Picturetel Info

They have a room set up with suitable acoustics and lighting. The big Picturetel has connections to the Ubiquity broadband network as well as ISDN. The controls allow several sources to be connected - currently the main camera, document camera and 35mm slide converter. There is also a jack where they connect a laptop PC with VGA->NTSC converter for showing powerpoint slides etc.

This picturetel replaces the original one which used proprietary coding and would only talk to a similar machine. There is also an Eclipse unit by CLI which only uses QCIF (quarter-size pictures), and was unable to communicate with the LLNL switch. It also has a proprietary CTX coding which offers some improvement when talking to similar units.

The Eclipse audio setup that I saw had 3 codings - G.728 which may be the same as vat "gsm", G.711a which is probably an A-law coding, and G.711m which is probably the same as vat "PCM" 78Kb/s 8-bit mu-law encoded 8KHz PCM.

The video setup is H.261 on both machines. ivs supports the Super CIF (704x576 pixels) format or CIF (352x288 pixels) format or QCIF (176x144 pixels). By default, format is QCIF.

Videoconferencing Room with Picturetel 4000

One interesting tool is the little pyramid on the table, which is a UHF Infrared repeater, with a range of 200 feet. You point an IR remote control at one unit, and its twin sends IR to the Picturetel (or VCR, TV, etc.) in a different room.

Main Camera with remote zoom, pan, tilt capability.

Control Panel

Document Camera

Picturetel 4000 with ISDN interface on top.

More Notes

• The table-mount microphone picks up noise from people putting coffee mugs, etc.down.
• The video codec is fine for fixed background. It blurs people's heads as they talk. The camera must be solidly mounted else everything blurs for several seconds if it moves.
• The document camera is used about 50% of the time. It has good lights and zoom capability, but like the main camera takes a few seconds to become readable after someone moves the document or nudges it with a pointer.
• One can't use the discount phone carrier as they can't guarantee a digital path to the USA every time.
• Showing anything detailed is fairly hopeless. Documents are best transferred beforehand with ftp/http/email, then when the guys at the far end put their copy under the camera and point to it, you can look at your copy to see what they're pointing at. Fine lines, such as table boundaries, can give odd moire effects.
• There's only one video channel (cf. Mbone tools). UBC has 2 monitors to preview the document camera and outgoing video (pre-compression), and the big TV can put one of these as Picture-in-Picture. I don't think the PiP can be transmitted.
• Video feed is voice-switched. UBC end has a mute button to prevent local chat being transmitted
• Lighting, acoustics are important. Striped shirts give colour moire effects - professional TV people know all about this kind of thing.
• Having the camera above the TV at a distance from the participants doesnt give the "good shot of eyelids" problem of a personal above-monitor camera.
• Having a nameboard that appears on the bottom of the outgoing video is probably a good idea. UBC has a "UBC" one, of course. SLAC has one.
• The sound is pretty good, probably better than an analog phone line.

References

• QuickTime Conferencing
• Video conference hardware FAQ
• Video conference standards FAQ