""

svn path=/trunk/; revision=325

1 files changed, 202 insertions, 0 deletions

diff --git a/externals/grill/fftease/src/makewindows.c b/externals/grill/fftease/src/makewindows.c
new file mode 100644
index 00000000..1287390e
--- /dev/null
+++ b/externals/grill/fftease/src/makewindows.c
@@ -0,0 +1,202 @@
+#include "pv.h"
+#include "math.h"
+
+/*
+ * make balanced pair of analysis (A) and synthesis (S) windows;
+ * window lengths are Nw, FFT length is N, synthesis interpolation
+ * factor is I, and osc is true (1) if oscillator bank resynthesis 
+ * is specified
+ */
+void makewindows( float *H, float *A, float *S, int Nw, int N, int I, int osc )
+{
+ int i ;
+ float sum ;
+float PI, TWOPI;
+
+PI = 3.141592653589793115997963468544185161590576171875;
+TWOPI = 6.28318530717958623199592693708837032318115234375;
+
+/*
+ * basic Hamming windows
+ */
+    for ( i = 0 ; i < Nw ; i++ )
+	H[i] = A[i] = S[i] = 0.54 - 0.46*cos( TWOPI*i/(Nw - 1) ) ;
+/*
+ * when Nw > N, also apply interpolating (sinc) windows to
+ * ensure that window are 0 at increments of N (the FFT length)
+ * away from the center of the analysis window and of I away
+ * from the center of the synthesis window
+ */
+    if ( Nw > N ) {
+     float x ;
+
+/*
+ * take care to create symmetrical windows
+ */
+	x = -(Nw - 1)/2. ;
+	for ( i = 0 ; i < Nw ; i++, x += 1. )
+	    if ( x != 0. ) {
+		A[i] *= N*sin( PI*x/N )/(PI*x) ;
+		if ( I )
+		    S[i] *= I*sin( PI*x/I )/(PI*x) ;
+	    }
+    }
+/*
+ * normalize windows for unity gain across unmodified
+ * analysis-synthesis procedure
+ */
+    for ( sum = i = 0 ; i < Nw ; i++ )
+	sum += A[i] ;
+
+    for ( i = 0 ; i < Nw ; i++ ) {
+     float afac = 2./sum ;
+     float sfac = Nw > N ? 1./afac : afac ;
+	A[i] *= afac ;
+	S[i] *= sfac ;
+    }
+
+    if ( Nw <= N && I ) {
+	for ( sum = i = 0 ; i < Nw ; i += I )
+	    sum += S[i]*S[i] ;
+	for ( sum = 1./sum, i = 0 ; i < Nw ; i++ )
+	    S[i] *= sum ;
+    }
+}
+
+void makehamming( float *H, float *A, float *S, int Nw, int N, int I, int osc,int  odd )
+{
+ int i;
+ float sum ;
+float PI, TWOPI;
+
+PI = 3.141592653589793115997963468544185161590576171875;
+TWOPI = 6.28318530717958623199592693708837032318115234375;
+
+/*
+ * basic Hamming windows
+ */
+ 
+ 
+ if (odd) {
+    for ( i = 0 ; i < Nw ; i++ )
+	  H[i] = A[i] = S[i] = sqrt(0.54 - 0.46*cos( TWOPI*i/(Nw - 1) ));
+ }
+	
+ else {
+
+   for ( i = 0 ; i < Nw ; i++ )
+	  H[i] = A[i] = S[i] = 0.54 - 0.46*cos( TWOPI*i/(Nw - 1) );
+
+ }
+ 	
+/*
+ * when Nw > N, also apply interpolating (sinc) windows to
+ * ensure that window are 0 at increments of N (the FFT length)
+ * away from the center of the analysis window and of I away
+ * from the center of the synthesis window
+ */
+    if ( Nw > N ) {
+     float x ;
+
+/*
+ * take care to create symmetrical windows
+ */
+	x = -(Nw - 1)/2. ;
+	for ( i = 0 ; i < Nw ; i++, x += 1. )
+	    if ( x != 0. ) {
+		A[i] *= N*sin( PI*x/N )/(PI*x) ;
+		if ( I )
+		    S[i] *= I*sin( PI*x/I )/(PI*x) ;
+	    }
+    }
+/*
+ * normalize windows for unity gain across unmodified
+ * analysis-synthesis procedure
+ */
+    for ( sum = i = 0 ; i < Nw ; i++ )
+	sum += A[i] ;
+
+    for ( i = 0 ; i < Nw ; i++ ) {
+     float afac = 2./sum ;
+     float sfac = Nw > N ? 1./afac : afac ;
+	A[i] *= afac ;
+	S[i] *= sfac ;
+    }
+
+    if ( Nw <= N && I ) {
+	for ( sum = i = 0 ; i < Nw ; i += I )
+	    sum += S[i]*S[i] ;
+	for ( sum = 1./sum, i = 0 ; i < Nw ; i++ )
+	    S[i] *= sum ;
+    }
+}
+
+
+void makehanning( float *H, float *A, float *S, int Nw, int N, int I, int osc, int odd )
+{
+ int i;
+ float sum ;
+float PI, TWOPI;
+
+PI = 3.141592653589793115997963468544185161590576171875;
+TWOPI = 6.28318530717958623199592693708837032318115234375;
+
+/*
+ * basic Hanning windows
+ */
+ 
+ 
+ if (odd) {
+    for ( i = 0 ; i < Nw ; i++ )
+	  H[i] = A[i] = S[i] = sqrt(0.5 * (1. + cos(PI + TWOPI * i / (Nw - 1))));
+ }
+	
+ else {
+
+   for ( i = 0 ; i < Nw ; i++ )
+	  H[i] = A[i] = S[i] = 0.5 * (1. + cos(PI + TWOPI * i / (Nw - 1)));
+
+ }
+ 	
+/*
+ * when Nw > N, also apply interpolating (sinc) windows to
+ * ensure that window are 0 at increments of N (the FFT length)
+ * away from the center of the analysis window and of I away
+ * from the center of the synthesis window
+ */
+    if ( Nw > N ) {
+     float x ;
+
+/*
+ * take care to create symmetrical windows
+ */
+	x = -(Nw - 1)/2. ;
+	for ( i = 0 ; i < Nw ; i++, x += 1. )
+	    if ( x != 0. ) {
+		A[i] *= N*sin( PI*x/N )/(PI*x) ;
+		if ( I )
+		    S[i] *= I*sin( PI*x/I )/(PI*x) ;
+	    }
+    }
+/*
+ * normalize windows for unity gain across unmodified
+ * analysis-synthesis procedure
+ */
+    for ( sum = i = 0 ; i < Nw ; i++ )
+	sum += A[i] ;
+
+    for ( i = 0 ; i < Nw ; i++ ) {
+     float afac = 2./sum ;
+     float sfac = Nw > N ? 1./afac : afac ;
+	A[i] *= afac ;
+	S[i] *= sfac ;
+    }
+
+    if ( Nw <= N && I ) {
+	for ( sum = i = 0 ; i < Nw ; i += I )
+	    sum += S[i]*S[i] ;
+	for ( sum = 1./sum, i = 0 ; i < Nw ; i++ )
+	    S[i] *= sum ;
+    }
+}
+