[vorbis] AC-3 Decoding

[David Balazic]

Jared wrote:
> 
> On Wed, 8 Aug 2001, David Balazic wrote:
> 
> > Jared (jared at celab21.students.csee.uq.edu.au) wrote :
> >
> > > Saw an article today on /. which reports that Dolby are insisting the
> > > NETBSD dudes remove the ac3dec package from their site. Someone suggested
> > > that we need an open source solution.
> >
> > ac3dec is already open ( GPL ).
> 
>         Yeah it is, but the AC3 codec itself isn't, that is patented by
> Dolby, who are asking for ac3dec to be either removed, or a license fee
> payed for.
> 
> >
> > > Could Vorbis in the Ogg framework be this solution, can we create a pretty
> > > simple 5.1 stream?
> >
> > I _believe_ ogg/vorbis can support multichannel sound.
> > It also supports real spatial (3D, AC3 is only 2D) sound.
> >
> > None of this is actually available right now , AFAIK.
> 
>         I'm not quite sure what you mean by real spatial? I was always
> under the impression that AC3 was spatial due to its 5 channel nature,
> which allows for positioning of a signal almost anywhere inside the sound
> field.

1. It is only 2D, space is 3D , remember ? :-)
2. It is "hardwired" to a particular speaker setup -> lack of flexibility and scalability
3. Has less direction precision as Ambisonic ( the "thing" that will
be used by ogg/vorbis for spatial sound ) , but I am not 100% sure about
this, some of the gurus should confirm ( or deny )

> Regards,
>         J


-- 
David Balazic
--------------
"Be excellent to each other." - Bill & Ted
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