mpv/libmpdemux/ai_alsa.c

124 lines
3.9 KiB
C
Raw Normal View History

#include "config.h"
#ifdef HAVE_ALSA9
#include <alsa/asoundlib.h>
#include "audio_in.h"
#include "mp_msg.h"
int ai_alsa_setup(audio_in_t *ai)
{
snd_pcm_hw_params_t *params;
snd_pcm_sw_params_t *swparams;
size_t buffer_size;
int err;
size_t n;
unsigned int rate;
snd_pcm_uframes_t start_threshold, stop_threshold;
snd_pcm_hw_params_alloca(&params);
snd_pcm_sw_params_alloca(&swparams);
err = snd_pcm_hw_params_any(ai->alsa.handle, params);
if (err < 0) {
mp_msg(MSGT_TV, MSGL_ERR, "Broken configuration for this PCM: no configurations available\n");
return -1;
}
err = snd_pcm_hw_params_set_access(ai->alsa.handle, params,
SND_PCM_ACCESS_RW_INTERLEAVED);
if (err < 0) {
mp_msg(MSGT_TV, MSGL_ERR, "Access type not available\n");
return -1;
}
err = snd_pcm_hw_params_set_format(ai->alsa.handle, params, SND_PCM_FORMAT_S16_LE);
if (err < 0) {
mp_msg(MSGT_TV, MSGL_ERR, "Sample format not available\n");
return -1;
}
err = snd_pcm_hw_params_set_channels(ai->alsa.handle, params, ai->req_channels);
if (err < 0) {
ai->channels = snd_pcm_hw_params_get_channels(params);
mp_msg(MSGT_TV, MSGL_ERR, "Channel count not available - reverting to default: %d\n",
ai->channels);
} else {
ai->channels = ai->req_channels;
}
err = snd_pcm_hw_params_set_rate_near(ai->alsa.handle, params, ai->req_samplerate, 0);
assert(err >= 0);
rate = err;
ai->samplerate = rate;
ai->alsa.buffer_time = 1000000;
ai->alsa.buffer_time = snd_pcm_hw_params_set_buffer_time_near(ai->alsa.handle, params,
ai->alsa.buffer_time, 0);
assert(ai->alsa.buffer_time >= 0);
ai->alsa.period_time = ai->alsa.buffer_time / 4;
ai->alsa.period_time = snd_pcm_hw_params_set_period_time_near(ai->alsa.handle, params,
ai->alsa.period_time, 0);
assert(ai->alsa.period_time >= 0);
err = snd_pcm_hw_params(ai->alsa.handle, params);
if (err < 0) {
mp_msg(MSGT_TV, MSGL_ERR, "Unable to install hw params:");
snd_pcm_hw_params_dump(params, ai->alsa.log);
return -1;
}
ai->alsa.chunk_size = snd_pcm_hw_params_get_period_size(params, 0);
buffer_size = snd_pcm_hw_params_get_buffer_size(params);
if (ai->alsa.chunk_size == buffer_size) {
mp_msg(MSGT_TV, MSGL_ERR, "Can't use period equal to buffer size (%u == %lu)\n", ai->alsa.chunk_size, (long)buffer_size);
return -1;
}
snd_pcm_sw_params_current(ai->alsa.handle, swparams);
err = snd_pcm_sw_params_set_sleep_min(ai->alsa.handle, swparams,0);
assert(err >= 0);
err = snd_pcm_sw_params_set_avail_min(ai->alsa.handle, swparams, ai->alsa.chunk_size);
assert(err >= 0);
err = snd_pcm_sw_params_set_start_threshold(ai->alsa.handle, swparams, 0);
assert(err >= 0);
err = snd_pcm_sw_params_set_stop_threshold(ai->alsa.handle, swparams, buffer_size);
assert(err >= 0);
assert(err >= 0);
if (snd_pcm_sw_params(ai->alsa.handle, swparams) < 0) {
mp_msg(MSGT_TV, MSGL_ERR, "unable to install sw params:\n");
snd_pcm_sw_params_dump(swparams, ai->alsa.log);
return -1;
}
if (mp_msg_test(MSGT_TV, MSGL_V)) {
snd_pcm_dump(ai->alsa.handle, ai->alsa.log);
}
ai->alsa.bits_per_sample = snd_pcm_format_physical_width(SND_PCM_FORMAT_S16_LE);
ai->alsa.bits_per_frame = ai->alsa.bits_per_sample * ai->channels;
ai->blocksize = ai->alsa.chunk_size * ai->alsa.bits_per_frame / 8;
ai->samplesize = ai->alsa.bits_per_sample;
ai->bytes_per_sample = ai->alsa.bits_per_sample/8;
return 0;
}
int ai_alsa_init(audio_in_t *ai)
{
int err;
err = snd_pcm_open(&ai->alsa.handle, ai->alsa.device, SND_PCM_STREAM_CAPTURE, 0);
if (err < 0) {
mp_msg(MSGT_TV, MSGL_ERR, "Error opening audio: %s\n", snd_strerror(err));
return -1;
}
err = snd_output_stdio_attach(&ai->alsa.log, stderr, 0);
if (err < 0) {
return -1;
}
err = ai_alsa_setup(ai);
return err;
}
#endif /* HAVE_ALSA9 */