diff options
| -rw-r--r-- | src/audio_out/audio_alsa_out.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/src/audio_out/audio_alsa_out.c b/src/audio_out/audio_alsa_out.c index e9a0ebaa1..b516b5dbd 100644 --- a/src/audio_out/audio_alsa_out.c +++ b/src/audio_out/audio_alsa_out.c @@ -26,7 +26,7 @@ * (c) 2001 James Courtier-Dutton <James@superbug.demon.co.uk> * * - * $Id: audio_alsa_out.c,v 1.62 2002/07/01 11:33:18 pmhahn Exp $ + * $Id: audio_alsa_out.c,v 1.63 2002/07/01 11:35:46 pmhahn Exp $ */ #ifdef HAVE_CONFIG_H @@ -270,27 +270,32 @@ static int ao_alsa_open(ao_driver_t *this_gen, uint32_t bits, uint32_t rate, int printf ("audio_alsa_out: access type not available\n"); goto __close; } + /* set the sample format ([SU]{8,16{LE,BE}})*/ err = snd_pcm_hw_params_set_format(this->audio_fd, params, bits == 16 ? SND_PCM_FORMAT_S16_LE : SND_PCM_FORMAT_U8); if (err < 0) { printf ("audio_alsa_out: sample format non available\n"); goto __close; } + /* set the count of channels */ err = snd_pcm_hw_params_set_channels(this->audio_fd, params, this->num_channels); if (err < 0) { printf ("audio_alsa_out: channels count non available\n"); goto __close; } + /* set the stream rate [Hz] */ err = snd_pcm_hw_params_set_rate_near(this->audio_fd, params, rate, 0); if (err < 0) { printf ("audio_alsa_out: rate not available\n"); goto __close; } + /* ERROR: Set buffer size [samples] */ buffer_size = snd_pcm_hw_params_set_buffer_size_near(this->audio_fd, params, 500000); if (buffer_size < 0) { printf ("audio_alsa_out: buffer time not available\n"); goto __close; } + /* ERROR: Set period size [samples] */ period_size = 128; do { period_size *= 2; @@ -307,8 +312,10 @@ static int ao_alsa_open(ao_driver_t *this_gen, uint32_t bits, uint32_t rate, int printf ("audio_alsa_out: buffer time and period time match, could not use\n"); goto __close; } + /* Check for pause/resume support */ this->has_pause_resume = ( snd_pcm_hw_params_can_pause (params) && snd_pcm_hw_params_can_resume (params) ); + /* write the parameters to device */ err = snd_pcm_hw_params(this->audio_fd, params); if (err < 0) { printf ("audio_alsa_out: pcm hw_params failed: %s\n", snd_strerror(err)); @@ -319,27 +326,32 @@ static int ao_alsa_open(ao_driver_t *this_gen, uint32_t bits, uint32_t rate, int /* * audio buffer size handling */ + /* Copy current parameters into swparams */ err = snd_pcm_sw_params_current(this->audio_fd, swparams); if (err < 0) { printf ("audio_alsa_out: Unable to determine current swparams: %s\n", snd_strerror(err)); goto __close; } + /* align all transfers to 1 sample */ err = snd_pcm_sw_params_set_xfer_align(this->audio_fd, swparams, 1); if (err < 0) { printf ("audio_alsa_out: Unable to set transfer alignment: %s\n", snd_strerror(err)); goto __close; } + /* allow the transfer when at least period_size samples can be processed */ err = snd_pcm_sw_params_set_avail_min(this->audio_fd, swparams, period_size); if (err < 0) { printf ("audio_alsa_out: Unable to set available min: %s\n", snd_strerror(err)); goto __close; } + /* start the transfer when the buffer contains at least period_size samples */ err = snd_pcm_sw_params_set_start_threshold(this->audio_fd, swparams, period_size); if (err < 0) { printf ("audio_alsa_out: Unable to set start threshold: %s\n", snd_strerror(err)); goto __close; } + /* Install swparams into current parameters */ err = snd_pcm_sw_params(this->audio_fd, swparams); if (err < 0) { printf ("audio_alsa_out: Unable to set swparams: %s\n", snd_strerror(err)); |