[theora-dev] too mach distortion on color gradient

Alexey Fisher bug-track at fisher-privat.net
Fri Oct 8 07:02:23 PDT 2010

Am Freitag, den 08.10.2010, 14:02 +0200 schrieb Alexey Fisher:
> Hallo Monty,
> Am Donnerstag, den 07.10.2010, 17:04 -0400 schrieb xiphmont at xiph.org:
> > First off, Ptalar does handle these cases better than Thusnelda did.
> > Second, the whole problem stems from the lowest AC coeffs not getting
> > enough bits, and I'd expect that to be a result of coarse quantizers.
> > What were the exact command lines used to encode?  I'm only used to
> > seeing this effect in fairly low bitrate encodes.
> i'm not in sintel team, so i can't answer this question. 
> I send an email Ton Roosendaal (ton blender.org), will see if we will
> get some response.

Here is response from Ton,

> Hi Alexey,
> We've posted the commandlines on our blog a couple of weeks ago:
> http://www.sintel.org/news/3622/#more-3622
> With all help and expertise offered it was the best we could do... a  
> new quality ogv would be highly appreciated, that's why we uploaded  
> the pngs to xiph. :)
> We also have dpx (16 bits color) files. But some have to be re- 
> rendered still. Busy here still!

here is part of script was used:

mplayer mf://../input/png/*.png -mf w=2048:h=872:fps=24:type=png -sws 9
-vf expand=2048:1080,crop=1920:1080 -vo png:z=3
cd ..
ffmpeg2theora --keyint 24 --framerate 24 -v 8 tmp/%08d.png --title
"$title" --artist "$author" --copyright "$copyright" --license
"$license" -o output/ogg/tmp-1080.ogv
oggz-merge output/ogg/tmp-1080.ogv output/ogg/tmp-audio-51.ogg
output/ogg/tmp-subs_en.ogg output/ogg/tmp-subs_de.ogg
output/ogg/tmp-subs_es.ogg output/ogg/tmp-subs_fr.ogg
output/ogg/tmp-subs_nl.ogg output/ogg/tmp-subs_pl.ogg -o

rm tmp/*.png
rm output/ogg/tmp*.*
echo "Ogg versions encoded"


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