If you
want to learn about the physics of electron scanning, it probably won't hurt. :) But the basics shouldn't be too complex. I can only give you general details, hopefully someone else visits this thread with more specifics.
For video, all you're doing is reading an image from disk, decoding (decrypting) it, displaying it somehow (send it to a display buffer? Have a window drawer draw it?), and then starting with the next image in the stream. There's some timings, and reuse of data from the previous image, but it can all be done programmatically.
I'm more fuzzy about audio, but I believe you're basically loading audio data from disk, decoding it, then output to an audio buffer that does the DAC etc for you. Timings again, but still nothing that's not programmatic.