[FFmpeg-devel] [PATCH] ac3dec: fix non-optimal dithering of zero bit mantissas

[Michael Niedermayer]

On Sat, Jan 05, 2013 at 10:26:07PM +0100, madshi wrote:
> 2013/1/5 Michael Niedermayer <michaelni at gmx.at>
> > divisions are slow, i would suggest:
> > mantissa = (((av_lfg_get(&s->dith_state)>>8)*181)>>8) - 5931008
> > (untested, thus testing is needed and welcome)
> 
> Looks good to me.

i agree but:

make fate fails (someone needs to update the tests and possibly
generate correct reference files, note we cannot change files on
rsync as this would break the tests for old versions, we can only add
files )

stddev:    4.94 PSNR: 82.45 MAXDIFF:   60 bytes:   380928/   380928
make: *** [fate-ac3-4.0-downmix-stereo] Error 1
stddev:    7.68 PSNR: 78.62 MAXDIFF:  188 bytes:   761856/   761856
make: *** [fate-ac3-4.0] Error 1
stddev:    6.09 PSNR: 80.62 MAXDIFF:   75 bytes:   804864/   804864
stddev:    6.72 PSNR: 79.77 MAXDIFF:   83 bytes:   190464/   190464
make: *** [fate-ac3-4.0-downmix-mono] Error 1
make: *** [fate-ac3-2.0] Error 1
stddev:    0.36 PSNR:105.14 MAXDIFF:    2 bytes:   172032/   172032
make: *** [fate-ac3-5.1-downmix-mono] Error 1
stddev:    0.31 PSNR:106.36 MAXDIFF:    2 bytes:  1032192/  1032192
make: *** [fate-ac3-5.1] Error 1
stddev:    0.29 PSNR:106.81 MAXDIFF:    2 bytes:   344064/   344064
make: *** [fate-ac3-5.1-downmix-stereo] Error 1
stddev:    4.38 PSNR: 83.50 MAXDIFF:  151 bytes:   866304/   866304
make: *** [fate-eac3-1] Error 1
stddev:  404.52 PSNR: 44.19 MAXDIFF: 4260 bytes:  1675800/  1676288
stddev:    7.46 PSNR: 78.87 MAXDIFF:  136 bytes:   798720/   798720
make: *** [fate-ac3-encode] Error 1
make: *** [fate-eac3-3] Error 1
stddev:    7.35 PSNR: 79.00 MAXDIFF:  205 bytes:  2998272/  2998272
make: *** [fate-eac3-2] Error 1

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Dictatorship naturally arises out of democracy, and the most aggravated
form of tyranny and slavery out of the most extreme liberty. -- Plato
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