s9roll7

There is no need to install transparent_background separately. It is installed by itself as one of the dependent libraries when you install the extension.

It seems that clipseg was added to transformers 4 months ago. Perhaps the transformers in your environment are too old.

It sounds like an ffmpeg related error. Does the same thing happen with video files picked up randomly from around here and there?

ebsynth utility -> configuration -> etc -> Mask Mode Invert Then execute stage 1