A question because I am ignorant about low-level software.

Are there any self-decoding complex file formats?

I remember when you had to download hundreds of different codec packs in order to watch movies.

Given the size of a movie or audio file, would it be possible to bundle it with a cross-platform (Java?) decoder?

@Edent it would basically be an executable with the 'content' embedded in a data section. No different to self-extracting zip file.

There are even techniques to do multi-platform run anywhere binaries, eg: https://github.com/jart/cosmopolitan

GitHub - jart/cosmopolitan: build-once run-anywhere c library

build-once run-anywhere c library. Contribute to jart/cosmopolitan development by creating an account on GitHub.

GitHub