ITU-T T 801 AMD 2-2005 Information technology C JPEG 2000 image coding system Extensions Amendment 2 Extended capabilities marker segment (Study Group 16)《信息技术-JPEG 2000图像编码系统 扩展修改.pdf

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1、 International Telecommunication Union ITU-T T.801TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 2(05/2005) SERIES T: TERMINALS FOR TELEMATIC SERVICES Information technology JPEG 2000 image coding system: Extensions Amendment 2: Extended capabilities marker segment ITU-T Recommendation T.

2、801 (2002) Amendment 2 ITU-T Rec. T.801 (2002)/Amd.2 (05/2005) i INTERNATIONAL STANDARD ISO/IEC 15444-2 ITU-T RECOMMENDATION T.801 Information technology JPEG 2000 image coding system: Extensions Amendment 2 Extended capabilities marker segment Summary This amendment requires a change to the interpr

3、etation of the Rsiz parameter values within the SIZ marker segment. Specifically, the second most significant bit in the Rsiz field is no longer restricted to be equal to 0. Two new values for the Rsiz field are also defined. Finally, this amendment extends the codestream syntax by providing a new m

4、arker segment, CAP, to signal extended capabilities required to decode the codestream. NOTE ISO/IEC 15444-2 Amendment 1 and Technical Corrigenda 1 and 2 are already integrated in T.801 approved by ITU-T on 2002-08. Source Amendment 2 to ITU-T Recommendation T.801 (2002) was approved on 14 May 2005 b

5、y ITU-T Study Group 16 (2005-2008) under the ITU-T Recommendation A.8 procedure. An identical text is also published as ISO/IEC 15444-2, Amendment 2. ii ITU-T Rec. T.801 (2002)/Amd.2 (05/2005) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the fi

6、eld of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The W

7、orld Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.

8、In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a rec

9、ognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The w

10、ords “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility th

11、at the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommenda

12、tion development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are

13、therefore strongly urged to consult the TSB patent database. ITU 2005 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. T.801 (2002)/Amd.2 (05/2005) iii CONTENTS Page 1) Table A.2 1 2) New clause A.3.1

14、3 2 iv ITU-T Rec. T.801 (2002)/Amd.2 (05/2005) Introduction The JPEG 2000 specification is structured in several parts: Part 1 is defined in ITU-T Rec. T.800 | ISO/IEC 15444-1 (“Core coding system“). Part 2 is defined in ITU-T Rec. T.801 | ISO/IEC 15444-2 (“Extensions“). Part 3 is defined in ITU-T R

15、ec. T.802 | ISO/IEC 15444-3 (“Motion JPEG 2000“). Part 4 is defined in ITU-T Rec. T.803 | ISO/IEC 15444-4 (“Conformance testing“). Part 5 is defined in ITU-T Rec. T.804 | ISO/IEC 15444-5 (“Reference software“). Part 6 is defined in ISO/IEC 15444-6 (“Compound image file format“). Part 7 has been with

16、drawn. Part 8 is defined in ISO/IEC 15444-8 (“Secured JPEG format“). Part 9 is defined in ITU-T Rec. T.808 | ISO/IEC 15444-9 (“Interactivity tools, APIs and protocols“). Part 10 is defined in ISO/IEC 15444-10 (“3-D and floating point data“). Part 11 is defined in ISO/IEC 15444-11 (“Wireless“). Part

17、12 is defined in ISO/IEC 15444-12 (“ISO base media file format“). The need for this amendment arises from a lack of sufficient codespace in the Rsiz capabilities parameter in the SIZ marker segment. The Rsiz parameter contains 16 bits, which are used to signal decoding capabilities required by the e

18、ncoded codestream. According to Table A.10 of ITU-T Rec. T.800 | ISO/IEC 15444-1, the only values used in Part 1 codestreams are: Rsiz = 0000 0000 0000 00xx where: xx = 00 indicates a generic Part 1 codestream xx = 01 indicates a profile 0 codestream xx = 10 indicates a profile 1 codestream In Table

19、 A.2, the first bit of Rsiz is used to indicate the presence of Part 2 features, and the bit values assigned to specific Part 2 capabilities are: Rsiz = 1000 yzzz zzzz zzzz where y = 1 indicates a codestream using Part 2 (precinct-dependent quantization) and bits 6-16 (the z-bits) indicate extension

20、s defined in the Part 2 annexes. In particular, note that there are only 3 unused bits (bits #2, 3, and 4) remaining in the Rsiz field. Signalling Part 2 capabilities requires a full bit per capability because Part 2 features can be selected independently (i.e., in arbitrary combinations) by encoder

21、s, and this situation can be expected to continue for extensions defined in subsequent Parts of the JPEG 2000 family or in future Part 2 amendments. This includes extensions presently under development in JPEG 2000 Parts 8 (JPSEC), 10 (JP3D), and 11 (JPWL), many of which will be used in conjunction

22、with other extensions from different Parts of JPEG 2000. Consequently, the three remaining unused bits in Rsiz are far from sufficient for signalling future JPEG 2000 codestream capabilities. Rather than forcing future JPEG 2000 extensions to invent their own methods of signalling required codestrea

23、m capabilities, this amendment defines a unified, scalable, semantically flexible framework for capabilities signalling that can be used by all future JPEG 2000 Parts and amendments. Moreover, it is fully backwards-compatible with the present capabilities signalling employed in the Rsiz parameter. T

24、he key idea is to define a new variable-length Part 2 marker segment (the CAP marker segment) that indicates the Parts and the specific extended capabilities used to encode the codestream in question. Use of the CAP marker segment is indicated by the second-most-significant bit in the Rsiz parameter

25、. The second bit in the Rsiz parameter can also optionally be used to indicate that a CAP marker segment is used. To a baseline decoder, this will appear as the indication of an unknown capability, which generally prevents the decoder from further decoding the codestream. ISO/IEC 15444-2:2004/Amd.2:

26、2005 (E) ITU-T Rec. T.801 (2002)/Amd.2 (05/2005) 1 INTERNATIONAL STANDARD ITU-T RECOMMENDATION Information technology JPEG 2000 image coding system: Extensions Amendment 2 Extended capabilities marker segment 1) Table A.2 In Table A.2: replace all occurrences of “1000” in the four most significant b

27、its of the index values with “1x00”; and add the following entries immediately preceding the entry describing variable DC offset capability: 0100 0000 0000 00xx Capabilities specified in ITU-T Rec. T.800 | ISO/IEC 15444-1 and at least one extended capability indicated in the CAP marker segment 1100

28、xxxx xxxx xxxx Extended capabilities defined in this Recommendation | International Standard as indicated in this parameter, and at least one other extended capability indicated in the CAP marker segment so that Table A.2 will now read: Value (bits) MSB LSB Capability 0000 0000 0000 0000 Capabilitie

29、s specified in ITU-T Rec. T.800 | ISO/IEC 15444-1 only 1x000 xxxx xxxx xxxx At least one of the extended capabilities specified in this Recommendation | International Standard is present 0100 0000 0000 00xx Capabilities specified in ITU-T Rec. T.800 | ISO/IEC 15444-1 and at least one extended capabi

30、lity indicated in the CAP marker segment 1100 xxxx xxxx xxxx Extended capabilities defined in this Recommendation | International Standard as indicated in this parameter, and at least one other extended capability indicated in the CAP marker segment 1x000 xxx0 xxxx xxx1 Variable DC offset capability

31、 is required to decode this codestreama) b)1x000 xxxx xxxx xx1x Variable scalar quantization capability is required to decode this codestreama)1x000 xxxx xxxx x1xx Trellis coded quantization capability is useful to decode this codestreamc)1x000 xxxx xxxx 1xxx Visual masking capability is useful to d

32、ecode this codestreamc)1x000 xxxx xxx1 xxxx Single sample overlap capability is required to decode this codestreama)1x000 xxxx xx1x xxxx Arbitrary decomposition style capability is required to decode this codestreama)1x000 xxxx x1xx xxxx Arbitrary transformation kernel capability is required to deco

33、de this codestreama)1x000 xxxx 1xxx xxxx Whole sample symmetric transformation kernel capability is required to decode this codestreama)1x000 xxx1 xxxx xxxx Multiple component transformation capability is required to decode this codestreama)1x000 xx1x xxxx xxxx Non-linear point transformation capabi

34、lity is useful to decode this codestreamc)1x000 x1xx xxxx xxxx Arbitrary shaped region of interest capability is required to decode this codestreama)1x000 1xxx xxxx xxxx Precinct-dependent quantization is required to decode this codestreama)All other values reserved a)“Required to decode“ implies th

35、at no useful data or image can be reconstructed without the use of this capability. b)Shall not be used with the multiple component transformation. c)“Useful to decode“ implies that use of this capability would improve the quality of the reconstructed data or image; however, the data or image may be

36、 decoded without its use. ISO/IEC 15444-2:2004/Amd.2:2005 (E) 2 ITU-T Rec. T.801 (2002)/Amd.2 (05/2005) 2) New clause A.3.13 Add the following A.3.13: A.3.13 Extended capabilities (CAP) Function: Signals that extended capabilities were used to create (and are recommended or required to decode) a cod

37、estream. Usage: Optional. If present, must be included anywhere in the main header after the SIZ marker segment. The second-most-significant bit in Rsiz may optionally be set to 1 to indicate the presence of the CAP marker segment. Length: Variable. CAP Lcap Pcap CcapiCcapn Figure A.13 Extended capa

38、bilities syntax CAP: Marker code. Table A.49 shows the size and values of the symbol and parameters for the extended capabilities marker segment. Lcap: Length of the CAP marker segment (not including the marker). Length is given by the following formula: Lcap = 6 + 2n bytes where n is the number of

39、1-bits occurring in Pcap. Pcap: 32-bit field indicating the Parts containing extended capabilities that are used to encode the image. A value of 1 in the kth-most-significant bit of Pcap indicates the use of capabilities from Part k (ISO/IEC 15444-k). The first non-zero bit in Pcap corresponds to th

40、e first Ccapifield (i = 1); the second non-zero bit in Pcap corresponds to the second Ccapifield (i = 2), etc. Table A.50 shows the usage of the Pcap parameter. Ccapi: 16-bit field indicating capabilities specified in Part piwhere bit #pi is the ith non-zero bit in Pcap. If p1= 2, the bits in Ccap1

41、shall indicate capabilities defined in Part 2 amendments; the MSB of Rsiz may be set to the value 1 in this case. For other Parts, the bits in Ccapi may be used to indicate capabilities defined in Part pi. The precise meaning of the bits in Ccapi shall be specified in Part pi(ISO/IEC 15444-pi). Tabl

42、e A.49 Extended capabilities parameter values Parameter Size (bits) Value CAP 16 0xFF50 Lcap 16 80-560 Pcap 32 See Table A.50 Ccapi16 Value and meaning specified in ISO/IEC 15444-k, where the ith non-zero bit in Pcap occurs in its kth most significant bit Table A.50 Part parameter values for the Pca

43、p parameter Values (bits) MSB LSB Part parameter 1xxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx Extended capabilities from ISO/IEC 15444-1 were used to encode the image x1xx xxxx xxxx xxxx xxxx xxxx xxxx xxxx Extended capabilities from ISO/IEC 15444-2 were used to encode the image xxxx xxxx xxxx xxxx xxxx

44、xxxx xxxx xxx1 Extended capabilities from ISO/IEC 15444-32 were used to encode the image ISO/IEC 15444-2:2004/Amd.2:2005 (E) ITU-T Rec. T.801 (2002)/Amd.2 (05/2005) 3 Guidance on usage (informative): Encoders that wish to induce baseline JPEG-2000 (Part 1) decoders to attempt best-effort decoding of

45、 a codestream containing non-Part 1 features may elect not to use the second-most-significant bit in Rsiz to signal the presence of the CAP marker segment. According to clause A.1 of ITU-T Rec. T.800 | ISO/IEC 15444-1, decoder implementations are supposed to deal with unrecognized marker segments by

46、 using the length parameter to discard the marker segment. Because of this possibility, decoders that recognize any of the capabilities that would be indicated in a CAP marker segment may choose to parse for the CAP marker segment in all JPEG 2000 codestreams, regardless of the value of the second R

47、siz bit. Encoders should facilitate this parsing by placing the CAP marker segment as close as possible to the front of the main header. It is recommended that the CAP marker segment always appear before any other marker segments that support extended capabilities indicated in the CAP marker segment

48、, so that such capabilities will have been indicated to the decoder prior to encountering any related marker segments. Encoders that wish to deter baseline decoders from attempting to decode a codestream that truly requires capabilities indicated in the CAP marker segment should set the second Rsiz

49、bit to 1. Printed in Switzerland Geneva, 2005 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of television, sound programme and other multi