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View Full Version : Slo-Mo Webcam? Or is it the the CPU?



10-10-2001, 01:07 AM
I just got an Acer DSC 300 digital still/video camera in the mail this morning and it takes excellent pictures (for a 640x480 CMOS anyway...). But the webcam feature has left me a bit disappointed. The camera is capable of 30fps, but when I'm using it in that mode it runs at about 1fps or worse, no matter what the resolution. I'm running a Celeron 450, with 128Mb RAM and Win98, have all the latest drivers, and have tried running the video software with all background apps closed. It seems to run at the same rate in NetMeeting as well as its supplied program. Is it my machine, or is there some way of tweaking the speed on the USB port? Apart from that its a great little camera, and I'd recommend it as a fun webcam & tin-pot digital camera for anyone (avail at ascent.co.nz)

10-10-2001, 01:54 AM
Is this when your using it over the internet? Unless you have a very fast connection, your going to have to use very low quality video.

Also at the high quality it may be too big for your processor to handle as it has to also compress the video before it sends anything.

10-10-2001, 07:55 AM
Most webcams support up to 640x480. Most of them are slow at this resolution, designed mainly to capture your dial to put on your webpage, at a decent quality.

10-10-2001, 09:40 AM
I haven't tried using it over the internet yet, I'm only running it directly on the PC through the USB port, with no transmission online. I've tried it at every resolution the camera is capable of, down to 160x120; all with the same results.

10-10-2001, 05:03 PM
Let's do some arithmetic. 640x480 makes 307200 pixels. If the camera is b/w with 256 grey levels, that makes 2.4576 megabits/frame. If it is a colour camera using three times the bits/pixel that comes up to 7.3 megabits/frame. Allow for USB overheads and whatever the CPU is doing ... 1 frame/sec seems to be pretty good.

10-10-2001, 06:09 PM
The reason I made this post is because I've seen webcameras give excellent almost DV like performance on computers before, and I had thought that it would run satisfactorily under my system configuration. As I said, I have tried all the different resolutions the camera outputs, and all of them work at ~1-2fps. This problem is independant of the cameras resolution. If the camera could only run at 1fps, why do makers bother making them capable of 30fps? There has to be some reason why its operating so slowly.

10-10-2001, 06:34 PM
UPDATE: I got it working just fine, a great frame rate at any resolution. The weird thing is, all I did was change it to a different USB port. Is there any reason why one port should run slower than the other?? My MBoard is an ABIT BH-6 if anyone has any suggestions about whats going on...