It's XORed with a stream cipher, so it's totally secure (no part of the stream is reused).

The tricky bit might be deciding where to start the stream...

If the static image could be somehow "bankswitched", "shifted" or updated... I am thinking a huge one time pad. The problem is doing it power effeciently of course.

Thinking about, the main problem will be the penguin problem [1]. Which for a video is even worse as if a shape is moving, from seeing the pixels that are changing you can tell most of what is going on.

[1] https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation...

In my mind, strong encryption that can fend off the most serious attackers cannot apply to the analog part of the application.

However, analog scrambling techniques should still be effective in many cases.