Subtractive mask issue (newbie)

[Hudson555x]

I’m not sure it’s documented anywhere. V1 has to be on for compositing.
It was a change a few years ago to Shotcut.

It’s been mentioned a few times in the forum on the use of V1.

Fade In and Fade Out filters. Adjust opacity instead of fade with black

This will not work with the primary use case of fading on V1 because V1 is not blended with the hidden black background as a performance optimization. If it did do blending, then it completely makes sense to remove the option and simply fade the opacity. However, the video processing performance is already an issue for most people in general such that I have not changed this model. If the performance improves significantly in the future then I will change this.

Compositing functions counter-intuitive - please enlighten me

In addition to what I already wrote, every track blends/composites with V1 - not V5 to V4, then V4 to V3, then V3 to V2, etc. If you want to know more you need to read the source code. I could make every video track blend with a hidden black background track, but then there will be less performance with a single video track even if there is no transparency. In some cases where images and filters result in RGBA, there is a check to see if there is any non-opaque pixel before taking the performanc…