Can't get IP-Camera (Tapo C200) to work, although its thing is online

I installed the IP-camera-binding and installed a Tapo C200 which is supposed to support onvif. After some struggling, I managed to create the thing and it’s shown as online (settings: 1st screenshot). Then I added items for all channels that were available. However only very few of them show something other than NULL (2nd screenshot). At least RTSP URL shows the correct address. I know it’s correct because I it works with VLC where the stream is shown.
However, when I try to use this address or the item in a ‘video card’, no stream is shown (3rd screenshot).
My questions:

  • How to get the stream working?
  • Can I get the other items filled with data too? Or are they not supported by my camera and the channels/items are shown for every camera anyway, no matter if they support them or not?
  • What are the FFMPEG-settings good for? If they’re of any use, what should I enter there? (4th screenshot shows FFMPEG settings from iSpy, but I haven’t changed them yet)

The problem was that I hadn’t installed ffmpeg. For others with similar problems: