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Redirect|MP4Infobox file format| name = MPEG-4 Part 14 (MP4)| icon =| logo =| caption = MPEG-4 Part 14 extends over ISO Base Media File Format (MPEG-4 Part 12).| extension = .mp4, .m4a, .m4p, .m4b, .m4r and .m4v #.MP4 versus .M4A|Bracket|Note 1|| type code = mpg4| uniform type =| magic =| owner = International Organization for Standardization (ISO)| genre = Media container | 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 MPEG-4 Part 14 or MP4 (formally International Organization for Standardization|ISO / International Electrotechnical Commission|IEC 14496-14:2003 ) is a multimedia Container format (digital)|container format standard specified as a part of MPEG-4 . It is most commonly used to store digital video and digital audio streams, especially those defined by MPEG , but can also be used to store other data such as subtitles and still images. Like most modern container formats, MPEG-4 Part 14 allows Streaming media|streaming over the Internet . A separate hint track is used to include streaming information in the file. The only official filename extension for MPEG-4 Part 14 files is .mp4 .
Some devices advertised as " MP4 Player s" are simply MP3 Player s that also play AMV video format|AMV video or some other video format, and do not necessarily play the MPEG-4 part 14 format.cite web|url= http://bj.beareyes.com.cn/2/lib/200510/26/20051026011.htm|title=MP3?MP4!?????MP3?MP4???!|publisher=Beareyescite web|url= http://www.cps365.com/news/200608/06/0712_0000021657.shtml|title=??MP4??:????????????MP4|publisher=??IT?
History of MP4
MPEG-4 Part 14 is an instance of more general International Organization for Standardization|ISO / International Electrotechnical Commission|IEC 14496-12:2004 (MPEG-4 Part 12: ISO base media file format ) which is directly based upon QuickTime File Format .cite web | url = http://www.mp4ra.org/specs.html | author = mp4ra.org - MP4 Registration authority | title = References, MPEG-4 Registration authority | year = | accessdate = 2009-06-14 cite paper | author = ISO | title = ISO Base Media File Format white paper - Proposal | publisher = archive.org | date = 2006-04 | url = http://www.chiariglione.org/mpeg/technologies/mp04-ff/index.htm | accessdate = 2009-12-26 |archiveurl = http://web.archive.org/web/20080714101745/ http://www.chiariglione.org/mpeg/technologies/mp04-ff/index.htm |archivedate = 2008-07-14cite paper | author = ISO | title = MPEG-4 File Formats white paper - Proposal | publisher = archive.org | date = 2005-10 | url = http://www.chiariglione.org/mpeg/technologies/mp04-ff/index.htm | accessdate = 2009-12-26 |archiveurl = http://web.archive.org/web/20080115035235/ http://www.chiariglione.org/mpeg/technologies/mp04-ff/index.htm |archivedate = 2008-01-15cite paper | author = ISO | title = ISO Base Media File Format white paper - Proposal | publisher = chiariglione.org | date = 2009-10 | url = http://mpeg.chiariglione.org/technologies/mpeg-4/mp04-ff/index.htm | accessdate = 2009-12-26 cite web | url = http://images.apple.com/quicktime/pdf/MPEG4_v3.pdf | title = MPEG-4 Fact Sheet | author = Apple Computer 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. http://lists.apple.com/archives/Streaming-server-developers/2001/Dec/msg00016.html RE: QT vs MPEG-4 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.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 | accessdate = 2009-06-11
The MPEG-4 file format specification was created on the basis of the QuickTime format specification published in 2001.cite web | url = http://developer.apple.com/standards/classicquicktime.html | author = Apple Inc. | title = Classic Version of the QuickTime File Format Specification | year = 2001 | accessdate = 2009-06-14 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).cite web | url = http://www.digitalpreservation.gov/formats/fdd/fdd000037.shtml | author = Library of Congress | title = MPEG-4 File Format, Version 1 | year = 2001 | accessdate = 2009-06-14 cite web | url = http://tools.ietf.org/html/rfc4337#page-4 | author = Network Working Group | title = MIME Type Registration for MPEG-4 | year = 2006 | accessdate = 2009-06-14 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 | accessdate = 2009-06-11 In 2003, the first version of 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.cite web | url = http://www.digitalpreservation.gov/formats/fdd/fdd000155.shtml | author = Library of Congress | title = MPEG-4 File Format, Version 2 | year = 2003 | accessdate = 2009-06-14 cite web |url= http://mpeg.chiariglione.org/faq/mp4-sys/sys-faq-sys4gen.htm |title=MPEG-4 Systems General Issues |date=2001-07 |publisher=chiariglione.org |accessdate=2010-04-11 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 , JPEG 2000#Motion JPEG 2000|Motion JPEG 2000 ).cite paper | 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 | accessdate = 2009-05-30 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 | accessdate = 2009-06-11
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 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).cite paper | 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 | format = PDF | pages = 67, 68 | accessdate = 2009-06-12 A list of all registered extensions for ISO Base Media File Format is published on the official registration authority website http://www.mp4ra.org www.mp4ra.org. The registration authority for code-points (identifier values) in "MP4 Family" files is Apple Computer Inc. and it is named in Annex D (informative) in MPEG-4 Part 12. Codec designers should register the codes they invent, but the registration is not mandatorycite web | url = http://www.ftyps.com/mp4reg.html | author = Steven Greenberg | title = Registration of ftyp's | year = 2009 | accessdate = 2009-06-15 and some invented and used code-points are not registered.cite web | url = http://www.ftyps.com/ | author = Steven Greenberg | title = Complete List of all known MP4 / QuickTime 'ftyp' designations | year = 2009 | accessdate = 2009-06-15 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.
Filename extensions
While the only official filename extension defined by the standard is .mp4, various filename extensions are commonly used to indicate intended content:
MPEG-4 files with audio and video generally use the standard .mp4 extension.
Audio-only MPEG-4 files generally have a .m4a extension. This is especially true of non-protected content.
* MPEG-4 files with audio streams encrypted by FairPlay Digital Rights Management as were sold through the iTunes Store use the .m4p extension. iTunes Plus tracks, that the iTunes Store currently sells, are unencrypted and use .m4a accordingly.
* Audio book and podcast files, which also contain metadata including chapter markers, images, and hyperlinks, can use the extension .m4a, but more commonly use the .m4b extension. An .m4a audio file cannot "bookmark" (remember the last listening spot), whereas .m4b extension files can.
*The Apple iPhone uses MPEG-4 audio for its ringtones but uses the .m4r extension rather than the .m4a extension.
Raw MPEG-4 Visual bitstreams are named .m4v but this extension is also sometimes used for video in MP4 container format. http://forum.doom9.org/showthread.php? s=& threadid=62723 Doom9's Forum, MP4 FAQ, Retrieved on 2009-07-15
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 .3gp and .3g2 extensions. These files also store non-MPEG-4 data ( H.263 , AMR, TX3G).
.MP4 versus .M4A
M4A stands for MPEG 4 Audio and is a filename extension used to represent audio files.
The existence of two different filename extensions, .MP4 and .M4A, for naming audio-only MP4 files has been a source of confusion among users and multimedia playback software. Some file manager s, such as Windows Explorer , look up the media type and associated applications of a file based on its filename extension. But since MPEG-4 Part 14 is a container format, MPEG-4 files may contain any number of audio, video, and even subtitle streams, making it impossible to determine the type of streams in an MPEG-4 file based on its filename extension alone. In response, Apple Inc. started using and popularizing the .m4a filename extension, which is used for MP4 containers with audio data in the Advanced Audio Coding (AAC) or its own Apple Lossless (ALE, ALAC) formats. Software capable of audio/video playback should recognize files with either .m4a or .mp4 filename extensions, as would be expected, since there are no file format differences between the two. Most software capable of creating MPEG-4 audio will allow the user to choose the filename extension of the created MPEG-4 files.
Data streams
Unreferenced section|date=July 2011Almost any kind of data can be embedded in MPEG-4 Part 14 files through private streams . The registered codecs for MPEG-4 Part 12-based files are published on the website of MP4 Registration authority (mp4ra.org),mp4ra.org - MP4 Registration authority, http://www.mp4ra.org/codecs.html Registered Types - Codecs - ISO Code Points, Retrieved on 2009-07-14. but most of them are not widely supported by MP4 players. The widely-supported codecs and additional data streams are:Citation needed|date=July 2009
Video: H.264/MPEG-4 AVC|MPEG-4 Part 10 (H.264) and MPEG-4 Part 2
: Other compression formats are less used: MPEG-2 and MPEG-1
Audio: Advanced Audio Coding
: 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
Subtitles: MPEG-4 Part 17|MPEG-4 Timed Text (also known as 3GPP Timed Text).
: Nero Digital uses DVD Video subtitles in MP4 files
Metadata
MP4 files can contain metadata as defined by the format standard, and in addition, can contain Extensible Metadata Platform (XMP) metadata.Citation needed|reason=AFAIK XMP is not part of the MPEG-4 Part 14 standard|date=May 2010
See also
Container format (digital) definition and article
Comparison of container formats|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 codecs
References
Reflist|2
External links
http://www.mp4ra.org/index.html The MP4 registration authority
