device is not an output device - using vivid with gstreamer

Hello,
I am trying to use gstreamer with vivid .
the idea is to use vivid to  simulate 4 virtual cameras.
Then, use gstreamer to write images to these virtual cameras.
when i try writing to the device using gstreamer,i get the following error
"device '/dev/video3' is not a output device".
I was using the following link  to ensure that the devices are set as
output devices:
https://www.kernel.org/doc/html/v4.14/media/v4l-drivers/vivid.html
details below.
I will appriviate any advise.
Thanks !

1.  sudo modprobe -r vivid
2.  sudo modprobe vivid num_outputs=4 output_types=0x00
3. v4l2-ctl --list-devices
    result:
    vivid (platform:vivid-000):
   /dev/video3
   /dev/video4
   /dev/video5
   /dev/video6
   /dev/radio0
  /dev/radio1
  /dev/vbi0
  /dev/vbi1
  /dev/swradio0
  /dev/v4l-touch0
  /dev/media1
4.
 gst-launch-1.0 -v multifilesrc location=./%05d.png loop=1
caps="image/png,framerate=30/1" ! pngdec ! videoconvert !
"video/x-raw,format=YUY2" ! v4l2sink device=/dev/video3
return error:
ERROR: from element /GstPipeline:pipeline0/GstV4l2Sink:v4l2sink0: Device
'/dev/video3' is not a output device.
Additional debug info:
../sys/v4l2/v4l2_calls.c(636): gst_v4l2_open ():
/GstPipeline:pipeline0/GstV4l2Sink:v4l2sink0:
Capabilities: 0x5230005
ERROR: pipeline doesn't want to preroll.
Failed to set pipeline to PAUSED.

5. same for video4,5,6