[xiph-rtp] Updated Vorbis and new Theora I-D's

[Michael Smith]

On Fri, 04 Feb 2005 10:22:50 +0100, Tor-Einar Jarnbjo
<Tor-Einar at jarnbjo.de> wrote:
> Michael Smith wrote:
> 
> >The downside is that you then have a very large gap between packets -
> >particularly in live situations, this risks starving client buffers.
> >Existing vorbis-in-ogg-over-http streaming often runs into this
> >problem.
> >
> How is that supposed to happen? In any case, the same data will be fed
> to the Vorbis decoder. If a receiver has problems with this situation,
> the RTP receiver is incorrectly implemented.

Suppose the client has a one-second buffer (to account for network
conditions, or whatever).

Then, create a situation where you can fit 60 vorbis packets into an
rtp packet, probably by having digital silence (this could be several
seconds, depending on things like sample rate). You can't send the rtp
packet until you've got the data to send - in a live situation, then,
you won't be able to send it for several seconds - by which time the
client has run out of buffer.

This is easily remedied by just ensuring you send rtp packets
sufficiently frequently - which is fine, but then you've got no reason
at all to allow large numbers of vorbis packets in a single rtp
packet. So no need for the extra complexity you were suggesting.

I might be misunderstanding something (I won't claim to have
particularly great knowledge of how RTP works), in which case I'd
appreciate an explanation... but this is the problem that exists with
http-streaming currently, and I don't see why rtp would be
fundamentally different in this respect.

Mike