ah, such a mix of opencv/qtgui! 

but may be it exposes enough to make it into pure c++ pass?

Still no idea how dynamic metadata work .. there are standarts but they a bit hard to read for me:

Tonemapping using those already supported by ffmpeg's libplacebo filter, but this one need Vulkan driver/device!

And how to *construct* those types of metadata is not clear for me .....