MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU) is a standard for "the generic coding of moving pictures and associated audio information".It describes a combination of lossy video compression and lossy audio data compression methods, which permit storage and transmission of movies using currently available storage media and transmission bandwidth. While MPEG-2 is not as efficient as newer standards such as H.264/AVC and H.265/HEVC, backwards compatibility with existing hardware and software means it is still widely used, for example in over-the-air digital television broadcasting and in the DVD-Video standard.
MPEG-2 is widely used as the format of digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. It also specifies the format of movies and other programs that are distributed on DVD and similar discs. TV stations, TV receivers, DVD players, and other equipment are often designed to this standard. MPEG-2 was the second of several standards developed by the Moving Pictures Expert Group (MPEG) and is an international standard (ISO/IEC 13818). Parts 1 and 2 of MPEG-2 were developed in a collaboration with ITU-T, and they have a respective catalog number in the ITU-T Recommendation Series.
While MPEG-2 is the core of most digital television and DVD formats, it does not completely specify them. Regional institutions can adapt it to their needs by restricting and augmenting aspects of the standard. See Video profiles and levels.
MPEG-2 includes a Systems section, part 1, that defines two distinct, but related, container formats. One is the transport stream, a data packet format designed to transmit one data packet in four ATM data packets for streaming digital video and audio over fixed or mobile transmission mediums, where the beginning and the end of the stream may not be identified, such as radio frequency, cable and linear recording mediums, examples of which include ATSC/DVB/ISDB/SBTVD broadcasting, and HDV recording on tape. The other is the program stream, an extended version of the MPEG-1 container format with less overhead than transport stream. Program stream is designed for random access storage mediums such as hard disk drives, optical discs and flash memory.
Transport stream file formats include M2TS, which is used on Blu-ray discs, AVCHD on re-writable DVDs and HDV on compact flash cards. Program stream files include VOB on DVDs and Enhanced VOB on the short lived HD DVD. The standard MPEG-2 transport stream contains packets of 188 bytes. M2TS prepends each packet with 4 bytes containing a 2-bit copy permission indicator and 30-bit timestamp.
MPEG-2 Systems is formally known as ISO/IEC 13818-1 and as ITU-T Rec. H.222.0.ISO authorized the "SMPTE Registration Authority, LLC" as the registration authority for MPEG-2 format identifiers. The registration descriptor of MPEG-2 transport is provided by ISO/IEC 13818-1 in order to enable users of the standard to unambiguously carry data when its format is not necessarily a recognized international standard. This provision will permit the MPEG-2 transport standard to carry all types of data while providing for a method of unambiguous identification of the characteristics of the underlying private data.
The Video section, part 2 of MPEG-2, is similar to the previous MPEG-1 standard, but also provides support for interlaced video, the format used by analog broadcast TV systems. MPEG-2 video is not optimized for low bit rates, especially less than 1 Mbit/s at standard definition resolutions. All standards-compliant MPEG-2 Video decoders are fully capable of playing back MPEG-1 Video streams conforming to the Constrained Parameters Bitstream syntax. MPEG-2/Video is formally known as ISO/IEC 13818-2 and as ITU-T Rec. H.262.
With some enhancements, MPEG-2 Video and Systems are also used in some HDTV transmission systems, and is the standard format for over-the-air ATSC digital television.
MPEG-2 introduces new audio encoding methods compared to MPEG-1:
The MPEG-2 Audio section, defined in Part 3 (ISO/IEC 13818-3) of the standard, enhances MPEG-1's audio by allowing the coding of audio programs with more than two channels, up to 5.1 multichannel. This method is backwards-compatible (also known as MPEG-2 BC), allowing MPEG-1 audio decoders to decode the two main stereo components of the presentation. MPEG-2 part 3 also defined additional bit rates and sample rates for MPEG-1 Audio Layer I, II and III.
MPEG-2 BC (backward compatible with MPEG-1 audio formats)
Part 7 (ISO/IEC 13818-7) of the MPEG-2 standard specifies a rather different, non-backwards-compatible audio format kHz, with multichannel, multilingual, and multiprogram capabilities. Advanced Audio is also defined in Part 3 of the MPEG-4 standard.(also known as MPEG-2 NBC ). Part 7 is referred to as MPEG-2 AAC. AAC is more efficient than the previous MPEG audio standards, and is in some ways less complicated than its predecessor, MPEG-1 Audio, Layer 3, in that it does not have the hybrid filter bank. It supports from 1 to 48 channels at sampling rates of 8 to 96
MPEG-2 NBC (Non-Backward Compatible)
MPEG-2 standards are published as parts of ISO/IEC 13818. Each part covers a certain aspect of the whole specification.
|Part||Number||First public release date (First edition)||Latest public release date (edition)||Latest amend- ment||Identical ITU-T Rec.||Title||Description|
|Part 1||ISO/IEC 13818-1||1996||2015||2016||H.222.0||Systems|
|Part 2||ISO/IEC 13818-2||1996||2013||H.262||Video|
|Part 3||ISO/IEC 13818-3||1995||1998||Audio||MPEG-2 BC - backwards compatible with MPEG-1 Audio|
|Part 4||ISO/IEC 13818-4||1998||2004||2009||Conformance testing|
|Part 5||ISO/IEC TR 13818-5||1997||2005||Software simulation|
|Part 6||ISO/IEC 13818-6||1998||1998||2001||Extensions for DSM-CC||extensions for Digital Storage Media Command and Control|
|Part 7||ISO/IEC 13818-7||1997||2006||2007||Advanced Audio Coding (AAC)||MPEG-2 NBC Audio - Non-Backwards Compatible with MPEG-1 Audio|
|Part 8||dropped||10-Bit Video||The work began in 1995, but was terminated in 2007 because of low industry interest.|
|Part 9||ISO/IEC 13818-9||1996||1996||Extension for real time interface for systems decoders|
|Part 10||ISO/IEC 13818-10||1999||1999||Conformance extensions for Digital Storage Media Command and Control (DSM-CC)|
|Part 11||ISO/IEC 13818-11||2004||2004||IPMP on MPEG-2 systems||Intellectual Property Management and Protection on the MPEG-2 system (XML IPMP messages are also defined in ISO/IEC 23001-3 )|
MPEG-2 evolved out of the shortcomings of MPEG-1.
MPEG-1's known weaknesses:
Sakae Okubo of NTT was the ITU-T coordinator for developing the H.262/MPEG-2 Part 2 video coding standard and the requirements chairman in MPEG for the MPEG-2 set of standards.The majority of patents underlying MPEG-2 technology are owned by three companies: Sony (311 patents), Thomson (198 patents) and Mitsubishi Electric (119 patents). Hyundai Electronics (now SK Hynix) developed the first MPEG-2 SAVI (System/Audio/Video) decoder in 1995.
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.mpg, .mpeg, .m2v, .mp2, .mp3 are some of a number of filename extensions used for MPEG-1 or MPEG-2 audio and video file formats.
The DVD-Video standard uses MPEG-2 video, but imposes some restrictions:
HDV is a format for recording and playback of high-definition MPEG-2 video on a DV cassette tape.
MOD and TOD are recording formats for use in consumer digital file-based camcorders.
XDCAM is a professional file-based video recording format.
Application-specific restrictions on MPEG-2 video in the DVB standard:
Allowed resolutions for SDTV:
The ATSC A/53 standard used in the United States, uses MPEG-2 video at the Main Profile @ High Level (MP@HL), with additional restrictions such as the maximum bitrate of 19.39 Mbit/s for broadcast television and 38.8 Mbit/s for cable television, 4:2:0 chroma subsampling format, and mandatory colorimetry information.
ATSC allows the following video resolutions, aspect ratios, and frame/field rates:
ATSC standard A/63 defines additional resolutions and aspect rates for 50 Hz (PAL) signal.
The ATSC specification and MPEG-2 allow the use of progressive frames, even within an interlaced video sequence. For example, a station that transmits 1080i60 video sequence can use a coding method where those 60 fields are coded with 24 progressive frames and metadata instructs the decoder to interlace them and perform 3:2 pulldown before display. This allows broadcasters to switch between 60 Hz interlaced (news, soap operas) and 24 Hz progressive (prime-time) content without ending the MPEG-2 sequence and introducing several seconds of delay as the TV switches formats. This is the reason why 1080p30 and 1080p24 sequences allowed by the ATSC specification are not used in practice.
The 1080-line formats are encoded with 1920 × 1088 pixel luma matrices and 960 × 540 chroma matrices, but the last 8 lines are discarded by the MPEG-2 decoding and display process.
ATSC A/72 is the newest revision of ATSC standards for digital television, which allows the use of H.264/AVC video coding format and 1080p60 signal.
MPEG-2 audio was a contender for the ATSC standard during the DTV "Grand Alliance" shootout, but lost out to Dolby AC-3.
Technical features of MPEG-2 in ATSC are also valid for ISDB-T, except that in the main TS has aggregated a second program for mobile devices compressed in MPEG-4 H.264 AVC for video and AAC-LC for audio, mainly known as 1seg.
MPEG-2 is one of the three supported video coding formats supported by Blu-ray Disc. Early Blu-ray releases typically used MPEG-2 video, but recent releases are almost always in H.264 or occasionally VC-1. Only MPEG-2 video (MPEG-2 part 2) is supported, Blu-ray does not support MPEG-2 audio (parts 3 and 7). Additionally, the container format used on Blu-ray discs is an MPEG-2 transport stream, regardless of which audio and video codecs are used.
As of February 14 2020, MPEG-2 Patents have expired worldwide, with the exception of only Malaysia. The last US patent expired on February 23, 2018.
MPEG LA, a private patent licensing organization, had acquired rights from over 20 corporations and one university to license a patent pool of approximately 640 worldwide patents, which it claimed were "essential" to use of MPEG-2 technology. The patent holders included Sony, Mitsubishi Electric, Fujitsu, Panasonic, Scientific Atlanta, Columbia University, Philips, General Instrument, Canon, Hitachi, JVC Kenwood, LG Electronics, NTT, Samsung, Sanyo, Sharp and Toshiba.Where Software patentability is upheld and patents have not expired (only Malaysia), the use of MPEG-2 requires the payment of licensing fees to the patent holders. Other patents were licensed by Audio MPEG, Inc. The development of the standard itself took less time than the patent negotiations. Patent pooling between essential and peripheral patent holders in the MPEG-2 pool was the subject of a study by the University of Wisconsin.
According to the MPEG-2 licensing agreement any use of MPEG-2 technology in countries with active patents (Malaysia) is subject to royalties.MPEG-2 encoders and decoders are subject to $0.35 per unit. Also, any packaged medium (DVDs/Data Streams) is subject to licence fees according to length of recording/broadcast. The royalties were previously priced higher but were lowered at several points, most recently on January 1 2018. An earlier criticism of the MPEG-2 patent pool was that even though the number of patents had decreased from 1,048 to 416 by June 2013 the license fee had not decreased with the expiration rate of MPEG-2 patents.
The following organizations have held patents for MPEG-2, as listed at MPEG LA. See also List of United States MPEG-2 patents.
|GE Technology Development, Inc.||75|
|CIF Licensing, LLC||44|
|Alcatel Lucent (including Multimedia Patent Trust)||33|
|Cisco Technology, Inc.||13|
|Robert Bosch GmbH||5|
|Nippon Telegraph and Telephone (NTT)||2|
|ARRIS Technology, Inc.||2|
|Hewlett Packard Enterprise Company||1|
MP3 is a coding format for digital audio developed largely by the Fraunhofer Society in Germany, with support from other digital scientists in the US and elsewhere. Originally defined as the third audio format of the MPEG-1 standard, it was retained and further extended — defining additional bit-rates and support for more audio channels — as the third audio format of the subsequent MPEG-2 standard. A third version, known as MPEG 2.5 — extended to better support lower bit rates — is commonly implemented, but is not a recognized standard.
The Moving Picture Experts Group (MPEG) is an alliance of working groups of 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 the JPEG group, MPEG is organized under ISO/IEC JTC 1/SC 29 – Coding of audio, picture, multimedia and hypermedia information.
MPEG-1 is a standard for lossy compression of video and audio. It is designed to compress VHS-quality raw digital video and CD audio down to about 1.5 Mbit/s without excessive quality loss, making video CDs, digital cable/satellite TV and digital audio broadcasting (DAB) practical.
MPEG-4 is a method of defining compression of audio and visual (AV) digital data. It was introduced in late 1998 and designated a standard for 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 AV 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.
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode ray tube (CRT) systems which were later replaced by flat panel displays of several types.
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. Designed to be the successor of the MP3 format, AAC generally achieves higher sound quality than MP3 at the same bit rate.
Advanced Video Coding (AVC), also referred to as H.264 or MPEG-4 Part 10, Advanced Video Coding, is a video compression standard based on block-oriented, motion-compensated integer-DCT coding. It is by far the most commonly used format for the recording, compression, and distribution of video content, used by 91% of video industry developers as of September 2019. It supports resolutions up to and including 8K UHD.
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.
Advanced Television Systems Committee (ATSC) standards are an American set of standards for digital television transmission over terrestrial, cable and satellite networks. It is largely a replacement for the analog NTSC standard and, like that standard, is used mostly in the United States, Mexico, Canada, and South Korea. Several former NTSC users, in particular Japan, have not used ATSC during their digital television transition, because they adopted their own system called ISDB.
H.262 or MPEG-2 Part 2 is a video coding format standardised and jointly maintained by ITU-T Study Group 16 Video Coding Experts Group (VCEG) and ISO/IEC Moving Picture Experts Group (MPEG), and developed with the involvement of many companies. It is the second part of the ISO/IEC MPEG-2 standard. The ITU-T Recommendation H.262 and ISO/IEC 13818-2 documents are identical.
MPEG transport stream or simply transport stream (TS) is a standard digital container format for transmission and storage of audio, video, and Program and System Information Protocol (PSIP) data. It is used in broadcast systems such as DVB, ATSC and IPTV.
MPEG-4 Part 2, MPEG-4 Visual is a video compression format developed by the Moving Picture Experts Group (MPEG). It belongs to the MPEG-4 ISO/IEC standards. It is a discrete cosine transform (DCT) compression standard, similar to previous standards such as MPEG-1 Part 2 and H.262/MPEG-2 Part 2.
MPEG Multichannel is an extension to the MPEG-1 Layer II audio compression specification, as defined in the MPEG-2 Audio standard which allows it provide up to 5.1-channels of audio. To maintain backwards compatibility with the older 2-channel (stereo) audio specification, it uses a channel matrixing scheme, where the additional channels are mixed into the two backwards compatible channels. Extra information in the data stream contains signals to process extra channels from the matrix.
Packetized Elementary Stream (PES) is a specification in the MPEG-2 Part 1 (Systems) and ITU-T H.222.0 that defines carrying of elementary streams in packets within MPEG program streams and MPEG transport streams. The elementary stream is packetized by encapsulating sequential data bytes from the elementary stream inside PES packet headers.
Program stream is a container format for multiplexing digital audio, video and more. The PS format is specified in MPEG-1 Part 1 and MPEG-2 Part 1, Systems. The MPEG-2 Program Stream is analogous and similar to ISO/IEC 11172 Systems layer and it is forward compatible.
MPEG-1 Audio Layer I, commonly abbreviated to MP1, is one of three audio formats included in the MPEG-1 standard. It is a deliberately simplified version of MPEG-1 Audio Layer II, created for applications where lower compression efficiency could be tolerated in return for a less complex algorithm that could be executed with simpler hardware requirements. While supported by most media players, the codec is considered largely obsolete, and replaced by MP2 or MP3.
2D Plus Delta is a method of encoding 3D image listed as a part of MPEG2 and MPEG4 standards, specifically on the H.264 implementation of Multiview Video Coding extension. This technology originally started as a proprietary method for Stereoscopic Video Coding and content deployment that utilizes the Left or Right channel as the 2D version and the optimized difference or disparity (Delta) between that image channel view and a second eye image view is injected into the videostream as user_data, secondary stream, independent stream, enhancement layer or NALu for deployment. The Delta data can be either a spatial stereo disparity, temporal predictive, bidirectional or optimized motion compensation.
Part 3 of the MPEG-2 standard defines audio coding:
ISO/IEC JTC 1/SC 29, entitled Coding of audio, picture, multimedia and hypermedia information, is a standardization subcommittee of the Joint Technical Committee ISO/IEC JTC 1 of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). It develops and facilitates international standards, technical reports, and technical specifications within the field of audio, picture, multimedia, and hypermedia information coding. The standards developed by SC 29 have been recognized by seven Emmy Awards.