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DICOM PS3.5 2020a - Data Structures and Encoding​ Page 81​

Table 8-8. MPEG-4 AVC/H.264 High Profile / Level 4.2 Image Transfer Syntax Stereo Attributes​

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 In-​ stances, 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.​

ThecontainerformatforthevideobitstreamshallbeMPEG-2TransportStream,a.k.a.MPEG-TS(see[ISO/IEC13818-1])orMPEG-​ 4, a.k.a. MP4 container (see [ISO/IEC 14496-12] and [ISO/IEC 14496-14]). The PTS/DTS of the transport stream shall be used in​ the MPEG coding.​

Any audio components included in the data container shall follow the constraints detailed in Section 8.2.12 Constraints for Audio Data​

Integration in AVC and HEVC Compressed Bit Streams.​

8.2.9 MPEG-4 AVC/H.264 Stereo High Profile / Level 4.2 Video Compression​

DICOM provides a mechanism for supporting the use of MPEG-4 AVC/H.264 Image Compression through the Encapsulated Format​ (see PS3.3). Annex A defines a Transfer Syntax that references the MPEG-4 AVC/H.264 Standard.​

MPEG-4 AVC/H.264 Stereo High Profile can achieve better compression by additionally making use of prediction between the base​ and dependent stereoscopic views. The base view frames make use of intra and inter prediction as in MPEG-4 AVC/H.264 High​ Profile. This makes it possible for decoders which do not know how to decode the stereoscopic data to decode only the base view.​ The dependent view is encoded to make use of redundancy due to prediction based upon similarities between the base and the de-​ pendent views.​

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​ propertiesrequiredbytheMPEG-4AVC/H.264StereoHighProfileCompressionareidenticaltothepropertiesdefinedinSection8.2.8,​ except that Stereo Pairs Present (0022,0028) shall always be YES.​

ThecontainerformatforthevideobitstreamshallbeMPEG-2TransportStream,a.k.a.MPEG-TS(see[ISO/IEC13818-1])orMPEG-​ 4, a.k.a. MP4 container (see [ISO/IEC 14496-12] and [ISO/IEC 14496-14]). The PTS/DTS of the transport stream shall be used in​ the MPEG coding.​

Any audio components included in the data container shall follow the constraints detailed in Section 8.2.12 Constraints for Audio Data​

Integration in AVC and HEVC Compressed Bit Streams.​

8.2.10 HEVC/H.265 Main Profile / Level 5.1 Video Compression​

HEVC/H.265MainProfile/Level5.1Maintierisdesignedforthecompressionof4:2:0videoformatsupto4kat60framespersecond​ with a bit depth of 8 bits. DICOM provides a mechanism for supporting the use of HEVC/H.265 Image Compression through the En-​ capsulated Format (see PS3.3). Annex A defines a Transfer Syntax that references the HEVC/H.265 Standard.​

The use of the DICOM Encapsulated Format to support HEVC/H.265 compressed pixel data requires that the Data Elements that​ 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 HEVC/H.265 bit​ stream shall be used to decode the compressed data stream.​

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Note​

1.​These requirements are specified in terms of consistency with what is encapsulated, rather than in terms of the uncom-​ pressed pixel data from which the compressed data stream may have been derived.​

2.​Whendecompressing,shouldthecharacteristicsexplicitlyspecifiedinthecompresseddatastreambeinconsistentwith​ 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, subject to the general and IOD-specific rules for uncom-​ pressed Photometric Interpretation and Planar Configuration, which may require that decompressed data be converted​ to one of the permitted forms.​

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 HEVC/H.265 sample aspect_ratio_idc shall be 1 in the encapsulated HEVC/H.265 bit stream if aspect_ra-​ tio_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 values for Rows (0028,0010), Columns (0028,0011), Cine Rate (0018,0040) and Frame Time (0018,1063) or Frame Time​ Vector(0018,1065)shallbecompliantwiththeMainProfile/Level5.1oftheHEVC/H.265standard[ISO/IEC23008-2]andrestricted​ to a square pixel aspect ratio.​

Note​

1.​The value of Planar Configuration (0028,0006) is irrelevant since the manner of encoding components is specified in​ the HEVC/H.265 standard, hence it is set to 0.​

2.​The limitation on rows and columns are to maximize interoperability between software environments and commonly​ available hardware HEVC/H.265 encoder/decoder implementations. Source pictures that have a lower value should be​ re-formatted by scaling and/or pixel padding prior to HEVC/H.265 encoding.​

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_idc for this profile and level is equal to 1, indicating the usage of 4:2:0 content.​

The encapsulated pixel data stream may be segmented into more than one fragment.​

Note​

The recipient is expected to concatenate the fragments while decoding them. This allows for essentially unlimited length​ streams; the only limit imposed is the maximum size of frames (0028,0008) which is 2^31-1.​

ThecontainerformatforthevideobitstreamshallbeMPEG-2TransportStream,a.k.a.MPEG-TS(see[ISO/IEC13818-1])orMPEG-​ 4, a.k.a. MP4 container (see [ISO/IEC 14496-12] and [ISO/IEC 14496-14]). The PTS/DTS of the transport stream shall be used in​ the MPEG coding.​

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Any audio components included in the data container shall follow the constraints detailed in Section 8.2.12 Constraints for Audio Data​

Integration in AVC and HEVC Compressed Bit Streams.​

8.2.11 HEVC/H.265 Main 10 Profile / Level 5.1 Video Compression​

HEVC/H.265 Main 10 Profile / Level 5.1 Main tier is designed for the compression of 4:2:0 video formats up to 4k at 60 frames per​ second with a bit depth of 10 bits. DICOM provides a mechanism for supporting the use of HEVC/H.265 Image Compression through​ the Encapsulated Format (see PS3.3). Annex A defines a Transfer Syntax that references the HEVC/H.265 Standard.​

The use of the DICOM Encapsulated Format to support HEVC/H.265 compressed pixel data requires that the Data Elements that​ 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 HEVC/H.265 bit​ stream shall be used to decode the compressed data stream.​

Note​

1.​These requirements are specified in terms of consistency with what is encapsulated, rather than in terms of the uncom-​ pressed pixel data from which the compressed data stream may have been derived.​

2.​Whendecompressing,shouldthecharacteristicsexplicitlyspecifiedinthecompresseddatastreambeinconsistentwith​ 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, subject to the general and IOD-specific rules for uncom-​ pressed Photometric Interpretation and Planar Configuration, which may require that decompressed data be converted​ to one of the permitted forms.​

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 16​

•​Bits Stored (0028,0101) shall be 10​

•​High Bit (0028,0102) shall be 9​

•​Pixel Representation (0028,0103) shall be 0​

•​The value of HEVC/H.265 sample aspect_ratio_idc shall be 1 in the encapsulated HEVC/H.265 bit stream if aspect_ra-​ tio_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 values for Rows (0028,0010) , Columns (0028,0011), Cine Rate (0018,0040) , and Frame Time (0018,1063) or Frame Time​ Vector (0018,1065) shall be compliant with the Main 10 Profile / Level 5.1 of the HEVC/H.265 standard [ISO/IEC 23008-2] and re-​ stricted to a square pixel aspect ratio.​

Note​

1.​The value of Planar Configuration (0028,0006) is irrelevant since the manner of encoding components is specified in​ the HEVC/H.265 standard, hence it is set to 0.​

2.​The limitation on rows and columns are to maximize interoperability between software environments and commonly​ available hardware HEVC/H.265 encoder/decoder implementations. Source pictures that have a lower value should be​ re-formatted by scaling and/or pixel padding prior to HEVC/H.265 encoding.​

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.​

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4.​The value of chroma_format_idc for this profile and level is equal to 1, indicating the usage of 4:2:0 content.​

The encapsulated pixel data stream may be segmented into more than one fragment.​

Note​

The recipient is expected to concatenate the fragments while decoding them. This allows for essentially unlimited length​ streams; the only limit imposed is the maximum size of frames (0028,0008) which is 2^31-1.​

ThecontainerformatforthevideobitstreamshallbeMPEG-2TransportStream,a.k.a.MPEG-TS(see[ISO/IEC13818-1])orMPEG-​ 4, a.k.a. MP4 container (see [ISO/IEC 14496-12] and [ISO/IEC 14496-14]). The PTS/DTS of the transport stream shall be used in​ the MPEG coding.​

Any audio components included in the data container shall follow the constraints detailed in Section 8.2.12 Constraints for Audio Data​

Integration in AVC and HEVC Compressed Bit Streams.​

8.2.12 Constraints for Audio Data Integration in AVC and HEVC Compressed Bit Streams​

This section describes the constraints pertaining to the presence of audio data alongside pixel data in DICOM objects. It affects the​ following pixel data encapsulation Transfer Syntaxes:​

•​MPEG-4 AVC/H.264 High Profile / Level 4.1​

•​MPEG-4 AVC/H.264 BD-compatible High Profile / Level 4.1​

•​MPEG-4 AVC/H.264 High Profile / Level 4.2 For 2D Video​

•​MPEG-4 AVC/H.264 High Profile / Level 4.2 For 3D Video​

•​MPEG-4 AVC/H.264 Stereo High Profile / Level 4.2​

•​HEVC/H.265 Main Profile / Level 5.1​

•​HEVC/H.265 Main 10 Profile / Level 5.1​

Any audio components present within a bit stream whose Transfer Syntax is among those listed above shall be interleaved in either​ LPCM, AC-3, AAC, MP3 or MPEG-1 Layer II audio format and shall comply with the following restrictions:​

Table 8.2.12-1. Allowed Audio Formats​

If LPCM is used for Audio components, the container format shall be MPEG-2 TS.​

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•​AC-3​

•​Maximum bit rate: 640kbps​ •​Sampling frequency: 48kHz​ •​Bits per sample: 16 bits​

•​Number of channels: 2 or 5.1 channels​ Note​

1.​AC-3 is standardized in [ETSI TS 102 366]​

2.​If AC-3 is used for Audio components, the container format shall be MPEG-2 TS.​ •​AAC​

•​Maximum bit rate: 640kbps​ •​Sampling frequency: 48kHz​ •​Bits per sample: 16, 20 or 24 bits​

•​Number of channels: 2 or 5.1 channels​ Note​

AAC is standardized in Part 7 of the MPEG-2 standard (see [ISO/IEC 13818-7], and Subpart 4 in Part 3 of the MPEG-4​ standard (see [ISO/IEC 14496-3]).​

•​CBR MPEG-1 LAYER III (MP3) Audio Standard​ •​Maximum bit rate: 320kbps​

•​Sampling frequency: 32 kHz, 44.1 kHz or 48 kHz for the main channel (the complementary channels can be sampled at the half​ rate, as defined in the Standard)​

•​Bits per sample: up to 24 bits​

•​Number of channels: one main mono or stereo channel, and optionally one or more complementary channel(s)​ Note​

1.​MPEG-1 Layer III is standardized in Part 3 of the MPEG-1 standard (see [ISO/IEC 11172-3]).​

2.​Although MPEG describes each channel as including up to 5 signals (e.g., for surround effects), it is recommended​ to limit each of the two channels to 2 signals each one (stereo).​

•​MPEG-1 LAYER II (MP2)​ •​Maximum bit rate: 384kbps​

•​Sampling frequency: 32 kHz, 44.1 kHz or 48 kHz​ •​Bits per sample: up to 24 bits​

•​Number of channels: 2​ Note​

MPEG-1 Layer II is standardized in Part 3 of the MPEG-1 standard (see [ISO/IEC 11172-3]).​

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