[Matroska-devel] CodecPrivate for MPEG-1 and MPEG-2 video

Mike Matsnev mike at po.cs.msu.su
Tue Nov 16 16:13:28 CET 2004


Steve Lhomme wrote:
>> Personally I'm voting for not putting anything into the the
>> CodecPrivate. At least not as mandatory information. The muxing app
>> MAY put a sequence header there, e.g. if the MPEG ES doesn't start with
>> one (every MPEG decoder needs a sequence header before it can decode the
>> data).
>>
>> Spyder? Any preference, additional thoughts?
> 
> 
> Well, that's quite a change. Because so far we always assume the 
> CodecPrivate is filled for each CodecID. Having an optional CodecPrivate 
> wasn't discussed so far (?). IMO eitherr we have it, or not. But in 
> between is only hacky for no good reason. It's up to spyder to tell if 
> we need the missing data or not.
Some codecs do not use CodecPrivate, it's already optional.

I accidentally replied privately to Mosu, but windows mpeg1/2 decoders
require the sequence header in the media type's format block, and I don't
really want to write code to reconstruct the seq. header from other
header values, or read the first frame to extract it from there.

/Mike



More information about the Matroska-devel mailing list