XiphQT

Xiph QuickTime Components (XiphQT) is a 32-bit plug-in for QuickTime which provides access to any of the codecs and formats supported by the Xiph.Org open source community. This means any QuickTime-based application would be able to open and read these formats through this plug-in. Similar downloads are available for Windows and Linux.

Discontinuation
The last release of XiphQT for Mac OS X was version 0.1.9 on June 14, 2009. On June 13, 2016, it was announced that development had been halted due to the deprecation of QuickTime 7 and the lack of an access to an API like QTKit for QuickTime X.