[ogg-dev] OggPCM version / header finalization

Silvia.Pfeiffer at csiro.au Silvia.Pfeiffer at csiro.au
Thu Nov 10 14:42:32 PST 2005

>>1) What are we trying to achieve with the "source-ID"?
>Basically I was trying to provide a method where a logical bitstream 
>could contain only a subset of the total number of channels of the 

>I know that splitting a source up across multiple logical streams is 
>ugly, but I can't think of any clean way to provide multiple sampling 
>parameters within a single stream. In most cases, all channels will have 
>the same sample parameters, so they will all be in a single logical 
>stream. I really think that requiring fixed sample parameters per 
>logical stream is a smart constraint to make.

I think there is a larger issue at hand here, which we haven't dealt with about ogg yet: when me multiplex several logical bitstreams into the one container, those logical bitstreams may be related in one way or another. For example, one audio track (I use "track" as short for "logical bitstream" here) could be the German translation of another English audio track. Or, as you are proposing, one audio track could contain 2 channels to complete another audio track to form multi-channel tracks with different encoding parameters.

I don't think putting a single parameter inside this format will solve this problem. It should be solved on a more generic level and Skeleton may be just the right place to put it. We started discussing a generic solution using Skeleton some time ago, but it never got spec-ed out properly.


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