[Ffmpeg-devel] lossless video codec comparison

Michael Niedermayer michaelni
Mon Mar 19 15:51:29 CET 2007


On Mon, Mar 19, 2007 at 08:32:14AM -0600, Loren Merritt wrote:
> On Mon, 19 Mar 2007, Kostya wrote:
> >On Mon, Mar 19, 2007 at 01:11:26AM -0600, Loren Merritt wrote:
> >>
> >>imho the most interesting part is the arithcoder. Unlike
> >>ffv1/snow/h264/vp*/jpeg2k which use binary arithcoders, lagarith stores a
> >>whole coefficient in one symbol. End result is apparently that it's only
> >>a few % slower than vlc.
> >
> >Isn't that a normal operating mode for traditional arithmetic coding
> >(and range coding too)?
> Yes, but I haven't seen it successfully used in a real codec before. 
> Probably because there's no fast way to make it adapt to the observed
> probabilities, you have to explicitely record a probability table.

it would be interresting to compare non adaptive/static propability
AC and non binary AC against the current code for snow/ffv1

also the initial probability states for both snow&ffv1 could be improved ...

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 
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