[CodeArtisan]

Avisynth+ does that. It is well supported and has a huge community.

http://avisynth.nl/index.php/Main_Page

[zersiax]

I'll check that out :) I'd be curious how well this would work without being able to see the video you're messing with (fully blind myself). Will give that a whirl.

[LeifAndersen]

Author of videolang:

Avisynth+ is awesome.

Interestingly enough, the first version of video was actually built on top of libmlt: https://www.mltframework.org/

I was just dissatisfied with it due to its lack of functions. I can't remember why I didn't just use avisynth as it does actually have functions.

[EvanAnderson]

Definitely going to check that out. Thank you for the link.

[noiv]

AviSynth also has a 'function' keyword.