Gst-launch-1.0 encode failed

i use v4l2-ctl can get images, but i want to use gst-launch-1.0 to encode the /dev/video0 node data, but it can not get image ,how i should do next ??

image

Fist check v4l2-ctl --stream-mmap able to streaming continuously.
Then check if able show the preview like below example command.

gst-launch-1.0 v4l2src device=/dev/video0 ! 'video/x-raw, format=(string)UYVY, width=(int)1920, height=(int)1080,' ! xvimagesink -ev