Re: [Linux-uvc-devel] Test of the driver on GNU/Debian amd64

[<Oli...@id...>]

Hi Laurent,

> I've contacted Logitech a few months ago, and they were very
> interested in the project. Linux is clearly a market they can't ignore
> anymore, but they currently don't have development resources to assign
> to Linux drivers development. They offered their help and are very
> supportive.

Cool. It's a good start. Hope they have given some webcams to you. :-)

> I created a linux-uvc directory on purpose, as the project is very likely to 
> release more software soon (sample SDL V4L2 viewer for instance, or patches 
> for software like usbutils, GnomeMeeting or Kopete). I planned to organise 
> SVN in way similar to this :
> 
> linux-uvc
>   linux-uvc		(Kernel driver)
>     branches
>     tags
>     trunk
>   uvcview-sdl		(SDL-based UVC viewer)
>     branches
>     tags
>     trunk
>   uvcview-qt		(Qt-based UVC viewer)
>     branches
>     tags
>     trunk
>   patches		(Patches for GnomeMeeting, Kopete, ...)
> 
> If that's not a good idea, feel free to kick me :-)

No, it's a good idea... Maybe just add linux-uvc/trunk directly, which
will include all the "sub-projects". So, you will have something like
this:

linux-uvc
  trunk
    linux-uvc    (a link to linux-uvc/linux-uvc/trunk)
    uvcview-sdl  (a link to linux-uvc/uvcview-sdl/trunk)
    uvcview-qt   (a link to linux-uvc/uvcview-qt/trunk)
    patches      (a link to linux-uvc/patches)
  linux-uvc
    branches
    tags
    trunk
  uvcview-sdl
    branches
    tags
    trunk
  uvcview-qt
    branches
    tags
    trunk
  patches

After that, you can retrieve the full tree using the berlios
instructions.

> > Attached patch uvc_v4l2_read.patch correct this warning.
> 
> Applied.

Great. :-)

> I'm developping on a Gentoo box, and the module is installed in the correct 
> location. If there's an easy way to fix the Debian problem without breaking 
> other distributions, feel free to send a patch.

It's not a big problem for me at this time... Maybe I will look at it in
the future...

> > Then, I have try to access the camera with camstream, without success:
> >
> >   CVideoDevice::CVideoDevice() could not query capabilities; is this
> >   really a video device?
> 
> camstream uses the deprecated V4L1 API, and the UVC driver only support V4L2.

OK. So, no camstream.

> > Accessing the camera with OpenCV
> > (http://sourceforge.net/projects/opencvlibrary/) also cause problems...
> 
> Same problem.
> [...]
> You will have to implement V4L2 support in OpenCV.

OpenCV has support for both V4L1 and V4L2 since mid September 2005...
But it has maybe some problems with the implementation. (I have just
found one now...).

The main problem with OpenCV is the support for V4L2_PIX_FMT_YUYV and
V4L2_PIX_FMT_MJPEG. These formats are not supported at this time. The
supported formats are V4L2_PIX_FMT_BGR24, V4L2_PIX_FMT_YVU420,
V4L2_PIX_FMT_YUYV, V4L2_PIX_FMT_YUV411P, V4L2_PIX_FMT_SBGGR8,
V4L2_PIX_FMT_SN9C10X.

I will see if I can add V4L2_PIX_FMT_YUYV and/or V4L2_PIX_FMT_MJPEG to
OpenCV now.

> Here is a (very) basic test program which saves 100 frames to disk.

Works OK. Thanks.

Thanks for your help.

        Olivier
-- 
   . __    . ___  __.  | Olivier Bornet         Oli...@id...
  / /  `  / /  / /  /  | IDIAP             http://www.idiap.ch/~bornet/
 / /   / / /--/ /--'   | CP 592        http://www.idiap.ch/~bornet/pgp/
/ /__.' / /  / /       | CH-1920 Martigny           PGP-key: 0xC53D9218