Marco van de Voort wrote:
On Wed, May 26, 2010 at 08:52:13AM +0000, Mark Morgan Lloyd wrote:
application running on Arm-Linux ?
Not recently I'm afraid. I got badly bogged down trying to use my one
development ARM system for both webcams- which meant I had to push it
onto Debian "unstable"- and FPC/Lazarus... I had the usual problems with
EABI etc. and ground to a halt.
Hmm, which webcam do you use?
Noting that we're talking Linux here: a number of not-very-recent (i.e.
cheap :-) USB ones which in principle are supported by SPCA. To be frank
I've only had acceptable results with a PCI BTTV card (badged Grandtec),
everything else tends to work over an extremely limited brightness
range- if at all. A couple of optical instruments are rather better (a
gooseneck endoscope and a Bresser microsocope) but I suspect in part
because the illumination level etc. is much more constrained.
I tried to post some more detailed notes the last time somebody was
asking about this, it was only later that I realised I was still trying
to send to the old server :-) In brief I think there are two sets of
problems:
i) Some drivers support v4l v1, and some v2: apps have to know which.
There's a shim .so which works round some of the issues but I don't
think the situation's been helped by code maintenance related to moving
SPCA into the kernel.
ii) Drivers almost always rely on register settings captured when the
camera is running under Windows. I suspect that in many cases Windows
drivers are aware of multiple submodels, so while Linux recognises a USB
camera by vid:pid it has no way of knowing that there are different ways
it can be tweaked.
I'd be happy to dig through my notes and code (C, I admit) but I think a
new thread would be in order.
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
--
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