Warning about ffmpeg

At the end of the App ProRes White Paper released earlier this morn there's an explicit warning about using ffmpeg:

In some instances, unauthorized codec implementations have been used in third-party software and hardware products. Using any unauthorized implementation (like the FFmpeg and derivative implementations) may lead to decoding errors, performance degradation, incompatibility, and instability.

This means Perian and other software that might use ffmpeg in some form. Clearly it's not working with the current OS and causing problems with AV Foundation, which QuickTime and FCP rely on.