Merge pull request #809 from nettings/development

Modify audio_jack.c to use native jack lockless buffers and to offer auto connect facilities. Overall, the backend is now written more in the idiom of jack audio.

Many thanks to [Jörn Nettingsmeier](https://github.com/nettings).
This commit is contained in:
Mike Brady
2019-02-19 11:12:03 +00:00
committed by GitHub
3 changed files with 252 additions and 338 deletions
+242 -329
View File
@@ -1,6 +1,7 @@
/*
* jack output driver. This file is part of Shairport Sync.
* Copyright (c) 2018 Mike Brady <mikebrady@iercom.net>
* Copyright (c) 2019 Mike Brady <mikebrady@iercom.net>,
* Jörn Nettingsmeier <nettings@luchtbeweging.nl>
*
* All rights reserved.
*
@@ -19,41 +20,28 @@
#include "audio.h"
#include "common.h"
#include <errno.h>
#include <getopt.h>
#include <limits.h>
#include <math.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <limits.h>
#include <pthread.h>
#include <string.h>
#include <unistd.h>
#include <jack/jack.h>
#include <jack/transport.h>
enum ift_type {
IFT_frame_left_sample = 0,
IFT_frame_right_sample,
} ift_type;
#include <jack/ringbuffer.h>
// Two-channel, 16bit audio:
static const int bytes_per_frame = 4;
// Four seconds buffer -- should be plenty
#define buffer_size 44100 * 4 * 2 * 2
#define buffer_size (44100 * 4 * bytes_per_frame)
static pthread_mutex_t buffer_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t client_mutex = PTHREAD_MUTEX_INITIALIZER;
char *audio_lmb, *audio_umb, *audio_toq, *audio_eoq;
size_t audio_occupancy; // this is in frames, not bytes. A frame is a left and
// right sample, each 16 bits, hence 4 bytes
pthread_t *open_client_if_necessary_thread = NULL;
int jack_init(int, char **);
void jack_deinit(void);
void jack_start(int, int);
int play(void *, int);
void jack_stop(void);
int jack_is_running(void);
int jack_delay(long *);
void jack_flush(void);
@@ -62,8 +50,8 @@ audio_output audio_jack = {.name = "jack",
.init = &jack_init,
.deinit = &jack_deinit,
.start = &jack_start,
.stop = &jack_stop,
.is_running = &jack_is_running,
.stop = NULL,
.is_running = NULL,
.flush = &jack_flush,
.delay = &jack_delay,
.play = &play,
@@ -71,366 +59,291 @@ audio_output audio_jack = {.name = "jack",
.parameters = NULL,
.mute = NULL};
jack_port_t *left_port;
jack_port_t *right_port;
// This also affects deinterlacing.
// So make it exactly the number of incoming audio channels!
#define NPORTS 2
static jack_port_t *port[NPORTS];
static const char* port_name[NPORTS] = { "out_L", "out_R" };
long offset = 0;
static jack_client_t *client;
static jack_nframes_t sample_rate;
static jack_nframes_t jack_latency;
int client_is_open;
jack_client_t *client;
jack_nframes_t sample_rate;
jack_nframes_t jack_latency;
static jack_ringbuffer_t *jackbuf;
static int flush_please = 0;
jack_latency_range_t latest_left_latency_range, latest_right_latency_range;
int64_t time_of_latest_transfer;
static jack_latency_range_t latest_latency_range[NPORTS];
static int64_t time_of_latest_transfer;
int play(void *buf, int samples) {
// debug(1,"jack_play of %d samples.",samples);
// copy the samples into the queue
size_t bytes_to_transfer = samples * 2 * 2;
size_t space_to_end_of_buffer = audio_umb - audio_eoq;
if (space_to_end_of_buffer >= bytes_to_transfer) {
memcpy(audio_eoq, buf, bytes_to_transfer);
pthread_mutex_lock(&buffer_mutex);
audio_occupancy += samples;
audio_eoq += bytes_to_transfer;
pthread_mutex_unlock(&buffer_mutex);
} else {
memcpy(audio_eoq, buf, space_to_end_of_buffer);
buf += space_to_end_of_buffer;
memcpy(audio_lmb, buf, bytes_to_transfer - space_to_end_of_buffer);
pthread_mutex_lock(&buffer_mutex);
audio_occupancy += samples;
audio_eoq = audio_lmb + bytes_to_transfer - space_to_end_of_buffer;
pthread_mutex_unlock(&buffer_mutex);
}
return 0;
static inline jack_default_audio_sample_t sample_conv(short sample) {
// It sounds correct, but I don't understand it.
// Zero int needs to be zero float. Check.
// Plus 32767 int is 1.0. Check.
// Minus 32767 int is -0.99997. And here my brain shuts down.
// In my head, it should be 1.0, and we should tolerate an overflow
// at minus 32768. But I'm sure there's a textbook explanation somewhere.
return ((sample < 0) ? (-1.0 * sample / SHRT_MIN) : (1.0 * sample / SHRT_MAX));
}
void deinterleave_and_convert_stream(const char *interleaved_frames,
const jack_default_audio_sample_t *jack_frame_buffer,
jack_nframes_t number_of_frames, enum ift_type side) {
jack_nframes_t i;
short *ifp = (short *)interleaved_frames;
jack_default_audio_sample_t *fp = (jack_default_audio_sample_t *)jack_frame_buffer;
if (side == IFT_frame_right_sample)
ifp++;
for (i = 0; i < number_of_frames; i++) {
short sample = *ifp;
jack_default_audio_sample_t converted_value;
if (sample >= 0)
converted_value = (1.0 * sample) / SHRT_MAX;
else
converted_value = -(1.0 * sample) / SHRT_MIN;
*fp = converted_value;
ifp++;
ifp++;
fp++;
}
}
int jack_stream_write_cb(jack_nframes_t nframes, __attribute__((unused)) void *arg) {
jack_default_audio_sample_t *left_buffer =
(jack_default_audio_sample_t *)jack_port_get_buffer(left_port, nframes);
jack_default_audio_sample_t *right_buffer =
(jack_default_audio_sample_t *)jack_port_get_buffer(right_port, nframes);
size_t frames_we_can_transfer = nframes;
// lock
pthread_mutex_lock(&buffer_mutex);
if (audio_occupancy < frames_we_can_transfer) {
frames_we_can_transfer = audio_occupancy;
// This means we effectively have underflow from the Shairport Sync source.
// In fact, it may be that there is nothing at all coming from the source,
// but the Shairport Sync client is open and active, so it must continue to output something.
}
if (frames_we_can_transfer * 2 * 2 <= (size_t)(audio_umb - audio_toq)) {
// the bytes are all in a row in the audio buffer
deinterleave_and_convert_stream(audio_toq, &left_buffer[0], frames_we_can_transfer,
IFT_frame_left_sample);
deinterleave_and_convert_stream(audio_toq, &right_buffer[0], frames_we_can_transfer,
IFT_frame_right_sample);
audio_toq += frames_we_can_transfer * 2 * 2;
} else {
// the bytes are in two places in the audio buffer
size_t first_portion_to_write = (audio_umb - audio_toq) / (2 * 2);
if (first_portion_to_write != 0) {
deinterleave_and_convert_stream(audio_toq, &left_buffer[0], first_portion_to_write,
IFT_frame_left_sample);
deinterleave_and_convert_stream(audio_toq, &right_buffer[0], first_portion_to_write,
IFT_frame_right_sample);
static void deinterleave_and_convert(const char *interleaved_input_buffer,
jack_default_audio_sample_t* jack_output_buffer[],
jack_nframes_t offset,
jack_nframes_t nframes) {
jack_nframes_t f;
// We're dealing with 16bit audio here:
short *ifp = (short *)interleaved_input_buffer;
// Zero-copy, we're working directly on the target and destination buffers,
// so deal with an offset for the second part of the input ringbuffer
for (f = offset; f < (nframes + offset); f++) {
for (int i = 0; i < NPORTS; i++) {
jack_output_buffer[i][f] = sample_conv(*ifp++);
}
deinterleave_and_convert_stream(audio_lmb, &left_buffer[first_portion_to_write],
frames_we_can_transfer - first_portion_to_write,
IFT_frame_left_sample);
deinterleave_and_convert_stream(audio_lmb, &right_buffer[first_portion_to_write],
frames_we_can_transfer - first_portion_to_write,
IFT_frame_right_sample);
audio_toq = audio_lmb + (frames_we_can_transfer - first_portion_to_write) * 2 * 2;
}
// debug(1,"transferring %u frames",frames_we_can_transfer);
audio_occupancy -= frames_we_can_transfer;
jack_port_get_latency_range(left_port, JackPlaybackLatency, &latest_left_latency_range);
jack_port_get_latency_range(right_port, JackPlaybackLatency, &latest_right_latency_range);
time_of_latest_transfer = get_absolute_time_in_fp();
pthread_mutex_unlock(&buffer_mutex);
// unlock
// now, if there are any more frames to put into the buffer, fill them with
// silence
jack_nframes_t i;
for (i = frames_we_can_transfer; i < nframes; i++) {
left_buffer[i] = 0.0;
right_buffer[i] = 0.0;
}
return 0;
}
void default_jack_error_callback(const char *desc) { debug(2, "jackd error: \"%s\"", desc); }
void default_jack_info_callback(const char *desc) { inform("jackd information: \"%s\"", desc); }
void default_jack_set_latency_callback(jack_latency_callback_mode_t mode,
__attribute__((unused)) void *arg) {
if (mode == JackPlaybackLatency) {
jack_latency_range_t left_latency_range, right_latency_range;
jack_port_get_latency_range(left_port, JackPlaybackLatency, &left_latency_range);
jack_port_get_latency_range(right_port, JackPlaybackLatency, &right_latency_range);
jack_nframes_t b_latency = (left_latency_range.min + left_latency_range.max) / 2;
if (b_latency == 0)
b_latency = (right_latency_range.min + right_latency_range.max) / 2;
// jack_latency = b_latency; // actually, we are not interested in the latency of the jack
// devices connected...
jack_latency = 0;
debug(1, "playback latency callback: %" PRIu32 ".", jack_latency);
}
}
int jack_is_running() {
int reply = -1; // meaning jack is not running
// if the client is open and initialised, see if the status is "rolling"
if (client_is_open) {
// This is the JACK process callback. We don't decide when it runs.
// It must be hard-realtime safe (i.e. fully deterministic, with constant CPU
// usage. No calls to anything that could ever block: no syscalls, no screen
// output, no file access, no mutexes...
// The JACK ringbuffer we use to get the data in here is explicitly lock-free.
static int process(jack_nframes_t nframes, __attribute__((unused)) void *arg) {
jack_default_audio_sample_t *buffer[NPORTS];
// Expect an array of two elements because of possible ringbuffer wrap-around:
jack_ringbuffer_data_t v[2] = { 0 };
jack_nframes_t i, thisbuf;
int frames_written = 0;
int frames_required = 0;
// check if the ports have a zero latency -- if they both have, then it's disconnected.
jack_latency_range_t left_latency_range, right_latency_range;
jack_port_get_latency_range(left_port, JackPlaybackLatency, &left_latency_range);
jack_port_get_latency_range(right_port, JackPlaybackLatency, &right_latency_range);
// if ((left_latency_range.min == 0) && (left_latency_range.max == 0) &&
// (right_latency_range.min == 0) && (right_latency_range.max == 0)) {
// reply = -2; // meaning Shairport Sync is not connected
// } else {
reply = 0; // meaning jack is open and Shairport Sync is connected to it
// }
for (i = 0; i < NPORTS; i++) {
buffer[i] = (jack_default_audio_sample_t *)jack_port_get_buffer(port[i], nframes);
}
return reply;
}
int jack_client_open_if_needed(void) {
pthread_mutex_lock(&client_mutex);
if (client_is_open == 0) {
jack_status_t status;
client = jack_client_open(config.jack_client_name, JackNoStartServer, &status);
if (client) {
jack_set_process_callback(client, jack_stream_write_cb, 0);
left_port = jack_port_register(client, config.jack_left_channel_name, JACK_DEFAULT_AUDIO_TYPE,
JackPortIsOutput, 0);
right_port = jack_port_register(client, config.jack_right_channel_name,
JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0);
sample_rate = jack_get_sample_rate(client);
// debug(1, "jackaudio sample rate = %" PRId32 ".", sample_rate);
if (sample_rate == 44100) {
if (jack_set_latency_callback(client, default_jack_set_latency_callback, NULL) == 0) {
if (jack_activate(client)) {
debug(1, "jackaudio cannot activate client");
} else {
debug(2, "jackaudio client opened.");
client_is_open = 1;
}
} else {
debug(1, "jackaudio cannot set latency callback");
}
} else {
inform(
"jackaudio is running at the wrong speed (%d) for Shairport Sync, which must be 44100",
sample_rate);
if (flush_please) {
// We just move the read pointer ahead without doing anything with the data.
jack_ringbuffer_read_advance(jackbuf, jack_ringbuffer_read_space(jackbuf));
flush_please = 0;
// Since we don't change nframes, the whole buffer will be zeroed later.
} else {
jack_ringbuffer_get_read_vector(jackbuf, v);
for (i = 0; i < 2; i++) {
thisbuf = v[i].len / bytes_per_frame;
if (thisbuf > nframes) {
frames_required = nframes;
} else {
frames_required = thisbuf;
}
deinterleave_and_convert(v[i].buf, buffer, frames_written, frames_required);
frames_written += frames_required;
nframes -= frames_required;
}
jack_ringbuffer_read_advance(jackbuf, frames_written * bytes_per_frame);
}
pthread_mutex_unlock(&client_mutex);
return client_is_open;
}
void jack_close(void) {
pthread_mutex_lock(&client_mutex);
if (client_is_open) {
if (jack_deactivate(client))
debug(1, "Error deactivating jack client");
if (jack_client_close(client))
debug(1, "Error closing jack client");
client_is_open = 0;
}
pthread_mutex_unlock(&client_mutex);
}
void jack_deinit() {
jack_close();
if (open_client_if_necessary_thread) {
pthread_cancel(*open_client_if_necessary_thread);
free((char *)open_client_if_necessary_thread);
}
}
void *open_client_if_necessary_thread_function(void *arg) {
int *interval = (int *)arg;
while (*interval != 0) {
if (client_is_open == 0) {
debug(1, "Try to open the jack client");
jack_client_open_if_needed();
// If there are any more frames to put into the buffer, fill them with
// silence. This is a critical underflow situation. Let's at least keep the JACK
// graph humming along while preventing the motorboat sound of a repeating buffer.
while (nframes > 0) {
for (i = 0; i < NPORTS; i++) {
buffer[i][frames_written] = 0.0;
}
sleep(*interval);
frames_written++;
nframes--;
}
pthread_exit(NULL);
return 0; // Tell JACK that all is well.
}
// This is the JACK graph reorder callback. Now we know some JACK connections
// have changed, so we recompute the latency.
static int graph(__attribute__((unused)) void * arg) {
int latency = 0;
debug(2, "JACK graph reorder callback called.");
for (int i=0; i<NPORTS; i++) {
jack_port_get_latency_range(port[i], JackPlaybackLatency, &latest_latency_range[i]);
debug(2, "JACK latency for port %s\tmin: %d\t max: %d",
port_name[i], latest_latency_range[i].min, latest_latency_range[i].max);
latency += latest_latency_range[i].max;
}
latency /= NPORTS;
jack_latency = latency;
debug(1, "Average maximum JACK latency across all ports: %d", jack_latency);
return 0;
}
// This the function JACK will call in case of an error in the library.
static void error(const char *desc) {
warn("JACK error: \"%s\"", desc);
}
// This is the function JACK will call in case of a non-critical event in the library.
static void info(const char *desc) {
inform("JACK information: \"%s\"", desc);
}
int jack_init(__attribute__((unused)) int argc, __attribute__((unused)) char **argv) {
int i;
config.audio_backend_latency_offset = 0;
config.audio_backend_buffer_desired_length = 0.500;
config.audio_backend_buffer_interpolation_threshold_in_seconds =
0.25; // below this, soxr interpolation will not occur -- it'll be basic interpolation
// instead.
config.jack_auto_client_open_interval = 1; // check every second
// Below this, soxr interpolation will not occur -- it'll be basic interpolation
// instead.
config.audio_backend_buffer_interpolation_threshold_in_seconds = 0.25;
// get settings from settings file first, allow them to be overridden by
// command line options
// do the "general" audio options. Note, these options are in the "general" stanza!
// Do the "general" audio options. Note, these options are in the "general" stanza!
parse_general_audio_options();
// other options would be picked up here...
// now the specific options
// Now the options specific to the backend, from the "jack" stanza:
if (config.cfg != NULL) {
const char *str;
int value;
/* Get the Client Name. */
if (config_lookup_string(config.cfg, "jack.client_name", &str)) {
config.jack_client_name = (char *)str;
}
/* Get the Left Channel Name. */
if (config_lookup_string(config.cfg, "jack.left_channel_name", &str)) {
config.jack_left_channel_name = (char *)str;
if (config_lookup_string(config.cfg, "jack.autoconnect_pattern", &str)) {
config.jack_autoconnect_pattern = (char *)str;
}
/* Get the Right Channel Name. */
if (config_lookup_string(config.cfg, "jack.right_channel_name", &str)) {
config.jack_right_channel_name = (char *)str;
}
/* See if we should attempt to connect to the jack server automatically, and, if so, how often
* we should try. */
if (config_lookup_int(config.cfg, "jack.auto_client_open_interval", &value)) {
if ((value < 0) || (value > 300))
debug(1,
"Invalid jack auto_client_open_interval \"%sd\". It should be between 0 and 300, "
"default is %d.",
value, config.jack_auto_client_open_interval);
else
config.jack_auto_client_open_interval = value;
}
/* See if we should close the client at then end of a play session. */
config_set_lookup_bool(config.cfg, "jack.auto_client_disconnect",
&config.jack_auto_client_disconnect);
}
if (config.jack_client_name == NULL)
config.jack_client_name = strdup("Shairport Sync");
if (config.jack_left_channel_name == NULL)
config.jack_left_channel_name = strdup("left");
if (config.jack_right_channel_name == NULL)
config.jack_right_channel_name = strdup("right");
config.jack_client_name = strdup("shairport-sync");
jack_set_error_function(default_jack_error_callback);
jack_set_info_function(default_jack_info_callback);
// allocate space for the audio buffer
audio_lmb = malloc(buffer_size);
if (audio_lmb == NULL)
die("Can't allocate %d bytes for jackaudio buffer.", buffer_size);
audio_toq = audio_eoq = audio_lmb;
audio_umb = audio_lmb + buffer_size;
audio_occupancy = 0; // frames
client_is_open = 0;
// now, if selected, start a thread to automatically open a client when there is a server.
if (config.jack_auto_client_open_interval != 0) {
open_client_if_necessary_thread = malloc(sizeof(pthread_t));
if (open_client_if_necessary_thread == NULL) {
debug(1, "Couldn't allocate space for jack server scanner thread");
jack_client_open_if_needed();
} else {
pthread_create(open_client_if_necessary_thread, NULL,
open_client_if_necessary_thread_function,
&config.jack_auto_client_open_interval);
}
} else {
jack_client_open_if_needed();
jackbuf = jack_ringbuffer_create(buffer_size);
if (jackbuf == NULL)
die("Can't allocate %d bytes for the JACK ringbuffer.", buffer_size);
// Lock the ringbuffer into memory so that it never gets paged out, which would
// break realtime constraints.
jack_ringbuffer_mlock(jackbuf);
// This mutex should not be necessary, but removing it causes segfaults on
// shutdown. Apparently, there are multiple threads in the main program trying
// to do stuff. FIXME: Try to consolidate into one thread and get rid of this lock.
pthread_mutex_lock(&client_mutex);
jack_status_t status;
client = jack_client_open(config.jack_client_name, JackNoStartServer, &status);
if (!client) {
die("Could not start JACK server. JackStatus is %x", status);
}
sample_rate = jack_get_sample_rate(client);
if (sample_rate != 44100) {
die("The JACK server is running at the wrong sample rate (%d) for Shairport Sync."
" Must be 44100 Hz.", sample_rate);
}
jack_set_process_callback(client, &process, NULL);
jack_set_graph_order_callback(client, &graph, NULL);
jack_set_error_function(&error);
jack_set_info_function(&info);
for (i=0; i < NPORTS; i++) {
port[i] = jack_port_register(client, port_name[i], JACK_DEFAULT_AUDIO_TYPE,
JackPortIsOutput, 0);
}
if (jack_activate(client)) {
die("Could not activate %s JACK client.", config.jack_client_name);
} else {
debug(2, "JACK client %s activated sucessfully.", config.jack_client_name);
}
if (config.jack_autoconnect_pattern != NULL) {
inform("config.jack_autoconnect_pattern is %s. If you see the program die after this,"
"you made a syntax error.", config.jack_autoconnect_pattern);
// Sadly, this will throw a segfault if the user provides a syntactically incorrect regex.
// I've reported it to the jack-devel mailing list, they're in a better place to fix it.
const char** port_list = jack_get_ports(client, config.jack_autoconnect_pattern,
JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput);
if (port_list != NULL) {
for (i = 0; i < NPORTS ; i++) {
char* full_port_name[NPORTS];
full_port_name[i] = malloc(sizeof(char) * jack_port_name_size());
sprintf(full_port_name[i], "%s:%s", config.jack_client_name, port_name[i]);
if (port_list[i] != NULL) {
int err;
debug(2, "Connecting %s to %s.", full_port_name[i], port_list[i]);
err = jack_connect(client, full_port_name[i], port_list[i]);
switch (err) {
case EEXIST:
inform("The requested connection from %s to %s already exists.",
full_port_name[i], port_list[i]);
break;
case 0:
// success
break;
default:
warn("JACK error no. %d occured while trying to connect %s to %s.",
err, full_port_name[i], port_list[i]);
break;
}
} else {
inform("No matching port found in %s to connect %s to. You may not hear audio.",
config.jack_autoconnect_pattern, full_port_name[i]);
}
free(full_port_name[i]);
}
while (port_list[i++] != NULL) {
inform("Additional matching port %s found. Check that the connections are what you intended.");
}
jack_free(port_list);
}
}
pthread_mutex_unlock(&client_mutex);
return 0;
}
void jack_deinit() {
pthread_mutex_lock(&client_mutex);
if (jack_deactivate(client))
warn("Error deactivating jack client");
if (jack_client_close(client))
warn("Error closing jack client");
pthread_mutex_unlock(&client_mutex);
jack_ringbuffer_free(jackbuf);
}
void jack_start(__attribute__((unused)) int i_sample_rate,
__attribute__((unused)) int i_sample_format) {
// debug(1, "jack start");
// see if the client is running. If not, try to open and initialise it
// Nothing to do, JACK client has already been set up at jack_init().
// Also, we have no say over the sample rate or sample format of JACK,
// We convert the 16bit samples to float, and die if the sample rate is != 44k1.
// FIXME: later, resampling would be nice. Fold into soxr if possible.
}
if (jack_client_open_if_needed() == 0)
debug(1, "cannot open a jack client for a play session");
void jack_flush() {
debug(2, "Only the consumer can safely flush a lock-free ringbuffer. Asking the"
" process callback to do it...");
flush_please = 1;
}
int jack_delay(long *the_delay) {
// without the mutex, we could get the time of what is the last transfer of data to a jack buffer,
// but then a transfer could occur and we would get the buffer occupancy after another transfer
// had occurred
// so we could "lose" a full transfer (e.g. 1024 frames @ 44,100 fps ~ 23.2 milliseconds)
// Semantics change: we now look at the last transfer into the lock-free
// ringbuffer, not into the jack buffers directly (because locking those would
// violate real-time constraints). On average, that should lead to just a
// constant additional latency.
// Without the mutex, we could get the time of what is the last transfer of data
// to a jack buffer, but then a transfer could occur and we would get the buffer
// occupancy after another transfer had occurred, so we could "lose" a full transfer
// (e.g. 1024 frames @ 44,100 fps ~ 23.2 milliseconds)
pthread_mutex_lock(&buffer_mutex);
int64_t time_now = get_absolute_time_in_fp();
int64_t delta = time_now - time_of_latest_transfer; // this is the time back to the last time data
// was transferred into a jack buffer
size_t audio_occupancy_now = audio_occupancy; // this is the buffer occupancy before any
// subsequent transfer because transfer is blocked
// by the mutex
int64_t time_now = get_absolute_time_in_fp();
int64_t delta = time_now - time_of_latest_transfer;
size_t audio_occupancy_now = jack_ringbuffer_read_space(jackbuf) / bytes_per_frame;
debug(2, "audio_occupancy_now is %d.", audio_occupancy_now);
pthread_mutex_unlock(&buffer_mutex);
int64_t frames_processed_since_latest_latency_check = (delta * 44100) >> 32;
// debug(1,"delta: %" PRId64 " frames.",frames_processed_since_latest_latency_check);
jack_nframes_t base_latency = (latest_left_latency_range.min + latest_left_latency_range.max) / 2;
if (base_latency == 0)
base_latency = (latest_right_latency_range.min + latest_right_latency_range.max) / 2;
*the_delay = base_latency + audio_occupancy_now - frames_processed_since_latest_latency_check;
// jack_latency is set by the graph() callback, it's the average of the maximum
// latencies of all our output ports. Adjust this constant baseline delay according
// to the buffer fill level:
*the_delay = jack_latency + audio_occupancy_now - frames_processed_since_latest_latency_check;
// debug(1,"reporting a delay of %d frames",*the_delay);
return 0;
}
void jack_flush() {
// debug(1,"jack flush");
int play(void *buf, int samples) {
// debug(1,"jack_play of %d samples.",samples);
// copy the samples into the queue
size_t bytes_to_transfer, bytes_transferred;
bytes_to_transfer = samples * bytes_per_frame;
// It's ok to lock here since we're not in the realtime callback:
pthread_mutex_lock(&buffer_mutex);
audio_toq = audio_eoq = audio_lmb;
audio_umb = audio_lmb + buffer_size;
audio_occupancy = 0; // frames
bytes_transferred = jack_ringbuffer_write(jackbuf, buf, bytes_to_transfer);
time_of_latest_transfer = get_absolute_time_in_fp();
pthread_mutex_unlock(&buffer_mutex);
}
void jack_stop(void) {
// debug(1, "jack stop");
if (config.jack_auto_client_disconnect)
jack_close();
if (bytes_transferred < bytes_to_transfer) {
warn("JACK ringbuffer overrun. Only wrote %d of %d bytes.",
bytes_transferred, bytes_to_transfer);
}
return 0;
}
+2 -4
View File
@@ -232,10 +232,8 @@ typedef struct {
double diagnostic_drop_packet_fraction; // pseudo randomly drop this fraction of packets, for
// debugging. Currently audio packets only...
#ifdef CONFIG_JACK
char *jack_client_name, *jack_left_channel_name, *jack_right_channel_name;
int jack_auto_client_open_interval; // will try to open a client automatically every second
int jack_auto_client_disconnect; // will disconnect from the server on end of session if set,
// normally clear.
char *jack_client_name;
char *jack_autoconnect_pattern;
#endif
} shairport_cfg;
+8 -5
View File
@@ -108,11 +108,14 @@ pa =
// Parameters for the "jack" JACK Audio Connection Kit backend.
jack =
{
// client_name = "Shairport Sync"; //Set this to the name of the client that should appear in "Connections" when Shairport Sync is active.
// left_channel_name = "left"; //Set this to the name of the left output port that should appear in "Connections" when Shairport Sync is active.
// right_channel_name = "right"; //Set this to the name of the right output port that should appear in "Connections" when Shairport Sync is active.
// auto_client_open_interval = 1; // Set this to the interval in seconds between automatic attempts to open a client on the jack server. Set to zero to disable this behaviour.
// auto_client_disconnect = "no"; // Set this to "yes" to close the jack client automatically at then end of a play session. Default is no -- the client stays connected.
// client_name = "shairport-sync"; // Set this to the name of the client that should appear in "Connections" when Shairport Sync is active.
// autoconnect_pattern = ""; // Set this to a POSIX regular expression pattern that describes the ports you would like to connect to
// automatically. Examples:
// "system:playback_[12]"
// "some_app_[0-9]*:in-[LR]"
// "jack_mixer:in_2[78]"
// Beware: if you make a syntax error, libjack might crash. In that case, fix it and start over.
// For a good overview, look here: https://www.ibm.com/support/knowledgecenter/SS8NLW_11.0.1/com.ibm.swg.im.infosphere.dataexpl.engine.doc/c_posix-regex-examples.html
};
// Parameters for the "pipe" audio back end, a back end that directs raw CD-style audio output to a pipe. No interpolation is done.