I have Perian and Flip4Mac Pro installd and current.
Videos encoded "wmv3": Video o.k., sound only for a few tenths of a second, then silent.
Videos encoded "wmv2": Video o.k., no sound at all.
Videos encoded "DivX 5.0": Does not play at all.
Videos encoded "Generic MPEG-4" don't play at all
Videos encoded "DX50": Don't play at all
Videos encoded "xvid": Don't play at all
They play perfectly in QuickTime 7, VLC and others!
Any help appreciated!
To put it plainly, QT X does not have the same open architecture that QT 7 enjoys. In some instances, many third-party codec components (especially those handling legacy video compression and non-native audio formats) are not supported in QT X and require you to fall back to the use of QT 7 or QT 7 compatible apps like MPEG Streamclip. In other instances, QT X will not even look for a supported codec component if the data is stored in certain file containers. (E.g., QT v10.1 normally plays "muxed" MPEG-2 video with AC3 audio in an MPEG or TS file container but will ignore the same content in a VOB file container.)
I found all my problems started with the auto update of perian removed all codecs from quicktime library uninstalled perian etc. Downloaded perian 1.2.2 installed rebooted and it all works perfectly again also turned off the auto update 1.2.3 has issues with lion and this translated through to all other programs VLC etc.
Hope this helps