Works great and is very useful with Leopard.

On Snow Leopard, it seems to have lots of problems as reported in Perian support forum. Most troubling, the forum moderator locked the thread reporting Snow Leopard problems. They do not appear interested in fixing the problems and do not want to hear about them.

Problems in Snow Leopard include:
- Some video types will play with audio but no video
- Some video types will play but very poorly with jumpy video, possibly slow framerate.
- Integration with Frontrow in particular has issues.
- Some video file types cannot be handled directly by QuickTime10. Additional programs are needed as a bridge so that they can handle the file type and pass it to Quicktime with Perian to play.

The end result is that Perian is currently much less useful on Snow Leopard until or if they can fix these problems. Hard to see how anything will be fixed if they don't want to hear about the issues.

I do not know if installing Quicktime 7 solves any of these issues.

Dead link