[vorbis-dev] Quicktime components and FLAC

Ralph Giles giles at xiph.org
Fri Nov 28 07:55:23 PST 2003



On Fri, Nov 28, 2003 at 03:51:10PM +0100, Paul Wagland wrote:

> OK, so I just bought myself a nice shiny new powerbook. Nice machine.
> Very nice machine :-)

They certainly are. :)

> If I set about writing the quicktime component to play FLAC (and
> OGG/SPEEX) is anyone here interested in merging it into the mainstream?

Well, I can't speak for the qtcomponents prjoject developers, but YES, PLEASE DO! Quicktime 
support has been a huge weakness for us and we definitely welcome any help you can offer.

> Does anyone here know anything that I should be particularly wary of
> when I start to approach this project?

I've not looked at the issues my self, but I can repeat some vicious rumours. Quicktime has had 
problems with vbr audio support in the past. This may be fixed now, but for a long time the mp3 
support was a complete special-purpose hack. There also seems to be a problem with the way vorbis 
passes codec setup information at the start of the stream. I believe the current implementation 
uses a hack to get around this. A general ogg demuxer that works with multiplexed streams is 
an open question as far as I've heard. Apple has traditionally not offered us any help, even when 
someone donated a support issue on the topic.

iTunes, against all policy if not al reason, doesn't use quicktime except for play fallback. Then 
encoder plugins use some unocumented api. Someone would need to reverse-engineer that for full 
xiph-codec support.

Perhaps someone who actually knows something can follow up with real information :)

Anyway, do keep us appraised of your investigations. We're very interested in this. And good luck.

 -r
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