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| author | Rostislav Pehlivanov <atomnuker@gmail.com> | 2017-02-24 07:03:12 +0000 |
|---|---|---|
| committer | Rostislav Pehlivanov <atomnuker@gmail.com> | 2017-02-24 07:03:12 +0000 |
| commit | 22b8ada7b5e0a1ef58b21cf8e481e0c2b28ce94e (patch) | |
| tree | a0ded7be1951110cce2ef051cec7740f1c439c0e /libavcodec | |
| parent | 0d85c7bb5a4c398863848ecdf44a0c9f1778da06 (diff) | |
| download | ffmpeg-22b8ada7b5e0a1ef58b21cf8e481e0c2b28ce94e.tar.gz | |
opus_pvq: improve PVQ search for low Ks
Since the probelm mentioned only happened when the phase was negative
(e.g. the sum had to be decreased), only discarding dimensions with a
zero pulse in that case restored the search's previously low distortion
at low Ks when the phase is never negative.
Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
Diffstat (limited to 'libavcodec')
| -rw-r--r-- | libavcodec/opus_pvq.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/libavcodec/opus_pvq.c b/libavcodec/opus_pvq.c index 5920ab0ed1..0d3536718d 100644 --- a/libavcodec/opus_pvq.c +++ b/libavcodec/opus_pvq.c @@ -413,11 +413,14 @@ static void celt_pvq_search(float *X, int *y, int K, int N) y_norm += 1.0f; for (i = 0; i < N; i++) { + /* If the sum has been overshot and the best place has 0 pulses allocated + * to it, attempting to decrease it further will actually increase the + * sum. Prevent this by disregarding any 0 positions when decrementing. */ + const int ca = 1 ^ ((y[i] == 0) & (phase < 0)); float xy_new = xy_norm + 1*phase*FFABS(X[i]); float y_new = y_norm + 2*phase*FFABS(y[i]); xy_new = xy_new * xy_new; - /* FIXME: the y[i] check makes the search slightly worse at Ks below 5 */ - if (y[i] && (max_den*xy_new) > (y_new*max_num)) { + if (ca && (max_den*xy_new) > (y_new*max_num)) { max_den = y_new; max_num = xy_new; max_idx = i; |