[xiph-rtp] Lots of proposals

[David Barrett]

Tor-Einar Jarnbjo wrote:
> Ok, let me first explain why I think inline codebook delivery with or 
> without client acknowledge is one of the worst methods we have been 
> discussing until yet:
> 
> - You can't make a decent implementation of it for multicast. ...

Totally agree.  I wouldn't recommend it for multicast.


> - Inline transmission with client acknowledge will not work in 
> unidirectional network environments. ...

Totally agree.  I wouldn't recommend it for unidirectional.


> - Even in unicast situations, the delay when starting a stream may be 
> inacceptable. ...

This is where I disagree.  (And incidentally, unicast over a 
bidirectional network is far and away the most common deployment now, 
and for the forseeable future.)

Remember, TCP and UDP run over the same network.  There's nothing that 
physically makes UDP codebook delivery slower than TCP (and the reverse 
is often true).  Rather, it's all in how you build your server.

You've proposed sending codebooks at the stream rate -- a safe, 
reasonable, but very slow solution.  There are other choices that are 
still safe but much faster, especially with acknowledgement.  Indeed, if 
you choose not to play nicely with other TCP streams, you can even go 
*faster* than TCP using UDP (and for realtime data as small as 5KB, this 
might be a fine choice).


> - I would expect most usecases for Vorbis over RTP to be web radios and 
> music "on demand" services.

Anyway, this is the real reason I'm responding.  One assumption I hold 
that's biasing all of my discussion is "whatever decisions are made for 
Vorbis-rtp will likely be applied to Theora-rtp".  Can anyone confirm or 
deny that this is the case?

Personally, I think Vorbis and Theora (even Speex -- it doesn't send 
codebooks, but it does have stream parameters that must be delivered 
reliably) are so similar in this respect that we'd be silly not to use 
the same approach for all.  Do you have an opinion on this?


> - Agree on a fixed set of codebooks for RTP.  ...

I actually agree with you here, but it's my impression that this 
widely-discussed option has been formally rejected by Xiph.

-david