[Matroska-devel] Multi-Angle

Steve Lhomme steve.lhomme at free.fr
Thu Sep 16 17:54:04 CEST 2004

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...

Opinions ?

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

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