[FFmpeg-cvslog] r10613 - trunk/libavcodec/flacenc.c

[lorenm]

Author: lorenm
Date: Sat Sep 29 09:43:52 2007
New Revision: 10613

Log:
was computing one more autocorrelation coefficient that was actually used


Modified:
   trunk/libavcodec/flacenc.c

Modified: trunk/libavcodec/flacenc.c
==============================================================================
--- trunk/libavcodec/flacenc.c	(original)
+++ trunk/libavcodec/flacenc.c	Sat Sep 29 09:43:52 2007
@@ -608,13 +608,14 @@ static void compute_autocorr(const int32
                              double *autoc)
 {
     int i, j;
-    double tmp[len + lag];
+    double tmp[len + lag + 1];
     double *data1= tmp + lag;
 
     apply_welch_window(data, len, data1);
 
     for(j=0; j<lag; j++)
         data1[j-lag]= 0.0;
+    data1[len] = 0.0;
 
     for(j=0; j<lag; j+=2){
         double sum0 = 1.0, sum1 = 1.0;
@@ -628,8 +629,10 @@ static void compute_autocorr(const int32
 
     if(j==lag){
         double sum = 1.0;
-        for(i=0; i<len; i++)
-            sum += data1[i] * data1[i-j];
+        for(i=0; i<len; i+=2){
+            sum += data1[i  ] * data1[i-j  ]
+                 + data1[i+1] * data1[i-j+1];
+        }
         autoc[j] = sum;
     }
 }
@@ -757,7 +760,7 @@ static int lpc_calc_coefs(const int32_t 
     assert(max_order >= MIN_LPC_ORDER && max_order <= MAX_LPC_ORDER);
 
     if(use_lpc == 1){
-        compute_autocorr(samples, blocksize, max_order+1, autoc);
+        compute_autocorr(samples, blocksize, max_order, autoc);
 
         compute_lpc_coefs(autoc, max_order, lpc, ref);
     }else{