[Matroska-devel] Question

Steve Lhomme steve.lhomme at free.fr
Sun Dec 18 18:50:00 CET 2005


Sorry for the late reply, but I've been very busy moving to a new place 
(and working on CoreTheque) for the last months.

ivanburnin at hushmail.com wrote:
> I haven't seen these in anything yet, but I admit I haven't looked 
> all that deeply.
> I know Matroska is capable of having multiple audio channels, and 
> multiple video channels. Is there currently any way to create a 
> scripting mixing board for them (this allows overriding, and can 
> handle multiple scripts for multiple purposes), as well as 
> hopefully a 3D sound positioning mechanism (again scriptable).

For the scripting you can add a Chapter Codec of your own to do whatever 
you want. But you'll need to do the support in the player too. Only VLC 
can support the DVD chapter codec that was made as an example. It's GPL 
so if you want something closed-source you'll need to find other solutions.

> I'm thinking about something like a Karaoke situation, where 
> storing both the background only and full audio versions would 
> require nearly double the space of background only & speex 
> compressed voice. Alternately a situational performance where for 
> example in a Jazz combo at may be desirable to bring out the 
> trumpet, but not lose the original data, allowing a great deal of 
> flexibility in playback. With a suitable amplification/speaker 
> environment it would be possible to do a great many very 
> interesting things with this, and with live recordings the 
> flexibility could open many more possibilities.

This was supposed to be handled by Control Tracks, but what remains of 
control tracks are the DVD button track. The rest is done with chapters. 
The good side of it is that it can be managed in an easier way (just 
write the XML manually or with a custom made software). I don't remember 
if the part for enabling/disabling tracks for the DVD Chapter codec but 
it could be done. There is already a feature to map DVD tracks to 
Matroska track IDs.

> So my question is: Is there a positioning and mixing script 
> facility available? And assuming there isn't, is there any other 
> interest in seeing one?

Interrest is only if someone needs it. DVDs have such capatibilities and 
it's almost completely supported in Matroska. It's through a specific 
codec. Now any other codec could be created.

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