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High Definition Video Conferencing: How High is "High" and What Exactly is That Definition

January 19, 2009 | Chris Payatagool

HD_photo.jpgBy Sagee Ben-Zedeff

"Generations come and generations go, but the earth remains forever..."

(Ecclesiastes 1)

In almost every other post in this blog, and maybe in any tech blog, in salesmen's pitches, the news, magazines and commercials - it's High Definition this, High Definition that. And ever since LifeSize announced the first ever High Definition endpoint in December 2005, the video conferencing market has gone HD-loony with "high definition" becoming a must-phrase in every discussion.

Q: So what, really, is High Definition video conferencing?
A: It's easy - "a video conferencing system using a high definition video".

Q: And what is "high definition video"?
A: Well, "High definition video" is a video stream of "a higher resolution than standard definition (SD)"...

Sagee_Ben-Zedeff.jpgThe above Q&A might sound like something out of a Monty Python sketch, but this is our reality. Advances in technology come and go, just like the generations King Solomon wrote about in Ecclesiastes, and yet the video remains forever. And just like the "next generation" product I am working on will soon become the "present generation", the "present generation" will become "legacy" and yesterday's "high definition" will be today's "standard definition". And "high definition", then, will always be the highest definition, the newest technology.

Not long ago (only three years!) CIF (352x288 pixels) ruled the video conferencing market. Back in the days of H.263, but even later when H.264 was introduced, QCIF and CIF were the standard and 4CIF (704x576 pixels) was dubbed "high resolution" or "full resolution". Thereby positioning itself as "the next big thing", with four times the "standard" resolution.

With advances in codecs (mainly H.264), networks, cameras and displays, LifeSize and its followers shook the ground under the feet of the market which slowly pacing towards 4CIF. It at once turned 4CIF into "standard definition" and crowned the next ruler of the video conferencing industry - 720p.

Video_OverEnterprise_lifesize_picture.jpgA picture is worth... 720p words? Source: LifeSize.

The video conferencing industry has long claimed that a picture is worth a thousand words. Yet it seems that just like TV was never a match to the cinema until HD screens and content came to the homes of everyone, visual communications in CIF were never a real alternative until high definition video became a reality.

But how high is "High"? Or in other words: what's high enough to be "High"?! When some endpoints from leading vendors (take HTC's Touch HD, for instance) use 480p (848x480), they are dismissed as "not really high definition". On the other hand, Skype has called its VGA (640x480) video "high quality", and got by. Microsoft's RoundTable also uses a 640x480 view for the active speaker, and a five camera setup which gives a panoramic view of the room at 1056x144 @ 15fps.

Remember George Ou from ZDnet arguing that "standard" definition at 1Mbps can actually look better than "high" definition at 1Mbps, as it is compressed less, and unless the pipes become fatter, HD won't win over SD? Well, the plumbers are working, and high definition has gone higher. The endpoints have been improved as well, and high quality 720p can be achieved at a little bit more than 1Mbps nowadays.

Original specs for present HD date back to the early 1980s when Japan's NHK developed Hi-Vision, an 1125-line TV standard at 30 frames per second. Current high definition video standards in North America are a technical descendant of the original NHK system and were developed by a FCC process, led by the Advanced Television Systems Committee (ATSC). FCC eventually adopted for HDTV an interlaced 1080 line video with a maximum frame rate of 30 fps and a 720 line video, progressively scanned, with a maximum frame rate of 60 fps.

Today's High Definition should be therefore defined threefold by the following:

Display resolution: at least 720p.

Number of frames per second: at least 25 or 30 frames per second (fps).

Bitrate: at least 1Mbps


Today, most HD video conferencing (HDVC) equipment supports 720p. Telepresence endpoints support 1080p. Most HDVC vendors will release 1080p endpoints this year (2009 that is; Happy New Year, folks!), and by the end of 2009 it will probably be the standard "high def". That will, of course, make 720p "standard", and so one can wonder what will be the "high definition" of tomorrow...

But what about 4-1080p?! The California Institute of Telecommunication and Information Technology (CalIT2) in San Diego already has a 100 Million pixel display wall and projectors that run at four times the 1080p resolution. This system requires, BTW, a bandwidth of more than 10Gbps.

xseed4000.jpgThe next big thing?! An illustration of the X-Seed 4000.

Generations come and (next) generations go, display resolutions go high and high-er, and there is never enough bandwidth or processing power. Consumers will always be on the hunt for the next big thing, with big being the main issue here, and so I guess the exact definition of "high definition" will keep forever evolving.


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