v4l2 user controls

[Kavalauskas, Matthew (GE Healthcare)]

>> I would like to access v4l2 user controls
>> (http://v4l2spec.bytesex.org/spec-single/v4l2.html#CONTROL) other than 
>> brightness, contrast, saturation, and hue are supported.  Do I need to 
>> add those controls to gstv4l2object.c or is there another way?

> The might be to get the file descriptor from v4l2src using the "fd"
> property and then call ioctls() on that yourself (might need to block some
> pad somewhere to make sure v4l2src is not doing stuff on the fd at the
> same time in the streaming thread).

Thanks for the suggestion Tim.  Let me throw one more wrench into the works.  I need to do this in Java.  (I am using gstreamer-java.)  My understanding is that I will need to write some JNI code to do an ioctl.  If I have to do that, then I might as well instead modify the gstreamer v4l2 code so others can benefit from the work.  I have also looked at v4l4j, but the license prevents me from using that.

So, is there an existing pathway in gstreamer that allows me to access any ioctl?  Or (probably outside the scope of this mailing list) is there any Java/JNI code that lets me access any ioctl?  After thinking about it, I think the answer is no for both questions, but I would be happy to hear a confirmation or correction.

Thanks again.
Matt