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output/alsa: pre-allocate the silence buffer

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This commit is contained in:
Max Kellermann 2013-02-04 14:35:53 +01:00
parent e06dd129dd
commit 57e825dfe7
1 changed files with 15 additions and 14 deletions
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29
src/output/AlsaOutputPlugin.cxx
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@ -106,6 +106,13 @@ struct AlsaOutput {
*/
snd_pcm_uframes_t period_position;
/**
* This buffer gets allocated after opening the ALSA device.
* It contains silence samples, enough to fill one period (see
* #period_frames).
*/
void *silence;
AlsaOutput():mode(0), writei(snd_pcm_writei) {
}
@ -580,6 +587,11 @@ configure_hw:
ad->period_frames = alsa_period_size;
ad->period_position = 0;
ad->silence = g_malloc(snd_pcm_frames_to_bytes(ad->pcm,
alsa_period_size));
snd_pcm_format_set_silence(format, ad->silence,
alsa_period_size * channels);
return true;
error:
@ -623,6 +635,7 @@ alsa_setup_dsd(AlsaOutput *ad, struct audio_format *audio_format,
g_set_error(error_r, alsa_output_quark(), 0,
"Failed to configure DSD-over-USB on ALSA device \"%s\"",
alsa_device(ad));
g_free(ad->silence);
return false;
}
@ -688,20 +701,7 @@ alsa_open(struct audio_output *ao, struct audio_format *audio_format, GError **e
static void
alsa_write_silence(AlsaOutput *ad, snd_pcm_uframes_t nframes)
{
size_t nbytes = nframes * ad->out_frame_size;
void *buffer = g_malloc(nbytes);
snd_pcm_hw_params_t *params;
snd_pcm_format_t format;
unsigned channels;
snd_pcm_hw_params_alloca(&params);
snd_pcm_hw_params_current(ad->pcm, params);
snd_pcm_hw_params_get_format(params, &format);
snd_pcm_hw_params_get_channels(params, &channels);
snd_pcm_format_set_silence(format, buffer, nframes * channels);
ad->writei(ad->pcm, buffer, nframes);
g_free(buffer);
ad->writei(ad->pcm, ad->silence, nframes);
}
static int
@ -778,6 +778,7 @@ alsa_close(struct audio_output *ao)
AlsaOutput *ad = (AlsaOutput *)ao;
snd_pcm_close(ad->pcm);
g_free(ad->silence);
}
static size_t