[AG-TECH] Real Time Music Collaboration

Michael Grobe grobe at raven.cc.ku.edu
Mon Mar 11 18:59:49 CST 2002

> I don't know what the delays are through an AG system, but I
> bet they vary from site to site and are above 20 ms!  I suspect
> that collaboration will therefore require some approach
> similar to the above, where players hear a central source
> but mute the other collaborators.  I can't remember whether
> one can specify a delay in RAT - I think this will be
> needed on a site-by-site basis.  The other possibility would
> be for site 1 to play and be listened to and added to by site
> 2 which is listened to and added to by site 3 ...  This
> would be a real-time equivalent of a multi-layer build-up
> of a number, just with no retakes!
> In both cases everyone involved would only be able to
> hear the finished result from a recording, not while
> they were playing, although in the latter scenario
> people towards the end of the chain would hear an
> almost complete version.

i suppose you could do this by setting up a "rat pipeline" so that 
sites 1 and 2 establish a unicast (or multicast) connection to one 
another where only site 1 has "talk" on, but site 2 talks through a 
second instance of rat connected to site 3 via a second unicast 
connection, etc.  

then site N pipes to a different multicast group node where the 
audience listens to the whole production.

perhaps it would be possible to do something similar with video to
include dancers (by shooting local dancers in front of rear-projected 
images from the pipeline), but repeated 261 video would probably degrade 
too quickly for more than a 3 step pipe.  however, it would also be 
possible for dancers to listen and perform in the audience venue....
though distributed dancers would not be synchronized...something that
might be as much an "opportunity" for creativity as it is a problem.

(oh, simulating these things in my head gets confusing...)

but wait...maybe this is another application for mark herald's personal
proxies operating as a means of overcoming transmission latencies to mars?


:michael grobe
university of kansas 

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