Skip loop iterations which are no-ops due to data1[-lag..-1] being zero.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@18498 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

diff --git a/libavcodec/flacenc.c b/libavcodec/flacenc.c
index 3c73277036d1f7d7908eaf6bc2776319326b8973..e8e5674bcec4fe29e9e4f1dcb94486fec514f2ab 100644 (file)
--- 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];
         }