1 2 3 4 5 6 7 8 9 Digital Imaging and Communications in Medicine (DICOM) 10 11 Supplement 180: MPEG-4 AVC/H.264 Transfer Syntax 12 13 14 15 16 17 18 19 20 21 22 DICOM Standards Committee, Working Group 13 Visible Light 23 1300 N. 17th Street Suite 1752 24 Rosslyn, Virginia 22209 USA 25 26 VERSION: 27 Developed in accordance with work item 2014-04-A. 28 29 05, Draft for Letter Ballot 30 Table of Contents 31 Scope and Field of Application ....................................................................................................................... 3 Changes to NEMA Standards Publication PS 3.5 .......................................................................................... 4 Section 2 Normative references ............................................................................................................... 5 8.2.X MPEG-4 AVC/H.264 High Profile / Level 4.2 Video Compression ................................. 6 8.2.Y MPEG-4 AVC/H.264 Stereo High Profile / Level 4.2 Video Compression ..................... 7 10.X TRANSFER SYNTAX FOR MPEG-4 AVC/H.264 HIP@LEVEL4.2 IMAGE COMPRESSION 8 10.Y TRANSFER SYNTAX FOR MPEG-4 AVC/H.264 STEREO HIGH PROFILE / LEVEL 4.2 IMAGE COMPRESSION .......................................................................................................................... 8 Annex A (Normative) Transfer Syntax Specifications .................................................................................... 8 A.4.X MPEG-4 AVC/H.264 HIP@LEVEL4.2 VIDEO COMPRESSION ............................................. 8 Annex A (Normative) Transfer Syntax Specifications .................................................................................... 9 A.4.Y MPEG-4 AVC/H.264 STEREO HIGH PROFILE /LEVEL 4.2 VIDEO COMPRESSION .......... 9 Changes to NEMA Standards Publication PS 3.6 ........................................................................................ 10 Changes to NEMA Standards Publication PS 3.11 ...................................................................................... 12 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 Scope and Field of Application 47 48 49 This supplement describes two new Transfer Syntaxes to embed MPEG-4 Advanced Video Coding (AVC) / H.264 High Profile / Level 4.2 (HiP@Level4.2) and H.264 Stereo High Profile /Level 4.2 encoded pixel data in DICOM. It does not introduce any new SOP Classes or IODs. 50 51 52 53 54 55 56 57 Transfer Syntax MPEG-4 AVC/H.264 High Profile / Level 4.2 (HiP@Level4.2) will perform consistent with the ITU-T H.264 HiP@Level4.2. This will enable the storage of video files with a resolution of 1920x1080 at 50Hz/60Hz. 58 This proposed supplement includes Addenda to existing Parts of DICOM: Transfer Syntax MPEG-4 AVC/H.264 Stereo High Profile /Level 4.2 will perform consistent with the ITU-T H.264 Stereo High Profile at Level 4.2. This will enable the storage of video files where higher compression can be achieved due to inter-view prediction. An example of the use would be in binocular operational microscopy. 59 - PS 3.5 Addendum: Data Structures and Encoding 60 - PS 3.6 Addendum: Data Dictionary 61 - PS 3.11 Addendum Media Storage Application Profiles 62 63 In the years since the DICOM Committee WG13 approved the new MPEG-4 AVC/H.264 Transfer Syntax with supplement 149, the capabilities of video recorders and video players have advanced considerably. 64 65 66 67 Support is required in DICOM for 1080P 50/60 Hz as defined by MPEG-4 AVC / H.264 Level 4.2. Considerable space savings can be achieved when storing stereo recordings in Stereo High Profile format. These two new transfer syntax will help to support advance technologies with an updated set of higher resolution, frame rates and compression capabilities. 68 69 70 71 72 73 74 75 76 Changes to NEMA Standards Publication PS 3.5 77 Digital Imaging and Communications in Medicine (DICOM) 78 Part 5: Data Structures and Encoding 79 80 Add references to section 2: Section 2 81 Normative references 82 … 83 ISO/IS 14495-1 Lossless and near-lossless coding of continuous tone still images (JPEG-LS) 84 ISO/IEC 14496-10:2012 Information technology – Coding of audio-visual objects – Part 10: Advanced Video Coding 86 ISO/IEC 15444-1 JPEG 2000 Image Coding System 87 … 85 88 89 Add MPEG-4 AVC/H.264 High Profile / Level 4.2 video compression to Section 8. 90 8.2.X 91 92 93 DICOM provides a mechanism for supporting the use of MPEG-4 AVC/H.264 Image Compression through the Encapsulated Format (see PS 3.3). Annex A defines a Transfer Syntax that references the MPEG-4 AVC/H.264 Standard. 94 95 96 97 Note: MPEG-4 AVC/H.264 High Profile / Level 4.2 Video Compression MPEG-4 AVC/H.264 compression @ High Profile compression is inherently lossy. The context where the usage of lossy compression of medical images is clinically acceptable is beyond the scope of the DICOM Standard. The policies associated with the selection of appropriate compression parameters (e.g. compression ratio) for MPEG-4 AVC/H.264 HiP@Level4.2 are also beyond the scope of this standard. 98 99 100 101 102 103 104 105 106 The use of the DICOM Encapsulated Format to support MPEG-4 AVC/H.264 compressed pixel data requires that the Data Elements which are related to the Pixel Data encoding (e.g. Photometric Interpretation, Samples per Pixel, Planar Configuration, Bits Allocated, Bits Stored, High Bit, Pixel Representation, Rows, Columns, etc.) shall contain values that are consistent with the characteristics of the compressed data stream, with some specific exceptions noted here. The Pixel Data characteristics included in the MPEG-4 AVC/H.264 bit stream shall be used to decode the compressed data stream. Notes: 107 108 109 110 111 1. These requirements are specified in terms of consistency with what is encapsulated, rather than in terms of the uncompressed pixel data from which the compressed data stream may have been derived. 2. When decompressing, should the characteristics explicitly specified in the compressed data stream be inconsistent with those specified in the DICOM Data Elements, those explicitly specified in the compressed data stream should be used to control the decompression. The DICOM data elements, if inconsistent, can be regarded as suggestions as to the form in which an uncompressed data set might be encoded. 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 The requirements are: Planar Configuration (0028,0006) shall be 0 Samples per Pixel (0028,0002) shall be 3 Photometric Interpretation (0028,0004) shall be YBR_PARTIAL_420 Bits Allocated (0028,0100) shall be 8 Bits Stored (0028,0101) shall be 8 High Bit (0028,0102) shall be 7 Pixel Representation (0028,0103) shall be 0 The value of MPEG-4 AVC/H.264 sample aspect_ratio_idc shall be 1 in the encapsulated MPEG-4 AVC/H.264 bit stream if aspect_ratio_info_present_flag is 1. Pixel Aspect Ratio (0028,0034) shall be absent. This corresponds to a 'Sampling Aspect Ratio' (SAR) of 1:1. The possible values for Rows (0028,0010), Columns (0028,0011), Cine Rate (0018,0040) , and Frame Time (0018,1063) or Frame Time Vector (0018,1065) depend on the used transfer syntax. o For MPEG-4 AVC/H.264 High Profile / Level 4.2 transfer syntax, the values for these data elements shall be compliant with the High Profile / Level 4.2 of the MPEG-4 AVC/H.264 standard (ISO/IEC 14496-10:2012) and restricted to a square pixel aspect ratio. 130 131 132 133 134 135 Notes: 1. The value of Planar Configuration (0028,0006) is irrelevant since the manner of encoding components is specified in the MPEG-4 AVC/H.264 standard, hence it is set to 0. 2. The frame rate of the acquiring camera for ’30 Hz HD’ MPEG-4 AVC/H.264 may be either 30 or 30/1.001 (approximately 29.97) frames/sec. Similarly, the frame rate in the case of 60 Hz may be either 60 or 60/1.001 (approximately 59.94) frames/sec. This may lead to small inconsistencies between the video timebase and real time. The relationship between frame rate and frame time is shown in Table 8-x. 3. The Frame Time (0018,1063) may be calculated from the frame rate of the acquiring camera. A frame rate of 29.97 frames per second corresponds to a frame time of 33.367 ms. 4. The value of chroma_format for this profile and level is defined by MPEG as 4:2:0. 5. SEI (Supplemental Enhancement Information) elements called frame packing arrangement are used to indicate stereo formats within the video data. 136 137 138 139 140 141 142 143 144 145 Table 8-x MPEG-4 AVC/H.264 High Profile / Level 4.2 IMAGE TRANSFER SYNTAX FRAME RATE ATTRIBUTES Video Type Frame Rate (see Note 2) Frame Time (see Note 3) 30 Hz HD 30 33.33 ms 25 Hz HD 25 40.0 ms 60 Hz HD 60 16.17 ms 50 Hz HD 50 20.00 ms 146 147 148 149 150 151 152 One fragment shall contain the whole MPEG-4 AVC/H.264 bit stream. Note: If a video stream exceeds the maximum length of one fragment (approximately 4 GB), it may be sent as multiple SOP Instances, but each SOP Instance will contain an independent and playable bit stream, and not depend on the encoded bit stream in other (previous) instances. The manner in which such separate instances are related is not specified in the standard, but mechanisms such as grouping into the same Series, and references to earlier instances using Referenced Image Sequence may be used. 153 154 155 156 157 The container format for the video bitstream shall be MPEG-2 Transport Stream, a.k.a. MPEG-TS (see [ISO/IEC 13818-1]) or ISO base media file format / MP4 (see [ISO/IEC 14496-12] and [ISO/IEC 1449614]). The allowed audio formats are as defined for MPEG-4 AVC/H.264 High Profile Level 4.1. (see Section 8.2.7). 158 159 Add MPEG-4 AVC/H.264 Stereo High Profile / Level 4.2 video compression to Section 8. 160 8.2.Y 161 162 163 DICOM provides a mechanism for supporting the use of MPEG-4 AVC/H.264 Image Compression through the Encapsulated Format (see PS 3.3). Annex A defines a Transfer Syntax that references the MPEG-4 AVC/H.264 Standard. 164 165 166 167 MPEG-4 AVC/H.264 Stereo High Profile makes use of the Level table A-1 of the MPEG-4 specification to set through-put limits. The properties required by the MPEG-4 AVC/H.264 Stereo High Profile Compression are identical to the properties defined in chapter 8.2.X MPEG-4 AVC/H.264 High Profile / Level 4.2. 168 169 170 171 The container format for the video bitstream shall be MPEG-2 Transport Stream, a.k.a. MPEG-TS (see [ISO/IEC 13818-1]) or ISO base media file format / MP4 (see [ISO/IEC 14496-12] and [ISO/IEC 1449614]). The allowed audio formats are as defined for MPEG-4 AVC/H.264 High Profile Level 4.1. (see Section 8.2.7). 172 173 174 MPEG-4 AVC/H.264 Stereo High Profile / Level 4.2 Video Compression 175 176 Add TRANSFER SYNTAX FOR MPEG-4 AVC/H.264 High Profile / Level 4.2 COMPRESSION to Section 10. 177 178 10.X TRANSFER SYNTAX FOR MPEG-4 AVC/H.264 HIP@LEVEL4.2 IMAGE COMPRESSION 179 180 181 One Transfer Syntax is specified for MPEG-4 AVC/H.264 High Profile / Level 4.2 Image Compression. Transfer Syntax MPEG-4 AVC/H.264 High Profile / Level 4.2 corresponds to the ITU-T H.264 standard’s profile and level specifications. 182 183 184 185 Add TRANSFER SYNTAX FOR MPEG-4 AVC/H.264 Stereo High Profile / Level 4.2 COMPRESSION to Section 10. 186 187 10.Y TRANSFER SYNTAX FOR MPEG-4 AVC/H.264 STEREO HIGH PROFILE / LEVEL 4.2 IMAGE COMPRESSION 188 189 190 One Transfer Syntax is specified for MPEG-4 AVC/H.264 Stereo High Profile up to Level 4.2 Image Compression. Transfer Syntax MPEG-4 AVC/H.264 Stereo High Profile corresponds to the ITU-T H.264 standard’s profile and level specifications. 191 192 Add MPEG-4 AVC/H.264 High Profile / Level 4.2 requirements to Annex A. Annex A (Normative) Transfer Syntax Specifications 193 194 195 196 A.4.X 197 198 199 200 The International Standards Organization ISO/IEC MPEG4 has developed an International Standard, ISO/IEC 14496-10 (MPEG-4 Part 10), for the video compression of generic coding of moving pictures and associated audio information. This standard is jointly maintained and has identical technical content as the ITU-T H.264 standard. 201 202 A DICOM Transfer Syntax for MPEG-4 AVC/H.264 Image Compression shall be identified by a UID value of either: 203 204 MPEG-4 AVC/H.264 HIP@LEVEL4.2 VIDEO COMPRESSION 1.2.840.10008.1.2.4.XXX corresponding to the MPEG-4 AVC/H.264 High Profile / Level 4.2 of the ITUT H.264 Video standard 205 206 Add MPEG-4 AVC/H.264 Stereo High Profile / Level 4.2 requirements to Annex A. Annex A (Normative) Transfer Syntax Specifications 207 208 209 210 A.4.Y 211 212 213 214 The International Standards Organization ISO/IEC MPEG4 has developed an International Standard, ISO/IEC 14496-10 (MPEG-4 Part 10), for the video compression of generic coding of moving pictures and associated audio information. This standard is jointly maintained and has identical technical content as the ITU-T H.264 standard. 215 216 A DICOM Transfer Syntax for MPEG-4 AVC/H.264 Image Compression shall be identified by a UID value of either: 217 218 MPEG-4 AVC/H.264 STEREO HIGH PROFILE /LEVEL 4.2 VIDEO COMPRESSION 1.2.840.10008.1.2.4.YYY corresponding to the MPEG-4 AVC/H.264 Stereo High Profile up to Level 4.2 of the ITU-T H.264 Video standard 219 220 221 222 223 224 225 226 Changes to NEMA Standards Publication PS 3.6 227 Digital Imaging and Communications in Medicine (DICOM) 228 Part 6: Data Dictionary 229 230 Add new UID to Annex A. 231 UID Value 232 233 UID Name UID Type Part 1.2.840.10008.1.2.4.XXX MPEG-4 AVC/H.264 High Profile / Level 4.2 Transfer Syntax PS 3.5 1.2.840.10008.1.2.4.YYY Transfer Syntax PS 3.5 MPEG-4 AVC/H.264 Stereo High Profile / Level 4.2 234 235 236 237 238 239 Changes to NEMA Standards Publication PS 3.11 240 Digital Imaging and Communications in Medicine (DICOM) 241 Part 11: Media Storage Application Profiles 242 243 244 PS 3.11: Update Blu-ray media profiles to include MPEG-4 AVC/H.264 Level 4.2. transfer syntaxes 245 248 M General Purpose BD With Compression Interchange Profiles (Normative) 249 M.1 Profile Identification 250 251 252 253 254 255 256 This Annex defines an Application Profile Class potentially inclusive of all defined Media Storage SOP Classes. This class is intended to be used for the interchange of Composite SOP Instances via BD media for general-purpose applications. Objects from multiple modalities may be included on the same media. Images may be compressed with or without loss using either JPEG or JPEG 2000. And multi-frame images and video may be compressed with MPEG2 Main Profile / Main Level or MPEG2 Main Profile / High Level or MPEG-4 AVC/H.264 High Profile / Level 4.1 or MPEG-4 AVC/H.264 BD-compatible High Profile / Level 4.1 or MPEG-4 AVC/H.264 High Profile / Level 4.2 or MPEG-4 AVC/H.264 Stereo High Profile / Level 4.2:all readers shall support compression. 257 A detailed list of the Media Storage SOP Classes that may be supported is defined in PS3.4. 246 247 258 259 Table M.1-1. STD-GEN-BD and STD-GEN-SEC-BD Profiles Application Profile Identifier Description General Purpose BD Interchange with JPEG STD-GEN-BD-JPEG Handles interchange of Composite SOP Instances such as Images (optionally compressed with either lossless or lossy JPEG), Structured Reports, Presentation States and Waveforms. General Purpose BD Interchange with JPEG 2000 STD-GEN-BD-J2K Handles interchange of Composite SOP Instances such as Images (optionally compressed with either lossless or lossy JPEG 2000), Structured Reports, Presentation States and Waveforms. General Purpose BD Interchange with MPEG2 MP@ML STD-GEN-BD-MPEG2-MPML Handles interchange of multi-frame images and video using MPEG2 MP@ML compression. General Purpose BD Interchange with MPEG2 MP@HL STD-GEN-BD-MPEG2-MPHL Handles interchange of multi-frame images and video using MPEG2 MP@HL compression. General Purpose BD Interchange with MPEG-4 AVC/H.264 HiP@Level4.1 STD-GEN-BD-MPEG4-HPLV41 Handles interchange of multi-frame images and video using MPEG-4 AVC/H.264 HiP@Level4.1 compression. General Purpose BD Interchange with MPEG-4 AVC/H.264 BD-Compatible STD-GEN-BD-MPEG4-HPLV41BD Handles interchange of multi-frame images and video using MPEG-4 AVC/H.264 BD- Application Profile Identifier HiP@Level4.1 Description compatible HiP@Level4.1 compression. General Purpose BD Interchange with MPEG-4 AVC/H.264 HiP@Level4.2 STD-GEN-BD-MPEG4-HPLV42 Handles interchange of multi-frame images and video using MPEG-4 AVC/H.264 HiP@Level4.2 compression. General Purpose BD Interchange with MPEG-4 AVC/H.264 Stereo HiP@Level4.2 STD-GEN-BD-MPEG4-SHPLV42 Handles interchange of multi-frame images and video using MPEG-4 AVC/H.264 Stereo High Profile / Level4.2 compression. General Purpose Secure BD Interchange with JPEG STD-GEN-SEC-BD-JPEG Handles interchange of Composite SOP Instances such as Images (optionally compressed with either lossless or lossy JPEG), Structured Reports, Presentation States and Waveforms. Offers confidentiality, integrity and, depending on the File-set creator's choice, data origin authentication. General Purpose Secure BD Interchange with JPEG 2000 STD-GEN-SEC-BD-J2K Handles interchange of Composite SOP Instances such as Images (optionally compressed with either lossless or lossy JPEG 2000), Structured Reports, Presentation States and Waveforms. Offers confidentiality, integrity and, depending on the File-set creator's choice, data origin authentication. General Purpose Secure BD Interchange with MPEG2 MP@ML STD-GEN-SEC-BD-MPEG2-MPML Handles interchange of multi-frame images and video using MPEG2 MP@ML compression. Offers confidentiality, integrity and, depending on the File-set creator's choice, data origin authentication. General Purpose Secure BD Interchange with MPEG2 MP@HL STD-GEN-SEC-BD-MPEG2-MPHL Handles interchange of multi-frame images and video using MPEG2 MP@HL compression. Offers confidentiality, integrity and, depending on the File-set creator's choice, data origin authentication. General Purpose Secure BD Interchange with MPEG-4 AVC/H.264 HiP@Level4.1 STD-GEN-SEC-BD-MPEG4-HPLV41 Handles interchange of multi-frame images and video using MPEG-4 AVC/H.264 HiP@Level4.1 compression. Offers confidentiality, integrity and, depending on the File-set creator's choice, data origin authentication. General Purpose Secure BD Interchange with MPEG-4 AVC/H.264 BD-compatible HiP@Level4.1 STD-GEN-SEC-BD-MPEG4-HPLV41BD Handles interchange of multi-frame images and video using MPEG-4 AVC/H.264 BDcompatible HiP@Level4.1 compression. Offers confidentiality, integrity and, depending on the File-set creator's choice, data origin authentication. General Purpose Secure BD Interchange STD-GEN-SEC-BD-MPEG4-HPLV42 Handles interchange of multi-frame Application Profile Identifier Description with MPEG-4 AVC/H.264 HiP@Level4.2 images and video using MPEG-4 AVC/H.264 HiP@Level4.2 compression. Offers confidentiality, integrity and, depending on the File-set creator's choice, data origin authentication. General Purpose Secure BD Interchange STD-GEN-SEC-BD-MPEG4-SHPLV42 with MPEG-4 AVC/H.264 BD-compatible High Profile / Level4.12 Handles interchange of multi-frame images and video using MPEG-4 AVC/H.264 High Profile / Level4.2 compression. Offers confidentiality, integrity and, depending on the File-set creator's choice, data origin authentication. 260 261 ... 262 263 264 Table M.3-1. STD-GEN-BD and STD-GEN-SEC-BD SOP Classes and Transfer Syntaxes Information Object Definition Basic Directory SOP Class UID Transfer Syntax and UID 1.2.840.10008.1.3.10 Explicit VR Little Endian Uncompressed FSC Requirement FSR Requirement FSU Requirement Mandatory Mandatory Mandatory Defined in Conformance Statement Mandatory for all SOP Classes defined in Conformance Statement Defined in Conformance Statement Defined in Conformance Statement Mandatory for JPEG profiles for all SOP Classes defined in Conformance Statement Defined in Conformance Statement Defined in Conformance Statement Mandatory for JPEG profiles for all SOP Classes defined in Conformance Statement Defined in Conformance Statement Defined in Conformance Statement Mandatory for JPEG profiles for all SOP Classes defined in Conformance Defined in Conformance Statement 1.2.840.10008.1.2.1 Composite IODs See PS3.4 for which a Media Storage SOP Class is defined in PS3.4 Explicit VR Little Endian Uncompressed Composite IODs See PS3.4 for which a Media Storage SOP Class is defined in PS3.4 JPEG Lossless Process 14 (selection value 1) Composite IODs See PS3.4 for which a Media Storage SOP Class is defined in PS3.4 JPEG Lossy, Baseline Sequential with Huffman Coding (Process 1) Composite IODs See PS3.4 for which a Media Storage SOP Class is defined in PS3.4 JPEG Extended (Process 2 & 4): 1.2.840.10008.1.2.1 1.2.840.10008.1.2.4.70 1.2.840.10008.1.2.4.50 Default Transfer Syntax for Lossy JPEG 12 Bit Image Information Object Definition SOP Class UID Transfer Syntax and UID FSC Requirement Compression (Process 4 only) FSR Requirement FSU Requirement Statement 1.2.840.10008.1.2.4.51 Composite IODs See PS3.4 for which a Media Storage SOP Class is defined in PS3.4 JPEG 2000 Image Compression (Lossless Only) Composite IODs See PS3.4 for which a Media Storage SOP Class is defined in PS3.4 JPEG 2000 Image Compression See PS3.4 Multi-frame Composite IODs for which a Media Storage SOP Class is defined in PS3.4 MPEG2 Main Profile @ Main Defined in Level Conformance Statement 1.2.840.10008.1.2.4.100 Mandatory for all SOP Classes defined in Conformance Statement Defined in Conformance Statement See PS3.4 Multi-frame Composite IODs for which a Media Storage SOP Class is defined in PS3.4 MPEG2 Main Profile @ High Defined in Level Conformance Statement 1.2.840.10008.1.2.4.101 Mandatory for all SOP Classes defined in Conformance Statement Defined in Conformance Statement See PS3.4 Multi-frame Composite IODs for which a Media Storage SOP Class is defined in PS3.4 MPEG-4 AVC/H.264 High Profile / Level 4.1 Defined in Conformance Statement Mandatory for all SOP Classes defined in Conformance Statement Defined in Conformance Statement See PS3.4 Multi-frame Composite IODs for which a Media Storage SOP Class is defined in PS3.4 MPEG-4 AVC/H.264 BDcompatible High Profile / Level 4.1 Defined in Conformance Statement Mandatory for all SOP Classes defined in Conformance Statement Defined in Conformance Statement Multi-frame See PS3.4 Composite IODs for which a Media Storage SOP Class is defined in PS3.4 MPEG-4 AVC/H.264 High Profile / Level 4.2 Defined in Conformance Statement Mandatory for all Defined in SOP Classes Conformance defined in Statement Conformance Statement Defined in Conformance Statement Mandatory for J2K Defined in profiles for all Conformance SOP Classes Statement defined in Conformance Statement Defined in Conformance Statement Mandatory for J2K Defined in profiles for all Conformance SOP Classes Statement defined in Conformance Statement 1.2.840.10008.1.2.4.90 1.2.840.10008.1.2.4.91 1.2.840.10008.1.2.4.102 1.2.840.10008.1.2.4.103 1.2.840.10008.1.2.4.XXX Information Object Definition SOP Class UID Multi-frame See PS3.4 Composite IODs for which a Media Storage SOP Class is defined in PS3.4 265 Transfer Syntax and UID FSC Requirement MPEG-4 AVC/H.264 Stereo Defined in High Profile / Level 4.2 Conformance Statement 1.2.840.10008.1.2.4.YYY FSR Requirement FSU Requirement Mandatory for all Defined in SOP Classes Conformance defined in Statement Conformance Statement