Re: [AVT] Vorbis RTP issues list for Vienna

[Aaron Colwell <acolwell@real.com>]

I agree with Ross on this. It seems that these codebooks are causing too
many problems that aren't worth dealing with. People have been suggesting
getting the codebooks via HTTP, alternate TCP links, and all sorts of
other methods. If your going to go that far why not just use HTTP to
deliver the data. That way you are guaranteed to get everything in the
right order.

My guess is that other video and audio codecs use predefined tables to
avoid this very problem. Vorbis should do the same. The Vorbis folks
should come up with a "streamable" profile that encodes the audio using
predefined codebooks. Doing this makes all of the complicated codebook
issues go away. They could also create an offline tool that will translate
any Vorbis file into a "streamable" Vorbis file. This idea is similar to
hinting tools used for MPEG4 and 3GPP files.

Aaron

On Wed, 9 Jul 2003, Ross Finlayson wrote:

>
> >I may be incorrect here, but from my discussions with Phil earlier
> >in the year, the codebook issue has these requirements:
> >
> >  -- May change every few minutes (say, once per song when used for
> >     Internet radio apps).
>
> IMHO, this is a flaw in the "Vorbis" architecture.  It would be much better
> to have a fixed, predefined set of codebooks that all receivers would know
> in advance.  Then you'd need to send only a 'codebook id', which should be
> small enough to include in the Vorbis RTP payload format header.
>
> Having to send a complete codebook for each song partially defeats the
> purpose of audio compression.
>
> The Vorbis designers should just figure out a complete set of codebooks
> that are likely to be useful, and settle on those.
>
>          Ross.
>
>
> _______________________________________________
> Audio/Video Transport Working Group
> avt@ietf.org
> https://www1.ietf.org/mailman/listinfo/avt
>

_______________________________________________
Audio/Video Transport Working Group
avt@ietf.org
https://www1.ietf.org/mailman/listinfo/avt