[vorbis-dev] Re: [theora-dev] Re: Ogg Internet Drafts - create application/ogg-vorbis, application/ogg-tarkin, etc.

Chris Hanson cmh at bDistributed.com
Fri Jan 3 15:21:47 PST 2003

At 12:00 AM +1100 1/4/03, Silvia.Pfeiffer at csiro.au wrote:
>Therefore, it will be difficult to maintain a
>generic application that will be able to interprete any random Ogg file,
>because the Ogg container by itself does not know what kind of data it

An issue that I've brought up time and again.

QuickTime movies are made up of _tracks_ with particular types. 
(Like "audio" and "video" and "effects.")

_Tracks_ are made up of _track media_ using particular CODECs.  (Like 
"Sorensen" and "Motion JPEG" and "Animation" and "AC3.")

_Track media_ are made up of _samples_.

Because QuickTime is a complete multimedia architecture, it's 
possible to write an application that can open and manipulate tracks 
within an arbitrary movie; QuickTime knows how to get the right 
samples to the right CODECs at the right time, mix them, and give 
them to your application in the format you've asked for.  For 
instance, I can write an application that renders a particular video 
track from a movie into a buffer, without knowing a thing about the 
CODECs used by the track media in that video track.

Ogg has always appeared to me to correspond only to the _track media_ 
and _sample_ layers of a QuickTime movie.  So you still need to know 
what all the CODECs are and how to use them individually to 
manipulate what should be general data in the file.  Please, somebody 
correct me if I'm wrong.

   -- Chris

Chris Hanson, bDistributed.com, Inc.  |  Email: cmh at bDistributed.com
Custom Application Development        |  Phone: +1-847-372-3955
http://bdistributed.com/              |  Fax:   +1-847-589-3738
http://bdistributed.com/Articles/     |  Personal Email: cmh at mac.com
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