Hi again,
seems I was following a red herring. My debugger mislead me.
The function 'snd_pcm_open()' isn't the culprit, it really dies here:
==========================
int rc = 0;
int exactRate
= snd_pcm_hw_params_set_rate_near (capture_handle, hw_params,
&uSampleRate, &rc);
if(rc != 0) {
==========================
With the following definitions, declarations:
unsigned int uSampleRate - value 16100;
snd_pcm_t *capture_handle;
snd_pcm_hw_params_t *hw_params;
//ALSA library
#define ALSA_PCM_NEW_HW_PARAMS_API
#include <alsa/asoundlib.h>
It never returns from the call to "snd_pcm_hw_params_set_rate_near" and the
cpu is maxing out.
What I'm doing wrong? I'm really clueless now.
You can see from the attached text file what I've been trying...
Any help really appreciated.
Thanks,
Meinhard
>
int KCorrView::openALSADevice(){
int rc = 0;
snd_pcm_hw_params_t *hw_params;
const char *cTemp = 0;
//snd_pcm_access_t access = ;
cTemp = sDevice.ascii();
std::cerr << sDevice << std::endl;
if ((rc = snd_pcm_open (&capture_handle, sDevice.ascii(),
SND_PCM_STREAM_CAPTURE, 0)) < 0) {
std::cerr << "cannot open audio device" << sDevice << snd_strerror (rc);
return rc;
}
/* if ((rc = snd_pcm_hw_params_malloc (&hw_params)) < 0) {
std::cerr << "cannot allocate hardware parameter structure" << snd_strerror (rc);
return rc;
} */
snd_pcm_hw_params_alloca (&hw_params);
if ((rc = snd_pcm_hw_params_any (capture_handle, hw_params)) < 0) {
std::cerr << "cannot initialize hardware parameter structure" << snd_strerror (rc);
return rc;
}
if ((rc = snd_pcm_hw_params_set_access (capture_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
// cerr << "cannot set access type" << snd_strerror (rc);
return rc;
}
if ((rc = snd_pcm_hw_params_set_format (capture_handle, hw_params, SND_PCM_FORMAT_S16_LE)) < 0) {
std::cerr << "cannot set sample format " << snd_strerror (rc);
return rc;
}
if ((rc = snd_pcm_hw_params_set_channels(capture_handle, hw_params, 2)) < 0) {
std::cerr << "Could not set to stereo" << snd_strerror(rc) << std::endl;
return rc;
}
/* int exactRate
= snd_pcm_hw_params_set_rate_near (capture_handle, hw_params, &uSampleRate, &rc);
if(rc != 0) {
std::cerr << "Sample rate " << uSampleRate << "is'nt supported by your hardware. Using "
<< exactRate << "Hz instaed. " << std::endl;
}
std::cout << "snd_pcm_hw_params_set_rate_near returned with: " << exactRate << std::endl;
*/
unsigned int rrate = uSampleRate;
if((rc = snd_pcm_hw_params_set_rate_near (capture_handle, hw_params, &rrate, 0)) < 0){
std::cerr << "Failed to set sample rate: "<< uSampleRate << snd_strerror (rc);
}
if(rrate != uSampleRate) {
std::cerr << "Sample rate " << uSampleRate << "is'nt supported by your hardware. Using "
<< rrate << "Hz instaed. " << std::endl;
}
std::cout << "snd_pcm_hw_params_set_rate_near returned with: " << rc << std::endl;
if ((rc = snd_pcm_hw_params_set_channels (capture_handle, hw_params, 2)) < 0) {
std::cerr << "cannot set channel count " << snd_strerror (rc);
return rc;
}
if ((rc = snd_pcm_hw_params (capture_handle, hw_params)) < 0) {
std::cerr << "cannot set parameters " << snd_strerror (rc);
return rc;
}
snd_pcm_hw_params_free (hw_params);
if ((rc = snd_pcm_prepare (capture_handle)) < 0) {
std::cerr << "cannot prepare audio interface for use " << snd_strerror (rc);
return rc;
}
std::cout << "successfully set up ALSA 0.9 device" << std::endl;
char buf[512];
long a;
if ((a = snd_pcm_readi (capture_handle, buf, 128)) < 0) {
std::cerr << "read from audio interface failed: " << snd_strerror (a) << std::endl;
return -1;
}
/*
for(int i=0; i <128; i++){
std::cout << buf[i];
}
std::cout << " " << std::endl;
*/
return rc;
}
