Q on DMABUF: how to get fd info from downstream plugin

[Makoto Harada]

Dear gstreamer expert,

I'm now working to implement DMABUF feature to our custom video encoder plugin,
which would be directory connected to v4l2src in the gstreamer pipeline. (We
have already validated the DMABUF functionality of our kernel by using some
simple V4L2 applications, so now the turn of gstreamer)

I've checked the DMABUF related commits of git repository including two commits
below, and also checked the discussion regarding DMABUF on this mailing list.
https://bugzilla.gnome.org/show_bug.cgi?id=693826
http://lists.freedesktop.org/archives/gstreamer-commits/2013-February/069408.html

On top of that, I have two questions.

1. How the information of file descriptor of DMABUF memory, which is allocated
by VIDIOC_EXPBUF ioctl, is expected to transfer to the downstream element, and how 
the downstream element is expected to receive it ? I've checked gstdmabuf.c and 
gstdmabuf.h in gst-plugins-base, however could not find such kind of information.

2. Does anyone know if there is any working gstreamer plugin which acts as the 
DMABUF importer, and works with v4l2src ?

I'm newbie of gstreamer world, so any kinds of information would be helpful.

Kind Regards,
Makoto