linux-embedded-examples/alsa-audio/monowavplayback.c

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3.9 KiB
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2017-05-03 10:47:27 +02:00
#include <stdio.h>
#include <alsa/asoundlib.h>
static unsigned int rate = 44100;
int main(int argc, char *argv[])
{
FILE *fp;
int dir;
int err;
int size;
long loops;
unsigned int rrate, val;
char *buffer;
char devname[32] = {0};
snd_pcm_t *handle;
snd_pcm_hw_params_t *params;
snd_pcm_uframes_t frames;
if (argc < 3) {
printf("Usage: %s <wavefile_name> <module_name> <rate>\n", argv[0]);
exit(EXIT_FAILURE);
}
if (argc >= 2) {
fp = fopen(argv[1], "r");
if (!fp) {
printf("Could not open file %s\n", argv[1]);
exit(EXIT_FAILURE);
}
}
if (argc == 4) {
rate = atoi(argv[3]);
printf("Requested playback rate: %d\n", rate);
}
printf("Module Name: %s\n", argv[2]);
if (!strcmp("colibri-vf", argv[2]))
strcpy(devname, "default:CARD=Audio");
else if (!strcmp("apalis-imx6", argv[2]))
strcpy(devname, "default:CARD=imx6qapalissgtl");
else if (!strcmp("colibri-imx6", argv[2]))
strcpy(devname, "default:CARD=imx6qcolibrisgtl");
else if (!strcmp("colibri-t20", argv[2]))
strcpy(devname, "default:CARD=colibrit20wm971");
else if (!strcmp("colibri-t30", argv[2]))
strcpy(devname, "default:CARD=colibrit30sgtl5");
err = snd_pcm_open(&handle, devname, SND_PCM_STREAM_PLAYBACK, 0);
if (err < 0) {
fprintf(stderr, "unable to open pcm device: %s\n", snd_strerror(err));
exit(EXIT_FAILURE);
}
snd_pcm_hw_params_alloca(&params);
err = snd_pcm_hw_params_any(handle, params);
if (err < 0) {
printf("Broken configuration for playback: no configurations available: %s\n", snd_strerror(err));
return err;
}
err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
if (err < 0) {
printf("Resampling setup failed for playback: %s\n", snd_strerror(err));
return err;
}
err = snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE);
if (err < 0) {
printf("Sample format not available for playback: %s\n", snd_strerror(err));
return err;
}
err = snd_pcm_hw_params_set_channels(handle, params, 1);
if (err < 0) {
printf("Channels count (%i) not available for playbacks: %s\n", 1, snd_strerror(err));
return err;
}
rrate = rate;
err = snd_pcm_hw_params_set_rate_near(handle, params, &rrate, 0);
if (err < 0) {
printf("Rate %iHz not available for playback: %s\n", rrate, snd_strerror(err));
return err;
}
if (rrate != rate) {
printf("Rate doesn't match (requested %iHz, get %iHz)\n", rate, err);
return -EINVAL;
}
err = snd_pcm_hw_params(handle, params);
if (err < 0) {
fprintf(stderr, "unable to set hw parameters: %s\n",
snd_strerror(err));
exit(EXIT_FAILURE);
}
/* Use a buffer large enough to hold one period */
snd_pcm_hw_params_get_period_size(params, &frames, &dir);
//size = frames * 4; /* 2 bytes/sample, 2 channels */
size = frames * 2; /* 2 bytes/sample, 1 channel */
buffer = (char *) malloc(size);
if (!buffer) {
snd_pcm_drain(handle);
snd_pcm_close(handle);
fclose(fp);
return -ENOMEM;
}
/* We want to loop for 5 seconds */
err = snd_pcm_hw_params_get_period_time(params, &val, &dir);
if (err < 0) {
printf("Unable to get period time for playback: %s\n", snd_strerror(err));
return err;
}
/* 5 seconds in microseconds divided by period time */
loops = 5000000 / val;
while (1) {
loops--;
err = fread(buffer, 1, size, fp);
if (err == 0) {
fprintf(stderr, "end of file on input\n");
break;
} else if (err != size)
fprintf(stderr, "short read: read %d bytes\n", err);
err = snd_pcm_writei(handle, buffer, frames);
if (err == -EPIPE) {
/* EPIPE means underrun */
fprintf(stderr, "underrun occurred\n");
snd_pcm_prepare(handle);
}
else if (err < 0)
fprintf(stderr, "error from writei: %s\n", snd_strerror(err));
else if (err != (int)frames)
fprintf(stderr, "short write, write %d frames\n", err);
}
snd_pcm_drain(handle);
snd_pcm_close(handle);
free(buffer);
fclose(fp);
return 0;
}