[Matroska-devel] Re: Matroska

Steve Lhomme steve.lhomme at free.fr
Sat Dec 18 11:03:26 CET 2004


dbryant at impulse.net a écrit :
> Hi Steve,
> 
> Don't apologize for the long silence, but I was starting to wonder what you
> guys were up to...  ;-)

Just handling "real" life and priorities ;)

> I've actually been really busy myself because I got a new job up near San
> Francisco, so it's been pretty hectic with commuting and, of course,
> starting a new job.

Cool, I hope you like it.

> Unfortunately, the header for WavPack 4 is completely different than the
> previous versions. I don't know what you guys are doing exactly, but you
> might want to not bother with older WavPack files. They were not block
> oriented at all; after the header the encoded data just ran continuously to
> the end of the file. They started with the original RIFF header from the wav
> file, then there was a little wavpack header with some information needed
> for decoding, then the raw WavPack data.

OK, so we'll support only Wavpack 4.
(good I use A_WAVPACK4 as the codec ID)

> I am trying to finish up version 4.2. There is not much that should concern
> you, except that it will compile and work with 64-bit compilers. Also, I

Hopefully I'll be concerned soon ;)

> have been meaning to add a flag to the playback code so that it just
> decodes whatever blocks come in; I am afraid that some of my error
> detection stuff will get confused if you try to just decode from the middle
> of a file (although I haven't actually tried it). I'll keep you posted on
> that, and even if it is a problem it will be easy to fix.

OK. In parallel to Matroska integration I think we'll need a DirectShow 
filter to play it. I hope to motivate our people to work on it. Toff 
(Christophe Paris) already have a canvas he used for CoreVorbis, CoreAAC 
and CoreFLAC, so CoreWavpack shouldn't be too hard. The difference is 
that it should handle 3 different input packets :

- full Wavpack packets
- lossy Wavpack packets
- lossy + correction Wavpack packets

But it's really not a hard issue.
Then it could also play "original" Wavpack files too.

One of the drawback on Wavpack in Matroska is that we can only store the 
packets with the same number of channels and sampling freq. Hopefully I 
don't think there are many sources that are different than that...

> BTW, my wife keeps bugging me to take her to Paris this spring (she met her
> sister there last year and enjoyed it). Maybe we can meet and have a coffee
> one day...   :-)

Of course ! I'd be glad to meet you.

> Thanks...

cya

Steve




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