Specifically, Apple's "MPEG-4 Video" codec for QT6 is just MPEG-4.. QT6 itself still supports all the other stuff it used to. The standard MP4 container for MPEG-4 media is essentially a subset of the QuickTime MooV container.

If you install 3ivx it includes a MOV parser (and AAC decoder, too) that works to let you play .movs in any DirectShow app without QuickTime, if you have appropriate codecs for the video of course. 3ivx plays almost anything vaguely related to MPEG-4 except MS-[airquote]MPEG4[/airquote] v1 and v2. Plus it's the fastest decoder available (at least for OS X, not entirely sure that applies to Windows) and has the best postfiltering capabilities.