Some might argue that the 1080p sensor results in better quality 720p video.

Thus it’s quoted as capable of “…720p HD Video Chat.” It does have a 1920×1080 image sensor, but it’s limited by the USB 2.0 host connection. Speaking of Microsoft’s own statements, looking at the Amazon listing for the device I see it described as the Microsoft LifeCam Studio 1080p HD Webcam. Microsoft’s own specs state “…up to 30 frames/second at 720p.” It cannot pass a 1080 video stream at normal frame rates to the host computer. The Microsoft LifeCam Studio webcam does have a sensor capable of 1080p resolution, but it’s still a USB 2.0 connected webcam. However, in the video they cite their use of “…Microsoft Lifecam Studio 1080p webcams.” Well, that’s a bit misguided. It’s a interesting video and I applaud how much thought they’ve obviously put into the tools that they use. For example, a year ago the Linux Tech Show posted behind the scenes video walk-through of how they produce their webcast, Category5 Technology TV. There is a little bit of confusion about webcams capable of 1080i or even 1080p. Understanding the limit of the USB 2.0 connection also informs us why 1080-capable webcams have not become similarly commonplace. This explains how Skype, Google, ooVoo, VSee and others have been able to offer HD video using common USB 2.0 connected webcams. 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. …but a lot of video conferencing gear actually uses 30 frames/second instead of 59.94 or 60 frames/second…so half that value…

Let’s do a little math corresponding to a 720p video stream as related to uncompressed HDTV.Ĩ bit/pixel 1280 x 720 59.94fps = 105 MB per/sec, or 370 GB per/hr.

That’s about one third of the data rate of the production HD-SDI standard, SMPTE-292M, which is 1.485 Gbps. USB 2.0 is a serial connection standard supporting up to 480 Mbps. Until quite recently webcams always provided an uncompressed image stream to the host computer. This has implications when webcams are reaching for HD resolutions at decent frame rates. Providing 480 Mbps it’s no slouch, but it’s not exactly state-of-the-art either. 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.

Usb 2 vs usb 3 picture quality