this is the code for capturing audio input from mic and sampling it
i got it from http://equalarea.com/paul/alsa-audio.html


i am getting an error in compiling this program and the error is "invalid conversion from 'int' to 'unsigned int*'

the header file can be downloaded from the following link if u dont have it

http://packages.debian.org/search?se...table&arch=any




#include <stdio.h>
#include <stdlib.h>
#include <alsa/asoundlib.h>

main (int argc, char *argv[])
{
int i;
int err;
short buf[128];
snd_pcm_t *capture_handle;
snd_pcm_hw_params_t *hw_params;

if ((err = snd_pcm_open (&capture_handle, argv[1], SND_PCM_STREAM_CAPTURE, 0)) < 0) {
fprintf (stderr, "cannot open audio device %s (%s)\n",
argv[1],
snd_strerror (err));
exit (1);
}

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 (capture_handle, hw_params)) < 0) {
fprintf (stderr, "cannot initialize hardware parameter structure (%s)\n",
snd_strerror (err));
exit (1);
}

if ((err = snd_pcm_hw_params_set_access (capture_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
fprintf (stderr, "cannot set access type (%s)\n",
snd_strerror (err));
exit (1);
}

if ((err = snd_pcm_hw_params_set_format (capture_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 (capture_handle, hw_params, 44100, 0)) < 0) {
fprintf (stderr, "cannot set sample rate (%s)\n",
snd_strerror (err));
exit (1);
}

if ((err = snd_pcm_hw_params_set_channels (capture_handle, hw_params, 2)) < 0) {
fprintf (stderr, "cannot set channel count (%s)\n",
snd_strerror (err));
exit (1);
}

if ((err = snd_pcm_hw_params (capture_handle, hw_params)) < 0) {
fprintf (stderr, "cannot set parameters (%s)\n",
snd_strerror (err));
exit (1);
}

snd_pcm_hw_params_free (hw_params);

if ((err = snd_pcm_prepare (capture_handle)) < 0) {
fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
snd_strerror (err));
exit (1);
}

for (i = 0; i < 10; ++i) {
if ((err = snd_pcm_readi (capture_handle, buf, 128)) != 128) {
fprintf (stderr, "read from audio interface failed (%s)\n",
snd_strerror (err));
exit (1);
}
}

snd_pcm_close (capture_handle);
exit (0);
}

Nothing obvious in the code posted (in relation to the header.) Can you point out the line that gets the error? If not, at least post the compiler output, please.
ta0kira

The purpose of snd_pcm_hw_params_set_rate_near is to set the rate near the rate you specify. So it needs to modify the rate you give it so that you know what rate it ended up using. Thus, you need to pass a pointer and check to see what rate was actually set.

E.g.,