8magsvn – Diff between revs 26 and 28

(root)/VLF/SW/sidd2/Ix86/sidspect/src/sidspect.c

Rev 26 – Rev 29 – Go to most recent revision – Details – Blame – Last modification – View Log

 #include <math.h>
 #include <fftw3.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 unsigned int rate = 24000;			/* stream rate */
-static unsigned int buffer_time = 130000;		/* ring buffer length in us */
+static unsigned int buffer_time = 200000;		/* ring buffer length in us */
-static unsigned int period_time = 90000;		/* period time in us */
+static unsigned int period_time = 10000;		/* period time in us */
 static int verbose = 0;					/* verbose flag */
 static int resample = 1;				/* enable alsa-lib resampling */
 static int period_event = 0;				/* produce poll event after each period */
 static snd_pcm_sframes_t buffer_size;	// size of buffer at sound card
 static snd_pcm_sframes_t period_size;	//samples per frame
 static snd_output_t *output = NULL;
 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;
 	int err, dir;
 	/* choose all parameters */
 	err = snd_pcm_hw_params_any(handle, params);
 	if (err < 0) {
-		printf("Broken configuration for playback: no configurations available: %s\n", snd_strerror(err));
+		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 playback: %s\n", snd_strerror(err));
+		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 playback: %s\n", snd_strerror(err));
+		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) {
 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];
+	short signal[300000];
 	/*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
 	} while (n < period_size);
 	fftw_execute(fft_plan_left);
 	fftw_execute(fft_plan_right);
-	for(i=0; i< (period_size/2 +1); 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_left[i] += sqrt( (outl[i][0] * outl[i][0]) + (outl[i][1] * outl[i][1]) ); //acumulate average spectrum
-	for(i=0; i< (period_size/2 +1); i++) spect_avg_right[i] += sqrt( (outr[i][0] * outr[i][0]) + (outr[i][1] * outr[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 > 100){
+	if (period > 100)
+	{
-	  for(i=0; i<(period_size/2 +1); i++) spect_avg_left[i] = spect_avg_left[i]/100;
+	  for(i=0; i < frequency_bins; i++) spect_avg_left[i] = spect_avg_left[i]/100;
-	  for(i=0; i<(period_size/2 +1); i++) spect_avg_right[i] = spect_avg_right[i]/100;
+	  for(i=0; i < frequency_bins; i++) spect_avg_right[i] = spect_avg_right[i]/100;
 	  out=fopen("/tmp/sidspect","w");
+    	  for(i=0; i < frequency_bins; i++)
+	  {
-    	  for(i=0; i< (period_size/2 +1); i++) fprintf(out,"%u %6f %6f\n",i, spect_avg_left[i], spect_avg_right[i]);
+	     fprintf(out,"%6f %6f %6f\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);
+}
 	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((period_size/2 + 1), sizeof (double));
+	spect_avg_left = calloc(frequency_bins, sizeof (double));		//allocate space for frrequency spectrum
-	spect_avg_right = calloc((period_size/2 + 1), sizeof (double));
+	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) frequency_bins * 2.0;
 	inl = fftw_malloc(sizeof(double) * period_size); // period_size);
-        outl = fftw_malloc(sizeof(fftw_complex) * (period_size/2 + 1));
+        outl = fftw_malloc(sizeof(fftw_complex) * frequency_bins);
 	inr = fftw_malloc(sizeof(double) * period_size); // period_size);
-        outr = fftw_malloc(sizeof(fftw_complex) * (period_size/2 + 1));
+        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;
 	if (err < 0) {
 			printf("Start error: %s\n", snd_strerror(err));
 			exit(EXIT_FAILURE);
+	}
-//wait until all samples aren't transmitted
+// wait for interrupt
 	printf("processing audio input.. \n");
 	while(1) usleep(1000);
 	snd_pcm_close(capture_handle);