Wesley Alan Wright: Notes, Lessons, and Projects

Faculty member needs to give a talk remotely at U of malta, has some questions. For future reference, here’s my answer

Video conferencing is still way more difficult to use, or even understand, than it should be.

First, let’s clear up some terminology:

H.323 – a communications protocol standard, which negotiates audio/video capabilities and establishes the audio/video media streams. The term "h.323" is generally used to refer the set of protocols used during the signaling process and the streaming of media. The basic idea is that any h.323 compatible product can communicate with any other h.323 product. h.323 is also specific to communications over the internet

H.320 – The original ISDN videoconferencing standard. Pretty much the same as h.323, but over dedicated telephone lines rather than the internet.

codec – stands for COMpressor/DECompressor. Television and video contain far too much information to send across the internet unless it is compressed at the sending end and decompressed at the receiving end. The codec refers to the method used to compress and decompress the audio and video. There are dozens of different codecs, and both parties trying to communicate must be using the same one in order to communicate. Some codecs are implemented in software; others are built into dedicated hardware. One of the jobs of h.323 compliant products is to make sure both parties are using the same codec.

H.261 – a video codec for fast internet connections (>=3D 64kbps)

H.263 – a video codec for slow internet connections (< 64kbps)

H.264 – "an ultra-efficient new video codec called H.264. H.264 delivers stunning video quality at remarkably low data rates, so you see crisp, clear video in much smaller files. Chosen as the industry-standard codec for 3GPP (mobile multimedia), MPEG-4 HD-DVD and Blu-ray, H.264 represents the next generation of video for everything from mobile multimedia to high-definition playback. Numerous broadcast, cable and video conferencing groups consider H.264 the video codec of choice for their deployments." (Apple web site)

NetMeeting – an old, officially discontinued Microsoft product for video conferencing. NetMeeting is H.323 compliant.

OhPhoneX – an experimental, limited feature H.323 product for the Macintosh

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When Steve Cavrak said, " At first blush (mine), I think Tiger will do it for us !" he was referring to the inclusion of the H.264 codec implimented in software (QuickTime 7) as part of Tiger. By itself, H.264 does nothing.

Tiger does include a next generation iChat client, but iChat does not use H.323 (it uses SAP, another protocol standard).

So, when Michael Caruana says

Video conference should ideally be held over H.323 (that is, over the data network and not over ISDN telephony)

He means, "Use an H.323 compliant product, because that’s what we are using and if you don’t, we can’t see you and you can’t see us because we are using different standards."

and when he says

What is important is that you must have a dedicated video-conferencing codec (nothing to do with the Macs or PCs). Does your department offer video-conferencing facilities? This is important to establish a high-quality audio-video link.

He means, "For the video ONLY — the most important part — don’t just use any old H.323 product (like OhPhoneX or NetMeeting) on a PC or Mac, but rather use a dedicated piece of specialized hardware, like these here from Polycom

http://www.polycom.com/resource_center/0,1454,pw-7059,FF.html And when he says

I’m not sure re: Macs…will have to check from our side too. I suggested Microsoft net meeting for the data sharing part (i.e. >> sharing Power Point separately from the video conference itself).

He means Use NetMeeting, but just for the Powerpoint slides. This is a feature of NetMeeting that falls outside of H.323 standard. OhPhoneX for Macintosh does not have a similar feature. In fact, most H.323 products don’t have this feature.

Somebody — I’m not sure who — said:

Please ask whether your establishment offers dedicated video conferencing services. Perhaps the Computing Services there might be able to help you. If you do not have any such services available, then > we can always try and connect anyway, but I have my reservations on > the quality projected here. A test should give a fair idea. How do you normally connect to colleagues? Do you enter some sort of number similar in format to: 193.188..42.1

Yes, our establishment does. Contact Wes Graf at instructional TV services . They have fancy TV cameras attached to VTel brand hardware codecs. This would satisfy the them-see-you part of the equation. They can hook up some computers in such a way that a technical director switches between your face and your slides. They might be able to handle the NetMeeting part, too, such that one screen in Malt shows your face and the other shows you slides via NetMeeting.

Wesley Monteith Graff III
Wesley.Graff@uvm.edu
Manager Instructional TV
Continuing Education
232 Rowell N/A Hlth
(802)656-4213

they charge real money: $55 per hour.

You could use ohPhoneX for the Macintosh, but then Malta won’t see the slides.