Adding some hysteresis on the folding threshold frequency
This adds some side-information that can be used to change the
threshold freq arbitrarily.
diff --git a/libcelt/rate.c b/libcelt/rate.c
index bdf34d5..301698b 100644
--- a/libcelt/rate.c
+++ b/libcelt/rate.c
@@ -142,7 +142,7 @@
static inline int interp_bits2pulses(const CELTMode *m, int start, int end,
int *bits1, int *bits2, const int *thresh, int total, int *bits,
- int *ebits, int *fine_priority, int len, int _C, int LM)
+ int *ebits, int *fine_priority, int len, int _C, int LM, int *skip, int prev)
{
int psum;
int lo, hi;
@@ -192,6 +192,25 @@
psum += bits[j];
}
codedBands++;
+ if (*skip==-1)
+ {
+ *skip=0;
+ for (j=codedBands-1;j>=0;j--)
+ {
+ if ((bits[j] > (7*(m->eBands[j+1]-m->eBands[j])<<LM<<BITRES)>>4 && j<prev)
+ || (bits[j] > (9*(m->eBands[j+1]-m->eBands[j])<<LM<<BITRES)>>4))
+ break;
+ else
+ (*skip)++;
+ }
+ *skip = IMIN(*skip, codedBands-start-1);
+ }
+ for (i=0;i<*skip;i++)
+ {
+ psum = psum - bits[codedBands-1] + ((C+1)<<BITRES);
+ bits[codedBands-1] = C<<BITRES;
+ codedBands--;
+ }
/* Allocate the remaining bits */
if (codedBands) {
int left, perband;
@@ -267,7 +286,7 @@
}
int compute_allocation(const CELTMode *m, int start, int end, int *offsets, int alloc_trim,
- int total, int *pulses, int *ebits, int *fine_priority, int _C, int LM)
+ int total, int *pulses, int *ebits, int *fine_priority, int _C, int LM, int *skip, int prev)
{
int lo, hi, len, j;
const int C = CHANNELS(_C);
@@ -286,7 +305,7 @@
/* Below this threshold, we don't allocate any PVQ bits */
for (j=start;j<end;j++)
- thresh[j] = (4*(m->eBands[j+1]-m->eBands[j])<<LM<<BITRES)>>3;
+ thresh[j] = ((C+1)<<BITRES) + (3*(m->eBands[j+1]-m->eBands[j])<<LM<<BITRES)>>4;
/* Tilt of the allocation curve */
for (j=start;j<end;j++)
trim_offset[j] = C*(m->eBands[j+1]-m->eBands[j])*(alloc_trim-5-LM)*(m->nbEBands-j-1)
@@ -334,7 +353,7 @@
bits1[j] += offsets[j];
}
codedBands = interp_bits2pulses(m, start, end, bits1, bits2, thresh,
- total, pulses, ebits, fine_priority, len, C, LM);
+ total, pulses, ebits, fine_priority, len, C, LM, skip, prev);
RESTORE_STACK;
return codedBands;
}