HDMI exractor, HDMI Audio Splitter Adapter: no picture

There is an HDMI connector into which the HDMI ports go, including the box (x96 max+)
Something must be set under CE, otherwise there is no picture when I start playback. There is an option to add the resolutions to a list (even all the available ones), but even then it doesn’t display movies… their resolution is not currently known, but it worked a long time ago when I added a few resolutions here, e.g. 4K, 1080p, 720p…
What can be a solution?

Most likely your Splitter isn’t connected to a TV, or doesn’t bypass the EDID from TV.
In this case try coreelec:video_disp_cap [CoreELEC Wiki]