[vorbis] [new?] Streaming technique

[Dado Colussi]

Aleksandar Dovnikovic wrote:
> 
> "Alex Iribarren" <ogg at iribarren.com> wrote:
> 
> > if so, would it be possible to build an encoder in such a way as
> > to take one input stream and make it produce 2 different files? One
> > file encoded at 64kb, and the other file with the information dropped
> > from the stream that would have made the resulting encoded stream
> > 128kb? What I mean is a way to produce 2 64kb files which could be
> > somehow "added up" on the decoder to produce a 128kb stream. Is there
> > a name for this kind of thing, or have I just made it up?
> 
> Ogg Vorbis supports bitrate peeling - thist means that if you have,
> for example a 256kbps file, you can create a 128kbps file *without*
> re-encoding (decoding to WAV and then encoding again at
> 128kbps).
> I think that this feature doesn't exist in any other codec. :-)
> 
> There is no point in having two 64kbps streams, because using
> bitrate peeling you can quickly create one 64kbps from 128kbps.

Assume you're streaming a 128kbps stream in two different
streams suggested: one base 64kbps stream and the other
64kbps add-on stream. Someone capable of receiving only
64kbps would catch the base stream. Someone else capable
of receiving all of it, would catch the add-on stream
too, and decode them as one virtual 128kbps stream.

I can see benefits of this kind of technique in
multicasting: as a multicaster you would have to send
only 128kbps *total*, instead of 128 + 64. You would
still reach narrowband users and satisfy broadband
users without sending "massively" redundant data.


-- 
Dado Colussi

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