[Matroska-devel] Multi-Angle

Steve Lhomme steve.lhomme at free.fr
Thu Sep 16 19:16:32 CEST 2004

Steve Lhomme a écrit :
> Steve Lhomme a écrit :
>> As we're getting closer and closer to nice DVD ripping, we need to 
>> handle multi-angles...
>> - add support in Matroska frames/block for an angle number.
> In this case I see 3 options to store it :
> - add an element in BlockGroup that would set the "sub-stream" number, 
> mandatory that would default to 0 (or 1) for backward compatibility
> - put this info in the Block, that would mean adding a new octet in 
> there (even though we could use the 5 remaining bits, but DVDs can have 
> 255 angles)
> - use a flag in the Block that says there are many angle
> In case #2 and #3 the advantage is that we keep the same 
> timecode+duration, as on DVD. But that needs some kind of lacing that 
> might not be good for video frames.
> I prefer #1: easy and simple and more flexible. The drawback is that 
> that means we can have many BlockGroups for the same track and with 
> overlapping timecodes.
> So we can have a 4th option :
> - add a new BlockGroup type (maybe a BlockGroupType element inside 
> BlockGroup) that would allow another kind of Block element. This way we 
> can introduce the so called Block2. It will break backward compatibility 
> for files that have multi-angle. But that's not a big deal in this case...

Actually all above solutions will break playback by older players when 
multi-angle is used. They already can't handle multiple video tracks, 
and this time it's even trickier. And no solution will break files using 
what is currently used... But if we introduce a Block2 some people might 
be tempted to be using that only ;)

robUx4 on blog <http://robux4.blogspot.com/>

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