Do cats and dogs really understand movies?

It is a surprise to me that cats or dogs can recognise anything on tv at all, as they have to understand that a 2D image represents 3D things, but this video is evidence that they do:

Funny Cat Watching TV
https://www.youtube.com/watch?v=U6PXDdwhhqM

My question is, do they really understand the drama and story in movies as the two following videos suggest? Or are they fakes?

Cat Watching Horror Movie
https://www.youtube.com/watch?v=_kgRFHaNo-Y

Bulldog watches a horror movie, does something INCREDIBLE during scary scene
https://www.youtube.com/watch?v=uffjKmTBjTI

I imagine that cats and dogs only saw old CRT tvs as a lot of flickering.