[alsa-devel] Fwd: [Alsa-devel] Read the input of a soundcard with ALSA
Nyx
keres.nyx at gmail.com
Wed May 2 14:23:13 CEST 2007
OK. I only want to read on the input of soundcard. So I wrote an other
program easier than the first, I write the data in file, but it seems that
it doesn't work...
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "alsa/asoundlib.h"
#include <errno.h>
unsigned int rate = 44100;
unsigned int nb_channels = 2;
int set_hwparams(snd_pcm_t *handle, snd_pcm_hw_params_t *hw_params)
{
int err;
int dir=0;
if ((err = snd_pcm_hw_params_malloc (&hw_params)) < 0) {
fprintf (stderr, "cannot allocate hardware parameter structure
(%s)\n", snd_strerror (err));
exit (1);
}
if ((err = snd_pcm_hw_params_any (handle, hw_params)) < 0) {
fprintf (stderr, "cannot initialize hardware parameter structure
(%s)\n", snd_strerror (err));
exit (1);
}
printf("Initialisation des paramètres\n");
if ((err = snd_pcm_hw_params_set_access (handle, hw_params,
SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
fprintf (stderr, "cannot set access type (%s)\n", snd_strerror
(err));
exit (1);
}
printf("Access card configuration\n");
if ((err = snd_pcm_hw_params_set_format (handle, hw_params,
SND_PCM_FORMAT_S16_LE)) < 0) {
fprintf (stderr, "cannot set sample format (%s)\n", snd_strerror
(err));
exit (1);
}
if ((err = snd_pcm_hw_params_set_rate_near (handle, hw_params, &rate,
&dir)) < 0) {
fprintf (stderr, "cannot set sample rate (%s)\n", snd_strerror
(err));
exit (1);
}
if ((err = snd_pcm_hw_params_set_channels (handle, hw_params, nb_chann))
< 0) {
fprintf (stderr, "cannot set channel count (%s)\n", snd_strerror
(err));
exit (1);
}
if ((err = snd_pcm_hw_params (handle, hw_params)) < 0) {
fprintf (stderr, "cannot set parameters (%s)\n", snd_strerror
(err));
exit (1);
}
printf("Parameters recorded\n");
//snd_pcm_hw_params_free (hw_params);
if ((err = snd_pcm_prepare (handle)) < 0) {
fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
snd_strerror (err));
exit (1);
}
return 0;
}
int main(int argc, char *argv[]){
int err;
int j;
printf("Beginning \n");
snd_pcm_hw_params_t *hw_params_capture, *hw_params_playback;
short buf[256];
FILE *file;
fichier = fopen( "/root/Desktop/Test/Audio/Capture.001", "w");
if (fichier == NULL) printf("cannot create file : %i\n", errno);
else printf("file created\n");
/*Open soundcard as capture*/
snd_pcm_t *capture_handle;
if ((err = snd_pcm_open (&capture_handle, "hw:0,0",
SND_PCM_STREAM_CAPTURE, 0)) < 0) {
fprintf (stderr, "cannot open audio device %s (%s)\n", argv[1],
snd_strerror (err));
exit (1);
}
set_hwparams(capture_handle, hw_params_capture);
for (j = 0 ; j < 256 ; j++) {
if ((err = snd_pcm_readi (capture_handle, buf, 128)) < 0)
printf("cherche pas\n");
putc(buf[j], file); //write in file LEFT Channel
putc(buf[j+1], file); //write in file RIGHT Channel
putc(0x0A, file);
}
printf("Close File\n");
fclose(file);
snd_pcm_close (capture_handle);
return 0 ;
}
What do you think about this program... ? I searched about an How-to or some
help for capture on a soundcard with ALSA, but I didn't found
Thank you
--
K
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