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Re: [SLUG] Security Video Cameras and Linux


not sure if this is what you want...
http://www.exploits.org/v4l/
http://www.lavrsen.dk/twiki/bin/view/Motion/WebHome

Ben


telford@xxxxxxxxxxxxxxxxxxxxx wrote:

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I have yet to find a good website talking about security cameras
and Linux (the hardware side that is). There are lots of software
packages and various odds and ends that work with v4l such as
frame grabbers, etc.

I recently bought a Logitech QuickCam Pro 4000 (USB) which is a nice
enough camera that is crippled under Linux because Phillips won't
release their proprietary compression algorithm. It will still give
640x480 resolution but NOT the full 1280x960 that it says on the box.
It seems hard to believe that they really have a cutting edge
compression algorithm that is genuinely valuable, more likely it is
just a matter of corporate disregard of Open Source and/or they have
infringed someone's software patent somewhere and don't want the
infringement to become public information. The other possibility is that the camera does NOT actually do any more than 640x480 but
the additional resolution is done by software interpolation (like
many scanners advertise a high "BS" resolution then a lower
"optical" resolution, aka the real resolution). I do notice that the
Logitech website says that the full resolution is only available for
still pictures and on some other cameras it does mention software
interpolation.

Needless to say, it would be good to avoid buying the Logitech
unless you want a crippled camera, but now the question comes up
about what DO you buy?

In the shops, there are no other USB cameras going anywhere near
1280x960 resolution in full colour. I can't understand why because USB2 has plenty of bandwidth and is hardly rocket science these
days but yet most of the cameras are around the 320x240 mark.

Another option is to go for a PAL capture card and a brooktree chip.
That works OK with a regular video security camera but the resolution
of regular video is still not much different from 640x480 so you
really aren't much better off. Most of the PAL cameras are from 450
up to 500 lines resolution and I would presume that the horizontal
sampling must be limited to something of the same order of magnitude
(even though analog cameras don't really have a horizontal resolution,
there is a limit to how much real detail is in the scan).

I've also looked at a few IP cameras and they cost a heap extra
for very little return (well, you can have longer cables than with
USB so that is one useful thing). They also have low resolution.

For example, a D-Link wireless camera selling for $500 is here:

 http://www.dlink.com.au/products/multimedia/dcs2100+/

Which has soooo many features -- except for a decent picture,
when you finally scroll down to the bottom of the specifications
it has only 320x240 resolution (which is squint quality).

So is the Logitech 4000 running in crippled mode considered the best
that you can get for a sane price? Is the crippled mode really the
best it can do in honest optical resolution anyhow? I bought the
logitech for $135 and probably would be willing to go to $200 if
I was getting something noticably better.

	- Tel





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