I USED to use QTPro to re-export a wide variety of files to .movs so I could use them in FCP. but now StreamClip is my PREFERRED app.
There are so many kinds of file types, created by so many applications, Mac and WIN... but it seems that re-exporting them as new .movs really helps make FCP happy.
I got some QT files made on WIN from another Producer the other day. I didn't think to re-export them as new .movs, I just dragged them into FCP.
FCP sort of liked them (although the audio required render for playback)... DSP4 liked them... but when I put the finished burned DVD in the SONY desktop DVD player, the audio sounded like I had a broken speaker wire while driving on a gravel road. I burned a 2nd disc, and I got a "Can't play this disc, disc might be "dirty" " error.
So I put the DVD in the G5 internal DVD drive, and after waiting 2 mins for it to mount on the desktop, I used every trick I could think of to eject the disc. Finally, I have to remove the drive from the G5 and put it in an external enclosure, hook up JUST the power cable, and it finally ejected!
So I went back to FCP, deleted the audio tracks, re-exported the origs from StreamClip, and all is now well.
Independent photographer, film maker and Producer. In the wonderful UK.