[sane-devel] Interested in writing a driver for...

Theodore Kilgore kilgota@banach.math.auburn.edu
Tue, 13 Apr 2004 18:40:29 -0500 (CDT)

Could I also mention that there is the gphoto project, which specializes
in camera support? If this camera is, like many others, a dual-use
webcam-stillcam, then it may (or may not) be supported already in
libgphoto2, for the stillcam functions. You can't always tell what is on
the inside by the name stamped in the plastic on the outside. Some chips
get used in 10 or 15 "different" cameras from "different" manufacturers,
which are not distinguishable from one another underneath the plastic

Unfortunately, however, it is not at this time possible to support the
stillcam and webcam functions with the same driver; the stillcam support
uses access via libusb, and the webcam support requires a kernel module to
be written. Further to compound the problem, if a camera is "dual use"
then the kernel module when installed will interfere with libusb access.

Is this camera a dual-use camera? If so, I am really interested, because
I am involved in stillcam support in libgphoto2. In any
case, what is its Vendor:Product number?

Theodore Kilgore

On Tue, 13 Apr 2004, Bertrik Sikken wrote:

> Greg Apessos wrote:
> > my Ezonics EZCam USB III webcam.  What got me interested was finding
> > a reference to the EZCam USB II not being supported on the
> > sane-project's site,
> > http://www.sane-project.org/unsupported/biolux-654.html.  While it
> > isn't a scanner, maybe my work could be useful to someone else.  But
> > the difficulty is I don't know how to approach the problem.
> >
> >> From the little bits that I've gleamed, I monitor the communication
> >> with
> > the camera on Windows, and get an idea of how messages are sent to
> > it.
> >> From that I start to build something useful.
> >
> > Are there guides, tutorials, something that could be helpful?  I
> > don't necessarily need step-by-step instructions, just an outline
> > like, program X will capture the communication with the camera,
> > library Y can be used to communicate with the webcam under Linux,
> > etc.
> >
> > Any help in the right direction would be great.
> program X = usbsnoopy. There is an 'old' and a 'new' (on sourceforge)
> version of this program. I personally like the old version, because
> it simply logs everything as text, which is easy to parse and analyse
> using scripts.
> I have a hacked version somewhere that does not log the USB bulk
> transfers. In some cases, this can help to reduce the log files
> a lot.
> library Y = libusb. I do not recommend to write a kernel mode driver.
> * First make really sure that noone else has already written a driver.
> * Try to figure out what kind of chip is used inside the cam and then
> look it up on google. Read the datasheet if you can find it.
> * Instead of starting on a sane backend, I would start with a very
> simple command line tool, where things are easier to control.
> * Let the world know you are working on support for the webcam.
> Probably other people already thought about working on this webcam,
> perhaps even figured out some stuff.
> Publish the stuff you find out on a website and post the address.
> If you have some actual code, consider starting a sourceforge project.
> Regards,
> Bertrik
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