aisdecoder/src/lib/alsaaudio/alsaaudio.c

120 lines
3.5 KiB
C
Executable File

/*
* input.c
*
* (c) Ruben Undheim 2008
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <strings.h>
#include "config.h"
#include "alsaaudio.h"
#include "hmalloc.h"
#ifdef DMALLOC
#include <dmalloc.h>
#endif
int input_initialize(snd_pcm_t * handle, short **buffer, int *buffer_l, int channels_num, char *error_msg)
{
int err;
int dir;
snd_pcm_hw_params_t *hwparams = NULL;
snd_pcm_hw_params_alloca(&hwparams);
if ((err = snd_pcm_hw_params_any(handle, hwparams)) < 0) {
sprintf(error_msg, "Error initializing hwparams");
return -1;
}
if ((err = snd_pcm_hw_params_set_access(handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
sprintf(error_msg, "Error setting acecss mode (SND_PCM_ACCESS_RW_INTERLEAVED): %s", snd_strerror(err));
return -1;
}
if ((err = snd_pcm_hw_params_set_format(handle, hwparams, SND_PCM_FORMAT_S16_LE)) < 0) {
sprintf(error_msg, "Error setting format (SND_PCM_FORMAT_S16_LE): %s", snd_strerror(err));
return -1;
}
if ((err = snd_pcm_hw_params_set_channels(handle, hwparams, channels_num)) < 0) {
sprintf(error_msg, "Error setting channels %d: %s", channels_num, snd_strerror(err));
return -1;
}
unsigned int rate = 48000;
if ((err = snd_pcm_hw_params_set_rate_near(handle, hwparams, &rate, 0)) < 0) {
sprintf(error_msg, "Error setting sample rate (%d): %s", rate, snd_strerror(err));
return -1;
}
snd_pcm_uframes_t size = 4096; /* number of frames */
dir = 0;
if ((err = snd_pcm_hw_params_set_period_size_near(handle, hwparams, &size, &dir)) < 0) {
sprintf(error_msg, "Error setting buffer size (%lu): %s", size, snd_strerror(err));
return -1;
}
if ((err = snd_pcm_hw_params(handle, hwparams)) < 0) {
sprintf(error_msg, "Error writing hwparams: %s", snd_strerror(err));
return -1;
}
snd_pcm_hw_params_get_period_size(hwparams, &size, &dir);
//int extra = (int) size % 5;
//*buffer_l = (int) size - extra;
*buffer_l = (int) size;
int buffer_len_in_bytes = *buffer_l * sizeof(short) * channels_num;
// hlog(LOG_DEBUG, LOGPREFIX "Using sound buffer size: %d frames of %d channels: %d bytes",
// *buffer_l, channels, buffer_len_in_bytes);
*buffer = (short *) hmalloc(buffer_len_in_bytes);
bzero(*buffer, buffer_len_in_bytes);
return 0;
}
int alsa_read(snd_pcm_t * handle, short *buffer, int count)
{
int err;
err = snd_pcm_readi(handle, buffer, count);
if (err == -EPIPE) {
// hlog(LOG_ERR, LOGPREFIX "Overrun");
snd_pcm_prepare(handle);
} else if (err < 0) {
// hlog(LOG_ERR, LOGPREFIX "Read error");
} else if (err != count) {
// hlog(LOG_INFO, LOGPREFIX "Short read, read %d frames", err);
} else {
/*hlog(LOG_DEBUG, LOGPREFIX "Read %d samples", err); */
}
return err;
}
void input_cleanup(snd_pcm_t *handle)
{
snd_pcm_close(handle);
}