The facts: I recorded my HDR videos from games and edit it without previewing or adjusting color. I just do very simple cuts and voice over.
The result: fine for exporting the game videos themselfs. They maintained the same color space and looked fine in video players.
BUT!
I met the problem when I tried to add an image layer above the HDR video track because I wanted to indicated something in the game and provide extra info to viewers.
When exporting, this image layer went wrong in poor color display; they looked like with wrong Gamma and has bad color tuned (“a broken dark-red”).
These images are either jpg or png, in RGB. They looked fine in SDR videos.
I think I should change some line in there but don’t know which and how.
It looks like this one?
mlt_image_format=yuv444p10
OR, should I do something with those images in Photoshop?
Basically, SDR or sRGB in a HLG HDR project does not really work yet. But you can hack it in by doing various color adjustments. You need to figure out what works for you in that regard. There is no simple single setting or change somewhere. That is why preview in HDR is important, but only through Blackmagic Design peripherals at the moment. For those reasons, I do not claim Shotcut supports HDR (not announced, not on Features page).
I think your answer inspired me, now I solved the problem by modified my images in Photoshop, converting them from RGB8 to RGB32 (with a PQ profile).
Then this worked for me.
Like I said, my input videos and output videos were quite fine in PQ. The only problem was the image layer, which I used to drag RGB8 jpegs directly without any pre-processing.
