gst-launch-1.0 -e \
videomixer name=mix \
    sink_0::xpos=0   sink_0::ypos=0 \
    sink_1::xpos=480   sink_1::ypos=0 \
    sink_2::xpos=0   sink_2::ypos=270 \
    sink_3::xpos=480   sink_3::ypos=270 \
rtspsrc location=rtsp://192.168.10.3:554/ user-id=admin user-pw=Babl\!@#456 latency=150 \
! decodebin max-size-time=30000000000 \
! videoconvert ! videoscale \
! video/x-raw,width=480,height=270 \
! mix.sink_0 \
rtspsrc location=rtsp://192.168.10.2:554/ user-id=admin user-pw=Babl\!@#456 latency=150 \
! decodebin max-size-time=30000000000 \
! videoconvert ! videoscale \
! video/x-raw,width=480,height=270 \
! mix.sink_1 \
rtspsrc location=rtsp://192.168.10.4:554/ user-id=admin user-pw=Babl\!@#456 latency=150 \
! decodebin max-size-time=30000000000 \
! videoconvert ! videoscale \
! video/x-raw,width=480,height=270 \
! mix.sink_2 \
rtspsrc location=rtsp://192.168.10.6:554/ user-id=admin user-pw=Babl\!@#456 latency=150 \
! decodebin max-size-time=30000000000 \
! videoconvert ! videoscale \
! video/x-raw,width=480,height=270 \
! mix.sink_3 \
mix. ! queue ! videoconvert ! v4l2sink device=/dev/video2 sync=false