Scrypted FFmpeg Input Stream Arguments

Did you get this working?
I'm in the same place as you.

All other methods of getting the OctoPrint camera into HomeKit suck, poor quality and/or laggy.

No. I couldn't figure out the right things to put in for the stream URL.

I was able to get an OctoPrint stream into Scrypted ffmpeg using the OctoPrint plugin "Camera Streamer Control" (I was using this for a webrtc stream at one point):

ffmpeg input stream: -i http://OCTOPRINTIP/webcam/video.mp4 (I'm not using any additional settings for the stream, but I assume the Scrypted ffmpeg plugin will work with those).

snapshot url: http://OCTOPRINTIP/webcam/snapshot

To be transparent, this is part of the new camera-streamer webcam stack discussed in A new camera stack for OctoPi

Ah yes, thanks for the clarification/correction. I did switch to the new camera-streamer webcam stack a little after that blog post (and apparently forgot that this plugin was part of that, rather than something I downloaded after the fact).

The webrtc stream would also be available to scrypted I suspect without the plugin. The plugin just makes the webrtc implementation of camera-streamer work within OctoPrint.