If you haven’t been using video conferencing, CP may mean nothing to you. CP, or Continuous Presence, is the most popular mode of display in a video conference. It means that some of the participants in the conference (or all of them) are displayed simultaneously in a mosaic (also known as “Hollywood Squares“), thus enabling each participant to see all of the other participants, as if they were in an actual (physical) meeting.
Now up until a year ago, most video conference users didn’t like the CP layout. That is because up until a year ago the most popular display resolution was CIF (352×288 pixels), which was, well, rather small. Don’t get me wrong – CIF is good enough for many video applications, including conferencing, in some cases (like desktop clients or mobile handsets), but to squeeze a layout with a bunch of squares in it into a CIF image and make it look, well, reasonable… that was a very hard thing to do.
About two years ago LifeSize became the first video conferencing manufacturer to introduce High Definition, or HD, into the video conferencing market. The HD revolution rocked the market. These days everyone is talking HD – the manufacturers, the resellers, the customers. Everybody seems to want bigger, because bigger is better. Well, you can’t argue when you see a video conference displayed on a huge LCD monitor at 720p (1280×720 pixels), especially compared with how video conferencing used to look like in the bad old days.
For me, bigger is indeed better, but mostly due to the fact that HD video conferencing goes hand-in-hand with the CP layout. Now this will require some math, but bear with me: If in traditional video conferencing you wanted to split a CIF image between, say, 9 participants, the size of each participant on screen was 1/9 of a CIF, or 112×96 pixels. This meant you could barely notice who they were. The whole purpose of video conferencing, to show face expressions and to keep the experience as close to llife as possible, was gone.
But with HD resolution, 1/9 of 720p is… CIF. This means that if someone joins a conference with a standard definition endpoint (sending CIF or 4CIF), they will appear in their native resolution (or close to it) and look on the CP layout as sharp as they look on their camera. If someone connects using a high definition endpoint, and is scaled down to 1/9 of the original image, they will still look great.
So in the HD video conferencing world, the CP is truly the best experience – you get to see everyone, while still enjoying the fine details of each participant. Every time I watch such a conference on one of the big screens that are present in RADVISION’s conference rooms, I can’t help but sneak a little smile. CP is back, equipped with a HD display, and the match between these two is a match made in (corporate) heaven.
6 participants in a CP layout displayed in 720p as displayed on Scopia Desktop