diff options
| -rw-r--r-- | dxr3audio-alsa.c | 58 |
1 files changed, 55 insertions, 3 deletions
diff --git a/dxr3audio-alsa.c b/dxr3audio-alsa.c index 0e45afb..a33359d 100644 --- a/dxr3audio-alsa.c +++ b/dxr3audio-alsa.c @@ -39,7 +39,7 @@ void cAudioAlsa::openDevice() string device = "default:CARD=" + cardname; dsyslog("[dxr3-audio-alsa] opening device %s", device.c_str()); - int err = snd_pcm_open(&handle, device.c_str(), SND_PCM_STREAM_PLAYBACK, 0); + int err = snd_pcm_open(&handle, device.c_str(), SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK); if (err < 0) { esyslog("[dxr3-audio-alsa] Playback open error: %s", snd_strerror(err)); @@ -74,7 +74,13 @@ void cAudioAlsa::setup(const SampleContext& ctx) dsyslog("[dxr3-audio-alsa] changing num of channels to %d (old %d)", ctx.channels, curContext.channels); snd_pcm_hw_params_t* alsa_hwparams; + snd_pcm_sw_params_t* alsa_swparams; + snd_pcm_hw_params_alloca(&alsa_hwparams); + snd_pcm_sw_params_alloca(&alsa_swparams); + + // + // set hardware settings int err = snd_pcm_hw_params_any(handle, alsa_hwparams); if (err < 0) { @@ -100,8 +106,10 @@ void cAudioAlsa::setup(const SampleContext& ctx) esyslog("[dxr3-audio-alsa] Unable to set channels %d: %s", ctx.channels, snd_strerror(err)); } + unsigned int sr = ctx.samplerate; + // set samplerate - err = snd_pcm_hw_params_set_rate_near(handle, alsa_hwparams, (unsigned int *)&ctx.samplerate, NULL); + err = snd_pcm_hw_params_set_rate_near(handle, alsa_hwparams, &sr, NULL); if (err < 0) { esyslog("[dxr3-audio-alsa] Unable to set samplerate %d: %s", ctx.samplerate, snd_strerror(err)); } @@ -124,6 +132,51 @@ void cAudioAlsa::setup(const SampleContext& ctx) esyslog("[dxr3-audio-alsa] Cannot prepare audio interface for use: %s", snd_strerror(err)); } + // + // set software settings + + err = snd_pcm_sw_params_current(handle, alsa_swparams); + if (err < 0) { + esyslog("[dxr3-audio-alsa] Cannot get current sw params: %s", snd_strerror(err)); + } + + static snd_pcm_uframes_t chunk_size = 1024; + + // start playing when one period has been written + err = snd_pcm_sw_params_set_start_threshold(handle, alsa_swparams, chunk_size); + if (err < 0) { + esyslog("[dxr3-audio-alsa] Failed to set chunk_size: %s", snd_strerror(err)); + } + + snd_pcm_uframes_t boundary; +#if SND_LIB_VERSION >= 0x000901 + err = snd_pcm_sw_params_get_boundary(alsa_swparams, &boundary); + if (err < 0) { + esyslog("[dxr3-audio-alsa] Failed to get boundary: %s", snd_strerror(err)); + } +#else + boundary = 0x7fffffff; +#endif + + // disable underrun reporting + err = snd_pcm_sw_params_set_stop_threshold(handle, alsa_swparams, boundary); + if (err < 0) { + esyslog("[dxr3-audio-alsa] Failed to disable underrun reporting: %s", snd_strerror(err)); + } + +#if SND_LIB_VERSION >= 0x000901 + // play silence when there is an underrun + err = snd_pcm_sw_params_set_silence_size(handle, alsa_swparams, boundary); + if (err < 0) { + esyslog("[dxr3-audio-alsa] Failed to enable silence mode: %s", snd_strerror(err)); + } +#endif + + err = snd_pcm_sw_params(handle, alsa_swparams); + if (err < 0) { + esyslog("[dxr3-audio-alsa] Failed to set sw params: %s", snd_strerror(err)); + } + curContext.channels = ctx.channels; curContext.samplerate = ctx.samplerate; @@ -198,4 +251,3 @@ void cAudioAlsa::Xrun() esyslog("[dxr3-audio-alsa]: read/write error FATAL exiting"); exit(-1); } - |