Correlation With MP4
Because both the QuickTime and MP4 container formats can use the same MPEG-4 formats, they are mostly interchangeable in a QuickTime-only environment. MP4, being an international standard, has more support. This is especially true on hardware devices, such as the Sony PSP and various DVD players; on the software side, most DirectShow and Video for Windows codec packs include an MP4 parser, but not one for QTFF.
In QuickTime Pro's MPEG-4 Export dialog, an option called "Passthrough" allows a clean export to MP4 without affecting the audio or video streams. One recent discrepancy ushered in by QuickTime 7 is that the QuickTime file format now supports multichannel audio (used, for example, in the high-definition trailers on Apple's site).
Read more about this topic: Quick Time File Format