[FFmpeg-devel] FFV1 Specification

Peter B. pb at das-werkstatt.com
Sat Apr 7 20:36:27 CEST 2012

On 04/06/2012 11:56 PM, Michael Niedermayer wrote:
> latest draft at github and at:
> http://ffmpeg.org/~michael/ffv1-draft/ffv1.html If someone could read
> through it and point out where its unclear or incomplete, that would
> be very helpfull! I imagine i can easyly miss incompletenesses given
> that i know the codec pretty well ... Also
> spellcheck/grammer/formating tips are welcome too! [...]
I've cloned the github repo and made a few minor style changes to the text.
I'm a complete git-newbie (only SVN experience so far), but from what
I've read, I could commit my changes locally and send a "pull request"?

Here are some comments/questions:

1) Which colorspaces can be handled?
The paragraph "3.5 Colorspace" merely contains a formula, which looks
like RGB-YCbCr conversion to me. Important would be to know which
colorspaces can natively be supported without any conversion.
The "high level description" mentions splitting a frame in Y/Cr/Cb/Alpha
- what if the source was RGB?

2) There's no text for "Run length coding". Is that on purpose?

3) Is "high level description" supposed to give an overview of how FFv1
Since the current text only mostly describes the colorspace and plane

4) Median predictor:
What does "diag" mean? (diagonal?)

5) Do you have any estimations about bit-error resilience of FFv1's stream?

There's probably more feedback/questions to come from me ;)


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