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#include <stdio.h>
#include <stdlib.h>
#include <tinyalsa/pcm.h>
static size_t read_frames(void **frames)
{
unsigned int card = 0;
unsigned int device = 0;
int flags = PCM_IN;
const struct pcm_config config = {
.channels = 2,
.rate = 48000,
.format = PCM_FORMAT_S32_LE,
.period_size = 1024,
.period_count = 2,
.start_threshold = 1024,
.silence_threshold = 1024 * 2,
.stop_threshold = 1024 * 2
};
struct pcm *pcm = pcm_open(card, device, flags, &config);
if (pcm == NULL) {
fprintf(stderr, "failed to allocate memory for PCM\n");
return 0;
} else if (!pcm_is_ready(pcm)){
pcm_close(pcm);
fprintf(stderr, "failed to open PCM\n");
return 0;
}
pcm_prepare(pcm);
unsigned int frame_size = pcm_frames_to_bytes(pcm, 1);
unsigned int frames_per_sec = pcm_get_rate(pcm);
*frames = malloc(frame_size * frames_per_sec);
if (*frames == NULL) {
fprintf(stderr, "failed to allocate frames\n");
pcm_close(pcm);
return 0;
}
int read_count = pcm_readi(pcm, *frames, frames_per_sec);
size_t byte_count = pcm_frames_to_bytes(pcm, read_count);
pcm_close(pcm);
return byte_count;
}
static int write_file(const void *frames, size_t size)
{
FILE *output_file = fopen("audio.raw", "wb");
if (output_file == NULL) {
perror("failed to open 'audio.raw' for writing");
return EXIT_FAILURE;
}
fwrite(frames, 1, size, output_file);
fclose(output_file);
return 0;
}
int main(void)
{
void *frames = NULL;
size_t size = 0;
size = read_frames(&frames);
if (size == 0) {
return EXIT_FAILURE;
}
if (write_file(frames, size) < 0) {
free(frames);
return EXIT_FAILURE;
}
free(frames);
return EXIT_SUCCESS;
}
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