First frame shown twice and last frame missing

Hello everybody,

I just discovered a strange issue with QuickTime 7.7.6 on a Windows 7 SP1 64-bit Workstation (HP Z800). An MP4-videoclip that was transcoded using a mainconcept codec is not played back properly within QuickTime on Windows. The first frame is shown twice and the last frame is missing.

If I play the same videoclip on a Mac it is shown correctly, so I don't think that there is a problem with the clip itself. The behavior was discovered when this clip has been AMA-linked into the Avid Media Composer.

I already tried QuickTime 7.7.5, but there is the same behavior. Any ideas why this happens?

Best,

Sebastian