diff options
Diffstat (limited to 'libavcodec')
-rw-r--r-- | libavcodec/lpc.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/libavcodec/lpc.c b/libavcodec/lpc.c index 5cda7797e4..3839119cc2 100644 --- a/libavcodec/lpc.c +++ b/libavcodec/lpc.c @@ -173,11 +173,13 @@ double ff_lpc_calc_ref_coefs_f(LPCContext *s, const float *samples, int len, int i; double signal = 0.0f, avg_err = 0.0f; double autoc[MAX_LPC_ORDER+1] = {0}, error[MAX_LPC_ORDER+1] = {0}; - const double c = (len - 1)/2.0f; + const double a = 0.5f, b = 1.0f - a; - /* Welch window */ - for (i = 0; i < len; i++) - s->windowed_samples[i] = 1.0f - ((samples[i]-c)/c)*((samples[i]-c)/c); + /* Apply windowing */ + for (i = 0; i < len; i++) { + double weight = a - b*cos((2*M_PI*i)/(len - 1)); + s->windowed_samples[i] = weight*samples[i]; + } s->lpc_compute_autocorr(s->windowed_samples, len, order, autoc); signal = autoc[0]; |