Looking over the H.323 Hill Bob Riddle Technologist, Applications Development 09 May 2001 See

A word about H.323  I like H.323  I use H.323  H.323 is a useful COTS technology that can be (and should be) deployed today  But …. H.323 is not the only interesting technology in the video conferencing world. H.323 does many things well but not everything well (at least not yet!)

Other Interesting Technologies  VRVS (the “open” videoconferencing system)  MPEG1, MPEG2 ( the here and now)  MJPEG (back to the Future)  DV/Firewire (HDTV - like for pennies)  Access Grid (think big!)  VIC/VAT/RAT Things that keep me awake at night

VRVS (the “open” videoconferencing system)  General Observations: Client agnostic video conference system – vic/rat, existing H.323 clients, Minerva Currently deployed in Physics community  Comparisons to H.323: Uses same video/audio codecs Software reflector versus hardware gatekeeper Windows, *ix clients available, Mac receivers Easily extensible (we have the source code!)

 General Observations: 1 – 3 mbps, free streaming clients available for broadcast & VOD events Many PC’s have built-in mpeg1 decoding appliances (VBrick) available  How’s it compare to H.323? video quality better than H.323 cost per sending station usually more than H.323 some interoperability between products but no standards govern transport like H.323 MPEG1 (here & now)

MPEG2 (here & now)  General Observations: 3 – 15 mbps, no free streaming clients hardware pricey ($10 - $25K per node) Interoperability between vendors non-existent know thy network (or at least the engineers!)  Comparisons: better than VHS quality, low latency, its wonderful when it works (kids, don’t try this at home) Little (or bad) multipoint support exists today

MPEG2 Traveling Node

MJPEG – Back to the future!  General Observations: 5 – 10 mbps, video quality similar to MPEG2 hardware cheap – but you gotta roll your own both software & hardware decoding clients are currently available from Berkeley – –  Comparisons: Great video, inexpensive, multipoint support Deployed today at Berkeley to support teaching Still work-in-progress, requires bandwidth

DV/Firewire (HDTV - like for pennies)  General Observations: 30 mbps, video quality better than MPEG2 – Promise of inexpensive high quality nodes – COTS: DV camera, player, firewire board hardware cheap – but …. – only working implementation is FreeBSD – some work on Linux (UW) but incomplete – Mac OSX work underway, anyone up for Win2K?  Status: Harder that it looks! (internal “race” problems) Current implementation is compelling (when it works!)

Access Grid (think big!)  General Observations: Group to group collaboration, persistent electronic presence, “Internet Café” 4 video inputs per node, virtual rooms Multicast required! 10-20mbs for a meeting COTS technology $40K for a node Need to know ALOT to get going  Comparisons: Video / audio quality about same as H.323 Continuous, multipoint presence is useful!

Mobile AG Node

VIC/VAT/RAT  Many good version of these tools freely available  Too many different versions of these tools freely available example: USB cameras work with openmash version but not VRVS version AG folks added nice usability functions not found in other versions User interfaces different – adds to confusion for users No one is minding the store (UCL)

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