Perhaps you recall last year when Logitech launched their CC3000e Conference Cam? We had them as a guest on VUC 490 to show off their new gadget. The entire audience was impressed with the device, most especially the camera portion.…
Have you ever noticed that basically all webcams are connected to the host computer using the USB 2.0 bus? The ubiquitous USB 2.0 bus is cheap and convenient for such purposes. Providing 480 Mbps it’s no slouch, but it’s not exactly state-of-the-art either. This has implications when webcams are reaching for HD resolutions at decent frame rates.
Until quite recently webcams always provided an uncompressed image stream to the host computer. USB 2.0 is a serial connection standard supporting up to 480 Mbps. That’s about one third of the data rate of the production HD-SDI standard, SMPTE-292M, which is 1.485 Gbps.
Let’s do a little math corresponding to a 720p video stream as related to uncompressed HDTV.
8 bit/pixel @ 1280 x 720 @ 59.94fps = 105 MB per/sec, or 370 GB per/hr.
105 MB/s = 840 mbps
…but a lot of video conferencing gear actually uses 30 frames/second instead of 59.94 or 60 frames/second…so half that value…
720p30 = 420 mbps!
There you have it! The mathematics supports the assertion that 720p30 uncompressed “HD” video stream can be passed across the USB 2.0 serial bus. This explains how Skype, Google, ooVoo, VSee and others have been able to offer HD video using common USB 2.0 connected webcams. Understanding the limit of the USB 2.0 connection also informs us why 1080-capable webcams have not become similarly commonplace.
Last week LifeSize had a webinar on the topic of WebRTC. I took an hour to listen to what they had to say and pose a couple of questions. Their target audience appeared to be people who might have heard some of the hype about WebRTC, but were not otherwise familiar with this new phenomenon. Suffice it to say that the material covered was introductory.
The webinar started with a pre-recorded video of Casey King, LifeSize CTO and Simon Dudley, who is described as LifeSize video evangelist. Their pre-recorded conversation was followed by an audio-only live segment where they answered questions arising from the audience, which was reported to be over 1000 people.
If you care to view the event after the fact you’ll find a recording of the webinar here.
During the live event I posed a couple of questions in the text chat. I asked if they had any plans to support the Opus audio codec and VP8 video codec. These are core aspects of WebRTC, although the debate about whether VP8 or H.264 should be “mandatory” rages on.
Announced in December of last year, the GXV-3175 is Grandstream's latest entry into the multi-media phone arena. Reading the companies press release I thought the phone to be, in principle, a very ambitious undertaking. The GXV-3175 is a kind of…
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.
Video calling has been around for a long, long time. However, it’s yet to become commonplace. There have been studies, some very recent, that suggest that people really don’t want or need it. Yet Skype reports that a substantial amount, around 40% if I recall correctly, of their call traffic involves video. Of course, events like last years volcanic excitement in Iceland highlight how valuable video can be when travel is impossible.
Beyond the more general cases I have my own reasons why video could play an important part in my working life. It happens that I travel a lot in the course of my work. The scope of my working duties is divided three ways; pre-sales demonstrations of hardware/software systems, post-sales commissioning, installations & training, and finally end-user support activity. The demonstration aspect of my travel could be reduced significantly if I were able to deliver the demonstration via online means.