Hi,
Please get support formats:
$ v4l2-ctl -d /dev/video1 --list-formats-ext
and specify it in the pipeline:
$ gst-launch-1.0 v4l2src device=/dev/video1 ! <b>video/x-raw,format=YUY2,width=848,height=480,framerate=30/1</b> ! nvvidconv ! 'video/x-raw(memory:NVMM),format=NV12' ! nvoverlaysink