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| author | Michael Niedermayer <michaelni@gmx.at> | 2015-06-22 02:46:35 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2015-06-22 03:01:24 +0200 |
| commit | 4e926fb969acbb27415c2109d7339259875b6909 (patch) | |
| tree | 3c5d53ef58d42b7161d9c2f1dd27626e6b6e565b /libavcodec/jpeg2000.c | |
| parent | b1fdf81c6eed786742c08037a9aa662ef7967ab2 (diff) | |
| download | ffmpeg-4e926fb969acbb27415c2109d7339259875b6909.tar.gz | |
avcodec/jpeg2000: Move L band scaling from the 9/7f wavelet to quantization stage
This reduces the number of operations
Its not done for 9/7i as that would overflow thanks to JPEG2000 allowing
32 decomposition levels
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavcodec/jpeg2000.c')
| -rw-r--r-- | libavcodec/jpeg2000.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/libavcodec/jpeg2000.c b/libavcodec/jpeg2000.c index b61e8fec33..b333aad568 100644 --- a/libavcodec/jpeg2000.c +++ b/libavcodec/jpeg2000.c @@ -315,15 +315,20 @@ int ff_jpeg2000_init_component(Jpeg2000Component *comp, break; } if (codsty->transform != FF_DWT53) { + int lband = 0; switch (bandno + (reslevelno > 0)) { case 1: case 2: band->f_stepsize *= F_LFTG_X * 2; + lband = 1; break; case 3: band->f_stepsize *= F_LFTG_X * F_LFTG_X * 4; break; } + if (codsty->transform == FF_DWT97) { + band->f_stepsize *= pow(F_LFTG_K, 2*(codsty->nreslevels2decode - reslevelno) + lband - 2); + } } /* FIXME: In openjepg code stespize = stepsize * 0.5. Why? * If not set output of entropic decoder is not correct. */ |