On Tuesday 23 July 2002 10:19 am, Kevin Fisher wrote:

> Interesting...I'm attempting to get an RTP/RTSP-based mp3
> jukebox/server up and running.  Does Spread use RTP/RTSP over
> multicast, or something else?

Spread was designed as a general messaging system with a simple API, 
not as a multimedia system.

It has its own protocol that uses multicast and point-to-point 
communications between daemons as needed (depending on network 
topology).

It (at least the open-source version; I haven't looked at the 
commercial version) has no QOS or realtime hooks. So you get messages 
when you get them.

However, you can have (using the Causal service type) multiple streams 
ordered with respect to each other.

Whether this will work for you with multimedia depends a lot on your 
network. It probably won't work well for video over the Internet.

I'd recommend sticking with RTP/RTSP for multimedia.

> Have you seen VideoLAN at all?  (www.videolan.org)
> I don't know if it uses Spread, but it seems to do some of what you
> describe.  One of these days I'd like to get it working...I only
> had a small amount of success with it the last time I tried, but I
> didn't really spend enough time playing with it.

Thanks for the pointer.

My needs are really not for multimedia, but for distributed object 
communications and distributed I/O (telemetry/control). Luckily, we 
don't have any particular real-time requirements (this is good 
because our LAN speed can vary from 2400 bps to 10Mbps, and packets 
can take from 1 to 10 or so hops to get where they're going, 
depending on the current topology of the mobile mesh.

I might make a group-based Nebraska system (Spebraska?) in which 
anyone could see anyone else's Hands in their world, without having 
to expressly set up links between Squeak images.

This could be useful (I think) in an educational system; one user 
could be watched by all the others, or you could have one-on-one 
communications, etc., all flexibly reconfigured.

-- 
Ned Konz
http://bike-nomad.com
GPG key ID: BEEA7EFE