[Matroska-devel] Re: Re: Re: [Ffmpeg-devel] Adding matroska supporttoFFMPEG via libmatroska/libebml, in C++ ?

Pamel paul at msn.com
Tue Oct 14 19:41:19 CEST 2003


"Alexander Noé" <alexander.noe at s2001.tu-chemnitz.de> wrote...
> Moritz Bunkus wrote:
> >Backwards compat is a MUST. Use the bit for it.

What if we just had a new ID for the new block design?  Old readers would just
skip it and would register no Blocks from the stream, which is the point of EBML
anyway.  Everything else would be identical, so new coding would just be to
handle the new ID.  What is the cost/benefit of going to a new ID?

> >How exactly should the new block look? I propose...
> >a) a flag 'same length for every block',
> >b) store all lengths EBML style and use differential to first value
> >
> I could live with that, even though it were signed variable size ints.

Would this help out with the higher bitrate codecs?  The only one that I know of
that wouldn't use the 'same length flag' would be VBR MP3.  So, would VBR MP3
benefit from using differentials?

For low bitrate I believe the main issue is Vorbis.  (Does AAC really ever use
variable sized packets?)  I remember Mosu once posted the typical sizes of
Vorbis packets.  If Vorbis uses packets that are the same size, close to each
other, than I can see this being useful, but if it typically varies the size a
lot from packet to packet, then it would probably take as much, or more, to use
the signed ints.


Pamel






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