[vorbis] Vorbis over RTP

[Marshall Eubanks]

Roland Parviainen wrote:
> 
> Hi.
> 
> I got bored of writing papers last week so I decided to write an app for
> sending and receiving multicast vorbis streams over RTP. A first version
> is available here:
> 
> http://www.cdt.luth.se/~rolle/vorbis/
> 
> (I use the JOrbis decoder, so you need Java 2 with Javasound, e.g.
> JDK1.3. Since the decoding is done in Java, you probably need at least
> 300-350 MHz. Works with the IBM JDK1.3 on Linux on a K6-2 350)
> 
> Is there anyone else that is working on RTP and vorbis? The payload
> format need to be a bit more complex than just putting Ogg packets
> inside RTP since a client can join a multicast stream at any time and
> need to get the first three packets to initialize the decoder (the info,
> comment and codebook packets). I currently resend these three packets
> continously, adding about 5 kbit/s to the bandwidth. (Can be reduced,
> but then the client have to wait longer for all packets, now it is less
> than 1 second.) The codebook and info packets can also change when a new
> file is transmitted.
> 
> //Roland Parviainen
> 
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 ).
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 ?

                                   Regards
                                   Marshall Eubanks

   Multicast Technologies, Inc.
   10301 Democracy Lane, Suite 201
   Fairfax, Virginia 22030
   Phone : 703-293-9624          Fax     : 703-293-9609     
   e-mail : tme at on-the-i.com     http://www.on-the-i.com

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.