[AG-DEV] Re: [AG-TECH] AccessGrid 3: What information is available

[Andrew Rowley]

> 
> >         * Multiple video inputs to Vic (which would remove the necessity
> >         of multi-machine nodes)
> 
> as i understand the current ag architecture, it wouldn't really
> be possible to take advantage of a multi-input vic since there
> is a 1-to-1 mapping of "resources" (i.e., video capture devices)
> to node services.  if that is incorrect, i'd be interested in a
> clarification.
> 

My understanding of this is that currently users usually have one machine
that sends all the video streams for their node.  In some situations this is
also the audio and/or display machine.  In order to send four video streams,
this machine must have four transmitting vics.  This means four windows open
minimum which are just for transmitting.  Each of these vics must
additionally receive the all the video streams from the session, although
these are muted.  I am unsure of vic architecture, but I imagine muting does
reduce the processor load somewhat.  In any case, there are four windows,
where there could only be one if vic could handle multiple camera inputs.

Where the machine is also the display machine, there is also a vic for
receiving input streams.  This makes it more complicated for users as they
have to work out which is the actual receiving window.  I have often heard
complaints that users cannot see any video, when actually they have just
picked a vic with all muted streams.  This becomes an even greater problem
for unicast users, as the incoming video will only appear in one of these
vics, which might be one of the ones that it muted.

In summary, it would be useful to have a video tool that sends and receives
all the video streams so that only one instance need be opened on any
system, and that instance will cope in both a unicast and multicast
situation.

Andrew :)

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