I think it's stable, but, it's possible that it's Macsbugs compliant. For more information, see the QuickTime Image File Format Specification, which describes the import formats. Movies can be regular movies, QTVR panos, images, animated images, or QuickDraw 3d models. Movies can play. QTVR panos now work.
Images are static.
Animated images can be played. QuickDraw 3d models are static. Note that you might have to wait a while to read in a QuickDraw 3d model. I can wait 30 - 45 secs for a complex model. Movies will be allocated from the System heap as needed by the Movie toolbox.