INTERNATIONAL
`STANDARD
`
`use/EEC
`11172-2
`
`First edition
`1993—08-01
`
`Information technology — Coding of
`moving pictures and associated audio for
`digital storage media at up to about
`1,5 Mbitls —
`
`Part 2:
`
`Video
`
`Technologies de I’information w» Coa'age de l'image animée et du son
`assocfé pour les- supports de stcckage numérique jusqu'é environ
`1.5 Mbit/s —
`Pam's 2: Video
`
` Reference number
`
`ISO/IEC 11 172-2 1993(E)
`
`Page 1 of 124
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`HTC-LG-SAMSUNG EXHIBIT 10047
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`lSO/iEC 11172-2: 1993 {E}
`
`Conients
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`Page
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`Fmeword ...................................... . ............................................................iii
`
`[ntrocuction
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`Sectien 1: General ........................................................................................ 1
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`1 . I
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`Seepe .............................................................................................. 1
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`1.2
`
`Normatiw referencesl
`
`Section 2: Technical elemen153
`
`2.] Defm1hons3
`
`2.2
`
`Symbols-and abbrethionsll
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`2.3 Method of describing bitslream syntax.................................................... l3
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`2!- Requuements 15
`
`Annexes
`
`A
`
`13
`
`C
`
`8 by S Inverse discrete cosine transionn
`
`m ‘0
`
`Variable lenth cojetahles40
`
`Video buffering verLfier49
`
`D_
`
`Guidetoencodingv1d6051
`
`E Bibliographylos
`
`F
`
`List of patent holders......................................................................... 109
`
`© ISO/{EC 1993
`All rights reserved. No part of this publication may be reproduced or utilized in any form or by
`any means, electronic or mechanical, including photocopying and microfilm without
`permission in writing from the publisher.
`
`ISO/EEC Copyright Office - Case Postaie 56 - CH 1211 Gen‘eve 20 - Switzerland
`
`Printed in Switzerland.
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`© ISO/lEC
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`ISO/[EC 11172~2: 1993 (E)
`
`Foreword
`
`lSO Ithe lnternationai Organization for Standardization) and IEC (the Inter—
`nationa Electrotechnical Commission) form the specialized system for
`worldwide standardization. Na’donal bodies that are members of
`ISO or
`
`lnzemational Standards through
`EEC participate h the development of
`technical committees established by the respective organization 'to deal
`with particular fields oi
`techn-cal activity.
`ISO and IEC technical com-
`mittees collaborate in fields of mutual interest Other international organ—
`lzations, governmental and nongovernmental, in liaison with ISO and lEC,
`also take part n the work.
`
`In the field of informazion technology, :80 and IEC have established a joint
`technical committee, ‘SO/IEC JTC 1. Bart International Standards adopted
`by the loint technical commi.t-ee are circulated to national bodes for vote
`ing Publication as an International Standard requires appovai by at least
`75% o‘ the national bodies casting a vote.
`
`International Standard iSO/IEC 11172-2 was prepared by JOint Technical
`_ Committee ESQ/IEC JTC 1, information technology, Sub-Committee SC 29,
`Coded representation of aJdio, picture multimedia.and hypermedia infor~
`7 matio‘n.
`
`ISDIJEC 11172 consists oi the following parts, under the‘general title in—
`formation technology —' Coding of moving pictures and aesociated audio
`for digital storage media at up to about 1,5 Marys:
`
`'— Part 1‘: Systems
`
`— Part 2: "Video
`
`— Part 3: Audio
`
`—— Part 4: Compliance testing
`
`Annexes A, B and C fom an integral part of this part of lSO/lEC 11172
`Annexes D, E and F are for information only.
`
`
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`tee/rec 11172-2: 1993 (E)
`
`o ISO/IEO
`
`Introduction
`
`Note —- Readers interested in an overview of the MPEG Video layer should read this Introduction and then
`
`proceed to annex D, before returning to clauses I and 2‘
`
`0.1
`
`Purpose
`
`This part ofISDIIEC 11 172 was developed in response to the growing need for a common format for
`representing compressed video on various digital storage media such as CD3, DATs, Winchester disks and
`optical drives. This part of lSO/[EC 11172 specifies a coded representation that can be used for
`compressing video sequences to biuates around 1,5 Mbitls. The use of this part of ISOIEEC 11172 means
`thatmotion video can be manipulated as aform oforanputer data and can be transmitted and received over
`existing and fixture networks. The coded representation can be used with both 625 -Iine and Sij-tine
`television and provides flexibility for use with workstation and personal computer displays.
`
`'Ihis part ofISOIEBC 11172 was developed to operate principally from storage media offering acontinuous
`trarnfer rate of about 1.5 .Vlbitls. Neverthelessit can be used more widely than this because the approach
`taken is generic.
`
`0.1.1 Coding parameters
`
`'lhe intention indcveloping this part of ISOr’IKi 1.1172 has been to define asonroe coding algorithm with a
`large degree of flexibility that can be used in many different applications. To achieve this goal, a number of
`the parameters defining the characteristics ofcoded bitsn-eams and decoders are contained inthe bitstream
`itself! This allows for example, the algorithm to be used for pictures witha variety of sins and aspect
`ratios and on channels or devices operating at awide range of bitrates
`
`Betause of the large range of the characteristics of bitstreams that can he represented by this part of ISOIIEC
`11172. a sub-set of these coding parameters known as the "Constrained Parameters" hasbeen defined. The
`aim in defining the constrained parameters is to offer guidance about a widely useful range ofparameters.
`Conforming to this set of constraints is not a requirement of this part of ISO/IEC 11172. A flag in the
`bitstream indicates whether or not it is a Constrained Paranetets hitstreun.
`
`Summary of the Constrained Parameters:
`
`
`
`
`
`Vertical ricture size
`
`
`
`
`
`
`
`
`
`
`Less thanore at to 576 lines
`Less than or . a a] to 396 macroblocks
`
`Less “more a! m 30 Hz
`
`less than -64 to +615 pets (using half-pol vectors)
`ackwardificode and unward_f_code 4:: 4 see mbleDJ
`
`
`
`
`
`
`Less than ore-uni m 1 856 000 hits/s (constant bitrate
`
`
`
`
`0.2 Overview of the algorithm
`
`The coded representation defined in this part of ISO/IEC 11172 achieves a high compression ratio while
`preserving good picture quality. The algorithm is not lossiess as the exact pcl values are not preserved
`during coding. The choice of the techniques is based on the need to balance a high picture quality and
`compression ratio with the requirement to make random access to the coded bitstream. Obtaining good
`picture quality attire bitrates of interest demands a very high compression ratio which is not achievable
`with intraframe coding alone. In: need for random access, however, is best satisfied with pure intraframe
`coding- This mounts a carefulbalance between ions and intertrame coding and between recursive and non-
`recursive temporal redundancy reduction.
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`© lSO/IEC
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`ISO/[EC 11172-2: 1993 (E)
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`A number of lechniquesare used to achieve a high compression ratio. The first, which is almost
`independent from this part ofISO/[EC 11172, is to select an appropriate spatial resolution for the signal.
`The algorithm then ums blocknhased motion compensation to reduce the temporal redundancy. Motion
`compensation is used for causal prediction of the current picture from a previous picture, for non-causal
`prediction of the cment picture from a futurepicture: or for interpolative prediction from past and future
`pictures. Motion vectors are defined for each 16-pel hy 16—line region of the picture. The difference signal,
`the prediction error. is further compressed using the discrete cosine transform (DCI‘) to remove spatial
`correlation before it is quantized in an irreversible process dist discards the less important informatim.
`Finally, the motion vectors are combined with the DCT information, and coded using variable length codes-
`
`0.2.1 Temporal processing
`
`Because of die conflicting requirements of random access and highly efficient compression, three main
`picture types are defined. Inna-coded pictures (I-Pictures) are coded without reference to other pictures.
`They provide access points to the coded sequence where decoding canbegin, butare ended with only a
`moderate compression ratio. Predictive coded pictures (PAPictures) are codedmore efficiently using motion
`compensated prediction from a pastintraor predictivecoded picture and are generally used as a reference for
`furrlrerprediction. Bidirectionally—predicrive coded pictues (B-Pictures) provide the highest degree of
`compression but require both part and fume reference pictures for motion compensation. Bidirectionally—
`predictive mded pictures are never used as references for prediction The organisation of the three picture
`types in a sequerceis very flexible. The choice is left to the encoder and will depend on the requirements of
`the application. Figure I illustrates the relationship between the three differentpicnrre types.
`
`Bi—d'u'ectional
`
`Prediction
`
`Prediction
`
`Figure l -- Example of temporal picture structure
`
`The fourth picture type defmed in this part of ISO/lEC 11172, the D—picture, is provided to allowa simple,
`but limited quality, fast~forward playback mode.
`
`0.2.2 Motion representation - macrobloclts
`
`The choice of 16 by 16 macrohlocks for line motion-compensation unit is aresult of the trade-off between
`increasing the coding efficiency provided by using motion informao‘on and the Overhead needed to storeit.
`Each macroblock can he one of a number of different types. For example. inns-coded, forward-predictive-
`coded, backward-predictive coded, and bidirectionally~predicrive—coded macrobloclcs are perrm'tted in
`bidirectionally-predictive coded pictures. Depending on the type of the macroblock, motion vector
`information and other side information are stored with the compressed prediction error signal in each
`macrohlock. Themotion vectors are encoded differentially with respect to the last coded motion vector,
`using variable-length codes. The maximum length of the vectors that may berepresented can be
`programmed, on a picture—by—picttue basis, so that the mosr demanding applications can be met without
`compromising the pmnnance of the system in more normal situations.
`
`It is the responsibility of the encoder to calculate appropriate motion vectors. This part of ISO/{EC l1i72
`does not specify how this should be done.
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`_ ISO/“EC 11.1?2-2: 1993 (E)
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`I
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`©ISO/1EC
`
`6.2.3 Spatial redundancy reduction
`
`Both original pictures and prediction error signals have high spatial redundancy. This part of [SO/IEC
`11172 usesa block-based DCT method with visually weighted quantization and run—length coding. Each 8
`by 8 hioek of the original picture for intro-coded macrobloclzs or of the prediction errorfor predictive—wded
`merobloclrs is transformed into the DCT domain where it ’n scaled before being quantized. After
`quant'zation many of the coefficients are zero in value and so two—(Emensional run—length and variable
`length coding is used to encode the remaining coefficients efficiently.
`
`0.3 Encoding
`
`This part of ISOIIBC 11172 does not Specify an encoding process. It specifies the syntax and semantics of
`the bitstream and the signal procesring in the decoder. As a result, many options are left open to encoders
`to trade-off cost and speed against pieture quality and coding efficiency. This clause is abrief description of
`the functions that need to he performed by an encoder. Figure 2shows themain functional blocks
`
`Motion
`
`Source input pictures
`
`stimator
`
`DCT is discrete cosine transform
`
`DC'I‘l is inverse discrete cosine transform
`Q is quantization
`Q'] is dequantization
`VLC is variable length coding
`
`Figure 2 -- Simplified video encoder block diagram
`
`The input video signal or um he digitized and representedas a luminance and two colour difference signals
`(Y, Cb, Cr). This may he followed by preprocessing and format conversion to selectan appropriate
`window. resolution and input format. This part of [SO/113C 11172 requires that the colour difference
`signals (Cb and Cr) are subsarnpled with respect to the luminance by 2:! in both vertical and horizontal
`directions and are reformatted, if necessary, as a non-interlaced signal.
`
`The enooder must choow which picture type to use. for each picture. Having defined the picture types, the
`encoder estimateg motion vectors for each 16 by 16 macroblock in the picture.
`In P~Pictures one vector is
`needed for each non—intro macroblock and in B-Pictnres one or two vectors areneeded.
`
`if B-Picmres are used sonic reordering of the piaure sequence is necessary before encoding. Because B—
`Pictures are coded using bidirectional motion oommnsated prediction, they can only be decoded after the
`subsequent reference picture (an I or P—Picture) hasbeen decoded. Therefore the pictures are reordered by the
`
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`© {SO/IEO
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`ISOl'IEC 11172—2: 1993 (E)
`
`encodersothat the pictures arrive at the decoder in the order fordecoding. The correct d'splay order is
`recovered by the decoder;
`
`The basic unit of coding within a picture is the macrobloclc. Within each picture, macrobloclcs are encoded
`in sequence, left to right, top to bottom. Each macrnblock consists of six 8 by 8 blocks: four blocks of
`luminance, one block of Ch chrominance, and one block of Cr chrominance. See figure 3. Note that the
`picture area covered by the four blocks of luminance is the same as the area covered by each of the
`chrominance blocks. This is due to subsampling of the chrominance information to match the sensitivity of
`the human visual system.
`-
`
`lil-
`
`Y
`
`Ch
`
`Cr
`
`Figure 3 ~-
`
`'Macroblock structure
`
`,
`Firstly, fora given microblock, the coding mode is chosen. It depends on the picture type, the
`effectiveness of motion compensated prediction in that local region, and the nature of the signal within the
`block. Secondly, depending on the coding mode, amotion compensated prediction of the contents of the
`block based on past ancUor future reference pictures is formed. This prediction is subtracted from the actual
`data in the current macroblock to form an error signal. Thirdly, this error signal is separateti into S by 8
`blocks (4 luminance and2 chrominance blocks in each macrobloclc) and a discrete cosine transform is
`performed on each block. Each resulting 8 by 8 block of DCT coefficients is quantized and the two—
`dimensional block is scanned in a zigezag order to convert itinto a one-dimensional suing of quantized DCT
`coefficients. Fourthly, the side—information for the macroblock (mode, motion vectors etc} and the
`quantized coefficient data are encoded. For maximum efficimcy, a number of variable length code tables are
`defined forthc different data elements. Run~length coding is used for the quantized cocfficientdzta
`
`A consequence of using different picture types and variable length coding is that the overall datarate is
`variable In applications tint involve a fixed-rate channel. aFlFO buffer may be used to match the encoder
`output to the channel. The status of this buffer may be monitored to control the number of bits generated
`by the encoder. Controlling the quantization process is the most direct way of controllingthe bitrate. This
`part of ISO/113C 1 1172 specifies an abstractmodel of the buffering system (the Video Buffering Verifier} in
`order to constrain the maximum variability in the number of bits that are used for a given picture. This
`ensures that abitstreatn can be decoded with a buffer of known size.
`
`At this stage, the coded representation of the picture has been generated. The final step in the encoder is to
`regenerate I—Pictures and P-Picnrres by decoding the data so that they can be used as reference pictures for.
`subsequent encoding. The quantized coefficients are dequan tized and an inverse 8 by 8 DC? is performed on
`each block. The prediction error signal produced is then added back to the prediction signal and limited to
`the required range to give a decoded reference picture.
`
`0.4 Decoding
`
`it is considerably simpler than encoding as there is no
`Decoding is the inverse of the encoding operation.
`need to perform motion estimation and there are many fewer options. The decoding procem is defined by
`this part of ISOJIEC 11172. The description that follows is a very brief overview of one possible way of
`decoding abitstreatn. Other decoders with different architectures are possible. Figure 4 shows the main
`functional blocks.
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`lSO/IEC 11172-2: 1993 (E)
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`©__Iso;iEc
`
`
`
`
`Reconstructed
`output pictures
`
`DCT'1 is inverse discrete cosine Unnsfonn
`Q-l
`_ isdequantization
`MUX“1 is demnltiplexing
`VLD
`is variable length decoding
`
`Figure 4 -- Basic video decoder block diagram
`
`For fixed—rate applications, the channel fills a FIFO buffer at a constant rate with the coded bitstrcam. The
`decoder reads this buffer and decodes the data elements in Ihebitstream according to the defined syntax.
`
`As the decoder reads the hitstream, it identifies the start of a coded picturearrd then the type of the picture.
`It decodes molt macrohlock in the picture in turn. The macrobiotic type and the motion vectors, if present,
`are used to construct a prediction of the currentrnacroblock based on past and future referent:- pictures that
`-- have been stored in thedecoder'. The coefficient dataare decoded and dequantized. Each 8 by 8 block of
`coefficient data is transformed by an inverse DCT (specified in annex A), and the result is added to the
`prediction signal and limited to the defined range.
`
`After all the macroblocks in the picture have been processed the picture has been reconstructed If it is an [—
`picture or aP—picture it is a reference picture for subsequent pictures and is stored, replacing the oldest stored
`reference picture. Before the pictures are displayed they may need to be re—ordered from the coded order to '
`their nahtral display order. Aflerr‘eordering the pictures are available, in digital form, for post-processing
`and display in any manner that the application chooses.
`
`0.5
`
`Structure of the coded video bitstream
`
`This part of ISOJIEC 11172 spedfics a syntax for needed video bitstrearn. This syntax contains six layers,
`each of which either supports a signal processing or a system function:
`
`La ers of the max
`
`Sequence layer
`Group ofpictures layer
`Picture layer
`Slice layer
`Macroblock layer
`Blmkla r
`
`DCT unit
`
`Random access unit: context
`Random access unit: video
`Primary coding unit
`Resyrrchronization unit
`Motion compensation unit
`
`0.6 Features supported by the algorithm
`
`Applications rising compressed video on digital storage media need to be able to perform annmber of
`operations in addition to normal forward playback of the signence. The coded bitstreatrt has been designed
`to support a number of these operations.
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`_© ISO/[EC
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`lSO/lEC 11172-2: 1993 (E)
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`0 . 6 .1 Random access
`
`Random access is an essential feature for video 0113 storage medium. Random access requires that any
`picture can be decoded in a l’mited amount of time. It implies the existence of access points in the
`bitstream — that is segments of information that are identifiable and can bedecoded without reference to ether
`segments of data A spacing of two random access points [Ima—Picmres) per secmd can be achieved
`without significant loss of picture quality.
`
`0. 6. 2 Fast search
`
`Depending on the storage medium, it is possible to scan the access points in a coded bitstream (with the
`help of an applicatiomspecific tirectory or other knowledge beyond the scope of this part of ISO/[EC
`ll 17?.) to obtain a last—forward and fast—reverse playback effect.
`
`0.6 . 3 Reverse piayback
`
`Some applications may require the video signal Lobe played in reverse order. This canbe achieved in a
`decoder by using memory to store entire groups ofpictures after. they have been decoded before being
`displayed in reverse order. An encoder can make this feature easier by redrcing the length of groups of
`pictures.
`
`0.5.4 Error robustness
`
`Most digital storage mediaand communication channels are not error—free. Approoriate channel coding
`schemes should be usede are beyond the scope of this part of ISOIIEC 11172. Nevertheless the
`compression scheme defined in this part of ISO/IEC-11172 is robust to residual errors. The slice structure
`allows a decoder torccover after a data error and to resynchmnize its decoding. Therefore! bit errors in the
`compressed data will cause errors in the decoded picurres to be limited in area. Decoders may be able to use
`comealment strategies to disguise Lhese errors.
`
`0.6.5 Editing
`
`Thereis a conflict between the requirement for high coding efficiency and easy editing. The coding structure
`and syntax have not been designed with the primary aim of simplifying editing at any picture. Nevertheless
`a number of features have been included that enable editing of coded data
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`tNTERNATIONAL STANDARD © ISO/IE0 ISO/EEC 11172-2: 1993 (E)
`
`Information technology —- Coding of moving
`pictures and associated audio for digital storage
`media at up to about 15 Mbit/s —
`
`Part 2:
`Video
`
`Section 1: General
`
`1.1
`
`Scope
`
`This part of ISO'IEC 11172 specifies the coded representation of video for digital storage media and
`specifies the decoding process. The representation supports normal speed forward playback, as well as
`special functions such as random access, fast forward playback, fast reverse playback, normal speed reverse
`playback, pause and still pictures. This part of ISO/113C 11 172 is compatflfle with standard 525- and 625-
`line television formats, and it provides flexibility for use with persona] computer and workstation displays.
`
`iSO/IBC 11172 is primarily applicable to digital storage media supporting a continuous transfer rate up to
`about 1,3 Mbit/s, such as Compact Disc, Digital Audio Tape, and magnetic hard disks. Nevertheless itcan
`be used more widely than this because of the generic approach mken- The storage media maybe directly
`connected to the decoder, or via communications means such as busses,LANs, or telecommunications
`links. This panoflSOfEEC 11172 is intended for non-interlaced video formats having approximamly 238
`lines of 352 pets and picture rates around 24 Hz to 30 Hz.
`
`1.2 Normative references
`
`The following International Standards contain provisions which, through reference in this test, constitute
`provisions of this part of ISOIIEC 11172. At the time of publication, the editionsindicated were valid.
`All standards are subject to revision, and parties to agreements based on this part of ISOIJEC 1 1172 are
`encouraged to investigate the possrbility of applying the most recent editions of rhe- stmdaxds indicated
`below. Members of IEC and ISO maintain registers of currently valid International Standards.
`
`ISOIIEC 11172-11993 Injbrmation technology— Coding oft/noting pictures and associated oudz'ofor digital
`storage media at up to about 1,5 Molt/5 - Part 1: Systems,
`
`.
`
`[SO/113C 11172-321993 Injbmation technology- Coding afflicting pictures and arsociated audio for digital
`storage media at up to about 1,5 Mbit/s- Port 3 Audio.
`
`CCIR Recommendation 601-2 Encoding parameters ofdig ital television for studios.
`
`CCIR Report 624—4 Characteristics of systemsjormonachrom and colour television.
`
`CCIR Recommendation 648 Recording of audio signals.
`
`CCIR Report 955—2 Sound broadcasting by satelliteforportable and mobile receivers, including Annex IV
`Summon) description oon’voncco' Digital System [1.
`
`CCI'IT Recommendation l.17 Pre-emphasis used on Sound-ngramne Circuits.
`
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`ISO/{EC 11172—2: 1993 (E)
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`© SSO/lEC
`
`IEEEDIafI Standard P11 SDIDZ 1990 Specificalion for {he implementation of8.r 8 inverse discrete cosine
`imnmm".
`
`IEC publication 9013:1987 CD Digital Audio System.
`
`
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`2
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`© [SOIIEC
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`ISO/[EC 11172—2: 1993 {E]
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`Section 2: Technical elements
`
`2.1 Definitions
`
`For the purposes of ISOflEC 11172, the following definitions apply. If Specific to a part, this is noted in
`squarebraclzets.
`
`2.1.1 ac coefficient Ivideo]: Any DCT coefficient for which the frequency in one or both dimensions
`is non-zero.
`
`In the case of compressed audio an access unit is an audio access unit.
`2.1.2 access unit lsystcrn]:
`the case of compressed video an access unit is the coded representation of a picture.
`
`In
`
`2.1.3 adaptive segmentation {audio}: A subdivision of the digital representation of an audio signal
`in variable segments of time.
`
`2.1.4 adaptive bit allocation [audio]: The assignment of bits to suhbands in a time and frequency
`varying fashion according to a psychoacousdc model.
`'
`
`2.1.5 adaptive noise allocation [audio]: The assignment of coding noise to frequency bands in a
`time and frequency varying fashion aocording to a psychoacoustic model.
`
`2.1.6 alias [audio]: Mirrored signal component resulting from sub-Nyqnisl sampling.
`
`2.1.7 analysis filter-hank [audio]: Filtetbank in the encoder that transforms a broadband PCM audio
`signal into a set of subsampled subband samples.
`
`2.1.3 audio access unit [audio]: ForeLayers i and I1 an audio access unit is defined as the smallest
`parrot the encoded bitstrcarn which car be decoded by itself, where decoded means “fully rccondructed
`sound'. For Layer [11 an audio across unit is part of the hitstream that is decodable with the use of
`previously acquiredmaih information
`
`2.1.9 audio buffer [audio]: A buffer in the system target decoder for storage of compressed audio data.
`
`2.1.10 audio sequence [audio]: A non-interrupted series of audio frames in which the following
`parameters arenot diangcd:
`- Ii)
`— layer
`- Sampling Frequency
`- PorLayer l and II: Bihate index
`
`2.1.11 backward motion vector [video]: A motion vector that is used for motion compensation
`from a reference picture at a later time in display order.
`
`2.1.12 Bark {audio}: Unit of critical baud rate. The Bark scale is anon-linear mapping of the frequency
`scale over the audio range closely corresponding with the fiequcncy selectivity of the human ear across the
`band.
`
`2.1.13 bidirecfionally predictive-coded picture; B-picture [video]: A picture that is coded
`using motion compensated prediction from a past and'or future reference picture.
`
`2.1.14 bitrate: The rate at which the compressed bitstream is delivered from the storage medium to the
`input of a decoder.
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`2.1.15 block companding [audio]: Normalizing of the digital representation of an audio signal
`within a certain time period.
`'
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`2.1.16 block [video]: An 8-row by lie-column orthogonal block of pels.
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`2.1.17 bound [audio]: The lowest subband in which intensity stereo coding is used.
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`2.1.18 byte aligned: A bit in a coded bitsmam is byte-aligned if its position is amnitipie of S-birs
`from the firstbit in the stream.
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`2.1.19 byte: Sequence of 8-bits.
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`2.1.2.0 channel: A digital medium that stores or transports an ISOIIEC 11 l72 stream.
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`2.1.2} channel [audio]: The left and right channels of a stereo signal
`
`2.1.22 chrominance (component) [video]: A matrix, block or single pel representing one of the
`two colour difference signals related to Ihe primary colours in the manner defined in CCIR Rec 601. The
`symbols umd for the colour difference signals are Cr and Cb.
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`2.1.23 coded audio bitstream [audio]: A coded representation of an audio signal as specified in
`[SOIIEC 11172-3.
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`2.1.24 coded video bitstream [Videolz A coded representation of a series of one or more. pictures as
`specified in this part of {SO/IEC l1 172.
`,
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`2.1.25 coded order [video]: The order in which the pictures are stored and decoded. This order is not
`necessarily the same as the display order.
`
`2.1.26 coded representation: A data clementas represented in its encoded form.
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`2.1.27 coding parameters [video]: The set of user-definable parameters that characterize a coded video
`bitstream. Bitstreams are characterised by coding parameters. Decoders are characterised by the bitstreams
`that they are capable of decoding.
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`2.1.23 component [video]: A matrix, block or single pal. from one of the three matrices (luminance
`and two chromiuancc) that make up a picture,
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`2.1.29 compress-ion: Reduction in the number of hits used to representan item of data.
`
`2.1.30 constant bitrate coded video [video]: A compressed video bitstream with a constant
`averagebitrate.
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`2.1.31 constant bitrate: Operation where the bitrate is constant from start to finish of the compressed
`bitstreain.
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`2.1.32 constrained parameters [video]: The values of the set of coding parameters defined in
`2.4.3.2.
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`2.1.33 constrained system parameter stream (CSPS) [system]: An ISO/[EC 1 1172
`multiplexed stream for which the constraints defined in 2.4.6 of ISOIIEC 11172-1 apply.
`
`2.1.34 CRC: Cyclic redundancy code.
`
`2.1.35 critical band rate [audio]: Psychoacoustic function of frequency. At a given audible
`frequency it is proportional to the number of critical bands below that frequency. _ The units of the critical
`baud rate scale areBadts.
`
`2.1.36 critical band [audio]: Psychoacoustic measure in the spectral domain which corresponds to the
`frequency selectivity of the human car. This selectivity is expressed in Bark.
`
`2.1.37 data element: An item of data as represented before encoding and after decoding.
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`2.1.38 tic-coefficient [video]: The DCT coefficient for which the frequency is zero in both
`dimensions.
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`2.1.39 tic-coded picture; Dupicture {video}: A picture that is coded using only information from
`itself. 0f the DUI" coefficients in the coded representation, only the doecoeificients are present
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`2.1.40 DCT coefficient: The amplitude of a specific cosine basis funcriou.
`
`2.1.41 decoded stream: The decoded reconstruction of a compressed bitstream.
`
`2.1.42 decoder input buffer {video}: The first-in first-out
`buffering verifier.
`
`(FIFO) buffer specified in the video
`
`2.1.43 decoder input rate {video}: The data rate specified in the. video buffering verifirn' and encoded
`in the coded video bitstream.
`
`2.1.44 decoder. An embodiment of a decoding process.
`
`2.1.45 decoding (process): The process defined in ISO/EEC 11172 that reads an input coded hitstream
`and produces decoded pictures or audio samples.
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`2.1.46 decoding time-stamp; DTS [systeml: A field that mayr be present in a packet header that
`indicates the timelhat an access unit is decoded in the system targetdecoder.
`'
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`2.1.47r die-emphasis {audiok Filtering applied to an audio signal after storage or transmission to undo
`a linear distortion due toemphasis
`
`2.1.48 dequantization [video]: The process of rescaling the quantized DCT coefficients after their
`representation in the .hitstream has been decoded and before they are presented to the inverse DCT.
`
`2.1.49 digital storage media; DSM: A digitalstorage or transmission device or system.
`
`2.1.50 discrete cosine transform; DCT [video]: Either the forward discrete cosine transform or the
`inverse discrete cosine transform. The DCT is an invertible, discrete orthogonal transfonnation. The
`inverse DCI‘ is defined in annex A.
`'
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`2.1.51 display order [video]: The order in which the decoded pictures should be displayed. Normally
`this is the same order in which they were promoted at the input of the encoder.
`
`2.1.52 dual channel mode [audio]: A mode, where two audio channels with independent programme
`contents (cg. bilingual) are encoded within one bitstream. The coding process is the same as for the, stereo
`mode.
`
`2.1.53 editing: The process by which one or more compressed bitstreams are manipulated to produce it
`new compressed bitstream. Conforming edited bitstreatns must meet the requirements defined in this part of
`ISO/EEC l1172.
`
`2.1.54 elementary stream [system]: A generic term for one of the coded video, coded audio or other
`coded bitstreams.
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`2.1.55 emphasis [audio]: Filtering applied to an audio signal before storage or transmission to
`improve the signal—to—noise ratio at high frequencies.
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`2.1.56 encoder: An embodiment of an encoding process.
`
`2.1.57 encoding (process): A process, not specified in lSO/IEC 11172. that reads asueam of input
`pictures or audio samples and produces a valid coded bitstream as defined in ISO/113C ll 172.
`
`21.58 entropy coding: Variable length lossless coding of the digital representation of a. signal to
`reduce redundancy.
`
`2.1.59 fast forward piaybaclr Irideol: The process of diSplaying a sequence, or parts of a sequence,
`ofpictures in display-order faster than real-time.
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`2.1.60 F] 1: Fast Fourier Transformation A