Is my USB broadcast going to be bogus?

December 19, 2005 10:17 PM

And on the subject of USB, I just bought parents a webcam for Christmas - the idea being that I buy one too and then we can see each other during our weekly chat. The problem I've just realized is that my Thinkpad (X22) isn't USB 2.0, so is that going to make the broadcast from my end unbearably slow?

Yeah, I could buy a USB 2.0 PCMCIA card, but I only have one slot and that's where my wireless card lives.

So is this bad, and is there any way I could possibly make it better?

posted by russmail to computers & internet (8 comments total)

No, 11mbps is way more then you need for webcam chat. Remember, it needs to get compressed and sent over the 'net anyway.
posted by delmoi at 10:23 PM on December 19, 2005

You could also just test the camera first and see if it works.
posted by delmoi at 10:24 PM on December 19, 2005

>the idea being that I buy one too and then we can see each other during our weekly chat.

Unless I'm misreading this, you're saying you're going through some kind of WAN connection (the internet) which of course involves tons of compression and is the real bottleneck here, not the interface from the cam to the PC. Your videoconference software along with the speed of your upstream internet connection is going to determine how well the graphics look, not the USB interface.

For instance, if I have 128kbps up then my videoconferencing software is going to have to work with that severe limitation. That's kilo-bits per second. USB devices work on megabits per second. So you're going to be tossing and compressing a lot of that webcam data anyway.
posted by skallas at 11:38 PM on December 19, 2005

USB 1.1 web cams generally suck, but they do make and market such things (or at least they used to). There's a reason the iSight is firewire: even USB 2.0 has trouble keeping up with decent video.

But you have to compress the video and make it postage-stamp size to send it over the internet, anyway. BUT: that video is compressed on the fly -- if the camera can't get it off the USB bus and to your processor quickly enough, that's where you get problems, I guess, because is my experience USB2 and Firewire cameras are considerably better than USB1 cameras.

I have a USB 1.1 3Com web cam, and it has a real problem doing decent video at the 12 Mbs that the USB bus offers. Generally, the video had to be very heavily compressed, and it needed to be around 300x200 with that model.
posted by teece at 2:22 AM on December 20, 2005

I get fine live video off my USB 1.1 camera.
posted by cillit bang at 2:36 AM on December 20, 2005

OK - so here's a follow up question: is it going to be problematic using a 2.0 camera with a 1.1 bus? Am I better off trying to track down a 1.1 camera?
posted by russmail at 10:35 AM on December 20, 2005

USB 2.0 devices are required to be backwardly compatible with 1.1. You shouldn't have a problem, assuming that the camera is fully compliant with the USB spec. When buying USB devices, always look for the official USB logos on the box or documentation. This guarantees that the device has been thoroughly tested for USB compliance.
posted by JackFlash at 11:42 AM on December 20, 2005

Although what Jack said is technically true, a USB 2.0 camera may not stream properly down a narrow 1.1 connection. It shouldn't be too hard to find one.
posted by cillit bang at 12:01 PM on December 20, 2005