Simplify ALSA backend code

This commit is contained in:
Iwan Timmer
2014-05-25 12:44:03 +02:00
parent b59f74a96a
commit b9a39a5d89

View File

@@ -1,6 +1,3 @@
/* Use the newer ALSA API */
#define ALSA_PCM_NEW_HW_PARAMS_API
/* All of the ALSA library API is defined
* in this header */
#include <alsa/asoundlib.h>
@@ -9,42 +6,20 @@ snd_pcm_t *handle;
int nv_alsa_init(unsigned int channelCount, unsigned int sampleRate, unsigned char* device) {
int rc;
snd_pcm_hw_params_t *params;
int dir;
/* Open PCM device for playback. */
if ((rc = snd_pcm_open(&handle, device, SND_PCM_STREAM_PLAYBACK, 0)) != 0)
return rc;
snd_pcm_hw_params_alloca(&params);
snd_pcm_hw_params_any(handle, params);
if ((rc = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED)) != 0)
return rc;
if ((rc = snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE)) != 0)
return rc;
if ((rc = snd_pcm_hw_params_set_channels(handle, params, channelCount)) != 0)
return rc;
if ((rc = snd_pcm_hw_params_set_rate_near(handle, params, &sampleRate, &dir)) != 0)
return rc;
snd_pcm_uframes_t frames = 32;
if ((rc = snd_pcm_hw_params_set_period_size_near(handle, params, &frames, &dir)) != 0)
return rc;
if ((rc = snd_pcm_hw_params(handle, params)) != 0)
if ((rc = snd_pcm_set_params(handle, SND_PCM_FORMAT_S16_LE, SND_PCM_ACCESS_RW_INTERLEAVED, channelCount, sampleRate, 1, 50000)) != 0) //50ms latency
return rc;
}
int nv_alsa_play(const unsigned char* indata, int data_len) {
int frames = data_len/4; /* 2 bytes/sample, 2 channels */
int rc = snd_pcm_writei(handle, indata, frames);
if (rc == -EPIPE) {
if (rc == -EPIPE)
snd_pcm_prepare(handle);
}
return rc;
}