MP4 file format explained

MP-4 Part 14
Extension:.mp4, .m4a, .m4p, .m4b, .m4r and .m4v
Mime:video/mp4
audio/mp4
Type Code:mpg4
Owner:International Organization for Standardization

International Electrotechnical Commission
Latest Release Version:ISO/IEC 14496-14:2020
Type:Container format
Container For:Audio, video and text
Extended From:QuickTime File Format and MPEG-4 Part 12
Standard:ISO/IEC 14496-14
Open:No[1]
Free:No[2]

MPEG-4 Part 14, or MP4, is a digital multimedia container format most commonly used to store video and audio, but it can also be used to store other data such as subtitles and still images. Like most modern container formats, it allows streaming over the Internet. The only filename extension for MPEG-4 Part 14 files as defined by the specification is .mp4. MPEG-4 Part 14 (formally ISO/IEC 14496-14:2003) is a standard specified as a part of MPEG-4.

Portable media players are sometimes advertised as "MP4 players", although some are simply MP3 players that also play AMV video or some other video format and do not necessarily play the MPEG-4 Part 14 format.

History

MPEG-4 Part 14 is an instance of the more general ISO/IEC 14496-12:2004 (MPEG-4 Part 12: ISO base media file format), which is directly based upon the QuickTime File Format, which was published in 2001.[3] [4] [5] [6] [7] [8] MPEG-4 Part 14 is essentially identical to the QuickTime File Format but formally specifies support for Initial Object Descriptors (IOD) and other MPEG features.[9] MPEG-4 Part 14 revises and completely replaces Clause 13 of ISO/IEC 14496-1 (MPEG-4 Part 1: Systems), in which the file format for MPEG-4 content was previously specified.[10]

The MPEG-4 file format, version 1, was published in 2001 as ISO/IEC 14496-1:2001, which is a revision of the MPEG-4 Part 1: Systems specification published in 1999 (ISO/IEC 14496-1:1999).[11] [12] [13] In 2003, the first version of the MP4 file format was revised and replaced by MPEG-4 Part 14: MP4 file format (ISO/IEC 14496-14:2003), commonly named as MPEG-4 file format version 2.[14] [15] The MP4 file format was generalized into the ISO Base Media File format ISO/IEC 14496-12:2004, which defines a general structure for time-based media files. It in turn is used as the basis for other file formats in the family (for example, MP4, 3GP, and Motion JPEG 2000).[16] [17]

MP4 file format versions
VersionRelease dateStandardDescriptionEdition
12001ISO/IEC 14496-1:2001MPEG-4 Part 1: SystemsFirst
22003ISO/IEC 14496-14:2003MPEG-4 Part 14: MP4 file formatFirst
22018ISO/IEC 14496-14:2018MPEG-4 Part 14: MP4 file formatSecond
22020ISO/IEC 14496-14:2020MPEG-4 Part 14: MP4 file formatThird

The MP4 file format defined some extensions over the ISO Base Media File Format to support MPEG-4 visual/audio codecs and various MPEG-4 Systems features such as object descriptors and scene descriptions. Some of these extensions are also used by other formats based on the ISO base media file format (e.g., 3GP).[18] A list of all registered extensions for ISO Base Media File Format is published on the official registration authority website. The registration authority for code-points (identifier values) in "MP4 Family" files is Apple Inc., and it is named in Annex D (informative) in MPEG-4 Part 12. Codec designers should register the codes they invent, but registration is not mandatory,[19] and some invented and used code-points are not registered.[20] When someone is creating a new specification derived from the ISO Base Media File Format, all the existing specifications should be used both as examples and as a source of definitions and technology. If an existing specification already covers how a particular media type is stored in the file format (e.g., MPEG-4 audio or video in MP4), that definition should be used, and a new one should not be invented.

Filename extensions

While the only filename extension defined by the standard is, various filename extensions are commonly used to indicate intended content:

Data streams

Most kinds of data can be embedded in MPEG-4 Part 14 files through private streams. A separate hint track is used to include streaming information in the file. The registered codecs for MPEG-4 Part 12-based files are published on the website of MP4 Registration authority (mp4ra.org),[22] but most of them are not widely supported by MP4 players. The widely supported codecs and additional data streams are (but many more are also supported, including audio like FLAC or TrueHD):[23] [24]

Other compression formats are less used: MPEG-2 and MPEG-1

Also MPEG-4 Part 3 audio objects, such as Audio Lossless Coding (ALS), Scalable Lossless Coding (SLS), MP3, MPEG-1 Audio Layer II (MP2), MPEG-1 Audio Layer I (MP1), CELP, HVXC (speech), TwinVQ, Text To Speech Interface (TTSI) and Structured Audio Orchestra Language (SAOL)

Other compression formats are less used: Apple Lossless, Free Lossless Audio Codec (added in late 2018), and Opus (added in late 2018) [26]

Nero Digital uses DVD Video subtitles in MP4 files

The moov atom contains information about video resolution, frame rates, orientation, display characteristics, and more. It might be placed at the beginning or end of the file. In the latter case, the video file is not playable if the file is incomplete (truncated).[27] [28] [29] [30]

Metadata

MP4 files can contain metadata as defined by the format standard, and in addition, can contain Extensible Metadata Platform (XMP) metadata.

See also

External links

Notes and References

  1. . Standard . ISO/IEC 14496-14:2020 . Information technology – Coding of audio-visual objects – Part 14: MP4 file format . 3rd . January 2020 . subscription.
  2. Library of Congress . Washington, D.C. . Sustainability of Digital Formats . Full draft . MPEG-4 File Format, Version 2 . 25 April 2023 . 23 February 2024.
  3. Web site: Classic Version of the QuickTime File Format Specification. Apple Inc.. 2001. 2009-06-14. 2009-08-28. https://web.archive.org/web/20090828000723/http://developer.apple.com/standards/classicquicktime.html. live.
  4. Web site: References, MPEG-4 Registration authority. mp4ra.org - MP4 Registration authority. 2018-08-29. 2018-08-19. https://web.archive.org/web/20180819085633/http://mp4ra.org/#/references. live.
  5. Web site: International Organization for Standardization. Leonardo Chiariglione. ISO Base Media File Format white paper - Proposal. April 2006. 2009-12-26 . https://web.archive.org/web/20080714101745/http://www.chiariglione.org/mpeg/technologies/mp04-ff/index.htm . 2008-07-14.
  6. Web site: International Organization for Standardization. Leonardo Chiariglione. MPEG-4 File Formats white paper - Proposal. October 2005. 2009-12-26 . https://web.archive.org/web/20080115035235/http://www.chiariglione.org/mpeg/technologies/mp04-ff/index.htm . 2008-01-15.
  7. Web site: . Leonardo Chiariglione . ISO Base Media File Format white paper - Proposal . October 2009 . 2014-10-31 . 2021-04-29 . https://web.archive.org/web/20210429224925/https://mpeg.chiariglione.org/technologies/mpeg-4/mp04-ff/index.htm . live.
  8. Web site: MPEG-4 Fact Sheet . https://web.archive.org/web/20141031153948/https://images.apple.com/quicktime/pdf/MPEG4_v3.pdf . 2014-10-31 . Apple Computer.
  9. Web site: RE: QT vs MPEG-4 . 2007-03-30 . https://web.archive.org/web/20070510091152/http://lists.apple.com/archives/Streaming-server-developers/2001/Dec/msg00016.html . 2007-05-10 .
  10. Web site: MPEG-4 Part 14: MP4 file format; ISO/IEC 14496-14:2003. International Organization for Standardization. 2003. 2009-06-11. 2016-10-10. https://web.archive.org/web/20161010071532/http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=38538. live.
  11. Web site: MPEG-4 File Format, Version 1. Library of Congress. 2001. 2009-06-14. 2017-03-20. https://web.archive.org/web/20170320004230/http://www.digitalpreservation.gov/formats/fdd/fdd000037.shtml. live.
  12. Web site: MIME Type Registration for MPEG-4. Y. Lim. D. Singer. RFC Editor. 2006. 10.17487/RFC4337. 2009-06-14. 2021-05-06. https://web.archive.org/web/20210506080808/https://tools.ietf.org/html/rfc4337#page-4. live.
  13. Web site: MPEG-4 Part 1: Systems; ISO/IEC 14496-1:2001. International Organization for Standardization. 2001. 2009-06-11. 2016-08-19. https://web.archive.org/web/20160819064806/http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=34903. live.
  14. Web site: MPEG-4 File Format, Version 2. Library of Congress. 2003. 2009-06-14. 2009-06-25. https://web.archive.org/web/20090625020706/http://www.digitalpreservation.gov/formats/fdd/fdd000155.shtml. live.
  15. Web site: MPEG-4 Systems General Issues . July 2001 . chiariglione.org . 2010-04-11 . 2010-04-13 . https://web.archive.org/web/20100413131035/http://mpeg.chiariglione.org/faq/mp4-sys/sys-faq-sys4gen.htm . live .
  16. Web site: ISO/IEC 14496-12:2008, Information technology -- Coding of audio-visual objects -- Part 12: ISO base media file format. International Organization for Standardization. 2008. https://web.archive.org/web/20160706043645/http://standards.iso.org/ittf/PubliclyAvailableStandards/c051533_ISO_IEC_14496-12_2008.zip. dead. July 6, 2016. ZIP. 88, 94. 2009-05-30 .
  17. Web site: MPEG-4 Part 12: ISO base media file format; ISO/IEC 14496-12:2004. International Organization for Standardization. 2004. 2009-06-11. 2016-08-19. https://web.archive.org/web/20160819065727/http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=38539. live.
  18. Web site: 3GPP2. 3GPP2 C.S0050-B Version 1.0, 3GPP2 File Formats for Multimedia Services. Third Generation Partnership Project 2. 18 May 2007. 67, 68. 2009-06-12. https://web.archive.org/web/20091007071048/http://www.3gpp2.org/Public_html/specs/C.S0050-B_v1.0_070521.pdf. 7 October 2009.
  19. Web site: Registration of ftyp's. Steven. Greenberg. 2009. 2009-06-15. 2009-10-24. https://web.archive.org/web/20091024094913/http://www.ftyps.com/mp4reg.html. live.
  20. Web site: Complete List of all known MP4 / QuickTime 'ftyp' designations. Steven. Greenberg. 2009. 2009-06-15. 2018-01-21. https://web.archive.org/web/20180121071024/http://www.ftyps.com/. live.
  21. http://forum.doom9.org/showthread.php?s=&threadid=62723 Doom9's Forum, MP4 FAQ
  22. mp4ra.org - MP4 Registration authority, Registered Types - Codecs - ISO Code Points, Retrieved on 2009-07-14.
  23. Book: Chapman. Nigel. Chapman. Jenny. Digital multimedia. 2004. Wiley. Chichester [u.a.]. 978-0-470-85890-5. 2.. registration.
  24. Web site: The 'MP4' Registration Authority . 2023-08-31 . mp4ra.org . 2023-10-07 . https://web.archive.org/web/20231007124717/https://mp4ra.org/#/codecs . live .
  25. Web site: AV1 Codec ISO Media File Format Binding . 2024-04-27 . aomediacodec.github.io . 2024-04-05 . https://web.archive.org/web/20240405193244/https://aomediacodec.github.io/av1-isobmff/ . live .
  26. Web site: Encapsulation of Opus in ISO Base Media File Format . 2018-08-28 . 2019-01-05 . 2019-01-06 . https://web.archive.org/web/20190106204303/https://vfrmaniac.fushizen.eu/contents/opus_in_isobmff.html . live .
  27. Web site: JK . Das Moov Atom und wo es stehen sollte . JKdigital . de . 25 January 2013 . 11 August 2020 . 11 August 2020 . https://web.archive.org/web/20200811143846/https://jkdigital.de/moov-atom/ . live .
  28. Web site: Fehlerhaft kopierte MP4-Datei reparieren . preamp.org . de-DE . November 2013 . 2020-08-11 . 2020-08-11 . https://web.archive.org/web/20200811152527/http://preamp.org/revenge/fehlerhaft-kopierte-mp4-datei-reparieren . live .
  29. Web site: eZs3 media service . Checking Metadata or Moov Atom Location . www.ezs3.com . 11 August 2020 . 1 March 2011 . 11 August 2020 . https://web.archive.org/web/20200811204404/https://www.ezs3.com/public/Checking_Metadata_or_Moov_Atom_Location.cfm . live .
  30. Web site: Levkov . Maxim . Understanding the MPEG-4 movie atom Adobe Developer Connection . www.adobe.com . Adobe Developer Network . 11 August 2020 . https://web.archive.org/web/20210130152901/https://www.adobe.com/devnet/video/articles/mp4_movie_atom.html . 2021-01-30.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "MP4 file format".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.