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rv34dsp: factorize a multiplication in the noround inverse transform

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Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
This commit is contained in:
Christophe GISQUET 2012-04-17 18:44:43 +00:00 committed by Ronald S. Bultje
parent d834ab0f2a
commit 7fb8b491e5
1 changed files with 8 additions and 8 deletions
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16
libavcodec/rv34dsp.c
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@ -88,15 +88,15 @@ static void rv34_inv_transform_noround_c(DCTELEM *block){
rv34_row_transform(temp, block);
for(i = 0; i < 4; i++){
const int z0 = 13*(temp[4*0+i] + temp[4*2+i]);
const int z1 = 13*(temp[4*0+i] - temp[4*2+i]);
const int z2 = 7* temp[4*1+i] - 17*temp[4*3+i];
const int z3 = 17* temp[4*1+i] + 7*temp[4*3+i];
const int z0 = 39*(temp[4*0+i] + temp[4*2+i]);
const int z1 = 39*(temp[4*0+i] - temp[4*2+i]);
const int z2 = 21* temp[4*1+i] - 51*temp[4*3+i];
const int z3 = 51* temp[4*1+i] + 21*temp[4*3+i];
block[i*4+0] = ((z0 + z3) * 3) >> 11;
block[i*4+1] = ((z1 + z2) * 3) >> 11;
block[i*4+2] = ((z1 - z2) * 3) >> 11;
block[i*4+3] = ((z0 - z3) * 3) >> 11;
block[i*4+0] = (z0 + z3) >> 11;
block[i*4+1] = (z1 + z2) >> 11;
block[i*4+2] = (z1 - z2) >> 11;
block[i*4+3] = (z0 - z3) >> 11;
}
}