[vorbis-dev] vorbis.com

Segher Boessenkool segher at wanadoo.nl
Fri Dec 29 23:38:52 PST 2000



> scaling down to a lower bitrate without reencoding.  There aren't any
> tools to do it yet.

How will it work? Michael says my guess (just chopping the packet) is
incorrect...

> > -- I've never seen anything in the source supporting surround channels.
> 
> Well, we can do 5.1 now, but I hope to make Ambisonics the official
> surround post-1.0.  This is actually somewhat orthogonal to the rest.

I'm still not able to access CVS, sorry.

> > -- I don't think Vorbis can do sample-gran seeks (yeah, sure, we can
> >    emulate it, but anyone can, and it's not implemented at this time).
> 
> Sure we can.  Vorbis streams include information (inferred from the
> Ogg page granulepos) such that samples don't necessarily have to begin
> or end on packet boundaries.  The whole packet is decoded, of course,
> but n samples at the beginning or end can be marked to be discarded.
> Thus the sample granularity seek/edit claim (well, seek is easy
> regardless, but vorbisfile does provide it :-)

If I understand correctly, the stream is just a sequence of blocks,
and it says "oh wait, chop A samples off of the start, and B samples
off of the end"? Or this _per block_?

Cheers,

Segher

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