MP4 file format

Last updated
MP-4 Part 14
Relations between ISO Base Media File Format and MP4 File Format.svg
MPEG-4 Part 14 extends over ISO Base Media File Format (MPEG-4 Part 12). [1]
Filename extension
.mp4, .m4a, .m4p, .m4b, .m4r and .m4v [Note 1]
Internet media type
video/mp4
audio/mp4
Type code mpg4
Magic number p
Developed by International Organization for Standardization

International Electrotechnical Commission
Initial releaseOctober 2001;23 years ago (2001-10)
Latest release
ISO/IEC 14496-14:2020
January 2020;5 years ago (2020-01)
Type of format Container format
Container for Audio, video and text
Extended from QuickTime File Format and MPEG-4 Part 12
Standard ISO/IEC 14496-14
Open format?No [2] [3]
Free format?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.

Contents

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. [4] [5] [6] [7] [8] [9] 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. [10] 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. [11]

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). [12] [13] [14] 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. [15] [16] 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). [5] [17] [18]

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). [1] 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. [17] 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. [17]

Filename extensions

While the only filename extension defined by the standard is .mp4, 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

Related Research Articles

<span class="mw-page-title-main">Moving Picture Experts Group</span> Alliance of working groups for multimedia coding

The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by ISO and IEC that sets standards for media coding, including compression coding of audio, video, graphics, and genomic data; and transmission and file formats for various applications. Together with JPEG, MPEG is organized under ISO/IEC JTC 1/SC 29 – Coding of audio, picture, multimedia and hypermedia information.

MPEG-4 is a group of international standards for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related technology agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG) under the formal standard ISO/IEC 14496 – Coding of audio-visual objects. Uses of MPEG-4 include compression of audiovisual data for Internet video and CD distribution, voice and broadcast television applications. The MPEG-4 standard was developed by a group led by Touradj Ebrahimi and Fernando Pereira.

QuickTime is an extensible multimedia architecture created by Apple, which supports playing, streaming, encoding, and transcoding a variety of digital media formats. The term QuickTime also refers to the QuickTime Player front-end media player application, which is built-into macOS, and was formerly available for Windows.

MPEG-1 Audio Layer II or MPEG-2 Audio Layer II is a lossy audio compression format defined by ISO/IEC 11172-3 alongside MPEG-1 Audio Layer I and MPEG-1 Audio Layer III (MP3). While MP3 is much more popular for PC and Internet applications, MP2 remains a dominant standard for audio broadcasting.

Advanced Audio Coding (AAC) is an audio coding standard for lossy digital audio compression. It was designed to be the successor of the MP3 format and generally achieves higher sound quality than MP3 at the same bit rate.

MPEG-4 Part 3 or MPEG-4 Audio is the third part of the ISO/IEC MPEG-4 international standard developed by Moving Picture Experts Group. It specifies audio coding methods. The first version of ISO/IEC 14496-3 was published in 1999.

3GP is a multimedia container format defined by the Third Generation Partnership Project (3GPP) for 3G UMTS multimedia services.

<span class="mw-page-title-main">High-Efficiency Advanced Audio Coding</span> Audio codec

High-Efficiency Advanced Audio Coding (HE-AAC) is an audio coding format for lossy data compression of digital audio defined as an MPEG-4 Audio profile in ISO/IEC 14496–3. It is an extension of Low Complexity AAC (AAC-LC) optimized for low-bitrate applications such as streaming audio. The usage profile HE-AAC v1 uses spectral band replication (SBR) to enhance the modified discrete cosine transform (MDCT) compression efficiency in the frequency domain. The usage profile HE-AAC v2 couples SBR with Parametric Stereo (PS) to further enhance the compression efficiency of stereo signals.

MPEG-4 Part 2, MPEG-4 Visual is a video encoding specification designed by the Moving Picture Experts Group (MPEG). It belongs to the MPEG-4 ISO/IEC family of encoders. It uses block-wise motion compensation and a discrete cosine transform (DCT), similar to previous encoders such as MPEG-1 Part 2 and H.262/MPEG-2 Part 2.

MPEG-4 Part 17, or MPEG-4 Timed Text (MP4TT), or MPEG-4 Streaming text format is the text-based subtitle format for MPEG-4, published as ISO/IEC 14496-17 in 2006. It was developed in response to the need for a generic method for coding of text as one of the multimedia components within audiovisual presentations.

The Extensible MPEG-4 Textual Format (XMT) is a high-level, XML-based file format for storing MPEG-4 data in a way suitable for further editing. In contrast, the more common MPEG-4 Part 14 (MP4) format is less flexible and used for distributing finished content.

MPEG-4 Part 11Scene description and application engine was published as ISO/IEC 14496-11 in 2005. MPEG-4 Part 11 is also known as BIFS, XMT, MPEG-J. It defines:

QuickTime File Format (QTFF) is a computer file format used natively by the QuickTime framework.

MPEG-4 Audio Lossless Coding, also known as MPEG-4 ALS, is an extension to the MPEG-4 Part 3 audio standard to allow lossless audio compression. The extension was finalized in December 2005 and published as ISO/IEC 14496-3:2005/Amd 2:2006 in 2006. The latest description of MPEG-4 ALS was published as subpart 11 of the MPEG-4 Audio standard in December 2019.

<span class="mw-page-title-main">MPEG-4 SLS</span> Extension to the MPEG-4 Audio standard

MPEG-4 SLS, or MPEG-4 Scalable to Lossless as per ISO/IEC 14496-3:2005/Amd 3:2006 (Scalable Lossless Coding), is an extension to the MPEG-4 Part 3 (MPEG-4 Audio) standard to allow lossless audio compression scalable to lossy MPEG-4 General Audio coding methods (e.g., variations of AAC). It was developed jointly by the Institute for Infocomm Research (I2R) and Fraunhofer, which commercializes its implementation of a limited subset of the standard under the name of HD-AAC. Standardization of the HD-AAC profile for MPEG-4 Audio is under development (as of September 2009).

MPEG Surround, also known as Spatial Audio Coding (SAC) is a lossy compression format for surround sound that provides a method for extending mono or stereo audio services to multi-channel audio in a backwards compatible fashion. The total bit rates used for the core and the MPEG Surround data are typically only slightly higher than the bit rates used for coding of the core. MPEG Surround adds a side-information stream to the core bit stream, containing spatial image data. Legacy stereo playback systems will ignore this side-information while players supporting MPEG Surround decoding will output the reconstructed multi-channel audio.

MPEG-4 Part 20, or MPEG-4 Lightweight Application Scene Representation (LASeR) is a rich media standard dedicated to the mobile, embedded and consumer electronics industries specified by the MPEG standardization group. LASeR is based on SVG Tiny and adds methods for sending dynamic updates and a binary compression format.

G.719 is an ITU-T standard audio coding format providing high quality, moderate bit rate wideband audio coding at low computational load. It was produced through a collaboration between Polycom and Ericsson.

The ISMA Encryption and Authentication, Version 1.1 specification specifies encryption and message authentication services for MPEG-4 over RTP streams. It was defined by the Internet Streaming Media Alliance and published on September 15, 2006.

The ISO base media file format (ISOBMFF) is a container file format that defines a general structure for files that contain time-based multimedia data such as video and audio. It is standardized in ISO/IEC 14496-12, a.k.a. MPEG-4 Part 12, and was formerly also published as ISO/IEC 15444-12, a.k.a. JPEG 2000 Part 12.

References

  1. 1 2 3GPP2 (18 May 2007). "3GPP2 C.S0050-B Version 1.0, 3GPP2 File Formats for Multimedia Services" (PDF). Third Generation Partnership Project 2. pp. 67, 68. Archived from the original (PDF) on 7 October 2009. Retrieved 2009-06-12.{{cite web}}: CS1 maint: numeric names: authors list (link)
  2. 1 2 MPEG-4 File Format, Version 2 (Full draft). Sustainability of Digital Formats. Washington, D.C.: Library of Congress. 25 April 2023. Retrieved 23 February 2024.
  3. ↑ Information technology – Coding of audio-visual objects – Part 14: MP4 file format (Standard) (3rd ed.). ISO. January 2020. ISO/IEC 14496-14:2020.
  4. ↑ Apple Inc. (2001). "Classic Version of the QuickTime File Format Specification". Archived from the original on 2009-08-28. Retrieved 2009-06-14.
  5. 1 2 mp4ra.org - MP4 Registration authority. "References, MPEG-4 Registration authority". Archived from the original on 2018-08-19. Retrieved 2018-08-29.{{cite web}}: CS1 maint: numeric names: authors list (link)
  6. ↑ "ISO Base Media File Format white paper - Proposal". Leonardo Chiariglione. International Organization for Standardization. April 2006. Archived from the original on 2008-07-14. Retrieved 2009-12-26.
  7. ↑ "MPEG-4 File Formats white paper - Proposal". Leonardo Chiariglione. International Organization for Standardization. October 2005. Archived from the original on 2008-01-15. Retrieved 2009-12-26.
  8. ↑ "ISO Base Media File Format white paper - Proposal". Leonardo Chiariglione. International Organization for Standardization. October 2009. Archived from the original on 2021-04-29. Retrieved 2014-10-31.
  9. ↑ Apple Computer. "MPEG-4 Fact Sheet" (PDF). Archived from the original (PDF) on 2014-10-31.
  10. ↑ "RE: QT vs MPEG-4". Archived from the original on 2007-05-10. Retrieved 2007-03-30.
  11. ↑ International Organization for Standardization (2003). "MPEG-4 Part 14: MP4 file format; ISO/IEC 14496-14:2003". Archived from the original on 2016-10-10. Retrieved 2009-06-11.
  12. ↑ Library of Congress (2001). "MPEG-4 File Format, Version 1". Archived from the original on 2017-03-20. Retrieved 2009-06-14.
  13. ↑ Y. Lim; D. Singer (2006). "MIME Type Registration for MPEG-4". RFC Editor. doi:10.17487/RFC4337. Archived from the original on 2021-05-06. Retrieved 2009-06-14.
  14. ↑ International Organization for Standardization (2001). "MPEG-4 Part 1: Systems; ISO/IEC 14496-1:2001". Archived from the original on 2016-08-19. Retrieved 2009-06-11.
  15. ↑ Library of Congress (2003). "MPEG-4 File Format, Version 2". Archived from the original on 2009-06-25. Retrieved 2009-06-14.
  16. ↑ "MPEG-4 Systems General Issues". chiariglione.org. July 2001. Archived from the original on 2010-04-13. Retrieved 2010-04-11.
  17. 1 2 3 "ISO/IEC 14496-12:2008, Information technology -- Coding of audio-visual objects -- Part 12: ISO base media file format". International Organization for Standardization. 2008. pp. 88, 94. Archived from the original (ZIP) on July 6, 2016. Retrieved 2009-05-30.
  18. ↑ International Organization for Standardization (2004). "MPEG-4 Part 12: ISO base media file format; ISO/IEC 14496-12:2004". Archived from the original on 2016-08-19. Retrieved 2009-06-11.
  19. ↑ Greenberg, Steven (2009). "Registration of ftyp's". Archived from the original on 2009-10-24. Retrieved 2009-06-15.
  20. ↑ Greenberg, Steven (2009). "Complete List of all known MP4 / QuickTime 'ftyp' designations". Archived from the original on 2018-01-21. Retrieved 2009-06-15.
  21. ↑ Doom9's Forum, MP4 FAQ Archived 2006-01-11 at the Wayback Machine , Retrieved on 2009-07-15
  22. ↑ mp4ra.org - MP4 Registration authority, Registered Types - Codecs - ISO Code Points Archived 2019-08-23 at the Wayback Machine , Retrieved on 2009-07-14.
  23. ↑ Chapman, Nigel; Chapman, Jenny (2004). Digital multimedia (2. ed.). Chichester [u.a.]: Wiley. ISBN   978-0-470-85890-5.
  24. ↑ "The 'MP4' Registration Authority". mp4ra.org. Archived from the original on 2023-10-07. Retrieved 2023-08-31.
  25. ↑ "AV1 Codec ISO Media File Format Binding". aomediacodec.github.io. Archived from the original on 2024-04-05. Retrieved 2024-04-27.
  26. ↑ "Encapsulation of Opus in ISO Base Media File Format". 2018-08-28. Archived from the original on 2019-01-06. Retrieved 2019-01-05.
  27. ↑ JK (25 January 2013). "Das Moov Atom und wo es stehen sollte". JKdigital (in German). Archived from the original on 11 August 2020. Retrieved 11 August 2020.
  28. ↑ "Fehlerhaft kopierte MP4-Datei reparieren" (in German). preamp.org. November 2013. Archived from the original on 2020-08-11. Retrieved 2020-08-11.
  29. ↑ eZs3 media service (1 March 2011). "Checking Metadata or Moov Atom Location". www.ezs3.com. Archived from the original on 11 August 2020. Retrieved 11 August 2020.{{cite web}}: CS1 maint: numeric names: authors list (link)
  30. ↑ Levkov, Maxim. "Understanding the MPEG-4 movie atom | Adobe Developer Connection". www.adobe.com. Adobe Developer Network. Archived from the original on 2021-01-30. Retrieved 11 August 2020.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.