[ogg-dev] Re: [theora-dev] Re: [Advocacy] Re: [Vorbis-dev] Proposal: An extension to rules all others

Silvia Pfeiffer silviapfeiffer1 at gmail.com
Sun Apr 29 16:40:51 PDT 2007

On 4/30/07, Ralph Giles <giles at xiph.org> wrote:
> On Sun, Apr 29, 2007 at 10:01:58PM +1000, Silvia Pfeiffer wrote:
> > http://wiki.xiph.org/index.php/MIME_Types_and_File_Extensions
> Thanks for putting that together. A few opinions:
> > it is required that random multitrack files contain a skeleton
> > track to identify all containing logical bitstreams
> I think this should be a best-practices recommendation, not a
> requirement (SHOULD, not MUST) in accord with the general design
> principle of making it hard to make non-compliant streams. There is
> a lot of software out there producing Ogg Theora streams without a
> Skeleton, for example. Likewise, RFC 3533 doesn't mention skeleton
> as a requirement.

I deliberately called for "random multitrack formats" and tried to
exclude ones that have a more specific definition such as Ogg Theora.
I put it as a requirement, though I really think that random
multitrack files don't have another option. But I do agree, it should
be "should" rather than "must" - I knew that'd stirr a few souls. :-)

> In practice the behaviour is the same: in the presense of unrecognized
> stream types, if there is no skeleton a muxer must throw up its hands,
> but playback is largely unaffected. I think it's better to be explicit
> about this than to say skeleton's required and leave it to the
> implementation to decide how hard it should try with streams which
> violate this.

Agreed - so maybe the recommendation is that authoring sw should
support skeleton while decoding software that aims to support random
multitrack ogg files really really should ("must"?) support the
decoding of skeleton?


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