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1、a Date: 24 September 2008 Origin: International Latest date for receipt of comments: 31 December 2008 Project no.: 2008/00035 Responsible committee: IST/37 Coding of picture, audio, multimedia and hypermedia information Interested committees: Title: Information technology - JPEG XR image coding syst
2、em Part 2: JPEG XR image coding specification Supersession information: If this document is published as a standard, the UK implementation of it will supersede NONE and partially supersede. NONE If you are aware of a current national standard which may be affected, please notify the secretary (conta
3、ct details below). WARNING: THIS IS A DRAFT AND MUST NOT BE REGARDED OR USED AS A BRITISH STANDARD. THIS DRAFT IS NOT CURRENT BEYOND 31 December 2008. This draft is issued to allow comments from interested parties; all comments will be given consideration prior to publication. No acknowledgement wil
4、l normally be sent. See overleaf for information on commenting. No copying is allowed, in any form, without prior written permission from BSI except as permitted under the Copyright, Designs and Patent Act 1988 or for circulation within a nominating organization for briefing purposes. Electronic cir
5、culation is limited to dissemination by e-mail within such an organization by committee members. Further copies of this draft may be purchased from BSI Customer Services, Tel: +44(0) 20 8996 9001 or email . British, International and foreign standards are also available from BSI Customer Services. I
6、nformation on the co-operating organizations represented on the committees referenced above may be obtained from the responsible committee secretary. Cross-references The British Standards which implement International or European publications referred to in this draft may be found via the British S
7、tandards Online Service on the BSI web site http:/. Direct tel: 020 8996 7431 Responsible Committee Secretary: Mrs J M Stride (BSI) E-mail: Draft for Public Comment Head Office 389 Chiswick High Road London W4 4AL Telephone: +44(0)20 8996 9000 Fax: +44(0)20 8996 7001 Form 36 Version 8.0 DPC: 08/301
8、90107 DC Licensed CopyChinese University of Hong Kong, 21/10/2008 08:43, Uncontrolled Copy, (c) BSI b Introduction This draft standard is based on international discussions in which the UK has taken an active part. Your comments on this draft are welcome and will assist in the preparation of the con
9、sequent standard. If no comments are received to the contrary, then the UK will approve this draft. There is a high probability that this text could be adopted by CENELEC as a reference document for harmonization or as a European Standard. Recipients of this draft are requested to comment on the tex
10、t bearing in mind this possibility. UK Vote Please indicate whether you consider the UK should submit a negative (with reasons) or positive vote on this draft. BSI Committee Responsibilities Whether or not the standard is published in its original (international) form, or as a formal British Standar
11、d Implementation, the BSI committees responsibilities are to: - aid enquirers to understand the text; - present to the responsible international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; - monitor related International and European developmen
12、ts and promulgate them in the UK. Submission The guidance given below is intended to ensure that all comments receive efficient and appropriate attention by the responsible BSI committee. Annotated drafts are not acceptable and will be rejected. All comments must be submitted, preferably electronica
13、lly, to the Responsible Committee Secretary at the address given on the front cover. Comments should be compatible with Version 6.0 or Version 97 of Microsoft Word for Windows, if possible; otherwise comments in ASCII text format are acceptable. Any comments not submitted electronically should still
14、 adhere to these format requirements. All comments submitted should be presented as given in the example below. Further information on submitting comments and how to obtain a blank electronic version of a comment form are available from the BSI web site at: http:/ Template for comments and secretari
15、at observations Date: xx/xx/200x Document: ISO/DIS xxxxx 1 2 (3) 4 5 (6) (7) MB Clause No./ Subclause No./ Annex (e.g. 3.1) Paragraph/ Figure/Table/ Note (e.g. Table 1) Type of com- ment Comment (justification for change) by the MB Proposed change by the MB Secretariat observations on each comment s
16、ubmitted 3.1 Definition 1 ed Definition is ambiguous and needs clarifying. Amend to read . so that the mains connector to which no connection . 6.4 Paragraph 2 te The use of the UV photometer as an alternative cannot be supported as serious problems have been encountered in its use in the UK. Delete
17、 reference to UV photometer. Microsoft and MS-DOS are registered trademarks, and Windows is a trademark of Microsoft Corporation. Licensed CopyChinese University of Hong Kong, 21/10/2008 08:43, Uncontrolled Copy, (c) BSI ISO/IEC JTC 1/SC 29/WG1 N 4739 14 September 2008 ISO/IEC JTC 1/SC 29/WG 1 ( and
18、 when a variable is set to the value FALSE, it is set to the value 0. 5.2.3 Relational operators Greater than = Greater than or equal to b Arithmetic right shift of a twos complement integer representation of x by b binary digits, where b is a non-negative integer. Bits shifted into the MSBs as a re
19、sult of the right shift have a value equal to the MSB of x prior to the shift operation. x = x = a is defined as x = (x a) 5.2.6 Precedence order of operators Operators are listed below in descending order of precedence. If several operators appear in the same line, they have equal precedence. When
20、several operators of equal precedence appear at the same level in an expression, evaluation proceeds according to the associativity of the operator either from right to left or from left to right. Licensed CopyChinese University of Hong Kong, 21/10/2008 08:43, Uncontrolled Copy, (c) BSI ISO/IEC FCD
21、29199-2 : 200x (E) 8 Draft ITU-T Rec. T.JXR (200x E) Operators Type of operation Associativity (), , . Expression Left to Right +, Postfix operators Right to Left , ! Unary *, /, %, y x Multiplication Left to Right +, Addition and subtraction Left to Right Arithmetic shift Left to Right. , = Relatio
22、nal Left to Right = =, != Equality test Left to Right The following pseudocode convention specifies evaluation of an “initial statement“ followed by evaluation of a “condition“; if the “condition“ is TRUE, it specifies repeated execution of the “primary statement“ followed by a “subsequent statement
23、“, followed by checking a “condition“, until the “condition“ is no longer TRUE. for (initial statement; condition; subsequent statement) primary statement; The following pseudocode convention specifies that a “statement“ is executed if a “condition“ is TRUE, and that an “alternate statement“ is othe
24、rwise performed. if (condition) statement; else alternative statement; The following pseudocode convention specifies the return of the value of the variable or expression “aExp“ from the pseudocode function or a syntax structure. return aExp; The following pseudocode convention specifies the initial
25、ization of an array. iArr =2, 4, 6, 8; In this example, iArr0 is set to 2, iArr1 is set to 4, iArr2 is set to 6, and iArr3 is set to 8. Licensed CopyChinese University of Hong Kong, 21/10/2008 08:43, Uncontrolled Copy, (c) BSI ISO/IEC FCD 29199-2 : 200x (E) Draft ITU-T Rec. T.JXR (200x E) 9 5.2.8 Ma
26、thematical functions Ceiling(x) Ceiling function. Returns the smallest integer that is greater than or equal to the real- valued argument x. Floor(x) Floor function. Returns the largest integer that is less than or equal to the real-valued argument x. Swap(a, b) Swap(a, b) is defined as follows: t =
27、 a a = b b = t Max(a, b) Maximum of two arguments. if (a = b) Max(a, b) = a else Max(a, b) = b Min(a, b) Minimum of two arguments. if (a = 0 Abs( x ) = x else Abs( x ) = x Sign(x) if x = 0 Sign(x) = 1 else Sign(x) = 1 Round(x) Rounding to integer value. Round(x) = Sign(x) * Floor( Abs(x) + 0.5 ) Sqr
28、t(x) Square root of x Numones(x) Returns the number of bits in x that are set. x is assumed to be a positive integer represented in twos complement arithmetic. a = 0 while (x != 0) a += (x therefore, a separate instance of each global variable exists for the primary image plane and for the alpha ima
29、ge plane (in the case where an alpha image plane is present). In the parsing syntax and pseudocode tables of clause 8, the global variable IsCurrPlaneAlphaFlag is used to indicate which set of global variables are referenced in the table; if IsCurrPlaneAlphaFlag is equal to FALSE, the global variabl
30、es referenced are those of the primary image plane; otherwise (IsCurrPlaneAlphaFlag is equal to TRUE), the global variables referenced are those of the alpha image plane. The scope of local variables is limited to one subclause. They begin with a lower case letter and may include some upper case let
31、ters or numerals and do not include underscore characters, e.g., iValue. Square parentheses are used for the indexing of arrays. Arrays can be either syntax elements or variables. A one- dimensional array is referred to as a list. 5.4.2 Data structure naming conventions An instance of a data structu
32、re is labeled by bold-faced letters. The member variables of a data structure are formatted like global variables. To reference a member variable of a data structure instance, the data structure instances name is associated with the member variable with a period “.“, e.g. AbslevelIndexDCLum.TableInd
33、ex indicates that the member variable TableIndex is part of the data structure instance AbslevelIndexLum. 5.4.3 Syntax structure naming conventions Syntax structure is a term used to refer to a collection of syntax elements. Syntax structures are identified by a name in upper case letters, in which
34、at least one underscore character is included, followed by a pair of parentheses. Within the parentheses, there may be one or more variables. These variables correspond to variables or values that are associated with the pseudocode table for this syntax structure when the syntax structure is invoked
35、 within another syntax structure. 5.4.4 Naming conventions for mnemonic constants Mnemonics are used to refer to constant values taken by syntax elements in the parsing and decoding process. Mnemonics constants are in upper case letters without underscores and may include numbers, e.g., YUV420. The
36、mnemonic constants that are used are defined in Table 2. The mnemonic constant RESERVED is used to specify a value that is reserved for future use. Licensed CopyChinese University of Hong Kong, 21/10/2008 08:43, Uncontrolled Copy, (c) BSI ISO/IEC FCD 29199-2 : 200x (E) 12 Draft ITU-T Rec. T.JXR (200
37、x E) Table 2 Defined mnemonic values Mnemonics Syntax element and Reference YUV444, YUV422, YUV420, YONLY, CMYK, CMYKDIRECT, RGB, RGBE, NCOMPONENT Table 15 for syntax element OUTPUT_CLR_FMT YUV444, YUV422, YUV420, YONLY, YUVK, NCOMPONENT Table 18 for syntax element INTERNAL_CLR_FMT BD1WHITE1, BD8, B
38、D16, BD16S, BD16F, BD32, BD32S, BD5, BD10, BD565, BD1BLACK1 Table 16 for syntax element OUTPUT_BITDEPTH ALL, NOFLEXBITS, NOHIGHPASS, DCONLY Table 19 for syntax element BANDS_PRESENT 5.4.5 Naming conventions for numerical values Integer numbers are expressed as bit patterns, hexadecimal values, or de
39、cimal numbers. Bit patterns and hexadecimal values have both a numerical value and an associated particular length in bits. Hexadecimal notation, indicated by prefixing the hexadecimal number by “0x“, may be used instead of binary notation to denote a bit pattern having a length that is an integer m
40、ultiple of 4. For example, 0x41 represents an eight-bit pattern having only its second bit and its last bit equal to 1. Numerical values that are specified under a “Code“ heading in tables that are referred to as “code tables“ are bit pattern values (specified as a string of digits equal to 0 or 1 i
41、n which the left- most bit is considered the most-significant bit). Other numerical values not prefixed by “0x“ are decimal values. When used in expressions, a hexadecimal value or bit pattern is interpreted as having a value equal to the value of the corresponding bit pattern evaluated as a binary
42、representation of an unsigned integer (i.e. as the value of the number formed by prefixing the bit pattern with a sign bit equal to 0 and interpreting the result as a twos complement representation of an integer value). For example, the hexadecimal value 0xF is equivalent to the 4-bit pattern 1111 a
43、nd is interpreted in expressions as being equal to the decimal number 15. 5.5 Global variables 5.5.1 Image variables The following global variables maintain information relevant to the entire image. OutputWidth: This variable holds the output image width in units of sample columns. OutputHeight: Thi
44、s variable holds the output image height in units of sample rows. InternalWidthi: This variable holds the internal image width of component i. InternalHeighti: This variable holds the internal image height of component i. IsCurrPlaneAlphaFlag: This variable is equal to TRUE if the current plane that
45、 is being parsed or decoded is the alpha image plane; otherwise, this variable is equal to FALSE. It is also used (as specified in subclause 5.4.1) to specify which set of image plane variables, tile variables, and macroblock variables are being referenced. ImagePrimaryixy: For each specific triple
46、(i, x, y), where 0 i 1. If there are N code tables for a syntax element, then there are N1 deltaDisc tables (one deltaDisc table for switching between code tables i and i+1, for i ranging between 0 and N2 inclusive). The AdaptiveVLC data structure associates to DiscrimVal1 the associated variable De
47、ltaTableIndex (Delta2TableIndex for DiscrimVal2); DeltaTableIndex defines which of the N1 deltaDisc tables is in use for the current macroblock. The syntax element itself takes values between 0 and M1, where M represents the number of entries in this syntax elements code table. For each of these val
48、ues, there is defined an associated deltaDisc value. In this way, when the syntax element takes the value iVal, the modification of an AdaptiveVLC data structures discriminants is specified as follows (here, sAdaptVLC is a collective name for all instances of the AdaptiveVLC data structure): sAdaptV
49、LC.DiscrimVal1 += deltaDiscsAdaptVLC.DeltaTableIndexiVal sAdaptVLC.DiscrimVal2 += deltaDiscsAdaptVLC.Delta2TableIndexiVal Tables 3 through 8 specify the set of deltaDisc code tables for adaptive VLC syntax elements. For the syntax element ABS_LEVEL_INDEX (subclause 8.7.14.3), there is one deltaDisc table for switching between Code Tables 0 and 1, as specified in Table 3. Table 3