how to use gstreamer plugin glvideomixer

I need merge four images, and find glvideomixer can do ti.But how to use it correctly?

Now i create pipelin :

gst-launch-1.0 glvideomixer name=m sink_0::xpos=0 sink_1::xpos=320 ! glimagesink  videotestsrc ! m.  videotestsrc pattern=1 ! m.

but it doesn’t work. Can someone give me a right examples?

hi wuyindong,
glvideomixer is not an NVIDIA-developed plugin. Please refer to the public doc: