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improved psymodel/quantizer

--- a/libfaac/aacquant.c

+++ b/libfaac/aacquant.c

@@ -17,7 +17,7 @@

  * License along with this library; if not, write to the Free Software

  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  *

- * $Id: aacquant.c,v 1.27 2003/09/24 16:26:00 knik Exp $

+ * $Id: aacquant.c,v 1.28 2003/10/30 08:38:21 knik Exp $

  */

 #include <math.h>

@@ -370,7 +370,7 @@

                             double *xr, double *xmin, int quality)

 {

   int sfb, start, end, l;

-  const double globalthr = 37.3 / (double)quality;

+  const double globalthr = 120.0 / (double)quality;

   int last = coderInfo->lastx;

   int lastsb = 0;

   int *cb_offset = coderInfo->sfb_offset;

@@ -377,8 +377,8 @@

   int num_cb = coderInfo->nr_of_sfb;

   double avgenrg = coderInfo->avgenrg;

-    for (sfb = 0; sfb < num_cb; sfb++)

-    {

+  for (sfb = 0; sfb < num_cb; sfb++)

+  {

     if (last > cb_offset[sfb])

       lastsb = sfb;

   }

@@ -388,8 +388,8 @@

     double thr, tmp;

     double enrg = 0.0;

-        start = cb_offset[sfb];

-        end = cb_offset[sfb + 1];

+    start = cb_offset[sfb];

+    end = cb_offset[sfb + 1];

     if (sfb > lastsb)

     {

@@ -397,22 +397,45 @@

       continue;

     }

+    if (coderInfo->block_type != ONLY_SHORT_WINDOW)

+    {

+      double enmax = -1.0;

+      double lmax;

+

+      lmax = start;

+      for (l = start; l < end; l++)

+      {

+	if (enmax < (xr[l] * xr[l]))

+	{

+	  enmax = xr[l] * xr[l];

+	  lmax = l;

+	}

+      }

+

+      start = lmax - 2;

+      end = lmax + 3;

+      if (start < 0)

+	start = 0;

+      if (end > last)

+	end = last;

+    }

+

     for (l = start; l < end; l++)

+    {

       enrg += xr[l]*xr[l];

+    }

     thr = enrg/((double)(end-start)*avgenrg);

-    thr = pow(thr, 0.2*(lastsb-sfb)/lastsb + 0.2);

+    thr = pow(thr, 0.1*(lastsb-sfb)/lastsb + 0.3);

-    tmp = (double)start / (double)last;

-    if (tmp < 0.3)

-      tmp = 0.2 + 0.3333 * tmp;

+    tmp = 1.0 - ((double)start / (double)last);

+    tmp = tmp * tmp * tmp + 0.075;

-    tmp = 0.13 / tmp;

-    thr = 1.0 / (thr + tmp);

+    thr = 1.0 / (1.4*thr + tmp);

-    xmin[sfb] = ((coderInfo->block_type == ONLY_SHORT_WINDOW) ? 0.65 : 1.0)

+    xmin[sfb] = ((coderInfo->block_type == ONLY_SHORT_WINDOW) ? 0.65 : 1.12)

       * globalthr * thr;

-    }

+  }

 }

 static int FixNoise(CoderInfo *coderInfo,

@@ -425,8 +448,7 @@

 {

     int i, sb;

     int start, end;

-    double quantvol, diffvol;

-    double quantfac;

+    double diffvol;

     double tmp;

     const double ifqstep = pow(2.0, 0.1875);

     const double log_ifqstep = 1.0 / log(ifqstep);

@@ -475,24 +497,17 @@

 		   adj43);

       //printf("\tsfac: %d\n", sfac);

-      quantvol = 0.0;

-      for (i = start; i < end; i++)

-	quantvol += xr[i] * xr[i];

-

     calcdist:

-      quantfac = pow(2.0, -0.25*(coderInfo->scale_factor[sb] - coderInfo->global_gain));

-

       diffvol = 0.0;

       for (i = start; i < end; i++)

       {

-	tmp = (pow43[xi[i]] * quantfac) - fabs(xr[i]);

-	diffvol += tmp * tmp;

-    }

+	tmp = xi[i];

+	diffvol += tmp * tmp;  // ~x^(3/2)

+      }

-      tmp = quantvol - diffvol;

-      if (tmp < (1e-6 * quantvol))

-        tmp = 1e-6 * quantvol;

-      tmp = sqrt(diffvol / tmp);

+      if (diffvol < 1e-6)

+	diffvol = 1e-6;

+      tmp = pow(diffvol / (double)(end - start), -0.666);

       if (fabs(fixstep) > maxstep)

       {

@@ -571,8 +586,7 @@

 	  goto calcdist;

 	}

       }

-      //printf("%d: %g\t%g - %g(%d)\n", sb, quantvol, diffvol/quantvol, xmin[sb], coderInfo->scale_factor[sb]);

-            }

+    }

     return 0;

 }