It's understood that Quicktime Player Pro is better, more accurate than the default Qt Player. I have some HD ProRes files I made in FCP from a prosumer camera card that on a client's 2 yr old Mac (default Qt Player) play with bad jaggies.* The footage is fine when I play it on my system in Qt Player Pro. * I can replicate this in OS 10.7.3 with the default Qt Player.
I can tell here things like my set-up is a truer reflection of what is really there and don't worry, but she's freaked and I'd like to offer a more informed, definitive explanation. What would that be?
p.s. I did an edit on site recently where a exported FCP seq (ProRes I *think*) had weird (colorized or blown out) 1st frames after each edit in Quicktime Player Pro but looked fine in the default Qt Player and After Effects. The lesson… Quicktime Player Pro is better, more accurate except when it's not? :-)