View source for MPEG-4 Part 14

{{Short description|MP4; digital format for storing video and audio}}
{{Infobox file format
| name          = MP-4 Part 14
| icon          = 
| logo          = 
| screenshot    = [[File:Relations between ISO Base Media File Format and MP4 File Format.svg|300px]]
| caption       = MPEG-4 Part 14 extends over ISO Base Media File Format (MPEG-4 Part 12).<ref name="3gpp2-vs-3gpp" />
| extension     = .mp4, .m4a, .m4p, .m4b, .m4r and .m4v<sup>{{Bracket|Note 1}}</sup>
| mime          = video/mp4<br>audio/mp4
| type code     = mpg4
| uniform type  = 
| magic         = 
| owner         = [[Organization:International Organization for Standardization|International Organization for Standardization]]<br>[[Organization:International Electrotechnical Commission|International Electrotechnical Commission]]
| released      = {{Start date and age|2001|10|df=yes}}
| latest release version = ISO/IEC 14496-14:2020
| latest release date = {{Start date and age|2020|01|df=yes}}
| type          = Container format
| container for = Audio, video and text
| contained by  = 
| extended from = [[QuickTime File Format]] and MPEG-4 Part 12
| extended to   = 
| standard      = ISO/IEC 14496-14
| open          = Yes
| free          = No<ref>{{cite techreport |publisher=Library of Congress |location=Washington, D.C. |series=Sustainability of Digital Formats |type=Full draft |title=MPEG-4 File Format, Version 2 |date=2 March 2012 |url=https://www.loc.gov/preservation/digital/formats/fdd/fdd000155.shtml |access-date=13 December 2021}}</ref>
}}

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

[[Engineering:Portable media player|Portable media player]]s are sometimes advertised as "MP4 Players", although some are simply MP3 Players that also play [[AMV video format|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 [[Organization:International Organization for Standardization|ISO]]/[[Organization:International Electrotechnical Commission|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.<ref name="quicktime-format-2001">{{cite web
| url = https://developer.apple.com/standards/classicquicktime.html
| author = Apple Inc.
| title = Classic Version of the QuickTime File Format Specification
| year = 2001
| access-date = 2009-06-14
}}</ref> <ref name="mp4ra-org-references">{{cite web|url=http://mp4ra.org/#/references|title=References, MPEG-4 Registration authority|author=mp4ra.org - MP4 Registration authority|access-date=2018-08-29}}</ref><ref name="mpeg4part12">{{cite document
| author = ISO
| title =  ISO Base Media File Format white paper - Proposal
| date = April 2006
| url = http://www.chiariglione.org/mpeg/technologies/mp04-ff/index.htm
| access-date = 2009-12-26 |archive-url = https://web.archive.org/web/20080714101745/http://www.chiariglione.org/mpeg/technologies/mp04-ff/index.htm |archive-date = 2008-07-14}}</ref><ref name="mpeg4part12--old">{{cite document
| author = ISO
| title =  MPEG-4 File Formats white paper - Proposal
| date = October 2005
| url = http://www.chiariglione.org/mpeg/technologies/mp04-ff/index.htm
| access-date = 2009-12-26 |archive-url = https://web.archive.org/web/20080115035235/http://www.chiariglione.org/mpeg/technologies/mp04-ff/index.htm |archive-date = 2008-01-15}}</ref><ref name="mpeg4part12--new">{{cite document
| author = ISO
| title =  ISO Base Media File Format white paper - Proposal
| publisher = chiariglione.org
| date = October 2009
| url = http://mpeg.chiariglione.org/technologies/mpeg-4/mp04-ff/index.htm
| access-date = 2014-10-31 }}</ref><ref>{{cite web | url = https://images.apple.com/quicktime/pdf/MPEG4_v3.pdf | archive-url = https://web.archive.org/web/20141031153948/https://images.apple.com/quicktime/pdf/MPEG4_v3.pdf | url-status = dead | archive-date = 2014-10-31 | title = MPEG-4 Fact Sheet | author = Apple Computer}}</ref> 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.<ref>{{Cite web |url=http://lists.apple.com/archives/Streaming-server-developers/2001/Dec/msg00016.html |title=RE: QT vs MPEG-4<!-- Bot generated title --> |access-date=2007-03-30 |archive-url=https://web.archive.org/web/20070510091152/http://lists.apple.com/archives/Streaming-server-developers/2001/Dec/msg00016.html |archive-date=2007-05-10 |url-status=dead }}</ref> 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.<ref name="ISO-14496-14">{{cite web
| url = http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=38538
| author = International Organization for Standardization
| title = MPEG-4 Part 14: MP4 file format; ISO/IEC 14496-14:2003
| year = 2003
| access-date = 2009-06-11
}}</ref>

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).<ref name="digitalpreservation-ISO-14496-1-2001">{{cite web
| url = http://www.digitalpreservation.gov/formats/fdd/fdd000037.shtml
| author = Library of Congress
| title = MPEG-4 File Format, Version 1
| year = 2001
| access-date = 2009-06-14
}}</ref><ref name="rfc4337">{{cite web
| url = http://tools.ietf.org/html/rfc4337#page-4
| author = Network Working Group
| title = MIME Type Registration for MPEG-4
| year = 2006
| access-date = 2009-06-14
}}</ref><ref name="ISO-14496-1">{{cite web
| url = http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=34903
| author = International Organization for Standardization
| title = MPEG-4 Part 1: Systems; ISO/IEC 14496-1:2001
| year = 2001
| access-date = 2009-06-11
}}</ref> 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.<ref name="digitalpreservation-ISO-14496-14-2003">{{cite web
| url = http://www.digitalpreservation.gov/formats/fdd/fdd000155.shtml
| author = Library of Congress
| title = MPEG-4 File Format, Version 2
| year = 2003
| access-date = 2009-06-14
}}</ref><ref>{{cite web |url=http://mpeg.chiariglione.org/faq/mp4-sys/sys-faq-sys4gen.htm |title=MPEG-4 Systems General Issues |date=July 2001 |publisher=chiariglione.org |access-date=2010-04-11}}</ref> 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, Motion JPEG 2000).<ref name="mp4ra-org-references" /><ref name="mpeg4part12-mp4">{{cite document
| author = ISO
| title = ISO/IEC 14496-12:2008, Information technology -- Coding of audio-visual objects -- Part 12: ISO base media file format
| publisher = International Organization for Standardization
| year = 2008
| url = http://standards.iso.org/ittf/PubliclyAvailableStandards/c051533_ISO_IEC_14496-12_2008.zip
| format = PDF
| pages = 88, 94
| access-date = 2009-05-30 }}</ref><ref name="ISO-14496-12">{{cite web
| url = http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=38539
| author = International Organization for Standardization
| title = MPEG-4 Part 12: ISO base media file format; ISO/IEC 14496-12:2004
| year = 2004
| access-date = 2009-06-11 }}</ref>

{| class="wikitable sortable"
|+MP4 file format versions
|-
! Version
! Release date
! Standard
! Description
|-
| MP4 file format version 1
| 2001
| ISO/IEC 14496-1:2001
| MPEG-4 Part 1 (Systems), First edition
|-
| MP4 file format version 2
| 2003
| ISO/IEC 14496-14:2003
| MPEG-4 Part 14 (MP4 file format), Second edition
|}

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 ISO base media file format (e.g. 3GP).<ref name="3gpp2-vs-3gpp">{{cite document
|author = 3GPP2
|title = 3GPP2 C.S0050-B Version 1.0, 3GPP2 File Formats for Multimedia Services
|publisher = 3GPP2
|date = 18 May 2007
|url = http://www.3gpp2.org/Public_html/specs/C.S0050-B_v1.0_070521.pdf
|pages = 67, 68
|access-date = 2009-06-12
|url-status = dead
|archive-url = https://web.archive.org/web/20091007071048/http://www.3gpp2.org/Public_html/specs/C.S0050-B_v1.0_070521.pdf
|archive-date = 7 October 2009
}}</ref> 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.<ref name="mpeg4part12-mp4" /> Codec designers should register the codes they invent, but the registration is not mandatory<ref name="ftyp-mp4ra">{{cite web
| url = http://www.ftyps.com/mp4reg.html
| first = Steven
| last = Greenberg
| title = Registration of ftyp's
| year = 2009
| access-date = 2009-06-15
}}</ref> and some invented and used code-points are not registered.<ref name="ftyp">{{cite web
| url = http://www.ftyps.com/
| first = Steven
| last = Greenberg
| title = Complete List of all known MP4 / QuickTime 'ftyp' designations
| year = 2009
| access-date = 2009-06-15
}}</ref> 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 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.<ref name="mpeg4part12-mp4" />

==Filename extensions==

While the only [[Filename extension|filename extension]] defined by the standard is {{Mono|.mp4}}, various filename extensions are commonly used to indicate intended content:
* MPEG-4 files with audio and video generally use the standard {{Mono|.mp4}} extension.
* Audio-only MPEG-4 files generally have a {{Mono|.m4a}} extension. This is especially true of unprotected content.
** MPEG-4 files with audio streams encrypted by [[Software:FairPlay|FairPlay]] Digital Rights Management as were sold through the [[ITunes Store|iTunes Store]] use the {{Mono|.m4p}} extension. iTunes Plus tracks, that the iTunes Store currently sells, are unencrypted and use {{Mono|.m4a}} accordingly.
** [[Engineering:Audiobook|Audiobook]] and [[Podcast|podcast]] files, which also contain metadata including chapter markers, images, and hyperlinks, can use the extension {{Mono|.m4a}}, but more commonly use the {{Mono|.m4b}} extension.
**The Apple [[Engineering:IPhone|iPhone]] uses MPEG-4 audio for its ringtones but uses the {{Mono|.m4r}} extension rather than the {{Mono|.m4a}} extension.
* Raw MPEG-4 Visual bitstreams are named {{Mono|.m4v}} but this extension is also sometimes used for video in MP4 container format.<ref>[http://forum.doom9.org/showthread.php?s=&threadid=62723  Doom9's Forum, MP4 FAQ], Retrieved on 2009-07-15</ref>
* [[Engineering:Mobile phone|Mobile phone]]s use 3GP, an implementation of MPEG-4 Part 12 (a.k.a. MPEG-4/JPEG2000 ISO Base Media file format), similar to MP4. It uses {{Mono|.3gp}} and {{Mono|.3g2}} extensions. These files also store non-MPEG-4 data ([[H.263]], AMR, TX3G). In practice, most (if not all) low end phones and feature phones record in this format, as most (if not all) other mobile phones and smartphones record MP4 files using the .mp4 file extension, and some high end phones{{which|date=October 2020}} can record in [[Raw audio format|.raw]].<!--Does this belong here since it is off-topic?--NR--><!--3gp is similar to MP4 and registered H.263 and AMR for use in implementations of MPEG-4 Part 12. See http://www.mp4ra.org/codecs.html--><!--Is this maybe confused with RAW photo or lossless (i.e. FLAC) audio? Or maybe using third-party software?-->

==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),<ref>mp4ra.org - MP4 Registration authority, [http://mp4ra.org/#/codecs Registered Types - Codecs - ISO Code Points], Retrieved on 2009-07-14.</ref> but most of them are not widely supported by MP4 players. The widely supported codecs and additional data streams are:<ref>{{cite book|last1=Chapman|first1=Nigel|last2=Chapman|first2=Jenny|title=Digital multimedia|date=2004|publisher=Wiley|location=Chichester [u.a.]|isbn=9780470858905|edition=2.|url-access=registration|url=https://archive.org/details/digitalmultimedi0000chap}}</ref>{{obsolete source|reason=Current source is book from 2004. Modern support and use of the MP4 container is quite different. H.265 also isn't/cannot be mentioned in the source, since it predates the format by almost a decade.|date=February 2020}}
* Video: [[High Efficiency Video Coding|MPEG-H Part 2 (H.265/HEVC)]], MPEG-4 Part 10 (H.264/AVC) and [[MPEG-4 Part 2]]
: Other compression formats are less used: [[MPEG-2]] and [[MPEG-1]]
* Audio: [[Advanced Audio Coding|Advanced Audio Coding (AAC)]]
: 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: [[Software:Apple Lossless|Apple Lossless]], [[Software:FLAC|Free Lossless Audio Codec]]  (added in late 2018), and [[Software:Opus (audio format)|Opus]] (added in late 2018) <ref>{{cite web |url=https://vfrmaniac.fushizen.eu/contents/opus_in_isobmff.html |title=Encapsulation of Opus in ISO Base Media File Format |date=2018-08-28 |access-date=2019-01-05}}</ref>
* Subtitles: [[MPEG-4 Part 17|MPEG-4 Timed Text]] (also known as 3GPP Timed Text).
: [[Nero Digital]] uses DVD Video subtitles in MP4 files

The so-called '''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).<ref>{{cite web |last1=JK |title=Das Moov Atom und wo es stehen sollte |url=https://jkdigital.de/moov-atom/ |website=JKdigital |language=de |date=25 January 2013}}</ref><ref>{{cite web |title=Fehlerhaft kopierte MP4-Datei reparieren |publisher=preamp.org |url=http://preamp.org/revenge/fehlerhaft-kopierte-mp4-datei-reparieren |language=de-DE |date=November 2013}}</ref><ref>{{cite web |author=eZs3 media service |title=Checking Metadata or Moov Atom Location |url=https://www.ezs3.com/public/Checking_Metadata_or_Moov_Atom_Location.cfm |website=www.ezs3.com |access-date=11 August 2020 |date=1 March 2011}}</ref><ref>{{cite web |last1=Levkov |first1=Maxim |title=Understanding the MPEG-4 movie atom {{!}} Adobe Developer Connection |url=https://www.adobe.com/devnet/video/articles/mp4_movie_atom.html |website=www.adobe.com |publisher=[[Company:Adobe Inc.|Adobe]] Developer Network |access-date=11 August 2020 | archive-url=https://web.archive.org/web/20210130152901/https://www.adobe.com/devnet/video/articles/mp4_movie_atom.html | archive-date=2021-01-13}}</ref>

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

==See also==
*[[ISO base media file format]]
*Comparison of (audio/video) container formats
*[[List of codecs|List of multimedia (audio/video) codecs]]
*List of open source codecs
*[[Comparison of video codecs]]
*[[Comparison of audio coding formats]]
*[[Audio coding format]]
*[[Video coding format]]
*[[High Efficiency Video Coding]]

==References==
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{{Reflist|30em}}

==External links==
*[http://www.mp4ra.org/index.html The MP4 registration authority]
*{{IETF RFC|4337|link=no}} - MIME Type Registration for MPEG-4
*[http://www.cimarronsystems.com/wp-content/uploads/2017/04/Elements-of-the-H.264-VideoAAC-Audio-MP4-Movie-v2_0.pdf Elements of the H.264 Video/AAC Audio MP4 Movie]
{{Compression formats}}
{{MPEG}}
{{ISO standards}}

[[Category:Digital container formats]]
[[Category:MPEG-4]]

pl:MPEG-4 część 14

{{Sourceattribution|MPEG-4 Part 14|1}}