There's two parts to the implementation. First part is a docker container that will transcode a stream for Janus using the hardware on the Pi:

https://github.com/mmastrac/gst-omx-rpi-docker

I run this with the following config (just remember to map the RPi /dev/vchiq device into the container!):

  gst-launch-1.0 rtspsrc location="rtsp://admin:(password)@(host):554/cam/realmonitor?channel=1&subtype=0" latency=500 ! rtph264depay ! h264parse ! omxh264dec ! omxh264enc target-bitrate=500000 control-rate=1 ! video/x-h264, profile=baseline ! h264parse ! rtph264pay name=pay0 config-interval=1 pt=96 ! udpsink host=(janus) port=8004 sync=false

The second part is the Janus configuration magic that creates the appropriate stream:

  [gstreamer-sample]
  type = rtp
  id = 1
  audio = no
  video = yes
  videoport = 8004
  videopt = 96
  videortpmap = H264/90000
  videofmtp = profile-level-id=42E01F\;packetization-mode=1\;level-asymmetry-allowed=1
  videobufferkf = yes

> I really like your Stylus project btw!

Thanks! Been working on Stylus a bit more this weekend. Nearly have all the features I need for my own setup.