[Matroska-devel] MPEG in MKV

Ronald S. Bultje rbultje at ronald.bitfreak.net
Wed Jan 28 18:02:42 CET 2004

On Wed, 2004-01-28 at 17:29, John Cannon wrote:
> - GOP headers may optionally be excluded as according to the specs.

Which specs?

Any Linux MPEG decoder that I know of *requires* MPEG headers (at least
the sequence header, but I think the GOP header too) to operate
correctly. I don't know how this works for DirectShow, but I'm guessing
something similar. My experiences/experiments with alternative  video
elementary streams layouts in WMP (win2k/XP) haven't been too good.
Basically, you have to "fix" the stream everywhere where you "break" it.
If so, what's the use of allowing it to be removed? It only complicates
the demuxer and muxer.

Apart from that, seems similar to MPGI in AVI - so it's fine, I guess.
The fact that MPEG-4 is stored in display and MPEG-1 in coding order is
logical (specs), but confusing. I'd make this an explicit note in your
Matroska specs.


PS: why do stream headers go into codecpivate? Where do you use them?

Ronald Bultje <rbultje at ronald.bitfreak.net>
Linux Video/Multimedia developer

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