It was around a year ago that went on the hunt for a USB 3.0 webcam, only to find that they were essentially nonexistent. In my quest what I discovered was a range of products beyond the familiar consumer webcams. These are serious webcams for business, offered by companies like VDO360.
That companies’ initial product, the VPTZH-01 HD USB PTZ Video Camera, was novel for its VISCA compatible pan-tilt-zoom (PTZ) capability. It was introduced at around $1399, a price that was heralded as a breakthrough at the time. Award-winning in fact. The current street price, as exemplified by Amazon, seems to be $999.
The VPTZH-01 HD USB PTZ Video Camera is a USB 2.0 connected device, with all that entails. The sensor is capable of delivering images up to 1920 x 1080 pixels (1080p.) Most applications will only manage to access a 1280 x 720 pixel (720p) stream since they are taking uncompressed frames from the camera.
Applications that are sophisticated enough to setup the camera to deliver a stream of MJPEG compressed images will be able to get full 1080p quality for the effort. The MJPEG compression overcomes the bandwidth constraint of the USB 2.0 connection to the host computer.
It’s come to my attention that in recent times “Surround Sound Bars” have exploded in popularity. That’s “sound bar” as in a form of home-theatre-sound-in-a-box, not a smoky dive where musicians perform strange music. Sound bars are now so popular that they are impacting sales of more traditional HTIB solutions. I’ve come to see some parallels between surround sound bars and DIY video conference room systems, an idea that first came up earlier this year.
As I have mentioned previously, we don’t have a traditional surround-sound system in support of our HDTV. Our 42” Sharp Aquos HDTV was the largest that they offered with built-in speakers…which is all that we felt we required at the time.
In truth, it was the display size and resolution that mattered most when we made the purchase decision. In the middle of the last decade most 40”-ish HDTVs still only resolved 720p. Since my Mrs tended to watch more CBS than the other networks it made sense to get a HDTV capable of resolving 1080i.
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.
Prognosticator extraordinaire Dave Michels recently post some observations of things he saw at InfoComm. In so doing I think that he may have coined a new buzz-phrase, “DIY Room Systems.” I must admit that I am smitten with the concept.
For those not versed in enterprise video conference jargon a “room system” is a video conference end-point of the sort that might be found in a meeting room. That covers a broad swath of territory, basically everything between desktop video conference clients and telepresence suites.
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.