QuickTime File Format

Design

The format specifies a multimedia container file that contains one or more tracks, each of which stores a particular type of data: audio, video, or text (e.g. for subtitles). Each track either contains a digitally-encoded media stream (using a specific format) or a data reference to the media stream located in another file. Tracks are maintained in a hierarchical 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 is not supposed to 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 Matroska and Ogg containers lack this abstraction, and require all media data to be rewritten after editing.

Relation to 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 PlayStation Portable 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 discrepancy ushered in by QuickTime 7 released on April 29, 2005, is that the QuickTime file format supports multichannel audio (used, for example, in the high-definition trailers on Apple's site).

Extensions

Main article: ISO base media file format, MPEG-4 Part 14

The International Organization for Standardization approved the QuickTime file format as the basis of the MPEG-4 file format. The MPEG-4 file format specification was created on the basis of the QuickTime format specification published in 2001.{{cite web |access-date= June 14, 2009 |access-date= June 14, 2009 |access-date= June 14, 2009 |doi-access= free |access-date= June 11, 2009 |access-date= June 11, 2009 |access-date= June 14, 2009 |archive-date= September 10, 2012 |archive-url= https://web.archive.org/web/20120910081136/http://www.mp4ra.org/specs.html |url-status= dead |author-link= International Organization for Standardization |access-date= December 26, 2009 |archive-url = https://web.archive.org/web/20080714101745/http://www.chiariglione.org/mpeg/technologies/mp04-ff/index.htm |archive-date = July 14, 2008}}{{cite web |author-link= International Organization for Standardization |access-date= December 26, 2009}}{{cite web |author-link= International Organization for Standardization |access-date= May 30, 2009}}{{cite web |access-date= June 11, 2009}} A list of all registered extensions for ISO Base Media File Format is published on the official registration authority website www.mp4ra.org. This registration authority for code-points in "MP4 Family" files is Apple Inc. and it is named in Annex D (informative) in MPEG-4 Part 12.

References

References

1. (June 4, 1993). "Video Media Types". IANA.
2. (November 2005). "The Codecs Parameter for "Bucket" Media Types". IETF.
3. (February 14, 2013). "QuickTime File Format". Library of Congress.
4. (March 1, 2001). "QuickTime File Format". Apple.
5. (September 13, 2016). "QuickTime File Format Specification - Document Revision History".
6. Apple Inc.. "QuickTime File Format Specification: Introduction to QuickTime File Format Specification".
7. AfterDawn.com. "QuickTime - AfterDawn.com glossary".
8. "QuickTime container". MultimediaWiki.
9. Apple Inc.. "QuickTime File Format Specification: Movie Atoms".
10. [http://hellninjacommando.com/defilerpak/ DefilerPak – A lightweight codec pack for Windows PCs] {{webarchive. link. (August 15, 2015)
11. [http://www.k-litecodecpack.com/ K-LiteCodecPack.com: Download Codecs, Videos and MP3s]
12. "iTunes Movie Trailers".