On 10/03/2007, at 4:55 AM, Bruce Curtis wrote: > > On Mar 9, 2007, at 8:55 AM, gurcharan khanna wrote: > >> All, >> >> I think sending all stream types is a great idea, so the receiver >> can choose the resolutions >> needed. >> >> A related issue is bandwidth limitations. If I choose to receive >> 261 instead of HD for that >> reason, then I may not be able to tolerate all those bits on my >> network. So, then the issue >> becomes, how do I tell the source not to even send me the HD >> stream for instance but only >> the 261 streams? If the HD and 261 are two separate modules, then >> that would work. If they >> somehow are all integrated, maybe then that becomes a problem? >> >> -gurcharan > > Two ways to allow the receiver to choose between the streams > would be to > > 1. Send the streams in separate multicast groups. > > 2. Use Source Specific Multicast (SSM) and source the streams > from two different unicast source IP numbers.
Gurcharan, Our current plan is to use the first of these methods that Bruce mentions. A twist on the AG toolkit's built in dynamic address allocation mechanism for new stream types makes this possible. Each new DV or HDV Producer is allocated a new multicast address. Any new DV or HDV Consumer is given a list of streams to choose from _before_ subscribing to any of them. That means that for DV & HDV, there'll be a separate vic instance for each video source being viewed (as distinct to the default H261 video services which show all available video sources for a venue in the same vic instance). This is all sort of working now, but there is a problem with VenueClients up to v3.0.2 not being updated with new stream information after initially entering a venue; that will be fixed for AG 3.1. chris >> Christoph Willing wrote: >>> >>> On 09/03/2007, at 3:49 AM, John I Quebedeaux Jr wrote: >>> >>>> Someone asked me about this camera for HD use on the AG: http:// >>>> www.picturephone.com/products/sony_evi_hd1.htm >>>> >>>> Anyone have any experience with it? I'm wondering if it was >>>> used, how to best "capture" it into a system for use on the >>>> AG... interest in using HD is high here. I'm more concerned >>>> about logistical issues with high resolution images on displays >>>> that don't have that much "resolution" space - particularly if >>>> several sites are involved. >>> >>> >>> John, >>> >>> With regard to screen space logistics, we've developed a version >>> of vic that does DV and HDV - full details and perhaps a demo at >>> the forthcoming AG Retreat. One of the changes is the ability to >>> resize the video window(s) to any size you like. Thus you could >>> accomodate several streams at smaller than true HD size when >>> display space becomes tight. >>> >>> BTW, I think that when DV, HDV, HD are all more common in the AG, >>> best practice will be to always send those formats as duplicates >>> of standard H261 streams so that other sites can choose to view >>> their own preferred mix of H261 and higher resolution formats >>> (somewhat avoiding the screen real estate problem you raised, not >>> to mention bandwidth issues). The cameras we've been testing with >>> have a number of simultaneous outputs available so its trivial to >>> send both DV/HDV and H261 at the same time. >>> >>> >>> chris >>> >>> >>> Christoph Willing +61 7 3365 8350 >>> QCIF Access Grid Manager >>> University of Queensland >>> >>> >>> >> >> -- >> ------------------------- >> Gurcharan S. Khanna, Ph.D. >> Director of Research Computing >> Office of the Vice President for Research >> >> Director, Interactive Collaboration Environments Laboratory, >> Center for the Advancing the Study of Cyberinfrastructure >> --- >> Rochester Institute of Technology >> 1 Lomb Memorial Drive >> Rochester, New York 14623-5603 >> Phone: 585-475-7504 ~ Cell: 585-355-1603 >> Email: gurcharan.kha...@rit.edu >> Http: www.rit.edu/~gskpop >> > > > --- > Bruce Curtis bruce.cur...@ndsu.edu > Certified NetAnalyst II 701-231-8527 > North Dakota State University > Christoph Willing +61 7 3365 8350 QCIF Access Grid Manager University of Queensland
