From cf7c961b1901c04464f255863f9e09b6ea1ccb13 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Fri, 17 Dec 2010 14:16:13 +0000
Subject: [PATCH] Do not calculate psd and masking curve if exponents are being
 reused. Approx. 20% faster in function bit_alloc_masking().

Originally committed as revision 26042 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/ac3enc.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
index 3e8f08a263..3495db0ad5 100644
--- a/libavcodec/ac3enc.c
+++ b/libavcodec/ac3enc.c
@@ -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]);