[MacDV] Why is "MPEG-2 Playback Component" needed?

[Aaron]

I keep on coming across references to the "MPEG-2 Playback Component" and to the necessity to buy it from Apple to be able to do various things with MPEG-2 files even in non-Apple programs.

Is Apple's product the only thing that can do what it does?

If so, is it because it's too difficult to replicate the functionality or is there some kind of legal obstacle to doing so?

What is the exact name and location of the component when installed?

I have old versions of both DVD Studio Pro (1.5) and FCP (3.0), but I can't locate the installers right now. If I can find them, would they have the component?

 - Aaron