I found guides that seemed to indicate this should work fine inside octoprint, but when I put in the stream URL the test window shows a broken image link and says it isn't working, but the snapshot test works fine.
If I right-click on that broken image link in the browser and say open in a new tab it opens up http://ip:8080/video which works fine and shows me the video feed.
I don't understand why it isn't working in octoprint and I'm not sure where else to look to debug. I did open a shell inside the docker container and I can access the webcam from there (at least ping/netcat to it).
Not sure what else to test. The longer term plan is to put a USB webcam on it, but I thought I would try to use what I have first but it has been a little frustrating because of this little bump in the road.
I installed OctoCam instead, and stream works, but now I can't figure out how to get the snapshot to work. Looking for the right URL format... [add /?snapshot to the URL]
I tried the ?snapshot on the end of the URL for OctoCam, and it works in a browser but not in Octoprint. Go figure, so it is working exactly the opposite of the IP Camera for me. LoL
I added this plugin Webcam Iframe and finally I could view my video in the control tab. Test button not working but I'm happy with seeing it in the control tab.