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mpv/audio/out/ao_sdl.c
wm4 7221d96ba3 ao_sdl: make sure our buffer is always larger than what SDL requests
Assume obtained.samples contains the number of samples the SDL audio
callback will request at once. Then make sure ao.c will set the buffer
size at least to 3 times that value (or more).

Might help with bad SDL audio backends like ESD, which supposedly uses a
500ms buffer.
2014-03-10 22:56:23 +01:00

231 lines
6.5 KiB
C

/*
* audio output driver for SDL 1.2+
* Copyright (C) 2012 Rudolf Polzer <divVerent@xonotic.org>
*
* This file is part of mpv.
*
* 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 "config.h"
#include "audio/format.h"
#include "talloc.h"
#include "ao.h"
#include "internal.h"
#include "common/common.h"
#include "common/msg.h"
#include "options/m_option.h"
#include "osdep/timer.h"
#include <SDL.h>
struct priv
{
bool paused;
float buflen;
};
static void audio_callback(void *userdata, Uint8 *stream, int len)
{
struct ao *ao = userdata;
void *data[1] = {stream};
if (len % ao->sstride)
MP_ERR(ao, "SDL audio callback not sample aligned");
// Time this buffer will take, plus assume 1 period (1 callback invocation)
// fixed latency.
double delay = 2 * len / (double)ao->bps;
ao_read_data(ao, data, len / ao->sstride, mp_time_us() + 1000000LL * delay);
}
static void uninit(struct ao *ao)
{
struct priv *priv = ao->priv;
if (!priv)
return;
if (SDL_WasInit(SDL_INIT_AUDIO)) {
// make sure the callback exits
SDL_LockAudio();
// close audio device
SDL_QuitSubSystem(SDL_INIT_AUDIO);
}
}
static unsigned int ceil_power_of_two(unsigned int x)
{
int y = 1;
while (y < x)
y *= 2;
return y;
}
static int init(struct ao *ao)
{
if (SDL_WasInit(SDL_INIT_AUDIO)) {
MP_ERR(ao, "already initialized\n");
return -1;
}
struct priv *priv = ao->priv;
if (SDL_InitSubSystem(SDL_INIT_AUDIO)) {
if (!ao->probing)
MP_ERR(ao, "SDL_Init failed\n");
uninit(ao);
return -1;
}
struct mp_chmap_sel sel = {0};
mp_chmap_sel_add_waveext_def(&sel);
if (!ao_chmap_sel_adjust(ao, &sel, &ao->channels)) {
uninit(ao);
return -1;
}
ao->format = af_fmt_from_planar(ao->format);
SDL_AudioSpec desired, obtained;
switch (ao->format) {
case AF_FORMAT_U8: desired.format = AUDIO_U8; break;
case AF_FORMAT_S8: desired.format = AUDIO_S8; break;
case AF_FORMAT_U16_LE: desired.format = AUDIO_U16LSB; break;
case AF_FORMAT_U16_BE: desired.format = AUDIO_U16MSB; break;
default:
case AF_FORMAT_S16_LE: desired.format = AUDIO_S16LSB; break;
case AF_FORMAT_S16_BE: desired.format = AUDIO_S16MSB; break;
#ifdef AUDIO_S32LSB
case AF_FORMAT_S32_LE: desired.format = AUDIO_S32LSB; break;
#endif
#ifdef AUDIO_S32MSB
case AF_FORMAT_S32_BE: desired.format = AUDIO_S32MSB; break;
#endif
#ifdef AUDIO_F32LSB
case AF_FORMAT_FLOAT_LE: desired.format = AUDIO_F32LSB; break;
#endif
#ifdef AUDIO_F32MSB
case AF_FORMAT_FLOAT_BE: desired.format = AUDIO_F32MSB; break;
#endif
}
desired.freq = ao->samplerate;
desired.channels = ao->channels.num;
desired.samples = MPMIN(32768, ceil_power_of_two(ao->samplerate *
priv->buflen));
desired.callback = audio_callback;
desired.userdata = ao;
MP_VERBOSE(ao, "requested format: %d Hz, %d channels, %x, "
"buffer size: %d samples\n",
(int) desired.freq, (int) desired.channels,
(int) desired.format, (int) desired.samples);
obtained = desired;
if (SDL_OpenAudio(&desired, &obtained)) {
if (!ao->probing)
MP_ERR(ao, "could not open audio: %s\n", SDL_GetError());
uninit(ao);
return -1;
}
MP_VERBOSE(ao, "obtained format: %d Hz, %d channels, %x, "
"buffer size: %d samples\n",
(int) obtained.freq, (int) obtained.channels,
(int) obtained.format, (int) obtained.samples);
// The sample count is usually the number of samples the callback requests,
// which we assume is the period size. Normally, ao.c will allocate a large
// enough buffer. But in case the period size should be pathologically
// large, this will help.
ao->device_buffer = 3 * obtained.samples;
switch (obtained.format) {
case AUDIO_U8: ao->format = AF_FORMAT_U8; break;
case AUDIO_S8: ao->format = AF_FORMAT_S8; break;
case AUDIO_S16LSB: ao->format = AF_FORMAT_S16_LE; break;
case AUDIO_S16MSB: ao->format = AF_FORMAT_S16_BE; break;
case AUDIO_U16LSB: ao->format = AF_FORMAT_U16_LE; break;
case AUDIO_U16MSB: ao->format = AF_FORMAT_U16_BE; break;
#ifdef AUDIO_S32LSB
case AUDIO_S32LSB: ao->format = AF_FORMAT_S32_LE; break;
#endif
#ifdef AUDIO_S32MSB
case AUDIO_S32MSB: ao->format = AF_FORMAT_S32_BE; break;
#endif
#ifdef AUDIO_F32LSB
case AUDIO_F32LSB: ao->format = AF_FORMAT_FLOAT_LE; break;
#endif
#ifdef AUDIO_F32MSB
case AUDIO_F32MSB: ao->format = AF_FORMAT_FLOAT_BE; break;
#endif
default:
if (!ao->probing)
MP_ERR(ao, "could not find matching format\n");
uninit(ao);
return -1;
}
if (!ao_chmap_sel_get_def(ao, &sel, &ao->channels, obtained.channels)) {
uninit(ao);
return -1;
}
ao->samplerate = obtained.freq;
priv->paused = 1;
return 1;
}
static void pause(struct ao *ao)
{
struct priv *priv = ao->priv;
if (!priv->paused)
SDL_PauseAudio(SDL_TRUE);
priv->paused = 1;
}
static void resume(struct ao *ao)
{
struct priv *priv = ao->priv;
if (priv->paused)
SDL_PauseAudio(SDL_FALSE);
priv->paused = 0;
}
#define OPT_BASE_STRUCT struct priv
const struct ao_driver audio_out_sdl = {
.description = "SDL Audio",
.name = "sdl",
.init = init,
.uninit = uninit,
.pause = pause,
.resume = resume,
.priv_size = sizeof(struct priv),
.priv_defaults = &(const struct priv) {
.buflen = 0, // use SDL default
},
.options = (const struct m_option[]) {
OPT_FLOAT("buflen", buflen, 0),
{0}
},
};