Chroma Key turns anything not behind it black

Bug
,
1

  • What is your operating system?

Windows 11

  • What is your Shotcut version (see Help > About Shotcut)?

I just updated to 25.08, I believe

  • Can you repeat the problem? If so, what are the steps?

Step 1: Add at least 2 video sources, one of them in need of Chroma Key

Step 2: Apply Chroma Key

Step 3: Profit(?)

  • Workaround

I applied a Size, Position & Rotate filter to the source with Chroma Key and it’s working properly again. I fell like reporting this bug is still a good idea, though. Please let me know if there’s any kind of log file I can share for this!

Images

With Chroma Key Active

image
image357×163 36 KB

Without Chroma Key Active

image
image275×247 39.2 KB

2

Unable to reproduce and unclear. Your screenshot does not clarify the problem as the background below the explosion is not black and “anything not behind it” would be what? The explosion? That is not black either.

3

I think the problem here is the green clip not being the same ratio as the project.
When the Chroma Key filter is applied, we can see black bars on the top and the bottom.
Adding a SP&R filter removes the black bars.

4

I see. I think most of the time you want to use a Size, Position & Rotate with this anyways. Chroma Key: Advanced with Operation = Minimum is another workaround if you really don’t want SPR. Or add a Crop: Rectangle with Padding color = Transparent to crop out the black bars.

5

oh dang that’s kinda weird, Thank you for sharing it!

6

This is fixed for the next version 25.12. Also, I changed the Chroma Key: Advanced filter’s Operation to default to Minimum.