// Copyright 2018-2023 The Khronos Group Inc.
//
// SPDX-License-Identifier: CC-BY-4.0

[[decode-h265]]
== H.265 Decode Operations

Video decode operations using an <<decode-h265-profile,H.265 decode
profile>> can: be used to decode elementary video stream sequences compliant
to the <<itu-t-h265,ITU-T H.265 Specification>>.

[NOTE]
.Note
====
Refer to the <<preamble,Preamble>> for information on how the Khronos
Intellectual Property Rights Policy relates to normative references to
external materials not created by Khronos.
====

This process is performed according to the <<decode-operation-steps,video
decode operation steps>> with the codec-specific semantics defined in
section 8 of <<itu-t-h265,ITU-T H.265 Specification>>:

  * Syntax elements, derived values, and other parameters are applied from
    the following structures:
  ** The code:StdVideoH265VideoParameterSet structure corresponding to the
     <<decode-h265-active-vps,active VPS>> specifying the <<decode-h265-vps,
     H.265 video parameter set>>.
  ** The code:StdVideoH265SequenceParameterSet structure corresponding to
     the <<decode-h265-active-sps,active SPS>> specifying the
     <<decode-h265-sps, H.265 sequence parameter set>>.
  ** The code:StdVideoH265PictureParameterSet structure corresponding to the
     <<decode-h265-active-pps,active PPS>> specifying the <<decode-h265-pps,
     H.265 picture parameter set>>.
  ** The code:StdVideoDecodeH265PictureInfo structure specifying the
     <<decode-h265-picture-info,H.265 picture information>>.
  ** The code:StdVideoDecodeH265ReferenceInfo structures specifying the
     <<decode-h265-reference-info,H.265 reference information>>
     corresponding to the optional <<reconstructed-picture,reconstructed
     picture>> and any <<active-reference-pictures,active reference
     pictures>>.
  * The contents of the provided video bitstream buffer range are
    interpreted as defined in the <<decode-h265-bitstream-data-access,H.265
    Decode Bitstream Data Access>> section.
  * Picture data in the <<video-picture-resources,video picture resources>>
    corresponding to the used <<decode-h265-active-reference-picture-info,
    active reference pictures>>, <<decode-h265-output-picture-info,decode
    output picture>>, and optional <<decode-h265-reconstructed-picture-info,
    reconstructed picture>> is accessed as defined in the
    <<decode-h265-picture-data-access,H.265 Decode Picture Data Access>>
    section.

If the parameters and the bitstream adhere to the syntactic and semantic
requirements defined in the corresponding sections of the <<itu-t-h265,ITU-T
H.265 Specification>>, as described above, and the <<dpb-slot,DPB slots>>
associated with the <<active-reference-pictures,active reference pictures>>
all refer to <<dpb-slot-states,valid picture references>>, then the video
decode operation will complete successfully.
Otherwise, the video decode operation may: complete
<<decode-unsuccessful,unsuccessfully>>.


[[decode-h265-bitstream-data-access]]
=== H.265 Decode Bitstream Data Access

The video bitstream buffer range should: contain a VCL NAL unit comprised of
the slice segment headers and data of a picture representing a frame, as
defined in sections 7.3.6 and 7.3.8, and this data is interpreted as defined
in sections 7.4.7 and 7.4.9 of the <<itu-t-h265, ITU-T H.265
Specification>>, respectively.

The offsets provided in
slink:VkVideoDecodeH265PictureInfoKHR::pname:pSliceSegmentOffsets should:
specify the starting offsets corresponding to each slice segment header
within the video bitstream buffer range.


[[decode-h265-picture-data-access]]
=== H.265 Decode Picture Data Access

Accesses to image data within a video picture resource happen at the
granularity indicated by
slink:VkVideoCapabilitiesKHR::pname:pictureAccessGranularity, as returned by
flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the used <<video-profiles,
video profile>>.
Accordingly, the complete image subregion of a
<<decode-output-picture,decode output picture>>,
<<reference-picture,reference picture>>, or
<<reconstructed-picture,reconstructed picture>> accessed by video coding
operations using an <<decode-h265-profile,H.265 decode profile>> is defined
as the set of texels within the coordinate range:

  {empty}:: [eq]#([0,pname:endX),[0,pname:endY))#

Where:

  * [eq]#pname:endX# equals [eq]#pname:codedExtent.width# rounded up to the
    nearest integer multiple of pname:pictureAccessGranularity.width and
    clamped to the width of the image subresource
    <<video-image-subresource-reference,referred>> to by the corresponding
    slink:VkVideoPictureResourceInfoKHR structure;
  * [eq]#endY# equals [eq]#pname:codedExtent.height# rounded up to the
    nearest integer multiple of pname:pictureAccessGranularity.height and
    clamped to the height of the image subresource
    <<video-image-subresource-reference, referred>> to by the corresponding
    slink:VkVideoPictureResourceInfoKHR structure;

Where pname:codedExtent is the member of the
slink:VkVideoPictureResourceInfoKHR structure corresponding to the picture.

In case of video decode operations using an <<decode-h265-profile,H.265
decode profile>>, any access to a picture at the coordinates
[eq]#(pname:x,pname:y)#, as defined by the <<itu-t-h265,ITU-T H.265
Specification>>, is an access to the image subresource
<<video-image-subresource-reference,referred>> to by the corresponding
slink:VkVideoPictureResourceInfoKHR structure at the texel coordinates
[eq]#(pname:x,pname:y)#.


[[decode-h265-profile]]
=== H.265 Decode Profile

[open,refpage='VkVideoDecodeH265ProfileInfoKHR',desc='Structure specifying H.265 decode profile',type='structs']
--
A video profile supporting H.265 video decode operations is specified by
setting slink:VkVideoProfileInfoKHR::pname:videoCodecOperation to
ename:VK_VIDEO_CODEC_OPERATION_DECODE_H265_BIT_KHR and adding a
sname:VkVideoDecodeH265ProfileInfoKHR structure to the
slink:VkVideoProfileInfoKHR::pname:pNext chain.

The sname:VkVideoDecodeH265ProfileInfoKHR structure is defined as:

include::{generated}/api/structs/VkVideoDecodeH265ProfileInfoKHR.adoc[]

  * pname:sType is a elink:VkStructureType value identifying this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:stdProfileIdc is a code:StdVideoH265ProfileIdc value specifying
    the H.265 codec profile IDC, as defined in section A3 of the
    <<itu-t-h265,ITU-T H.265 Specification>>.

include::{generated}/validity/structs/VkVideoDecodeH265ProfileInfoKHR.adoc[]
--


=== H.265 Decode Capabilities

[open,refpage='VkVideoDecodeH265CapabilitiesKHR',desc='Structure describing H.265 decode capabilities',type='structs']
--
When calling flink:vkGetPhysicalDeviceVideoCapabilitiesKHR to query the
capabilities for an <<decode-h265-profile,H.265 decode profile>>, the
slink:VkVideoCapabilitiesKHR::pname:pNext chain must: include a
sname:VkVideoDecodeH265CapabilitiesKHR structure that will be filled with
the profile-specific capabilities.

The sname:VkVideoDecodeH265CapabilitiesKHR structure is defined as:

include::{generated}/api/structs/VkVideoDecodeH265CapabilitiesKHR.adoc[]

  * pname:sType is a elink:VkStructureType value identifying this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:maxLevelIdc is a code:StdVideoH265LevelIdc value specifying the
    maximum H.265 level supported by the profile, where enum constant
    `STD_VIDEO_H265_LEVEL_IDC_<major>_<minor>` identifies H.265 level
    `<major>.<minor>` as defined in section A.4 of the <<itu-t-h265,ITU-T
    H.265 Specification>>.

include::{generated}/validity/structs/VkVideoDecodeH265CapabilitiesKHR.adoc[]
--


[[decode-h265-parameter-sets]]
=== H.265 Decode Parameter Sets

<<video-session-parameters,Video session parameters>> objects created with
the video codec operation ename:VK_VIDEO_CODEC_OPERATION_DECODE_H265_BIT_KHR
can: contain the following types of parameters:

[[decode-h265-vps]]
H.265 Video Parameter Sets (VPS)::

Represented by code:StdVideoH265VideoParameterSet structures and interpreted
as follows:

  * code:reserved1, code:reserved2, and code:reserved3 are used only for
    padding purposes and are otherwise ignored;
  * code:vps_video_parameter_set_id is used as the key of the VPS entry;
  * the code:max_latency_increase_plus1, code:max_dec_pic_buffering_minus1,
    and code:max_num_reorder_pics members of the
    code:StdVideoH265DecPicBufMgr structure pointed to by code:pDecPicBufMgr
    correspond to `vps_max_latency_increase_plus1`,
    `vps_max_dec_pic_buffering_minus1`, and `vps_max_num_reorder_pics`,
    respectively, as defined in section 7.4.3.1 of the <<itu-t-h265,ITU-T
    H.265 Specification>>;
  * the code:StdVideoH265HrdParameters structure pointed to by
    code:pHrdParameters is interpreted as follows:
  ** code:reserved is used only for padding purposes and is otherwise
     ignored;
  ** code:flags.fixed_pic_rate_general_flag is a bitmask where bit index
     [eq]#i# corresponds to `fixed_pic_rate_general_flag[i]` as defined in
     section E.3.2 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  ** code:flags.fixed_pic_rate_within_cvs_flag is a bitmask where bit index
     [eq]#i# corresponds to `fixed_pic_rate_within_cvs_flag[i]` as defined
     in section E.3.2 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  ** code:flags.low_delay_hrd_flag is a bitmask where bit index [eq]#i#
     corresponds to `low_delay_hrd_flag[i]` as defined in section E.3.2 of
     the <<itu-t-h265,ITU-T H.265 Specification>>;
  ** if code:flags.nal_hrd_parameters_present_flag is set, then
     code:pSubLayerHrdParametersNal is a pointer to an array of
     [eq]#code:vps_max_sub_layers_minus1 + 1# number of
     code:StdVideoH265SubLayerHrdParameters structures where
     code:vps_max_sub_layers_minus1 is the corresponding member of the
     encompassing code:StdVideoH265VideoParameterSet structure and each
     element is interpreted as follows:
  *** code:cbr_flag is a bitmask where bit index [eq]#i# corresponds to
      `cbr_flag[i]` as defined in section E.3.3 of the <<itu-t-h265,ITU-T
      H.265 Specification>>;
  *** all other members of the code:StdVideoH265SubLayerHrdParameters
      structure are interpreted as defined in section E.3.3 of the
      <<itu-t-h265,ITU-T H.265 Specification>>;
  ** if code:flags.vcl_hrd_parameters_present_flag is set, then
     code:pSubLayerHrdParametersVcl is a pointer to an array of
     [eq]#code:vps_max_sub_layers_minus1 + 1# number of
     code:StdVideoH265SubLayerHrdParameters structures where
     code:vps_max_sub_layers_minus1 is the corresponding member of the
     encompassing code:StdVideoH265VideoParameterSet structure and each
     element is interpreted as follows:
  *** code:cbr_flag is a bitmask where bit index [eq]#i# corresponds to
      `cbr_flag[i]` as defined in section E.3.3 of the <<itu-t-h265,ITU-T
      H.265 Specification>>;
  *** all other members of the code:StdVideoH265SubLayerHrdParameters
      structure are interpreted as defined in section E.3.3 of the
      <<itu-t-h265,ITU-T H.265 Specification>>;
  ** all other members of code:StdVideoH265HrdParameters are interpreted as
     defined in section E.3.2 of the <<itu-t-h265,ITU-T H.265
     Specification>>;
  * the code:StdVideoH265ProfileTierLevel structure pointed to by
    code:pProfileTierLevel are interpreted as follows:
  ** code:general_level_idc is one of the enum constants
     `STD_VIDEO_H265_LEVEL_IDC_<major>_<minor>` identifying the H.265 level
     `<major>.<minor>` as defined in section A.4 of the <<itu-t-h265,ITU-T
     H.265 Specification>>;
  ** all other members of code:StdVideoH265ProfileTierLevel are interpreted
     as defined in section 7.4.4 of the <<itu-t-h265,ITU-T H.265
     Specification>>;
  * all other members of code:StdVideoH265VideoParameterSet are interpreted
    as defined in section 7.4.3.1 of the <<itu-t-h265,ITU-T H.265
    Specification>>.

[[decode-h265-sps]]
H.265 Sequence Parameter Sets (SPS)::

Represented by code:StdVideoH265SequenceParameterSet structures and
interpreted as follows:

  * code:reserved1 and code:reserved2 are used only for padding purposes and
    are otherwise ignored;
  * the pair constructed from code:sps_video_parameter_set_id and
    code:sps_seq_parameter_set_id is used as the key of the SPS entry;
  * the code:StdVideoH265ProfileTierLevel structure pointed to by
    code:pProfileTierLevel are interpreted as follows:
  ** code:general_level_idc is one of the enum constants
     `STD_VIDEO_H265_LEVEL_IDC_<major>_<minor>` identifying the H.265 level
     `<major>.<minor>` as defined in section A.4 of the <<itu-t-h265,ITU-T
     H.265 Specification>>;
  ** all other members of code:StdVideoH265ProfileTierLevel are interpreted
     as defined in section 7.4.4 of the <<itu-t-h265,ITU-T H.265
     Specification>>;
  * the code:max_latency_increase_plus1, code:max_dec_pic_buffering_minus1,
    and code:max_num_reorder_pics members of the
    code:StdVideoH265DecPicBufMgr structure pointed to by code:pDecPicBufMgr
    correspond to `sps_max_latency_increase_plus1`,
    `sps_max_dec_pic_buffering_minus1`, and `sps_max_num_reorder_pics`,
    respectively, as defined in section 7.4.3.2 of the <<itu-t-h265,ITU-T
    H.265 Specification>>;
  * if code:flags.sps_scaling_list_data_present_flag is set, then the
    code:StdVideoH265ScalingLists structure pointed to by code:pScalingLists
    is interpreted as follows:
  ** code:ScalingList4x4, code:ScalingList8x8, code:ScalingList16x16, and
     code:ScalingList32x32 correspond to `ScalingList[0]`, `ScalingList[1]`,
     `ScalingList[2]`, and `ScalingList[3]`, respectively, as defined in
     section 7.3.4 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  ** code:ScalingListDCCoef16x16 and code:ScalingListDCCoef32x32 correspond
     to `scaling_list_dc_coef_minus8[0]` and
     `scaling_list_dc_coef_minus8[1]`, respectively, as defined in section
     7.3.4 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  * code:pShortTermRefPicSet is a pointer to an array of
    code:num_short_term_ref_pic_sets number of
    code:StdVideoH265ShortTermRefPicSet structures where each element is
    interpreted as follows:
  ** code:reserved1, code:reserved2, and code:reserved3 are used only for
     padding purposes and are otherwise ignored;
  ** code:used_by_curr_pic_flag is a bitmask where bit index [eq]#i#
     corresponds to `used_by_curr_pic_flag[i]` as defined in section 7.4.8
     of the <<itu-t-h265,ITU-T H.265 Specification>>;
  ** code:use_delta_flag is a bitmask where bit index [eq]#i# corresponds to
     `use_delta_flag[i]` as defined in section 7.4.8 of the <<itu-t-h265,
     ITU-T H.265 Specification>>;
  ** code:used_by_curr_pic_s0_flag is a bitmask where bit index [eq]#i#
     corresponds to `used_by_curr_pic_s0_flag[i]` as defined in section
     7.4.8 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  ** code:used_by_curr_pic_s1_flag is a bitmask where bit index [eq]#i#
     corresponds to `used_by_curr_pic_s1_flag[i]` as defined in section
     7.4.8 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  ** all other members of code:StdVideoH265ShortTermRefPicSet are
     interpreted as defined in section 7.4.8 of the <<itu-t-h265,ITU-T H.265
     Specification>>;
  * if code:flags.long_term_ref_pics_present_flag is set then the
    code:StdVideoH265LongTermRefPicsSps structure pointed to by
    code:pLongTermRefPicsSps is interpreted as follows:
  ** code:used_by_curr_pic_lt_sps_flag is a bitmask where bit index [eq]#i#
     corresponds to `used_by_curr_pic_lt_sps_flag[i]` as defined in section
     7.4.3.2 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  ** all other members of code:StdVideoH265LongTermRefPicsSps are
     interpreted as defined in section 7.4.3.2 of the <<itu-t-h265,ITU-T
     H.265 Specification>>;
  * if code:flags.vui_parameters_present_flag is set, then the
    code:StdVideoH265SequenceParameterSetVui structure pointed to by
    code:pSequenceParameterSetVui is interpreted as follows:
  ** code:reserved1, code:reserved2, and code:reserved3 are used only for
     padding purposes and are otherwise ignored;
  ** the code:StdVideoH265HrdParameters structure pointed to by
     code:pHrdParameters is interpreted as follows:
  *** code:flags.fixed_pic_rate_general_flag is a bitmask where bit index
      [eq]#i# corresponds to `fixed_pic_rate_general_flag[i]` as defined in
      section E.3.2 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  *** code:flags.fixed_pic_rate_within_cvs_flag is a bitmask where bit index
      [eq]#i# corresponds to `fixed_pic_rate_within_cvs_flag[i]` as defined
      in section E.3.2 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  *** code:flags.low_delay_hrd_flag is a bitmask where bit index [eq]#i#
      corresponds to `low_delay_hrd_flag[i]` as defined in section E.3.2 of
      the <<itu-t-h265,ITU-T H.265 Specification>>;
  *** if code:flags.nal_hrd_parameters_present_flag is set, then
      code:pSubLayerHrdParametersNal is a pointer to an array of
      [eq]#code:sps_max_sub_layers_minus1 + 1# number of
      code:StdVideoH265SubLayerHrdParameters structures where
      code:sps_max_sub_layers_minus1 is the corresponding member of the
      encompassing code:StdVideoH265SequenceParameterSet structure and each
      element is interpreted as follows:
  **** code:cbr_flag is a bitmask where bit index [eq]#i# corresponds to
       `cbr_flag[i]` as defined in section E.3.3 of the <<itu-t-h265,ITU-T
       H.265 Specification>>;
  **** all other members of the code:StdVideoH265SubLayerHrdParameters
       structure are interpreted as defined in section E.3.3 of the
       <<itu-t-h265,ITU-T H.265 Specification>>;
  *** if code:flags.vcl_hrd_parameters_present_flag is set, then
      code:pSubLayerHrdParametersVcl is a pointer to an array of
      [eq]#code:sps_max_sub_layers_minus1 + 1# number of
      code:StdVideoH265SubLayerHrdParameters structures where
      code:sps_max_sub_layers_minus1 is the corresponding member of the
      encompassing code:StdVideoH265SequenceParameterSet structure and each
      element is interpreted as follows:
  **** code:cbr_flag is a bitmask where bit index [eq]#i# corresponds to
       `cbr_flag[i]` as defined in section E.3.3 of the <<itu-t-h265,ITU-T
       H.265 Specification>>;
  **** all other members of the code:StdVideoH265SubLayerHrdParameters
       structure are interpreted as defined in section E.3.3 of the
       <<itu-t-h265,ITU-T H.265 Specification>>;
  *** all other members of code:StdVideoH265HrdParameters are interpreted as
      defined in section E.3.2 of the <<itu-t-h265,ITU-T H.265
      Specification>>;
  ** all other members of code:pSequenceParameterSetVui are interpreted as
     defined in section E.3.1 of the <<itu-t-h265,ITU-T H.265
     Specification>>;
  * if code:flags.sps_palette_predictor_initializer_present_flag is set,
    then the code:PredictorPaletteEntries member of the
    code:StdVideoH265PredictorPaletteEntries structure pointed to by
    code:pPredictorPaletteEntries is interpreted as defined in section
    7.4.9.13 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  * all other members of code:StdVideoH265SequenceParameterSet are
    interpreted as defined in section 7.4.3.1 of the <<itu-t-h265,ITU-T
    H.265 Specification>>.

[[decode-h265-pps]]
H.265 Picture Parameter Sets (PPS)::

Represented by code:StdVideoH265PictureParameterSet structures and
interpreted as follows:

  * code:reserved1, code:reserved2, and code:reserved3 are used only for
    padding purposes and are otherwise ignored;
  * the triplet constructed from code:sps_video_parameter_set_id,
    code:pps_seq_parameter_set_id, and code:pps_pic_parameter_set_id is used
    as the key of the PPS entry;
  * if code:flags.pps_scaling_list_data_present_flag is set, then the
    code:StdVideoH265ScalingLists structure pointed to by code:pScalingLists
    is interpreted as follows:
  ** code:ScalingList4x4, code:ScalingList8x8, code:ScalingList16x16, and
     code:ScalingList32x32 correspond to `ScalingList[0]`, `ScalingList[1]`,
     `ScalingList[2]`, and `ScalingList[3]`, respectively, as defined in
     section 7.3.4 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  ** code:ScalingListDCCoef16x16 and code:ScalingListDCCoef32x32 correspond
     to `scaling_list_dc_coef_minus8[0]` and
     `scaling_list_dc_coef_minus8[1]`, respectively, as defined in section
     7.3.4 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  * if code:flags.pps_palette_predictor_initializer_present_flag is set,
    then the code:PredictorPaletteEntries member of the
    code:StdVideoH265PredictorPaletteEntries structure pointed to by
    code:pPredictorPaletteEntries is interpreted as defined in section
    7.4.9.13 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  * all other members of code:StdVideoH265PictureParameterSet are
    interpreted as defined in section 7.4.3.3 of the <<itu-t-h265,ITU-T
    H.265 Specification>>.

[open,refpage='VkVideoDecodeH265SessionParametersCreateInfoKHR',desc='Structure specifies H.265 decoder parameter set information',type='structs']
--
When a <<video-session-parameters,video session parameters>> object is
created with the codec operation
ename:VK_VIDEO_CODEC_OPERATION_DECODE_H265_BIT_KHR, the
slink:VkVideoSessionParametersCreateInfoKHR::pname:pNext chain must: include
a sname:VkVideoDecodeH265SessionParametersCreateInfoKHR structure specifying
the capacity and initial contents of the object.

The sname:VkVideoDecodeH265SessionParametersCreateInfoKHR structure is
defined as:

include::{generated}/api/structs/VkVideoDecodeH265SessionParametersCreateInfoKHR.adoc[]

  * pname:sType is a elink:VkStructureType value identifying this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:maxStdVPSCount is the maximum number of <<decode-h265-vps,H.265
    VPS>> entries the created sname:VkVideoSessionParametersKHR can:
    contain.
  * pname:maxStdSPSCount is the maximum number of <<decode-h265-sps,H.265
    SPS>> entries the created sname:VkVideoSessionParametersKHR can:
    contain.
  * pname:maxStdPPSCount is the maximum number of <<decode-h265-pps,H.265
    PPS>> entries the created sname:VkVideoSessionParametersKHR can:
    contain.
  * pname:pParametersAddInfo is `NULL` or a pointer to a
    slink:VkVideoDecodeH265SessionParametersAddInfoKHR structure specifying
    H.265 parameters to add upon object creation.

include::{generated}/validity/structs/VkVideoDecodeH265SessionParametersCreateInfoKHR.adoc[]
--

[open,refpage='VkVideoDecodeH265SessionParametersAddInfoKHR',desc='Structure specifies H.265 decoder parameter set information',type='structs']
--
The sname:VkVideoDecodeH265SessionParametersAddInfoKHR structure is defined
as:

include::{generated}/api/structs/VkVideoDecodeH265SessionParametersAddInfoKHR.adoc[]

  * pname:sType is a elink:VkStructureType value identifying this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:stdVPSCount is the number of elements in the pname:pStdVPSs array.
  * pname:pStdVPSs is a pointer to an array of
    code:StdVideoH265VideoParameterSet structures describing the
    <<decode-h265-vps,H.265 VPS>> entries to add.
  * pname:stdSPSCount is the number of elements in the pname:pStdSPSs array.
  * pname:pStdSPSs is a pointer to an array of
    code:StdVideoH265SequenceParameterSet structures describing the
    <<decode-h265-sps,H.265 SPS>> entries to add.
  * pname:stdPPSCount is the number of elements in the pname:pStdPPSs array.
  * pname:pStdPPSs is a pointer to an array of
    code:StdVideoH265PictureParameterSet structures describing the
    <<decode-h265-pps,H.265 PPS>> entries to add.

This structure can: be specified in the following places:

  * In the pname:pParametersAddInfo member of the
    slink:VkVideoDecodeH265SessionParametersCreateInfoKHR structure
    specified in the pname:pNext chain of
    slink:VkVideoSessionParametersCreateInfoKHR used to create a
    <<video-session-parameters,video session parameters>> object.
    In this case, if the video codec operation the video session parameters
    object is created with is
    ename:VK_VIDEO_CODEC_OPERATION_DECODE_H265_BIT_KHR, then it defines the
    set of initial parameters to add to the created object (see
    <<creating-video-session-parameters,Creating Video Session
    Parameters>>).
  * In the pname:pNext chain of slink:VkVideoSessionParametersUpdateInfoKHR.
    In this case, if the video codec operation the
    <<video-session-parameters,video session parameters>> object to be
    updated was created with is
    ename:VK_VIDEO_CODEC_OPERATION_DECODE_H265_BIT_KHR, then it defines the
    set of parameters to add to it (see
    <<video-session-parameters-update,Updating Video Session Parameters>>).

.Valid Usage
****
  * [[VUID-VkVideoDecodeH265SessionParametersAddInfoKHR-None-04833]]
    The pname:vps_video_parameter_set_id member of each
    code:StdVideoH265VideoParameterSet structure specified in the elements
    of pname:pStdVPSs must: be unique within pname:pStdVPSs
  * [[VUID-VkVideoDecodeH265SessionParametersAddInfoKHR-None-04834]]
    The pair constructed from the pname:sps_video_parameter_set_id and
    pname:sps_seq_parameter_set_id members of each
    code:StdVideoH265SequenceParameterSet structure specified in the
    elements of pname:pStdSPSs must: be unique within pname:pStdSPSs
  * [[VUID-VkVideoDecodeH265SessionParametersAddInfoKHR-None-04835]]
    The triplet constructed from the pname:sps_video_parameter_set_id,
    pname:pps_seq_parameter_set_id, and pname:pps_pic_parameter_set_id
    members of each code:StdVideoH265PictureParameterSet structure specified
    in the elements of pname:pStdPPSs must: be unique within pname:pStdPPSs
****

include::{generated}/validity/structs/VkVideoDecodeH265SessionParametersAddInfoKHR.adoc[]
--


=== H.265 Decoding Parameters

[open,refpage='VkVideoDecodeH265PictureInfoKHR',desc='Structure specifies H.265 picture information when decoding a frame',type='structs']
--
The sname:VkVideoDecodeH265PictureInfoKHR structure is defined as:

include::{generated}/api/structs/VkVideoDecodeH265PictureInfoKHR.adoc[]

  * pname:sType is a elink:VkStructureType value identifying this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:pStdPictureInfo is a pointer to a
    code:StdVideoDecodeH265PictureInfo structure specifying
    <<decode-h265-picture-info,H.265 picture information>>.
  * pname:sliceSegmentCount is the number of elements in
    pname:pSliceSegmentOffsets.
  * pname:pSliceSegmentOffsets is a pointer to an array of
    pname:sliceSegmentCount offsets specifying the start offset of the slice
    segments of the picture within the video bitstream buffer range
    specified in slink:VkVideoDecodeInfoKHR.

This structure is specified in the pname:pNext chain of the
slink:VkVideoDecodeInfoKHR structure passed to flink:vkCmdDecodeVideoKHR to
specify the codec-specific picture information for an <<decode-h265,H.265
decode operation>>.

[[decode-h265-output-picture-info]]
Decode Output Picture Information::

When this structure is specified in the pname:pNext chain of the
slink:VkVideoDecodeInfoKHR structure passed to flink:vkCmdDecodeVideoKHR,
the information related to the <<decode-output-picture-info,decode output
picture>> is defined as follows:

  * The image subregion used is determined according to the
    <<decode-h265-picture-data-access,H.265 Decode Picture Data Access>>
    section.
  * The decode output picture is associated with the
    <<decode-h265-picture-info,H.265 picture information>> provided in
    pname:pStdPictureInfo.

[[decode-h265-picture-info]]
Std Picture Information::

The members of the code:StdVideoDecodeH265PictureInfo structure pointed to
by pname:pStdPictureInfo are interpreted as follows:

  * code:reserved is used only for padding purposes and is otherwise
    ignored;
  * code:flags.IrapPicFlag as defined in section 3.73 of the <<itu-t-h265,
    ITU-T H.265 Specification>>;
  * code:flags.IdrPicFlag as defined in section 3.67 of the
    <<itu-t-h265,ITU-T H.265 Specification>>;
  * code:flags.IsReference as defined in section 3.132 of the <<itu-t-h265,
    ITU-T H.265 Specification>>;
  * code:sps_video_parameter_set_id, code:pps_seq_parameter_set_id, and
    code:pps_pic_parameter_set_id are used to identify the active parameter
    sets, as described below;
  * code:PicOrderCntVal as defined in section 8.3.1 of the
    <<itu-t-h265,ITU-T H.265 Specification>>;
  * code:NumBitsForSTRefPicSetInSlice is the number of bits used in
    `st_ref_pic_set` when `short_term_ref_pic_set_sps_flag` is `0`, or `0`
    otherwise, as defined in sections 7.4.7 and 7.4.8 of the <<itu-t-h265,
    ITU-T H.265 Specification>>;
  * code:NumDeltaPocsOfRefRpsIdx is the value of `NumDeltaPocs[RefRpsIdx]`
    when `short_term_ref_pic_set_sps_flag` is `1`, or `0` otherwise, as
    defined in sections 7.4.7 and 7.4.8 of the <<itu-t-h265,ITU-T H.265
    Specification>>;
  * code:RefPicSetStCurrBefore, code:RefPicSetStCurrAfter, and
    code:RefPicSetLtCurr are interpreted as defined in section 8.3.2 of the
    <<itu-t-h265,ITU-T H.265 Specification>> where each element of these
    arrays either identifies an
    <<decode-active-reference-picture-info,active reference picture>> using
    its <<dpb-slot,DPB slot>> index or contains the value 0xFF to indicate
    "no reference picture";
  * all other members are interpreted as defined in section 8.3.2 of the
    <<itu-t-h265,ITU-T H.265 Specification>>.

Active Parameter Sets::

The members of the code:StdVideoDecodeH265PictureInfo structure pointed to
by pname:pStdPictureInfo are used to select the active parameter sets to use
from the bound video session parameters object, as follows:

  * [[decode-h265-active-vps]] The _active VPS_ is the
    <<decode-h265-vps,VPS>> identified by the key specified in
    code:StdVideoDecodeH265PictureInfo::code:sps_video_parameter_set_id.
  * [[decode-h265-active-sps]] The _active SPS_ is the
    <<decode-h265-sps,SPS>> identified by the key specified by the pair
    constructed from
    code:StdVideoDecodeH265PictureInfo::code:sps_video_parameter_set_id and
    code:StdVideoDecodeH265PictureInfo::code:pps_seq_parameter_set_id.
  * [[decode-h265-active-pps]] The _active PPS_ is the
    <<decode-h265-pps,PPS>> identified by the key specified by the triplet
    constructed from
    code:StdVideoDecodeH265PictureInfo::code:sps_video_parameter_set_id,
    code:StdVideoDecodeH265PictureInfo::code:pps_seq_parameter_set_id, and
    code:StdVideoDecodeH265PictureInfo::code:pps_pic_parameter_set_id.

include::{generated}/validity/structs/VkVideoDecodeH265PictureInfoKHR.adoc[]
--

[open,refpage='VkVideoDecodeH265DpbSlotInfoKHR',desc='Structure specifies H.265 DPB information when decoding a frame',type='structs']
--
The sname:VkVideoDecodeH265DpbSlotInfoKHR structure is defined as:

include::{generated}/api/structs/VkVideoDecodeH265DpbSlotInfoKHR.adoc[]

  * pname:sType is a elink:VkStructureType value identifying this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:pStdReferenceInfo is a pointer to a
    code:StdVideoDecodeH265ReferenceInfo structure specifying reference
    picture information described in section 8.3 of the <<itu-t-h265,ITU-T
    H.265 Specification>>.

This structure is specified in the pname:pNext chain of
slink:VkVideoDecodeInfoKHR::pname:pSetupReferenceSlot, if not `NULL`, and
the pname:pNext chain of the elements of
slink:VkVideoDecodeInfoKHR::pname:pReferenceSlots to specify the
codec-specific reference picture information for an <<decode-h265,H.265
decode operation>>.

[[decode-h265-active-reference-picture-info]]
Active Reference Picture Information::

When this structure is specified in the pname:pNext chain of the elements of
slink:VkVideoDecodeInfoKHR::pname:pReferenceSlots, one element is added to
the list of <<decode-active-reference-picture-info,active reference
pictures>> used by the video decode operation for each element of
slink:VkVideoDecodeInfoKHR::pname:pReferenceSlots as follows:

  * The image subregion used is determined according to the
    <<decode-h265-picture-data-access,H.265 Decode Picture Data Access>>
    section.
  * The reference picture is associated with the <<dpb-slot,DPB slot>> index
    specified in the pname:slotIndex member of the corresponding element of
    slink:VkVideoDecodeInfoKHR::pname:pReferenceSlots.
  * The reference picture is associated with the
    <<decode-h265-reference-info,H.265 reference information>> provided in
    pname:pStdReferenceInfo.

[[decode-h265-reconstructed-picture-info]]
Reconstructed Picture Information::

When this structure is specified in the pname:pNext chain of
slink:VkVideoDecodeInfoKHR::pname:pSetupReferenceSlot, the information
related to the <<decode-reconstructed-picture-info,reconstructed picture>>
is defined as follows:

  * The image subregion used is determined according to the
    <<decode-h265-picture-data-access,H.265 Decode Picture Data Access>>
    section.
  * The reconstructed picture is used to <<dpb-slot-states,activate>> the
    <<dpb-slot,DPB slot>> with the index specified in
    slink:VkVideoDecodeInfoKHR::pname:pSetupReferenceSlot->slotIndex.
  * The reconstructed picture is associated with the
    <<decode-h265-reference-info,H.265 reference information>> provided in
    pname:pStdReferenceInfo.

[[decode-h265-reference-info]]
Std Reference Information::

The members of the code:StdVideoDecodeH265ReferenceInfo structure pointed to
by pname:pStdReferenceInfo are interpreted as follows:

  * code:flags.used_for_long_term_reference is used to indicate whether the
    picture is marked as "`used for long-term reference`" as defined in
    section 8.3.2 of the <<itu-t-h265,ITU-T H.265 Specification>>;
  * code:flags.unused_for_reference is used to indicate whether the picture
    is marked as "`unused for reference`" as defined in section 8.3.2 of the
    <<itu-t-h265,ITU-T H.265 Specification>>;
  * all other members are interpreted as defined in section 8.3 of the
    <<itu-t-h265,ITU-T H.265 Specification>>.

include::{generated}/validity/structs/VkVideoDecodeH265DpbSlotInfoKHR.adoc[]
--


[[decode-h265-requirements]]
=== H.265 Decode Requirements

This section describes the required: H.265 decoding capabilities for
physical devices that have at least one queue family that supports the video
codec operation ename:VK_VIDEO_CODEC_OPERATION_DECODE_H265_BIT_KHR, as
returned by flink:vkGetPhysicalDeviceQueueFamilyProperties2 in
slink:VkQueueFamilyVideoPropertiesKHR::pname:videoCodecOperations.

.Required <<video-std-header-version,Video Std Header Versions>>
[options="header"]
|====
| Video Std Header Name | Version
| `vulkan_video_codec_h265std_decode` | 1.0.0
|====