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Do not calculate psd and masking curve if exponents are being reused.

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Approx. 20% faster in function bit_alloc_masking().

Originally committed as revision 26042 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2010-12-17 14:16:13 +00:00
parent 68e6b0990d
commit cf7c961b19
1 changed files with 4 additions and 5 deletions
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9
libavcodec/ac3enc.c
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@ -964,11 +964,10 @@ static void bit_alloc_masking(AC3EncodeContext *s)
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
for (ch = 0; ch < s->channels; ch++) {
if (block->exp_strategy[ch] == EXP_REUSE) {
AC3Block *block1 = &s->blocks[blk-1];
memcpy(block->psd[ch], block1->psd[ch], AC3_MAX_COEFS*sizeof(block->psd[0][0]));
memcpy(block->mask[ch], block1->mask[ch], AC3_CRITICAL_BANDS*sizeof(block->mask[0][0]));
} else {
/* We only need psd and mask for calculating bap.
Since we currently do not calculate bap when exponent
strategy is EXP_REUSE we do not need to calculate psd or mask. */
if (block->exp_strategy[ch] != EXP_REUSE) {
ff_ac3_bit_alloc_calc_psd(block->exp[ch], 0,
s->nb_coefs[ch],
block->psd[ch], block->band_psd[ch]);