Webcams: USB 1.1 vs 2.0

Logitech Communicate STX webcamShopping for a webcam is tough. I have significant experience with video cameras and video production in general, so I’m quite capable of comparing 3 CDDs to 1 CCD to 1 CMOS; juggling CCD sizes, lens diameters and what not.

Webcams are much simpler really. Their lenses are so small, it seems it ALL boils down to USB speed. At the same time, Logitech is known to play tricks on users, putting the USB 2.0 logo on USB 1.1 webcams. So I had to become an “expert” on the subject. Here’s what I found out:

Is USB faster? The truth is that USB 2.0 is not necesarily faster because USB 2.0 is simply a standard. It’s not a benchmark. Currently, there are three speeds for transfering data via an USB interface:

  • USB High-Speed – transfer speed of 480 MBits/second
  • USB Full-Speed – transfer speed of 12 MBits/second
  • USB Low-Speed – transfer speed of 1.5 MBits/second

The USB 1.1 specifications cover the full-speed and the low-speed transfer rates. So if your webcam (or any other device) is USB 1.1, it is using low or full speed.

USB 2.0 added the specification for a high-speed data transfer (480 MBits/second). There are MANY webcams out there, however, which boldly sport the USB 2.0 logo but transfer at speeds of 12 MBits/second or even lower. The fact that they’re USB 2.0 compliant doesn’t automatically mean they are high-speed.

To put this into perspective, HDV transfers at 25 Mbps; Panasonic’s DVCPRO HD supports speeds up to 100 Mbps. The end-users’ experience will also depend on broadband penetration.

For the record, I bought a Logitech Communicate™ STX today – a USB 1.1 webcam for test purposes. User-generated content – here I come.

Update: I was wondering what will happen if you hook a Panasonic HVX200 to a capture card and compare the stream to the one coming from a High-Speed USB webcam.