///////////////////////////////////////////////////////////////////////////////////
//
//
///////////////////////////////////////////////////////////////////////////////////
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sched.h>
#include <errno.h>
#include <getopt.h>
#include <alsa/asoundlib.h>
#include <sys/time.h>
#include <math.h>
#include <fftw3.h>
#include <signal.h>
static char *device = "plughw:0,0"; /* playback device */
static snd_pcm_format_t format = SND_PCM_FORMAT_S16; /* sample format */
static unsigned int rate = 98000; /* stream rate */
static int resample = 1; /* enable alsa-lib resampling */
static int period_event = 0; /* produce poll event after each period */
static snd_pcm_uframes_t buffer_size = 20004; //samples per frame
static snd_pcm_uframes_t period_size = 4000;
static snd_output_t *output = NULL;
snd_pcm_t *playback_handle, *capture_handle;
FILE *out;
double df; //frequency resolution
unsigned int frequency_bins; // number of output frequency bins
double *inl, *inr;
fftw_complex *outl, *outr;
fftw_plan fft_plan_left, fft_plan_right;
double *spect_avg_left, *spect_avg_right;
unsigned int period;
#define PERIODS 100 // number of periods to average
void leave(int sig);
static int set_hwparams(snd_pcm_t *handle, snd_pcm_hw_params_t *params, unsigned int channels)
{
unsigned int rrate;
int err, dir;
/* choose all parameters */
err = snd_pcm_hw_params_any(handle, params);
if (err < 0) {
printf("Broken configuration for capture: no configurations available: %s\n", snd_strerror(err));
return err;
}
/* set hardware resampling */
err = snd_pcm_hw_params_set_rate_resample(handle, params, resample);
if (err < 0) {
printf("Resampling setup failed for capture: %s\n", snd_strerror(err));
return err;
}
/* set the interleaved read/write format */
err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
if (err < 0) {
printf("Access type not available for capture: %s\n", snd_strerror(err));
return err;
}
/* set the sample format */
err = snd_pcm_hw_params_set_format(handle, params, format);
if (err < 0) {
printf("Sample format not available for capture: %s\n", snd_strerror(err));
return err;
}
/* set the count of channels */
err = snd_pcm_hw_params_set_channels(handle, params, channels);
if (err < 0) {
printf("Channels count (%i) not available for capture: %s\n", channels, snd_strerror(err));
return err;
}
/* set the stream rate */
rrate = rate;
err = snd_pcm_hw_params_set_rate_near(handle, params, &rrate, 0);
if (err < 0) {
printf("Rate %iHz not available for capture: %s\n", rate, snd_strerror(err));
return err;
}
if (rrate != rate) {
printf("Rate doesn't match (requested %iHz, get %iHz)\n", rate, err);
return -EINVAL;
}
else printf("Sampling rate set to %i Hz\n", rate, err);
/* set the buffer size */
err = snd_pcm_hw_params_set_buffer_size_near(handle, params, &buffer_size);
if (err < 0) {
printf("Unable to set maximal buffer size for capture: %s\n", snd_strerror(err));
return err;
}
else printf("Size of capture buffer set to %i\n", (int) buffer_size);
snd_pcm_hw_params_set_period_size_near(handle, params, &period_size, &dir);
if (err < 0) {
printf("Unable to set maximal period size %i for capture: %s\n", (int) period_size, snd_strerror(err));
return err;
}
else printf("Size of capture period (FFT width) set to %i\n", (int) period_size);
/* write the parameters to device */
err = snd_pcm_hw_params(handle, params);
if (err < 0) {
printf("Unable to set hw params for capture: %s\n", snd_strerror(err));
return err;
}
return 0;
}
static int set_swparams(snd_pcm_t *handle, snd_pcm_sw_params_t *swparams)
{
int err;
/* get the current swparams */
err = snd_pcm_sw_params_current(handle, swparams);
if (err < 0) {
printf("Unable to determine current swparams for playback: %s\n", snd_strerror(err));
return err;
}
/* start the transfer when the buffer is almost full: */
/* (buffer_size / avail_min) * avail_min */
err = snd_pcm_sw_params_set_start_threshold(handle, swparams, (buffer_size / period_size) * period_size);
if (err < 0) {
printf("Unable to set start threshold mode for playback: %s\n", snd_strerror(err));
return err;
}
/* allow the transfer when at least period_size samples can be processed */
/* or disable this mechanism when period event is enabled (aka interrupt like style processing) */
err = snd_pcm_sw_params_set_avail_min(handle, swparams, period_event ? buffer_size : period_size);
if (err < 0) {
printf("Unable to set avail min for playback: %s\n", snd_strerror(err));
return err;
}
/* enable period events when requested */
if (period_event) {
err = snd_pcm_sw_params_set_period_event(handle, swparams, 1);
if (err < 0) {
printf("Unable to set period event: %s\n", snd_strerror(err));
return err;
}
}
/* write the parameters to the playback device */
err = snd_pcm_sw_params(handle, swparams);
if (err < 0) {
printf("Unable to set sw params for playback: %s\n", snd_strerror(err));
return err;
}
return 0;
}
struct async_private_data {
signed short *samples;
snd_pcm_channel_area_t *areas;
unsigned int period;
};
/////////// CALL BACK STUFF ///////////////////
static void async_capture_callback(snd_async_handler_t *ahandler)
{
snd_pcm_t *handle = snd_async_handler_get_pcm(ahandler);
int err;
unsigned int i, n;
short signal[100000];
/*signal = calloc( (unsigned int) period_size, sizeof(short) );
if (signal = NULL) printf("memory allocation failed");*/
while (snd_pcm_avail_update(handle) >= period_size) { // read until data is ready in buffer
err = snd_pcm_readi(handle, signal, period_size);
if (err < 0) {
printf("Read error: %s\n", snd_strerror(err));
exit(EXIT_FAILURE);
}
if (err != period_size) {
printf("Read error: red %i expected %li\n", err, period_size);
exit(EXIT_FAILURE);
}
n=0;
i=0;
do {
inl[n]= signal[i]/32768.0;
inr[n]= signal[i+1]/32768.0;
n++;
i+=2;
} while (n < period_size);
fftw_execute(fft_plan_left);
fftw_execute(fft_plan_right);
for(i=0; i < frequency_bins; i++) spect_avg_left[i] += sqrt( (outl[i][0] * outl[i][0]) + (outl[i][1] * outl[i][1]) ); //acumulate average spectrum
for(i=0; i < frequency_bins; i++) spect_avg_right[i] += sqrt( (outr[i][0] * outr[i][0]) + (outr[i][1] * outr[i][1]) ); //acumulate average spectrum
period++;
}
if (period > PERIODS)
{
for(i=0; i < frequency_bins; i++) spect_avg_left[i] = spect_avg_left[i]/PERIODS; // finally average spectrum data
for(i=0; i < frequency_bins; i++) spect_avg_right[i] = spect_avg_right[i]/PERIODS;
out=fopen("/tmp/sidspec","w");
for(i=0; i < frequency_bins; i++) //write spectrum to file
{
fprintf(out,"%.5e %.5e %.5e\n",(i+0.5)*df, spect_avg_left[i], spect_avg_right[i]);
spect_avg_left[i]=0;
spect_avg_right[i]=0;
}
fclose(out);
period=0;
}
// free(signal);
}
int main(int argc, char *argv[])
{
int err;
snd_pcm_hw_params_t *hwparams;
snd_pcm_sw_params_t *swparams;
signed short *frame; // pointer to array of samples
unsigned int chn;
snd_pcm_channel_area_t *areas;
struct async_private_data data;
snd_async_handler_t *chandler;
snd_pcm_hw_params_alloca(&hwparams);
snd_pcm_sw_params_alloca(&swparams);
printf("SID monitor 2.0 starting work.. \n");
(void) signal(SIGINT,leave);
//open and set capture device
if ((err = snd_pcm_open(&capture_handle, device, SND_PCM_STREAM_CAPTURE, 0)) < 0) {
printf("Playback open error: %s\n", snd_strerror(err));
return 0;
}
else printf("Using audio device: %s\n", device);
if ((err = set_hwparams(capture_handle, hwparams, 2)) < 0) {
printf("Setting of hwparams failed: %s\n", snd_strerror(err));
exit(EXIT_FAILURE);
}
if ((err = set_swparams(capture_handle, swparams)) < 0) {
printf("Setting of swparams failed: %s\n", snd_strerror(err));
exit(EXIT_FAILURE);
}
frequency_bins = period_size/2 + 1;
spect_avg_left = calloc(frequency_bins, sizeof (double)); //allocate space for frrequency spectrum
spect_avg_right = calloc(frequency_bins, sizeof (double));
// register capture callback
err = snd_async_add_pcm_handler(&chandler, capture_handle, async_capture_callback, &data); // fill by dummy &data
if (err < 0) {
printf("Unable to register async handler\n");
exit(EXIT_FAILURE);
}
// setup fft
df = (double) rate/ (double) period_size;
inl = fftw_malloc(sizeof(double) * period_size); // period_size);
outl = fftw_malloc(sizeof(fftw_complex) * frequency_bins);
inr = fftw_malloc(sizeof(double) * period_size); // period_size);
outr = fftw_malloc(sizeof(fftw_complex) * frequency_bins);
fft_plan_left = fftw_plan_dft_r2c_1d(period_size, inl, outl, FFTW_ESTIMATE);
fft_plan_right = fftw_plan_dft_r2c_1d(period_size, inr, outr, FFTW_ESTIMATE);
period=0;
//start capture
if ((err = snd_pcm_prepare (capture_handle)) < 0) {
fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
snd_strerror (err));
exit (1);
}
err = snd_pcm_start(capture_handle);
if (err < 0) {
printf("Start error: %s\n", snd_strerror(err));
exit(EXIT_FAILURE);
}
// wait for interrupt
printf("processing audio input.. \n");
while(1) usleep(1000);
snd_pcm_close(capture_handle);
return 0;
}
void leave(int sig)
{
printf("\nTerminating.. \n");
snd_pcm_close(capture_handle);
// fclose(out);
free(spect_avg_left);
free(spect_avg_right);
free(inl);
free(inr);
free(outl);
free(outr);
exit(sig);
}
