Miscellaneous constraints and inferences for the packed regions information SEI message

Abstract

A mechanism for processing video data is disclosed. The mechanism includes determining to specify a horizontal position and a vertical position of a top left sample of an i-th region in a packed regions information (PRI) supplemental enhancement information (SEI) message. A conversion is performed between a visual media data and a bitstream based on the horizontal position and the vertical position of the top left sample of the i-th region in the PRI SEI message. The PRI SEI message can further include constraints to align top-left sample with chroma samples, guarantee a resampling area is within a target picture boundary and to configure a third PRI SEI message between a first and a second PRI SEI messages based on a PRI persistence flag and a PRI cancel flag.

Description

MISCELLANEOUS CONSTRAINTS AND INFERENCES FOR THE PACKED REGIONS INFORMATION SEI MESSAGECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims the benefit of U. S. Pat. Application No.63 / 896,059 filed on October 9, 2025, U. S. Pat. Application No. 63 / 826,203 filed on June 18, 2025, and U. S. Pat. Application No. 63 / 773,156 filed on March 17, 2025, which are hereby incorporated by reference.TECHNICAL FIELD

[0002] The present disclosure relates to generation, storage, and consumption of digital audio video media information in a file format.BACKGROUND

[0003] Digital video accounts for the largest bandwidth used on the Internet and other digital communication networks. As the number of connected user devices capable of receiving and displaying video increases, the bandwidth demand for digital video usage is likely to continue to grow.SUMMARY

[0004] A first aspect relates to a method for processing media data, comprising: determining to specify a horizontal position and a vertical position of a top left sample of an i-th region in a packed regions information (PRI) supplemental enhancement information (SEI) message; and performing a conversion between a visual media data and a bitstream based on the horizontal position and the vertical position of the top left sample of the i-th region in the PRI SEI message.

[0005] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the horizontal position and the vertical position are each coded using an unsigned integer using a variable number of bits (u(v)).

[0006] Optionally, in any of the preceding aspects, another implementation of the aspect provides that a number of bits used to code the horizontal position and the vertical position is specified by pri region size len minus 1 plus 1.

[0007] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the horizontal position and the vertical position of the top left sample of the i th region in a reconstructed target picture are included in the PRI SEI message.

[0008] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the horizontal position and the vertical position are each coded using an unsigned integer using N bits (u(N)), where N is a positive integer.

[0009] Optionally, in any of the preceding aspects, another implementation of the aspect provides that N is equal to 16.

[0010] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the bitstream includes constraints to ensure that the horizontal position and the vertical position of the top left sample of the i-th region are aligned to chroma samples.

[0011] Optionally, in any of the preceding aspects, another implementation of the aspect provides that, when pri_target_pic_params_present_flag is equal to 1, a value of ( pri_target_region_top_left_in_units_x[ i ] * priUnitSize % SubWidthC ) and a value of ( pri_target_region_top_left_in_units_y[ i ] * priUnitSize % SubHeightC ) shall be equal to 0.

[0012] Optionally, in any of the preceding aspects, another implementation of the aspect provides that pri_target_region_top_left_in_units_x[ i ] and pri_target_region_top_left_in_units_y[ i ] indicate horizontal and vertical positions, respectively, of a top left sample position, in units of priUnitSize luma samples, of an i-th region in a reconstructed target picture, wherein priUnitSize represents a PRT unit size, wherein SubWidthC represents a chroma scaling factor in a horizontal direction, and wherein SubHeightC represents a chroma scaling factor in a vertical direction.

[0013] Optionally, in any of the preceding aspects, another implementation of the aspect provides that, when pri_target_pic_params_present_flag is equal to 1, that both ( pri_target_region_top_left_x[ i ] % SubWidthC ) and ( pri_target_region_top_left_y[ i ] % SubHeightC ) shall be equal to 0.

[0014] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the pri_target_region_top_left_x[ i ] and the pri_target_region_top_left_y[ i ] indicate horizontal and vertical positions, respectively, of a top left sample position, in units of priUnitSize luma samples, of an i-th region in a reconstructed target picture, wherein SubWidthC represents a chroma scaling factor in a horizontal direction, and wherein SubHeightC represents a chroma scaling factor in a vertical direction.

[0015] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the bitstream includes constraints to ensure that a resampling area in a reconstructed target picture of a region is within a target picture boundary.

[0016] Optionally, in any of the preceding aspects, another implementation of the aspect provides that, when pri target pic params present flag is equal to 1, a sum of ( pri_target_region_top_left_x[ i ] * priUnitSize ) and priTargetRegionWidth[ i ] shall be less than or equal to ( pri_target_pic_width_minus1 + 1 ), and a sum of ( pri_target_region_top_left_y[ i ] * priUnitSize ) and priTargetRegionHeight[ i ] shall be less than or equal to ( pri target pic height minus 1 + 1 ).

[0017] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the pri_target_region_top_left_x[ i ] and the pri_target_region_top_left_y[ i ] indicate horizontal and vertical positions, respectively, of a top left sample position, in units of priUnitSize luma samples, of an i-th region in a reconstructed target picture, wherein the priTargetRegionWidth and the priTargetRegionHeight represent a width and a height, respectively, in luma samples of a resampled region in the reconstructed target picture, and wherein the pri_target_pic_width_minus1 plus 1 and the pri_target_pic_height_minus1 plus 1 indicate a width and aheight, respectively, in luma samples, of a target picture that may be reconstructed from samples of a cropped decoded picture corresponding to regions described in the PRI SEI message.

[0018] Optionally, in any of the preceding aspects, another implementation of the aspect provides that, when pri_target_pic_params_present_flag is equal to 1, a sum of pri_target_region_top_left_x[ i ] and priTargetRegionWidth[ i ] shall be less than or equal to ( pri target pic width minusl + 1 ) and the sum of pri_target_region_top_left_y[ i ] and priTargetRegionHeight[ i ] shall be less than or equal to ( pri_target_pic_height_minus1 + 1 ).

[0019] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the pri_target_region_top_left_x[ i ] and the pri_target_region_top_left_y[ i ] indicate horizontal and vertical positions, respectively, of a top left sample position, in units of priUnitSize luma samples, of an i-th region in a reconstructed target picture, wherein the priTargetRegionWidth and the priTargetRegionHeight represent a width and a height, respectively, in luma samples of a resampled region in the reconstructed target picture, and wherein priUnitSize represents a PRI unit size.

[0020] Optionally, in any of the preceding aspects, another implementation of the aspect provides that one or more constraints are not included in the PRI SEI message when no target picture is specified.

[0021] Optionally, in any of the preceding aspects, another implementation of the aspect provides that when pri target pic params present flag is equal to 0, pri_num_resampling_ratios_minusl is not included in the bitstream.

[0022] Optionally, in any of the preceding aspects, another implementation of the aspect provides that when pri_target_pic_params_present_flag is equal to 0, pri_resampling_width_num_minusl is not included in the bitstream.

[0023] Optionally, in any of the preceding aspects, another implementation of the aspect provides that when pri_target_pic_params_present_flag is equal to 0, pri_resampling_width_denom_minus1 is not included in the bitstream.

[0024] Optionally, in any of the preceding aspects, another implementation of the aspect provides that when pri target pic params present flag is equal to 0, pri fixed aspect ratio flag is not included in the bitstream.

[0025] Optionally, in any of the preceding aspects, another implementation of the aspect provides that when pri target pic params present flag is equal to 0, pri resampling height num minus 1 is not included in the bitstream.

[0026] Optionally, in any of the preceding aspects, another implementation of the aspect provides that when pri_target_pic_params_present_flag is equal to 0, pri_resampling_height_denom_minus1 is not included in the bitstream.

[0027] Optionally, in any of the preceding aspects, another implementation of the aspect provides that when pri_target_pic_params_present_flag is equal to 0, pri_resampling_ratio_idx is not included in the bitstream.

[0028] Optionally, in any of the preceding aspects, another implementation of the aspect provides that when a first PRI SEI message (priSeiA) and a second PRI SEI message (priSeiB) are present in different access units (AUs) in a coded video sequence (CVS), the priSeiA precedes the priSeiB in output order, and a pri persistence flag of priSeiA is equal to 0, there is no third PRI SEI message (priSeiC) with pri_cancel_flag equal to 1 between the priSeiA and the priSeiB in output order.

[0029] Optionally, in any of the preceding aspects, another implementation of the aspect provides that when a first PRI SEI message (priSeiA) and a second PRI SEI message (priSeiB) are present in different access units (AUs) in a coded video sequence (CVS), the priSeiA precedes the priSeiB in output order, and a pri_persistence_flag of priSeiA is equal to 1, there is no third PRI SEI message (priSeiC) with pri_cancel_flag equal to 1 between the priSeiA and the priSeiB in output order.

[0030] Optionally, in any of the preceding aspects, another implementation of the aspect provides that when a first PRI SEI message (priSeiA) and a second PRI SEI message (priSeiB) are present in different access units (AUs) in a coded video sequence (CVS), the priSeiB follows the priSeiA in output order, a pri_persistence_flag of priSeiA is equal to 1, and a ListOfAssociatedLayers of the priSeiA and a ListOfAssociatedLayers of the priSeiB are not identical but there is m and n such that a value of the ListOfAssociatedLayers [m] of the priSeiA is equal to a value of the ListOfAssociatedLayers [n] of the priSeiB, there shall be a third PRI SEI message (priSeiC) that satisfies the following conditions:a value of a pri cancel flag of priSeiC is equal to 1;the priSeiC is present in a prediction unit (PU) in a same layer as the PU that contains the seiPriA; the priSeiC follows the priSeiA in output order; andthe priSeiC precedes the priSeiB in output order.

[0031] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the conversion includes encoding the visual media data into the bitstream.

[0032] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the conversion includes decoding the visual media data from the bitstream.

[0033] A second aspect relates to an apparatus for processing video data comprising: a processor: and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to perform the method of any of the disclosed aspects.

[0034] A third aspect relates to a non-transitory computer readable medium comprising a computer program product for use by a video coding device, the computer program product comprising computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the video coding device to perform the method of any of the disclosed aspects.

[0035] A fourth aspect relates to a non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises: determining to specify a horizontal position and a vertical position of a top left sample of an i-th regionin a packed regions information (PRI) supplemental enhancement information (SEI) message; and performing a conversion between a visual media data and a bitstream based on the horizontal position and the vertical position of the top left sample of the i-th region in the PRI SEI message.

[0036] A fifth aspect relates to a method for storing a bitstream of a video, comprising: determining to specify a horizontal position and a vertical position of a top left sample of an i-th region in a packed regions information (PRI) supplemental enhancement information (SEI) message; generating the bitstream based on the horizontal position and the vertical position of the top left sample of the i-th region in the PRI SEI message; and storing the bitstream in a non-transitory computer-readable recording medium.

[0037] A sixth aspect relates to a method, apparatus, or system described in the present disclosure.

[0038] For the purpose of clarity, any one of the foregoing embodiments may be combined with any one or more of the other foregoing embodiments to create a new embodiment within the scope of the present disclosure.

[0039] These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0040] For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

[0041] FIG. 1 is a block diagram showing an example video processing system.

[0042] FIG. 2 is a block diagram of an example video processing apparatus.

[0043] FIG. 3 is a flowchart for an example method of video processing.

[0044] FIG. 4 is a block diagram that illustrates an example video coding system.

[0045] FIG. 5 is a block diagram that illustrates an example encoder.

[0046] FIG. 6 is a block diagram that illustrates an example decoder.

[0047] FIG. 7 is a schematic diagram of an example encoder.DETAILED DESCRIPTION

[0048] It should be understood at the outset that although an illustrative implementation of one or more embodiments are provided below, the disclosed systems and / or methods may be implemented using any number of techniques, whether currently known or yet to be developed. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary' designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents.

[0049] Section headings are used in the present disclosure for ease of understanding and do not limit the applicability of techniques and embodiments disclosed in each section only to that section. Furthermore, H.266 terminology is used in some description only for ease of understanding and not for limiting scope of the disclosedtechniques. As such, the techniques described herein are applicable to other video codec protocols and designs also. In the present disclosure, editing changes are shown with respect to the Versatile Video Coding (VVC) specification.1. Initial discussion

[0050] This disclosure is related to image / video coding technologies. Specifically, this disclosure is related to miscellaneous constraints and inferences for the packed regions information supplemental enhancement information (SEI) message. The ideas may be applied individually or in various combinations, for video bitstreams coded by any codec, e.g., the versatile video coding (VVC) standard and / or the versatile supplemental enhancement information (VSEI) messages for coded video bitstreams standard.2. Abbreviations

[0051] Adaptation parameter set (APS), access unit (AU), coded layer video sequence (CLVS), coded layer video sequence start (CLVSS), cyclic redundancy check (CRC), coded video sequence (CVS), finite impulse response (FIR), intra random access point (IRAP), network abstraction layer (NAL), neural-network post¬ processing filter (NNPF), neural-network post-filter activation (NNPFA), neural-network post-filter characteristics (NNPFC), picture parameter set (PPS), picture unit (PU), random access skipped leading (RASL) picture, supplemental enhancement information (SEI), step-wise temporal sublayer access (STSA), uniform resource identifier (URI), video coding layer (VCL), versatile supplemental enhancement information as described in Rec. ITU-T H.274 | ISO / IEC 23002-7 (VSEI), video usability information (VUI), versatile video coding as described in Rec. ITU-T H.266 | ISO / IEC 23090-3 (VVC)3. Further discussion3.1 Video coding standards

[0052] Video coding standards have evolved primarily through the development of International Telecommunication Union (ITU) telecommunication standardization sector (ITU-T) and International Organization for Standardization (ISO) / International Electrotechnical Commission (IEC) standards. The ITU-T produced H.261 and H.263, ISO / IEC produced motion picture experts group (MPEG)-l and MPEG-4 Visual, and the two organizations jointly produced the H.262 / MPEG-2 Video and H.264 / MPEG-4 Advanced Video Coding (AVC) and H.265 / high efficiency video coding (HEVC) [1] standards. Since H.262, the video coding standards are based on the hybrid video coding structure wherein temporal prediction plus transform coding are utilized. To explore video coding technologies beyond high efficiency video coding (HEVC), the Joint Video Exploration Team (JVET) was founded by video coding experts group (VCEG) and motion picture experts group (MPEG). Further, methods have been adopted by JVET and put into the reference software named Joint Exploration Model (JEM) [2], The JVET was later renamed to be the Joint Video Experts Team (JVET) when the Versatile Video Coding (VVC) project officially started. VVC [3] is a coding standard targeting at 50% bitrate reduction as compared to HEVC.

[0053] The Versatile Video Coding (VVC) standard (ITU-T H.266 | ISO / IEC 23090-3) [3] and the associated Versatile Supplemental Enhancement Information for coded video bitstreams (VSEI) standard (ITU-T H.274 | ISO / IEC 23002-7) [4] are designed for use in a maximally broad range of applications, including both the simple uses such as television broadcast, video conferencing, or playback from storage media, and also more advanced use cases such as adaptive bit rate streaming, video region extraction, composition and merging of content from multiple coded video bitstreams, multi-view video, scalable layered coding, and viewport- adaptive 360° immersive media.

[0054] The Essential Video Coding (EVC) standard (ISO / IEC 23094-1) is another video coding standard under development by MPEG.3.2 SEI messages in general and in VVC and VSEI

[0055] SEI messages assist in processes related to decoding, display or other purposes. However, SEI messages are not required for constructing the luma or chroma samples by the decoding process. Conforming decoders are not required to process this information for output order conformance. Some SEI messages are required for checking bitstream conformance and for output timing decoder conformance. Other SEI messages are not required for check bitstream conformance.

[0056] Annex D of VVC specifies syntax and semantics for SEI message payloads for some SEI messages, and specifies the use of the SEI messages and VUI parameters for which the syntax and semantics are specified in ITU-T H.274 | ISO / IEC 23002-7.3.3 Packed regions information (PRI) SEI message

[0057] JVET-AK2006-v3 [4] includes the specification of the packed regions information (PRI) SEI message, as follows.8.42 Packed regions information SEI message8.42.1 Packed regions information SEI message syntaxpacked_regions_info( payloadSize) Descriptor pri_cancel_flag u(1) if (!pri_cancel_flag ) {pri_persistence_flag u(1) pri_num_regions_minus1 ue(v) pri_multilayer_flag u(1) pri_use_max_dimensions_flag u(l) pri_log2_unit_size u(4) pri_region_size_len_minus1 u(4) pri_region_id_present_flag u(l) pri_target_pic_params_present_flag u(1){ [ (A)n [ I J. A~Jja[~dOJ~UO[Haj~jaHjBJ~ljd (A)n [ i ]x~jja[~doj~uoi§aj~ja§jBj~ud ( SBU~juasaid~sujB.red~Aid~jaS.rej~Lid )JI (A)n [ T Jxpi~oijB.t~Hui|duiBsa.i~ijd ( 0 < Isnuiuj~soijBj~§ut[diuBsaj~uinu~pd )JI { (A)n [ i ] xsnuiui~sjiun~ui~jqSiaq~uoi8a.i~ijd (A)n [ i ] [siiuiui~sjiun~ui~qjptAA~uoiHa.t~i.id (A)n [ i | A Sjnrn ui j|.j| doj uoiH,jj ijd (A)n [ i Jx~sjiun~ui~j[a[~doj~uoiHa.t~i.id } ( [ i |HB|] _IAA'B| B si itoiHa.i Lid; )JI { (T)n [ J ]3i:[j~J3Ai:[~i:~si~uoiHAj~ijd (A)SH [ i Jpt~jaAB[~uoiHaj~ud } ( 31? | j.ia <iqii|ntn Lid )JI (,\)an [ i ] pi~uoi§aj~ud ( o(:|[~|irasaid~pi~i« >t8aj~ud )JT } ( ++t: j snurai~suoi§M~mnu~ud => i:<) = i )JOJ { { (A)an [ i ] [snuiiu~tuouap~jqHiaq~Hui|diuBsa.i~i.id (A)SH [ i | [snunu tunu jqniaq <iuqdtuBsaj ijd } ( [ i ]3BU~oijBj~joadsB~paxy~udj )JI (I)n [ i |HB|j orjBj jaadsB paxij ijd (A)SH [ t J[snuitu~iuouap~qjpiAA~HuqdiuBsaj~ijd (A)an [ t Jisnuiui tunu qjpiu^iuqduiBsaj ijd } ( ++i: jsnuraj~soijBj~SuqdniBsaj~uinu~ud => i ‘ j = i )JOJ (Apii |snuiui~soijB.i~3uqduiBsa.i~uinu~i.id { (9l)n|snuiui~jq3iat|~.jid~ja3.iBj~i.id u(16) [snunu~qjpiAA~Aid~ja8.tBj~i.id} ( §B|j~juasa.id~suiB. TBd~Aid~ja8. TBj~ud )jt8.42.2 Packed regions information SEI message semantics

[0058] The packed regions information SEI message provides information regarding rectangular regions packed with the coded picture. This information may optionally be used to reconstruct a target picture from the samples of the cropped decoded picture corresponding to the regions described in this SET message.

[0059] Use of this SEI message requires the definition of the following variables:- A picture width and picture height in units of luma samples, denoted herein by PicWidthlnLumaSamples and PicHeightlnLumaSamples, respectively.- A maximum picture width and maximum picture height in units of luma samples, denoted herein by MaxPicWidth and MaxPicHeight, respectively.- A chroma format indicator, denoted herein by ChromaFormatIdc, as described in clause 7.3 of the VSEI spec.- A bit depth for the samples of the luma component, denoted herein by BitDepthY, and when ChromaFormatldc is not equal to 0, a bit depth for the samples of the two associated chroma components, denoted herein by BitDepthC.

[0060] pri cancel flag equal to 1 indicates that the SEI message cancels the persistence of any previous packed regions information SEI message in output order that applies to the current layer. pri_cancel_flag equal to 0 indicates that packed regions information follows.

[0061] pri_persistence_flag specifies the persistence of the packed regions information SEI message for the current layer. pri_

[0062] persistence_flag equal to 0 specifies that the packed regions information applies to the current decoded picture only.

[0063] pri_persistence_flag equal to 1 specifies that the packed regions information SEI message applies to the current decoded picture and persists for all subsequent pictures of the current layer in output order until one or more of the following conditions are true:- A new CL VS of the current layer begins.- The bitstream ends.- A picture in the current layer in an AU associated with a packed regions information SEI message is output that follows the current picture in output order.

[0064] pri_num_regions_minusl plus 1 specifies the number of regions for which information is signalled.

[0065] pri_multilayer_flag equal to 1 specifies that the pri_region_layer_id[ i ] syntax element is present, pri multilayer flag equal to 0 specifies that the pri region layer id [ i ] syntax element is not present.T0066] pri_use_max_dimensions_flag equal to 1 specifies that MaxPicWidth, MaxPicHeight, PicWidthlnLumaSamples and PicHeightlnLumaSamples will be used in variable calculations. pri_use_max_dimensions_flag equal to 0 specifies that MaxPicWidth, MaxPicHeight, PicWidthlnLumaSamples and PicHeightlnLumaSamples will not be used in variable calculations for the region parameters.

[0067] pri_log2_unit_size specifies a unit size used in variable calculations for the region parameters.

[0068] The variable priUnitSize is set equal to 1 << pri_log2_unit_size.

[0069] pri region size len minus1 plus 1 specifies the number of bits used to signal pri_region_top_left_in_units_x[ i ], pri_region_top_left_in_units_y[ i ], pri_region_width_in_units_minusl[ i ], pri_region_height_in_units_minusl[ i ], pri_target_region_top_left_x[ i ], and pri_target_region_top_left_y[ i ].

[0070] pri_region_id_present_flag equal to 1 indicates the pri_region_id[ i ] syntax element is present. pri_region_id_present_flag equal to 0 indicates the pri_region_id[ i ] syntax element is not present.

[0071] pri_target_pic_params_present_flag equal to 1 indicates that the pri_target_region_top_left_x[ i ], pri_target_region_top_left_y[ i ], pri target pic width minusl, and pri_target_pic_height_minus1 syntax elements are present. pri target pic params present flag equal to 0 indicates that the pri_target_region_top_left_x[ i ], pri_target_region_top_left_y[ i ], pri_target_pic_width_minus1, and pri_target_pic_height_minus1 syntax elements are not present.

[0072] pri_target_pic_width_minus1 plus 1 and pri_target_pic_height_minus1 plus 1, when present, indicate the width and height, respectively, in luma samples of the target picture that may be reconstructed from the samples of the cropped decoded picture corresponding to the regions described in this SEI message.

[0073] pri_num_resampling_ratios_minus1 plus 1 specifies the number of resampling ratios that are signalled.

[0074] pri_resampling_width_num_minus1[ i ] plus 1 and pri_resampling_width_denom_minus1[ i ] plus 1 specify the numerator and denominator, respectively, for the width resampling of the i-th resampling ratio. Both pri_resampling_width_num_minus1[ i ] and pri_resampling_width_denom_minus1[ i ] shall be in the range of 0 to 65535, inclusive.

[0075] When not present, the values of pri_resampling_ratio_width_num_minus1

[0000] and pri_resampling_ratio_width_denom_minus1

[0000] are inferred to be equal to 0.

[0076] pri_fixed_aspect_ratio_flag[ i ] equal to 1 specifies that the pri_resampling_height_num_minus1 [ i ] and pri_resampling_height_denom_minus1[ i ] syntax elements are not present. pri_fixed_aspect_ratio_flag[ i ] equal to 0 specifies that the pri_resampling_height_num_minus1 [ i ] and pri_resampling_height_denom_minus1[ i ] syntax elements are present.

[0077] pri_resampling_height_num_minusl[ i ] plus 1 and pri_resampling_height_denom_minus1[ i ] plus 1 specify the numerator and denominator, respectively, for the height resampling of the i-th resampling ratio. Both pri_resampling_height_num_minus1 [ i ] and pri_resampling_height_denom_minusl [ i ] shall be in the range of 0 to 65535, inclusive. When not present, the values of pri_resampling_height_num_minus1[ i ] andpri_resampling_height_denom_minus 1 [ i ] are inferred to be equal to the pri_resampling_width_num_minus 1 [ i ] and pri_resampling_width_denom_minusl [ i ], respectively.

[0078] pri_region_id[ i ] indicates the ID of the i-th region. When not present, the value of pri_region_id[ i ] is inferred to be equal to i.

[0079] pri_region_layer_id[ i ] specifies the layer identifier of the picture that the region information pri region top left in units x[ i ], pri region top left in units y[ i ], pri region width in units minusl[ i ], pri region height in units minusl[ i ] relate to. When not present, the value of pri region layer id[ i ] is inferred to be equal to 0.

[0080] pri_region_is_a_layer_flag[ i ] equal to 1 specifies that the picture width and height in the layer of layer identifier equal to pri_region_layer_id[ i ] are the same as the width and height of region of index i, and pri_region_top_left_in_units_x[ i ], pri_region_top_left_in_units_y[ i ], pri_region_width_in_units_minus1 [ i ], pri_region_height_in_units_minus1[ i ] are not signalled. When not present, the value of pri_region_is_a_layer_flag[ i ] is inferred to be equal to 0.

[0081] pri_region_top_left_in_units_x[ i ] and pri_region_top_left_in_units_y[ i ] specify the horizontal and vertical positions, respectively, of the top left sample of the i-th region in units. The length of the syntax elements are pri region size len minusl + 1.

[0082] The variables priRegionTopLeftX[ i ] and priRegionTopLeftY[ i ], representing the horizontal and vertical positions, respectively, in luma samples of the i-th region in the cropped decoded picture with layer identifier equal to pri region layer id[ i ], are derived as follows:if(!pri_use_max_dimensions_flag ) {priRegionTopLeftX[ i ] = pri_region_top_left_in_units_x[ i ] * priUnitSize priRegionTopLeftY[ i ] = pri_region_top_left_in_units_y[ i ] * priUnitSize} else {priRegionTopLeftX[ i ] = ( pri_region_top_left_in_units_x[ i ] * priUnitSize * PicWidthInLumaSamples + MaxPicWidth / 2 ) / MaxWidthpriRegionTopLeftY[ i ] = ( pri_region_top_left_in_units_y[ i ] * priUnitSize* PicHeightInLumaSamples + MaxPicHeight / 2 ) / MaxHeight}

[0083] pri_region_width_in_units_minusl [ i ] plus 1 and pri_region_height_in_units_minus1[ i ] plus 1 specify the horizontal and vertical positions, respectively, of the width and height of the i-th region in units. The length of the syntax elements are pri region size len minusl + 1.

[0084] The variables priRegionWidthf i ] and priRegionHeightf i ], representing the width and height, respectively, in luma samples of the i-th region in the cropped decoded picture are derived as follows:if(!pri_use_max_dimensions_flag ) {priRegion Width [ i ] = ( pri_region_width_in_units_minusl [ i ] + 1) * priUnitSizepriRegionHeight[ i ] = ( pri_region_height_in_units_minusl [ i ] + 1) * priUnitSize} else {priRegionWidth[ i ] = ( ( pri_region_width_in_units_minus1[ i ] + 1) * priUnitSize * PicWidthInLumaSamples + MaxPicWidth / 2 ) / MaxWidthpriRegionHeight[ i ] = ( ( pri_region_height_in_units_minus1 [ i ] + 1) * priUnitSize * PicHeightInLumaSamples + MaxPicHeight / 2 ) / MaxHeight}

[0085] The variables SubWidthC and SubHeightC are derived from ChromaFormatldc as specified by Table 2 of the VSEI spec.

[0086] It is a requirement of bitstream conformance that priRegionWidth[ i ] % SubWidthC shall be equal to 0 and priRegionHeight[ i ] % SubHeightC shall be equal to 0.

[0087] pri resampling ratio idx[ i ] specifies the index of the resampling ratio used for the i-th region. The value of pri_resampling_ratio_idx[ i ] shall be in the range of 0 to pri_num_resampling_ratios_minusl, inclusive. Tile length of the syntax element is Ceil( Log2( pri_num_resampling_ratios_minusl + 1 ) ) bits.

[0088] The variables priResampleWidthNum[ i ], priResampleWidthDenom[ i ], priResampleHeightNum[ i ], and priResampleHeightDenom[ i ] are derived as follows:priResampleWidthNum[ i ] = pri_resampling_width_num_minus1[ pri_resampling_ratio_idx[ i ] ] + 1 priResampleWidthDenom[ i ] = pri_resampling_width_denom_minus1[ pri_resampling_ratio_idx[ i ] ] + 1 priResampleHeightNum[ i ] = pri_resampling_height_num_minus1[ pri_resampling_ratio_idx[ i ] ] + 1 ) priResampleHeightDenom[ i ] = pri_resampling_height_denom_minus1[ pri_resampling_ratio_idx[ i ] ] + 1

[0089] pri_target_region_top_left_x[ i ] and pri_target_region_top_left_y[ i ], when present, indicate the horizontal and vertical positions, respectively, of the top left sample position in luma samples of the i-th region in the reconstructed target picture.

[0090] The variables priTargetRegionWidth and priTargetRegionHeight, representing the width and height, respectively, in luma samples of the resampled region in the reconstructed target picture, are derived as follows:priTargetRegionWidth = Round( ( priRegionWidth[ i ] * priResampleWidthNum[ i ] ) ÷ ( priResampleWidthDenom[ i ] * SubWidthC ) ) * SubWidthCpriTargetRegionHeight = Round( ( priRegionHeight[ i ] * priResampleHeightNum[ i ] ) ÷ ( priResampleHeightDenom[ i ] * SubHeightC ) ) * SubHeightC

[0091] When reconstructing a target picture with luma sample array of size ( pri_target_pic_width_minus1 4- 1 ) x ( pri_target_pic_height_minus1 + 1 ), all luma sample values are initialized to value 1 « ( BitDepthY -f ) and chroma samples, if present, to f << ( BitDepthC — 1 ).

[0092] When all of the following conditions are true for any sample position (x,y) and regions j and k, the reconstructed target picture sample at position (x, y) should be determined by the parameters signalled for the j-th region:- pri_region_id[ j ] is greater than pri_region_id[ k ] - x is in the range of priRegionTopLeftX[ j ].. priRegionTopLeftX[ j ] + priRegion Width [ j ] - y is in the range of priRegionTopLeftY[ j ].. priRegionTopLeftY[ j ] + priRegionHeight[ j ] - x is in the range of priRegionTopLeftX[ k ].. priRegionTopLeftX[ k ] + priRegionWidth[ k] - y is in the range of priRegionTopLeftY[ k ].. priRegionTopLeftY[ k ] + priRegionHeight[ k ] 3.4 Use of PRI SEI messages in VVC bitstreams

[0093] JVET-AK2005-v2 [5] includes the specification of use of PRI SEI messages in VVC bitstreams, also referred to as the interface text for the PRI SEI message, as follows.D.12.20 Use of the packed regions information SEI message

[0094] For purposes of interpretation of the packed regions information SEI message, the following variables are specified:- PicWidthlnLumaSamples is set equal to the value of pps_pic_width_in_luma_samples - SubWidthC * ( pps_conf_win_left_offset + pps_conf_win_right_offset ).- PicHeightInLumaSamples is set equal to the value of pps_pic_height_in_luma_samples - SubHeightC * ( pps_conf_win_top_offset + pps_conf_win_bottom_offset ).- MaxPicWidth is set equal to the value of sps_pic_width_in_luma_samples - SubWidthC * ( sps_conf_win_left_offset + sps_conf_win_right_offset ).- MaxPicHeight is set equal to the value of sps_pic_height_in_luma_samples - SubHeightC * ( sps_conf_win_top_offset + sps_conf_win_bottom_offset ).- ChromaFormatldc is set equal to sps_chroma_format_idc.- BitDepthY and BitDepthC are both set equal to BitDepth.3.5 Packed regions information (PRI) SEI message design in JVET-AN0367-v1

[0095] In JVET-AN0367, various constraints are added to the PRI SEI message text based on JVET-AM2006, shown as follows:8.39 Packed regions information SEI message8.39.1 Packed regions information SEI message syntaxpacked_regions_info( payloadSize) Descriptor pri_cancel_flag u(1) if( Ipri cancel flag ) {pri_persistence_flag u(1) pri_num_regions_minus1 ue(v) pri_multilayer_flag u(1) pri_use_max_dimensions_flag u(l)pri_log2_u nit_size u(4) pri_region_size_len_minus1 u(4) pri_region_id_present_flag u(l) pri_target_pic_params_present_flag u(1) if( pri_target_pic_params_present_flag ) {pri_target_pic_width_minus1 u(16) pri_target_pic_height_minus1 LI(16) }pri_num_resampling_ratios_minusl ue(v) for( i = 1; i <= pri_num_resampling_ratios_minusl; i++ ) { pri_resampling_width_num_minus1[ i ] ue(v) pri_resampling_width_denom_minus1[ i ] ue(v) pri_fixed_aspect_ratio_flag[ i ] u(l) if(!pri_fixed_aspect_ratio_flag[ i ] ) {pri_resampling_height_num_minusl[ i ] ue(v) pri_resampling_height_denom_minus1[ i ] ue(v) }}for( i = 0; i <= pri_num_regions_minusl; i++ ) {if( pri region id present flag )pri_region_id[ i ] ue(v) if( pri_multilayer_flag ) {pri_region_layer_id[ i ] ue(v) pri_region_is_a_layer_flag[ i ] u(1) )if(!pri_region_is_a_layer_flag[ i ] ) {pri_region_top_left_in_units_x[ i ] u(v) pri_region_top_left_in_units_y[ i ] u(v) pri_region_width_in_units_minusl[ i ] u(v) pri_region_height_in_units_minusl[ i ] u(v) }if( pri_num_resampling_ratios_minusl > 0 )pri_resampling_ratio_idx[ i ] u(v) if( pri_target_pic_params_present_flag )pri_target_region_top_left_in_units_x[ i ] u(v) pri_target_region_top_left_in_units_y[ i ] u(v)]}}}8.39.2 Packed regions information SEI message semantics

[0096] The packed regions information (PRI) SEI message provides information regarding rectangular regions packed with the coded pictures of one or more layers. This information may optionally be used to reconstruct a target picture from the samples of the cropped decoded picture(s) corresponding to the regions described in this SEI message.

[0097] Use of this SET message requires the definition of the following variables:- For each layer with a particular layer identifier value pri_region_layer_id[ i ], a picture width and picture height in units of luma samples, denoted herein by PicWidthInLumaSamples[ pri_region_layer_id[ i ] ] and PicHeightInLumaSamples[ pri_region_layer_id[ i ] ], respectively.- For each layer with a particular layer identifier value pri_region_layer_id[ i ], a maximum picture width and maximum picture height in units of luma samples, denoted herein by MaxPicWidth[ pri_region_layer_id[ i ] ] and MaxPicHeight[ pri_region_layer_id[ i ] ], respectively. - A chroma format indicator, denoted herein by ChromaFormatldc, as described in subclause 7.3.- A bit depth for the samples of the luma component, denoted herein by BitDepthValY, and a bit depth for the samples of the two associated chroma components, denoted herein by BitDepthValC.

[0098] NOTE - When ChromaFormatldc is equal to 0, BitDepthValC is not used.

[0099] The ListOfAssociatedLayers of a PRI SEI message is the list of layer identifiers containing unique values of pri_region_layer_id[ i ], in ascending order, for i in the range from 0 to pri_num_regions_minusl, inclusive, in the PRI SEI message.

[0100] When two or more PRI SEI messages are present in an AU, both of the following apply:- All the PRI SEI messages that are present in the same PU shall have the same content.- When PRI SEI message priSeiA and PRI SEI message priSeiB are present in the same AU but in different PUs, the values in the ListOfAssociatedLayers of seiPriA and seiPriB shall be mutually exclusive.

[0101] When PRI SEI message priSeiA and PRI SEI message priSeiB are present in the different AU in the CVS, priSeiB follows priSeiA in output order, and the ListOfAssociatedLayers of priSeiA and the ListOfAssociatedLayers of priSeiB are not identical but there is m and n such that the value of ListOfAssociatedLayers[m] of priSeiA is equal to the value of ListOfAssociatedLayers[n] of priSeiB, it is constrained that there shall be another PRI SEI message priSeiC that satisfies all of the following:- The value of pri_cancel_flag of priSeiC is equal to 1.- priSeiC is present in a PU in the same layer as the PU that contains seiPri A.- priSeiC follows priSeiA in output order.- priSeiC precedes priSeiB in output order.

[0102] When a PRI SEI message is present in an AU, the PRI SEI message shall be present in the PU which has layer identifier equals to the lowest value of pri_region_layer_id[ i ] for i in the range from 0 to pri_num_regions_minusl, inclusive.

[0103] pri_cancel_flag equal to 1 indicates that the SEI message cancels the persistence of any previous packed regions information SEI message, in output order, in the same CLVS. pri_cancel_flag equal to 0 indicates that packed regions information follows.

[0104] For two SEI messages seiA and seiB in two different AUs, seiB is said to be following seiA in output order when any picture in the AU containing seiB follows any picture in the AU containing seiA in output order.

[0105] pri_persistence_flag specifies the persistence of the packed regions information SEI message.

[0106] pri_persistence_flag equal to 0 specifies that the packed regions information applies to the current AU only.

[0107] pri_persistence_flag equal to 1 specifies that the packed regions information SEI message in the current CLVS applies to pictures in the current AU and persists for pictures in all subsequent AUs in output order in the current CVS until an AU, when present, that follows the current AU in output order and contains a packed regions information SEI message in the same CLVS.

[0108] NOTE - The pictures to which the persistence of PRI SEI message applies to are pictures with layer identifier equal to one of the value of pri_region_layer_id[ j ] and layer identifier of the PU where the SEI message is present

[0109] pri_num_regions_minusl plus 1 specifies the number of regions for which information is signalled. The value of pri num regions minus 1 shall be in the range of 0 to 255, inclusive.

[0110] pri_multilayer_flag equal to 1 specifies that the pri_region_layer_id[ i ] and pri region is a layer _Hag[ i ] syntax elements are present, pri multilayer flag equal to 0 specifies that the pri_region_layer_id[ i ] and pri_region_is_a_layer_flag[ i ] syntax element are not present.

[0111] pri use max dimensions flag equal to 1 specifies that the region parameters are calculated based on the maximum picture size and that MaxPicWidth[ ], MaxPicHeight[ ], PicWidthInLumaSamples[ ] and PicHeightInLumaSamples[ ] are used in variable calculations for the region parameters. pri_use_max_dimensions_flag equal to 0 specifies that the region parameters are calculated based on the current picture size and that MaxPicWidth[ ], MaxPicHeight[ ], PicWidthInLumaSamples[ ] and PicHeightInLumaSamples[ ] are not used in variable calculations for the region parameters.

[0112] pri_log2_unit_size specifies a unit size used in variable calculations for the region parameters.

[0113] The variable priUnitSize is set equal to 1 « pri log2 unit size.

[0114] pri_region_size_len_minus1 plus 1 specifies the number of bits used to signal pri_region_top_left_in_units_x[ i ], pri_region_top_left_in_units_y[ i ], pri_region_width_in_units_minus1[ i ], pri_region_height_in_units_minus1[ i ], pri_target_region_top_left_in_units_x[ i ], and pri_target_region_top_left_in_units_y[ i ].

[0115] pri_region_id_present_flag equal to 1 indicates the pri_region_id[ i ] syntax element is present, pri region id present flag equal to 0 indicates the pri region id [ i ] syntax element is not present.

[0116] pri_target_pic_params_present_flag equal to 1 indicates that the pri_target_region_top_ left_in_units_x[ i ], pri target region top left in units y[ i ], pri target pic width minusl, and pri_target_pic_height_minus1 syntax elements are present. pri_target_pic_params_present_flag equal to 0 indicates that the pri_target_region_top_left_in_units_x[ i ], pri_target_region_top_left_in_units_y[ i ], pri_target_pic_width_minus1, and pri_target_pic_height_minus1 syntax elements are not present.

[0117] pri_target_pic_width_minus1 plus 1 and pri_largel_pic_height_minusl plus 1, when present, indicate the width and height, respectively, in luma samples, of the target picture that may be reconstructed from the samples of the cropped decoded picture corresponding to the regions described in this SEI message.

[0118] The value of ( pri target pic width minusl + 1 ) % SubWidthC shall be equal to 0. The value of ( pri target pic height minusl + 1 ) % SubHeightC shall be equal to 0.

[0119] The variables SubWidthC and SubHeightC are derived from ChromaFormatldc as specified by Table 2.

[0120] pri num resampling ratios minusl plus 1 specifies the number of resampling ratios that are signalled. The value of pri_num_resampling_ratios_minusl shall be in the range of 0 to pri_num_regions_minus 1, inclusive.

[0121] pri_resampling_width_num_minus1[ i ] plus 1 and pri_resampling_width_denom_minus1[ i ] plus 1 specify the numerator and denominator, respectively, for the width resampling of the i-th resampling ratio. Both pri resampling width num minusl [ i ] and pri resampling width denom minus 1[ i ] shall be in the range of 0 to 65535, inclusive.

[0122] The values of pri_resampling_width_num_minus1

[0000] and pri_resampling_width_denom_minus1

[0000] are set to be equal to 0.

[0123] When pri_target_pic_params_present_flag is equal to 1, ( pri_resampling_width_num_minus1[ i ] + 1 ) ÷ ( pri_resampling_width_denom_minus1[ i ] + 1 ) shall be in the range of 1 ÷ 16 to 16, inclusive,

[0124] pri_fixed_aspect_ratio_flag[ i ] equal to 1 specifies that the pri_resampling_height_num_minusl[ i ] and pri_resampling_height_denom_minusl [ i ] syntax elements are not present. pri_fixed_aspect_ratio_flag[ i ] equal to 0 specifies that the pri resampling height num minusl [ i ] and pri resampling height denom_minusl[ i ] syntax elements are present.

[0125] pri_resampling_height_num_minus1[ i ] plus 1 and pri_resampling_height_denom_minus1[ i ] plus 1 specify the numerator and denominator, respectively, for the height resampling of the i-th resampling ratio. Both pri_resampling_height_num_minusl[ i ] and pri_resampling_height_denom_minus1[ i ] shall be in the range of 0 to 65535, inclusive.

[0126] When not present, the values of pri_resampling_height_num_minusl[ i ] and pri resampling height denom minus 1 [ i ] are inferred to be equal to the pri resampling width num minus 1 [ i ] and pri resampling width denom minus 1[ i ], respectively.

[0127] When pri target pic params present flag is equal to 1, ( pri resampling height num_minusl[ i ] + 1 ) -? ( pri_resampling_height_denom_minus1[ i ] + 1 ) shall be in the range of 1 -? 16 to 16, inclusive.

[0128] pri_region_id[ i ] indicates the region ID of the i-th region. When not present, the value of pri_region_id[ i ] is inferred to be equal to i. The value of pri_region_id[ i ] shall be in the range of 0 to 1023, inclusive.

[0129] For any two different values of i and j in the range of 0 to pri_num_regions_minusl, inclusive, pri_region_id[ i ] shall not be equal to pri_region_id[ j ].

[0130] pri_region_layer_id[ i ] specifies the layer identifier of the picture that the region information pri region top left in units x[ i ], pri region top left in units y[ i ], pri region width in units minusl[ i ], pri_region_height_in_units_minusl[ i ] relate to. The value of pri_region_layer_id[ i ] shall be in the range of 0 to 2047, inclusive.

[0131] When not present, the value of pri_region_layer_id[ i ] is inferred to be equal to the layer identifier of the PU containing the PRI SEI message, where the layer identifier of a PU is the layer identifier of the VCL NAL units of the coded picture in the PU.

[0132] pri_region_is_a_layer_flag[ i ] equal to 1 specifies that that the width and height of the i-th region tire the same as the picture width and height, respectively, in the layer with layer identifier equal to pri_region_layer_id[ i ], and pri_region_top_left_in_units_x[ i ], pri_region_top_left_in_units_y[ i ], pri_region_width_in_units_minusl[ i ], pri_region_height_in_units_minusl[ i ] are not present. When not present, the value of pri_region_is_a_layer_flag[ i ] is inferred to be equal to 0.

[0133] When pri_region_is_a_layer_flag[ i ] is equal to 0, pri_region_top_left_in_units_x[ i ] and pri region top left in unitsi ] specify the horizontal and vertical positions, respectively, of the top left sample of the i-th region in units of priUnitSize luma samples. The length, in bits, of the syntax elements are pri_region_size_len_minusl + 1.

[0134] The variables priRegionTopLeftX[ i ] and priRegionTopLeftY[ i ], representing the horizontal and vertical positions, respectively, in luma samples of the i-th region in the cropped decoded picture with layer identifier equal to pri_region_layer_id[ i ], are derived as follows:if( pri_region_is_a_layer_flag[ i ] ) { priRegionTopLeftX[ i ] = 0 priRegionTopLeftY[ i ] = 0} else if(!pri_use_max_dimensions_flag ) { priRegionTopLeftX[ i ] = pri_region_top_left_in_units_x[ i ] * priUnitSizepriRegionTopLeftY[ i ] = pri_region_top_left_in_units_y[ i ] * priUnitSize} else {priRegionTopLeftX[ i ] = ( pri_region_top_left_in_units_x[ i ] * priUnitSize *PicWidthInLumaSamples[ pri_region_layer_id[ i ] ] +MaxPicWidth[ pri_region_layer_id[ i ] ] / 2 ) / MaxPicWidth[ pri_region_layer_id[ i ] ]priRegionTopLeftY[ i ] = ( pri_region_top_left_in_units_y[ i ] * priUnitSize*PicHeightInLumaSamples[ pri_region_layer_id[ i ] ] +MaxPicHeight[ pri_region_layer_id[ i ] ] / 2 ) / MaxPicHeightf pri_region_layer_id[ i ] ])

[0135] The value of priRegionTopLeftX[ i ] % SubWidthC shall be equal to 0. The value of priRegionTopLeftY[ i ] % SubHeightC shall be equal to 0.

[0136] When pri_region_is_a_layer_flag[ i ] is equal to 0, pri_region_width_in_units_minus 1 [ i ] plus 1 and pri region height in units minsul[ i ] plus 1 specify the width and height, respectively, of the i-th region in units of priUnitSize luma samples. The length, in bits, of the syntax elements are pri_region_size_len_minus 1 + 1.

[0137] The variables priRegionWidth[ i ] and priRegionHeightf i ], representing the width and height, respectively, in luma samples of the i-th region in the cropped decoded picture with layer identifier equal to pri region layer id[ i ] are derived as follows:if( pri_region_is_a_layer_flag[ i ] ) {priRegionWidth[ i ] = PicWidthInLumaSamples[ pri_region_layer_id[ i ] ] priRegionHeightf i ] = PicHeightlnLumaSamplesf pri_region_layer_id[ i ] ]} else if(!pri_use_max_dimensions_flag ) {priRegionWidth[ i ] = ( pri_region_width_in_units_minusl[ i ] + 1 ) * priUnitSize priRegionHeight[ i ] = ( pri_region_height_in_units_minusl[ i ] + 1 ) * priUnitSize } else {priRegionWidth[ i ] = ( ( pri_region_width_in_units_minusl[ i ] + 1 ) * priUnitSize *PicWidthInLumaSamples[ pri_region_layer_id[ i ] ] +MaxPicWidthf pri_region_layer_id[ i ] ] / 2 ) / MaxPicWidth[ pri_region_layer_id[ i ] ]priRegionHeight[ i ] = ( ( pri_region_height_in_units_minusl [ i ] + 1 ) * priUnitSize *PicHeightInLumaSamples[ pri_region_layer_id[ i ] ] +MaxPicHeight[ pri_region_layer_id[ i ] ] / 2 ) / MaxPicHeight[ pri_region_layer_id[ i ] ]}

[0138] It is a requirement of bitstream conformance that priRegionWidth[ i ] % SubWidthC shall be equal to 0 and priRegionHeightf i ] % SubHeightC shall be equal to 0.

[0139] The sum of priRegionTopLeftX[ i ] and priRegionWidth[ i ] shall be less than or equal to PicWidthInLumaSamples[ pri_region_layer_id[ i ] ]. The sum of priRegionTopLeftY[ i ] and priRegionHeight[ i ] shall be less than or equal to PicHeightInLumaSamples[ pri_region_layer_id[ i ] ].

[0140] pri resampling ratio idx[ i ] specifies the index of the resampling ratio used for the i-th region. The value of pri_resampling_ratio_idx[ i ] shall be in the range of 0 to pri_num_resampling_ratios_minusl, inclusive. The length of the syntax element is Ceil( Log2( pri_num_resampling_ratios_minus1 + 1 ) ) bits. When not present, the value of pri_resampling_ratio_idx[ i ] is inferred to be equal to 0.

[0141] The variables priResampleWidthNum[ i ], priResampleWidthDenom[ i ], priResampleHeightNum[ i ], and priResampleHeightDenom[ i ] are derived as follows:priResampleWidthNum[ i ] = pri_resampling_width_num_minus1[ pri_resampling_ratio_idx[ i ] ] + 1 priResampleWidthDenom[ i ] = pri_resampling_width_denom_minus1[ pri_resampling_ratio_idx[ i ] ] + 1 priResampleHeightNum[ i ] = pri_resampling_height_num_minus1[ pri_resampling_ratio_idx[ i ] ] + 1 ) priResampleHeightDenom[ i ] =pri_resampling_height_denom_minusl[ pri_resampling_ratio_idx[ i ] ] + 1

[0142] When pri_target_pic_params_present_flag is equal to 0, the resampling ratio values indicate the resampling ratios of the regions from the source picture.

[0143] pri_target_region_top_left_in_units_x[ i ] and pri_target_region_top_left_in_units_y[ i ], when present, indicate the horizontal and vertical positions, respectively, of the top left sample position, in units of priUnitSize luma samples, of the i th region in the reconstructed target picture. The length, in bits, of the syntax elements are pri_region_size_len_minus1 + 1.

[0144] When pri target pic params present flag is equal to 1, the value of ( pri_target_region_top_left_in_units_x[ i ] * priUnitSize % SubWidthC ) shall be equal to 0, and the value of ( pri_target_region_top_left_in_units_y[ i ] * priUnitSize % SubHeightC ) shall be equal to 0.

[0145] When pri_target_pic_params_present_flag is equal to 1, the variables priTargetRegionWidth and priTargetRegionHeight, representing the width and height, respectively, in luma samples of the resampled region in the reconstructed target picture, are derived as follows:if(!pri_use_max_dimensions_flag )priTargetRegionWidth = Round( ( priRegionWidth[ i ] * priResampleWidthNum[ i ] ) ÷ ( priResampleWidthDenom[ i ] * SubWidthC ) ) * SubWidthC priTargetRegionHeight = Round( ( priRegionHeight[ i ] * priResampleHeightNum[ i ] ) ÷ ( priResampleHeightDenom[ i ] * SubHeightC ) ) * SubHeightC} else (priTargetRegionWidth = Round( ( priRegionWidth[ i ] * priResampleWidthNum[ i ] * MaxPicWidth[ pri_region_layer_id[ i ] ] ) ÷ ( priResampleWidthDenom[ i ] * PicWidthInLumaSamples[ pri_region_layer_id[ i ] ] * SubWidthC ) ) * SubWidthC priTargetRegionHeight = Round( ( priRegionHeight[ i ] * priResampleHeightNum[ i ] * MaxPicHeight[ pri_region_layer_id[ i ] ] ) ÷ ( priResampleHeightDenom[ i ] * PicHeightInLumaSamples[ pri_region_layer_id[ i ] ] * SubHeightC ) ) * SubHeightC}

[0146] When pri_target_pic_params_present_flag is equal to 1, the sum of ( pri_target_region_top_left_in_units_x[ i ] * priUnitSize ) and priTargetRegionWidth[ i ] shall be less than or equal to ( pri_target_pic_width_minus1 + 1 ), and the sum of ( pri_target_region_top_left_in_units_y[ i ] * priUnitSize ) and priTargetRegionHeight [ i ] shall be less than or equal to ( pri target pic height minus 1 + 1 ).

[0147] When reconstructing a target picture with luma sample array of size ( pri_target_pic_width_minus1 + 1 ) x ( pri target pic height minus 1 + 1 ), all luma sample values should be initialized to value 1 << ( BitDepthValY - 1 ) and chroma samples, if present, to 1 « ( BitDepthValC - 1 ).

[0148] The target picture reconstruction process should be performed, region by region, in increasing order of pri_region_id[ i ]. In this case, when a sample in the target picture relates to two or more regions, the reconstruction result from the region with a greater pri_region_id[ i ] overwrites the reconstruction result from the region with a smaller pri region id [ i ].4. Technical problems solved by disclosed technical solutions

[0149] An example design of the PRI SEI messages has the following limitations or problems:

[0150] First, the resampling ratio range is too large.

[0151] Second, pri_resampling_ratio_idx may be out of range and used without a specific value.

[0152] Third, two or more regions may have the same pri_region_id.

[0153] Fourth, two or more regions in a cropped decoded picture may overlap.

[0154] Fifth, a region may be indicated to be out of the picture boundary.

[0155] Sixth, the unit of the target picture's starting point is not clear.

[0156] Seventh, the target picture may not align with chroma samples.

[0157] Eighth, the resampling process may lead to results out of the target picture boundary.

[0158] Ninth, resampling information may be not indicated when there is no a specific target picture.

[0159] Tenth, in the design described in JVET-AN0367-vl, the requirement to send another PRI SEI message with pri_cancel_flag equal to 1 can be relaxed.

[0160] Eleventh, for a PRI SET message with pri_cancel_flag equal to 1, there is no layer association, the constraint for a PRI's location in JVET-AN0367-vl is incorrect.5. A listing of solutions and embodiments

[0161] To solve the above-described problems, methods as summarized below are disclosed. The aspects should be considered as examples to explain the general concepts and should not be interpreted in a narrow way. Furthermore, these examples can be applied individually or combined in any manner.1) To solve problem 1, in one example, a constraint on the value of resampling ratio is specified.a. In one example, it is specified that the resampling ratio shall be in the range of 14-M to N, inclusive, where M and N are positive integers.i. In one example, it is specified that the horizontal resampling ratio, i.e. the value of ( pri_resampling_width_num_minus1 [ i ] + 1 ) ÷ ( pri_resampling_width_denom_minus1 [ i ] + 1 ) shall be in the range of 1 ÷ M to N, inclusive.ii. In one example, it is specified that the vertical resampling ratio, i.e. the value of ( pri_resampling_width_num_minus1 [ i ] + 1 ) ÷ ( pri_resampling_height_denom_minus1[ i ] + 1 ) shall be in the range of 1 ÷ M to N, inclusive.b. In one example, both M and N are equal to 16.2) To solve problem 2, in one example, for pri_resampling_ratio_idx, the followings are specified.a. In one example, it is specified that the value of pri_resampling_ratio_idx shall be in the range of 0 to pri_num_resampling_ratios_minusl, inclusive.b. In one example, it is specified that, when not present, the value of pri_resampling_ratio_idx[ i ] is inferred to be equal to 0.3) To solve problem 3, in one example, it is specified that different regions shall have different region IDs.a. In one example, it is specified that for any two different integers i and j in the range of 0 to pri num regions minus 1, inclusive, pri region id [ i ] shall not be equal to pri region id [j ].4) To solve problem 4, in one example, one or more constraints are specified to disallow overlapping between any two regions.a. In one example, it is specified that any sample (x, y) in the cropped decoded picture of a specific layer shall belong to at most one region.5) To solve problem 5, in one example, one or more constraints are specified to disallow a region out of the picture boundary.a. In one example, it is specified that a region shall not be out of the boundary of the cropped decoded picture.i. In one example, it is specified that the sum of priRegionTopLeftXf i ] and priRegionWidth[ i ] shall be less than or equal to PicWidthTnLumaSamples[ pri_region_layer_id[ i ] ] and the sum of priRegionTopLeftY[ i ] and priRegionHeightf i ] shall be less than or equal to PicHeightInLumaSamples[ pri_region_layer_id[ i ] ].b. Alternatively, in one example, it is specified that a region shall not be out of the boundary of the decoded picture.i. In one example, it is specified that the sum of priRegionTopLeftX[ i ] and priRegionWidth[ i ] shall be less than or equal to MaxPicWidth[ pri_region_layer_id[ i ] ] and the sum of priRegionTopLeftY[ i ] and priRegionHeightf i ] shall be less than or equal to MaxPicHeight[pri_region_layer_id[ i ] ].6) To solve problem 6, in one example, the horizontal and vertical positions, respectively, of the top left sample position in units of the i-th region in the reconstructed target picture may be signalled in the PRI SEI message.a. In one example, the horizontal and vertical positions are coded in u(v) with the length, in bits, of the syntax elements equal to ( pri_region_size_len_minusl + 1 ).b. Alternatively, in one example, the horizontal and vertical positions, respectively, of the top left sample position in luma samples of the i-th region in the reconstructed target picture may be signalled in the PRI SEI message.i. In one example, the horizontal and vertical positions are coded in u(N), where N is a predefined positive integer.1. In one example, N is equal to 16.7) To solve problem 7, in one example, one or more constraints are specified to guarantee that the top left sample position of a region in the reconstructed target picture is aligned to chroma samples.a. In one example, it is specified that when pri_target_pic_params_present_flag is equal to 1, it is a requirement of bitstream conformance that both ( pri_target_region_top_left_x[ i ] * priUnitSize % SubWidthC ) and ( pri_target_region_top_left_yf i ] * priUnitSize % SubHeightC ) shall be equal to 0.b. Alternatively, in one example, it is specified that when pri_target_pic_params_present_flag is equal to 1, it is a requirement of bitstream conformance that both ( pri target region top left x[ i ] % SubWidthC ) and ( pri target region top left y[ i ] % SubHeightC ) shall be equal to 0.8) To solve problem 8, in one example, one or more constraints are specified to guarantee that the resampling area in the reconstructed target picture of a region is within the target picture boundary.a. In one example, it is specified that when pri_target_pic_params_present_flag is equal to 1, it is a requirement of bitstream conformance that the sum of ( pri target region top left x[ i ] * priUnilSize ) and priTargetRegionWidth[ i ] shall be less than or equal to ( pri_target_pic_width_minus1 + 1 ), and the sum of ( pri_target_region_top_left_y[ i ] * priUnitSize ) and priTargetRegionHeight[ i ] shall be less than or equal to ( pri target pic height minus 1 + 1 ).b. Alternatively, in one example, it is specified that when pri_target_pic_params_present_flag is equal to 1, it is a requirement of bitstream conformance that the sum of pri_target_region_top_left_x[ i ] and priTargetRegionWidth[ i ] shall be less than or equal to ( pri_target_pic_width_minus1 + 1 ) and the sum of pri_target_region_top_left_y[ i ] and priTargetRegionHeight[ i ] shall be less than or equal to ( pri_target_pic_height_minus1 + 1 ). ) To solve problem 9, in one example, one or more constraints may not be indicated when there is no target picture specified.a. In one example, when pri_target_pic_params_present_flag is equal to 0, pri_num_resampling_ratios_minusl may be not signalled.b. In one example, when pri_target_pic_params_present_flag is equal to 0, pri_resampling_width_num_minus1 may be not signalled.c. In one example, when pri_target_pic_params_present_flag is equal to 0, pri_resampling_width_denom_minusl may be not signalled.d. In one example, when pri target pic params present flag is equal to 0, pri_fixed_aspect_ratio_flag may be not signalled.e. In one example, when pri_target_pic_params_present_flag is equal to 0, pri resampling height num minus 1 may be not signalled.f. In one example, when pri_target_pic_params_present_flag is equal to 0, pri_resampling_height_denom_minus1 may be not signalled.g. In one example, when pri_target_pic_params_present_flag is equal to 0, pri_resampling_ratio_idx may be not signalled.10) To solve problem 10, in one example, for two PRI SEI messages, priSeiA and priSeiB, in different AUs in the CVS, priSeiA precedes priSeiB in output order and priSeiA has pri_persistence_flag equal to 0, it is allowed that there is no PRI SEI message with pri cancel flag equal to 1 between priSeiA and priSeiB, in output order.a. In one example, for two PRI SEI messages, priSeiA and priSeiB, in different AUs in the CVS, priSeiA precedes priSeiB in output order and priSeiA has pri persistence flag equal to 1, it is required that there is another PRI SEI message with pri_cancel_flag equal to 1 between priSeiA and priSeiB in output order.b. In one example, it is specified that when a PRI SEI message, priSeiA, and a PRI SEI message, priSeiB, are present in the different AUs in the CVS, priSeiB follows priSeiA in output order, pri_persistence_flag of priSeiA is equal to 1, and the ListOfAssociatedLayers of priSeiA and the ListOfAssociatedLayers of priSeiB are not identical but there exist m and n such that the value of ListOfAssociatedLayers[m] of priSeiA is equal to the value of ListOfAssociatedLayers[n] of priSeiB, there shall be another PRI SEI message priSeiC for which all of the following conditions are true:- The value of pri_cancel_flag of priSeiC is equal to 1.- priSeiC is present in a PU in the same layer as the PU that contains priSeiA.- priSeiC follows priSeiA in output order.- priSeiC precedes priSeiB in output order.11 ) To solve problem 11, in one example, one or more of the following aspects are specified:a. In one example, it is specified that when a PRI SEI message with pri cancel flag equal to 0 is present in an AU, the PRI SEI message shall be present in the PU that has layer identifier equal to the lowest value of pri_region_layer_id[ i ] for i in the range from 0 to pri num regions minus 1, inclusive.b. In addition, in one example, it is specified that, when a PRI SEI message with pri_cancel_flag equal to 1 is present in an AU, the PRI SEI message can be present in any PU of the AU. i. In one example, alternatively, it is specified that, when a PRI SEI message priSeiB with pri cancel flag equal to 1 is present in an AU, priSeiB can be present in any PU of the AU as long as there is another PRI SEI message priSeiA earlier in output order in the same CLVS and the persistence of the priSeiA is cancelled by priSeiB.6. Embodiments

[0162] Below are some example embodiments for the aspects summarized in section 5. Most relevant parts that have been added or modified are denoted by { { } }, and some of the deleted parts are denoted by [[[ ]]]. There may be some other changes that are editorial in nature and thus not highlighted.6.1 Embodiment 1

[0163] This embodiment corresponds to items 1, 1.a, 1.a.i, 1.a.ii, 1.b, 2, 2.a, 2.b, 3, 3.a, 4, 4.a, 5, 5.a, 5.a.i, 6, 6.a, 7, 7.a, 8, and 8.a.

[0164] The text changes are based on JVET-AK2006-v3.8.42 Packed regions information SEI message8.42.1 Packed regions information SEI message syntax8.42.2 Packed regions information SEI message semantics

[0165] pri_resampling_width_num_minus 1 [ i ] plus 1 and pri_resampling_width_denom_minus 1 [ i ] plus 1 specify the numerator and denominator, respectively, for the width resampling of the i-th resampling ratio. Both pri_resampling_width_num_minus1[ i ] and pri_resampling_width_denom_minus1[ i ] shall be in the range of 0 to 65535, inclusive.

[0166] When not present, the values of pri_resampling_ratio_width_num_minus1

[0000] and pri resampling ratio width denom minus 1

[0000] are inferred to be equal to 0.

[0167] {{The value of ( pri_resampling_width_num_minus1[ i ] + 1 ) 4- ( pri_resampling_width_denom_niinusl [ i ] + 1 ) shall be in the range of f - 16 to 16, inclusive. ) }

[0168] pri_fixed_aspect_ratio_flag[ i ] equal to 1 specifies that the pri_resampling_height_num_minus1 [ i ] and pri resampling height denom minusl[ i ] syntax elements are not present. pri_fixed_aspect_ratio_flag[ i ] equal to 0 specifies that the pri_resampling_height_num_minusl[ i ] and pri_resampling_height_denom_minus1[ i ] syntax elements are present.

[0169] pri_resampling_height_num_minusl[ i ] plus 1 and pri_resampling_height_denom_minus1[ i ] plus 1 specify the numerator and denominator, respectively, for the height resampling of the i-th resampling ratio. Both pri_resampling_height_num_minusl[ i 1 and pri_resampling_height_denom_minus1[ i ] shall be in the range of 0 to 65535, inclusive. When not present, the values of pri resamphng height num minusl[ i ] and pri_resampling_height_denom_minus 1 [ i ] are inferred to be equal to the pri_resampling_width_num_minus 1 [ i ] and pri_resampling_width_denom_minus1[ i ], respectively.

[0170] {{The value of (pri_resampling_height_num_minusl[ i ] + 1 ) 4- ( pri_resampling_height_denom_minus1[ i ] + 1 ) shall be in the range of 14- 16 to 16, inclusive. J }

[0171] pri_region_id[ i ] indicates the ID of the i-th region. When not present, the value of pri_region_id[ i ] is inferred to be equal to i.

[0172] {{For any two different integers i and j in the range of 0 to pri_num_regions_minus1, inclusive, pri_region_id[ i ] shall not be equal to pri_region_id[ j ].} }

[0173] pri_region_layer_id[ i ] specifies the layer id of the picture that the region information pri region top left in units x[ i ], pri region top left in units y[ i ], pri region width in units minuslf i ], pri_region_height_in_units_minusl[ i ] relate to. When not present, the value of pri_region_layer_id[ i ] is inferred to be equal to 0.

[0174] pri_region_is_a_layer_flag[ i ] equal to 1 specifies that the picture width and height in the layer of id pri_region_layer_id[ i ] are the same as the width and height of region of index i, and pri_region_top_left_in_units_x[ i ], pri_region_top_left_in_units_y[ i ], pri_region_width_in_units_minusl[ i ], pri_region_height_in_units_minusl[ i ] are not signaled. When not present, the value of pri_region_is_a_layer_flag[ i ] is inferred to be equal to 0.

[0175] pri_region_top_left_in_units_x[ i ] and pri_region_top_left_in_units_y[ i ] specify the horizontal and vertical positions, respectively, of the top left sample of the i-th region in units. The length of the syntax elements are pri_region_size_len_minusl + 1.

[0176] The variables priRegionTopLeftX[ i ] and priRegionTopLeftY[ i ], representing the horizontal and vertical positions, respectively, in luma samples of the i-th region in the cropped decoded picture with layer identifier equal to pri region layer id[ i ], are derived as follows:if(!pri_use_max_dimensions_flag ) {priRegionTopLeftX[ i ] = pri_region_top_left_in_units_x[ i ] * priUnitSize priRegionTopLeftY[ i ] = pri_region_top_left_in_units_y[ i ] * priUnitSize} else {priRegionTopLeftX[ i ] = ( pri_region_top_left_in_units_x[ i ] * priUnitSize * PicWidthInLumaSamples + MaxPicWidth / 2 ) / MaxWidthpriRegionTopLeftY[ i ] = ( pri_region_top_left_in_units_y[ i ] * priUnitSize * PicHeightInLumaSamples + MaxPicHeight / 2 ) / MaxHeight}

[0177] pri_region_width_in_units_minusl[ i ] plus 1 and pri_region_height_in_units_minus1[ i ] plus 1 specify the horizontal and vertical positions, respectively, of the width and height of the i-th region in units. The length of the syntax elements are pri region size len minus 1 + 1.

[0178] The variables priRegionWidth[ i ] and priRegionHeight[ i ], representing the width and height, respectively, in luma samples of the i-th region in the cropped decoded picture are derived as follows:if( !pri_use_max_dimensions_flag ) {priRegionWidth[ i ] = ( pri_region_width_in_units_minusl [ i ] + 1) * priUnitSize priRegionHeightf i ] = ( pri_region_height_in_units_minusl [ i ] + 1) * priUnitSize} else {priRegionWidth[ i ] = ( ( pri_region_width_in_units_minus1 [ i ] + 1) * priUnitSize * PicWidthInLumaSamples + MaxPicWidth / 2 ) / MaxWidthpriRegionHeight[ i ] = ( ( pri_region_height_in_units_minus1 [ i ] + 1) * priUnitSize * PicHeightInLumaSamples + MaxPicHeight / 2 ) / MaxHeight}

[0179] The variables SubWidthC and SubHeightC are derived from ChromaFormatldc as specified by Table 2 of the VSEI spec.

[0180] It is a requirement of bitstream conformance that priRegionWidth[ i ] % SubWidthC shall be equal to 0 and priRegionHeight[ i ] % SubHeightC shall be equal to 0.

[0181] { {It is a requirement of bitstream conformance that any sample (x, y) in the cropped decoded picture of a specific layer belongs to at most one region.

[0182] It is a requirement of bitstream conformance that the sum of priRegionTopLeftX[ i ] and priRegionWidth[ i ] shall be less than or equal to PicWidthInLumaSamples[ pri_region_layer_id[ i ] ] and the sum of priRegionTopLeftY[ i ] and priRegionHeight[ i ] shall be less than or equal to PicHeightInLumaSamples[ pri_region_layer_id[ i ] ].}}

[0183] pri_resampling_ratio_idx[ i ] specifies the index of the resampling ratio used for the i-th region. The length of the syntax element is Ceil( Log2( pri num resampling ratios minusl + 1 ) ). { {The value of pri resampling ratio idx[ i ] shall be in the range of 0 to pri num resampling ratios minusl, inclusive. When not present, the value of pri_resampling_ratio_idx[ i ] is inferred to be equal to 0.) }

[0184] The variables priResampleWidthNum[ i ], priResampleWidthDenom[ i ], priResampleHeightNum[ i ], and priResampleHeightDenom[ i ] are derived as follows:priResampleWidthNumf i ] = pri_resampling_width_num_minusl [ pri_resampling_ratio_idx[ i ] ] + 1 priResampleWidthDenomf i ] = pri resampling width denom minus 1[ pri resampling ratio idx[ i ] ] + 1 priResampleHeightNum[ i ] = pri_resampling_height_num_minus1[ pri_resampling_ratio_idx[ i ] ] + 1priResampleHeightDenom[ i ] =pri_resampling_height_denom_minus1[ pri_resampling_ratio_idx[ i ] ] + 1

[0185] pri_target_region_top_left_x[ i ] and pri_target_region_top_left_y[ i ], when present, indicate the horizontal and vertical positions, respectively, of the top left sample position in [[[luma samples units]]] of the i-th region in the reconstructed target picture. {{The length, in bits, of the syntax elements are pri_region_size_len_minusl + 1.}}

[0186] {{When pri_target_pic_params_present_flag is equal to 1, it is a requirement of bitstream conformance that both ( pri_target_region_top_left_x[ i ] * priUnitSize % SubWidthC ) and ( pri_target_region_top_left_y[ i ] * priUnitSize % SubHeightC ) shall be equal to 0.} }

[0187] The variables priTargetRegionWidth and priTargetHeight, representing the width and height, respectively, in luma samples of the resampled region in the reconstructed target picture, are derived as follows:priTargetRegionWidth = Round( ( priRegionWidth[ i ] * priResampleWidthNum[ i ] ) ÷ ( priResampleWidthDenom[ i ] * SubWidthC ) ) * SubWidthCpriTargetRegionHeight = Round( ( priRegionHeight[ i ] * priResampleHeightNum[ i ] ) ÷( priResampleHeightDenom[ i ] * SubHeightC ) ) * SubHeightC

[0188] {{When pri target pic params present flag is equal to 1, it is a requirement of bitstream conformance that the sum of ( pri_target_region_top_left_x[ i ] * priUnitSize ) and priTargetRegionWidth[ i ] shall be less than or equal to ( pri_target_pic_width_minus1 + 1 ), and the sum of ( pri_target_region_top_left_y[ i ] * priUnitSize ) and priTargetRegionHeight [ i ] shall be less than or equal to ( pri_target_pic_height_minus1 + 1 ).} }

[0189] When reconstructing a target picture with luma sample array of size (pri_target_pic_width_minus1 + 1) x (pri_target_pic_height_minus1 + 1), all luma sample values [[[are]]] {{should be}) initialized to value 1 « ( BitDepthY- 1) and chroma samples, if present, to 1 « ( BitDepthC- 1).6.2 Embodiment 2

[0190] This embodiment corresponds to items 9 and all its sub-items

[0191] The text changes are based on JVET-AL2006-v4.8.39.1 Packed regions information SEI message syntaxpacked_regions_info( payloadSize) Descriptor pri_cancel_flag u(1) if(!pri_cancel_flag ) {pri_persistence_flag u(1) pri_num_regions_minus1 ue(v) pri_multilayer_flag u(1) pri_use_max_dimensions_flag u(1) pri_log2_unit_size u(4) pri region size len minus 1 u(4) pri_region_id_present_flag u(1) pri_target_pic_params_present_flag u(1) if( pri_target_pic_params_present_flag ) {pri_target_pic_width_minus 1 u(16) pri_target_pic_height_minus 1 u(16) [[[ }]]]pri_num_resampling_ratios_minus1 ue(v) for( i = 1; i <= pri_num_resampling_ratios_minusl; i-H- ) {pri_resampling_width_num_minus1[ i ] ue(v) pri_resampling_width_denom_minus1[ i ] ue(v) pri_fixed_aspect_ratio_flag[ i ] u(1) if(!pri_fixed_aspect_ratio_flag[ i ] ) {pri_resampling_height_num_minus1[ i ] ue(v) pri_resampling_height_denom_minusl [ i ] ue(v) }{{ } }}}for( i = 0; i <= pri_num_regions_minusl; i++ ) {if( pri_region_id_present_flag )pri_region_id[ i ] ue(v) if( pri_multilayer_flag ) {pri_region_layer_id[ i ] ue(v) pri_region_is_a_layer_flag[ i ] u(1) ]if(!pri_region_is_a_layer_flag[ i ] ) {pri_region_top_left_in_units_x[ i ] u(v) pri_region_top_left_in_units_y[ i ] u(v) pri_region_width_in_units_minus1[ i ] u(v) pri_region_height_in_units_minusl[ i ] u(v) Jif( pri_num_resampling_ratios_minus1 >0{{ && pri-larget pic params present flag] ] )pri_resampling_ratio_idx[ i ] u(v) if( pri_target_pic_params_present_flag )pri_target_region_top_left_in_units_x[ i ] u(v) pri_target_region_top_left_in_units_y[ i ] u(v)}}}}6.3 Embodiments

[0192] This embodiment corresponds to items 10 and 11.

[0193] The text changes are based on JVET-AN0367-v1.8.39.2 Packed regions information SEI message semantics

[0194] The packed regions information (PR!) SEI message provides information regarding rectangular regions packed with the coded pictures of one or more layers. This information may optionally be used to reconstruct a target picture from the samples of the cropped decoded picture(s) corresponding to the regions described in this SEI message.

[0195] Use of this SEI message requires the definition of the following variables:- For each layer with a particular layer identifier value pri_region_layer_id[ i ], a picture width and picture height in units of luma samples, denoted herein hy PicWidthTnLumaSamples[ pri_region_layer_id[ i ] ] and PicHeightlnLumaS amplest pri_region layer id[ i ] ], respectively.- For each layer with a particular layer identifier value pri_region_layer_id[ i ], a maximum picture width and maximum picture height in units of luma samples, denoted herein by MaxPicWidth[ pri_region_layer_id[ i ] ] and MaxPicHeight[ pri_region_layer_id[ i ] ], respectively. - A chroma format indicator, denoted herein by ChromaFormatldc, as described in subclause 7.3.- A bit depth for the samples of the luma component, denoted herein by BitDepthValY, and a bit depth for the samples of the two associated chroma components, denoted herein by BitDepthValC.

[0196] NOTE - When ChromaFormatldc is equal to 0, BitDepthValC is not used.

[0197] The ListOfAssociatedLayers of a PRI SEI message is the list of layer identifiers containing unique values of pri_region_layer_id[ i ], in ascending order, for i in the range from 0 to pri_num_regions_minus1, inclusive, in the PRI SEI message.

[0198] When two or more PRI SET messages are present in an AU, both of the following apply:- All the PRI SEI messages that are present in the same PU shall have the same content.- When PRI SEI message priSeiA and PRI SEI message priSeiB are present in the same AU but in different PUs, the values in the ListOfAssociatedLayers of seiPriA and seiPriB shall be mutually exclusive.

[0199] When PRI SEI message priSeiA and PRI SEI message priSeiB are present in the different AU in the CVS, priSeiB follows priSeiA in output order, { {pri_persistence_flag of priSeiA is equal to 1,)} and the ListOfAssociatedLayers of priSeiA and the ListOfAssociatedLayers of priSeiB are not identical but there is m and n such that the value of ListOfAssociatedLayers[m] of priSeiA is equal to the value of ListOfAssociatedLayers[n] of priSeiB, it is constrained that there shall be another PRI SEI message priSeiC that satisfies all of the following:- The value of pri_cancel_flag of priSeiC is equal to 1.- priSeiC is present in a PU in the same layer as the PU that contains seiPriA.- priSeiC follows priSeiA in output order.- priSeiC precedes priSeiB in output order.

[0200] When a PRI SEI message { {with pri_cancel_flag equal to 0}} is present in an AU, the PRI SEI message shall be present in the PU which has layer identifier equals to the lowest value of pri region layer id[ i ] for i in the range from 0 to pri_num_regions_minusL inclusive.

[0201] { { When a PRI SEI message with pri cancel flag equal to 1 is present in an AU, the PRI SEI message can be present in any PU of the AU. } j

[0202] pri_cancel_flag equal to 1 indicates that the SEI message cancels the persistence of any previous packed regions information SEI message, in output order, in the same CLVS. pri_cancel_flag equal to 0 indicates that packed regions information follows.T0203] For two SEI messages seiA and seiB in two different AUs, seiB is said to be following seiA in output order when any picture in the AU containing seiB follows any picture in the AU containing seiA in output order.

[0204] pri persistence flag specifies the persistence of the packed regions information SEI message.

[0205] pri_persistence_flag equal to 0 specifies that the packed regions information applies to the current AU only.

[0206] pri_persistence_flag equal to 1 specifies that the packed regions information SEI message in the current CLVS applies to pictures in the the current AU and persists for pictures in all subsequent AUs in output order in the current CVS until an AU, when present, that follows the current AU in output order and contains a packed regions information SEI message in the same CLVS.

[0207] NOTE - The pictures to which the persistence of PRI SEI message applies to are pictures with layer identifier equal to one of the value of pri_region_layer_id[ j ] and layer identifier of the PU where the SEI message is present7. References[1] Rec. ITU-T H.265 | ISO / IEC 23008-2, “High efficiency video coding”.[2] Rec. ITU-T H.266 | ISO / IEC 23090-3, “Versatile Video Coding”.[3] Rec. ITU-T Rec. H.274 | ISO / IEC 23002-7, “Versatile Supplemental Enhancement Information Messages for Coded Video Bitstreams”.[4] J. Boyce, J. Chen, S. Deshpande, M. M. Hannuksela, S. McCarthy, G. J. Sullivan, H. Tan, Y.-K. Wang (editors), “Additional SEI messages for VSEI version 4 (Draft 5),” JVET output document JVET-AK2006- v3, publicly available online herein: https: / / www.jvet-expei1s.org / doc_end_user / documenfs / 37_Geneva / wgl lZJVET-AK2006-v3.zip.[5] G. J. Sullivan, B. Bross, M. M. Hannuksela, Y.-K. Wang (editors), “Additions and corrections for VVC version 4 (Draft ll),” JVET output document JVET-AK2005-v2, publicly available online herein: https: / / www.jvet-experts.org / doc_end_user / documents / 37_Geneva / wgll / JVET-AK2005-v2.zip.

[0208] FIG. 1 is a block diagram showing an example video processing system 4000 in which various techniques disclosed herein may be implemented. Various implementations may include some or all of the components of the system 4000. The system 4000 may include input 4002 for receiving video content. The video content may be received in a raw or uncompressed format, e.g., 8 or 10 bit multi-component pixel values, or may be in a compressed or encoded format. Tire input 4002 may represent a network interface, a peripheral bus interface, or a storage interface. Examples of network interface include wired interfaces such as Ethernet, passive optical network (PON), etc. and wireless interfaces such as wireless fidelity (Wi-Fi) or cellular interfaces.

[0209] The system 4000 may include a coding component 4004 that may implement the various coding or encoding methods described in the present disclosure. The coding component 4004 may reduce the average bitrate of video from the input 4002 to the output of the coding component 4004 to produce a coded representation ofthe video. The coding techniques are therefore sometimes called video compression or video transcoding techniques. The output of the coding component 4004 may be either stored, or transmitted via a communication connected, as represented by the component 4006. The stored or communicated bitstream (or coded) representation of the video received at the input 4002 may be used by a component 4008 for generating pixel values or displayable video that is sent to a display interface 4010. The process of generating user-viewable video from the bitstream representation is sometimes called video decompression. Furthermore, while certain video processing operations are referred to as “coding” operations or tools, it will be appreciated that the coding tools or operations are used at an encoder and corresponding decoding tools or operations that reverse the results of the coding will be performed by a decoder.

[0210] Examples of a peripheral bus interface or a display interface may include universal serial bus (USB) or high definition multimedia interface (HDMI) or Displayport, and so on. Examples of storage interfaces include serial advanced technology attachment (SATA), peripheral component interconnect (PCI), integrated drive electronics (IDE) interface, and the like. The techniques described in the present disclosure may be embodied in various electronic devices such as mobile phones, laptops, smartphones or other devices that are capable of performing digital data processing and / or video display.

[0211] FIG. 2 is a block diagram of an example video processing apparatus 4100. The apparatus 4100 may be used to implement one or more of the methods described herein. The apparatus 4100 may be embodied in a smartphone, tablet, computer, Internet of Things (loT) receiver, and so on. The apparatus 4100 may include one or more processors 4102, one or more memories 4104 and video processing circuitry 4106. The processor(s) 4102 may be configured to implement one or more methods described in the present disclosure. The memory (memories) 4104 may be used for storing data and code used for implementing the methods and techniques described herein. The video processing circuitry 4106 may be used to implement, in hardware circuitry, some techniques described in the present disclosure. In some embodiments, the video processing circuitry 4106 may be at least partly included in the processor 4102, e.g., a graphics co-processor.

[0212] FIG. 3 is a flowchart for an example method 4200 of video processing. The method 4200 to specify a horizontal position and a vertical position of a top left sample of an i-th region in a packed regions information (PRI) supplemental enhancement information (SEI) message at step 4202. A conversion is performed between a visual media data and a bitstream based on the horizontal position and the vertical position of the top left sample of the i-th region in the PRI SEI message at step 4204. The conversion may include encoding at an encoder, decoding at a decoder, or combinations thereof.

[0213] It should be noted that the method 4200 can be implemented in an apparatus for processing video data comprising a processor and a non-transitory memory' with instructions thereon, such as video encoder 4400, video decoder 4500, and / or encoder 4600. Tn such a case, the instructions upon execution by the processor, cause the processor to perform the method 4200. Further, the method 4200 can be performed by a non-transitory computer readable medium comprising a computer program product for use by a video coding device. Thecomputer program product comprises computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the video coding device to perform the method 4200.T0214] FIG. 4 is a block diagram that illustrates an example video coding system 4300 that may utilize the techniques of this disclosure. The video coding system 4300 may include a source device 4310 and a destination device 4320. Source device 4310 generates encoded video data which may be referred to as a video encoding device. Destination device 4320 may decode the encoded video data generated by source device 4310 which may be referred to as a video decoding device.

[0215] Source device 4310 may include a video source 4312, a video encoder 4.314, and an input / output (I / O) interface 4316. Video source 4312 may include a source such as a video capture device, an interface to receive video data from a video content provider, and / or a computer graphics system for generating video data, or a combination of such sources. The video data may comprise one or more pictures. Video encoder 4314 encodes the video data from video source 4312 to generate a bitstream. The bitstream may include a sequence of bits that form a coded representation of the video data. The bitstream may include coded pictures and associated data. The coded picture is a coded representation of a picture. The associated data may include sequence parameter sets, picture parameter sets, and other syntax structures. I / O interface 4316 may include a modulator / demodulator (modem) and / or a transmitter. The encoded video data may be transmitted directly to destination device 4320 via I / O interface 4316 through network 4330. The encoded video data may also be stored onto a storage medium / server 4340 for access by destination device 4320.

[0216] Destination device 4320 may include an I / O interface 4326, a video decoder 4324, and a display device 4322. I / O interface 4326 may include a receiver and / or a modem. I / O interface 4326 may acquire encoded video data from the source device 4310 or the storage medium / server 4340. Video decoder 4324 may decode the encoded video data. Display device 4322 may display the decoded video data to a user. Display device 4322 may be integrated with the destination device 4320, or may be external to destination device 4320, which can be configured to interface with an external display device.

[0217] Video encoder 4314 and video decoder 4324 may operate according to a video compression standard, such as the High Efficiency Video Coding (HEVC) standard, Versatile Video Coding (VVC) standard and other current and / or further standards.

[0218] FIG.5 is a block diagram illustrating an example of video encoder 4400, which may be video encoder 4314 in the system 4300 illustrated in FIG. 4. Video encoder 4400 may be configured to perform any or all of the techniques of this disclosure. The video encoder 4400 includes a plurality of functional components. The techniques described in this disclosure may be shared among the various components of video encoder 4400. In some examples, a processor may be configured to perform any or all of the techniques described in this disclosure.

[0219] The functional components of video encoder 4400 may include a partition unit 4401, a prediction unit 4402 which may include a mode select unit 4403, a motion estimation unit 4404, a motion compensation unit4405, an intra prediction unit 4406, a residual generation unit 4407, a transform processing unit 4408, a quantization unit 4409, an inverse quantization unit 4410, an inverse transform unit 4411, a reconstruction unit 4412, a buffer 4413, and an entropy encoding unit 4414.T0220] In other examples, video encoder 4400 may include more, fewer, or different functional components. In an example, prediction unit 4402 may include an intra block copy (IBC) unit. The IBC unit may perform prediction in an IBC mode in which at least one reference picture is a picture where the current video block is located.

[0221] Furthermore, some components, such as motion estimation unit 4404 and motion compensation unit 4405 may be highly integrated, but are represented in the example of video encoder 4400 separately for purposes of explanation.

[0222] Partition unit 4401 may partition a picture into one or more video blocks. Video encoder 4400 and video decoder 4500 may support various video block sizes.

[0223] Mode select unit 4403 may select one of the coding modes, intra or inter, e.g., based on error results, and provide the resulting intra or inter coded block to a residual generation unit 4407 to generate residual block data and to a reconstruction unit 4412 to reconstruct the encoded block for use as a reference picture. In some examples, mode select unit 4403 may select a combination of intra and inter prediction (CIIP) mode in which the prediction is based on an inter prediction signal and an intra prediction signal. Mode select unit 4403 may also select a resolution for a motion vector (e.g., a sub-pixel or integer pixel precision) for the block in the case of inter prediction.

[0224] To perform inter prediction on a current video block, motion estimation unit 4404 may generate motion information for the current video block by comparing one or more reference frames from buffer 4413 to the current video block. Motion compensation unit 4405 may determine a predicted video block for the current video block based on the motion information and decoded samples of pictures from buffer 4413 other than the picture associated with the current video block.

[0225] Motion estimation unit 4404 and motion compensation unit 4405 may perform different operations for a current video block, for example, depending on whether the current video block is in an I slice, a P slice, or a B slice.

[0226] Tn some examples, motion estimation unit 4404 may perform uni-directional prediction for the current video block, and motion estimation unit 4404 may search reference pictures of list 0 or list 1 for a reference video block for the current video block. Motion estimation unit 4404 may then generate a reference index that indicates the reference picture in list 0 or list 1 that contains the reference video block and a motion vector that indicates a spatial displacement between the current video block and the reference video block. Motion estimation unit 4404 may output the reference index, a prediction direction indicator, and the motion vector as the motion information of the current video block. Motion compensation unit 4405 may generate the predicted video blockof the current block based on the reference video block indicated by the motion information of the current video block.

[0227] In other examples, motion estimation unit 4404 may perform bi-directional prediction for the current video block, motion estimation unit 4404 may search the reference pictures in list 0 for a reference video block for the current video block and may also search the reference pictures in list 1 for another reference video block for the current video block. Motion estimation unit 4404 may then generate reference indexes that indicate the reference pictures in list 0 and list 1 containing the reference video blocks and motion vectors that indicate spatial displacements between the reference video blocks and the current video block. Motion estimation unit 4404 may output the reference indexes and the motion vectors of the current video block as the motion information of the current video block. Motion compensation unit 4405 may generate the predicted video block of the current video block based on the reference video blocks indicated by the motion information of the current video block.

[0228] Tn some examples, motion estimation unit 4404 may output a full set of motion information for decoding processing of a decoder. In some examples, motion estimation unit 4404 may not output a full set of motion information for the current video. Rather, motion estimation unit 4404 may signal the motion information of the current video block with reference to the motion information of another video block. For example, motion estimation unit 4404 may determine that the motion information of the current video block is sufficiently similar to the motion information of a neighboring video block.

[0229] In one example, motion estimation unit 4404 may indicate, in a syntax structure associated with the current video block, a value that indicates to the video decoder 4500 that the current video block has the same motion information as another video block.

[0230] In another example, motion estimation unit 4404 may identify, in a syntax structure associated with the current video block, another video block and a motion vector difference (MVD). The motion vector difference indicates a difference between the motion vector of the current video block and the motion vector of the indicated video block. The video decoder 4500 may use the motion vector of the indicated video block and the motion vector difference to determine the motion vector of the current video block.

[0231] As discussed above, video encoder 4400 may predictively signal the motion vector. Two examples of predictive signaling techniques that may be implemented by video encoder 4400 include advanced motion vector prediction (AM VP) and merge mode signaling.

[0232] Intra prediction unit 4406 may perform intra prediction on the current video block. When intra prediction unit 4406 performs intra prediction on the current video block, intra prediction unit 4406 may generate prediction data for the current video block based on decoded samples of other video blocks in the same picture. The prediction data for the current video block may include a predicted video block and various syntax elements.

[0233] Residual generation unit 4407 may generate residual data for the current video block by subtracting the predicted video block(s) of the current video block from the current video block. The residual data of thecurrent video block may include residual video blocks that correspond to different sample components of the samples in the current video block.

[0234] In other examples, there may be no residual data for the current video block for the current video block, for example in a skip mode, and residual generation unit 4407 may not perform the subtracting operation.

[0235] Transform processing unit 4408 may generate one or more transform coefficient video blocks for the current video block by applying one or more transforms to a residual video block associated with the current video block.

[0236] After transform processing unit 4408 generates a transform coefficient video block associated with the current video block, quantization unit 4409 may quantize the transform coefficient video block associated with the current video block based on one or more quantization parameter (QP) values associated with the current video block.

[0237] Inverse quantization unit 4410 and inverse transform unit 4411 may apply inverse quantization and inverse transforms to the transform coefficient video block, respectively, to reconstruct a residual video block from the transform coefficient video block. Reconstruction unit 4412 may add the reconstructed residual video block to corresponding samples from one or more predicted video blocks generated by the prediction unit 4402 to produce a reconstructed video block associated with the current block for storage in the buffer 4413.

[0238] After reconstruction unit 4412 reconstructs the video block, the loop filtering operation may be performed to reduce video blocking artifacts in the video block.

[0239] Entropy encoding unit 4414 may receive data from other functional components of the video encoder 4400. When entropy encoding unit 4414 receives the data, entropy encoding unit 4414 may perform one or more entropy encoding operations to generate entropy encoded data and output a bitstream that includes the entropy encoded data.

[0240] FIG. 6 is a block diagram illustrating an example of video decoder 4500 which may be video decoder 4324 in the system 4300 illustrated in FIG. 4. The video decoder 4500 may be configured to perform any or all of the techniques of this disclosure. In the example shown, the video decoder 4500 includes a plurality of functional components. The techniques described in this disclosure may be shared among the various components of the video decoder 4500. In some examples, a processor may be configured to perform any or all of the techniques described in this disclosure.

[0241] In the example shown, video decoder 4500 includes an entropy decoding unit 4501, a motion compensation unit 4502, an intra prediction unit 4503, an inverse quantization unit 4504, an inverse transformation unit 4505, a reconstruction unit 4506, and a buffer 4507. Video decoder 4500 may, in some examples, perform a decoding pass generally reciprocal to the encoding pass described with respect to video encoder 4400.

[0242] Entropy decoding unit 4501 may retrieve an encoded bitstream. The encoded bitstream may include entropy coded video data (e.g., encoded blocks of video data). Entropy decoding unit 4501 may decode theentropy coded video data, and from the entropy decoded video data, motion compensation unit 4502 may determine motion information including motion vectors, motion vector precision, reference picture list indexes, and other motion information. Motion compensation unit 4502 may, for example, determine such information by performing the AMVP and merge mode.

[0243] Motion compensation unit 4502 may produce motion compensated blocks, possibly performing interpolation based on interpolation filters. Identifiers for interpolation filters to be used with sub-pixel precision may be included in the syntax elements.

[0244] Motion compensation unit 4502 may use interpolation filters as used by video encoder 4400 during encoding of the video block to calculate interpolated values for sub-integer pixels of a reference block. Motion compensation unit 4502 may determine the interpolation filters used by video encoder 4400 according to received syntax information and use the interpolation filters to produce predictive blocks.

[0245] Motion compensation unit 4502 may use some of the syntax information to determine sizes of blocks used to encode frame(s) and / or slice(s) of the encoded video sequence, partition information that describes how each macroblock of a picture of the encoded video sequence is partitioned, modes indicating how each partition is encoded, one or more reference frames (and reference frame lists) for each inter coded block, and other information to decode the encoded video sequence.

[0246] Intra prediction unit 4503 may use intra prediction modes for example received in the bitstream to form a prediction block from spatially adjacent blocks. Inverse quantization unit 4504 inverse quantizes, i.e., dequantizes, the quantized video block coefficients provided in the bitstream and decoded by entropy decoding unit 4501. Inverse transform unit 4505 applies an inverse transform.

[0247] Recon struction unit 4506 may sum the residual blocks with the corresponding prediction blocks generated by motion compensation unit 4502 or intra prediction unit 4503 to form decoded blocks. If desired, a deblocking filter may also be applied to filter the decoded blocks in order to remove blockiness artifacts. The decoded video blocks are then stored in buffer 4507, which provides reference blocks for subsequent motion compensation / intra prediction and also produces decoded video for presentation on a display device.

[0248] FIG. 7 is a schematic diagram of an example encoder 4600. The encoder 4600 is suitable for implementing the techniques of VVC. The encoder 4600 includes three in-loop filters, namely a deblocking filter (DF) 4602, a sample adaptive offset (SAG) 4604, and an adaptive loop filter (ALF) 4606. Unlike the DF 4602, which uses predefined filters, the SAO 4604 and the ALF 4606 utilize the original samples of the current picture to reduce the mean square errors between the original samples and the reconstructed samples by adding an offset and by applying a finite impulse response (FIR) filter, respectively, with coded side information signaling the offsets and filter coefficients. The ALF 4606 is located at the last processing stage of each picture and can be regarded as a tool trying to catch and fix artifacts created by the previous stages.

[0249] The encoder 4600 further includes an intra prediction component 4608 and a motion estimation / compensation (ME / MC) component 4610 configured to receive input video. The intra predictioncomponent 4608 is configured to perform intra prediction, while the ME / MC component 4610 is configured to utilize reference pictures obtained from a reference picture buffer 4612 to perform inter prediction. Residual blocks from inter prediction or intra prediction are fed into a transform (T) component 4614 and a quantization (Q) component 4616 to generate quantized residual transform coefficients, which are fed into an entropy coding component 4618. The entropy coding component 4618 entropy codes the prediction results and the quantized transform coefficients and transmits the same toward a video decoder (not shown). Quantization components output from the quantization component 4616 may be fed into an inverse quantization (IQ) components 4620, an inverse transform component 4622, and a reconstruction (REC) component 4624. The REC component 4624 is able to output images to the DF 4602, the SAO 4604, and the ALF 4606 for filtering prior to those images being stored in the reference picture buffer 4612.

[0250] A listing of solutions preferred by some examples is provided next.

[0251] The following solutions show examples of techniques discussed herein.

[0252] 1. A method for processing media data comprising: determining for a Packed Regions Information (PR!) supplemental enhancement information (SEI) message specifies a constraint on a value of a resampling ratio; and performing a conversion between a visual media data and a bitstream based on the PRI SEI message.

[0253] 2. The method of solution 1, wherein the resampling ratio shall be in the range of l-M to N, inclusive, where M and N tire positive integers.

[0254] 3. The method of any of solutions 1-2, wherein the horizontal resampling ratio shall be in a range of l - M to N, inclusive, and wherein the horizontal resampling ratio is determined as a value of pri_resampling_width_num_minus1[ i ] + 1 ) 4- ( pri_resampling_width_denom_minus1[ i ] + 1 ), where pri_resampling_width_num_minus1 is a PR! resampling width numerator minus one and pri resampling width denom minus 1 is a PRI resampling width denominator minus one.

[0255] 4. The method of any of solutions 1 -3, wherein a vertical resampling ratio shall be in the range of 1 4- M to N, inclusive, and wherein the vertical resampling ratio is determined as a value of (pri_resampling_width_num_minus1[ i ] + 1 ) - ( pri_resampling_height_denom_minus1[ i ] + 1 ), where pri_resampling_height_denom_minus1 is a PRI resampling height denominator minus one.

[0256] 5. The method of any of solutions 1-4, wherein both M and N are equal to 16.

[0257] 6. The method of any of solutions 1-5, wherein a value of PRI resampling ratio index (pri_resampling_ratio_idx) shall be in the range of 0 to PRI number of resampling rations minus one (pri_num_resampling_ratios_minusl), inclusive, and wherein when not present, the value of pri resampling ratio idx[ i ] is inferred to be equal to 0.

[0258] 7. The method of any of solutions 1-6, wherein different regions shall have different region IDs.

[0259] 8. The method of any of solutions 1-7, wherein for any two different integers i and j in a range of 0 to PRI number of regions minus one (pri_num_regions_minusl), inclusive, PRI region identifier (pri_region_id| i ]) shall not be equal to pri_region_id[ j ].

[0260] 9. The method of any of solutions 1-8, wherein constraints are specified to disallow overlapping between any two regions, or wherein any sample (x, y) in a cropped decoded picture of a specific layer shall belong to at most one region.

[0261] 10. The method of any of solutions 1-9, wherein one or more constraints are specified to disallow a region out of a picture boundary, or wherein a region shall not be out of the boundary of a cropped decoded picture, or wherein a region shall not be out of a boundary of a decoded picture.

[0262] 11. The method of any of solutions 1-10, wherein the sum of PRI region top left x axis (priRegionTopLeftX[ i ]) and PRI region width (priRegionWidth[ i ]) shall be less than or equal to icture width in luma samples for a PRI region layer identifier (PicWidthInLumaSamples[ pri_region_layer_id[ i ] ]) and the sum of PRI region top left y axis (priRegionTopLeftY[ i ]) and PRI region height (priRegionHeight[ i ]) shall be less than or equal to picture height in luma samples for a PRI region layer identifier (PicHeightInLumaSamples[ pri region layer id[ i ] ]), or wherein the sum of priRegionTopLeftX[ i ] and priRegionWidth[ i ] shall be less than or equal to maximum picture width for a PRI region layer identifier (MaxPicWidth[ pri_region_layer_id[ i ] ]) and the sum of priRegionTopLeftY[ i ] and priRegionHeight[ i ] shall be less than or equal to maximum picture height for a PRI region layer identifier (MaxPicHeight[ pri_region_layer_id[ i ] ]).

[0263] 12. The method of any of solutions 1-11, wherein horizontal and vertical positions, respectively, of a top left sample position in units of an i-th region in a reconstructed target picture are signalled in the PRI SEI message.

[0264] 13. The method of any of solutions 1-12, wherein horizontal and vertical positions are coded in unsigned integer of variable length (u(v)) with a length, in bits, of syntax elements equal to PRI region size length minus one plus one (pri region size len minus 1 + 1 ), or wherein the horizontal and vertical positions, respectively, of the top left sample position in luma samples of the i-th region in the reconstructed target picture are signalled in the PRI SEI message, or wherein the horizontal and vertical positions are coded in unsigned integer of length N (u(N)), where N is a predefined positive integer, or wherein N is equal to 16.

[0265] 14. The method of any of solutions 1-13, wherein one or more constraints are specified to guarantee that a top left sample position of a region in a reconstructed target picture is aligned to chroma samples.

[0266] 15. The method of any of solutions 1 14, wherein when PRI target picture parameters present flag (pri target pic params present flag) is equal to 1, both ( pri_target_region_top_left_x[ i ] * priUnitSize % SubWidthC ) and ( pri_targel_region_lop_lefl_y| i ] * priUnitSize % SubHeightC ) shall be equal to 0, wherein pri_target_region_top_left_x is a PRI target region top left x axis, priUnitSize is a PRI unit size, SubWidthC is a sub-width chroma component, pri_target_region_top_left_y is a PRI target region top left y axis, and SubHeightC is a sub-height chroma component.T0267] 16. The method of any of solutions 1-15, wherein when pri_target_pic_params_present_flag is equal to 1, both ( pri_target_region_top_left_x[ i ] % SubWidthC ) and ( pri_target_region_top_left_y[ i ] % SubHeightC ) shall be equal to 0.

[0268] 17. The method of any of solutions 1-16, wherein one or more constraints are specified to guarantee that a resampling area in a reconstructed target picture of a region is within a target picture boundary.

[0269] 18. The method of any of solutions 1-17, wherein when pri_target_pic_params_present_flag is equal to 1, a sum of ( pri_target_region_top_left_x[ i ] * priUnitSize ) and priTargetRegionWidth[ i ] shall be less than or equal to ( pri_target_pic_width_minus1 + 1 ), and a sum of ( pri_target_region_top_left_y[ i ] * priUnitSize ) and priTargetRegionHeight[ i ] shall be less than or equal to ( pri_target_pic_height_minus1 + 1 ) where priTargetRegionWidth is a PRI target region width, pri_target_pic_width_minus1 is a PRI target picture width minus one, priTargetRegionHeight is a PRI target region height, andpri_target_pic_height_minus1 is a PRI target picture height minus one.

[0270] 19. The method of any of solutions 1-18, wherein when pri_target_pic_params_present_flag is equal to 1, a sum of pri_target_region_top_left_x[ i ] and priTargetRegionWidth[ i ] shall be less than or equal to ( pri_target_pic_width_minus1 + 1 ) and a sum of pri_target_region_top_left_y[ i ] and priTargetRegionHeight[ i ] shall be less than or equal to ( pri_target_pic_height_minus1 + 1 ).

[0271] 20. The method of any of solutions 1-19, wherein the conversion includes encoding the visual media data into the bitstream.

[0272] 21. The method of any of solutions 1-19, wherein the conversion includes decoding the visual media data from the bitstream.

[0273] 22. An apparatus for processing video data comprising: a processor; and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to perform the method of any of solutions 1-21.

[0274] 23. A non-transitory computer readable medium comprising a computer program product for use by a video coding device, the computer program product comprising computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the video coding device to perform the method of any of solutions 1-21.

[0275] 24. A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises: determining for a Packed Regions Information (PRI) supplemental enhancement information (SEI) message specifies a constraint on a value of a resampling ratio; and generating a bitstream based on the determining.

[0276] 25. A method for storing bitstream of a video comprising: determining for a Packed Regions Information (PRI) supplemental enhancement information (SEI) message specifies a constraint on a value of a resampling ratio; generating a bitstream based on the determining; and storing the bitstream in a non-transitory computer-readable recording medium.

[0277] 26. A method, apparatus, or system described in the present disclosure.

[0278] In the solutions described herein, an encoder may conform to the format rule by producing a coded representation according to the format rule. In the solutions described herein, a decoder may use the format rule to parse syntax elements in the coded representation with the knowledge of presence and absence of syntax elements according to the format rule to produce decoded video.

[0279] In the present disclosure, the term “video processing” may refer to video encoding, video decoding, video compression or video decompression. For example, video compression algorithms may be applied during conversion from pixel representation of a video to a corresponding bitstream representation or vice versa. The bitstream representation of a current video block may, for example, correspond to bits that are either co-located or spread in different places within the bitstream, as is defined by the syntax. For example, a macroblock may be encoded in terms of transformed and coded error residual values and also using bits in headers and other fields in the bitstream. Furthermore, during conversion, a decoder may parse a bitstream with the knowledge that some fields may be present, or absent, based on the determination, as is described in the above solutions. Similarly, an encoder may determine that certain syntax fields are or are not to be included and generate the coded representation accordingly by including or excluding the syntax fields from the coded representation.

[0280] Tire disclosed and other solutions, examples, embodiments, modules and the functional operations described in this disclosure can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this disclosure and their structural equivalents, or in combinations of one or more of them. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer readable medium for execution by, or to control the operation of, data processing apparatus. The computer readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter effecting a machine -readable propagated signal, or a combination of one or more them. The term “data processing apparatus” encompasses all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The apparatus can include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagated signal is an artificially generated signal, e.g., a machine -generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to suitable receiver apparatus.

[0281] A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or morescripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

[0282] The processes and logic flows described in this disclosure can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an field programmable gate array (FPGA) or an application specific integrated circuit (ASIC).

[0283] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random-access memory or both. The essential elements of a computer are a processor for performing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. However, a computer need not have such devices. Computer readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory' devices, including by way of example semiconductor memory devices, e.g., erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and compact disc read-only memory (CD ROM) and digital versatile disc-read only memory (DVD-ROM) disks. The processor and the memory' can be supplemented by, or incorporated in, special purpose logic circuitry.

[0284] While the present disclosure contains many specifics, these should not be construed as limitations on the scope of any subject matter or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular techniques. Certain features that are described in the present disclosure in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0285] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, the separation of varioussystem components in the embodiments described in the present disclosure should not be understood as requiring such separation in all embodiments.

[0286] Only a few implementations and examples are described and other implementations, enhancements and variations can be made based on what is described and illustrated in the present disclosure.

[0287] A first component is directly coupled to a second component when there are no intervening components, except for a line, a trace, or another medium between the first component and the second component. The first component is indirectly coupled to the second component when there are intervening components other than a line, a trace, or another medium between the first component and the second component. The term “coupled” and its variants include both directly coupled and indirectly coupled. The use of the term “about” means a range including ±10% of the subsequent number unless otherwise stated.

[0288] While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented.

[0289] In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled may be directly connected or may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.

Claims

CLAIMSWhat is claimed is:

1. A method for processing media data, comprising:determining to specify a horizontal position and a vertical position of a top left sample of an i-th region in a packed regions information (PRI) supplemental enhancement information (SEI) message; and performing a conversion between a visual media data and a bitstream based on the horizontal position and the vertical position of the top left sample of the i-th region in the PRI SEI message.

2. The method of claim 1, wherein the horizontal position and the vertical position are each coded using an unsigned integer using a variable number of bits (u(v)).

3. The method of claim 2, wherein a number of bits used to code the horizontal position and the vertical position is specified by pri_region_size_len_minusl plus 1.

4. The method of claim 1, wherein the horizontal position and the vertical position of the top left sample of the i-th region in a reconstructed target picture are included in the PRI SEI message.

5. The method of claim 4, wherein the horizontal position and the vertical position are each coded using an unsigned integer using N bits (u(N)), where N is a positive integer.

6. The method of claim 5, wherein N is equal to 16.

7. The method of any of claims 1-6, wherein the bitstream includes constraints to ensure that the horizontal position and the vertical position of the top left sample of the i-th region are aligned to chroma samples.

8. The method of claim 7, wherein, when pri_target_pic_params_present_flag is equal to 1, a value of ( pri_target_region_top_left_in_units_x[ i ] * priUnitSize % SubWidthC ) and a value of ( pri_target_region_top_left_in_units_y[ i ] * priUnitSize % SubHeightC ) shall be equal to 0.

9. The method of claim 8, wherein pri_target_region_top_left_in_units_x[ i ] and pri_target_region_top_left_in_units_y[ i ] indicate horizontal and vertical positions, respectively, of a top left sample position, in units of priUnitSize luma samples, of an i-th region in a reconstructed target picture, wherein priUnitSize represents a PRI unit size, wherein SubWidthC represents a chroma scaling factor in a horizontal direction, and wherein SubHeightC represents a chroma scaling factor in a vertical direction.

10. The method of claim 7, wherein, when pri_target_pic_params_present_flag is equal to 1, both ( pri_target_region_top_left_x[ i ] % SubWidthC ) and ( pri_target_region_top_left_y[ i ] % SubHeightC ) shall be equal to 0.

11. The method of claim 10, wherein the pri_target_region_top_left_x[ i ] and the pri_target_region_top_left_y[ i ] indicate horizontal and vertical positions, respectively, of a top left sample position, in units of priUnitSize luma samples, of an i-th region in a reconstructed target picture, wherein SubWidthC represents a chroma scaling factor in a horizontal direction, and wherein SubHeightC represents a chroma scaling factor in a vertical direction.

12. The method of any of claims 1-11, wherein the bitstream includes constraints to ensure that a resampling area in a reconstructed target picture of a region is within a target picture boundary.

13. The method of claim 12, wherein, when pri_target_pic_params_present_flag is equal to 1, a sum of ( pri_target_region_top_left_x[ i ] * priUnitSize ) and priTargetRegionWidth[ i ] shall be less than or equal to ( pri_target_pic_width_minus1 + 1 ), and a sum of ( pri_target_region_top_left_y[ i ] * priUnitSize ) and priTargetRegionHeight[ i ] shall be less than or equal to ( pri_target_pic_height_minus1 + 1 ).

14. The method of claim 13, wherein the pri_target_region_top_left_x[ i ] and the pri_target_region_top_left_y[ i ] indicate horizontal and vertical positions, respectively, of a top left sample position, in units of priUnitSize luma samples, of an i-th region in a reconstructed target picture, wherein the priTargetRegionWidth and the priTargetRegionHeight represent a width and a height, respectively, in luma samples of a resampled region in the reconstructed target picture, and wherein the pri target pic width minus 1 plus 1 and the pri_target_pic_height_minus1 plus 1 indicate a width and a height, respectively, in luma samples, of a target picture that may be reconstructed from samples of a cropped decoded picture corresponding to regions described in the PRI SEI message.

15. The method of claim 12, wherein, when pri_target_pic_params_present_flag is equal to 1, a sum of pri_target_region_top_left_xf i ] and priTargetRegionWidth[ i ] shall be less than or equal to ( pri target pic width minusl + 1 ) and the sum of pri target region top left y[ i ] and priTargetRegionHeight[ i ] shall be less than or equal to ( pri_target_pic_height_minus1 + 1 ).

16. The method of claim 15, wherein the pri_target_region_top_left_x[ i ] and the pri_target_region_top_left_y[ i ] indicate horizontal and vertical positions, respectively, of a top left sample position, in units of priUnitSize luma samples, of an i-th region in a reconstructed target picture, wherein the priTargetRegionWidth and the priTargetRegionHeight represent a width and a height, respectively, in lumasamples of a resampled region in the reconstructed target picture, and wherein priUnitSize represents a PRI unit size.

17. The method of any of claims 1-16, wherein one or more constraints are not included in the PRI SEI message when no target picture is specified.

18. The method of claim 17, wherein when pri_target_pic_params_present_flag is equal to 0, pri_num_resampling_ratios_minusl is not included in the bitstream.

19. The method of claim 17, wherein when pri target pic params present flag is equal to 0, pri_resampling_width_num_minusl is not included in the bitstream.

20. The method of claim 17, wherein when pri target pic params present flag is equal to 0, pri_resampling_width_denom_minusl is not included in the bitstream.

21. The method of claim 17, wherein when pri target pic params present Hag is equal to 0, pri_fixed_aspect_ratio_flag is not included in the bitstream.

22. The method of claim 17, wherein when pri_target_pic_params_present_flag is equal to 0, pri resampling height num minusl is not included in the bitstream.

23. The method of claim 17, wherein when pri_target_pic_params_present_flag is equal to 0, pri resampling height denom minusl is not included in the bitstream.

24. The method of claim 17, wherein when pri_target_pic_params_present_flag is equal to 0, pri_resampling_ratio_idx is not included in the bitstream.

25. The method of any of claims 1-24, wherein when a first PRI SEI message (priSeiA) and a second PRI SEI message (priSeiB) are present in different access units (AUs) in a coded video sequence (CVS), the priSeiA precedes the priSeiB in output order, and apri persistence flag of priSeiA is equal to 0, there is no third PRI SEI message (priSeiC) with pri_cancel_flag equal to 1 between the priSeiA and the priSeiB in output order.

26. The method of any of claims 1-24, wherein when a first PRI SEI message (priSeiA) and a second PRI SEI message (priSeiB) are present in different access units (AUs) in a coded video sequence (CVS), the priSeiA precedes the priSeiB in output order, and a pri_persistence_flag of priSeiA is equal to 1, there is no third PRI SEI message (priSeiC) with pri_cancel_flag equal to 1 between the priSeiA and the priSeiB in output order.

27. The method of any of claims 1-24, wherein when a first PRI SEI message (priSeiA) and a second PRI SEI message (priSeiB) are present in different access units (AUs) in a coded video sequence (CVS), the priSeiB follows the priSeiA in output order, a pri_persistence_flag of priSeiA is equal to 1, and a ListOfAssociatedLayers of the priSeiA and a ListOfAssociatedLayers of the priSeiB are not identical but there is m and n such that a value of the ListOfAssociatedLayers [m] of the priSeiA is equal to a value of the ListOfAssociatedLayers[n] of the priSeiB, there shall be a third PRI SEI message (priSeiC) that satisfies the following conditions:a value of a pri_cancel_flag of priSeiC is equal to 1;the priSeiC is present in a prediction unit (PU) in a same layer as the PU that contains the seiPriA; the priSeiC follows the priSeiA in output order; andthe priSeiC precedes the priSeiB in output order.

28. The method of any of claims 1-27, wherein the conversion includes encoding the visual media data into the bitstream.

29. The method of any of claims 1-27, wherein the conversion includes decoding the visual media data from the bitstream.

30. An apparatus for processing video data comprising: a processor; and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to perform the method of any of claims 1-29.

31. A non-transitory computer readable medium comprising a computer program product for use by a video coding device, the computer program product comprising computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the video coding device to perform the method of any of claims 1-29.

32. A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises:determining to specify a horizontal position and a vertical position of a top left sample of an i-th region in a packed regions information (PRI) supplemental enhancement information (SEI) message; and performing a conversion between a visual media data and a bitstream based on the horizontal position and the vertical position of the top left sample of the i th region in the PRI SEI message.

33. A method for storing a bitstream of a video, comprising:determining to specify a horizontal position and a vertical position of a top left sample of an i-th region in a packed regions information (PRI) supplemental enhancement information (SEI) message;generating the bitstream based on the horizontal position and the vertical position of the top left sample of the i-th region in the PRI SEI message; andstoring the bitstream in a non- transitory computer-readable recording medium.

34. A method, apparatus, or system described in the present disclosure.

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