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mpv/audio/out/ao.c
wm4 d842b017e4 audio/out: reduce amount of audio buffering
Since the addition of the AO feed thread, 200ms of latency (MIN_BUFFER)
was added to all push-based AOs. This is not so nice, because even AOs
with relatively small buffering (e.g. ao_alsa on my system with ~170ms
of buffer size), the additional latency becomes noticable when e.g.
toggling mute with softvol.

Fix this by trying to keep not only 200ms minimum buffer, but also 200ms
maximum buffer. In other words, never buffer beyond 200ms in total. Do
this by estimating the AO's buffer fill status using get_space and the
initially known AO buffer size (the get_space return value on
initialization, before any audio was played). We limit the maximum
amount of data written to the soft buffer so that soft buffer size and
audio buffer size equal to 200ms (MIN_BUFFER).

To avoid weird problems with weird AOs, we buffer beyond MIN_BUFFER if
the AO's get_space requests more data than that, and as long as the soft
buffer is large enough.

Note that this is just a hack to improve the latency. When the audio
chain gains the ability to refilter data, this won't be needed anymore,
and instead we can introduce some sort of buffer replacement function in
order to update data in the soft buffer.
2014-03-10 01:13:40 +01:00

368 lines
10 KiB
C

/*
* This file is part of MPlayer.
*
* MPlayer is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* MPlayer 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with MPlayer; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "talloc.h"
#include "config.h"
#include "ao.h"
#include "internal.h"
#include "audio/format.h"
#include "audio/audio.h"
#include "options/options.h"
#include "options/m_config.h"
#include "osdep/timer.h"
#include "common/msg.h"
#include "common/common.h"
#include "common/global.h"
extern const struct ao_driver audio_out_oss;
extern const struct ao_driver audio_out_coreaudio;
extern const struct ao_driver audio_out_rsound;
extern const struct ao_driver audio_out_sndio;
extern const struct ao_driver audio_out_pulse;
extern const struct ao_driver audio_out_jack;
extern const struct ao_driver audio_out_openal;
extern const struct ao_driver audio_out_null;
extern const struct ao_driver audio_out_alsa;
extern const struct ao_driver audio_out_dsound;
extern const struct ao_driver audio_out_wasapi;
extern const struct ao_driver audio_out_pcm;
extern const struct ao_driver audio_out_lavc;
extern const struct ao_driver audio_out_portaudio;
extern const struct ao_driver audio_out_sdl;
static const struct ao_driver * const audio_out_drivers[] = {
// native:
#if HAVE_COREAUDIO
&audio_out_coreaudio,
#endif
#if HAVE_PULSE
&audio_out_pulse,
#endif
#if HAVE_SNDIO
&audio_out_sndio,
#endif
#if HAVE_ALSA
&audio_out_alsa,
#endif
#if HAVE_WASAPI
&audio_out_wasapi,
#endif
#if HAVE_OSS_AUDIO
&audio_out_oss,
#endif
#if HAVE_DSOUND
&audio_out_dsound,
#endif
#if HAVE_PORTAUDIO
&audio_out_portaudio,
#endif
// wrappers:
#if HAVE_JACK
&audio_out_jack,
#endif
#if HAVE_OPENAL
&audio_out_openal,
#endif
#if HAVE_SDL1 || HAVE_SDL2
&audio_out_sdl,
#endif
&audio_out_null,
// should not be auto-selected:
&audio_out_pcm,
#if HAVE_ENCODING
&audio_out_lavc,
#endif
#if HAVE_RSOUND
&audio_out_rsound,
#endif
NULL
};
static bool get_desc(struct m_obj_desc *dst, int index)
{
if (index >= MP_ARRAY_SIZE(audio_out_drivers) - 1)
return false;
const struct ao_driver *ao = audio_out_drivers[index];
*dst = (struct m_obj_desc) {
.name = ao->name,
.description = ao->description,
.priv_size = ao->priv_size,
.priv_defaults = ao->priv_defaults,
.options = ao->options,
.hidden = ao->encode,
.p = ao,
};
return true;
}
// For the ao option
const struct m_obj_list ao_obj_list = {
.get_desc = get_desc,
.description = "audio outputs",
.allow_unknown_entries = true,
.allow_trailer = true,
};
static struct ao *ao_create(bool probing, struct mpv_global *global,
struct input_ctx *input_ctx,
struct encode_lavc_context *encode_lavc_ctx,
int samplerate, int format, struct mp_chmap channels,
char *name, char **args)
{
struct mp_log *log = mp_log_new(NULL, global->log, "ao");
struct m_obj_desc desc;
if (!m_obj_list_find(&desc, &ao_obj_list, bstr0(name))) {
mp_msg(log, MSGL_ERR, "Audio output %s not found!\n", name);
talloc_free(log);
return NULL;
};
struct ao *ao = talloc_ptrtype(NULL, ao);
talloc_steal(ao, log);
*ao = (struct ao) {
.driver = desc.p,
.probing = probing,
.encode_lavc_ctx = encode_lavc_ctx,
.input_ctx = input_ctx,
.samplerate = samplerate,
.channels = channels,
.format = format,
.log = mp_log_new(ao, log, name),
};
if (ao->driver->encode != !!ao->encode_lavc_ctx)
goto error;
struct m_config *config = m_config_from_obj_desc(ao, ao->log, &desc);
if (m_config_apply_defaults(config, name, global->opts->ao_defs) < 0)
goto error;
if (m_config_set_obj_params(config, args) < 0)
goto error;
ao->priv = config->optstruct;
char *chmap = mp_chmap_to_str(&ao->channels);
MP_VERBOSE(ao, "requested format: %d Hz, %s channels, %s\n",
ao->samplerate, chmap, af_fmt_to_str(ao->format));
talloc_free(chmap);
ao->api = ao->driver->play ? &ao_api_push : &ao_api_pull;
ao->api_priv = talloc_zero_size(ao, ao->api->priv_size);
assert(!ao->api->priv_defaults && !ao->api->options);
if (ao->driver->init(ao) < 0)
goto error;
ao->sstride = af_fmt2bits(ao->format) / 8;
ao->num_planes = 1;
if (af_fmt_is_planar(ao->format)) {
ao->num_planes = ao->channels.num;
} else {
ao->sstride *= ao->channels.num;
}
ao->bps = ao->samplerate * ao->sstride;
if (!ao->device_buffer && ao->driver->get_space)
ao->device_buffer = ao->driver->get_space(ao);
ao->buffer = MPMAX(ao->device_buffer, MIN_BUFFER * ao->samplerate);
MP_VERBOSE(ao, "using soft-buffer of %d samples.\n", ao->buffer);
if (ao->api->init(ao) < 0)
goto error;
return ao;
error:
talloc_free(ao);
return NULL;
}
struct ao *ao_init_best(struct mpv_global *global,
struct input_ctx *input_ctx,
struct encode_lavc_context *encode_lavc_ctx,
int samplerate, int format, struct mp_chmap channels)
{
struct mp_log *log = mp_log_new(NULL, global->log, "ao");
struct ao *ao = NULL;
struct m_obj_settings *ao_list = global->opts->audio_driver_list;
if (ao_list && ao_list[0].name) {
for (int n = 0; ao_list[n].name; n++) {
if (strlen(ao_list[n].name) == 0)
goto autoprobe;
mp_verbose(log, "Trying preferred audio driver '%s'\n",
ao_list[n].name);
ao = ao_create(false, global, input_ctx, encode_lavc_ctx,
samplerate, format, channels,
ao_list[n].name, ao_list[n].attribs);
if (ao)
goto done;
mp_warn(log, "Failed to initialize audio driver '%s'\n",
ao_list[n].name);
}
goto done;
}
autoprobe:
// now try the rest...
for (int i = 0; audio_out_drivers[i]; i++) {
ao = ao_create(true, global, input_ctx, encode_lavc_ctx,
samplerate, format, channels,
(char *)audio_out_drivers[i]->name, NULL);
if (ao)
goto done;
}
done:
talloc_free(log);
return ao;
}
// Uninitialize and destroy the AO. Remaining audio must be dropped.
void ao_uninit(struct ao *ao)
{
ao->api->uninit(ao);
talloc_free(ao);
}
// Queue the given audio data. Start playback if it hasn't started yet. Return
// the number of samples that was accepted (the core will try to queue the rest
// again later). Should never block.
// data: start pointer for each plane. If the audio data is packed, only
// data[0] is valid, otherwise there is a plane for each channel.
// samples: size of the audio data (see ao->sstride)
// flags: currently AOPLAY_FINAL_CHUNK can be set
int ao_play(struct ao *ao, void **data, int samples, int flags)
{
return ao->api->play(ao, data, samples, flags);
}
int ao_control(struct ao *ao, enum aocontrol cmd, void *arg)
{
switch (cmd) {
case AOCONTROL_HAS_TEMP_VOLUME:
return !ao->no_persistent_volume;
case AOCONTROL_HAS_PER_APP_VOLUME:
return !!ao->per_application_mixer;
default:
if (ao->api->control)
return ao->api->control(ao, cmd, arg);
}
return CONTROL_UNKNOWN;
}
// Return size of the buffered data in seconds. Can include the device latency.
// Basically, this returns how much data there is still to play, and how long
// it takes until the last sample in the buffer reaches the speakers. This is
// used for audio/video synchronization, so it's very important to implement
// this correctly.
double ao_get_delay(struct ao *ao)
{
if (!ao->api->get_delay) {
assert(ao->untimed);
return 0;
}
return ao->api->get_delay(ao);
}
// Return free size of the internal audio buffer. This controls how much audio
// the core should decode and try to queue with ao_play().
int ao_get_space(struct ao *ao)
{
return ao->api->get_space(ao);
}
// Stop playback and empty buffers. Essentially go back to the state after
// ao->init().
void ao_reset(struct ao *ao)
{
if (ao->api->reset)
ao->api->reset(ao);
}
// Pause playback. Keep the current buffer. ao_get_delay() must return the
// same value as before pausing.
void ao_pause(struct ao *ao)
{
if (ao->api->pause)
ao->api->pause(ao);
}
// Resume playback. Play the remaining buffer. If the driver doesn't support
// pausing, it has to work around this and e.g. use ao_play_silence() to fill
// the lost audio.
void ao_resume(struct ao *ao)
{
if (ao->api->resume)
ao->api->resume(ao);
}
// Be careful with locking
void ao_wait_drain(struct ao *ao)
{
// This is probably not entirely accurate, but good enough.
mp_sleep_us(ao_get_delay(ao) * 1000000);
ao_reset(ao);
}
// Block until the current audio buffer has played completely.
void ao_drain(struct ao *ao)
{
if (ao->api->drain) {
ao->api->drain(ao);
} else {
ao_wait_drain(ao);
}
}
bool ao_chmap_sel_adjust(struct ao *ao, const struct mp_chmap_sel *s,
struct mp_chmap *map)
{
return mp_chmap_sel_adjust(s, map);
}
bool ao_chmap_sel_get_def(struct ao *ao, const struct mp_chmap_sel *s,
struct mp_chmap *map, int num)
{
return mp_chmap_sel_get_def(s, map, num);
}
// --- The following functions just return immutable information.
void ao_get_format(struct ao *ao, struct mp_audio *format)
{
*format = (struct mp_audio){0};
mp_audio_set_format(format, ao->format);
mp_audio_set_channels(format, &ao->channels);
format->rate = ao->samplerate;
}
const char *ao_get_name(struct ao *ao)
{
return ao->driver->name;
}
const char *ao_get_description(struct ao *ao)
{
return ao->driver->description;
}
bool ao_untimed(struct ao *ao)
{
return ao->untimed;
}