OS 10.5.8
I have just downloaded DivX Plus 9 and it goes on to advise that I remove several obsolete QT components as well as perian due to it's approaching demise.
Question; will perian serve any purpose if I keep it, or should I uninstall it?
Digressing for a moment, can someone tell me where I can find DivX's codec pack?
jaybass

Perian for QuickTime will no longer be maintained and updated, in part because (QuickTime) alternatives are available for current OS versions. However, those alternatives may not be available for Leopard, and consequently, as long as you use that, removing Perian may not be a good idea unless an alternative like DIVX Plus can take over. Note that the Perian site also lists alternative players.

If you consider switching players, make sure your choice of player or codec pack can handle the file formats and video types you want to view in an acceptable way. Both Perian and DivX sites (scroll down) list the ones they handle. Note that DivX handles fewer than QuickTime w/ Perian, but handling of some formats/types may be faster (e.g., .mkv). Also note that DivX player 9 may have updated codecs for one or some formats (likely DivX itself), but not necessarily for others it handles, and certainly not for those it can't handle. I also can't tell if DivX Player 9 will interfere with QuickTime/Perian playback or vv, so you might want to keep that possibility in mind if you pick DivX but don't want to remove Perian right away.

PS, the DivX Player includes several codecs; I don't believe their codec pack adds anything to that (see the format/feature chart mentioned above), at least not this one. If anyone feels the need to correct this view, please do, with available details.

DivX Plus HD MKV, H.264, AAC/MP3/AC3. Plus creates files up to 1920x1080 and also avi's. Perian does suggest another player... something like niceplayer? but I have 3 others so I don't need it. The interface of version 9 is much better than the previous one with a drop down menu showing the above. Also the conversion speed is much faster. I converted 2 this morning.
I have just taken time out to play a QT movie in the DivX player with no problem.
I am very pleased with 9 but I will leave perian installed for now. I don't anticipate anything untoward with leopard but if I do, I will let you know.
Thanks for the reply, jaybass