MPEG Encoding

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.John Watkinson, ''The MPEG Handbook'', p. 1 Together with JPEG, MPEG is organized under ISO/IEC JTC 1/ SC 29 – ''Coding of audio, picture, multimedia and hypermedia information'' (ISO/IEC Joint Technical Committee 1, Subcommittee 29).

MPEG formats are used in various multimedia systems. The most well known older MPEG media formats typically use MPEG-1, MPEG-2, and MPEG-4 AVC media coding and MPEG-2 systems transport streams and program streams. Newer systems typically use the MPEG base media file format and dynamic streaming (a.k.a. MPEG-DASH).

History

MPEG was established in 1988 by the initiative of Dr. Hiroshi Yasuda ( NTT) and Dr. Leonardo Chiariglione ( CSELT). Chiariglione was the group's chair (called Convenor in ISO/IEC terminology) from its inception until June 6, 2020. The first MPEG meeting was in May 1988 in Ottawa, Canada.

Starting around the time of the MPEG-4 project in the late 1990s and continuing to the present, MPEG had grown to include approximately 300–500 members per meeting from various industries, universities, and research institutions.

On June 6, 2020, the MPEG section of Chiariglione's personal website was updated to inform readers that he had retired as Convenor, and he said that the MPEG group (then SC 29/WG 11) "was closed". Chiariglione described his reasons for stepping down in his personal blog. His decision followed a restructuring process within SC 29, in which "some of the subgroups of WG 11 (MPEG) ecamedistinct MPEG working groups (WGs) and advisory groups (AGs)" in July 2020. Prof. Jörn Ostermann of University of Hannover was appointed as Acting Convenor of SC 29/WG 11 during the restructuring period and was then appointed Convenor of SC 29's Advisory Group 2, which coordinates MPEG overall technical activities.

The MPEG structure that replaced the former Working Group 11 includes three Advisory Groups (AGs) and seven Working Groups (WGs)
* SC 29/AG 2: MPEG Technical Coordination (Convenor: Prof. Joern Ostermann of University of Hannover, Germany)
* SC 29/AG 3: MPEG Liaison and Communication (Convenor: Prof. Kyuheon Kim of Kyung Hee University, Korea)
* SC 29/AG 5: MPEG Visual Quality Assessment (Convenor: Dr. Mathias Wien of RWTH Aachen University, Germany)
* SC 29/WG 2: MPEG Technical Requirements (Convenor: Dr. Igor Curcio of Nokia, Finland)
* SC 29/WG 3: MPEG Systems (Convenor: Dr. Youngkwon Lim of Samsung, Korea)
* SC 29/WG 4: MPEG Video Coding (Convenor: Prof. Lu Yu of Zhejiang University, China)
* SC 29/WG 5: MPEG Joint Video Coding Team with ITU-T SG16 (Convenor: Prof. Jens-Rainer Ohm of RWTH Aachen University, Germany; formerly co-chairing with Dr.  Gary Sullivan of Microsoft, United States)
* SC 29/WG 6: MPEG Audio coding (Convenor: Dr. Schuyler Quackenbush of Audio Research Labs, United States)
* SC 29/WG 7: MPEG 3D Graphics coding (Convenor: Prof. Marius Preda of Institut Mines-Télécom SudParis)
* SC 29/WG 8: MPEG Genomic coding (Convenor: Dr. Marco Mattavelli of EPFL, Switzerland)

The first meeting under the current structure was held in October 2020. It (and all other MPEG meetings starting in April 2020) was held virtually by teleconference due to the COVID-19 pandemic.

Cooperation with other groups

MPEG-2

MPEG-2 development included a joint project between MPEG and ITU-T Study Group 15 (which later became ITU-T SG16), resulting in publication of the MPEG-2 Systems standard (ISO/IEC 13818-1, including its transport streams and program streams) as ITU-T H.222.0 and the MPEG-2 Video standard (ISO/IEC 13818-2) as ITU-T H.262. Sakae Okubo (NTT), was the ITU-T coordinator and chaired the agreements on its requirements.

Joint Video Team

Joint Video Team (JVT) was joint project between ITU-T SG16/Q.6 (Study Group 16 / Question 6) – VCEG (Video Coding Experts Group) and ISO/IEC JTC 1/SC 29/WG 11 – MPEG for the development of a video coding ITU-T Recommendation and ISO/IEC International Standard. It was formed in 2001 and its main result was H.264/MPEG-4 AVC (MPEG-4 Part 10), which reduces the data rate for video coding by about 50%, as compared to the then-current ITU-T H.262 / MPEG-2 standard. The JVT was chaired by Dr. Gary Sullivan, with vice-chairs Dr. Thomas Wiegand of the Heinrich Hertz Institute in Germany and Dr. Ajay Luthra of Motorola in the United States.

Joint Collaborative Team on Video Coding

Joint Collaborative Team on Video Coding (JCT-VC) was a group of video coding experts from ITU-T Study Group 16 (VCEG) and ISO/IEC JTC 1/SC 29/WG 11 (MPEG). It was created in 2010 to develop High Efficiency Video Coding (HEVC, MPEG-H Part 2, ITU-T H.265), a video coding standard that further reduces by about 50% the data rate required for video coding, as compared to the then-current ITU-T H.264 / ISO/IEC 14496-10 standard. JCT-VC was co-chaired by Prof. Jens-Rainer Ohm and Gary Sullivan.

Joint Video Experts Team

Joint Video Experts Team (JVET) is a joint group of video coding experts from ITU-T Study Group 16 (VCEG) and ISO/IEC JTC 1/SC 29/WG 11 (MPEG) created in 2017 after an exploration phase that began in 2015. JVET developed Versatile Video Coding (VVC, MPEG-I Part 3, ITU-T H.266), completed in July 2020, which further reduces the data rate for video coding by about 50%, as compared to the then-current ITU-T H.265 / HEVC standard, and the JCT-VC was merged into JVET in July 2020. Like JCT-VC, JVET was co-chaired by Jens-Rainer Ohm and Gary Sullivan, until July 2021 when Ohm became the sole chair (after Sullivan became the chair of SC 29).

Standards

The MPEG standards consist of different ''Parts''. Each ''Part'' covers a certain aspect of the whole specification. The standards also specify '' profiles'' and ''levels''. ''Profiles'' are intended to define a set of tools that are available, and ''Levels'' define the range of appropriate values for the properties associated with them. Some of the approved MPEG standards were revised by later amendments and/or new editions.

The primary early MPEG compression formats and related standards include:
*MPEG-1 (1993): ''Coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbit/s'' (ISO/IEC 11172). This initial version is known as a lossy fileformat and is the first MPEG compression standard for audio and video. It is commonly limited to about 1.5 Mbit/s although the specification is capable of much higher bit rates. It was basically designed to allow moving pictures and sound to be encoded into the bitrate of a Compact Disc. It is used on Video CD and can be used for low-quality video on DVD Video. It was used in digital satellite/cable TV services before MPEG-2 became widespread. To meet the low bit requirement, MPEG-1 downsamples the images, as well as uses picture rates of only 24–30 Hz, resulting in a moderate quality. It includes the popular MPEG-1 Audio Layer III ( MP3) audio compression format.
*MPEG-2 (1996): ''Generic coding of moving pictures and associated audio information'' (ISO/IEC 13818). Transport, video and audio standards for broadcast-quality television. MPEG-2 standard was considerably broader in scope and of wider appeal – supporting interlacing and high definition. MPEG-2 is considered important because it was chosen as the compression scheme for over-the-air digital television ATSC, DVB and ISDB, digital satellite TV services like Dish Network, digital cable television signals, SVCD and DVD Video.''The MPEG Handbook'', p. 4 It is also used on Blu-ray Discs, but these normally use MPEG-4 Part 10 or SMPTE VC-1 for high-definition content.
* MPEG-4 (1998): ''Coding of audio-visual objects''. (ISO/IEC 14496) MPEG-4 provides a framework for more advanced compression algorithms potentially resulting in higher compression ratios compared to MPEG-2 at the cost of higher computational requirements. MPEG-4 also supports Intellectual Property Management and Protection (IPMP), which provides the facility to use proprietary technologies to manage and protect content like digital rights management. It also supports MPEG-J, a fully programmatic solution for creation of custom interactive multimedia applications ( Java application environment with a Java API) and many other features. Two new higher-efficiency video coding standards (newer than MPEG-2 Video) are included:
** MPEG-4 Part 2 (including its Simple and Advanced Simple profiles) and
** MPEG-4 AVC (MPEG-4 Part 10 or ITU-T H.264, 2003). MPEG-4 AVC may be used on HD DVD and Blu-ray Discs, along with VC-1 and MPEG-2.
MPEG-4 AVC was chosen as the video compression scheme for over-the-air television broadcasting in Brazil (ISDB-TB), based on the digital television system of Japan (ISDB-T).

An MPEG-3 project was cancelled. MPEG-3 was planned to deal with standardizing scalable and multi-resolution compression and was intended for HDTV compression, but was found to be unnecessary and was merged with MPEG-2; as a result there is no MPEG-3 standard. The cancelled MPEG-3 project is not to be confused with MP3, which is MPEG-1 or MPEG-2 Audio Layer III.

In addition, the following standards, while not sequential advances to the video encoding standard as with MPEG-1 through MPEG-4, are referred to by similar notation:
* MPEG-7 (2002): ''Multimedia content description interface''. (ISO/IEC 15938)
* MPEG-21 (2001): ''Multimedia framework (MPEG-21)''. (ISO/IEC 21000) MPEG describes this standard as a '' multimedia framework'' and provides for intellectual property management and protection.

Moreover, more recently than other standards above, MPEG has produced the following international standards; each of the standards holds multiple MPEG technologies for a variety of applications. (For example, MPEG-A includes a number of technologies on multimedia application format.)
* MPEG-A (2007): ''Multimedia application format (MPEG-A)''. (ISO/IEC 23000) (e.g., an explanation of the purpose for multimedia application formats, MPEG music player application format, MPEG photo player application format and others)
* MPEG-B (2006): ''MPEG systems technologies''. (ISO/IEC 23001) (e.g., Binary MPEG format for XML, Fragment Request Units (FRUs), Bitstream Syntax Description Language (BSDL) and others)
* MPEG-C (2006): ''MPEG video technologies''. (ISO/IEC 23002) (e.g., accuracy requirements for implementation of integer-output 8x8 inverse discrete cosine transform and others)
* MPEG-D (2007): ''MPEG audio technologies''. (ISO/IEC 23003) (e.g., MPEG Surround, SAOC-Spatial Audio Object Coding and USAC-Unified Speech and Audio Coding)
* MPEG-E (2007): ''Multimedia Middleware''. (ISO/IEC 23004) (a.k.a. M3W) (e.g., architecture, multimedia application programming interface (API), component model and others)
*MPEG-G (2019) ''Genomic Information Representation'' (ISO/IEC 23092), Parts 1–6 for transport and storage, coding, metadata and APIs, reference software, conformance, and annotations
*''Supplemental media technologies'' (2008, later replaced and withdrawn). (ISO/IEC 29116) It had one published part, media streaming application format protocols, which was later replaced and revised in MPEG-M Part 4's MPEG extensible middleware (MPEG-M) protocols.
* MPEG-V (2011): ''Media context and control''. (ISO/IEC 23005) (a.k.a. Information exchange with Virtual Worlds) (e.g., Avatar characteristics, Sensor information, Architecture and others)
* MPEG-M (2010): ''MPEG eXtensible Middleware (MXM)''. (ISO/IEC 23006) (e.g., MXM architecture and technologies, API, and MPEG extensible middleware (MXM) protocols)
* MPEG-U (2010): '' Rich media user interfaces''. (ISO/IEC 23007) (e.g., Widgets)
* MPEG-H (2013): ''High Efficiency Coding and Media Delivery in Heterogeneous Environments''. (ISO/IEC 23008) Part 1 – MPEG media transport; Part 2 – High Efficiency Video Coding (HEVC, ITU-T H.265); Part 3 – 3D Audio.
* MPEG-DASH (2012): ''Information technology – Dynamic adaptive streaming over HTTP (DASH)''. (ISO/IEC 23009) Part 1 – Media presentation description and segment formats
* MPEG-I (2020): ''Coded Representation of Immersive Media'' (ISO/IEC 23090), including Part 2 Omnidirectional Media Format (OMAF) and Part 3 – Versatile Video Coding (VVC, ITU-T H.266)
* MPEG-CICP (ISO/IEC 23091) ''Coding-Independent Code Points'' (CICP), Parts 1–4 for systems, video, audio, and usage of video code points

Standardization process

A standard published by ISO/IEC is the last stage of an approval process that starts with the proposal of new work within a committee. Stages of the standard development process include:
* NP or NWIP – New Project or New Work Item Proposal
* AWI – Approved Work Item
* WD – Working Draft
* CD or CDAM – Committee Draft or Committee Draft Amendment
* DIS or DAM – Draft International Standard or Draft Amendment
* FDIS or FDAM – Final Draft International Standard or Final Draft Amendment
* IS or AMD – International Standard or Amendment

Other abbreviations:
* DTR – Draft Technical Report (for information)
* TR – Technical Report
* DCOR – Draft Technical Corrigendum (for corrections)
* COR – Technical Corrigendum

A proposal of work (New Proposal) is approved at the Subcommittee level and then at the Technical Committee level (SC 29 and JTC 1, respectively, in the case of MPEG). When the scope of new work is sufficiently clarified, MPEG usually makes open "calls for proposals". The first document that is produced for audio and video coding standards is typically called a test model. When a sufficient confidence in the stability of the standard under development is reached, a Working Draft (WD) is produced. When a WD is sufficiently solid (typically after producing several numbered WDs), the next draft is issued as a Committee Draft (CD) (usually at the planned time) and is sent to National Bodies (NBs) for comment. When a consensus is reached to proceed to the next stage, the draft becomes a Draft International Standard (DIS) and is sent for another ballot. After a review and comments issued by NBs and a resolution of comments in the working group, a Final Draft International Standard (FDIS) is typically issued for a final approval ballot. The final approval ballot is voted on by National Bodies, with no technical changes allowed (a yes/no approval ballot). If approved, the document becomes an International Standard (IS). In cases where the text is considered sufficiently mature, the WD, CD, and/or FDIS stages can be skipped. The development of a standard is completed when the FDIS document has been issued, with the FDIS stage only being for final approval, and in practice, the FDIS stage for MPEG standards has always resulted in approval.

See also

* Video Coding Experts Group (VCEG)
* Joint Photographic Experts Group (JPEG)
*Joint Bi-level Image Experts Group (JBIG)
* Multimedia and Hypermedia information coding Expert Group (MHEG)
* Alliance for Open Media (AOMedia)
* Audio codec
* Audio coding format
* Video codec
*Video coding format
* Video quality
* Video compression
* MP3

Notes

External links

*
Papers and books on MPEG

{{Authority control

Computer file formats
Film and video technology
MPEG
Organizations established in 1988
Working groups