Re:QuickCam Rate

Joe Hovel (jhovel@Protea.hitech.net.au)
Sat, 20 Jan 1996 10:51:58 +0000


> Hi all, I have been a little disapointed with my recently purchase
> quickcam. I was hoping to get some advice form a few of you out
> these...
>
> I have a PC version, and almost any movement is blurry. I tried most
> of the ideas in the FAQ and still to no avail. In my opinion I have
> seen nothing close to 15 frames a second. Andrew Stevens.

Hi Andrew,
the answer is almost certainly dependent on one of two things:
1.) The absolute limitation to video throuput for QuickCam on the PC
is the parallel port speed. If you have one of the newer ECD or EDD
ports, they are buffered better (to allow two way communication with
printers), then you should get somewhere near 12 to 15 fps in the
smallest window at 16 shades of grey..... earlier (slower ports less)
2.) processing video is very memory and processor hungry - if you have
a fast graphics card, then some of that load will be taken up there,
otherwise, the CPU has to do all of the pixel calculations and
allocations. With low memory configurations, there simply isn't enough
room to work on the first frame data and store the second frame data
for future work ... they are simply dropped until the space is
available again. I'm using QuickCam on a 486DX50 with 8 megs of ram
and an average video card through an enhanced port and get around 10
fps with a drop -oout rate on avi at around 30%. On my 496DX100 with
fast video and 16megs and ECD port I can get 12-15 fps with 15-20%
dropped frames (always 160x120/16 greys setting). On the company's
Pentium with "the works" and 32 meg RAM it's no better at all - which
probably means the port limits are reached by the 486DX100. I hope
that gives you some ideas for future upgrades..... Any further
questions, get in touch.