[gst-devel] VIDIOC_S_CTRL with GStreamer

[Clark, Rob]

Note that there is also a device-fd property on v4l2src/v4l2sink that would allow access to the same file descriptor..

On Mar 20, 2010, at 1:50 AM, Yiliang Bao wrote:

> Hi John,
> 
> Yes, you can do this. You can open another file on the same device using following function, even if the device is already streaming video. 
> 
>   fd = open (videoDevName, O_RDWR /* required */ | O_NONBLOCK, 0);
> 
> Usually it is allowed by the v4l2 driver, as long as you are not trying to stream video in the second opened instance.
> 
> Yiliang
> 
> On Fri, Mar 19, 2010 at 8:59 PM, John Buckley <buckleyassoc at comcast.net> wrote:
> Hello,
> I would like to set the V4L2 zoom and focus controls on a compatible camera while using a Gstreamer pipeline to stream video.
> 
> I see the documentation on how to get and set the controls using VIDIOC_G_CTRL & VIDIOC_S_CTRL commands but this assumes that you have opened a connection using v4l2-open and have a file handle to the v4l2 camera.
> 
> Can v4l2 commands to set control values be sent while a Gstreamer pipeline is active?
> 
> - John
>