Background tracks video disappears, during a video transition

[Riven]

I’m aware this bug has been around for some time and the fix I used for it is to add a default rotate and scale filter to the transition itself, which then shows the background layer. However, I just want it tracked for a fix at some point.

Steps to reproduce:

1. Create two tracks
2. On the bottom track add a still background image full screen e.g 16:9
3. On the top track have two clips and add a transition that are a smaller size, say two 4:3 clips

On player back, the background layer will disappear during the transition even in the areas the video track doesn’t display.

Example footage of issue:

Known work around add a rotate and scale filter to the transition, to display the background layer. Test in Shotcut version 19.04.30 (Latest as of writing)

[qubodup]

The issue can be seen at 0:18

I suggest the following workaround as long as the bug persists: don’t place the frame decoration on a background track, instead place them on the foreground track. You might have to convert the image used to PNG and make the middle transparent in for example GIMP

[Riven]

Yes, that work around would be a bit cleaner than my one, as you wouldn’t need to add scale and rotate to every transition as I do.

[sauron]

Another possible workaround is to add an alpha channel adjust to the clips before creating a transition.

https://streamable.com/8npvq