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Reduce rounding in the mode allocator and remove a scaling loop.

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This breaks the bitstream.
This commit is contained in:
Gregory Maxwell 2009-05-04 14:55:40 -04:00 • committed by Jean-Marc Valin
parent 74f4e9f385
commit ec836da27c
1 changed files with 10 additions and 17 deletions
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27
libcelt/modes.c
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@ -206,7 +206,7 @@ static void compute_pbands(CELTMode *mode, int res)
static void compute_allocation_table(CELTMode *mode, int res)
{
int i, j, eband, nBark;
int i, j, nBark;
celt_int16_t *allocVectors, *allocEnergy;
const int C = CHANNELS(mode);
@ -221,38 +221,31 @@ static void compute_allocation_table(CELTMode *mode, int res)
/* Compute per-codec-band allocation from per-critical-band matrix */
for (i=0;i<BITALLOC_SIZE;i++)
{
eband = 0;
celt_int32_t current = 0;
int eband = 0;
for (j=0;j<nBark;j++)
{
int edge, low;
celt_int32_t alloc;
edge = mode->eBands[eband+1]*res;
alloc = band_allocation[i*BARK_BANDS+j];
alloc = alloc*C*mode->mdctSize/4;
alloc = alloc*C*mode->mdctSize;
if (edge < bark_freq[j+1])
{
int num, den;
num = alloc * (edge-bark_freq[j]);
den = bark_freq[j+1]-bark_freq[j];
low = (num+den/2)/den;
allocVectors[i*mode->nbEBands+eband] += low;
allocVectors[i*mode->nbEBands+eband] = (current+low+128)/256;
current=0;
eband++;
allocVectors[i*mode->nbEBands+eband] += alloc-low;
current += alloc-low;
} else {
allocVectors[i*mode->nbEBands+eband] += alloc;
}
current += alloc;
}
}
allocVectors[i*mode->nbEBands+eband] = (current+128)/256;
}
for (i=0;i<mode->nbAllocVectors;i++)
{
for (j=0;j<mode->nbEBands;j++)
allocVectors[i*mode->nbEBands+j] = (allocVectors[i*mode->nbEBands+j]+32)/64;
}
/*for (i=0;i<mode->nbAllocVectors;i++)
{
for (j=0;j<mode->nbEBands;j++)
allocVectors[i*mode->nbEBands+j] += C;
}*/
mode->allocVectors = allocVectors;
}