diff chromagramm/Chromagram.cpp @ 0:572c856e38ac

Starting up openFrameworks project for audio time warping. The ofxFileReader goes in addons of your OF folder, the libraries and source (chromogram, fftw and source code src+ timewarp) are probably best kept in the repository, then dragged into the project afresh. That way, as we update the repository, the code that the openFrameworks project looks for will be updated.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/chromagramm/Chromagram.cpp	Tue May 17 08:48:58 2011 +0100
@@ -0,0 +1,323 @@
+
+
+#include "Chromagram.h"
+#include <iostream>
+#include <math.h>
+using namespace std;
+
+Chromagram :: Chromagram()
+{
+	pi = 3.14159265;
+	bsize = 8192;
+		
+	// array init
+	buffer = new float[8192]; // make audio buffer
+	wbuffer = new float[8192]; // to hold windowed audio buffer
+	win = new float[8192];
+	d_frame = new float[128];
+	hop = new float[1024];
+	mag = new float[(bsize/2)+1];
+	
+	maximumChromaValue = 0;
+	
+	float base = 130.81278265;
+	
+	for (int i = 0;i < 12;i++)
+	{
+		note[i] = base*pow(2,(((float) i)/12));
+	}
+	
+	harmonics = 2;
+	octaves = 2;
+	search = 2;  // p is number of bins either side of target to search for other peaks
+		
+	out = (fftwf_complex*) fftwf_malloc(sizeof(fftwf_complex) * bsize);		// complex array to hold fft
+	p = fftwf_plan_dft_r2c_1d(bsize,wbuffer,out,FFTW_FORWARD*-1);	// plan for executing fft of wbuffer
+	
+	chromaready = 0;
+}
+
+//--------------------------------------------------------------------------------------
+// destructor
+Chromagram :: ~Chromagram()
+{
+	// destroy fft plan
+    fftwf_destroy_plan(p);
+	
+	// deallocate memory
+	win = NULL;	
+	delete [] win;	
+	buffer = NULL;	
+	delete [] buffer;										
+	wbuffer = NULL;	
+	delete [] wbuffer;											
+}
+
+//--------------------------------------------------------------------------------------
+// Initialises all framesize dependent variables. Should be called to properly initialise variables and anytime the frame size changes.
+void Chromagram :: initialise(int framesize,int hsize)
+{
+	fsize = framesize;
+	hopsize = hsize;
+	
+	d_frame = new float[fsize/4];
+	hop = new float[hopsize];
+
+
+	calcrate = (hopsize*4)/fsize;
+
+	count = 0;
+	
+	//fsize = framesize; // set frame size
+		
+	ratio = ((float) 11025) / ((float) 8192);	
+	hamming(bsize);		// define a hanning window offline	
+}
+
+//--------------------------------------------------------------------------------------
+// Processes a single frame
+void Chromagram :: processframe(float frame[])
+{
+	int i;
+	int j;
+	int c;
+
+	chromaready = 0; // default case that chroma isn't ready
+
+	// downsample frame
+	downsampleframe(frame);
+		
+	if (count < calcrate)
+	{
+        c = count*(fsize/4);
+		
+		j = 0;
+		for (i = c;i < c+(fsize/4);i++)
+		{
+			hop[i] = d_frame[j];
+			j++;
+		}
+		count = count + 1;
+	}
+	    
+    if (count == calcrate)
+	{
+		for (i=0;i < 8192-hopsize;i++)
+		{
+			buffer[i] = buffer[i+hopsize];
+		}
+		
+		j = 0;
+		for (i=8192-hopsize;i < bsize;i++)
+		{
+			buffer[i] = hop[j];
+			j++;
+		}
+		        
+		chromacalc(buffer);
+		
+        count = 0;
+    }
+	
+
+}
+
+//--------------------------------------------------------------------------------------
+// Processes a single frame
+void Chromagram :: downsampleframe(float frame[])
+{
+	float filt_frame[fsize];
+	
+	float b0,b1,b2,a1,a2;
+	float x_1,x_2,y_1,y_2;
+	
+	b0 = 0.2929;
+	b1 = 0.5858;
+	b2 = 0.2929;   
+	a1 = -0.0000;
+	a2 = 0.1716;
+
+	x_1 = 0;
+	x_2 = 0;
+	y_1 = 0;
+	y_2 = 0;
+
+	for (int i=0;i < fsize;i++)
+	{
+		filt_frame[i] = frame[i]*b0 + x_1*b1 + x_2*b2 - y_1*a1 - y_2*a2;
+    
+		x_2 = x_1;
+		x_1 = frame[i];
+		y_2 = y_1;
+		y_1 = filt_frame[i];
+	}
+	
+	for (int i=0;i < (fsize/4);i++)
+	{
+		d_frame[i] = filt_frame[i*4];
+	}
+
+}
+
+//--------------------------------------------------------------------------------------
+// main function to be called with 8192 sample frame at 11025 Hz
+void Chromagram :: chromacalc(float frame[])
+{
+	int i;
+		
+	// apply hanning window to buffer
+	for (i = 0; i < bsize;i++)
+	{
+		wbuffer[i] = frame[i] * win[i];
+	}
+	
+	getmagspectrum();
+	
+	generatechromagram();
+		
+	chromaready = 1;	
+		
+//	for (i = 0;i < 12;i++)
+//	{
+//		cout << chroma[i] << " ";
+//	}	
+//	
+//	cout << endl;
+		
+	//cout << "root: " << root << "  type: " << type << "  features: " << features << endl;
+	
+	//cout << root << " " << quality << " " << intervals << endl;
+}
+
+//--------------------------------------------------------------------------------------
+// creates a chromagram from the magnitude spectrum of the input signal
+void Chromagram :: generatechromagram()
+{
+	int i;
+	float sum;
+	float notesum = 0;
+	float noteval;
+	int index;
+	float maxval = 0;
+	int searchlength;
+	
+	for (i = 0;i < 12;i++)
+	{
+		sum = 0;
+		
+		for (int oct = 1;oct <= octaves;oct++)
+		{
+			noteval = (note[i]/ratio)*((float) oct);
+			notesum = 0;
+			
+			for (int h = 1;h <= harmonics;h++)
+			{
+				index = round(noteval*((float) h));
+				
+				searchlength = search*h;
+				
+				maxval = 0;
+				for (int n = (index-searchlength);n <= index+searchlength;n++)
+				{
+					if (mag[n] > maxval)
+					{
+						maxval = mag[n];
+					}
+				}
+				
+				notesum = notesum+(maxval*(1/((float) h)));
+			}
+			sum = sum + notesum;
+			
+			if (oct == 1)
+			{
+				chroma_low[i] = notesum;
+			}
+		}
+		
+		chroma[i] = sum;
+		rawChroma[i] = sum;
+		
+		if (sum > maximumChromaValue)
+		maximumChromaValue = sum;
+		
+	}
+	
+	
+	// normalise chromagram
+	maxval = max(chroma,12);
+	
+	for (i = 0;i < 12;i++)
+	{
+		chroma[i] = chroma[i] / maxval;
+	}
+	
+}
+
+
+//--------------------------------------------------------------------------------------
+// main function to be called with 8192 sample frame at 11025 Hz
+void Chromagram :: hamming(int N)
+{
+	int n;
+		
+	// apply hanning window to buffer
+	for (n = 0; n < N;n++)
+	{
+		win[n] = 0.54 - 0.46*cos(2*pi*(((float) n)/((float) N)));
+	}
+}
+
+//--------------------------------------------------------------------------------------
+// finds mag spectrum of input
+void Chromagram :: getmagspectrum()
+{
+	int i = 0;	
+
+	// execute fft plan, i.e. compute fft of buffer
+    fftwf_execute(p);
+
+	// compute first (N/2)+1 mag values
+	for (i = 0;i < (bsize/2)+1;i++)
+	{
+		mag[i] = sqrt(pow(out[i][0],2) + pow(out[i][1],2));
+		mag[i] = sqrt(mag[i]);
+	}
+}
+
+//--------------------------------------------------------------------------------------
+// returns max value of an array
+float Chromagram :: max(float array[],int length)
+{
+	float max = 0;
+	
+	for (int i=0;i < length;i++)
+	{
+		if (array[i] > max)
+		{
+			max = array[i];
+		}
+	}
+	
+	return max;
+}
+
+//--------------------------------------------------------------------------------------
+// returns index of minimum value of array
+int Chromagram :: minindex(float array[],int length)
+{
+	float min = 10000;
+	int minindex = 0;
+	int i;
+	
+	for (i = 0;i < length;i++)
+	{
+		if (array[i] < min)
+		{
+			min = array[i];
+			minindex = i;
+		}
+	}
+	
+	return minindex;
+}
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