Commit 19b9c7cc authored by Loren Merritt's avatar Loren Merritt
Browse files

was computing one more autocorrelation coefficient that was actually used

Originally committed as revision 10613 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 14bd2a9f
......@@ -608,13 +608,14 @@ static void compute_autocorr(const int32_t *data, int len, int lag,
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_t *data, int len, int lag,
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 *samples, int blocksize, int max_order,
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{
......
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