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Complete non-blocking example

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Laurens Miers 2020-05-27 13:56:39 +02:00
parent 0960e3a025
commit 1f7904fab8
1 changed files with 7 additions and 13 deletions
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20
alsa_info.md
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@ -520,17 +520,20 @@ int main(int argc, char **argv)
int period_time = 0; int period_time = 0;
char my_samples[SAMPLE_BUFFER_SIZE]; char my_samples[SAMPLE_BUFFER_SIZE];
// setup stuff... // Open PCM in non-blocking
snd_pcm_open(&handle, "default:CARD=MyAwesomeAudioCard", SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
// setup rest of stuff...
// Prepare codec for output // Prepare codec for output
snd_pcm_drop(handle); // Just to be sure... snd_pcm_drop(handle); // Just to be sure...
snd_pcm_prepare(handle); snd_pcm_prepare(handle);
// ALSA gods demand their buffers to be prefilled with 2 period sizes! // ALSA gods demand their buffers to be prefilled with 2 period sizes!
snd_pcm_non_block(handle, 0); snd_pcm_non_block(handle, 0); // We want to block for the prefill
snd_pcm_writei(handle, my_samples, AUDIO_NR_OF_SAMPLES); snd_pcm_writei(handle, my_samples, AUDIO_NR_OF_SAMPLES);
snd_pcm_writei(handle, my_samples, AUDIO_NR_OF_SAMPLES); snd_pcm_writei(handle, my_samples, AUDIO_NR_OF_SAMPLES);
snd_pcm_non_block(handle, 1); snd_pcm_non_block(handle, 1); // get back to non-blocking
// Codec is started after this // Codec is started after this
snd_pcm_state(handle) == SND_PCM_STATE_RUNNING; snd_pcm_state(handle) == SND_PCM_STATE_RUNNING;
@ -542,16 +545,7 @@ int main(int argc, char **argv)
sleep(100); sleep(100);
continue; continue;
} }
if (error < 0) { // xrun recovery stuff
// xrun recovery
int recover = snd_pcm_recover(handle, error, 1);
if (recover < 0) {
// all hope is lost....
}
// After recovery, need to prefill codec again!
snd_pcm_writei(handle, my_samples, AUDIO_NR_OF_SAMPLES);
snd_pcm_writei(handle, my_samples, AUDIO_NR_OF_SAMPLES);
}
} }
} }
``` ```