The presence of unneeded codecs, 3ivX in particular will exhibit this symptom. Perian 1.0 is about all one needs now plus Flip4mac for Windows Media. See if you have that or old DivX etc.
after a fresh reinstall from zero this morning on my external hard drive (to test where is the problem), only perian installed, the freeze always come after 40seconds...
the only similar point is the machine: iMac G4
I also have an iMac G4 800mhz - seems to be common denominator here.
Hopefully apple will fix this bug ASAP.
I never had any probs whatsoever before I downloaded QT 7.1.6 - all video content played fine. And this problem is only with QT - I have no probs with other media players such as VCL.
putting my G4 to sleep doesn't fix the problem, unfortunately.
I also followed BabyBoomer's advice and repaired disk permissions in disk utility - and while my mac is now running a bit faster, the QT problem still occurs (though video seems to now be playing a little longer before it freezes). .mv4 files seem to freeze much sooner than mpg files, perhaps more a problem with that codec?
Having the EXACT same problem with my G4 iMac.
Video freezes after a few seconds, audio continues.
I even performed an 'archive and reinstall' hoping it would clear this up. After running the usual software updates, the problem persists. I didn't test during the update process to see WHERE in the updates it started going wrong again, and I'd hate to do another reinstall while the first one is still being sorted out.
Happens in both QT and in iMovie as well! Obviously impossible to edit video! Is QT the playback engine for iMovie?
Though I've noticed that if a video file is opened in AOL, the vid plays fine. The bundled AOL software must have it's own version of QT stashed away in there.
i've just downloaded QT 7.2 and the problem seems to have been fixed - no freezing video content after playing three music clips (same clips I had probs with QT 7.1.6) 🙂