BitComet Support Team's BLOG

QuickTime is a multimedia framework developed by Apple Inc. capable of handling various formats of digital video, media clips, sound, text, animation, music, and several types of interactive panoramic images. Available for Classic Mac OS, Mac OS X and Microsoft Windows operating systems, it provides essential support for software packages including iTunes, QuickTime Player (which can also serve as a helper application for web browsers to play media files that might otherwise fail to open) and Safari.

You can use mpcstar to open files with this suffix. http://www.mpcstar.com/