[FFmpeg-devel] FFV1 Specification

Loren Merritt lorenm at u.washington.edu
Sun Apr 8 14:37:50 CEST 2012

On Sun, 8 Apr 2012, Peter B. wrote:
> On 04/08/2012 01:58 PM, Michael Niedermayer wrote:
>> yes but dont forget ffv1 can reuse range coder contexts over frames
>> so one has to set the gop size to 1 if this kind of next frame recovery
>> is important to them
> Interesting to hear that.
> These are exactly the "small details" which I'd love to find when
> reading docs about FFv1 :)
> I thought that when using an intra-frame-only codec, all frames are
> self-contained and there'd be no GOPs. Am I getting something wrong here?

In MPEG*, the entropy coder never keeps state between frames, so pixel
prediction is the only thing that can be inter or not.
FFV1 lacks inter prediction of pixels, but can keep entropy coder state,
so it has inter frames for a different reason than MPEG does.

--Loren Merritt

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