eden-emu/opus
19
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Tim just rewrote half of the bit allocator -- hope it works now

Browse source 
Making sure we never waste bits due to band skip and also making
sure we don't skip bands "in the middle".
This commit is contained in:
Jean-Marc Valin 2010-12-15 00:36:41 -05:00
parent 9651ffdbb5
commit ffe1057419
1 changed files with 65 additions and 32 deletions
Download patch file Download diff file Expand all files Collapse all files

97
libcelt/rate.c
View file

@ -151,6 +151,10 @@ static inline int interp_bits2pulses(const CELTMode *m, int start, int end,
const int C = CHANNELS(_C);
int codedBands=-1;
int alloc_floor;
int left, percoeff;
int force_skipping;
int unforced_skips;
int done;
SAVE_STACK;
alloc_floor = C<<BITRES;
@ -162,14 +166,19 @@ static inline int interp_bits2pulses(const CELTMode *m, int start, int end,
{
int mid = (lo+hi)>>1;
psum = 0;
done = 0;
for (j=start;j<end;j++)
{
int tmp = bits1[j] + (mid*bits2[j]>>ALLOC_STEPS);
/* Don't allocate more than we can actually use */
if (tmp >= thresh[j])
if (tmp >= thresh[j] && !done)
{
psum += tmp;
else if (tmp >= alloc_floor + (1<<BITRES))
psum += alloc_floor + (1<<BITRES);
} else {
done = 1;
if (tmp >= alloc_floor)
psum += alloc_floor;
}
}
if (psum > (total<<BITRES))
hi = mid;
@ -178,13 +187,15 @@ static inline int interp_bits2pulses(const CELTMode *m, int start, int end,
}
psum = 0;
/*printf ("interp bisection gave %d\n", lo);*/
done = 0;
for (j=start;j<end;j++)
{
int tmp = bits1[j] + (lo*bits2[j]>>ALLOC_STEPS);
if (tmp < thresh[j])
if (tmp < thresh[j] || done)
{
if (tmp >= alloc_floor + (1<<BITRES))
tmp = alloc_floor + (1<<BITRES);
done = 1;
if (tmp >= alloc_floor)
tmp = alloc_floor;
else
tmp = 0;
}
@ -193,47 +204,69 @@ static inline int interp_bits2pulses(const CELTMode *m, int start, int end,
bits[j] = tmp;
psum += tmp;
}
for (j=start;j<end;j++)
{
if (bits[j] < thresh[j])
break;
}
codedBands = j;
if (*skip==-1)
force_skipping = 1;
unforced_skips = *skip;
*skip = 0;
codedBands=end;
for (j=end;j-->start;)
{
*skip=0;
for (j=codedBands-1;j>=0;j--)
int band_width;
int band_bits;
int rem;
/*Figure out how many left-over bits we would be adding to this band.
This can include bits we've stolen back from higher, skipped bands.*/
left = (total<<BITRES)-psum;
percoeff = left/(m->eBands[codedBands]-m->eBands[start]);
left -= (m->eBands[codedBands]-m->eBands[start])*percoeff;
rem = IMAX(left-m->eBands[j],0);
band_width = m->eBands[codedBands]-m->eBands[j];
band_bits = bits[j] + percoeff*band_width + rem;
/*As long as, even after adding these bits, we're below the threshold for
this band, it is force-skipped.*/
force_skipping = force_skipping && band_bits < thresh[j];
if (!force_skipping)
{
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))
/*If we have enough for the fine energy, but not more than a full bit
beyond that, or no more than one bit total, then don't bother
skipping this band: there's no extra bits to redistribute.*/
if ((band_bits >= alloc_floor && band_bits <= alloc_floor + (1<<BITRES))
|| band_bits < (1<<BITRES))
break;
else
(*skip)++;
/*Never skip the first band: we'd be coding a bit to signal that we're
going to waste all of the other bits.*/
if (j==start)break;
if (unforced_skips == -1)
{
/*Choose a threshold with some hysteresis to keep bands from
fluctuating in and out.*/
if (band_bits > ((j<prev?7:9)*band_width<<LM<<BITRES)>>4)
break;
} else if(unforced_skips--<=0)
break;
(*skip)++;
/*Use a bit to skip this band.*/
psum += 1<<BITRES;
band_bits -= 1<<BITRES;
}
*skip = IMIN(*skip, codedBands-start-1);
}
for (i=0;i<*skip;i++)
{
/* We add (1<<BITRES) to account for the skip bit */
psum = psum - bits[codedBands-1] + (1<<BITRES);
if (bits[codedBands-1] >= alloc_floor + (1<<BITRES))
/*Reclaim the bits originally allocated to this band.*/
psum -= bits[j];
if (band_bits >= alloc_floor + (1<<BITRES))
{
/*If we have enough for a fine energy bit per channel, use it.*/
psum += alloc_floor;
bits[codedBands-1] = alloc_floor;
} else {
/*Otherwise this band gets nothing at all.*/
bits[codedBands-1] = 0;
}
codedBands--;
}
/* Allocate the remaining bits */
if (codedBands) {
int left, perband;
left = (total<<BITRES)-psum;
perband = left/(m->eBands[codedBands]-m->eBands[start]);
if (codedBands>start) {
for (j=start;j<codedBands;j++)
bits[j] += perband*(m->eBands[j+1]-m->eBands[j]);
left = left-(m->eBands[codedBands]-m->eBands[start])*perband;
bits[j] += percoeff*(m->eBands[j+1]-m->eBands[j]);
for (j=start;j<codedBands;j++)
{
int tmp = IMIN(left, m->eBands[j+1]-m->eBands[j]);