4K video files result into white video after rendering
I have read about similar issues, they were mostly linked to file names with spaces or proxy files. Both does not apply in my case. When I use a 4k video with 50 fps I get a white preview. Enabling proxy does show and allow to edit/cut the video, but as soon as I render it is white again. Converting those same videos to 1920x1080 with ffmpeg and it all works fine.
It seems kdenlive can read/use the 4K files though, as it generates the proxy files without problems.