MOV (Apple QuickTime video container)

The QuickTime (.mov) file format functions as a multimedia container file that contains one or more tracks, each of which stores a particular type of data: audio, video, effects, or text (for subtitles, for example). Each track either contains a digitally-encoded media stream (using a specific codec) or a data reference to the media stream located in another file. Tracks are maintained in a hierarchal data structure consisting of objects called atoms. An atom can be a parent to other atoms or it can contain media or edit data, but it cannot do both.

The ability to contain abstract data references for the media data, and the separation of the media data from the media offsets and the track edit lists means that QuickTime is particularly suited for editing, as it is capable of importing and editing in place (without data copying). Other later-developed media container formats such as Microsoft's Advanced Systems Format or the open source Ogg and Matroska containers lack this abstraction, and require all media data to be rewritten after editing.

Other file formats that QuickTime supports natively (to varying degrees) include AIFF, WAV, DV, MP3, and MPEG-1. With additional QuickTime Extensions, it can also support Ogg, ASF, FLV, MKV, DivX Media Format, and others.

QuickTime and MPEG-4

To create an MP4 file, choose MPEG-4 in the Export dialog.On February 11, 1998 the ISO approved the QuickTime file format as the basis of the MPEG-4 Part 14 (.mp4) container standard. By 2000, MPEG-4 Part 14 became an industry standard, first appearing with support in QuickTime 6 in 2002. Accordingly, the MPEG-4 container is designed to capture, edit, archive, and distribute media, unlike the simple file-as-stream approach of MPEG-1 and MPEG-2.

Profile Support

QuickTime 6 added limited support for MPEG-4; specifically encoding and decoding using Simple Profile (SP). Advanced Simple Profile (ASP) features, like B-frames, were unsupported (in contrast with, for example, encoders such as XviD or 3ivx). QuickTime 7 supports the H.264 encoder and decoder.

Container benefits

Use Passthrough to change to the MP4 container without re-encoding the stream.Because both the MOV and MP4 containers can use the same MPEG-4 codecs, they are mostly interchangeable in a QuickTime-only environment. However, 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 / Video for Windows codec packs[9][10] include an MP4 parser, but not one for MOV.

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 MOV file format now supports multichannel audio (used, for example, in the high-definition trailers on Apple's site, while QuickTime's support for audio in the MP4 container is limited to stereo. Therefore multichannel audio must be re-encoded during MP4 export.