mpv/audio/out/push.c

571 lines
17 KiB
C

/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stddef.h>
#include <pthread.h>
#include <inttypes.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
#include "osdep/io.h"
#include "ao.h"
#include "internal.h"
#include "audio/format.h"
#include "common/msg.h"
#include "common/common.h"
#include "input/input.h"
#include "osdep/threads.h"
#include "osdep/timer.h"
#include "osdep/atomic.h"
#include "audio/audio_buffer.h"
struct ao_push_state {
pthread_t thread;
pthread_mutex_t lock;
pthread_cond_t wakeup;
// --- protected by lock
struct mp_audio_buffer *buffer;
uint8_t *silence[MP_NUM_CHANNELS];
int silence_samples;
bool terminate;
bool wait_on_ao;
bool still_playing;
bool need_wakeup;
bool paused;
bool initial_unblocked;
// Whether the current buffer contains the complete audio.
bool final_chunk;
double expected_end_time;
int wakeup_pipe[2];
};
// lock must be held
static void wakeup_playthread(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
if (ao->driver->wakeup)
ao->driver->wakeup(ao);
p->need_wakeup = true;
pthread_cond_signal(&p->wakeup);
}
static int control(struct ao *ao, enum aocontrol cmd, void *arg)
{
int r = CONTROL_UNKNOWN;
if (ao->driver->control) {
struct ao_push_state *p = ao->api_priv;
pthread_mutex_lock(&p->lock);
r = ao->driver->control(ao, cmd, arg);
pthread_mutex_unlock(&p->lock);
}
return r;
}
static double unlocked_get_delay(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
double driver_delay = 0;
if (ao->driver->get_delay)
driver_delay = ao->driver->get_delay(ao);
return driver_delay + mp_audio_buffer_seconds(p->buffer);
}
static double get_delay(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
pthread_mutex_lock(&p->lock);
double delay = unlocked_get_delay(ao);
pthread_mutex_unlock(&p->lock);
return delay;
}
static void reset(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
pthread_mutex_lock(&p->lock);
if (ao->driver->reset)
ao->driver->reset(ao);
mp_audio_buffer_clear(p->buffer);
p->paused = false;
if (p->still_playing)
wakeup_playthread(ao);
p->still_playing = false;
pthread_mutex_unlock(&p->lock);
}
static void audio_pause(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
pthread_mutex_lock(&p->lock);
if (ao->driver->pause)
ao->driver->pause(ao);
p->paused = true;
wakeup_playthread(ao);
pthread_mutex_unlock(&p->lock);
}
static void resume(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
pthread_mutex_lock(&p->lock);
if (ao->driver->resume)
ao->driver->resume(ao);
p->paused = false;
p->expected_end_time = 0;
wakeup_playthread(ao);
pthread_mutex_unlock(&p->lock);
}
static void drain(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
double maxbuffer = ao->buffer / (double)ao->samplerate + 1;
MP_VERBOSE(ao, "draining...\n");
pthread_mutex_lock(&p->lock);
if (p->paused)
goto done;
p->final_chunk = true;
wakeup_playthread(ao);
// Wait until everything is done. Since the audio API (especially ALSA)
// can't be trusted to do this right, and we're hard-blocking here, apply
// an upper bound timeout.
struct timespec until = mp_rel_time_to_timespec(maxbuffer);
while (p->still_playing && mp_audio_buffer_samples(p->buffer) > 0) {
if (pthread_cond_timedwait(&p->wakeup, &p->lock, &until)) {
MP_WARN(ao, "Draining is taking too long, aborting.\n");
goto done;
}
}
if (ao->driver->drain) {
ao->driver->drain(ao);
} else {
double time = unlocked_get_delay(ao);
mp_sleep_us(MPMIN(time, maxbuffer) * 1e6);
}
done:
pthread_mutex_unlock(&p->lock);
reset(ao);
}
static int unlocked_get_space(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
int space = mp_audio_buffer_get_write_available(p->buffer);
if (ao->driver->get_space) {
int align = af_format_sample_alignment(ao->format);
// The following code attempts to keep the total buffered audio to
// ao->buffer in order to improve latency.
int device_space = ao->driver->get_space(ao);
int device_buffered = ao->device_buffer - device_space;
int soft_buffered = mp_audio_buffer_samples(p->buffer);
// The extra margin helps avoiding too many wakeups if the AO is fully
// byte based and doesn't do proper chunked processing.
int min_buffer = ao->buffer + 64;
int missing = min_buffer - device_buffered - soft_buffered;
missing = (missing + align - 1) / align * align;
// But always keep the device's buffer filled as much as we can.
int device_missing = device_space - soft_buffered;
missing = MPMAX(missing, device_missing);
space = MPMIN(space, missing);
space = MPMAX(0, space);
}
return space;
}
static int get_space(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
pthread_mutex_lock(&p->lock);
int space = unlocked_get_space(ao);
pthread_mutex_unlock(&p->lock);
return space;
}
static bool get_eof(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
pthread_mutex_lock(&p->lock);
bool eof = !p->still_playing;
pthread_mutex_unlock(&p->lock);
return eof;
}
static int play(struct ao *ao, void **data, int samples, int flags)
{
struct ao_push_state *p = ao->api_priv;
pthread_mutex_lock(&p->lock);
int write_samples = mp_audio_buffer_get_write_available(p->buffer);
write_samples = MPMIN(write_samples, samples);
MP_TRACE(ao, "samples=%d flags=%d r=%d\n", samples, flags, write_samples);
if (write_samples < samples)
flags = flags & ~AOPLAY_FINAL_CHUNK;
bool is_final = flags & AOPLAY_FINAL_CHUNK;
mp_audio_buffer_append(p->buffer, data, samples);
bool got_data = write_samples > 0 || p->paused || p->final_chunk != is_final;
p->final_chunk = is_final;
p->paused = false;
if (got_data) {
p->still_playing = true;
p->expected_end_time = 0;
// If we don't have new data, the decoder thread basically promises it
// will send new data as soon as it's available.
wakeup_playthread(ao);
}
pthread_mutex_unlock(&p->lock);
return write_samples;
}
static bool realloc_silence(struct ao *ao, int samples)
{
struct ao_push_state *p = ao->api_priv;
if (samples <= 0 || !af_fmt_is_pcm(ao->format))
return false;
if (samples > p->silence_samples) {
talloc_free(p->silence[0]);
int bytes = af_fmt_to_bytes(ao->format) * samples * ao->channels.num;
p->silence[0] = talloc_size(p, bytes);
for (int n = 1; n < MP_NUM_CHANNELS; n++)
p->silence[n] = p->silence[0];
p->silence_samples = samples;
af_fill_silence(p->silence[0], bytes, ao->format);
}
return true;
}
// called locked
static void ao_play_data(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
int space = ao->driver->get_space(ao);
bool play_silence = p->paused || (ao->stream_silence && !p->still_playing);
space = MPMAX(space, 0);
if (space % ao->period_size)
MP_ERR(ao, "Audio device reports unaligned available buffer size.\n");
uint8_t **planes;
int samples;
if (play_silence) {
planes = p->silence;
samples = realloc_silence(ao, space) ? space : 0;
} else {
mp_audio_buffer_peek(p->buffer, &planes, &samples);
}
int max = samples;
if (samples > space)
samples = space;
int flags = 0;
if (p->final_chunk && samples == max) {
flags |= AOPLAY_FINAL_CHUNK;
} else {
samples = samples / ao->period_size * ao->period_size;
}
MP_STATS(ao, "start ao fill");
ao_post_process_data(ao, (void **)planes, samples);
int r = 0;
if (samples)
r = ao->driver->play(ao, (void **)planes, samples, flags);
MP_STATS(ao, "end ao fill");
if (r > samples) {
MP_ERR(ao, "Audio device returned nonsense value.\n");
r = samples;
} else if (r < 0) {
MP_ERR(ao, "Error writing audio to device.\n");
} else if (r != samples) {
MP_ERR(ao, "Audio device returned broken buffer state (sent %d samples, "
"got %d samples, %d period%s)!\n", samples, r,
ao->period_size, flags & AOPLAY_FINAL_CHUNK ? " final" : "");
}
r = MPMAX(r, 0);
// Probably can't copy the rest of the buffer due to period alignment.
bool stuck_eof = r <= 0 && space >= max && samples > 0;
if ((flags & AOPLAY_FINAL_CHUNK) && stuck_eof) {
MP_ERR(ao, "Audio output driver seems to ignore AOPLAY_FINAL_CHUNK.\n");
r = max;
}
if (!play_silence)
mp_audio_buffer_skip(p->buffer, r);
if (r > 0)
p->expected_end_time = 0;
// Nothing written, but more input data than space - this must mean the
// AO's get_space() doesn't do period alignment correctly.
bool stuck = r == 0 && max >= space && space > 0;
if (stuck)
MP_ERR(ao, "Audio output is reporting incorrect buffer status.\n");
// Wait until space becomes available. Also wait if we actually wrote data,
// so the AO wakes us up properly if it needs more data.
p->wait_on_ao = space == 0 || r > 0 || stuck;
p->still_playing |= r > 0 && !play_silence;
// If we just filled the AO completely (r == space), don't refill for a
// while. Prevents wakeup feedback with byte-granular AOs.
int needed = unlocked_get_space(ao);
bool more = needed >= (r == space ? ao->device_buffer / 4 : 1) && !stuck &&
!(flags & AOPLAY_FINAL_CHUNK);
if (more)
ao->wakeup_cb(ao->wakeup_ctx); // request more data
MP_TRACE(ao, "in=%d flags=%d space=%d r=%d wa/pl=%d/%d needed=%d more=%d\n",
max, flags, space, r, p->wait_on_ao, p->still_playing, needed, more);
}
static void *playthread(void *arg)
{
struct ao *ao = arg;
struct ao_push_state *p = ao->api_priv;
mpthread_set_name("ao");
pthread_mutex_lock(&p->lock);
while (!p->terminate) {
bool blocked = ao->driver->initially_blocked && !p->initial_unblocked;
bool playing = (!p->paused || ao->stream_silence) && !blocked;
if (playing)
ao_play_data(ao);
if (!p->need_wakeup) {
MP_STATS(ao, "start audio wait");
if (!p->wait_on_ao || !playing) {
// Avoid busy waiting, because the audio API will still report
// that it needs new data, even if we're not ready yet, or if
// get_space() decides that the amount of audio buffered in the
// device is enough, and p->buffer can be empty.
// The most important part is that the decoder is woken up, so
// that the decoder will wake up us in turn.
MP_TRACE(ao, "buffer inactive.\n");
bool was_playing = p->still_playing;
double timeout = -1;
if (p->still_playing && !p->paused && p->final_chunk &&
!mp_audio_buffer_samples(p->buffer))
{
double now = mp_time_sec();
if (!p->expected_end_time)
p->expected_end_time = now + unlocked_get_delay(ao);
if (p->expected_end_time < now) {
p->still_playing = false;
} else {
timeout = p->expected_end_time - now;
}
}
if (was_playing && !p->still_playing)
ao->wakeup_cb(ao->wakeup_ctx);
pthread_cond_signal(&p->wakeup); // for draining
if (p->still_playing && timeout > 0) {
struct timespec ts = mp_rel_time_to_timespec(timeout);
pthread_cond_timedwait(&p->wakeup, &p->lock, &ts);
} else {
pthread_cond_wait(&p->wakeup, &p->lock);
}
} else {
// Wait until the device wants us to write more data to it.
if (!ao->driver->wait || ao->driver->wait(ao, &p->lock) < 0) {
// Fallback to guessing.
double timeout = 0;
if (ao->driver->get_delay)
timeout = ao->driver->get_delay(ao);
timeout *= 0.25; // wake up if 25% played
if (!p->need_wakeup) {
struct timespec ts = mp_rel_time_to_timespec(timeout);
pthread_cond_timedwait(&p->wakeup, &p->lock, &ts);
}
}
}
MP_STATS(ao, "end audio wait");
}
p->need_wakeup = false;
}
pthread_mutex_unlock(&p->lock);
return NULL;
}
static void destroy_no_thread(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
ao->driver->uninit(ao);
for (int n = 0; n < 2; n++) {
int h = p->wakeup_pipe[n];
if (h >= 0)
close(h);
}
pthread_cond_destroy(&p->wakeup);
pthread_mutex_destroy(&p->lock);
}
static void uninit(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
pthread_mutex_lock(&p->lock);
p->terminate = true;
wakeup_playthread(ao);
pthread_mutex_unlock(&p->lock);
pthread_join(p->thread, NULL);
destroy_no_thread(ao);
}
static int init(struct ao *ao)
{
struct ao_push_state *p = ao->api_priv;
pthread_mutex_init(&p->lock, NULL);
pthread_cond_init(&p->wakeup, NULL);
mp_make_wakeup_pipe(p->wakeup_pipe);
if (ao->device_buffer <= 0) {
MP_FATAL(ao, "Couldn't probe device buffer size.\n");
goto err;
}
p->buffer = mp_audio_buffer_create(ao);
mp_audio_buffer_reinit_fmt(p->buffer, ao->format,
&ao->channels, ao->samplerate);
mp_audio_buffer_preallocate_min(p->buffer, ao->buffer);
if (pthread_create(&p->thread, NULL, playthread, ao))
goto err;
return 0;
err:
destroy_no_thread(ao);
return -1;
}
const struct ao_driver ao_api_push = {
.init = init,
.control = control,
.uninit = uninit,
.reset = reset,
.get_space = get_space,
.play = play,
.get_delay = get_delay,
.pause = audio_pause,
.resume = resume,
.drain = drain,
.get_eof = get_eof,
.priv_size = sizeof(struct ao_push_state),
};
// Must be called locked.
int ao_play_silence(struct ao *ao, int samples)
{
assert(ao->api == &ao_api_push);
struct ao_push_state *p = ao->api_priv;
if (!realloc_silence(ao, samples) || !ao->driver->play)
return 0;
return ao->driver->play(ao, (void **)p->silence, samples, 0);
}
void ao_unblock(struct ao *ao)
{
if (ao->api == &ao_api_push) {
struct ao_push_state *p = ao->api_priv;
pthread_mutex_lock(&p->lock);
p->need_wakeup = true;
p->initial_unblocked = true;
wakeup_playthread(ao);
pthread_cond_signal(&p->wakeup);
pthread_mutex_unlock(&p->lock);
}
}
#ifndef __MINGW32__
#include <poll.h>
#define MAX_POLL_FDS 20
// Call poll() for the given fds. This will extend the given fds with the
// wakeup pipe, so ao_wakeup_poll() will basically interrupt this function.
// Unlocks the lock temporarily.
// Returns <0 on error, 0 on success, 1 if the caller should return immediately.
int ao_wait_poll(struct ao *ao, struct pollfd *fds, int num_fds,
pthread_mutex_t *lock)
{
struct ao_push_state *p = ao->api_priv;
assert(ao->api == &ao_api_push);
assert(&p->lock == lock);
if (num_fds >= MAX_POLL_FDS || p->wakeup_pipe[0] < 0)
return -1;
struct pollfd p_fds[MAX_POLL_FDS];
memcpy(p_fds, fds, num_fds * sizeof(p_fds[0]));
p_fds[num_fds] = (struct pollfd){
.fd = p->wakeup_pipe[0],
.events = POLLIN,
};
pthread_mutex_unlock(&p->lock);
int r = poll(p_fds, num_fds + 1, -1);
r = r < 0 ? -errno : 0;
pthread_mutex_lock(&p->lock);
memcpy(fds, p_fds, num_fds * sizeof(fds[0]));
bool wakeup = false;
if (p_fds[num_fds].revents & POLLIN) {
wakeup = true;
// might "drown" some wakeups, but that's ok for our use-case
mp_flush_wakeup_pipe(p->wakeup_pipe[0]);
}
return (r >= 0 || r == -EINTR) ? wakeup : -1;
}
void ao_wakeup_poll(struct ao *ao)
{
assert(ao->api == &ao_api_push);
struct ao_push_state *p = ao->api_priv;
(void)write(p->wakeup_pipe[1], &(char){0}, 1);
}
#endif