[vorbis] Vorbis over RTP

[Marshall Eubanks]

Roland Parviainen wrote:

> Marshall Eubanks wrote:
> >
> > Dear Roland;
> >
> > I am working on this off and on in the context of the free amp player.
> > We hope to begin multicast streaming of ogg/vorbis early in the new year.
> > There needs to be a RFC written for the ogg/vorbis
> > data payload format so it can become a RTP type. I was hoping to
> > get this done in time of the next IETF in San Diego, but it is too late for
> > that. I definitely want to do this in time for
> > the Spring 2001 IETF in Minneapolis in March.
> >
> > With multicast streaming, packets can be dropped at any time, so
> > it is useful to keep each packet as autonomous as possible (each
> > packet should ideally be an application data unit, or ADU, as
> > Ross Finlayson did for the MP3 format - see
> > http://www.ietf.org/internet-drafts/draft-ietf-avt-rtp-mp3-04.txt ).
>
> I know, I've implemented version 2 (i think) of that draft, but
> haven't had time to update my implementation to the latest one
> yet.
>
> > In your RTP, do you send out the comments and codebook as a separate
> > packet, or as part of a data packet ? Can these change in mid-stream ?
> > It would also be nice if each packet was kept under 576 bytes (or
> > at least 1500 bytes) in size, including the IP/UDP/RTP headers,
> > to avoid fragmentation. Do you worry about packet sizes in your
> > implementation ?
>
> I send four different types of packets: data, info, comment and
> codebook. I dont' care about the size of data packets since they are
> usually less than 500 bytes, but that's just because I'm lazy :).
> The other packets are fragmented to about 1400 bytes (1400 + headers)
> if they are larger than that. The codebook is usually 3 or 4 fragments.
>

So the codebook is sent out once per second, as 3 or 4 fragments ? If there is
10% packet, then the chances of losing the codebook at ~ 30-40% - i.e., quite good.

>
> The payload header also contains a 8 bit id that changes when client
> have to reset the decoder with a new codebook, so there is no problem
> with sending e.g. a 128 kbit/s file followed by a 160 kbit/s file,
> except
> for a small delay.
>

So once you get it, you don't need it again, so if you loose it, you
can just use the last one ?

>
> //Roland Parviainen
>
> --- >8 ----


--
                                 Regards
                                 Marshall Eubanks

T.M. Eubanks
Multicast Technologies, Inc
10301 Democracy Lane, Suite 410
Fairfax, Virginia 22030
Phone : 703-293-9624
Fax     : 703-293-9609
e-mail : tme at on-the-i.com     tme at multicasttech.com

http://www.on-the-i.com http://www.buzzwaves.com

--- >8 ----
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