[Tod Hopkins] ” Apple has simply decided they don’t want to do this work anymore, but they are not stopping others from doing it.”
AFAIK, a lot of the codecs they are “retiring” were never written by Apple, thus that work was never on Apple. What they are actually doing is not allowing THIRD party codecs to be installed via AVFramework without their approval (no approval has been given to anyone AFAIK). Writing the code for your codec only satisfies specific applications you have control over. The previous QT platform allowed you to write a codec for the QT engine itself allowing any software to access the same codec.