[Ffmpeg-devel] lossless video codec comparison
Mon Mar 19 13:38:59 CET 2007
On Mon, Mar 19, 2007 at 01:11:26AM -0600, Loren Merritt wrote:
> On Sun, 18 Mar 2007, Mike Melanson wrote:
> >The more interesting part about Lagarith is that it was designed for
> >parallelization and the only version available is pre-optimized for MMX.
> >This makes it difficult to RE a description for the Wiki:
> The MMX parts are all identical to functions found in other codecs, so
> that's no problem.
> I also don't see anything about the format that's especially "designed for
> parallelization". Any intra-only format is embarrassingly parallel: just
> run multiple codec instances on different frames.
> 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)?
> --Loren Merritt
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