From 57e825dfe729c80081371d22207b8eb43c49b051 Mon Sep 17 00:00:00 2001 From: Max Kellermann Date: Mon, 4 Feb 2013 14:35:53 +0100 Subject: [PATCH] output/alsa: pre-allocate the silence buffer --- src/output/AlsaOutputPlugin.cxx | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/src/output/AlsaOutputPlugin.cxx b/src/output/AlsaOutputPlugin.cxx index c50b97c13..75089f9d6 100644 --- a/src/output/AlsaOutputPlugin.cxx +++ b/src/output/AlsaOutputPlugin.cxx @@ -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(¶ms); - 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