Have you upgraded to the Mountain Lion OSX 10.8? Do you recognize that the "Playback" of Perian can’t be detected, when you finish the upgrading job? The Perian always has nice compatibility with old versions like Snow Leopard, Leopard, etc. Thanks to the a simple and straightforward Perian plug-in, the QuickTime becomes more capable, more file formats supported like AVI, FLV, MKV and DivX.
Will the Perian run on Mountain Lion in the future? No. Early in this May, the Perian development project had announced it would no longer be making future versions of the plug-in.
In the case, how to playback your source files like AVI or FLV with QuickTime comes to be a common problem. Anyway, here is a workaround solution, which enables you to watch almost any movie file with QuickTime by converting video to QuickTime natively file format like MOV, MPEG-4, then seamlessly watch the output movies with QuickTime player.
Doremisoft Video Converter for Mac can easily convert almost any video or audio to your target formats like MOV, MP4, MKV, etc. Plus, it has rich presets for media players like QuickTime, iTunes or hot video editing programs like iMovie, Final Cut Pro and so forth.
Click "Add File" to the program, such as .avi file. In addition, you can add multiple files at one time.
Directly select the "QuickTime Player", then you will get the .mov file, which is natively supported by the player. Also, you can choose iMovie->iMovie MPEG-4 as output file format, if you would like to edit the video like MTS in iMovie. Its presets for handy devices are provided for those who intend to enjoy movies on the move.
Hit the "START" button to do the conversion. When the conversion is done, you can directly access to the generated file(s) by default.