I’ve read a several posts about black backgrounds occurring with image overlays and they usually recommend adding a chroma key filter or setting blend mode, I didn’t achieve any success with either.
My situation is that I’ve added a png logo image to video track V2 with a size and position filter, and V2 is above V1 which contains several clips. Where a clip in V1 includes a simple shape mask (using operation: overwrite) with blur filter to blur a small area, all looks good. Where a second simple shape mask exists (using Operation: Add) the video area outside the masks and logo are black.
So it works ok with one mask but turns black when using more than one mask. Is there any solution to using several masks with image overlay without the black background please?
UPDATE: I think I’ve fixed it! I’ve added the chroma key filter to the video clip V1 track instead of the image V2 track, with the key colour set to the default green; I don’t know why green works and eg white doesn’t.