Tuning the allocation trim

libcelt/celt.c

@@ -572,11 +572,14 @@ static int alloc_trim_analysis(const CELTMode *m, const celt_norm *X,
          trim_index-=3;
       else if (sum > QCONST16(.92,10))
          trim_index-=2;
-      else if (sum > QCONST16(.75,10))
+      else if (sum > QCONST16(.8,10))
          trim_index-=1;
+      else if (sum < QCONST16(.4,10))
+         trim_index+=1;
    }
 #if 0
    float diff=0;
+   int c;
    for (c=0;c<C;c++)
    {
       for (i=0;i<nbEBands-1;i++)
@@ -590,8 +593,8 @@ static int alloc_trim_analysis(const CELTMode *m, const celt_norm *X,
       trim_index--;
    if (diff > 8)
       trim_index--;
-   /*if (diff < -10)
-      trim_index++;*/
+   if (diff < -4)
+      trim_index++;
 #endif
    if (trim_index<0)
       trim_index = 0;

libcelt/rate.c

@@ -278,8 +278,10 @@ int compute_allocation(const CELTMode *m, int start, int end, int *offsets, int
    ALLOC(thresh, len, int);
    ALLOC(trim_offset, len, int);
 
+   /* Below this threshold, we don't allocate any PVQ bits */
    for (j=start;j<end;j++)
       thresh[j] = 3*(C*(m->eBands[j+1]-m->eBands[j])<<LM<<BITRES)>>3;
+   /* Tilt of the allocation curve */
    for (j=start;j<end;j++)
       trim_offset[j] = C*(m->eBands[j+1]-m->eBands[j])*(alloc_trim-3)*(m->nbEBands-j-1)
             <<(LM+BITRES)>>5;