[Matroska-devel] problems with AVC in Matroska

Moritz Bunkus moritz at bunkus.org
Sat Jan 15 11:14:20 CET 2005


Hey,

the mistake I made last night was that in my example B frames references
their "neighbors" while they should reference their surrounding I/P
frames only. So here's an update.

> Now let's get back to the first block of frames. In that case I've
> assumed that the "traditional" B frame model applies to AVC as well. The
> timecodes and references for that example are:

Corrected example:

> I frame, timecode 0, no ref
> P frame, timecode 167, ref -167
> B frame, timecode 42, ref -42 and +125
> B frame, timecode 83, ref -83 and +84
> B frame, timecode 125, ref -125 and +42
> P frame, timecode 292, ref -125
> B frame, timecode 209, ref -42 and +83
> B frame, timecode 250, ref -83 and +42
> I frame, timecode 334, no ref
> I frame, timecode 375, no ref
> P frame, timecode 417, ref -42
> P frame, timecode 501, ref -84
> B frame, timecode 459, ref -42 and +42
> P frame, timecode 584, ref -83
> 
> This list can be easily converted to I/P frames only with _sane_
> references by simply forgetting about all forward references and
> re-labeling the "former" B frames as P frames:

Corrected example:

> I frame, timecode 0, no ref
> P frame, timecode 167, ref -167
> B frame, timecode 42, ref -42
> B frame, timecode 83, ref -83
> B frame, timecode 125, ref -125
> P frame, timecode 292, ref -125
> B frame, timecode 209, ref -42
> B frame, timecode 250, ref -83
> I frame, timecode 334, no ref
> I frame, timecode 375, no ref
> P frame, timecode 417, ref -42
> P frame, timecode 501, ref -84
> B frame, timecode 459, ref -42
> P frame, timecode 584, ref -83
> 
> IMHO this is the only good way to timestamp frames and calculate the
> references needed for the P frames for our method #2.

Comments?

Mosu

-- 
If Darl McBride was in charge, he'd probably make marriage
unconstitutional too, since clearly it de-emphasizes the commercial
nature of normal human interaction, and probably is a major impediment
to the commercial growth of prostitution. - Linus Torvalds



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