[Matroska-devel] Re: Matroska Specs Notes

Pamel paul at msn.com
Fri Nov 28 19:21:19 CET 2003


"Lhomme Steve"  wrote...
> > 2. This line, "A Matroska file contains one or more segments. It can
> > optionally
> > be safely started with the old 160-octets type header without the EOF
> > char."
> > And it has a link to the old MCF header page.  Is there really any reason
> > to support this?
>
> The type header is not needed. But a Matroska file can have many segments...
> It can actually even have more than one EBML head. That's needed if you want
> to be able to use the "cat" UNIX function. But of course there are some
> strict conditions for this to work. It should actually be only usable when
> the 2 original files were linked. Otherwise playback is "uncertain"...
> Anyway I'm not sure any player support this "cat" feature yet.

My question was really just about the use of an MCF header at the beginning of
the next segment.  Why use an MCF header and not something EBMLish?  There isn't
even any existing code to use to create the header.  If you really want a
generic custom header to append on the front, make one specific to Matroska.

> > 3.  This line, "There is currently no encryption defined. It will be
> > defined
> > when an open DRM system will exist. It should work at Block level and/or
> > Cluster
> > level and/or Track level and/or Segment level."  Encryption was just
> > defined, so
> > shouldn't this be removed?
>
> Not removed, but changed to say that one possible type of encryption is
> supported under one particular OS...

I don't think that Jory's encryption filter yet supports this feature.  I was
just saying that the needed design has been added now so this statement isn't
accurate.  If nothing else, "DRM can be used by encrypting the stream with the
ContentEncryption elements."

BTW, noone specified in the specs that the Blocks are all encrypted individualy
or whether or not the CodecPrivate is also encrypted.

> You don't need anyone's approval to correct misspelling.

I wasn't going to fix it right then, but I also didn't want to forget.  ;)

> > First, is it
> > possible to list more than one stream that the track should be the overlay
> > for?
>
> I don't have the specs here, but I don't think so.

It isn't marked as a Multi, but what if the same sub track should be used for
more than one video track?


Pamel






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