It sounds like you did never actually installed the MPEG-2 codec. Did you download and install the Perian codec suite?
I wondered about that. The
Snow Leopard upgrade ruined/removed my
QuickTime 7.6.X. The USELESS new
QuickTime would not play video that required the Mpeg-2. Not a "big deal" but I like to edit snippets of video.
After complaining to
--since I had the "Pro" of
QuickTime--reason to save your receipts . . . and downloads--I received fresh copies. Long, long story short, I had to forcibly reload my
QT Pro 7.6--eventually updated to
7.6.6 . . . since the updater kept saying "You have QT X! You should be happy! Why are you not happy? Are you . . . 'Unmutual?!!'"--with the shareware
Pacifist. Same with the mpeg-2 codec. I used the shareware
Pacifist to "force in" the updates and the codec.
That was just after the release of
SL . . . no problems since.
Using Google-Fu [Tm.--Ed.] it appears that
Lion does not come with
QT 7.6.6. So one will need to obtain that. It
may require a Pro upgrade--this I do not know since I upgraded mine WAAAAAAAY back in the days of OS 9!
Apple claims you do not need
QT 7.6.6 OR the
mpeg-2 because of
QTX, but that is not my experience. AND after talking with Apple Support on it, the Twinkie admitted that it was strange if you did not "need it" why would they keep selling it . . . only to eventually murmur that, "yeah, you might actually need it." One of those "but most customers do not!"
Still more searching brought some interesting information from a free "Stream Clip" site:
Squared5
Their discussion of
SL is
exactly what happened when I upgraded--
SL over-wrote my mpeg-2.
I do not have that product, so I cannot comment on whether or not it will help but in searches a few users suggested it. I would suggest, as always, clone your drive, then boot off you clone, then try it. "Mess with clones!" I always say! It is not like they are real humans, even if they are played by Keira Knightley [Get on with it!--Ed.] Right, if it does not work on your clone, you have not lost anything but time . . . which is, of course, a different movie.
Hope some of this helps!
Another reason I have not upgraded to
Lion
--J.D.