How to periodically get the current frame from a streaming video (stream) from Youtube and / or from arbitrary webcams?

Question

YouTube

It is necessary to periodically receive and display the current (last available) frame from the Youtube stream, or from arbitrary video broadcasts. I did not find such a chip in the Youtube API. All that I could find is related to static video, not streaming.
How is streaming video implemented? Where to begin?
I would not like to get into the topic of video decoding very deeply, because the task seems to be simple.
PS Is it really necessary to render a page with a video in some internal Qt browser and take a screenshot? Decode via ffmpeg? (sounds complicated)
These are some terrible crutches, I would like a more adequate solution.

Answer 1

Casperjs go to youtube broadcast, load timeout save player area. Profit.
On Casper, this is approximately 25 lines of code, in mana you will find examples of ass eating