Re: QuickCam frame-rate

Alan Larson (EST)
Wed, 7 Dec 1994 13:39:34 -0500


Gary Vankirk (vankirk@koko.csustan.edu) asked:

> I'm just wondering if everybody else is getting the same thing I'm getting
> with the QuickCam; really S-L-O-W frame rate (on a PB165c) and a lot of
> "smearing" of the image? (This is with the included QuickMovie.) I've used
> the Video Spigot on a Mac II and it wasn't nearly this slow.

I have used the QuickCam as well as a Sony camera on a Video Spigot
on a Mac IIcx. My experience was much the same. The frame rate of the
quickcam was somewhat slower than the Sony camera, perhaps as much as a
factor of two (subjective, I didn't measure it). Since I was already
limiting bandwidth to 40 K, the slow rate was not a particularly
limiting factor for me.

The Video Spigot does run substantially faster, and with quite a
bit less load on the Mac. While running from the Spigot, the mouse
functions are still slow, but a lot faster than with the QuickCam.

The video does smear from the QuickCam, particularly if you are
over exposing the image and it sees bright lights. There is also
a tendancy for vertical bands of light or dark to appear as a result
of other picture components.

Careful adjustment of the exposure, and realizing that the QuickCam
has somewhat less dynamic range of brightness than a more expensive
camera, will allow one to produce good results. As with all video,
proper lighting is far more important than most people realize. A bit
of careful attention to good lighting (maintining reasonable contrast
ratios, instead of just bright) will result in quite reasonable
pictures from the QuickCam.

The camera looks very simple to use, but one still must pay attention
to some fundamentals to get very good results.

Alan