nils/shairport-sync
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Send silence when no audio is coming through from Shairport Sync. This eliminates (?) xrun errors. Clean up a few imprefections.

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This commit is contained in:
Mike Brady
2023-10-02 10:06:55 +01:00
parent 29a5589be6
commit dc197ae711
1 changed files with 65 additions and 44 deletions
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audio_pw.c
+65 -44
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@@ -26,7 +26,7 @@
// This uses ideas from the tone generator sample code at:
// https://github.com/PipeWire/pipewire/blob/master/src/examples/audio-src.c
// Thanks to the Wim Taymans.
// Thanks to Wim Taymans.
#include "audio.h"
#include "common.h"
@@ -39,7 +39,7 @@
#include <pipewire/pipewire.h>
#include <spa/param/audio/format-utils.h>
// note -- these are hacked and hardwired into this code.
// note -- these are hardwired into this code.
#define DEFAULT_FORMAT SPA_AUDIO_FORMAT_S16_LE
#define DEFAULT_RATE 44100
#define DEFAULT_CHANNELS 2
@@ -52,8 +52,7 @@ static pthread_mutex_t buffer_mutex = PTHREAD_MUTEX_INITIALIZER;
static char *audio_lmb, *audio_umb, *audio_toq, *audio_eoq;
static size_t audio_size = buffer_allocation;
static size_t audio_occupancy;
uint64_t starting_time;
static int enable_fill;
struct timing_data {
int pw_time_is_valid; // set when the pw_time has been set
@@ -72,10 +71,9 @@ struct data {
};
// the pipewire global data structure
struct data data = {
0,
};
struct data data = {NULL, NULL};
/*
static void on_state_changed(__attribute__((unused)) void *userdata, enum pw_stream_state old,
enum pw_stream_state state,
__attribute__((unused)) const char *error) {
@@ -83,6 +81,7 @@ static void on_state_changed(__attribute__((unused)) void *userdata, enum pw_str
debug(3, "pw: stream state changed %s -> %s", pw_stream_state_as_string(old),
pw_stream_state_as_string(state));
}
*/
static void on_process(void *userdata) {
@@ -91,52 +90,63 @@ static void on_process(void *userdata) {
pthread_mutex_lock(&buffer_mutex);
if (audio_occupancy > 0) {
if ((audio_occupancy > 0) || (enable_fill)) {
// get a buffer to see how big it can be
struct pw_buffer *b = pw_stream_dequeue_buffer(data->stream);
if (b == NULL) {
pw_log_warn("out of buffers: %m");
return;
die("PipeWire failue -- out of buffers!");
}
struct spa_buffer *buf = b->buffer;
uint8_t *dest = buf->datas[0].data;
if (dest == NULL) // the first data block does not contain a data pointer
return;
if (dest != NULL) {
int stride = sizeof(int16_t) * DEFAULT_CHANNELS;
// note: the requested field is the number of frames, not bytes, requested
int max_possible_frames = SPA_MIN(b->requested, buf->datas[0].maxsize / stride);
int stride = sizeof(int16_t) * DEFAULT_CHANNELS;
int max_possible_frames = SPA_MIN(b->requested, buf->datas[0].maxsize / stride);
size_t bytes_we_can_transfer = max_possible_frames * stride;
size_t bytes_we_can_transfer = max_possible_frames * stride;
if (audio_occupancy > 0) {
// if (enable_fill == 1)) {
// debug(1, "got audio -- disable_fill");
// }
enable_fill = 0;
if (bytes_we_can_transfer > audio_occupancy)
bytes_we_can_transfer = audio_occupancy;
if (bytes_we_can_transfer > audio_occupancy)
bytes_we_can_transfer = audio_occupancy;
n_frames = bytes_we_can_transfer / stride;
n_frames = bytes_we_can_transfer / stride;
size_t bytes_to_end_of_buffer = (size_t)(audio_umb - audio_toq); // must be zero or positive
size_t bytes_to_end_of_buffer = (size_t)(audio_umb - audio_toq); // must be zero or positive
if (bytes_we_can_transfer <= bytes_to_end_of_buffer) {
// the bytes are all in a row in the audio buffer
memcpy(dest, audio_toq, bytes_we_can_transfer);
audio_toq += bytes_we_can_transfer;
} else {
// the bytes are in two places in the audio buffer
size_t first_portion_to_write = audio_umb - audio_toq;
if (first_portion_to_write != 0)
memcpy(dest, audio_toq, first_portion_to_write);
uint8_t *new_dest = dest + first_portion_to_write;
memcpy(new_dest, audio_lmb, bytes_we_can_transfer - first_portion_to_write);
audio_toq = audio_lmb + bytes_we_can_transfer - first_portion_to_write;
}
audio_occupancy -= bytes_we_can_transfer;
if (bytes_we_can_transfer <= bytes_to_end_of_buffer) {
// the bytes are all in a row in the audio buffer
memcpy(dest, audio_toq, bytes_we_can_transfer);
audio_toq += bytes_we_can_transfer;
} else {
// the bytes are in two places in the audio buffer
size_t first_portion_to_write = audio_umb - audio_toq;
if (first_portion_to_write != 0)
memcpy(dest, audio_toq, first_portion_to_write);
uint8_t *new_dest = dest + first_portion_to_write;
memcpy(new_dest, audio_lmb, bytes_we_can_transfer - first_portion_to_write);
audio_toq = audio_lmb + bytes_we_can_transfer - first_portion_to_write;
}
buf->datas[0].chunk->offset = 0;
buf->datas[0].chunk->stride = stride;
buf->datas[0].chunk->size = n_frames * stride;
pw_stream_queue_buffer(data->stream, b);
debug(3, "Queueing %d frames for output.", n_frames);
audio_occupancy -= bytes_we_can_transfer;
} else {
debug(3, "send silence");
// this should really be dithered silence
memset(dest, 0, bytes_we_can_transfer);
n_frames = max_possible_frames;
}
buf->datas[0].chunk->offset = 0;
buf->datas[0].chunk->stride = stride;
buf->datas[0].chunk->size = n_frames * stride;
pw_stream_queue_buffer(data->stream, b);
debug(3, "Queueing %d frames for output.", n_frames);
} // (else the first data block does not contain a data pointer)
}
pthread_mutex_unlock(&buffer_mutex);
@@ -150,8 +160,9 @@ static void on_process(void *userdata) {
__sync_synchronize();
}
static const struct pw_stream_events stream_events = {
PW_VERSION_STREAM_EVENTS, .process = on_process, .state_changed = on_state_changed};
static const struct pw_stream_events stream_events = {PW_VERSION_STREAM_EVENTS,
.process = on_process};
// PW_VERSION_STREAM_EVENTS, .process = on_process, .state_changed = on_state_changed};
static void deinit(void) {
pw_thread_loop_stop(data.loop);
@@ -173,7 +184,6 @@ static int init(__attribute__((unused)) int argc, __attribute__((unused)) char *
config.audio_backend_latency_offset = 0;
// get settings from settings file
// do the "general" audio options. Note, these options are in the "general" stanza!
parse_general_audio_options();
@@ -188,10 +198,12 @@ static int init(__attribute__((unused)) int argc, __attribute__((unused)) char *
// allocate space for the audio buffer
audio_lmb = malloc(audio_size);
if (audio_lmb == NULL)
die("Can't allocate %d bytes for pulseaudio buffer.", audio_size);
die("Can't allocate %d bytes for PipeWire buffer.", audio_size);
audio_toq = audio_eoq = audio_lmb;
audio_umb = audio_lmb + audio_size;
audio_occupancy = 0;
// debug(1, "init enable_fill");
enable_fill = 1;
const struct spa_pod *params[1];
uint8_t buffer[1024];
@@ -233,7 +245,8 @@ static int init(__attribute__((unused)) int argc, __attribute__((unused)) char *
}
static void start(__attribute__((unused)) int sample_rate,
__attribute__((unused)) int sample_format) {}
__attribute__((unused)) int sample_format) {
}
static int play(__attribute__((unused)) void *buf, int samples,
__attribute__((unused)) int sample_type, __attribute__((unused)) uint32_t timestamp,
@@ -322,6 +335,10 @@ static void flush(void) {
audio_toq = audio_eoq = audio_lmb;
audio_umb = audio_lmb + audio_size;
audio_occupancy = 0;
// if (enable_fill == 0) {
// debug(1, "flush enable_fill");
// }
enable_fill = 1;
pthread_mutex_unlock(&buffer_mutex);
}
@@ -330,6 +347,10 @@ static void stop(void) {
audio_toq = audio_eoq = audio_lmb;
audio_umb = audio_lmb + audio_size;
audio_occupancy = 0;
// if (enable_fill == 0) {
// debug(1, "stop enable_fill");
// }
enable_fill = 1;
pthread_mutex_unlock(&buffer_mutex);
}