ISO/IEC 23002-1:2006
(Main)Information technology — MPEG video technologies — Part 1: Accuracy requirements for implementation of integer-output 8x8 inverse discrete cosine transform
Information technology — MPEG video technologies — Part 1: Accuracy requirements for implementation of integer-output 8x8 inverse discrete cosine transform
A number of image and video coding related standards include a requirement for decoders to implement an integer-output 8x8 inverse discrete cosine transform (IDCT) for the generation of inverse-transformed sample differences with a nominal range from -2B to (2B)-1 for some integer number of bits B, where B is greater than or equal to 8. ISO/IEC 23002-1:2006 specifies conformance requirements for establishing sufficient accuracy in such an integer-output IDCT implementation. It is intended to be suitable for reference to establish partial or complete requirements for IDCT accuracy for conformance to other standards that require IDCT use. The accuracy requirements specified in the main body of ISO/IEC 23002-1:2006 are essentially the same as those previously specified in IEEE 1180-1990 (which has since been withdrawn), in Annex A of ITU-T Rec. H.261, and in Annex A of ITU-T Rec. H.263. These requirements have been specified herein to resolve normative references to IEEE 1180-1990 in MPEG standards after its withdrawal and to provide improved clarity for the specification of IDCT accuracy requirements. An additional requirement on encoded-bitstream intra refresh frequency was also previously specified in IEEE 1180-1990, establishing a requirement of bitstream conformance that each macroblock be intra-coded at least once within each series of 132 times that it is coded in a predicted picture without an intervening intra picture. That additional requirement is not specified in ISO/IEC 23002-1:2006 , in order to confine its scope to the domain of decoder conformance specification. Some allowances for modification of the specified accuracy requirements are made within ISO/IEC 23002-1:2006. Additional accuracy requirements that may be invoked by a referencing specification are specified in Annexes A and B.
Technologies de l'information — Technologies vidéo MPEG — Partie 1: Exigences d'exactitude pour l'implémentation de la transformation cosinus inverse discrète de sortie du nombre entier 8x8
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Standards Content (Sample)
INTERNATIONAL ISO/IEC
STANDARD 23002-1
First edition
2006-12-01
Information technology — MPEG video
technologies —
Part 1:
Accuracy requirements for
implementation of integer-output 8×8
inverse discrete cosine transform
Technologies de l'information — Technologies vidéo MPEG —
Partie 1: Exigences d'exactitude pour l'implémentation de la
transformation cosinus inverse discrète de sortie du nombre entier 8×8
Reference number
ISO/IEC 23002-1:2006(E)
©
ISO/IEC 2006
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ISO/IEC 23002-1:2006(E)
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ISO/IEC 23002-1:2006(E)
Contents Page
Foreword.iv
1 Scope .1
2 Terms and definitions .1
3 Abbreviations and symbols.2
3.1 Abbreviations.2
3.2 Symbols .3
4 Conventions .3
4.1 Arithmetic operators .3
4.2 Logical operators.3
4.3 Relational operators .3
4.4 Bit-wise operators.4
4.5 Assignment operators.4
4.6 Mathematical functions.4
4.7 Range notation.5
4.8 Hexadecimal notation.5
5 IDCT accuracy specification.5
5.1 Ideal real-valued 8x8 forward DCT.5
5.2 Ideal integer-valued 8x8 forward DCT .5
5.3 Ideal real-valued 8x8 inverse DCT.5
5.4 Ideal integer-valued 8x8 inverse DCT.5
5.5 Integer-output IDCT accuracy testing procedure and requirements .6
Annex A (normative) Additional test of near-DC inversion behaviour .9
Annex B (normative) Additional pseudo-random input data tests .10
Bibliography .11
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ISO/IEC 23002-1:2006(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 23002-1 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information Technology,
Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.
ISO/IEC 23002 consists of the following parts, under the general title Information technology — MPEG video
technologies:
⎯ Part 1: Accuracy requirements for implementation of integer-output 8x8 inverse discrete cosine transform
The following part is under preparation:
⎯ Part 3: Auxiliary video data representation
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INTERNATIONAL STANDARD ISO/IEC 23002-1:2006(E)
Information technology — MPEG video technologies —
Part 1:
Accuracy requirements for implementation of integer-output
8x8 inverse discrete cosine transform
1 Scope
A number of image and video coding related standards (see Bibliography) include a requirement for decoders
to implement an integer-output 8x8 inverse discrete cosine transform (IDCT) for the generation of inverse-
B B
transformed sample differences with a nominal range from –2 to (2 )–1 for some integer number of bits B,
where B is greater than or equal to 8. This part of ISO/IEC 23002 specifies conformance requirements for
establishing sufficient accuracy in such an integer-output IDCT implementation. It is intended to be suitable
for reference to establish partial or complete requirements for IDCT accuracy for conformance to other
standards that require IDCT use.
The accuracy requirements specified in the main body of this part of ISO/IEC 23002 are essentially the same
as those previously specified in [7], in Annex A of [1], and in Annex A of [5]. These requirements have been
specified herein to resolve normative references to [7] in MPEG standards after its withdrawal and to provide
improved clarity for the specification of IDCT accuracy requirements.
An additional requirement on encoded-bitstream intra refresh frequency was also previously specified in [7],
establishing a requirement of bitstream conformance that each macroblock be intra-coded at least once within
each series of 132 times that it is coded in a predicted picture without an intervening intra picture. That
additional requirement is not specified in this part of ISO/IEC 23002, in order to confine its scope to the
domain of decoder conformance specification.
Some allowances for modification of the specified accuracy requirements are made within this part of
ISO/IEC 23002. Additional accuracy requirements that may be invoked by a referencing specification are
specified in Annexes A and B.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
array
indexed collection of scalar values
NOTE Square parentheses are used to indicate the indexing of arrays. For example, s[5] denotes the entry at index
5 in the array s.
2.2
discrete cosine transform
DCT
transformation that produces an output matrix of transform coefficients from an input matrix of samples using
some approximation of the process specified in 5.1 or 5.2
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ISO/IEC 23002-1:2006(E)
2.3
forward discrete cosine transform
discrete cosine transform
NOTE The addition of the word “forward” in the term is used when a contrast with the concept of an inverse discrete
cosine transform is intended to be emphasized
2.4
inverse discrete cosine transform
IDCT
transformation that produces an output matrix of samples from an input matrix of transform coefficients using
some approximation of the process specified in 5.3 or 5.4
2.5
matrix
array with a two-dimensional index
NOTE When the matrix represents samples in a spatial sampling grid, the first (left-most) component of the index is
considered to be the vertical component of the index and the second (right-most) component of the index is considered to
be the horizontal component of the index. For example, entry f[3][5] in a matrix f of samples would denote the entry at
vertical position 3 and horizontal position 5. When the matrix represents transform coefficients, the first (left-most)
component of the index is considered to represent a vertical frequency index and the second (right-most) component of
the index is considered to represent a horizontal frequency index. For example, entry F[3][5] in a matrix F of transform
coefficients would denote the entry with vertical frequency index 3 and horizontal frequency index 5.
2.6
sample
entry in a matrix that is the input of a discrete cosine transform or the output of an inverse discrete cosine
transform
NOTE A sample is a scalar value.
2.7
scalar value
integer or real-valued number
2.8
transform coefficient
entry in a matrix that is the output of a forward discrete cosine transform or the input of an inverse discrete
cosine transform
NOTE A transform coefficient is a scalar value.
3 Abbreviations and symbols
For purposes of this document, the following listed abbreviations and symbols apply.
3.1 Abbreviations
AME: absolute mean error
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ISO/IEC 23002-1:2006(E)
DC: referring to the entry in a matrix of transform coefficients associated with the index coordinate pair [0][0].
DCT: discrete cosine transform
IDCT: inverse DCT
MSE: mean squared error
OME: overall mean error
OMSE: overall mean squared error
PAE: peak absolute error
3.2 Symbols
π: Archimedes' constant 3,141 592 653 589 793 238 462 643 …
4 Conventions
4.1 Arithmetic operators
The following arithmetic operators are defined.
+ Addition
– Subtraction (as a two-argument operator) or negation (as a unary prefix operator)
* Multiplication
y
x Exponentiation. Specifies x to the power of y.
x
Division. Specifies division of x by y, producing a real-valued number result.
y
The use of 64-bit floating-point precision for the computation of arithmetic operations is acceptable for
purposes of this part of this International Standard.
When an order of operations is not indicated explicitly by use of parenthesis, the following rules apply:
– exponentiation operations are considered to take place before multiplication and division;
– multiplication and division operations are considered to take place before addition and subtraction;
– multiplication and division operations in sequence are evaluated sequentially from left to right;
– addition and subtraction operations in sequence are evaluated sequentially from left to right.
4.2 Logical operators
A logical operator is defined as follows
x ? y : z If the condition x is TRUE, evaluates to the value of y; otherwise, evaluates to the value of z.
4.3 Relational operators
The following relational operators are defined.
= = Equal to
< Less than
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ISO/IEC 23002-1:2006(E)
> Greater than
<= Less than or equal to
>= Greater than or equal to
The relational operators return the value TRUE if the expressed condition is fulfilled and otherwise return the
value FALSE.
4.4 Bit-wise operators
The following bit-wise operators are defined.
& Bit-wise "and". When operating on integer arguments, operates on two's complement
representations of the integer values. When operating on a binary argument that contains
fewer bits than another argument, the shorter argument is extended by adding more
significant bits equal to 0.
4.5 As
...
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