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mpv/audio/out/ao_alsa.c

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/*
* ALSA 0.9.x-1.x audio output driver
*
* Copyright (C) 2004 Alex Beregszaszi
*
* modified for real ALSA 0.9.0 support by Zsolt Barat <joy@streamminister.de>
* additional AC-3 passthrough support by Andy Lo A Foe <andy@alsaplayer.org>
* 08/22/2002 iec958-init rewritten and merged with common init, zsolt
* 04/13/2004 merged with ao_alsa1.x, fixes provided by Jindrich Makovicka
* 04/25/2004 printfs converted to mp_msg, Zsolt.
*
* 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 <errno.h>
#include <sys/time.h>
#include <stdlib.h>
#include <stdarg.h>
#include <ctype.h>
#include <math.h>
#include <string.h>
#include <alloca.h>
#include "config.h"
#include "mpvcore/options.h"
#include "mpvcore/m_option.h"
#include "mpvcore/mp_msg.h"
#define ALSA_PCM_NEW_HW_PARAMS_API
#define ALSA_PCM_NEW_SW_PARAMS_API
#include <alsa/asoundlib.h>
#include "ao.h"
#include "audio/format.h"
#include "audio/reorder_ch.h"
struct priv {
snd_pcm_t *alsa;
snd_pcm_format_t alsa_fmt;
size_t bytes_per_sample;
int can_pause;
snd_pcm_sframes_t prepause_frames;
float delay_before_pause;
int buffersize;
int outburst;
int cfg_block;
char *cfg_device;
char *cfg_mixer_device;
char *cfg_mixer_name;
int cfg_mixer_index;
};
#define BUFFER_TIME 500000 // 0.5 s
#define FRAGCOUNT 16
#define CHECK_ALSA_ERROR(message) \
do { \
if (err < 0) { \
MP_ERR(ao, "%s: %s\n", (message), snd_strerror(err)); \
goto alsa_error; \
} \
} while (0)
static float get_delay(struct ao *ao);
static int play(struct ao *ao, void *data, int len, int flags);
static void uninit(struct ao *ao, bool immed);
static void alsa_error_handler(const char *file, int line, const char *function,
int err, const char *format, ...)
{
char tmp[0xc00];
va_list va;
va_start(va, format);
vsnprintf(tmp, sizeof tmp, format, va);
va_end(va);
if (err) {
mp_msg(MSGT_AO, MSGL_ERR, "alsa-lib: %s:%i:(%s) %s: %s\n",
file, line, function, tmp, snd_strerror(err));
} else {
mp_msg(MSGT_AO, MSGL_ERR, "alsa-lib: %s:%i:(%s) %s\n",
file, line, function, tmp);
}
}
/* to set/get/query special features/parameters */
static int control(struct ao *ao, enum aocontrol cmd, void *arg)
{
struct priv *p = ao->priv;
snd_mixer_t *handle = NULL;
switch (cmd) {
case AOCONTROL_GET_MUTE:
case AOCONTROL_SET_MUTE:
case AOCONTROL_GET_VOLUME:
case AOCONTROL_SET_VOLUME:
{
int err;
snd_mixer_elem_t *elem;
snd_mixer_selem_id_t *sid;
long pmin, pmax;
long get_vol, set_vol;
float f_multi;
if (AF_FORMAT_IS_IEC61937(ao->format))
return CONTROL_TRUE;
//allocate simple id
snd_mixer_selem_id_alloca(&sid);
//sets simple-mixer index and name
snd_mixer_selem_id_set_index(sid, p->cfg_mixer_index);
snd_mixer_selem_id_set_name(sid, p->cfg_mixer_name);
err = snd_mixer_open(&handle, 0);
CHECK_ALSA_ERROR("Mixer open error");
err = snd_mixer_attach(handle, p->cfg_mixer_device);
CHECK_ALSA_ERROR("Mixer attach error");
err = snd_mixer_selem_register(handle, NULL, NULL);
CHECK_ALSA_ERROR("Mixer register error");
err = snd_mixer_load(handle);
CHECK_ALSA_ERROR("Mixer load error");
elem = snd_mixer_find_selem(handle, sid);
if (!elem) {
MP_VERBOSE(ao, "Unable to find simple control '%s',%i.\n",
snd_mixer_selem_id_get_name(sid),
snd_mixer_selem_id_get_index(sid));
goto alsa_error;
}
snd_mixer_selem_get_playback_volume_range(elem, &pmin, &pmax);
f_multi = (100 / (float)(pmax - pmin));
switch (cmd) {
case AOCONTROL_SET_VOLUME: {
ao_control_vol_t *vol = arg;
set_vol = vol->left / f_multi + pmin + 0.5;
//setting channels
err = snd_mixer_selem_set_playback_volume
(elem, SND_MIXER_SCHN_FRONT_LEFT, set_vol);
CHECK_ALSA_ERROR("Error setting left channel");
MP_DBG(ao, "left=%li, ", set_vol);
set_vol = vol->right / f_multi + pmin + 0.5;
err = snd_mixer_selem_set_playback_volume
(elem, SND_MIXER_SCHN_FRONT_RIGHT, set_vol);
CHECK_ALSA_ERROR("Error setting right channel");
MP_DBG(ao, "right=%li, pmin=%li, pmax=%li, mult=%f\n",
set_vol, pmin, pmax,
f_multi);
break;
}
case AOCONTROL_GET_VOLUME: {
ao_control_vol_t *vol = arg;
snd_mixer_selem_get_playback_volume
(elem, SND_MIXER_SCHN_FRONT_LEFT, &get_vol);
vol->left = (get_vol - pmin) * f_multi;
snd_mixer_selem_get_playback_volume
(elem, SND_MIXER_SCHN_FRONT_RIGHT, &get_vol);
vol->right = (get_vol - pmin) * f_multi;
MP_DBG(ao, "left=%f, right=%f\n", vol->left, vol->right);
break;
}
case AOCONTROL_SET_MUTE: {
bool *mute = arg;
if (!snd_mixer_selem_has_playback_switch(elem))
goto alsa_error;
if (!snd_mixer_selem_has_playback_switch_joined(elem)) {
snd_mixer_selem_set_playback_switch
(elem, SND_MIXER_SCHN_FRONT_RIGHT, !*mute);
}
snd_mixer_selem_set_playback_switch
(elem, SND_MIXER_SCHN_FRONT_LEFT, !*mute);
break;
}
case AOCONTROL_GET_MUTE: {
bool *mute = arg;
if (!snd_mixer_selem_has_playback_switch(elem))
goto alsa_error;
int tmp = 1;
snd_mixer_selem_get_playback_switch
(elem, SND_MIXER_SCHN_FRONT_LEFT, &tmp);
*mute = !tmp;
if (!snd_mixer_selem_has_playback_switch_joined(elem)) {
snd_mixer_selem_get_playback_switch
(elem, SND_MIXER_SCHN_FRONT_RIGHT, &tmp);
*mute &= !tmp;
}
break;
}
}
snd_mixer_close(handle);
return CONTROL_OK;
}
} //end switch
return CONTROL_UNKNOWN;
alsa_error:
if (handle)
snd_mixer_close(handle);
return CONTROL_ERROR;
}
static const int mp_to_alsa_format[][2] = {
{AF_FORMAT_S8, SND_PCM_FORMAT_S8},
{AF_FORMAT_U8, SND_PCM_FORMAT_U8},
{AF_FORMAT_U16_LE, SND_PCM_FORMAT_U16_LE},
{AF_FORMAT_U16_BE, SND_PCM_FORMAT_U16_BE},
{AF_FORMAT_S16_LE, SND_PCM_FORMAT_S16_LE},
{AF_FORMAT_S16_BE, SND_PCM_FORMAT_S16_BE},
{AF_FORMAT_U32_LE, SND_PCM_FORMAT_U32_LE},
{AF_FORMAT_U32_BE, SND_PCM_FORMAT_U32_BE},
{AF_FORMAT_S32_LE, SND_PCM_FORMAT_S32_LE},
{AF_FORMAT_S32_BE, SND_PCM_FORMAT_S32_BE},
{AF_FORMAT_U24_LE, SND_PCM_FORMAT_U24_3LE},
{AF_FORMAT_U24_BE, SND_PCM_FORMAT_U24_3BE},
{AF_FORMAT_S24_LE, SND_PCM_FORMAT_S24_3LE},
{AF_FORMAT_S24_BE, SND_PCM_FORMAT_S24_3BE},
{AF_FORMAT_FLOAT_LE, SND_PCM_FORMAT_FLOAT_LE},
{AF_FORMAT_FLOAT_BE, SND_PCM_FORMAT_FLOAT_BE},
{AF_FORMAT_AC3_LE, SND_PCM_FORMAT_S16_LE},
{AF_FORMAT_AC3_BE, SND_PCM_FORMAT_S16_BE},
{AF_FORMAT_IEC61937_LE, SND_PCM_FORMAT_S16_LE},
{AF_FORMAT_IEC61937_BE, SND_PCM_FORMAT_S16_BE},
{AF_FORMAT_MPEG2, SND_PCM_FORMAT_MPEG},
{AF_FORMAT_UNKNOWN, SND_PCM_FORMAT_UNKNOWN},
};
static int find_alsa_format(int af_format)
{
for (int n = 0; mp_to_alsa_format[n][0] != AF_FORMAT_UNKNOWN; n++) {
if (mp_to_alsa_format[n][0] == af_format)
return mp_to_alsa_format[n][1];
}
return SND_PCM_FORMAT_UNKNOWN;
}
// Lists device names and their implied channel map.
// The second item must be resolvable with mp_chmap_from_str().
// Source: http://www.alsa-project.org/main/index.php/DeviceNames
// (Speaker names are slightly different from mpv's.)
static const char *device_channel_layouts[][2] = {
{"default", "fc"},
{"default", "fl-fr"},
{"rear", "bl-br"},
{"center_lfe", "fc-lfe"},
{"side", "sl-sr"},
{"surround40", "fl-fr-bl-br"},
{"surround50", "fl-fr-bl-br-fc"},
{"surround41", "fl-fr-bl-br-lfe"},
{"surround51", "fl-fr-bl-br-fc-lfe"},
{"surround71", "fl-fr-bl-br-fc-lfe-sl-sr"},
};
#define ARRAY_LEN(x) (sizeof(x) / sizeof((x)[0]))
#define NUM_ALSA_CHMAPS ARRAY_LEN(device_channel_layouts)
static const char *select_chmap(struct ao *ao)
{
struct mp_chmap_sel sel = {0};
struct mp_chmap maps[NUM_ALSA_CHMAPS];
for (int n = 0; n < NUM_ALSA_CHMAPS; n++) {
mp_chmap_from_str(&maps[n], bstr0(device_channel_layouts[n][1]));
mp_chmap_sel_add_map(&sel, &maps[n]);
};
if (!ao_chmap_sel_adjust(ao, &sel, &ao->channels))
return NULL;
for (int n = 0; n < NUM_ALSA_CHMAPS; n++) {
if (mp_chmap_equals(&ao->channels, &maps[n]))
return device_channel_layouts[n][0];
}
char *name = mp_chmap_to_str(&ao->channels);
MP_ERR(ao, "channel layout %s (%d ch) not supported.\n",
name, ao->channels.num);
talloc_free(name);
return "default";
}
static int try_open_device(struct ao *ao, const char *device, int open_mode,
int try_ac3)
{
struct priv *p = ao->priv;
int err, len;
char *ac3_device, *args;
if (try_ac3) {
/* to set the non-audio bit, use AES0=6 */
len = strlen(device);
ac3_device = malloc(len + 7 + 1);
if (!ac3_device)
return -ENOMEM;
strcpy(ac3_device, device);
args = strchr(ac3_device, ':');
if (!args) {
/* no existing parameters: add it behind device name */
strcat(ac3_device, ":AES0=6");
} else {
do {
++args;
} while (isspace(*args));
if (*args == '\0') {
/* ":" but no parameters */
strcat(ac3_device, "AES0=6");
} else if (*args != '{') {
/* a simple list of parameters: add it at the end of the list */
strcat(ac3_device, ",AES0=6");
} else {
/* parameters in config syntax: add it inside the { } block */
do {
--len;
} while (len > 0 && isspace(ac3_device[len]));
if (ac3_device[len] == '}')
strcpy(ac3_device + len, " AES0=6}");
}
}
err = snd_pcm_open
(&p->alsa, ac3_device, SND_PCM_STREAM_PLAYBACK, open_mode);
free(ac3_device);
if (!err)
return 0;
}
return snd_pcm_open
(&p->alsa, device, SND_PCM_STREAM_PLAYBACK, open_mode);
}
/*
open & setup audio device
return: 0=success -1=fail
*/
static int init(struct ao *ao)
{
int err;
snd_pcm_uframes_t chunk_size;
snd_pcm_uframes_t bufsize;
snd_pcm_uframes_t boundary;
struct priv *p = ao->priv;
MP_VERBOSE(ao, "requested format: %d Hz, %d channels, %x\n",
ao->samplerate, ao->channels.num, ao->format);
p->prepause_frames = 0;
p->delay_before_pause = 0;
/* switch for spdif
* sets opening sequence for SPDIF
* sets also the playback and other switches 'on the fly'
* while opening the abstract alias for the spdif subdevice
* 'iec958'
*/
const char *device;
if (AF_FORMAT_IS_IEC61937(ao->format)) {
device = "iec958";
MP_VERBOSE(ao, "playing AC3/iec61937/iec958, %i channels\n",
ao->channels.num);
} else {
device = select_chmap(ao);
if (strcmp(device, "default") != 0 && ao->format == AF_FORMAT_FLOAT_NE)
{
// hack - use the converter plugin (why the heck?)
device = talloc_asprintf(ao, "plug:%s", device);
}
}
if (p->cfg_device && p->cfg_device[0])
device = p->cfg_device;
MP_VERBOSE(ao, "using device: %s\n", device);
p->can_pause = 1;
MP_VERBOSE(ao, "using ALSA version: %s\n", snd_asoundlib_version());
snd_lib_error_set_handler(alsa_error_handler);
int open_mode = p->cfg_block ? 0 : SND_PCM_NONBLOCK;
int isac3 = AF_FORMAT_IS_IEC61937(ao->format);
//modes = 0, SND_PCM_NONBLOCK, SND_PCM_ASYNC
err = try_open_device(ao, device, open_mode, isac3);
if (err < 0) {
if (err != -EBUSY && !p->cfg_block) {
MP_WARN(ao, "Open in nonblock-mode "
"failed, trying to open in block-mode.\n");
err = try_open_device(ao, device, 0, isac3);
}
CHECK_ALSA_ERROR("Playback open error");
}
err = snd_pcm_nonblock(p->alsa, 0);
if (err < 0) {
MP_ERR(ao, "Error setting block-mode: %s.\n", snd_strerror(err));
} else {
MP_VERBOSE(ao, "pcm opened in blocking mode\n");
}
snd_pcm_hw_params_t *alsa_hwparams;
snd_pcm_sw_params_t *alsa_swparams;
snd_pcm_hw_params_alloca(&alsa_hwparams);
snd_pcm_sw_params_alloca(&alsa_swparams);
// setting hw-parameters
err = snd_pcm_hw_params_any(p->alsa, alsa_hwparams);
CHECK_ALSA_ERROR("Unable to get initial parameters");
err = snd_pcm_hw_params_set_access
(p->alsa, alsa_hwparams, SND_PCM_ACCESS_RW_INTERLEAVED);
CHECK_ALSA_ERROR("Unable to set access type");
p->alsa_fmt = find_alsa_format(ao->format);
if (p->alsa_fmt == SND_PCM_FORMAT_UNKNOWN) {
p->alsa_fmt = SND_PCM_FORMAT_S16;
ao->format = AF_FORMAT_S16_NE;
}
err = snd_pcm_hw_params_test_format(p->alsa, alsa_hwparams, p->alsa_fmt);
if (err < 0) {
MP_INFO(ao, "Format %s is not supported by hardware, trying default.\n",
af_fmt2str_short(ao->format));
p->alsa_fmt = SND_PCM_FORMAT_S16_LE;
if (AF_FORMAT_IS_AC3(ao->format))
ao->format = AF_FORMAT_AC3_LE;
else if (AF_FORMAT_IS_IEC61937(ao->format))
ao->format = AF_FORMAT_IEC61937_LE;
else
ao->format = AF_FORMAT_S16_LE;
}
err = snd_pcm_hw_params_set_format(p->alsa, alsa_hwparams, p->alsa_fmt);
CHECK_ALSA_ERROR("Unable to set format");
int num_channels = ao->channels.num;
err = snd_pcm_hw_params_set_channels_near
(p->alsa, alsa_hwparams, &num_channels);
CHECK_ALSA_ERROR("Unable to set channels");
if (num_channels != ao->channels.num) {
MP_ERR(ao, "Couldn't get requested number of channels.\n");
mp_chmap_from_channels_alsa(&ao->channels, num_channels);
}
/* workaround for buggy rate plugin (should be fixed in ALSA 1.0.11)
prefer our own resampler, since that allows users to choose the resampler,
even per file if desired */
err = snd_pcm_hw_params_set_rate_resample(p->alsa, alsa_hwparams, 0);
CHECK_ALSA_ERROR("Unable to disable resampling");
err = snd_pcm_hw_params_set_rate_near
(p->alsa, alsa_hwparams, &ao->samplerate, NULL);
CHECK_ALSA_ERROR("Unable to set samplerate-2");
p->bytes_per_sample = af_fmt2bits(ao->format) / 8;
p->bytes_per_sample *= ao->channels.num;
err = snd_pcm_hw_params_set_buffer_time_near
(p->alsa, alsa_hwparams, &(unsigned int){BUFFER_TIME}, NULL);
CHECK_ALSA_ERROR("Unable to set buffer time near");
err = snd_pcm_hw_params_set_periods_near
(p->alsa, alsa_hwparams, &(unsigned int){FRAGCOUNT}, NULL);
CHECK_ALSA_ERROR("Unable to set periods");
/* finally install hardware parameters */
err = snd_pcm_hw_params(p->alsa, alsa_hwparams);
CHECK_ALSA_ERROR("Unable to set hw-parameters");
// end setting hw-params
// gets buffersize for control
err = snd_pcm_hw_params_get_buffer_size(alsa_hwparams, &bufsize);
CHECK_ALSA_ERROR("Unable to get buffersize");
p->buffersize = bufsize * p->bytes_per_sample;
MP_VERBOSE(ao, "got buffersize=%i\n", p->buffersize);
err = snd_pcm_hw_params_get_period_size(alsa_hwparams, &chunk_size, NULL);
CHECK_ALSA_ERROR("Unable to get period size");
MP_VERBOSE(ao, "got period size %li\n", chunk_size);
p->outburst = chunk_size * p->bytes_per_sample;
/* setting software parameters */
err = snd_pcm_sw_params_current(p->alsa, alsa_swparams);
CHECK_ALSA_ERROR("Unable to get sw-parameters");
err = snd_pcm_sw_params_get_boundary(alsa_swparams, &boundary);
CHECK_ALSA_ERROR("Unable to get boundary");
/* start playing when one period has been written */
err = snd_pcm_sw_params_set_start_threshold
(p->alsa, alsa_swparams, chunk_size);
CHECK_ALSA_ERROR("Unable to set start threshold");
/* disable underrun reporting */
err = snd_pcm_sw_params_set_stop_threshold
(p->alsa, alsa_swparams, boundary);
CHECK_ALSA_ERROR("Unable to set stop threshold");
/* play silence when there is an underrun */
err = snd_pcm_sw_params_set_silence_size
(p->alsa, alsa_swparams, boundary);
CHECK_ALSA_ERROR("Unable to set silence size");
err = snd_pcm_sw_params(p->alsa, alsa_swparams);
CHECK_ALSA_ERROR("Unable to get sw-parameters");
/* end setting sw-params */
p->can_pause = snd_pcm_hw_params_can_pause(alsa_hwparams);
MP_VERBOSE(ao, "opened: %d Hz/%d channels/%d bpf/%d bytes buffer/%s\n",
ao->samplerate, ao->channels.num, (int)p->bytes_per_sample,
p->buffersize, snd_pcm_format_description(p->alsa_fmt));
return 0;
alsa_error:
uninit(ao, true);
return -1;
} // end init
/* close audio device */
static void uninit(struct ao *ao, bool immed)
{
struct priv *p = ao->priv;
if (p->alsa) {
int err;
if (!immed)
snd_pcm_drain(p->alsa);
err = snd_pcm_close(p->alsa);
CHECK_ALSA_ERROR("pcm close error");
MP_VERBOSE(ao, "uninit: pcm closed\n");
}
alsa_error:
p->alsa = NULL;
snd_lib_error_set_handler(NULL);
}
static void audio_pause(struct ao *ao)
{
struct priv *p = ao->priv;
int err;
if (p->can_pause) {
p->delay_before_pause = get_delay(ao);
err = snd_pcm_pause(p->alsa, 1);
CHECK_ALSA_ERROR("pcm pause error");
} else {
MP_VERBOSE(ao, "pause not supported by hardware\n");
if (snd_pcm_delay(p->alsa, &p->prepause_frames) < 0
|| p->prepause_frames < 0)
p->prepause_frames = 0;
p->delay_before_pause = p->prepause_frames / (float)ao->samplerate;
err = snd_pcm_drop(p->alsa);
CHECK_ALSA_ERROR("pcm drop error");
}
alsa_error: ;
}
static void audio_resume(struct ao *ao)
{
struct priv *p = ao->priv;
int err;
if (snd_pcm_state(p->alsa) == SND_PCM_STATE_SUSPENDED) {
MP_INFO(ao, "PCM in suspend mode, trying to resume.\n");
while ((err = snd_pcm_resume(p->alsa)) == -EAGAIN)
sleep(1);
}
if (p->can_pause) {
err = snd_pcm_pause(p->alsa, 0);
CHECK_ALSA_ERROR("pcm resume error");
} else {
MP_VERBOSE(ao, "resume not supported by hardware\n");
err = snd_pcm_prepare(p->alsa);
CHECK_ALSA_ERROR("pcm prepare error");
if (p->prepause_frames) {
void *silence = calloc(p->prepause_frames, p->bytes_per_sample);
play(ao, silence, p->prepause_frames * p->bytes_per_sample, 0);
free(silence);
}
}
alsa_error: ;
}
/* stop playing and empty buffers (for seeking/pause) */
static void reset(struct ao *ao)
{
struct priv *p = ao->priv;
int err;
p->prepause_frames = 0;
p->delay_before_pause = 0;
err = snd_pcm_drop(p->alsa);
CHECK_ALSA_ERROR("pcm prepare error");
err = snd_pcm_prepare(p->alsa);
CHECK_ALSA_ERROR("pcm prepare error");
alsa_error: ;
}
/*
plays 'len' bytes of 'data'
returns: number of bytes played
modified last at 29.06.02 by jp
thanxs for marius <marius@rospot.com> for giving us the light ;)
*/
static int play(struct ao *ao, void *data, int len, int flags)
{
struct priv *p = ao->priv;
int num_frames;
snd_pcm_sframes_t res = 0;
if (!(flags & AOPLAY_FINAL_CHUNK))
len = len / p->outburst * p->outburst;
num_frames = len / p->bytes_per_sample;
if (!p->alsa) {
MP_ERR(ao, "Device configuration error.");
return 0;
}
if (num_frames == 0)
return 0;
do {
res = snd_pcm_writei(p->alsa, data, num_frames);
if (res == -EINTR) {
/* nothing to do */
res = 0;
} else if (res == -ESTRPIPE) { /* suspend */
MP_INFO(ao, "PCM in suspend mode, trying to resume.\n");
while ((res = snd_pcm_resume(p->alsa)) == -EAGAIN)
sleep(1);
}
if (res < 0) {
MP_ERR(ao, "Write error: %s\n", snd_strerror(res));
res = snd_pcm_prepare(p->alsa);
int err = res;
CHECK_ALSA_ERROR("pcm prepare error");
res = 0;
}
} while (res == 0);
return res < 0 ? 0 : res * p->bytes_per_sample;
alsa_error:
return 0;
}
/* how many byes are free in the buffer */
static int get_space(struct ao *ao)
{
struct priv *p = ao->priv;
snd_pcm_status_t *status;
int err;
snd_pcm_status_alloca(&status);
err = snd_pcm_status(p->alsa, status);
CHECK_ALSA_ERROR("cannot get pcm status");
unsigned space = snd_pcm_status_get_avail(status) * p->bytes_per_sample;
if (space > p->buffersize) // Buffer underrun?
space = p->buffersize;
return space;
alsa_error:
return 0;
}
/* delay in seconds between first and last sample in buffer */
static float get_delay(struct ao *ao)
{
struct priv *p = ao->priv;
if (p->alsa) {
snd_pcm_sframes_t delay;
if (snd_pcm_state(p->alsa) == SND_PCM_STATE_PAUSED)
return p->delay_before_pause;
if (snd_pcm_delay(p->alsa, &delay) < 0)
return 0;
if (delay < 0) {
/* underrun - move the application pointer forward to catch up */
snd_pcm_forward(p->alsa, -delay);
delay = 0;
}
return (float)delay / (float)ao->samplerate;
} else
return 0;
}
#define OPT_BASE_STRUCT struct priv
const struct ao_driver audio_out_alsa = {
.info = &(const struct ao_info) {
"ALSA-0.9.x-1.x audio output",
"alsa",
"Alex Beregszaszi, Zsolt Barat <joy@streamminister.de>",
"under development"
},
.init = init,
.uninit = uninit,
.control = control,
.get_space = get_space,
.play = play,
.get_delay = get_delay,
.pause = audio_pause,
.resume = audio_resume,
.reset = reset,
.priv_size = sizeof(struct priv),
.priv_defaults = &(const struct priv) {
.cfg_block = 1,
.cfg_mixer_device = "default",
.cfg_mixer_name = "Master",
.cfg_mixer_index = 0,
},
.options = (const struct m_option[]) {
OPT_STRING("device", cfg_device, 0),
OPT_FLAG("block", cfg_block, 0),
OPT_STRING("mixer-device", cfg_mixer_device, 0),
OPT_STRING("mixer-name", cfg_mixer_name, 0),
OPT_INTRANGE("mixer-index", cfg_mixer_index, 0, 0, 99),
{0}
},
};
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