From 593e1cbe3470f409c19a7f06f5d10c6f5677361a Mon Sep 17 00:00:00 2001
From: Ludovic Pouzenc <ludovic@pouzenc.fr>
Date: Sat, 16 Jun 2012 21:16:46 +0000
Subject: Bon, calcul du niveau sonore dans la plage 200 à 2000Hz en reprennant
 les choses calmement. Il n'est pas impossible que les valeurs soient bonnes
 :P
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git-svn-id: file:///var/svn/2012-violon-leds/trunk@19 6be1fa4d-33ac-4c33-becc-79fcb3794bb6
---
 tests/test6/compute.c | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 tests/test6/compute.c

(limited to 'tests/test6/compute.c')

diff --git a/tests/test6/compute.c b/tests/test6/compute.c
new file mode 100644
index 0000000..017416b
--- /dev/null
+++ b/tests/test6/compute.c
@@ -0,0 +1,138 @@
+#include "compute.h"
+
+#include "fft.h"
+#include <math.h>
+
+#define MIN_SAMPLES 256
+#define MAX_SAMPLES 2048
+
+//#define MAX(a,b) (a>b?a:b)
+//#define MIN(a,b) (a<b?a:b)
+
+//static inline float todB_a(const float *x);
+void compute_spectrum(float *data, int width, float output[PSHalf]);
+
+
+float compute_level(const float *data, size_t nsamples, int rate) {
+
+	size_t i; 
+	float input[MAX_SAMPLES], pwrspec[PSHalf];
+	float value;
+	int f, min_f_index, max_f_index;
+
+	if (nsamples >= MAX_SAMPLES) {
+		printf("WARN : nsamples >= MAX_SAMPLES : %i >= %i\n", nsamples, MAX_SAMPLES);
+		nsamples=MAX_SAMPLES;
+	}
+	if (nsamples < MIN_SAMPLES) {
+		printf("WARN : nsamples < MIN_SAMPLES : %i >= %i\n", nsamples, MIN_SAMPLES);
+		// Replicate with symmetry the sound to obtain an input buffer of the minimal len
+		for (i=0;i<MIN_SAMPLES;i++) {
+			if ( (i/nsamples)%2==1 )
+				input[i]=data[i]; // First channel only
+			else
+				input[i]=data[nsamples-i-1];
+		}
+		nsamples=MIN_SAMPLES;
+	} else {
+		for (i=0;i<nsamples;i++) {
+			input[i]=data[i]; // First channel only
+		}
+	}
+
+	compute_spectrum(input, nsamples, pwrspec);
+
+	// Compute the mean power for 200Hz to 2000Hz band
+	min_f_index=((float)PSHalf)*200.f/(((float)rate)/2.f);
+	max_f_index=((float)PSHalf)*2000.f/(((float)rate)/2.f);
+
+	value=0.f;
+	for (f=min_f_index;f<=max_f_index;f++) {
+		value+=pwrspec[f];
+	}
+	// Mean value
+	value=value/(max_f_index-min_f_index+1);
+
+	return value;
+}
+/*
+static inline float todB_a(const float *x){
+  return (float)((*(int32_t *)x)&0x7fffffff) * 7.17711438e-7f -764.6161886f;
+}
+*/
+// Adapted from Audacity 
+void compute_spectrum(float *data, int width, float output[PSHalf]) {
+
+	int i, start, windows;
+	float temp;
+	float in[PSNumS];
+	float out[PSHalf];
+	float processed[PSHalf]={0.0f};
+
+	start = 0;
+	windows = 0;
+	while (start + PSNumS <= width) {
+		// Windowing : Hanning
+		for (i=0; i<PSNumS; i++)
+			in[i] = data[start+i] *(0.50-0.50*cos(2*M_PI*i/(PSNumS-1)));
+
+		// Returns only the real part of the result
+		PowerSpectrum(in, out);
+
+		for (i=0; i<PSHalf; i++)
+			processed[i] += out[i];
+
+		start += PSHalf;
+		windows++;
+	}
+	// Convert to decibels
+	// But do it safely; -Inf is nobody's friend
+	for (i = 0; i < PSHalf; i++){
+		temp=(processed[i] / PSNumS / windows);
+		if (temp > 0.0)
+			output[i] = 10*log10(temp);
+		else
+			output[i] = 0;
+	}
+}
+
+void audio2hsv_1(int audio_level, int *light_h, int *light_s, int *light_v) {
+	// Dummy code
+	*light_h=-audio_level;
+	*light_s=audio_level;
+	*light_v=65535;
+}
+
+		
+void hsv2rgb(int h, int s, int v, int *r, int *g, int *b) {
+   /*
+    * Purpose:
+    * Convert HSV values to RGB values
+    * All values are in the range [0..65535]
+    */
+   float F, M, N, K;
+   int   I;
+   
+   if ( s == 0 ) {
+      /* 
+       * Achromatic case, set level of grey 
+       */
+      *r = v;
+      *g = v;
+      *b = v;
+   } else {
+      I = (int) h/(65535/6);	/* should be in the range 0..5 */
+      F = h - I;		/* fractional part */
+
+      M = v * (1 - s);
+      N = v * (1 - s * F);
+      K = v * (1 - s * (1 - F));
+
+      if (I == 0) { *r = v; *g = K; *b = M; }
+      if (I == 1) { *r = N; *g = v; *b = M; }
+      if (I == 2) { *r = M; *g = v; *b = K; }
+      if (I == 3) { *r = M; *g = N; *b = v; }
+      if (I == 4) { *r = K; *g = M; *b = v; }
+      if (I == 5) { *r = v; *g = M; *b = N; }
+   }
+}
-- 
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