Gstream and camera

I RUN THIS COMMAND ON MY RPI3
raspivid -t 0 -h 720 -w 1280 -fps 30 -hf -b 2000000 -o - | gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-h264,width=1280,height=720,framerate=30/1 ! h264parse ! rtph264pay ! udpsink host=192.168.100.247 port=5600
and i get error
Setting pipeline to PAUSED …
Pipeline is live and does not need PREROLL …
Setting pipeline to PLAYING …
New clock: GstSystemClock
ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Internal data stream error.
Additional debug info:
gstbasesrc.c(2950): gst_base_src_loop (): /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
streaming stopped, reason not-negotiated (-4)
Execution ended after 0:00:02.684326666
Setting pipeline to PAUSED …
Setting pipeline to READY …
Setting pipeline to NULL …
Freeing pipeline …