Comments on: USB High Definiton Webcam: How to record?

Question: USB High Definiton Webcam: How to record?

bryanjbusch — Fri, 17 Aug 2007 12:00:34 -0800

How do I record high definition (HD) video at at least 24 fps using a webcam?

I bought (and then returned) a QuickCam Fusion webcam, which was designed to enable video conferencing at up to 960x720.

It transmits over USB, and works well in iChat (Mac OS X), and with the included software I tested on a separate Windows computer. But iMovie doesn't recognize it, I suspect because it's not Firewire.

Recording through QuickTime resulted in a video playing at only 7.5 fps, and recording in iChat (using the 3rd party "ConferenceRecorder" app) gave me a resolution barely bigger than 640x480.

Recording in Windows also resulted in a video playing at about 7.5 fps.

Am I trying to cheat physics, here, or is there a way to record the video that plays live at 960x720 + 30fps?

By: bryanjbusch

bryanjbusch — Fri, 17 Aug 2007 12:02:49 -0800

I should add for the purists in the audience that I don't care if the video doesn't end up being 1280x720. Most likely, I'll be aiming for a final product of 960x540, but it should still be possible to do 960x720 if I want.

By: mzurer

mzurer — Fri, 17 Aug 2007 12:13:16 -0800

No, you will not be able to do that.

By: mzurer

mzurer — Fri, 17 Aug 2007 12:21:50 -0800

To elaborate, the product is not designed for that. A cursory look at the Logitech web site says it can record video at 640x480 and "up to" 30fps.

By: fake

fake — Fri, 17 Aug 2007 12:38:20 -0800

Yeah, you're limited by the speed of the bus/USB chipset and the sensor itself, not software. It can do still captures in "HD" but not video.

By: bryanjbusch

bryanjbusch — Fri, 17 Aug 2007 13:09:17 -0800

So does that mean that no software on Earth could ever capture video from a camera attached to USB at > 480 pixels tall and > 24 fps?

I can accept that, I suppose, but I just want to be clear that there's absolutely no avenue to pursue, here.

Is Firewire the only option? Isn't Firewire kind of dying a slow death?

By: chunking express

chunking express — Fri, 17 Aug 2007 13:26:44 -0800

Firewire is awesome. I don't think it's going to disappear anytime soon.

Also, you really can't expect a web cam to perform at the same level as a proper HD video camera.

By: mzurer

mzurer — Fri, 17 Aug 2007 13:53:51 -0800

Firewire is not likely to help you that much. If you want HD you need an HD camera. And then you need a hard drive array capable of keeping up with an HD data stream. You might be able to get an HDV camcorder and take a line out of that and you might be able to record the video from the firewire stream.

Why do you need it to be HD? Note that your existing camera can't even do Standard Def video.

By: adipocere

adipocere — Fri, 17 Aug 2007 14:46:32 -0800

Do the math. 960 x 720 x 3 color bytes per pixel x 30 frames per second = 62.2 megabytes per second, uncompressed. That would be a bit beyond even USB 2.0, which can only go to 60 megabytes per second.

I suppose it's theoretically possible that the firmware on the cam could do some kind of basic compression before shooting the video to you, bringing you in range, but my guess is that you're not gonna get that. It's a webcam, not a movie cam. Feel like writing drivers and fiddling with firmware which may or may not exist? Might as well be "no software on Earth," for your purposes. On top of it, you'd need a decent drive array to keep up with that unbuffered output, which is gushing like a firehose.

In any case, if you're trying to shoot video with a webcam, being cheap is not going to help.

By: bryanjbusch

bryanjbusch — Fri, 17 Aug 2007 15:10:05 -0800

Oh, well. I thought I had found a way out of paying six times as much for a camera. Thanks, everybody.

By: filmgeek

filmgeek — Sat, 18 Aug 2007 06:04:15 -0800

HD Video has three major bit rates worth mentioning.
25 Mb/s (HDV and the MPEG4 version of such)
100 Mb/s (DVCPro HD)
625 Mb/s (Fully uncompressed).

The HDV version works (and the DVCPro HD version) as they're compressed on camera.

And by the way, full 720p is 1280x720 at 60 frames per second (even the DVCpro version is 960 with nonsquare pixels.)

Anyway you cut this, you're talking about tons of compression and moving buckets of data.