V4L-2 support in FreeBSD
Hans Petter Selasky
hselasky at c2i.net
Mon Sep 29 07:50:19 UTC 2008
On Monday 29 September 2008, Fritz Katz wrote:
> --- On Tue, 9/23/08, Hans Petter Selasky <hselasky(at)c2i(dot)net> wrote:
> > Hi,
> > Maybe you will find the following file useful:
> > http://perforce.freebsd.org/fileLogView.cgi?FSPC=//depot/projects/usb/src
> Thanks!, Yes, very useful.
> Can you point me at any drivers or user applications
> that include and use this file?
There is an example USB webcam driver in my SVN repository that uses this
file. Just search for webcam: find . -name "*webcam*"
> Are there any plans to check it into the
> tree for FreeBSD-8?
No, not yet.
> Some nits:
> 1) V4L2 has divided the info contained in this file
> into two: videodev.h which contains the obsolete V4L1
> definitions & videodev2.h
> when I attempt to link a V4L2 application using it,
> I get compiler errors and am forced to edit the source
> files to get them to compile.
> Without V4L-1 structs and ioctl definitions, many
> older applications won't compile.
The V4L-1 part has been stripped away. It is a pure V4L-2 library. I have
compiled with ekiga and was able to use my webcam, although some work remains
like moving the decoding of the JPEG frames from a kernel thread to a
> 2) The "#define V4L2_STD_PAL_NC" is "#define V4L2_STD_PAL_Nc"
> in V4L2. (Just because Penguins do something silly like
> putting a lower case letter in a define doesn't mean we
> should do it too -- but it *IS* their standard).
Just send me a patch.
> > Regarding porting, there is not much you need to do. Simply
> > make sure that you handle the IOCTLs directly in the video driver.
> > --HPS
> Yes, "piece of cake!" :-)
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