[xiph-commits] r13581 - trunk/ghost/libghost

[jm at svn.xiph.org]

Author: jm
Date: 2007-08-21 08:39:05 -0700 (Tue, 21 Aug 2007)
New Revision: 13581

Modified:
   trunk/ghost/libghost/ceft.c
Log:
block-based normalisation


Modified: trunk/ghost/libghost/ceft.c
===================================================================
--- trunk/ghost/libghost/ceft.c	2007-08-20 12:45:47 UTC (rev 13580)
+++ trunk/ghost/libghost/ceft.c	2007-08-21 15:39:05 UTC (rev 13581)
@@ -51,6 +51,80 @@
 64 .. 83   (20)
 84 .. 127  (42)
 */
+
+#define NBANDS 23 /*or 22 if we discard the small last band*/
+int qbank[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 20, 24, 28, 36, 44, 52, 68, 84, 116, 128};
+
+#if 0
+void compute_bank(float *ps, float *bank)
+{
+   int i;
+   for (i=0;i<NBANDS;i++)
+   {
+      int j;
+      bank[i]=0;
+      for (j=qbank[i];j<qbank[i+1];j++)
+         bank[i] += ps[j];
+      bank[i] = sqrt(bank[i]/(qbank[i+1]-qbank[i]));
+   }
+}
+#else
+void compute_bank(float *X, float *bank)
+{
+   int i;
+   bank[0] = 1e-10+fabs(X[0]);
+   for (i=1;i<NBANDS;i++)
+   {
+      int j;
+      bank[i] = 1e-10;
+      for (j=qbank[i];j<qbank[i+1];j++)
+      {
+         bank[i] += X[j*2-1]*X[j*2-1];
+         bank[i] += X[j*2]*X[j*2];
+      }
+      bank[i] = sqrt(.5*bank[i]/(qbank[i+1]-qbank[i]));
+   }
+   //FIXME: Kludge
+   X[255] = 1;
+}
+#endif
+
+void normalise_bank(float *X, float *bank)
+{
+   int i;
+   X[0] /= bank[0];
+   for (i=1;i<NBANDS;i++)
+   {
+      int j;
+      float x = 1.f/bank[i];
+      for (j=qbank[i];j<qbank[i+1];j++)
+      {
+         X[j*2-1] *= x;
+         X[j*2]   *= x;
+      }
+   }
+   //FIXME: Kludge
+   X[255] = 0;
+}
+
+void denormalise_bank(float *X, float *bank)
+{
+   int i;
+   X[0] *= bank[0];
+   for (i=1;i<NBANDS;i++)
+   {
+      int j;
+      float x = bank[i];
+      for (j=qbank[i];j<qbank[i+1];j++)
+      {
+         X[j*2-1] *= x;
+         X[j*2]   *= x;
+      }
+   }
+   //FIXME: Kludge
+   X[255] = 0;
+}
+
 #define BARK_BANDS 20
 
 struct CEFTState_ {
@@ -81,8 +155,14 @@
    for (i=1;i<st->length>>1;i++)
       Xps[i] = .1+X[2*i-1]*X[2*i-1] + X[2*i]*X[2*i];
 
+#if 1
+   float bank[NBANDS];
+   compute_bank(X, bank);
+   normalise_bank(X, bank);
+#else
    filterbank_compute_bank(st->bank, Xps, bark);
    filterbank_compute_psd(st->bank, bark, Xps);
+   
    for(i=0;i<st->length>>1;i++)
       Xps[i] = sqrt(Xps[i]);
    X[0] /= Xps[0];
@@ -92,6 +172,7 @@
       X[2*i] /= Xps[i];
    }
    X[st->length-1] /= Xps[(st->length>>1)-1];
+#endif
    
    /*for(i=0;i<st->length;i++)
       printf ("%f ", X[i]);
@@ -101,20 +182,23 @@
    for(i=0;i<st->length;i++)
    {
       float q = 4;
-      if (i<16)
+      if (i<10)
          q = 8;
-      else if (i<32)
+      else if (i<20)
          q = 4;
-      else if (i<48)
+      else if (i<30)
          q = 2;
+      else if (i<50)
+         q = 1;
       else
-         q = 1;
-      q=1;
+         q = .5;
+      //q=1;
       int sq = floor(.5+q*X[i]);
-      //printf ("%d ", sq);
-      X[i] = (1.f/q)*sq;
+      printf ("%d ", sq);
+      X[i] = (1.f/q)*(sq);
    }
-   //printf ("\n");
+   printf ("\n");
+#if 0
    X[0]  *= Xps[0];
    for (i=1;i<st->length>>1;i++)
    {
@@ -122,6 +206,15 @@
       X[2*i] *= Xps[i];
    }
    X[st->length-1] *= Xps[(st->length>>1)-1];
+#else
+   float bank2[NBANDS];
+   compute_bank(X, bank2);
+   normalise_bank(X, bank2);
+
+   denormalise_bank(X, bank);
+#endif
+   
+   
 #if 0
    for(i=0;i<BARK_BANDS;i++)
    {