[ale] Re: webcams/videocams

[Geoffrey]

Thompson Freeman wrote:
> I haven't looked at the cpu hit, but I have a Kensington usb webcam. The
> price is nice, but there is zero dynamic range for useable light
> intensity. Pointed out the window, it is either too light or too dark to
> see an image except for two 5-10 minute periods of the day.

I'd be interested in your cpu usage with this camera.  I have used a 
couple of different cameras, and at one time did use them to 'monitor' 
my backyard through a window.  They all produced pretty decent images, 
considering it was snapping through glass and screen.  The yard was well 
shaded though, so I'm not sure if a large amount of sunlight would have 
made a difference.

> 
> Since you seem to have more experience with the hardware; do you have a
> clue you care to share about web cams, especially equipment which will
> tolerate wide intensity ranges while still producing a useable picture?

This is probably more then you bargained for, but....

I've got limited experience with a couple of configurations.  I've got 
two identical color cameras, I think they are mustek, called v-cams. 
I've got one b/w camera.  All three have rca connectors for both sound 
and video, although I've never done anything with the sound input.  I've 
got a bt878 chipset capture card and a wintv card that uses the bt878 
chipset as well.  The capture card has rca input, the wintv has s-video 
and cable.

I can connect any of the above cameras to either card, I have a rca to 
s-video converter for the wintv card.  The two v-cams also have a button 
on the back that's labeled 'shutter' with options of fixed or auto. 
I've not really found much use for it though, it does seem to lighten 
dark areas a bit when set to auto.  My only complaint regarding these 
cameras is that they seem to get pretty warm while on.  I don't see this 
with my other two cameras.

I've also got a quickcam express usb camera.  The v-cams and quickcam 
all have a ring you can use to focus images as well.  The b/w camera is 
really designed as a security camera.  The images are grainy (how do you 
spell that?), but it does well in low lighting, comes with a 60 ft. 
cable and is weather resistent.

I've also hooked up my sony camcorder via s-video and usb.  It obviously 
provides the best snaps.  I've only used the usb connectivity to mount 
the memorystick in order to retrieve images from it.  It's also firewire 
enabled.  I've had limited success with the firewire connectivity, but 
I've not had the time to devote to it.

I get pretty good snaps with the capture cards and cameras.  They seem 
to handle the lighting okay, although less light produces an image that 
is darker then you'd expect.  I can fire up xawtv with the capture 
card/camera and watch video just like watching tv.  That is I see no 
perceptible video loss.  Watching tv via the wintv is the same, and it's 
an extremely sharp image.  I see virtually no cpu load in this 
situation.  I've even played with a program called motion which snaps 
shots based on detected motion.  It works very well, although is a huge 
hit on the cpu (+90%).

The quickcam images are much grainier.  You are limited in resolution 
and just firing up xawtv with this device is a substantial hit on the 
cpu (50-60%).  Snaps represent the actual image, real grainy.  I would 
say that the quickcam is pretty useless for anything really.  I couldn't 
imagine what would happen if were to attempt 'motion' with the quickcam.

A while back I threw together a small page with comparisons of snaps 
from the v-cam, quickcam and I think a couple of snaps while watching 
tv, but I think I trashed it.  Nope, I found it, you can check the 
images out at http://www.3times25.net/cams/  Nothing pretty mind you, I 
didn't put a lot of time/effort into it. (the webpage or images)

> 
> Thanks.
> 
> (And I'll need to hook up that web cam of mine and see how big a cpu hit
> is puts on my system.)

I'd be curious to know.  I'm wondering whether it's the quickcam driver, 
usb or what.


-- 
Until later: Geoffrey		esoteric at 3times25.net

I didn't have to buy my radio from a specific company to listen
to FM, why doesn't that apply to the Internet (anymore...)?


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