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jpeg2000dec: optimize dequantization_float() 

4700 -> 2700 cycles (sandybridge  i7)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2013-05-31 15:36:49 +02:00
parent c485c835fe
commit 6cbd0241f2
1 changed files with 8 additions and 7 deletions
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15
libavcodec/jpeg2000dec.c
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@ -923,13 +923,14 @@ static void dequantization_float(int x, int y, Jpeg2000Cblk *cblk,
Jpeg2000Component *comp,
Jpeg2000T1Context *t1, Jpeg2000Band *band)
{
int i, j, idx;
float *datap = &comp->f_data[(comp->coord[0][1] - comp->coord[0][0]) * y + x];
for (j = 0; j < (cblk->coord[1][1] - cblk->coord[1][0]); ++j)
for (i = 0; i < (cblk->coord[0][1] - cblk->coord[0][0]); ++i) {
idx = (comp->coord[0][1] - comp->coord[0][0]) * j + i;
datap[idx] = (float)(t1->data[j][i]) * band->f_stepsize;
}
int i, j;
int w = cblk->coord[0][1] - cblk->coord[0][0];
for (j = 0; j < (cblk->coord[1][1] - cblk->coord[1][0]); ++j) {
float *datap = &comp->f_data[(comp->coord[0][1] - comp->coord[0][0]) * (y + j) + x];
int *src = t1->data[j];
for (i = 0; i < w; ++i)
datap[i] = src[i] * band->f_stepsize;
}
}
/* Integer dequantization of a codeblock.*/