From 0aed5e9fb895a31c43ff6ab4edfecb5be372f704 Mon Sep 17 00:00:00 2001
From: Bobby Bingham <uhmmmm@gmail.com>
Date: Mon, 13 Apr 2009 18:07:02 +0000
Subject: [PATCH] Skip loop iterations which are no-ops due to data1[-lag..-1]
 being zero.

Originally committed as revision 18498 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/flacenc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/flacenc.c b/libavcodec/flacenc.c
index 3c73277036..e8e5674bce 100644
--- a/libavcodec/flacenc.c
+++ b/libavcodec/flacenc.c
@@ -594,7 +594,7 @@ void ff_flac_compute_autocorr(const int32_t *data, int len, int lag,
 
     for(j=0; j<lag; j+=2){
         double sum0 = 1.0, sum1 = 1.0;
-        for(i=0; i<len; i++){
+        for(i=j; i<len; i++){
             sum0 += data1[i] * data1[i-j];
             sum1 += data1[i] * data1[i-j-1];
         }
@@ -604,7 +604,7 @@ void ff_flac_compute_autocorr(const int32_t *data, int len, int lag,
 
     if(j==lag){
         double sum = 1.0;
-        for(i=0; i<len; i+=2){
+        for(i=j-1; i<len; i+=2){
             sum += data1[i  ] * data1[i-j  ]
                  + data1[i+1] * data1[i-j+1];
         }