"Problem adding effect to clip"

[amindfv at mailbox.org]

I'm using an older version of Kdenlive (18.12.3 - the version on Debian Stable). When I try to add certain transitions (the Movit transitions), it gives me an error: "Problem adding effect to clip." Is there any way to work around this?

Hopefully this is fixed in later versions, but even if it is, I'd love to hear of a workaround for my current setup.

Other symptoms:

  - Movit effects (as opposed to transitions) work just fine
  - I've just gone through and tested, and all Movit transitions have this problem, and no non-Movit transition has this problem
  - Kdenlive under the hood appears to successfully use the "Overlay (GLSL)" transition to mix video tracks when I look in the MLT XML, but I'm unable to use that transition myself in the UI

Thanks,
Tom