Playing ogg files in QuickTime (iTunes)
Xiph QuickTime Components (XiphQT) is, in short, the solution for Mac and Windows users who want to use Xiph formats in any QuickTime-based application, e.g. playing Ogg Vorbis in iTunes or producing Ogg Theora with iMovie.
link: http://xiph.org/quicktime/download.html
Open Source Mac - Free, Open-Source software for OS X
Overview of the best open source software for Mac OS X.
link: http://www.opensourcemac.org/
tags: open source video utilities mac os x audio graphics free software
Perian - The swiss-army knife of QuickTime® components
Perian is a free, open source, QuickTime component that supports many popular media types, including AVI, DivX, and XviD. Also .srt subtitles and e.g. playing .flv in QuickTime Player
link: http://perian.org/
tags: open source subtitles flash mp3 quicktime plugin divx xvid flv avi ms-mpeg sorenson truemotion h.264 mpeg4 aac ac3 audio vbr srt