I think this is motivation to enhance the AG streams to use SSM - then you 
could select which source multicast streams you want to receive, which would 
permit those on low bandwidth connections to choose how to spend their 
bandwidth.

George Estes wrote:

     Being able to select which video streams to receive would definitely be 
helpful in our project to deploy PIGs to K-12 schools.  Many of these schools 
are bandwidth challenged.  We have been looking at ways to minimize bandwidth 
usage where needed and this would be excellent.

   George

   At 06:23 PM 2/1/2007 -0600, Piers O'Hanlon wrote:


      Hi,

      On 01/02/07, Joseph Stone <[email protected]><mailto:[email protected]> 
wrote:


         We've identified a need to have slow downlink participants be able to 
send
         their video but not receive video.  The idea here being that high 
downlink
         bandwidth participants will be able to see everyone who is 
participating.
         It's not enough to just not display the video for slow downers, the 
bridge
         needs to be told not to even send the stream at all.  It's enough for 
them
         to be seen and for them to have two way audio (highly compressed - i.e.
         GSM).


         Is there a current version of vic that will fill the need?


      There are a few approaches that we may be able to take:

      1) Modify VIC so that it does not join the multicast group - thus it
      should only send traffic into the network and not receive any video
      traffic from external sources. I'm not sure if this will work (though
      it should in theory - We can test it..) but we could add this feature
      fairly easily.

      2) The following two options depend on having wide deployment of a
      newer version of Internet Group Management Protocol (IGMP) - Version
      3. Unfortunately I don't believe it is - though it is seeing wider
      deployment.

      2a) UCL vic has recently included a new feature that allows one to use
      Single Source Multicast (SSM) - Which needs to be started using a
      slightly different command line. For video reception a separate vic
      will need to started for each video stream wished to be received.

      2a) VIC could be enhanced to actually take advantage of some new
      features - namely source based filtering. which would allow one to
      choose which video srcs one wanted to see.

      3) Another approach would be to use a special gateway or relay that
      allows on to filter/choose the sources recieved - there are a few that
      have featured in various AG retreats.

      I'd would like to hear if others are interested in such functionality.

      Piers.



         Joe


         On Jan 31, 2007, at 4:25 PM, Sam Gundry wrote:


         Hi Socrates,




         I actually commented out this line yesterday, before receiving this 
email.
         :)




         Video images now display locally in both the consumer and producer 
windows.




         What should that line of code do? I haven't noticed anything out of the
         ordinary yet...




         Thanks,

         Sam










         Socrates Varakliotis wrote:


         Hi Sam,

         I assume you're still building Vic on Windows.

         Can you comment out line 562 in tcl/ui-main.tcl and rebuild?

         #$target enable_xv $enable_xv"

         Let me know what happens then.

         Thanks,

         --

         Socrates.

         ----- Original Message ----- From: "Sam Gundry" 
<[email protected]><mailto:[email protected]>

         To: 
<[email protected]><mailto:[email protected]>

         Cc: "Piers O'Hanlon" 
<[email protected]><mailto:[email protected]>; 
<[email protected]><mailto:[email protected]>;

         "sumover-dev" 
<[email protected]><mailto:[email protected]>; 
<[email protected]><mailto:[email protected]>

         Sent: Tuesday, January 30, 2007 11:03 PM

         Subject: Re: [AG-TECH] Re: Compiling VIC in Visual Studio 8 (2005)









--
Bob Riddle (bdr @ umich.edu)            Enabling Technologies
University of Michigan Medical School   1301 Catherine Street
M4101 MSB1 - 6024                       Ann Arbor, Michigan  48109-0624

"Math illiteracy affects 7 out of every 5 people"

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