[vorbis-dev] Re: Vorbis as a Quicktime codec

[Segher Boessenkool]

> I don't think Apple intended that about their sample code.  Here's an
> example license from Apple sample code:

I don't think they intended this, either, but...

> Copyright:    Copyright © 1999 by Apple Computer, Inc., All Rights Reserved.
> 
> You may incorporate this Apple sample source code into your program(s)
> without restriction. This Apple sample source code has been provided "AS IS"
> and the  responsibility for its operation is yours. You are not permitted to
> redistribute this Apple sample source code as "Apple sample source code"
> after having made  changes. If you're going to re-distribute the source, we
> require that you make it clear in the source that the code was descended
> from Apple sample source code, but that you've made changes.

I don't think this is fully compatible with either a BSD-style license, or
PD?  But the intention of this license is clear, at least :-)

> 
> > For future full-spec Ogg streams, we will need to write a mediahandler, I'm
> > afraid; just like mpeg system streams have a custom mediahandler, iirc.
> > I haven't found any documentation on those, but that might be just me.
> 
> There is some documentation on media handlers and derived media handlers,
> but that's only part of the problem.  What we really want to do is
> subclass the sound media handler to help it understand that sound packets
> can be fragmented (the page framing can split a sound packet across
> multiple pages.)  Another benefit of subclassing the sound media handler

MPEG Layer III streams have "fragmented" packets as well, in some sense...
There's more than one way to solve this problem.

My importer puts multiple Ogg pages into one "audio sample"; this 1) solves
the problem with zero-duration Ogg pages (i.e., containing no packet that
ends within this page), and 2) makes for a nice speed optimization (but I
should be calling AddMediaSampleReferences64() anyway).

> to understand the ogg vorbis file layout would be removing the need to
> read through and parse the entire file when it's initially opened.  Very
> beneficial for those opening files on remote servers (like iTools).

I'm not even starting to tackle this problem yet ;-)

Segher

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