context = arg;
-  // avcodec_close(codec_context);
-}
-
 static void swr_alloc_cleanup_handler(void *arg) {
  debug(3, "swr_alloc_cleanup_handler");
  SwrContext **swr = arg;
@@ -407,25 +399,9 @@ static void av_packet_alloc_cleanup_handler(void *arg) {
  av_packet_free(pkt);
 }

-/*
-static void av_frame_alloc_cleanup_handler(void *arg) {
-  debug(3, "av_frame_alloc_cleanup_handler");
-  AVFrame **frame = arg;
-  av_frame_free(frame);
-}
-*/
-
 void clear_decoding_chain(rtsp_conn_info *conn) {
  if (conn->incoming_ssrc != 0) {
-    //    debug_mutex_lock(&conn->ab_mutex, 30000, 0);
-    //    ab_resync(conn);
-    //    debug_mutex_unlock(&conn->ab_mutex, 0);
-    pthread_cleanup_push(avcodec_alloc_context3_cleanup_handler, conn->codec_context);
-    pthread_cleanup_push(malloc_cleanup, &conn->codec_context->extradata);
-    pthread_cleanup_push(avcodec_open2_cleanup_handler, conn->codec_context);
-    pthread_cleanup_pop(1); // avcodec_open2_cleanup_handler
-    pthread_cleanup_pop(1); // deallocate the malloc
-    pthread_cleanup_pop(1); // avcodec_alloc_context3_cleanup_handler
+    avcodec_free_context(&conn->codec_context);
    conn->incoming_ssrc = SSRC_NONE;
  }
 }
@@ -776,6 +752,9 @@ int setup_software_resampler(rtsp_conn_info *conn, ssrc_t ssrc) {
    // get information about the output from the resampler
    int64_t resampler_output_format = 0;
    int resampler_channels_found = 0;
+    
+    int oldState;
+    pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState);

 #if LIBAVUTIL_VERSION_MAJOR >= 57

@@ -886,6 +865,8 @@ int setup_software_resampler(rtsp_conn_info *conn, ssrc_t ssrc) {
          free(device_channels);
        }
      }
+      
+      pthread_setcancelstate(oldState, NULL);

      if (output_channel_map_faulty != 0) {
        once(inform("The output device's %u-channel map is incomplete or faulty: \"%s\".",
@@ -1064,70 +1045,70 @@ void prepare_decoding_chain(rtsp_conn_info *conn, ssrc_t ssrc) {
        conn->codec = avcodec_find_decoder(AV_CODEC_ID_AAC);
        break;
      default:
-        die("Can't find a suitable codec for SSRC: %s", get_ssrc_name(ssrc));
+        die("Connection %d: can't find a suitable codec for SSRC: %s", conn->connection_number, get_ssrc_name(ssrc));
        break;
      }

+      int oldState;
+      pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState);
+
      // Get a decoder-dependent codec context
      conn->codec_context = avcodec_alloc_context3(conn->codec);
-      if (conn->codec_context == NULL) {
-        debug(1, "Could not allocate a codec context!");
-      }
-      // push a deallocator -- av_free(codec_context)
-      pthread_cleanup_push(avcodec_alloc_context3_cleanup_handler, conn->codec_context);
-
-      // prepare to open the codec context with that codec
-      // but first, if it's the ALAC decoder, prepare a magic cookie
-      if ((ssrc == ALAC_48000_S24_2) || (ssrc == ALAC_44100_S16_2)) {
-        alac_ffmpeg_magic_cookie *extradata =
-            malloc(sizeof(alac_ffmpeg_magic_cookie)); // might not use it
-        if (extradata == NULL)
-          die("Could not allocate memory for a magic cookie.");
-        // creata a magic cookie preceded by the 12-byte "atom" (?) expected by FFMPEG (?)
-        memset(extradata, 0, sizeof(alac_ffmpeg_magic_cookie));
-        extradata->cookie_size = htonl(sizeof(alac_ffmpeg_magic_cookie));
-        extradata->cookie_tag = htonl('alac');
-        extradata->alac_config.frameLength = htonl(352);
-        if (ssrc == ALAC_48000_S24_2) {
-          extradata->alac_config.bitDepth = 24; // Seems to be S24
-          extradata->alac_config.sampleRate = htonl(48000);
+        if (conn->codec_context != NULL) {
+        // push a deallocator -- av_free(codec_context)
+        // pthread_cleanup_push(avcodec_alloc_context3_cleanup_handler, &conn->codec_context);
+  
+        // prepare to open the codec context with that codec
+        // but first, if it's the ALAC decoder, prepare a magic cookie
+        if ((ssrc == ALAC_48000_S24_2) || (ssrc == ALAC_44100_S16_2)) {
+          alac_ffmpeg_magic_cookie *extradata =
+              malloc(sizeof(alac_ffmpeg_magic_cookie)); // might not use it
+          if (extradata == NULL)
+            die("connection %d: could not allocate memory for a magic cookie.", conn->connection_number);
+          // creata a magic cookie preceded by the 12-byte "atom" (?) expected by FFMPEG (?)
+          memset(extradata, 0, sizeof(alac_ffmpeg_magic_cookie));
+          extradata->cookie_size = htonl(sizeof(alac_ffmpeg_magic_cookie));
+          extradata->cookie_tag = htonl('alac');
+          extradata->alac_config.frameLength = htonl(352);
+          if (ssrc == ALAC_48000_S24_2) {
+            extradata->alac_config.bitDepth = 24; // Seems to be S24
+            extradata->alac_config.sampleRate = htonl(48000);
+          } else {
+            extradata->alac_config.bitDepth = 16; // Seems to be S16
+            extradata->alac_config.sampleRate = htonl(44100);
+          }
+          extradata->alac_config.pb = 40;
+          extradata->alac_config.mb = 10;
+          extradata->alac_config.kb = 14;
+          extradata->alac_config.numChannels = 2;
+          extradata->alac_config.maxRun = htons(255);
+          conn->codec_context->extradata = (uint8_t *)extradata;
+          conn->codec_context->extradata_size = sizeof(alac_ffmpeg_magic_cookie);
        } else {
-          extradata->alac_config.bitDepth = 16; // Seems to be S16
-          extradata->alac_config.sampleRate = htonl(44100);
+          conn->codec_context->extradata = NULL;
+        }
+        // pthread_cleanup_push(malloc_cleanup, &conn->codec_context->extradata);
+        // avcodec_free_context() will free extradata
+  
+        if (avcodec_open2(conn->codec_context, conn->codec, NULL) < 0) {
+            pthread_setcancelstate(oldState, NULL);
+            die("connection %d: could not initialise the codec context", conn->connection_number);
        }
-        extradata->alac_config.pb = 40;
-        extradata->alac_config.mb = 10;
-        extradata->alac_config.kb = 14;
-        extradata->alac_config.numChannels = 2;
-        extradata->alac_config.maxRun = htons(255);
-        conn->codec_context->extradata = (uint8_t *)extradata;
-        conn->codec_context->extradata_size = sizeof(alac_ffmpeg_magic_cookie);
      } else {
-        conn->codec_context->extradata = NULL;
-      }
-      pthread_cleanup_push(malloc_cleanup, &conn->codec_context->extradata);
-
-      if (avcodec_open2(conn->codec_context, conn->codec, NULL) < 0) {
-        die("Could not initialise the codec context");
-      }
-
-      // push a closer -- avcodec_close(codec_context);
-      pthread_cleanup_push(avcodec_open2_cleanup_handler, conn->codec_context);
+        die("connection %d: could not allocate a codec context!", conn->connection_number);
+      }      
+      pthread_setcancelstate(oldState, NULL);

      conn->input_rate = get_ssrc_rate(ssrc);
+      debug(2, "Connection %d: set conn->input_rate: %u.", conn->connection_number, conn->input_rate);
      if ((ssrc == ALAC_48000_S24_2) || (ssrc == ALAC_44100_S16_2)) {
        conn->frames_per_packet = 352;
      } else {
        conn->frames_per_packet = 1024;
      }
-
      conn->codec_context->sample_rate = conn->input_rate;
-
      conn->ffmpeg_decoding_chain_initialised = 1;
-      pthread_cleanup_pop(0); // successful exit -- don't run the avcodec_open2_cleanup_handler
-      pthread_cleanup_pop(0); // successful exit -- don't deallocate the malloc
-      pthread_cleanup_pop(
-          0); // successful exit -- don't run the avcodec_alloc_context3_cleanup_handler
+      conn->input_format_is_valid = 1;
    }
  }
 }
@@ -1142,6 +1123,9 @@ int64_t avframe_to_audio(rtsp_conn_info *conn, AVFrame *decoded_frame, uint8_t *
  uint8_t *pcm_audio = NULL;
  int dst_linesize;

+  int oldState;
+  pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
+
  int number_of_output_samples_expected = swr_get_out_samples(conn->swr, decoded_frame->nb_samples);

  debug(4, "A maximum of %d output samples expected for %d input samples.",
@@ -1243,10 +1227,12 @@ int64_t avframe_to_audio(rtsp_conn_info *conn, AVFrame *decoded_frame, uint8_t *
    *decoded_audio_samples_count = 0;
  }
  av_freep(&pcm_audio);
-  return swr_get_delay(
+  int64_t response = swr_get_delay(
      conn->swr,
      RATE_FROM_ENCODED_FORMAT(
          config.current_output_configuration)); // number of frames left in the resampler
+  pthread_setcancelstate(oldState, NULL);
+  return response;
 }

 // take a block of incoming data and decode it.
@@ -1254,8 +1240,11 @@ int64_t avframe_to_audio(rtsp_conn_info *conn, AVFrame *decoded_frame, uint8_t *
 // transcoded and maybe resampled later
 AVFrame *block_to_avframe(rtsp_conn_info *conn, uint8_t *incoming_data,
                          size_t incoming_data_length) {
+
  AVFrame *decoded_frame = NULL;
  if (incoming_data_length > 8) {
+    int oldState;
+    pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
    AVPacket *pkt = av_packet_alloc();
    if (pkt) {
      // push a deallocator -- av_packet_free(pkt);
@@ -1314,6 +1303,7 @@ AVFrame *block_to_avframe(rtsp_conn_info *conn, uint8_t *incoming_data,
    } else {
      debug(1, "Can't allocate an AVPacket!");
    }
+    pthread_setcancelstate(oldState, NULL);
  }
  return decoded_frame;
 }
@@ -2032,7 +2022,7 @@ static abuf_t *buffer_get_frame(rtsp_conn_info *conn, int resync_requested) {
  do {
    // debug(3, "buffer_get_frame is iterating");
    // we must have timing information before we can do anything here
-    if (have_timestamp_timing_information(conn)) {
+    if ((have_timestamp_timing_information(conn)) && (conn->input_format_is_valid != 0)) {

      int rco = get_requested_connection_state_to_output();

@@ -2481,10 +2471,12 @@ static abuf_t *buffer_get_frame(rtsp_conn_info *conn, int resync_requested) {
                             RATE_FROM_ENCODED_FORMAT(config.current_output_configuration)) /
                            1000000000;
                        int64_t exact_frame_gap = gross_frame_gap - dac_delay;
-                        debug(3,
+      
+
+                        debug(4,
                              "Exact frame gap: %" PRId64
-                              ". DAC delay: %ld. First packet timestamp: %u.",
-                              exact_frame_gap, dac_delay, conn->first_packet_timestamp);
+                              ". DAC delay: %ld. Total: %" PRId64 ". First packet timestamp: %u. ",
+                              exact_frame_gap, dac_delay, gross_frame_gap, conn->first_packet_timestamp);
                        // int64_t frames_needed_to_maintain_desired_buffer =
                        //     (int64_t)(config.audio_backend_buffer_desired_length *
                        //               config.current_output_configuration->rate) -
@@ -2687,7 +2679,7 @@ static abuf_t *buffer_get_frame(rtsp_conn_info *conn, int resync_requested) {
        // wait if the buffer is empty
        if ((conn->ab_synced != 0) && (conn->ab_read == conn->ab_write)) { // the buffer is empty!
          if (notified_buffer_empty == 0) {
-            debug(2, "Connection %d: Buffer Empty", conn->connection_number);
+            debug(4, "Connection %d: Buffer Empty", conn->connection_number);
            notified_buffer_empty = 1;
            // reset_input_flow_metrics(conn); // don't do a full flush parameters reset
            // conn->initial_reference_time = 0;
@@ -2701,14 +2693,10 @@ static abuf_t *buffer_get_frame(rtsp_conn_info *conn, int resync_requested) {
      wait = 1; // keep waiting until the timing information becomes available
    }
    if (wait) {
-      if (conn->frames_per_packet == 0)
-        debug(1, "frames_per_packet is zero!");
-
-      uint64_t time_to_wait_for_wakeup_ns = 20000000; // default if no input rate is set
-      if (conn->input_rate != 0) {
-        time_to_wait_for_wakeup_ns =
-            1000000000 / conn->input_rate; // this is time period of one frame
-        time_to_wait_for_wakeup_ns *= 4 * conn->frames_per_packet;
+      uint64_t time_to_wait_for_wakeup_ns = 10000000; // default
+      if (conn->input_format_is_valid != 0) {      
+        time_to_wait_for_wakeup_ns = 1000000000 / conn->input_rate; // this is time period of one frame
+        time_to_wait_for_wakeup_ns *= 4 * conn->frames_per_packet; // about 4 * 7 mS for 352 frames per second
      }

 #ifdef COMPILE_FOR_LINUX_AND_FREEBSD_AND_CYGWIN_AND_OPENBSD
@@ -2719,12 +2707,13 @@ static abuf_t *buffer_get_frame(rtsp_conn_info *conn, int resync_requested) {
      struct timespec time_of_wakeup;
      time_of_wakeup.tv_sec = sec;
      time_of_wakeup.tv_nsec = nsec;
-
+      // debug(1, "wait for up to %f mS or for the next packet...", time_to_wait_for_wakeup_ns * 1E-6);
      int rc = pthread_cond_timedwait(&conn->flowcontrol, &conn->ab_mutex,
                                      &time_of_wakeup); // this is a pthread cancellation point
      if ((rc != 0) && (rc != ETIMEDOUT))
        // if (rc)
        debug(3, "pthread_cond_timedwait returned error code %d.", rc);
+      // debug(1, "waited");      
 #endif
 #ifdef COMPILE_FOR_OSX
      uint64_t sec = time_to_wait_for_wakeup_ns / 1000000000;
@@ -2804,12 +2793,15 @@ static abuf_t *buffer_get_frame(rtsp_conn_info *conn, int resync_requested) {
          debug(1, "error %d", ret);
        // We need to get those frames of silence out of the resampler
        // so we'll pass in an empty AVFrame to flush them through
-        AVFrame *avf = av_frame_alloc(); // empty frame
+        int oldState;
+        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState);
+        AVFrame *avf = av_frame_alloc();
        conn->frames_retained_in_the_resampler =
            avframe_to_audio(conn, avf, &pp, &pl, &number_of_output_frames);
+        av_frame_free(&avf);
+        pthread_setcancelstate(oldState, NULL);
        curframe->data = (short *)pp;
        curframe->length = number_of_output_frames;
-        av_frame_free(&avf);
      }
    }
 #ifndef CONFIG_AIRPLAY_2
@@ -5262,7 +5254,7 @@ int player_stop(rtsp_conn_info *conn) {
  // note -- this may be called from another connection thread.
  debug(2, "Connection %d: player_stop.", conn->connection_number);
  int response = 0; // okay
-  pthread_cleanup_debug_mutex_lock(&conn->player_create_delete_mutex, 5000, 1);
+  pthread_cleanup_debug_mutex_lock(&conn->player_create_delete_mutex, 5000, 4);
  pthread_t *pt = conn->player_thread;
  if (pt) {
    debug(3, "player_thread cancel...");
@@ -257,6 +257,7 @@ typedef struct {
 typedef struct {
  int connection_number;           // for debug ID purposes, nothing else...
  int is_playing;                  // set true by player_play, set false by player_stop
+  int input_format_is_valid;       // set when the input format is known and set in this structure
  unsigned int sync_samples_index; // for estimating the gap between the highest and lowest timing
                                   // error over the past n samples
  unsigned int sync_samples_count; // the array of samples is defined locally
@@ -272,7 +273,7 @@ typedef struct {
                             // otherwise
  int software_mute_enabled; // if we don't have a real mute that we can use
  int fd;
-  int authorized;   // set if a password is required and has been supplied
+  int authorized;   // set if a password is required and has been supplied or not required. Also always set in AirPlay 2 mode.
  char *auth_nonce; // the session nonce, if needed
  stream_cfg stream;
  SOCKADDR remote, local;
@@ -412,6 +413,7 @@ typedef struct {
                               // (will be unspecified if not build for AirPlay 2)

 #ifdef CONFIG_AIRPLAY_2
+  plist_t sessionPlist;
  char *airplay_gid; // UUID in the Bonjour advertisement -- if NULL, the group UUID is the same as
                     // the pi UUID
  airplay_t airplay_type; // are we using AirPlay 1 or AirPlay 2 protocol on this connection?
@@ -423,6 +425,8 @@ typedef struct {
  pthread_t rtp_ap2_control_thread;
  pthread_t rtp_realtime_audio_thread;
  pthread_t rtp_buffered_audio_thread;
+  pthread_mutex_t event_sender_mutex;
+  int event_channel_fd; // zero if closed, controlled by event_sender_mutex

  int ap2_event_receiver_exited;

@@ -1513,9 +1513,12 @@ int frame_to_ptp_local_time(uint32_t timestamp, uint64_t *time, rtsp_conn_info *
    int32_t frame_difference = timestamp - anchor_rtptime;
    int64_t time_difference = frame_difference;
    time_difference = time_difference * 1000000000;
-    if (conn->input_rate == 0)
-      die("conn->input_rate is zero!");
-    time_difference = time_difference / conn->input_rate;
+    if (conn->input_rate == 0) {
+      debug(1,"Connection %d: in a call to frame_to_ptp_local_time, conn->input_rate is zero!", conn->connection_number);
+      time_difference = 0;
+    } else {
+      time_difference = time_difference / conn->input_rate;
+    }
    uint64_t ltime = anchor_local_time + time_difference;
    *time = ltime;
    result = 0;
@@ -3,6 +3,27 @@

 #include "player.h"

+typedef struct {
+  int index_number;
+  uint32_t referenceCount; // we might start using this...
+  unsigned int nheaders;
+  char *name[16];
+  char *value[16];
+
+  uint32_t contentlength;
+  char *content;
+
+  // for requests
+  char method[16];
+  char path[256];
+
+  // for responses
+  int respcode;
+} rtsp_message;
+
+void msg_retain(rtsp_message *msg);
+void msg_free(rtsp_message **msgh);
+
 extern pthread_rwlock_t principal_conn_lock;
 extern rtsp_conn_info *principal_conn;
 extern rtsp_conn_info **conns;
@@ -27,19 +48,6 @@ play_lock_r get_play_lock(rtsp_conn_info *conn, int allow_session_interruption);
 // this will release the play lock only if the conn has it or if the conn is NULL
 void release_play_lock(rtsp_conn_info *conn);

-// initialise and completely delete the metadata stuff
-
-void metadata_init(void);
-void metadata_stop(void);
-
-// sends metadata out to the metadata pipe, if enabled.
-// It is sent with the type 'ssnc' the given code, data and length
-// The handler at the other end must know what to do with the data
-// e.g. if it's malloced, to free it, etc.
-// nothing is done automatically
-
-int send_ssnc_metadata(const uint32_t code, const char *data, const uint32_t length,
-                       const int block);

 #ifdef CONFIG_AIRPLAY_2
 ssize_t read_encrypted(int fd, pair_cipher_bundle *ctx, void *buf, size_t count);
@@ -14,7 +14,7 @@ general =
 //				%v for the version number, e.g. 3.0 and
 //				%V for the full version string, e.g. 3.3-OpenSSL-Avahi-ALSA-soxr-metadata-sysconfdir:/etc
 //		Overall length can not exceed 50 characters. Example: "Shairport Sync %v on %H".
-//	password = "secret"; // (AirPlay 1 only) leave this commented out if you don't want to require a password
+//	password = "secret"; // leave this commented out if you don't want to require a password
 //	The interpolation setting below controls how Shairport Sync adds or removes frames of audio to keep in sync.
 //			"auto" (default) measures the processor's floating point speed and chooses "soxr" if available and it is fast enough. Otherwise, "vernier" is selected.
 //			"soxr" uses the SoX library to recode a packet of frames to a new packet containing more or fewer frames. This needs a processor with fast floating point capability.
@@ -54,6 +54,9 @@
 #include <libavcodec/avcodec.h>
 #include <sodium.h>
 #include <uuid/uuid.h>
+#include "utilities/generate_random_uuid.h"
+#include "utilities/generate_device_uuid.h"
+
 #endif

 #ifdef CONFIG_MBEDTLS
@@ -84,8 +87,12 @@
 #include "dacp.h"
 #endif

+#if defined(CONFIG_METADATA)
+#include "metadata/core.h"
+#endif
+
 #if defined(CONFIG_METADATA_HUB)
-#include "metadata_hub.h"
+#include "metadata/hub.h"
 #endif

 #ifdef CONFIG_DBUS_INTERFACE
@@ -195,13 +202,12 @@ int has_fltp_capable_aac_decoder(void) {
 #endif

 #ifdef CONFIG_SOXR
-pthread_t soxr_time_check_thread;
-int soxr_time_check_thread_started = 0;
+pthread_t *soxr_time_check_thread = NULL;
 void *soxr_time_check(__attribute__((unused)) void *arg) {
  // this just checks how long it takes to process adding and subtracing a frame
  // from a buffer at 44100
-  //  #include <syscall.h>
-  //  debug(1, "soxr_time_check PID %d", syscall(SYS_gettid));
+  // #include <syscall.h>
+  // debug(1, "soxr_time_check PID %ld", syscall(SYS_gettid));

  const int buffer_length = 352;
  int32_t inbuffer[buffer_length * 2];
@@ -221,7 +227,7 @@ void *soxr_time_check(__attribute__((unused)) void *arg) {
      (uint64_t)1500000000 + soxr_start_time; // loop for a second and a half, max -- no need to be
                                              // able to cancel it, do _don't even try_!
  while (get_absolute_time_in_ns() < loop_until_time) {
-
+    pthread_testcancel();
    number_of_iterations++;
    for (i = 0; i < buffer_length; i++) {
      double w = sin(i * (frequency + number_of_iterations * 2) * 2 * M_PI / 44100);
@@ -230,6 +236,9 @@ void *soxr_time_check(__attribute__((unused)) void *arg) {
      inbuffer[i * 2 + 1] = wint;
    }

+    int oldState;
+    pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
+
    soxr_io_spec_t io_spec;
    io_spec.itype = SOXR_INT32_I;
    io_spec.otype = SOXR_INT32_I;
@@ -256,6 +265,8 @@ void *soxr_time_check(__attribute__((unused)) void *arg) {
                 outbuffer, buffer_length - 1, &odone, // Output.
                 &io_spec,                             // Input, output and transfer spec.
                 NULL, NULL);                          // Default configuration.
+    
+    pthread_setcancelstate(oldState, NULL);
  }

  int64_t soxr_execution_time =
@@ -271,8 +282,8 @@ void *soxr_time_check(__attribute__((unused)) void *arg) {
    debug(1, "No soxr-timing iterations performed, so \"vernier\" iteration will be used.");
    config.soxr_delay_index = 0; // used as a flag
  }
-  debug(2, "soxr_delay: %d nanoseconds, soxr_delay_threshold: %d milliseconds.",
-        config.soxr_delay_index, config.soxr_delay_threshold / 1000000);
+  debug(2, "soxr_delay maximum permissible: %d milliseconds, actual: %f milliseconds.",
+        config.soxr_delay_threshold / 1000000, 1E-6 * config.soxr_delay_index);
  if ((config.packet_stuffing == ST_soxr) &&
      (config.soxr_delay_index > config.soxr_delay_threshold))
    inform("Note: this device may be too slow for \"soxr\" interpolation. Consider choosing the "
@@ -337,6 +348,7 @@ void usage(char *progname) {
    printf("    -t, --timeout=SECONDS   Go back to idle mode from play mode after a break in communications of this many seconds (default 60). Set to 0 never to exit play mode.\n");
    printf("    --tolerance=TOLERANCE   [Deprecated] Allow a synchronization error of TOLERANCE frames (default 88) before trying to correct it.\n");
    printf("    --logOutputLevel        Log the output level setting -- a debugging option, useful for determining the optimum maximum volume.\n");
+
 #ifdef CONFIG_LIBDAEMON
    printf("    -d, --daemon            Daemonise.\n");
    printf("    -j, --justDaemoniseNoPIDFile            Daemonise without a PID file.\n");
@@ -347,6 +359,10 @@ void usage(char *progname) {
    printf("    --metadata-pipename=PIPE send metadata to PIPE, e.g. --metadata-pipename=/tmp/%s-metadata.\n", config.appName);
    printf("                            The default is /tmp/%s-metadata.\n", config.appName);
    printf("    -g, --get-coverart      Include cover art in the metadata to be gathered and sent.\n");
+#endif
+#if defined(CONFIG_DBUS_INTERFACE) || defined(CONFIG_MPRIS_INTERFACE)
+    printf("    --dbus-default-message-bus=BUS Use the BUS specified for the native D-Bus and MPRIS interfaces.\n");
+    printf("                            BUS must be \"system\" (default) or \"session\".\n");
 #endif
    printf("    --log-to-syslog         Send debug and statistics information through syslog\n");
    printf("                            If used, this should be the first command line argument.\n");
@@ -535,6 +551,7 @@ int parse_options(int argc, char **argv) {
  // for unexpected circumstances

  config.model = strdup("ShairportSync");
+  //config.model = strdup("AirPort10,115");
  // config.model = strdup("AudioAccessory5,1");

  // config.srcvers = strdup(PACKAGE_VERSION);
@@ -553,6 +570,9 @@ int parse_options(int argc, char **argv) {
 #endif
    config.firmware_version = strdup(PACKAGE_VERSION);

+  free(config.firmware_version);
+  config.firmware_version = strdup("5.2");
+
 #ifdef CONFIG_METADATA
  /* Get the metadata setting. */
  config.metadata_enabled = 1; // if metadata support is included, then enable it by default
@@ -581,83 +601,6 @@ int parse_options(int argc, char **argv) {
  // not made active again (not used)
 #endif

-#ifdef CONFIG_AIRPLAY_2
-  // the features code is a 64-bit number, but in the mDNS advertisement, the least significant 32
-  // bit are given first for example, if the features number is 0x1C340405F4A00, it will be given as
-  // features=0x405F4A00,0x1C340 in the mDNS string, and in a signed decimal number in the plist:
-  // 496155702020608 this setting here is the source of both the plist features response and the
-  // mDNS string.
-  // note: 0x300401F4A00 works but with weird delays and stuff
-  // config.airplay_features = 0x1C340405FCA00;
-  uint64_t mask =
-      ((uint64_t)1 << 17) | ((uint64_t)1 << 16) | ((uint64_t)1 << 15) | ((uint64_t)1 << 50);
-  config.airplay_features =
-      // 0x114BD04A5FCA00 & (~mask);
-      0x1C340405D4A00 & (~mask); // APX + Authentication4 (b14) with no metadata (see below)
-
-  /*
-    config.airplay_features |= (uint64_t)1 << 21; // Audio Format 4
-
-    config.airplay_features |= (uint64_t)1 << 25; // Unknown
-    config.airplay_features |= (uint64_t)1 << 36; // Unknown
-    config.airplay_features |= (uint64_t)1 << 39; // Unknown
-    config.airplay_features |= (uint64_t)1 << 43; // Supports System Pairing
-    config.airplay_features |= (uint64_t)1 << 47; // Unknown
-
-    // 0xB
-    config.airplay_features |= (uint64_t)1 << 63; // Unknown
-    config.airplay_features |= (uint64_t)1 << 61; // Unknown
-    config.airplay_features |= (uint64_t)1 << 60; // Unknown
-    // ...0xC
-    // // config.airplay_features |= (uint64_t)1 << 59; // Unknown
-    config.airplay_features |= (uint64_t)1 << 58; // Unknown
-
-    // ...0x3
-    config.airplay_features |= (uint64_t)1 << 53; // Unknown
-    config.airplay_features |= (uint64_t)1 << 52; // Unknown
-  */
-
-  // config.airplay_features |= ((uint64_t)1 << 58) | ((uint64_t)1 << 60) | ((uint64_t)1 << 58);
-
-  // 60 seems to interfere with disconnecting from a group
-
-  // Advertised with mDNS and returned with GET /info, see
-  // https://openairplay.github.io/airplay-spec/status_flags.html 0x4: Audio cable attached, no PIN
-  // required (transient pairing), 0x204: Audio cable attached, OneTimePairingRequired 0x604: Audio
-  // cable attached, OneTimePairingRequired, device was setup for Homekit access control
-  config.airplay_statusflags = 0;
-  config.airplay_statusflags |= 1 << 2; // Audio cable is attached
-  // config.airplay_statusflags |= 1 << 10; // DeviceWasSetupForHKAccessControl
-  // config.airplay_statusflags |= 1 << 11; // DeviceSupportsRelay
-  // config.airplay_statusflags |= 1 << 19; // Unknown. Seems to control whether individual volume
-  // controls are shown and whether the SPS devices shows when its active.
-
-  // Set to NULL to work with transient pairing
-  config.airplay_pin = NULL;
-
-  // use the MAC address placed in config.hw_addr to generate the default airplay_device_id
-  uint64_t temporary_airplay_id = nctoh64(config.hw_addr);
-  temporary_airplay_id =
-      temporary_airplay_id >> 16; // we only use the first 6 bytes but have imported 8.
-
-  // now generate a UUID
-  // from https://stackoverflow.com/questions/51053568/generating-a-random-uuid-in-c
-  // with thanks
-  uuid_t binuuid;
-  uuid_generate_random(binuuid);
-
-  char *uuid = malloc(UUID_STR_LEN + 1); // leave space for the NUL at the end
-  // Produces a UUID string at uuid consisting of lower-case letters
-  uuid_unparse_lower(binuuid, uuid);
-  config.airplay_pi = uuid;
-
-  char *pgid_uuid = malloc(UUID_STR_LEN + 1); // leave space for the NUL at the end
-  uuid_generate_random(binuuid);
-  uuid_unparse_lower(binuuid, pgid_uuid);
-  config.airplay_pgid = pgid_uuid;
-
-#endif
-
  // config_setting_t *setting;
  const char *str = NULL;
  int value = 0;
@@ -665,6 +608,11 @@ int parse_options(int argc, char **argv) {

  // debug(1, "Looking for the configuration file \"%s\".", config.configfile);

+  // use the MAC address placed in config.hw_addr to generate the default airplay_device_id
+  uint64_t temporary_airplay_id = nctoh64(config.hw_addr);
+  temporary_airplay_id =
+    temporary_airplay_id >> 16; // we only use the first 6 bytes but have imported 8.
+  
  config_init(&config_file_stuff);

  config_file_real_path = realpath(config.configfile, NULL);
@@ -1465,7 +1413,6 @@ int parse_options(int argc, char **argv) {
          "avahi enabled, or disable remote control.");
    }
 #endif
-#endif

 #ifdef CONFIG_AIRPLAY_2
    long long aid;
@@ -1481,6 +1428,8 @@ int parse_options(int argc, char **argv) {
    }

 #endif
+#endif
+
  }

  // now, do the command line options again, but this time do them fully -- it's a unix convention
@@ -1600,7 +1549,10 @@ int parse_options(int argc, char **argv) {
  // a uuid_t and an md5 hash are both 128 bits, 16 bytes
  uuid_t result;
  memset(result, 0, sizeof(result));
-  memcpy(result, config.ap1_prefix, sizeof(result));
+  if (sizeof(config.ap1_prefix) < sizeof(result))
+    memcpy(result, config.ap1_prefix, sizeof(config.ap1_prefix));
+  else
+    memcpy(result, config.ap1_prefix, sizeof(result));

  // OpenSSL is mandatory for AirPlay 2 anyway
 #ifdef CONFIG_OPENSSL
@@ -1627,8 +1579,8 @@ int parse_options(int argc, char **argv) {
  // Produces a UUID string at uuid consisting of lower-case letters
  uuid_unparse_lower(result, psi_uuid);
  config.airplay_psi = psi_uuid;
+  
  debug(3, "size of pk is %zu.", sizeof(config.airplay_pk));
-
  pair_public_key_get(PAIR_SERVER_HOMEKIT, config.airplay_pk, config.airplay_device_id);
  char buf[128];
  char *ptr = buf;
@@ -1637,18 +1589,38 @@ int parse_options(int argc, char **argv) {
    ptr += sprintf(ptr, "%02x", config.airplay_pk[pk_index]);
  *ptr = '\0';
  config.pk_string = strdup(buf);
+  
+  // the features code is a 64-bit number, but in the mDNS advertisement, the least significant 32
+  // bit are given first for example, if the features number is 0x1C340405F4A00, it will be given as
+  // features=0x405F4A00,0x1C340 in the mDNS string, and in a signed decimal number in the plist:
+  // 496155702020608 this setting here is the source of both the plist features response and the
+  // mDNS string.
+
+  config.airplay_features =
+       0x00018340405C4A00; // no AP2 metadata (b50), no AP1 text (b17), no AP1 progress (b16), no AP1 artwork (b15)
+  //     0x0001C340405C4A00; // no AP2 metadata (b50), no AP1 text (b17), no AP1 progress (b16), no AP1 artwork (b15)
+  //     0x0001C340445D0A00;
+  // config.airplay_features |= (1 << 26); // 0x0x4000000
+
+  // features=0x0001C340445D0A00 -- AirPort Express 

 #ifdef CONFIG_METADATA
  // If we are asking for metadata, turn on the relevant bits
-  if (config.metadata_enabled != 0) {
-    config.airplay_features |= (uint64_t)1 << 16; // progress, 17 is text, 50 is in a binary plist
-    config.airplay_features |= (uint64_t)1 << 17; // text, 50 is in a binary plist
-    // config.airplay_features |=
-    //  (uint64_t)1 << 50; // binary plist
+  
+  // If bit 50 is set, metadata is sent via plists in POST /command payloads.
+  // The data consists of textual information about what is playing and cover art
+  // It does not seem possible to turn off the cover art.

-    // If we are asking for artwork, turn on the relevant bit
-    if (config.get_coverart)
-      config.airplay_features |= (uint64_t)1 << 15; // artwork
+  // While bit 50 is set, no data comes through the "classic" way. That is
+  // no progress, text or picture data comes through in the way that
+  // it comes through in Classic AirPlay (aka AirPlay 1).
+  
+  // Although it is less flexible about what metadata is sent, bit 50 being set
+  // provides much more information, so should be the default for AirPlay 2
+  
+  if (config.metadata_enabled != 0) {
+    config.airplay_features |= (uint64_t)1 << 50; // metadata in a binary plist, including more state information    
+    // config.airplay_features |= ((uint64_t)1 << 15) | ((uint64_t)1 << 16) | ((uint64_t)1 << 17); // older metadata flags artwork, progress and text respectively
  }
 #endif

@@ -1669,6 +1641,23 @@ int parse_options(int argc, char **argv) {
  if (padding)
    *padding = 0;
  debug(2, "airplay_fex is \"%s\"", config.airplay_fex);
+  
+  // now the status flags
+  // Advertised with mDNS and returned with GET /info, see
+  // https://openairplay.github.io/airplay-spec/status_flags.html
+  
+  config.airplay_statusflags = 0;
+  config.airplay_statusflags |= 1 << 2; // Audio cable is attached
+  if (config.password != NULL) {
+    config.airplay_statusflags |= 1 << 7; // Password required
+  }
+  // config.airplay_statusflags |= 1 << 10; // DeviceWasSetupForHKAccessControl
+  // config.airplay_statusflags |= 1 << 11; // DeviceSupportsRelay
+  // config.airplay_statusflags |= 1 << 19; // Unknown. Seems to control whether individual volume
+  // controls are shown and whether the SPS devices shows when its active.
+
+  config.airplay_pi = generate_device_uuid(config.airplay_device_id);
+  config.airplay_pgid = generate_random_uuid();
 #endif

 #ifdef CONFIG_LIBDAEMON
@@ -1856,7 +1845,6 @@ void exit_function() {
        (config.daemonise == 0)) { // if this is the daemon process that is exiting or it's not
                                   // actually daemonised at all
 #endif
-      debug(2, "exit function called...");
      /*
      Actually, there is no terminate_mqtt() function.
      #ifdef CONFIG_MQTT
@@ -1902,12 +1890,16 @@ void exit_function() {
      }

 #ifdef CONFIG_SOXR
-      // be careful -- not sure if the thread can be cancelled cleanly, so wait for it to shut down
-      if (soxr_time_check_thread_started != 0) {
-        debug(2, "Waiting for SoXr timecheck to terminate...");
-        pthread_join(soxr_time_check_thread, NULL);
-        soxr_time_check_thread_started = 0;
-        debug(2, "Waiting for SoXr timecheck to terminate done");
+      {
+        int oldState;
+        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
+        if (soxr_time_check_thread != NULL) {
+          pthread_cancel(*soxr_time_check_thread);
+          pthread_join(*soxr_time_check_thread, NULL);
+          free(soxr_time_check_thread);
+          soxr_time_check_thread = NULL;
+        }
+        pthread_setcancelstate(oldState, NULL);
      }

 #endif
@@ -1948,8 +1940,6 @@ void exit_function() {
        free(config.nqptp_shared_memory_interface_name);
      if (config.airplay_device_id)
        free(config.airplay_device_id);
-      if (config.airplay_pin)
-        free(config.airplay_pin);
      if (config.airplay_pi)
        free(config.airplay_pi);
      if (config.airplay_pgid)
@@ -1994,7 +1984,7 @@ void exit_function() {
 #else
    mdns_unregister(); // once the dacp handler is done and all player threrads are done it should
                       // be safe
-    debug(1, "normal exit");
+    debug(2, "normal exit");
 #endif
  } else {
    debug(1, "emergency exit");
@@ -2346,6 +2336,7 @@ int main(int argc, char **argv) {
  openlog(NULL, 0, LOG_DAEMON);
 #endif
  type_of_exit_cleanup = TOE_normal; // what kind of exit cleanup needed
+  debug(1, "adding the exit function");
  atexit(exit_function);

  // get a device id -- the first non-local MAC address
@@ -2957,7 +2948,9 @@ int main(int argc, char **argv) {
              config.output_channel_map[i] = strdup(channel_id);
              debug(2, "output channel %d is \"%s\".", i, config.output_channel_map[i]);
            } else {
-              warn("channel \"%s\" is not recognised -- output channel %d will be silent.",
+            
+              
+              warn("during channel mapping, \"%s\" was not recognised as a channel name -- as a result, output channel %d will be silent.",
                   channel_id, i);
              config.output_channel_map[i] = strdup("--");
            }
@@ -3153,8 +3146,20 @@ int main(int argc, char **argv) {
  debug(option_print_level, "loudness reference level is %f", config.loudness_reference_volume_db);

 #ifdef CONFIG_SOXR
-  named_pthread_create(&soxr_time_check_thread, NULL, &soxr_time_check, NULL, "soxr_checker");
-  soxr_time_check_thread_started = 1;
+
+  {
+    int oldState;
+    pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
+    soxr_time_check_thread = malloc(sizeof(pthread_t));
+    if (soxr_time_check_thread != NULL) {
+      named_pthread_create(soxr_time_check_thread, NULL, &soxr_time_check, NULL, "soxr_checker");
+    } else {
+      debug(1,"couldn't get memory to start the soxr_checker");
+    }
+    pthread_setcancelstate(oldState, NULL); // make this un-cancellable
+
+  }
+  
 #endif

 #ifdef CONFIG_FFMPEG
@@ -3180,7 +3185,7 @@ int main(int argc, char **argv) {
          if (idx != 0)
            strncat(channel_map, " ", sizeof(channel_map) - 1);
          strncat(channel_map, chName, sizeof(channel_map) - 1 - strlen(channel_map));
-          debug(3, "Channel %d: \"%s\"", idx, chName);
+          debug(4, "Channel %d: \"%s\"", idx, chName);
        } else {
          debug(1, "Insufficient space for the name of channel %d.", idx);
        }
@@ -23,6 +23,7 @@ SOFTWARE.
 */

 #include "debug.h"
+#include <ctype.h> // for isprint()
 #include <inttypes.h>
 #include <pthread.h>
 #include <stdarg.h>
@@ -64,13 +65,9 @@ void debug_init(int level, int show_elapsed_time, int show_relative_time, int sh
  debugger_show_file_and_line = show_file_and_line;
 }

-int debug_level() {
-  return debuglev;
-};
+int debug_level() { return debuglev; };

-void set_debug_level(int level) {
-  debuglev = level;
-}
+void set_debug_level(int level) { debuglev = level; }

 void increase_debug_level() {
  if (debuglev < 3)
@@ -82,28 +79,15 @@ void decrease_debug_level() {
    debuglev--;
 }

-int get_show_elapsed_time() {
-  return debugger_show_elapsed_time;
-  
-}
-void set_show_elapsed_time(int setting) {
-  debugger_show_elapsed_time = setting;
-}
-int get_show_relative_timel() {
-  return debugger_show_relative_time;
-}
+int get_show_elapsed_time() { return debugger_show_elapsed_time; }
+void set_show_elapsed_time(int setting) { debugger_show_elapsed_time = setting; }
+int get_show_relative_timel() { return debugger_show_relative_time; }

-void set_show_relative_time(int setting) {
-  debugger_show_relative_time = setting;
-}
+void set_show_relative_time(int setting) { debugger_show_relative_time = setting; }

-int get_show_file_and_line() {
-  return debugger_show_file_and_line;
-}
+int get_show_file_and_line() { return debugger_show_file_and_line; }

-void set_show_file_and_line(int setting) {
-  debugger_show_file_and_line = setting;
-}
+void set_show_file_and_line(int setting) { debugger_show_file_and_line = setting; }

 char *generate_preliminary_string(char *buffer, size_t buffer_length, double tss, double tsl,
                                  const char *filename, const int linenumber, const char *prefix) {
@@ -244,10 +228,94 @@ void _inform(const char *filename, const int linenumber, const char *format, ...
  pthread_setcancelstate(oldState, NULL);
 }

+
+void _debug_print_buffer(const char *thefilename, const int linenumber, int level, void *ibuf,
+                         size_t buf_len) {
+
+  if (level > debuglev)
+    return;
+
+  char *vbuf = (char *)ibuf; // this to stop the compiler complaining about indexing through a void
+  unsigned int i;
+  unsigned int hexdump_cols = 16;
+  
+  // 0x123456: <hexdump_cols * 3> <hexdump_cols>\n
+  const size_t buffer_size = 2 + 6 + 2 + hexdump_cols * 3 + hexdump_cols + 1; 
+  char *buf = malloc(buffer_size);
+  if (buf) {
+    //char *bufp = buf;
+    // *buf = '\0';
+
+  // if (msg)
+  //   printf("%s", msg);
+  
+  #define ADDR_PREFIX_LEN 10  // "0x000000: "
+
+  // each complete row
+  for (i = 0; i < (buf_len / hexdump_cols); i++) {
+    char *bufp = buf;
+    *buf = '\0';
+    snprintf(bufp, ADDR_PREFIX_LEN + 1,"0x%06x  ", (i * hexdump_cols) & 0xFFFFFF);
+    bufp += ADDR_PREFIX_LEN;
+    
+    unsigned int j;
+    for (j = 0; j < hexdump_cols; j++) {
+      snprintf(bufp, strlen("12 ") + 1, "%02x ", 0xFF & vbuf[i * hexdump_cols + j]);
+      bufp += strlen("12 ");
+    }
+    
+    for (j = 0; j < hexdump_cols; j++) {
+      if (isprint(vbuf[i * hexdump_cols + j])) {
+          *bufp = 0xFF & vbuf[i * hexdump_cols + j];
+      } else {
+          *bufp = '.';
+      }
+      bufp++;
+    }
+    *bufp = '\0';
+      _debug(thefilename, linenumber, level, "%s", buf);
+  }
+
+  size_t remaining = buf_len % hexdump_cols;
+  if (remaining != 0) {
+    size_t starting_offset = buf_len - remaining;
+    char *bufp = buf;
+    *buf = '\0';
+    snprintf(bufp, ADDR_PREFIX_LEN + 1,"0x%06zx  ", starting_offset & 0xFFFFFF);
+    bufp += ADDR_PREFIX_LEN;
+
+    unsigned int j;
+    for (j = 0; j < hexdump_cols; j++) {
+      if (j < remaining) {
+        snprintf(bufp, strlen("12 ") + 1, "%02x ", 0xFF & vbuf[starting_offset + j]);
+      } else {
+        snprintf(bufp, strlen("   ") + 1, "   "); // fille with blanks
+      }
+      bufp += strlen("12 ");
+    }
+    
+    for (j = 0; j < remaining; j++) {
+      if (isprint(vbuf[i * hexdump_cols + j])) {
+          *bufp = 0xFF & vbuf[starting_offset + j];
+      } else {
+          *bufp = '.';
+      }
+      bufp++;
+    }
+    *bufp = '\0';
+      _debug(thefilename, linenumber, level, "%s", buf);
+  }
+  free(buf);
+  }
+}
+
+
+/*
 void _debug_print_buffer(const char *thefilename, const int linenumber, int level, void *vbuf,
                         size_t buf_len) {
  if (level > debuglev)
    return;
+  new_debug_print_buffer(thefilename, linenumber, level, vbuf, buf_len);
  char *buf = (char *)vbuf;
  char *obf =
      malloc(buf_len * 4 + 1); // to be on the safe side -- 4 characters on average for each byte
@@ -274,4 +342,5 @@ void _debug_print_buffer(const char *thefilename, const int linenumber, int leve
    _debug(thefilename, linenumber, level, "%s", obf);
    free(obf);
  }
-}
+}
+*/
@@ -0,0 +1,48 @@
+/*
+ * Generate a device-related UUID. This file is part of Shairport Sync
+ * Copyright (c) Mike Brady 2026
+
+ * Modifications, including those associated with audio synchronization, multithreading and
+ * metadata handling copyright (c) Mike Brady 2014--2025
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+ 
+#include <stdlib.h>
+#include <string.h>
+#include <uuid/uuid.h>
+ 
+#include "generate_device_uuid.h"
+#include "definitions.h"
+
+// user is responsible for deallocating returned string
+char *generate_device_uuid(const char *device_id) {
+    uuid_t namespace_uuid;
+    uuid_t derived_uuid;
+
+    uuid_parse(SHAIRPORT_SYNC_DEVICE_NAMESPACE, namespace_uuid); 
+    uuid_generate_sha1(derived_uuid, namespace_uuid, device_id, strlen(device_id));
+
+    char *uuid = malloc(UUID_STR_LEN + 1);
+    uuid_unparse_lower(derived_uuid, uuid);
+    return uuid;
+}
@@ -0,0 +1,3 @@
+#pragma once
+
+char *generate_device_uuid(const char *device_id);
@@ -0,0 +1,47 @@
+/*
+ * Generate a random UUID. This file is part of Shairport Sync
+ * Copyright (c) Mike Brady 2026
+
+ * Modifications, including those associated with audio synchronization, multithreading and
+ * metadata handling copyright (c) Mike Brady 2014--2025
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+ 
+#include <stdlib.h>
+#include <uuid/uuid.h>
+ 
+#include "generate_random_uuid.h"
+
+// user is responsible for deallocating returned string
+char *generate_random_uuid() {
+  // generate a UUID
+  // from https://stackoverflow.com/questions/51053568/generating-a-random-uuid-in-c
+  // with thanks
+  uuid_t binuuid;
+  uuid_generate_random(binuuid);
+
+  char *uuid = malloc(UUID_STR_LEN + 1); // leave space for the NUL at the end
+  // Produces a UUID string at uuid consisting of lower-case letters
+  uuid_unparse_lower(binuuid, uuid);
+  return uuid;
+}
@@ -0,0 +1,6 @@
+#ifndef _GENERATE_RANDOM_UUID_H
+#define _GENERATE_RANDOM_UUID_H
+
+char *generate_random_uuid();
+
+#endif // _GENERATE_RANDOM_UUID_H
@@ -38,8 +38,8 @@ int eintr_checked_accept(int sockfd, struct sockaddr *addr,
      char errorstring[1024];
      strerror_r(errno, (char *)errorstring, sizeof(errorstring));
      debug(1,
-        "error %d accept()ing a socketin ap2_event_receiver: \"%s\". (Note: error %d will be ignored.)",
-        errno, errorstring, EINTR);
+        "error %d accept()ing a socket %d: \"%s\". (Note: error %d will be ignored.)",
+        errno, sockfd, errorstring, EINTR);
    }
    
  } while((response == -1) && (errno == EINTR));
@@ -0,0 +1,265 @@
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#include <plist/plist.h>
+#include "rtsp_message_utilities.h"
+#include "../rtsp.h"
+#include "../common.h"
+
+#ifdef HAVE_LIBPLIST_GE_2_3_0
+#define plist_from_memory(plist_data, length, plist)                                               \
+  plist_from_memory((plist_data), (length), (plist), NULL)
+#endif
+
+// every time we want to retain or release a reference count, lock it with this
+// if a reference count is read as zero, it means the it's being deallocated.
+static pthread_mutex_t reference_counter_lock = PTHREAD_MUTEX_INITIALIZER;
+static int msg_indexes = 1;
+
+void msg_retain(rtsp_message *msg) {
+  int rc = debug_mutex_lock(&reference_counter_lock, 500000, 4);
+  if (rc)
+    debug(1, "Error %d locking reference counter lock", rc);
+  if (msg > (rtsp_message *)0x00010000) {
+    msg->referenceCount++;
+    debug(4, "msg_free increment reference counter message %d to %d.", msg->index_number,
+          msg->referenceCount);
+    // debug(1,"msg_retain -- item %d reference count %d.", msg->index_number, msg->referenceCount);
+    rc = pthread_mutex_unlock(&reference_counter_lock);
+    if (rc)
+      debug(1, "Error %d unlocking reference counter lock", rc);
+  } else {
+    debug(1, "invalid rtsp_message pointer 0x%" PRIxPTR " passed to retain", (uintptr_t)msg);
+  }
+}
+
+rtsp_message *msg_init(void) {
+  // no thread cancellation points here
+  int rc = debug_mutex_lock(&reference_counter_lock, 500000, 4);
+  if (rc)
+    debug(1, "Error %d locking reference counter lock", rc);
+
+  rtsp_message *msg = malloc(sizeof(rtsp_message));
+  if (msg) {
+    memset(msg, 0, sizeof(rtsp_message));
+    msg->referenceCount = 1; // from now on, any access to this must be protected with the lock
+    msg->index_number = msg_indexes++;
+    debug(4, "msg_init message %d", msg->index_number);
+  } else {
+    die("msg_init -- can not allocate memory for rtsp_message %d.", msg_indexes);
+  }
+  // debug(1,"msg_init -- create item %d.", msg->index_number);
+
+  rc = pthread_mutex_unlock(&reference_counter_lock);
+  if (rc)
+    debug(1, "Error %d unlocking reference counter lock", rc);
+
+  return msg;
+}
+
+int msg_add_header(rtsp_message *msg, char *name, char *value) {
+  if (msg->nheaders >= sizeof(msg->name) / sizeof(char *)) {
+    warn("too many headers?!");
+    return 1;
+  }
+
+  msg->name[msg->nheaders] = strdup(name);
+  msg->value[msg->nheaders] = strdup(value);
+  msg->nheaders++;
+
+  return 0;
+}
+
+char *msg_get_header(rtsp_message *msg, char *name) {
+  unsigned int i;
+  for (i = 0; i < msg->nheaders; i++)
+    if (!strcasecmp(msg->name[i], name))
+      return msg->value[i];
+  return NULL;
+}
+
+void _debug_print_msg_headers(rtsp_conn_info *conn, const char *filename, const int linenumber, int level,
+                              rtsp_message *msg) {
+  unsigned int i;
+  if (conn != NULL) {
+    if (msg->respcode != 0)
+      _debug(filename, linenumber, level, "Connection: %d,  Response Code: %d.", conn->connection_number, msg->respcode);
+    for (i = 0; i < msg->nheaders; i++) {
+      _debug(filename, linenumber, level, "Connection: %d,  Type: \"%s\", content: \"%s\"", conn->connection_number, msg->name[i],
+             msg->value[i]);
+    }
+  } else {
+    if (msg->respcode != 0)
+      _debug(filename, linenumber, level, "  Response Code: %d.", msg->respcode);
+    for (i = 0; i < msg->nheaders; i++) {
+      _debug(filename, linenumber, level, "  Type: \"%s\", content: \"%s\"", msg->name[i],
+             msg->value[i]);
+    }
+  }
+}
+
+void msg_free(rtsp_message **msgh) {
+  debug_mutex_lock(&reference_counter_lock, 1000, 0);
+  if (*msgh > (rtsp_message *)0x00010000) {
+    rtsp_message *msg = *msgh;
+    msg->referenceCount--;
+    if (msg->referenceCount)
+      debug(4, "msg_free decrement reference counter message %d to %d", msg->index_number,
+            msg->referenceCount);
+    if (msg->referenceCount == 0) {
+      unsigned int i;
+      for (i = 0; i < msg->nheaders; i++) {
+        free(msg->name[i]);
+        free(msg->value[i]);
+      }
+      if (msg->content)
+        free(msg->content);
+      // debug(1,"msg_free item %d -- free.",msg->index_number);
+      uintptr_t index = (msg->index_number) & 0xFFFF;
+      if (index == 0)
+        index = 0x10000; // ensure it doesn't fold to zero.
+      *msgh =
+          (rtsp_message *)(index); // put a version of the index number of the freed message in here
+      debug(4, "msg_free freed message %d", msg->index_number);
+      free(msg);
+    } else {
+      // debug(1,"msg_free item %d -- decrement reference to
+      // %d.",msg->index_number,msg->referenceCount);
+    }
+  } else if (*msgh != NULL) {
+    debug(1,
+          "msg_free: error attempting to free an allocated but already-freed rtsp_message, number "
+          "%" PRIxPTR ".",
+          (uintptr_t)*msgh);
+  }
+  debug_mutex_unlock(&reference_counter_lock, 0);
+}
+
+int msg_handle_line(rtsp_message **pmsg, char *line) {
+  rtsp_message *msg = *pmsg;
+
+  if (!msg) {
+    msg = msg_init();
+    *pmsg = msg;
+    char *sp, *p;
+    sp = NULL; // this is to quieten a compiler warning
+
+    debug(4, "RTSP/HTTP Message Received: \"%s\".", line);
+
+    p = strtok_r(line, " ", &sp);
+    if (!p)
+      goto fail;
+    strncpy(msg->method, p, sizeof(msg->method) - 1);
+
+    p = strtok_r(NULL, " ", &sp);
+    if (!p)
+      goto fail;
+    strncpy(msg->path, p, sizeof(msg->path) - 1);
+
+    p = strtok_r(NULL, " ", &sp);
+    if (!p)
+      goto fail;
+    if ((strcmp(p, "RTSP/1.0") != 0) && (strcmp(p, "HTTP/1.1") != 0)) {
+      debug(1, "Problem with Message: \"%s\"", p);
+      goto fail;
+    }
+
+    return -1;
+  }
+
+  if (strlen(line)) {
+    char *p;
+    p = strstr(line, ": ");
+    if (!p) {
+      warn("bad header: >>%s<<", line);
+      goto fail;
+    }
+    *p = 0;
+    p += 2;
+    msg_add_header(msg, line, p);
+    debug(4, "    %s: %s.", line, p);
+    return -1;
+  } else {
+    char *cl = msg_get_header(msg, "Content-Length");
+    if (cl)
+      return atoi(cl);
+    else
+      return 0;
+  }
+
+fail:
+  debug(1, "msg_handle_line fail");
+  msg_free(pmsg);
+  *pmsg = NULL;
+  return 0;
+}
+
+#ifdef CONFIG_AIRPLAY_2
+
+int rtsp_message_contains_plist(rtsp_message *message) {
+  int reply = 0; // assume there is no plist in the message
+  if ((message->contentlength >= strlen("bplist00")) &&
+      (strstr(message->content, "bplist00") == message->content))
+    reply = 1;
+  return reply;
+}
+
+plist_t plist_from_rtsp_content(rtsp_message *message) {
+  plist_t the_plist = NULL;
+  if (rtsp_message_contains_plist(message)) {
+    plist_from_memory(message->content, message->contentlength, &the_plist);
+  }
+  return the_plist;
+}
+
+char *plist_as_xml_text(plist_t the_plist) {
+  // caller must free the returned character buffer
+  // convert it to xml format
+  uint32_t size;
+  char *plist_out = NULL;
+  plist_to_xml(the_plist, &plist_out, &size);
+
+  // put it into a NUL-terminated string
+  char *reply = malloc(size + 1);
+  if (reply) {
+    memcpy(reply, plist_out, size);
+    reply[size] = '\0';
+  }
+  if (plist_out)
+    free(plist_out);
+  return reply;
+}
+
+// caller must free the returned character buffer
+char *rtsp_plist_content(rtsp_message *message) {
+  char *reply = NULL;
+  // first, check if it has binary plist content
+  if (rtsp_message_contains_plist(message))
+    reply = plist_as_xml_text(plist_from_rtsp_content(message));
+  return reply;
+}
+
+#endif
+
+void _debug_log_rtsp_message(rtsp_conn_info *conn, const char *filename, const int linenumber, int level, char *prompt,
+                             rtsp_message *message) {
+  if (level > debug_level())
+    return;
+  if ((prompt) && (*prompt != '\0')) // okay to pass NULL or an empty list...
+    _debug(filename, linenumber, level, "%s", prompt);
+  _debug_print_msg_headers(conn, filename, linenumber, level, message);
+#ifdef CONFIG_AIRPLAY_2
+  char *plist_content = rtsp_plist_content(message);
+  if (plist_content) {
+    _debug(filename, linenumber, level, "  Content length: %u. Content Plist (as XML):\n--\n%s--", message->contentlength, plist_content);
+    free(plist_content);
+  } else
+#endif
+  {
+    _debug(filename, linenumber, level, "  No Content Plist. Content length: %u.",
+           message->contentlength);
+    if (message->contentlength > 0) {
+      _debug_print_buffer(filename, linenumber, level, message->content, message->contentlength);
+    }
+  }
+}
@@ -0,0 +1,33 @@
+#pragma once
+
+#include "player.h"
+#include "rtsp.h"
+
+rtsp_message *msg_init(void);
+int msg_handle_line(rtsp_message **pmsg, char *line);
+int msg_add_header(rtsp_message *msg, char *name, char *value);
+char *msg_get_header(rtsp_message *msg, char *name);
+
+void _debug_log_rtsp_message(rtsp_conn_info *conn, const char *filename, const int linenumber, int level, char *prompt,
+                             rtsp_message *message);
+
+#define debug_log_rtsp_message_conn(conn, level, prompt, message)                                  \
+  _debug_log_rtsp_message(conn, __FILE__, __LINE__, level, prompt, message)
+
+#define debug_log_rtsp_message(level, prompt, message)                                             \
+  _debug_log_rtsp_message(NULL, __FILE__, __LINE__, level, prompt, message)
+
+
+void _debug_print_msg_headers(rtsp_conn_info *conn, const char *filename, const int linenumber, int level,
+                              rtsp_message *msg);
+#define debug_print_msg_headers(level, message)                                                    \
+  _debug_print_msg_headers(NULL, __FILE__, __LINE__, level, message)
+
+#define debug_print_msg_headers_conn(level, message)                                               \
+  _debug_print_msg_headers(conn, __FILE__, __LINE__, level, message)
+
+
+#ifdef CONFIG_AIRPLAY_2
+int rtsp_message_contains_plist(rtsp_message *message);
+plist_t plist_from_rtsp_content(rtsp_message *message);
+#endif