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| author | Rostislav Pehlivanov <atomnuker@gmail.com> | 2015-09-19 16:25:58 +0100 |
|---|---|---|
| committer | Rostislav Pehlivanov <atomnuker@gmail.com> | 2015-09-19 16:25:58 +0100 |
| commit | 0cfdaf45c41ab62bef7f74c12950d755a26a301b (patch) | |
| tree | 4346ca43272afb40b964141c521c742754fe9599 | |
| parent | 9db6c8815d9dc2f18b1a996372ec71900adb3638 (diff) | |
| download | ffmpeg-0cfdaf45c41ab62bef7f74c12950d755a26a301b.tar.gz | |
lpc: correctly apply windowing to the samples in the float-only lpc
Also change the window to Hamming (using coefficient which make it
a Hanning).
Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
| -rw-r--r-- | libavcodec/lpc.c | 10 | ||||
| -rw-r--r-- | tests/fate/aac.mak | 2 |
2 files changed, 7 insertions, 5 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]; diff --git a/tests/fate/aac.mak b/tests/fate/aac.mak index 72fc59df5a..f30d4dbbc5 100644 --- a/tests/fate/aac.mak +++ b/tests/fate/aac.mak @@ -181,7 +181,7 @@ fate-aac-tns-encode: CMD = enc_dec_pcm adts wav s16le $(TARGET_SAMPLES)/audio-re fate-aac-tns-encode: CMP = stddev fate-aac-tns-encode: REF = $(SAMPLES)/audio-reference/luckynight_2ch_44kHz_s16.wav fate-aac-tns-encode: CMP_SHIFT = -4096 -fate-aac-tns-encode: CMP_TARGET = 650.28 +fate-aac-tns-encode: CMP_TARGET = 650.37 fate-aac-tns-encode: FUZZ = 2.8 fate-aac-tns-encode: SIZE_TOLERANCE = 3560 |