Extracting selected images from downloaded video files?

I want to extract selected images from downloaded video files. I’d like to know whether Membrane is a reasonable tool for this job, whether anyone else has done similar tasks with it, etc. I’m also unsure about how its “pipeline” approach would fit a “random access” use case.

For purposes of discussion, assume that I’ll be using VLC media player to download videos from web sites such as YouTube, storing them as MP4 files. Because I’ll be processing the images, I’d like to get them into Nx tensor format.

Can someone give me some advice, clues, and/or suggestions?