Started to implement onset detection

Stretch.cpp

@@ -142,6 +142,13 @@ void FFT::applywindow(FFTWindow type){
 
 
 Stretch::Stretch(REALTYPE rap_,int bufsize_,FFTWindow w,bool bypass_,REALTYPE samplerate_,int stereo_mode_){
+	onset_detection_strength=0.0;
+
+	
+#warning test
+	onset_detection_strength=0.5;
+
+
 
 	samplerate=samplerate_;
 	rap=rap_;
@@ -214,6 +221,44 @@ void Stretch::do_next_inbuf_smps(REALTYPE *smps){
 	};
 };
 
+//static bool kuku=false;
+REALTYPE Stretch::do_detect_onset(){
+	//kuku=!kuku;
+	REALTYPE result=0.0;
+	if (onset_detection_strength>1e-3){
+		REALTYPE os=0.0,osinc=0.0;
+		REALTYPE osincold=1e-5;
+		int maxk=1+(int)(bufsize*500.0/(samplerate*0.5));
+		int k=0;
+		for (int i=0;i<bufsize;i++) {
+			osinc+=infft->freq[i]-old_freq[i];
+			osincold+=old_freq[i];
+			if (k>=maxk) {
+				k=0;
+				os+=osinc/osincold;
+				osinc=0;
+			};
+			k++;
+		};
+		os+=osinc;
+		if (os<0.0) os=0.0;
+		//if (os>1.0) os=1.0;
+
+		REALTYPE os_strength=pow(20.0,sqrt(1.0-onset_detection_strength))-1.0;
+		REALTYPE os_strength_h=os_strength*0.75;
+		if (os>os_strength_h){
+			result=(os-os_strength_h)/(os_strength-os_strength_h);
+			if (result>1.0) result=1.0;
+		};
+
+		//if (kuku) printf("%g\n",result);
+		//if (kuku) printf("(%g %g) %g  => %g\n",os_strength,os_strength_h,os,result);
+
+		if (result>1.0) result=1.0;
+	};
+	return result;
+};
+
 void Stretch::process(REALTYPE *smps,int nsmps){
 	if (bypass){
 		for (int i=0;i<bufsize;i++) out_buf[i]=smps[i];
@@ -228,6 +273,7 @@ void Stretch::process(REALTYPE *smps,int nsmps){
 		if (nsmps!=0){//new data arrived: update the frequency components
 			do_analyse_inbuf(smps);		
 			if (nsmps==bufsize*2) do_analyse_inbuf(smps+bufsize);
+			REALTYPE onset=do_detect_onset();
 		};
 
 

Stretch.h

@@ -69,6 +69,10 @@ class Stretch{
 			return bufsize;
 		};
 
+		REALTYPE get_onset_detection_strength(){
+			return onset_detection_strength;
+		};
+
 		void process(REALTYPE *smps,int nsmps);
 		//		virtual void process_output(REALTYPE *smps,int nsmps){};
 
@@ -80,6 +84,8 @@ class Stretch{
 
 		void set_rap(REALTYPE newrap);//set the current stretch value
 
+		void set_onset_detection_strength(REALTYPE detection_strength);
+
 		FFTWindow window_type;
 	protected:
 		int bufsize;
@@ -92,9 +98,10 @@ class Stretch{
 
 		void do_analyse_inbuf(REALTYPE *smps);
 		void do_next_inbuf_smps(REALTYPE *smps);
+		REALTYPE do_detect_onset();
 
 //		REALTYPE *in_pool;//de marimea in_bufsize
-		REALTYPE rap;
+		REALTYPE rap,onset_detection_strength;
 		REALTYPE *old_out_smps;
 		REALTYPE *old_freq;
 		REALTYPE *new_smps,*old_smps,*very_old_smps;

readme.txt

@@ -16,10 +16,6 @@ Requirements:
 
 This algorithm/program is suitable only for extreme stretching the audio. 
 
-There is lot room for improvements on this algorithm like:
-    - on sharp attacks to make the window smaller and larger on steady sounds. This avoid adding constant sidebands on steady sounds and smoothing too much the sharp sounds.
-    - even for small window, the sidebands produced can be lowered (how?)
-
 Tips:
 	You can change the default output device with "PA_RECOMMENDED_OUTPUT_DEVICE" environment variable (used by PortAudio).
 	eg: set PA_RECOMMENDED_OUTPUT_DEVICE=1  #where 1 represents the index of the device; you can try other values for other devices
@@ -75,6 +71,7 @@ History:
     2011????(2.)
           - Added an option to preserve the tonal part or noise part
 	  - Ignored the commandline parameters starting with "-" (usefull for macosx)
+          - Improved the algorithm
 
 Enjoy! :)
 Paul