I post this here as the last time there was a codec overhaul, massive problems occurred with Avid Unity and QT Reference file encoding.

And it was thus said by Avid:

The QuickTime codecs v2.2.1 addresses an issue encountered in Avid Media Composer v4.0.5, Avid Symphony v4.0.5, and Avid NewsCutter v8.0.5 in which DVCPro, MPEG, and Avid DV exports result in black video. See KB Article 350631 for additional information regarding this issue. Mac and PC versions of the installers can be downloaded below. For more information about these codecs visit the Avid QuickTime Codecs LE 2.2.1 Specifications page. For complete install instructions, reference the ReadMe file below.

Avid Codecs LE v2.2.1 ReadMe
Avid Codecs LE v2.2.1 Installer Mac
Avid Codecs LE v2.2.1 Installer PC