Experiments With Vidyo
In recent weeks and months I’ve been giving some thought to making greater use of video within the scope of my work life. In part this is what what motivated my ill-fated attempt to get LifeSize to appear on a VUC call. It happens that others VUC contributors are considering such things as well.
Last week Paul Warmbowski was completing a trial of the Vidyo personal telepresence server. He offered several VUC regulars a chance to connect for a test call. The experience was both welcome and very interesting.
The Vidyo client was a download that runs right in the browser. I must say that I was impressed. The video quality was good, but that was just a starting point. The client allowed for dynamic changing of the windows layout. It could be taken to full-screen mode or left as a window on the desktop. It supported desktop screen sharing on an application basis.
The Vidyo client found my Logitech 9000 webcam and Clear One Chat 160 USB audio device. When I plugged in the USB dongle for the Voyager Pro UC it let me select that audio device without leaving the conference.
My relatively modest two year old HP desktop seems happy enough to run the client full screen (1920×1080 pixels) without feeling overly burdened. The Vidyo client defaults to an automatic quality setting that trades off frame rate against spatial resolution. It seems like most of use were getting 854 x 480 pixels at 15 frames/sec.
Since my Logitech camera support 1280 x 720 pixels (720p) I tried to force the Vidyo client to use the camera in that mode. Only then did it seem to really tax the humble host desktop.
Vidyo has taken advantage of H.264 SVC…which means “Scalable Video Coding”…in offering their products. The principle underlying SVC is that you can create a video stream in layers, such that any particular end-point need only extract and decode those layers appropriate to its capabilities. It’s also supposed to address issue such as packet loss in the network.
I won’t go into the details of SVC right now, but here are some background links on H.264 SVC.
It was an interesting experiment. Thanks for putting it together Paul!
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I did some testing with a sales engineer on the resolution/ frame rate. It seems that the client software is deciding what to receive based on cpu usage as well as bandwidth, and even though they spec a minimum of Core2Duo for using Vidyo, I found that you need more to maintain a good HD conference. I noticed when I forced 30fps in my macbook (core2duo), it would go to 90%cpu for a bit then drop again to 15fps at about 50% cpu. (BTW – If I had lots of other processes running at the same time it would drop even more). In contrast, my Core i7 Windows computer could handle as well as maintain receiving 720p at 30fps while using only about 25% CPU. I guess maintaining HD in a VidyoConference requires a pretty current computer at each endpoint. Which makes sense, as the endpoints are doing the compositing in the SVC architecture.
BTW – I found a couple of outfits that offer Vidyo as a hosted service for around $20/user/month. I would have to say, that the hardware that they sell seems tailored to service providers. And I would expect more to be popping up using this technology. I know that Google uses it for their voice and video service, and I have seen that it is being integrated into Adobe Connect.
-Paul