Can a linux distribution provide an API to a proprietary codec? If so under what conditions?

As an example lets take the MPEG2 codec, let us say I am building a Linux distribution which I intend to ship in two pieces.

Piece 1: (free) Core libraries and applications

Piece 2: (paid) Proprietary applications and libraries I create.

Now say I permit 3rd party developers to call video decoding for my linux distribution. Which of the following configurations are legal? Do the licensing fees vary if I bundle with a similar application vs entire system? If Illegal please cite why.

1. MPEG-2 is not shipped as part of free variant, but an OS component asks to download it if it is required. Does this mean my software behaving illegally, or the end-user is using the software for "personal use".


2. MPEG-2 is shipped as part of the paid component and I pay MPEG-LA, I still provide an API for video decoding to 3rd party developers.


3. The software is not shipped as part of the OS, but I provide a paid codec package, pay MPEG-LA, and then provide 3rd party developers a video decoding API.