Re: Choice of quickcam

On Wed, 18 Jun 1997, Jean-Yves Simon wrote:

> Hi,
> Without speaking of the price difference, I am not sure
> which quickcam to buy, the b&w or the color one? 
> In windows, I believe they are well supported by connectix,
> but what about Linux ?

  The same thing - there are drivers for both, and a lot of them support
both cameras (including my qcread). The real differences:

1. B&W camera has one resolution (a bit more than 320x240) and two bit
depth modes (4 and 6). Color camera has two resolutions (>320x240 RGB and
pseudo-640x480 that really is 320x240 RG/GB pixels) and only one bit depth
in uncompressed mode.

2. Color camera has VIDEC compression that also probably uses lower color
depth, although since Connectix didn't release any libraries or
documentation, it's unsupported.

3. B&W camera is faster because it transfers less date (in 320x240 mode
it's 4 times for 6 bpp and 6 times for 4bpp). Significant, considering
that color camera has 0.8 - 1 fps in that mode.

4. B&W camera has fixed lens that work well for everything but extremely
close (inches) to the camera objects that require disassembling camera to
be readjust. Color camera has larger lens that should be adjusted
manually, although it also does'nt need adjustment for anything more than
2-3 feet away.

5. B&W camera has some strange-looking behavior of signals when it
confirms received requests while color one doesn't seem to have that
problem (but drivers handle that well in both).

6. Color cameras more prone to image fading problem that is caused by high
load on the box (longer transfer time contributes to it directly and
indirectly by having more context switching in it producing
horizontal lines with more fading below them if delays happen after some 
significant time since the grabbing started). Both cameras have this
problem, just color one has longer grabbing time.

7. In very poor light conditions and high exposure times color camera may
produce "christmas lights" as bright colored dots. B&W camera probably has
similar problem, but I never seen it.

There are two cameras at my home that are visible through HTMLs in
http://phobos.illtel.denver.co.us/pub/qcam/ directory, so you can see what
they show with the same light conditions and software. phobos is rather
small box, so if I can be seen at the images, it should have load about
0.1-2.0 that I usually have when working.