path: root/chapters/video/encode.adoc

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

[[video-encode-operations]]
== Video Encode Operations

[[encode-input-picture]]
Video encode operations consume an _encode input picture_ and zero or more
reference pictures, and produce compressed video data to a video bitstream
buffer and an optional <<reconstructed-picture,reconstructed picture>>.

[NOTE]
.Note
====
Such encode input pictures can be used
ifdef::VK_KHR_video_decode_queue[]
as the <<decode-output-picture,output>> of video decode operations,
endif::VK_KHR_video_decode_queue[]
with graphics or compute operations,
ifdef::VK_KHR_surface[]
or with <<wsi,Window System Integration>> APIs,
endif::VK_KHR_surface[]
depending on the capabilities of the implementation.
====

Video encode operations may: access the following resources in the
ename:VK_PIPELINE_STAGE_2_VIDEO_ENCODE_BIT_KHR stage:

  * The image subregions corresponding to the source
    <<encode-input-picture-info,encode input picture>> and
    <<encode-active-reference-picture-info,active reference pictures>> with
    access ename:VK_ACCESS_2_VIDEO_ENCODE_READ_BIT_KHR.
  * The destination video bitstream buffer range and the optional
    <<encode-reconstructed-picture-info,reconstructed picture>> with access
    ename:VK_ACCESS_2_VIDEO_ENCODE_WRITE_BIT_KHR.

The image subresource of each <<video-picture-resources,video picture
resource>> accessed by the video encode operation is specified using a
corresponding slink:VkVideoPictureResourceInfoKHR structure.
Each such image subresource must: be in the appropriate image layout as
follows:

  * If the image subresource is used in the video encode operation as an
    <<encode-input-picture,encode input picture>>, then it must: be in the
    ename:VK_IMAGE_LAYOUT_VIDEO_ENCODE_SRC_KHR layout.
  * If the image subresource is used in the video encode operation as a
    <<reconstructed-picture,reconstructed picture>> or <<reference-picture,
    reference picture>>, then it must: be in the
    ename:VK_IMAGE_LAYOUT_VIDEO_ENCODE_DPB_KHR layout.

[[encode-unsuccessful]]
A video encode operation may: complete unsuccessfully.
In this case the target video bitstream buffer will have undefined:
contents.
Similarly, if <<encode-ref-pic-setup,reference picture setup>> is requested,
the <<reconstructed-picture,reconstructed-picture>> will also have
undefined: contents, and the activated DPB slot will have an
<<dpb-slot-states,invalid picture reference>>.

If a video encode operation completes successfully and the codec-specific
parameters provided by the application adhere to the syntactic and semantic
requirements defined in the corresponding video compression standard, then
the target video bitstream buffer will contain compressed video data after
the execution of the video encode operation according to the respective
<<encode-codec-specific-semantics,codec-specific semantics>>.


[[encode-codec-specific-semantics]]
=== Codec-Specific Semantics

The following aspects of video encode operations are codec-specific:

  * The compressed video data written to the target video bitstream buffer
    range.
  * The construction and interpretation of the list of
    <<encode-active-reference-picture-info,active reference pictures>> and
    the interpretation of the picture data referred to by the corresponding
    image subregions.
  * The construction and interpretation of information related to the
    <<encode-input-picture-info,encode input picture>> and the
    interpretation of the picture data referred to by the corresponding
    image subregion.
  * The decision on <<encode-ref-pic-setup,reference picture setup>>.
  * The construction and interpretation of information related to the
    optional <<encode-reconstructed-picture-info,reconstructed picture>> and
    the generation of picture data to the corresponding image subregion.
  * Certain aspects of <<encode-rate-control,rate control>>.

These codec-specific behaviors are defined for each video codec operation
separately.

ifdef::VK_KHR_video_encode_h264[]
  * If the used video codec operation is
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, then the
    codec-specific aspects of the video encoding process are performed as
    defined in the <<encode-h264,H.264 Encode Operations>> section.
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  * If the used video codec operation is
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then the
    codec-specific aspects of the video encoding process are performed as
    defined in the <<encode-h265,H.265 Encode Operations>> section.
endif::VK_KHR_video_encode_h265[]


[[encode-overrides]]
==== Video Encode Parameter Overrides

Implementations supporting video encode operations for any particular video
codec operation often support only a subset of the available encoding tools
defined by the corresponding video compression standards.
Accordingly, certain implementation-dependent limitations may: apply to
codec-specific parameters provided through the structures defined in the
Video Std headers corresponding to the used video codec operation.

Exposing all of these restrictions on particular codec-specific parameter
values or combinations thereof in the form of application-queryable
capabilities is impractical, hence this specification allows implementations
to _override_ the value of any of the codec-specific parameters, unless
otherwise specified, as long as all of the following conditions are met:

  * If the application-provided codec-specific parameters adhere to the
    syntactic and semantic requirements and rules defined by the used video
    compression standard, and thus would be usable to produce a video
    bitstream compliant with that standard, then the codec-specific
    parameters resulting from the process of implementation overrides must:
    also adhere to the same requirements and rules, and any video bitstream
    produced using the overridden parameters must: also be compliant.
  * The overridden codec-specific parameter values must: not have an impact
    on the codec-independent behaviors defined for video encode operations.
  * The implementation must: not override any codec-specific parameters
    specified to a command that may: cause application-provided
    codec-specific parameters specified to subsequent commands to no longer
    adhere to the semantic requirements and rules defined by the used video
    compression standard, unless the implementation also overrides those
    parameters to adhere to any such requirements and rules.
  * The overridden codec-specific parameter values must: not have an impact
    on the codec-specific picture data access semantics.
  * The overridden codec-specific parameter values may: change the contents
    of the codec-specific bitstream elements produced by video encode
    operations or otherwise retrieved by the application (e.g. using the
    flink:vkGetEncodedVideoSessionParametersKHR command) but must: still
    adhere to the codec-specific semantics defined for that video codec
    operation, including, but not limited to, the number, type, and order of
    the encoded codec-specific bitstream elements.

Besides codec-specific parameter overrides performed for
implementation-dependent reasons, applications can: enable the
implementation to apply additional <<encode-optimizing-overrides,optimizing
overrides>> that may: improve the efficiency or performance of video
encoding operations.
However, implementations must: meet the conditions listed above even in case
of such optimizing overrides.

[NOTE]
.Note
====
Unless the application opts in for optimizing overrides, implementations are
not expected to override any of the codec-specific parameters, except when
such overrides are necessary for the correct operation of video encoder
implementation due to limitations to the available encoding tools on that
implementation.
====


[[encode-operation-steps]]
=== Video Encode Operation Steps

Each video encode operation performs the following steps in the
ename:VK_PIPELINE_STAGE_2_VIDEO_ENCODE_BIT_KHR stage:

  1. Reads the input picture data from the <<encode-input-picture,encode
     input picture>>;
  2. Determine derived encoding quality parameters according to the
     <<encode-codec-specific-semantics,codec-specific semantics>> and the
     current <<encode-rate-control,rate control>> state;
  3. Compresses the input picture data according to the
     <<encode-codec-specific-semantics,codec-specific semantics>>, applying
     any prediction data read from the <<active-reference-pictures,active
     reference pictures>> and rate control restrictions in the process;
  4. Writes the encoded bitstream data to the destination video bitstream
     buffer range;
  5. Performs picture reconstruction of the encoded video data according to
     the <<encode-codec-specific-semantics,codec-specific semantics>>,
     applying any prediction data read from the <<active-reference-pictures,
     active reference pictures>> in the process, if a
     <<reconstructed-picture,reconstructed picture>> is specified and
     <<encode-ref-pic-setup,reference picture setup>> is requested;
  6. If <<encode-ref-pic-setup,reference picture setup>> is requested, the
     <<dpb-slot,DPB slot index>> specified in the
     <<encode-reconstructed-picture-info,reconstructed picture information>>
     is <<dpb-slot-states,activated>> with the
     <<reconstructed-picture,reconstructed picture>>;
  7. Writes the reconstructed picture data to the <<reconstructed-picture,
     reconstructed picture>>, if one is specified, according to the
     <<encode-codec-specific-semantics,codec-specific semantics>>.

When <<encode-reconstructed-picture-info,reconstructed picture information>>
is provided, the specified <<dpb-slot,DPB slot>> index is associated with
the corresponding <<bound-reference-picture-resources,bound reference
picture resource>>, indifferent of whether <<encode-ref-pic-setup,reference
picture setup>> is requested.

=== Capabilities

[open,refpage='VkVideoEncodeCapabilitiesKHR',desc='Structure describing general video encode capabilities for a video profile',type='structs']
--
When calling flink:vkGetPhysicalDeviceVideoCapabilitiesKHR with
pname:pVideoProfile->videoCodecOperation specifying an encode operation, the
slink:VkVideoEncodeCapabilitiesKHR structure must: be included in the
pname:pNext chain of the slink:VkVideoCapabilitiesKHR structure to retrieve
capabilities specific to video encoding.

The sname:VkVideoEncodeCapabilitiesKHR structure is defined as:

include::{generated}/api/structs/VkVideoEncodeCapabilitiesKHR.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:flags is a bitmask of elink:VkVideoEncodeCapabilityFlagBitsKHR
    describing supported encoding features.
  * pname:rateControlModes is a bitmask of
    elink:VkVideoEncodeRateControlModeFlagBitsKHR indicating supported
    <<encode-rate-control-modes,rate control modes>>.
  * pname:maxRateControlLayers indicates the maximum number of
    <<encode-rate-control-layers,rate control layers>> supported.
  * pname:maxBitrate indicates the maximum supported bitrate.
  * pname:maxQualityLevels indicates the number of discrete
    <<encode-quality-level,video encode quality levels>> supported.
    Implementations must: support at least one quality level.
  * pname:encodeInputPictureGranularity indicates the granularity at which
    <<encode-input-picture,encode input picture>> data is encoded and may:
    indicate a texel granularity up to the size of the codec-specific coding
    block size.
    This capability does not impose any valid usage constraints on the
    application, however, depending on the contents of the encode input
    picture, it may: have effects on the encoded bitstream, as described in
    more detail below.
  * pname:supportedEncodeFeedbackFlags is a bitmask of
    elink:VkVideoEncodeFeedbackFlagBitsKHR values specifying the supported
    flags for <<queries-video-encode-feedback,video encode feedback
    queries>>.

Implementations must: include support for at least
ename:VK_VIDEO_ENCODE_FEEDBACK_BITSTREAM_BUFFER_OFFSET_BIT_KHR and
ename:VK_VIDEO_ENCODE_FEEDBACK_BITSTREAM_BYTES_WRITTEN_BIT_KHR in
pname:supportedEncodeFeedbackFlags.

pname:encodeInputPictureGranularity provides information about the way
<<encode-input-picture,encode input picture>> data is used as input to video
encode operations.
In particular, some implementations may: not be able to limit the set of
texels used to encode the output video bitstream to the image subregion
specified in the slink:VkVideoPictureResourceInfoKHR structure corresponding
to the encode input picture (i.e. to the resolution of the image data to
encode specified in its pname:codedExtent member).

[NOTE]
.Note
====
For example, the application requests the coded extent to be 1920x1080, but
the implementation is only able to source the encode input picture data at
the granularity of the codec-specific coding block size which is 16x16
pixels (or as otherwise indicated in pname:encodeInputPictureGranularity).
In this example, the content is horizontally aligned with the coding block
size, but not vertically aligned with it.
Thus encoding of the last row of coding blocks will be impacted by the
contents of the input image at texel rows 1080 to 1087 (the latter being the
next row which is vertically aligned with the coding block size, assuming a
zero-based texel row index).
====

If pname:codedExtent rounded up to the next integer multiple of
pname:encodeInputPictureGranularity is greater than the extent of the image
subresource specified for the <<encode-input-picture,encode input picture>>,
then the texel values corresponding to texel coordinates outside of the
bounds of the image subresource may: be undefined:.
However, implementations should: use well-defined default values for such
texels in order to maximize the encoding efficiency for the last coding
block row/column, and/or to ensure consistent encoding results across
repeated encoding of the same input content.
Nonetheless, the values used for such texels must: not have an effect on
whether the video encode operation produces a compliant bitstream, and must:
not have any other effects on the encoded picture data beyond what may:
otherwise result from using these texel values as input to any compression
algorithm, as defined in the used video compression standard.

[NOTE]
.Note
====
While not required, it is generally a good practice for applications to make
sure that the image subresource used for the encode input picture has an
extent that is an integer multiple of the codec-specific coding block size
(or at least pname:encodeInputPictureGranularity) and that this padding area
is filled with known values in order to improve encoding efficiency,
portability, and reproducibility.
====

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

[open,refpage='VkVideoEncodeCapabilityFlagBitsKHR',desc='Video encode capability flags',type='enums']
--
Bits which may: be set in slink:VkVideoEncodeCapabilitiesKHR::pname:flags,
indicating the encoding tools supported, are:

include::{generated}/api/enums/VkVideoEncodeCapabilityFlagBitsKHR.adoc[]

  * ename:VK_VIDEO_ENCODE_CAPABILITY_PRECEDING_EXTERNALLY_ENCODED_BYTES_BIT_KHR
    indicates that the implementation supports the use of
    slink:VkVideoEncodeInfoKHR::pname:precedingExternallyEncodedBytes.
  * ename:VK_VIDEO_ENCODE_CAPABILITY_INSUFFICIENT_BITSTREAM_BUFFER_RANGE_DETECTION_BIT_KHR
    indicates that the implementation is able to detect and report when the
    destination video bitstream buffer range provided by the application is
    not sufficiently large to fit the encoded bitstream data produced by a
    video encode operation by reporting the
    ename:VK_QUERY_RESULT_STATUS_INSUFFICIENT_BITSTREAM_BUFFER_RANGE_KHR
    <<query-result-status-codes,query result status code>>.
+
[NOTE]
.Note
====
Some implementations may: not be able to reliably detect insufficient
bitstream buffer range conditions in all situations.
Such implementations will not report support for the
ename:VK_VIDEO_ENCODE_CAPABILITY_INSUFFICIENT_BITSTREAM_BUFFER_RANGE_DETECTION_BIT_KHR
encode capability flag for the video profile, but may: still report the
ename:VK_QUERY_RESULT_STATUS_INSUFFICIENT_BITSTREAM_BUFFER_RANGE_KHR query
result status code in certain cases.
Applications should: always check for the specific query result status code
ename:VK_QUERY_RESULT_STATUS_INSUFFICIENT_BITSTREAM_BUFFER_RANGE_KHR even
when this encode capability flag is not supported by the implementation for
the video profile in question.
However, applications must: not assume that a different negative query
result status code indicating an unsuccessful completion of a video encode
operation is not the result of an insufficient bitstream buffer condition
unless this encode capability flag is supported.
====
--

[open,refpage='VkVideoEncodeCapabilityFlagsKHR',desc='Bitmask of VkVideoEncodeCapabilityFlagBitsKHR',type='flags']
--
include::{generated}/api/flags/VkVideoEncodeCapabilityFlagsKHR.adoc[]

tname:VkVideoEncodeCapabilityFlagsKHR is a bitmask type for setting a mask
of zero or more elink:VkVideoEncodeCapabilityFlagBitsKHR.
--


[[encode-quality-level]]
=== Video Encode Quality Levels

Implementations can: support more than one video encode quality levels for a
video encode profile, which control the number and type of
implementation-specific encoding tools and algorithms utilized in the
encoding process.

[NOTE]
.Note
====
Generally, using higher video encode quality levels may: produce higher
quality video streams at the cost of additional processing time.
However, as the final quality of an encoded picture depends on the contents
of the <<encode-input-picture,encode input picture>>, the contents of the
<<active-reference-pictures,active reference pictures>>, the codec-specific
encode parameters, and the particular implementation-specific tools used
corresponding to the individual video encode quality levels, there are no
guarantees that using a higher video encode quality level will always
produce a higher quality encoded picture for any given set of inputs.
====

[open,refpage='vkGetPhysicalDeviceVideoEncodeQualityLevelPropertiesKHR',desc='Query video encode quality level properties',type='protos']
--
To query properties for a specific video encode quality level supported by a
video encode profile, call:

include::{generated}/api/protos/vkGetPhysicalDeviceVideoEncodeQualityLevelPropertiesKHR.adoc[]

  * pname:physicalDevice is the physical device to query the video encode
    quality level properties for.
  * pname:pQualityLevelInfo is a pointer to a
    slink:VkPhysicalDeviceVideoEncodeQualityLevelInfoKHR structure
    specifying the video encode profile and quality level to query
    properties for.
  * pname:pQualityLevelProperties is a pointer to a
    slink:VkVideoEncodeQualityLevelPropertiesKHR structure in which the
    properties are returned.

.Valid Usage
****
ifdef::VK_KHR_video_encode_h264[]
  * [[VUID-vkGetPhysicalDeviceVideoEncodeQualityLevelPropertiesKHR-pQualityLevelInfo-08257]]
    If pname:pQualityLevelInfo->pVideoProfile->videoCodecOperation is
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, then the pname:pNext
    chain of pname:pQualityLevelProperties must: include a
    slink:VkVideoEncodeH264QualityLevelPropertiesKHR structure
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  * [[VUID-vkGetPhysicalDeviceVideoEncodeQualityLevelPropertiesKHR-pQualityLevelInfo-08258]]
    If pname:pQualityLevelInfo->pVideoProfile->videoCodecOperation is
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then the pname:pNext
    chain of pname:pQualityLevelProperties must: include a
    slink:VkVideoEncodeH265QualityLevelPropertiesKHR structure
endif::VK_KHR_video_encode_h265[]
****

include::{generated}/validity/protos/vkGetPhysicalDeviceVideoEncodeQualityLevelPropertiesKHR.adoc[]
--


[open,refpage='VkPhysicalDeviceVideoEncodeQualityLevelInfoKHR',desc='Structure describing the video encode profile and quality level to query properties for',type='structs']
--
The sname:VkPhysicalDeviceVideoEncodeQualityLevelInfoKHR structure is
defined as:

include::{generated}/api/structs/VkPhysicalDeviceVideoEncodeQualityLevelInfoKHR.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:pVideoProfile is a pointer to a slink:VkVideoProfileInfoKHR
    structure specifying the video profile to query the video encode quality
    level properties for.
  * pname:qualityLevel is the video encode quality level to query properties
    for.

.Valid Usage
****
  * [[VUID-VkPhysicalDeviceVideoEncodeQualityLevelInfoKHR-pVideoProfile-08259]]
    pname:pVideoProfile must: be a <<video-profile-support, supported video
    profile>>
  * [[VUID-VkPhysicalDeviceVideoEncodeQualityLevelInfoKHR-pVideoProfile-08260]]
    pname:pVideoProfile->videoCodecOperation must: specify an encode
    operation
  * [[VUID-VkPhysicalDeviceVideoEncodeQualityLevelInfoKHR-qualityLevel-08261]]
    pname:qualityLevel must: be less than
    slink:VkVideoEncodeCapabilitiesKHR::pname:maxQualityLevels, as returned
    by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video profile
    specified in pname:pVideoProfile
****

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


[open,refpage='VkVideoEncodeQualityLevelPropertiesKHR',desc='Structure describing the video encode quality level properties',type='structs']
--
The sname:VkVideoEncodeQualityLevelPropertiesKHR structure is defined as:

include::{generated}/api/structs/VkVideoEncodeQualityLevelPropertiesKHR.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:preferredRateControlMode is a
    elink:VkVideoEncodeRateControlModeFlagBitsKHR value indicating the
    preferred <<encode-rate-control-modes,rate control mode>> to use with
    the video encode quality level.
  * pname:preferredRateControlLayerCount indicates the preferred number of
    <<encode-rate-control-layers,rate control layers>> to use with the video
    encode quality level.

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


[open,refpage='VkVideoEncodeQualityLevelInfoKHR',desc='Structure specifying used video encode quality level',type='structs']
--
The sname:VkVideoEncodeQualityLevelInfoKHR structure is defined as:

include::{generated}/api/structs/VkVideoEncodeQualityLevelInfoKHR.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:qualityLevel is the used video encode quality level.

This structure can: be specified in the following places:

  * In the pname:pNext chain of slink:VkVideoSessionParametersCreateInfoKHR
    to specify the video encode quality level to use for a video session
    parameters object created for a video encode session.
    If no instance of this structure is included in the pname:pNext chain of
    slink:VkVideoSessionParametersCreateInfoKHR, then the video session
    parameters object is created with a video encode quality level of zero.
  * In the pname:pNext chain of slink:VkVideoCodingControlInfoKHR to change
    the video encode quality level state of the bound video session.

.Valid Usage
****
  * [[VUID-VkVideoEncodeQualityLevelInfoKHR-qualityLevel-08311]]
    pname:qualityLevel must: be less than
    slink:VkVideoEncodeCapabilitiesKHR::pname:maxQualityLevels, as returned
    by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the used video
    profile
****

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


=== Retrieving Encoded Session Parameters

Any codec-specific parameters stored in video session parameters objects
may: need to be separately encoded and included in the final video bitstream
data, depending on the used video compression standard.
In such cases the application must: call the
flink:vkGetEncodedVideoSessionParametersKHR command to retrieve the encoded
parameter data from the used video session parameters object in order to be
able to produce a compliant video bitstream.

[NOTE]
.Note
====
This is needed because implementations may: have changed some of the
codec-specific parameters stored in the video session parameters object, as
defined in the <<encode-overrides,Video Encode Parameter Overrides>>
section.
In addition, the flink:vkGetEncodedVideoSessionParametersKHR command enables
the application to retrieve the encoded parameter data without having to
encode these codec-specific parameters manually.
====

[open,refpage='vkGetEncodedVideoSessionParametersKHR',desc='Get encoded parameter sets from a video session parameters object',type='protos']
--
Encoded parameter data can: be retrieved from a video session parameters
object created with a video encode operation using the command:

include::{generated}/api/protos/vkGetEncodedVideoSessionParametersKHR.adoc[]

  * pname:device is the logical device that owns the video session
    parameters object.
  * pname:pVideoSessionParametersInfo is a pointer to a
    slink:VkVideoEncodeSessionParametersGetInfoKHR structure specifying the
    parameters of the encoded parameter data to retrieve.
  * pname:pFeedbackInfo is either `NULL` or a pointer to a
    slink:VkVideoEncodeSessionParametersFeedbackInfoKHR structure in which
    feedback about the requested parameter data is returned.
  * pname:pDataSize is a pointer to a code:size_t value related to the
    amount of encode parameter data returned, as described below.
  * pname:pData is either `NULL` or a pointer to a buffer to write the
    encoded parameter data to.

If pname:pData is `NULL`, then the size of the encoded parameter data, in
bytes, that can: be retrieved is returned in pname:pDataSize.
Otherwise, pname:pDataSize must: point to a variable set by the application
to the size of the buffer, in bytes, pointed to by pname:pData, and on
return the variable is overwritten with the number of bytes actually written
to pname:pData.
If pname:pDataSize is less than the size of the encoded parameter data that
can: be retrieved, then no data will be written to pname:pData, zero will be
written to pname:pDataSize, and ename:VK_INCOMPLETE will be returned instead
of ename:VK_SUCCESS, to indicate that no encoded parameter data was
returned.

If pname:pFeedbackInfo is not `NULL` then the members of the
slink:VkVideoEncodeSessionParametersFeedbackInfoKHR structure and any
additional structures included in its pname:pNext chain that are applicable
to the video session parameters object specified in
pname:pVideoSessionParametersInfo::pname:videoSessionParameters will be
filled with feedback about the requested parameter data on all successful
calls to this command.

[NOTE]
.Note
====
This includes the cases when pname:pData is `NULL` or when
ename:VK_INCOMPLETE is returned by the command, and enables the application
to determine whether the implementation <<encode-overrides,overrode>> any of
the requested video session parameters without actually needing to retrieve
the encoded parameter data itself.
====

.Valid Usage
****
  * [[VUID-vkGetEncodedVideoSessionParametersKHR-pVideoSessionParametersInfo-08359]]
    pname:pVideoSessionParametersInfo->videoSessionParameters must: have
    been created with an encode operation
ifdef::VK_KHR_video_encode_h264[]
  * [[VUID-vkGetEncodedVideoSessionParametersKHR-pVideoSessionParametersInfo-08262]]
    If pname:pVideoSessionParametersInfo->videoSessionParameters was created
    with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, then the pname:pNext
    chain of pname:pVideoSessionParametersInfo must: include a
    slink:VkVideoEncodeH264SessionParametersGetInfoKHR structure
  * [[VUID-vkGetEncodedVideoSessionParametersKHR-pVideoSessionParametersInfo-08263]]
    If pname:pVideoSessionParametersInfo->videoSessionParameters was created
    with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, then for the
    slink:VkVideoEncodeH264SessionParametersGetInfoKHR structure included in
    the pname:pNext chain of pname:pVideoSessionParametersInfo, if its
    pname:writeStdSPS member is ename:VK_TRUE, then
    pname:pVideoSessionParametersInfo->videoSessionParameters must: contain
    a code:StdVideoH264SequenceParameterSet entry with
    pname:seq_parameter_set_id matching
    slink:VkVideoEncodeH264SessionParametersGetInfoKHR::pname:stdSPSId
  * [[VUID-vkGetEncodedVideoSessionParametersKHR-pVideoSessionParametersInfo-08264]]
    If pname:pVideoSessionParametersInfo->videoSessionParameters was created
    with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, then for the
    slink:VkVideoEncodeH264SessionParametersGetInfoKHR structure included in
    the pname:pNext chain of pname:pVideoSessionParametersInfo, if its
    pname:writeStdPPS member is ename:VK_TRUE, then
    pname:pVideoSessionParametersInfo->videoSessionParameters must: contain
    a code:StdVideoH264PictureParameterSet entry with
    pname:seq_parameter_set_id and pname:pic_parameter_set_id matching
    slink:VkVideoEncodeH264SessionParametersGetInfoKHR::pname:stdSPSId and
    slink:VkVideoEncodeH264SessionParametersGetInfoKHR::pname:stdPPSId,
    respectively
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  * [[VUID-vkGetEncodedVideoSessionParametersKHR-pVideoSessionParametersInfo-08265]]
    If pname:pVideoSessionParametersInfo->videoSessionParameters was created
    with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then the pname:pNext
    chain of pname:pVideoSessionParametersInfo must: include a
    slink:VkVideoEncodeH265SessionParametersGetInfoKHR structure
  * [[VUID-vkGetEncodedVideoSessionParametersKHR-pVideoSessionParametersInfo-08266]]
    If pname:pVideoSessionParametersInfo->videoSessionParameters was created
    with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then for the
    slink:VkVideoEncodeH265SessionParametersGetInfoKHR structure included in
    the pname:pNext chain of pname:pVideoSessionParametersInfo, if its
    pname:writeStdVPS member is ename:VK_TRUE, then
    pname:pVideoSessionParametersInfo->videoSessionParameters must: contain
    a code:StdVideoH265VideoParameterSet entry with
    pname:vps_video_parameter_set_id matching
    slink:VkVideoEncodeH265SessionParametersGetInfoKHR::pname:stdVPSId
  * [[VUID-vkGetEncodedVideoSessionParametersKHR-pVideoSessionParametersInfo-08267]]
    If pname:pVideoSessionParametersInfo->videoSessionParameters was created
    with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then for the
    slink:VkVideoEncodeH265SessionParametersGetInfoKHR structure included in
    the pname:pNext chain of pname:pVideoSessionParametersInfo, if its
    pname:writeStdSPS member is ename:VK_TRUE, then
    pname:pVideoSessionParametersInfo->videoSessionParameters must: contain
    a code:StdVideoH265SequenceParameterSet entry with
    pname:sps_video_parameter_set_id and pname:sps_seq_parameter_set_id
    matching
    slink:VkVideoEncodeH265SessionParametersGetInfoKHR::pname:stdVPSId and
    slink:VkVideoEncodeH265SessionParametersGetInfoKHR::pname:stdSPSId,
    respectively
  * [[VUID-vkGetEncodedVideoSessionParametersKHR-pVideoSessionParametersInfo-08268]]
    If pname:pVideoSessionParametersInfo->videoSessionParameters was created
    with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then for the
    slink:VkVideoEncodeH265SessionParametersGetInfoKHR structure included in
    the pname:pNext chain of pname:pVideoSessionParametersInfo, if its
    pname:writeStdPPS member is ename:VK_TRUE, then
    pname:pVideoSessionParametersInfo->videoSessionParameters must: contain
    a code:StdVideoH265PictureParameterSet entry with
    pname:sps_video_parameter_set_id, pname:pps_seq_parameter_set_id, and
    pname:pps_pic_parameter_set_id matching
    slink:VkVideoEncodeH265SessionParametersGetInfoKHR::pname:stdVPSId,
    slink:VkVideoEncodeH265SessionParametersGetInfoKHR::pname:stdSPSId, and
    slink:VkVideoEncodeH265SessionParametersGetInfoKHR::pname:stdPPSId,
    respectively
endif::VK_KHR_video_encode_h265[]
****

include::{generated}/validity/protos/vkGetEncodedVideoSessionParametersKHR.adoc[]
--

[open,refpage='VkVideoEncodeSessionParametersGetInfoKHR',desc='Structure specifying parameters for retrieving encoded video session parameter data',type='structs']
--
The sname:VkVideoEncodeSessionParametersGetInfoKHR structure is defined as:

include::{generated}/api/structs/VkVideoEncodeSessionParametersGetInfoKHR.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:videoSessionParameters is the slink:VkVideoSessionParametersKHR
    object to retrieve encoded parameter data from.

Depending on the used video encode operation, additional codec-specific
structures may: need to be included in the pname:pNext chain of this
structure to identify the specific video session parameters to retrieve
encoded parameter data for, as described in the corresponding sections.

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

[open,refpage='VkVideoEncodeSessionParametersFeedbackInfoKHR',desc='Structure providing feedback about the requested video session parameters',type='structs']
--
The sname:VkVideoEncodeSessionParametersFeedbackInfoKHR structure is defined
as:

include::{generated}/api/structs/VkVideoEncodeSessionParametersFeedbackInfoKHR.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:hasOverrides indicates whether any of the requested parameter data
    were <<encode-overrides,overridden>> by the implementation.

Depending on the used video encode operation, additional codec-specific
structures can: be be included in the pname:pNext chain of this structure to
capture codec-specific feedback information about the requested parameter
data, as described in the corresponding sections.

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


[[video-encode-commands]]
=== Video Encode Commands

[open,refpage='vkCmdEncodeVideoKHR',desc='Launch video encode operations',type='protos']
--
To launch video encode operations, call:

include::{generated}/api/protos/vkCmdEncodeVideoKHR.adoc[]

  * pname:commandBuffer is the command buffer in which to record the
    command.
  * pname:pEncodeInfo is a pointer to a slink:VkVideoEncodeInfoKHR structure
    specifying the parameters of the video encode operations.

Each call issues one or more video encode operations.
The implicit parameter pname:opCount corresponds to the number of video
encode operations issued by the command.
After calling this command, the
<<queries-operation-active-query-index,active query index>> of each
<<queries-operation-active,active>> query is incremented by pname:opCount.

Currently each call to this command results in the issue of a single video
encode operation.

ifdef::VK_KHR_video_maintenance1[]
If the bound video session was created with
ename:VK_VIDEO_SESSION_CREATE_INLINE_QUERIES_BIT_KHR and the pname:pNext
chain of pname:pEncodeInfo includes a slink:VkVideoInlineQueryInfoKHR
structure with its pname:queryPool member specifying a valid
sname:VkQueryPool handle, then this command will execute a query for each
video encode operation issued by it.
endif::VK_KHR_video_maintenance1[]

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

The list of <<active-reference-pictures,active reference pictures>> used by
a video encode operation is a list of image subregions used as the source of
<<reference-picture,reference picture>> data and related parameters, and is
derived from the slink:VkVideoReferenceSlotInfoKHR structures provided as
the elements of the pname:pEncodeInfo->pReferenceSlots array.
For each element of pname:pEncodeInfo->pReferenceSlots, one or more elements
are added to the active reference picture list, as defined by the
<<encode-codec-specific-semantics,codec-specific semantics>>.
Each element of this list contains the following information:

  * The image subregion within the image subresource
    <<video-image-subresource-reference,referred>> to by the
    <<video-picture-resources,video picture resource>> used as the reference
    picture.
  * The <<dpb-slot,DPB slot>> index the reference picture is associated
    with.
  * The codec-specific reference information related to the reference
    picture.

[[encode-reconstructed-picture-info]]
Reconstructed Picture Information::

Information related to the optional <<reconstructed-picture,reconstructed
picture>> used by a video encode operation is derived from the
slink:VkVideoReferenceSlotInfoKHR structure pointed to by
pname:pEncodeInfo->pSetupReferenceSlot, if not `NULL`, as defined by the
<<encode-codec-specific-semantics,codec-specific semantics>>, and consists
of the following:

  * The image subregion within the image subresource
    <<video-image-subresource-reference,referred>> to by the
    <<video-picture-resources,video picture resource>> used as the
    reconstructed picture.
  * The <<dpb-slot,DPB slot>> index to use for picture reconstruction.
  * The codec-specific reference information related to the reconstructed
    picture.

[[encode-ref-pic-setup]]
Specifying a valid slink:VkVideoReferenceSlotInfoKHR structure in
pname:pEncodeInfo->pSetupReferenceSlot is always required, unless the video
session was created with slink:VkVideoSessionCreateInfoKHR::pname:maxDpbSlot
equal to zero.
However, the DPB slot identified by
pname:pEncodeInfo->pSetupReferenceSlot->slotIndex is only
<<dpb-slot-states,activated>> with the <<reconstructed-picture,reconstructed
picture>> specified in
pname:pEncodeInfo->pSetupReferenceSlot->pPictureResource if reference
picture setup is requested according to the
<<encode-codec-specific-semantics,codec-specific semantics>>.

If reconstructed picture information is specified, but reference picture
setup is not requested, according to the codec-specific semantics, the
contents of the <<video-picture-resources,video picture resource>>
corresponding to the reconstructed picture will be undefined: after the
video encode operation.

[NOTE]
.Note
====
Some implementations may always output the reconstructed picture or use it
as temporary storage during the video encode operation even when the
reconstructed picture is not marked for future reference.
====

[[encode-input-picture-info]]
Encode Input Picture Information::

Information related to the <<encode-input-picture,encode input picture>>
used by a video encode operation is derived from
pname:pEncodeInfo->srcPictureResource and any codec-specific parameters
provided in the pname:pEncodeInfo->pNext chain, as defined by the
<<encode-codec-specific-semantics,codec-specific semantics>>, and consists
of the following:

  * The image subregion within the image subresource
    <<video-image-subresource-reference,referred>> to by the
    <<video-picture-resources,video picture resource>> used as the encode
    input picture.
  * The codec-specific picture information related to the encoded picture.

Several limiting values are defined below that are referenced by the
relevant valid usage statements of this command.

  * Let `uint32_t activeReferencePictureCount` be the size of the list of
    active reference pictures used by the video encode operation.
    Unless otherwise defined, pname:activeReferencePictureCount is set to
    the value of pname:pEncodeInfo->referenceSlotCount.
  * Let `VkOffset2D codedOffsetGranularity` be the minimum alignment
    requirement for the coded offset of video picture resources.
    Unless otherwise defined, the value of the pname:x and pname:y members
    of pname:codedOffsetGranularity are `0`.
  * Let `uint32_t dpbFrameUseCount[]` be an array of size pname:maxDpbSlots,
    where pname:maxDpbSlots is the
    slink:VkVideoSessionCreateInfoKHR::pname:maxDpbSlots the bound video
    session was created with, with each element indicating the number of
    times a frame associated with the corresponding DPB slot index is
    referred to by the video coding operation.
    Let the initial value of each element of the array be `0`.
  ** If pname:pEncodeInfo->pSetupReferenceSlot is not `NULL`, then
     `dpbFrameUseCount[i]` is incremented by one, where pname:i equals
     pname:pEncodeInfo->pSetupReferenceSlot->slotIndex.
  ** For each element of pname:pEncodeInfo->pReferenceSlots,
     `dpbFrameUseCount[i]` is incremented by one, where pname:i equals the
     pname:slotIndex member of the corresponding element.
  * Let `VkExtent2D maxCodingBlockSize` be the maximum codec-specific coding
    block size that may: be used by the video encode operation.
ifdef::VK_KHR_video_encode_h264[]
  ** If the bound video session object was created with an
     <<encode-h264-profile,H.264 encode profile>>, then let
     pname:maxCodingBlockSize be equal to the size of an H.264 macroblock,
     i.e. `{16,16}`.
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  ** If the bound video session object was created with an
     <<encode-h265-profile,H.265 encode profile>>, then let
     pname:maxCodingBlockSize be equal to the maximum H.265 coding block
     size that may: be used by the video encode operation derived as the
     maximum of the CTB sizes corresponding to the
     elink:VkVideoEncodeH265CtbSizeFlagBitsKHR bits set in
     slink:VkVideoEncodeH265CapabilitiesKHR::pname:ctbSizes, as returned by
     flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video profile the
     bound video session was created with.
endif::VK_KHR_video_encode_h265[]
  ** Otherwise, pname:maxCodingBlockSize is undefined:.
  * If pname:maxCodingBlockSize is defined, then let `VkExtent2D
    minCodingBlockExtent` be the coded extent of the
    <<encode-input-picture,encode input picture>> expressed in terms of
    codec-specific coding blocks, assuming the maximum size of such coding
    blocks, as defined by pname:maxCodingBlockSize, calculated from the
    value of the pname:codedExtent member of
    pname:pEncodeInfo->srcPictureResource as follows:
  ** [eq]#pname:minCodingBlockExtent.width = (pname:codedExtent.width +
     pname:maxCodingBlockSize.width - 1) / pname:maxCodingBlockSize.width#
  ** [eq]#pname:minCodingBlockExtent.height = (pname:codedExtent.height +
     pname:maxCodingBlockSize.height - 1) / pname:maxCodingBlockSize.height#
ifdef::VK_KHR_video_encode_h264[]
  * If the bound video session object was created with an
    <<encode-h264-profile,H.264 encode profile>>, then:
  ** Let `StdVideoH264PictureType h264PictureType` be the picture type of
     the encoded picture set to the value of
     pname:pStdPictureInfo->primary_pic_type specified in the
     slink:VkVideoEncodeH264PictureInfoKHR structure included in the
     pname:pEncodeInfo->pNext chain.
  ** Let `StdVideoH264PictureType h264L0PictureTypes[]` and
     `StdVideoH264PictureType h264L1PictureTypes[]` be the picture types of
     the reference pictures in the L0 and L1 reference lists, respectively.
     If pname:pStdPictureInfo->pRefLists specified in the
     slink:VkVideoEncodeH264PictureInfoKHR structure included in the
     pname:pEncodeInfo->pNext chain is not `NULL`, then for each reference
     index specified in the elements of the
     pname:pStdPictureInfo->pRefLists->RefPicList0 and
     pname:pStdPictureInfo->pRefLists->RefPicList1 arrays, if the reference
     index is not code:STD_VIDEO_H264_NO_REFERENCE_PICTURE,
     pname:pStdReferenceInfo->primary_pic_type is added to
     pname:h264L0PictureTypes or pname:h264L1PictureTypes, respectively,
     where pname:pStdReferenceInfo is the member of the
     slink:VkVideoEncodeH264DpbSlotInfoKHR structure included in the
     pname:pNext chain of the element of pname:pEncodeInfo->pReferenceSlots
     for which pname:slotIndex equals the reference index in question.
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  * If the bound video session object was created with an
    <<encode-h264-profile,H.265 encode profile>>, then:
  ** Let `StdVideoH265PictureType h265PictureType` be the picture type of
     the encoded picture set to the value of pname:pStdPictureInfo->pic_type
     specified in the slink:VkVideoEncodeH265PictureInfoKHR structure
     included in the pname:pEncodeInfo->pNext chain.
  ** Let `StdVideoH265PictureType h265L0PictureTypes[]` and
     `StdVideoH265PictureType h265L1PictureTypes[]` be the picture types of
     the reference pictures in the L0 and L1 reference lists, respectively.
     If pname:pStdPictureInfo->pRefLists specified in the
     slink:VkVideoEncodeH265PictureInfoKHR structure included in the
     pname:pEncodeInfo->pNext chain is not `NULL`, then for each reference
     index specified in the elements of the
     pname:pStdPictureInfo->pRefLists->RefPicList0 and
     pname:pStdPictureInfo->pRefLists->RefPicList1 arrays, if the reference
     index is not code:STD_VIDEO_H265_NO_REFERENCE_PICTURE,
     pname:pStdReferenceInfo->pic_type is added to pname:h265L0PictureTypes
     or pname:h265L1PictureTypes, respectively, where
     pname:pStdReferenceInfo is the member of the
     slink:VkVideoEncodeH265DpbSlotInfoKHR structure included in the
     pname:pNext chain of the element of pname:pEncodeInfo->pReferenceSlots
     for which pname:slotIndex equals the reference index in question.
endif::VK_KHR_video_encode_h265[]

.Valid Usage
****
  * [[VUID-vkCmdEncodeVideoKHR-None-08250]]
    The bound video session must: have been created with an encode operation
  * [[VUID-vkCmdEncodeVideoKHR-None-07012]]
    The bound video session must: not be in <<video-session-uninitialized,
    uninitialized>> state at the time the command is executed on the device
  * [[VUID-vkCmdEncodeVideoKHR-None-08318]]
    The bound video session parameters object must: have been created with
    the currently set <<encode-quality-level,video encode quality level>>
    for the bound video session at the time the command is executed on the
    device
  * [[VUID-vkCmdEncodeVideoKHR-opCount-07174]]
    For each <<queries-operation-active,active>> query, the
    <<queries-operation-active-query-index,active query index>>
    corresponding to the query type of that query plus pname:opCount must:
    be less than or equal to the
    <<queries-operation-last-activatable-query-index,last activatable query
    index>> corresponding to the query type of that query plus one
ifdef::VK_KHR_video_maintenance1[]
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08360]]
    If the bound video session was created with
    ename:VK_VIDEO_SESSION_CREATE_INLINE_QUERIES_BIT_KHR, and the
    pname:pNext chain of pname:pEncodeInfo includes a
    slink:VkVideoInlineQueryInfoKHR structure with its pname:queryPool
    member specifying a valid sname:VkQueryPool handle, then
    slink:VkVideoInlineQueryInfoKHR::queryCount must: equal ename:opCount
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08361]]
    If the bound video session was created with
    ename:VK_VIDEO_SESSION_CREATE_INLINE_QUERIES_BIT_KHR, and the
    pname:pNext chain of pname:pEncodeInfo includes a
    slink:VkVideoInlineQueryInfoKHR structure with its pname:queryPool
    member specifying a valid sname:VkQueryPool handle, then all the queries
    used by the command, as specified by the slink:VkVideoInlineQueryInfoKHR
    structure, must: be _unavailable_
  * [[VUID-vkCmdEncodeVideoKHR-queryType-08362]]
    If the bound video session was created with
    ename:VK_VIDEO_SESSION_CREATE_INLINE_QUERIES_BIT_KHR, then the
    pname:queryType used to create the pname:queryPool specified in the
    slink:VkVideoInlineQueryInfoKHR structure included in the pname:pNext
    chain of pname:pEncodeInfo must: be
    ename:VK_QUERY_TYPE_RESULT_STATUS_ONLY_KHR or
    ename:VK_QUERY_TYPE_VIDEO_ENCODE_FEEDBACK_KHR
  * [[VUID-vkCmdEncodeVideoKHR-queryPool-08363]]
    If the bound video session was created with
    ename:VK_VIDEO_SESSION_CREATE_INLINE_QUERIES_BIT_KHR, then the
    pname:queryPool specified in the slink:VkVideoInlineQueryInfoKHR
    structure included in the pname:pNext chain of pname:pEncodeInfo must:
    have been created with a slink:VkVideoProfileInfoKHR structure included
    in the pname:pNext chain of slink:VkQueryPoolCreateInfo identical to the
    one specified in slink:VkVideoSessionCreateInfoKHR::pname:pVideoProfile
    the bound video session was created with
  * [[VUID-vkCmdEncodeVideoKHR-queryType-08364]]
    If the bound video session was created with
    ename:VK_VIDEO_SESSION_CREATE_INLINE_QUERIES_BIT_KHR, and the
    pname:queryType used to create the pname:queryPool specified in the
    slink:VkVideoInlineQueryInfoKHR structure included in the pname:pNext
    chain of pname:pEncodeInfo is
    ename:VK_QUERY_TYPE_RESULT_STATUS_ONLY_KHR, then the sname:VkCommandPool
    that pname:commandBuffer was allocated from must: have been created with
    a queue family index that supports <<queries-result-status-only,result
    status queries>>, as indicated by
    slink:VkQueueFamilyQueryResultStatusPropertiesKHR::pname:queryResultStatusSupport
endif::VK_KHR_video_maintenance1[]
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08201]]
    pname:pEncodeInfo->dstBuffer must: be <<video-profile-compatibility,
    compatible>> with the video profile the bound video session was created
    with
  * [[VUID-vkCmdEncodeVideoKHR-commandBuffer-08202]]
    If pname:commandBuffer is an unprotected command buffer and
    <<limits-protectedNoFault, pname:protectedNoFault>> is not supported,
    then pname:pEncodeInfo->dstBuffer must: not be a protected buffer
  * [[VUID-vkCmdEncodeVideoKHR-commandBuffer-08203]]
    If pname:commandBuffer is a protected command buffer and
    <<limits-protectedNoFault, pname:protectedNoFault>> is not supported,
    then pname:pEncodeInfo->dstBuffer must: be a protected buffer
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08204]]
    pname:pEncodeInfo->dstBufferOffset must: be an integer multiple of
    slink:VkVideoCapabilitiesKHR::pname:minBitstreamBufferOffsetAlignment,
    as returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the
    video profile the bound video session was created with
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08205]]
    pname:pEncodeInfo->dstBufferRange must: be an integer multiple of
    slink:VkVideoCapabilitiesKHR::pname:minBitstreamBufferSizeAlignment, as
    returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video
    profile the bound video session was created with
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08206]]
    pname:pEncodeInfo->srcPictureResource.imageViewBinding must: be
    <<video-profile-compatibility,compatible>> with the video profile the
    bound video session was created with
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08207]]
    The format of pname:pEncodeInfo->srcPictureResource.imageViewBinding
    must: match the slink:VkVideoSessionCreateInfoKHR::pname:pictureFormat
    the bound video session was created with
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08208]]
    pname:pEncodeInfo->srcPictureResource.codedOffset must: be an integer
    multiple of pname:codedOffsetGranularity
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08209]]
    pname:pEncodeInfo->srcPictureResource.codedExtent must: be between
    pname:minCodedExtent and pname:maxCodedExtent, inclusive, the bound
    video session was created with
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08210]]
    pname:pEncodeInfo->srcPictureResource.imageViewBinding must: have been
    created with ename:VK_IMAGE_USAGE_VIDEO_ENCODE_SRC_BIT_KHR
  * [[VUID-vkCmdEncodeVideoKHR-commandBuffer-08211]]
    If pname:commandBuffer is an unprotected command buffer and
    <<limits-protectedNoFault, pname:protectedNoFault>> is not supported,
    then pname:pEncodeInfo->srcPictureResource.imageViewBinding must: not
    have been created from a protected image
  * [[VUID-vkCmdEncodeVideoKHR-commandBuffer-08212]]
    If pname:commandBuffer is a protected command buffer and
    <<limits-protectedNoFault, pname:protectedNoFault>> is not supported,
    then pname:pEncodeInfo->srcPictureResource.imageViewBinding must: have
    been created from a protected image
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08377]]
    pname:pEncodeInfo->pSetupReferenceSlot must: not be `NULL` unless the
    bound video session was created with
    slink:VkVideoSessionCreateInfoKHR::pname:maxDpbSlots equal to zero
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08213]]
    If pname:pEncodeInfo->pSetupReferenceSlot is not `NULL`, then
    pname:pEncodeInfo->pSetupReferenceSlot->slotIndex must: be less than the
    slink:VkVideoSessionCreateInfoKHR::pname:maxDpbSlots specified when the
    bound video session was created
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08214]]
    If pname:pEncodeInfo->pSetupReferenceSlot is not `NULL`, then
    pname:pEncodeInfo->pSetupReferenceSlot->pPictureResource->codedOffset
    must: be an integer multiple of pname:codedOffsetGranularity
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08215]]
    If pname:pEncodeInfo->pSetupReferenceSlot is not `NULL`, then
    pname:pEncodeInfo->pSetupReferenceSlot->pPictureResource must:
    <<video-picture-resource-matching,match>> one of the
    <<bound-reference-picture-resources,bound reference picture resource>>
  * [[VUID-vkCmdEncodeVideoKHR-activeReferencePictureCount-08216]]
    pname:activeReferencePictureCount must: be less than or equal to the
    slink:VkVideoSessionCreateInfoKHR::pname:maxActiveReferencePictures
    specified when the bound video session was created
  * [[VUID-vkCmdEncodeVideoKHR-slotIndex-08217]]
    The pname:slotIndex member of each element of
    pname:pEncodeInfo->pReferenceSlots must: be less than the
    slink:VkVideoSessionCreateInfoKHR::pname:maxDpbSlots specified when the
    bound video session was created
  * [[VUID-vkCmdEncodeVideoKHR-codedOffset-08218]]
    The pname:codedOffset member of the slink:VkVideoPictureResourceInfoKHR
    structure pointed to by the pname:pPictureResource member of each
    element of pname:pEncodeInfo->pReferenceSlots must: be an integer
    multiple of pname:codedOffsetGranularity
  * [[VUID-vkCmdEncodeVideoKHR-pPictureResource-08219]]
    The pname:pPictureResource member of each element of
    pname:pEncodeInfo->pReferenceSlots must:
    <<video-picture-resource-matching,match>> one of the
    <<bound-reference-picture-resources,bound reference picture resource>>
    associated with the DPB slot index specified in the pname:slotIndex
    member of that element
  * [[VUID-vkCmdEncodeVideoKHR-pPictureResource-08220]]
    Each video picture resource corresponding to the pname:pPictureResource
    member specified in the elements of pname:pEncodeInfo->pReferenceSlots
    must: be <<video-picture-resource-uniqueness,unique>> within
    pname:pEncodeInfo->pReferenceSlots
  * [[VUID-vkCmdEncodeVideoKHR-dpbFrameUseCount-08221]]
    All elements of pname:dpbFrameUseCount must: be less than or equal to
    `1`
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08222]]
    The image subresource <<video-image-subresource-reference,referred>> to
    by pname:pEncodeInfo->srcPictureResource must: be in the
    ename:VK_IMAGE_LAYOUT_VIDEO_ENCODE_SRC_KHR layout at the time the video
    encode operation is executed on the device
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08223]]
    If pname:pEncodeInfo->pSetupReferenceSlot is not `NULL`, then the image
    subresource <<video-image-subresource-reference,referred>> to by
    pname:pEncodeInfo->pSetupReferenceSlot->pPictureResource must: be in the
    ename:VK_IMAGE_LAYOUT_VIDEO_ENCODE_DPB_KHR layout at the time the video
    encode operation is executed on the device
  * [[VUID-vkCmdEncodeVideoKHR-pPictureResource-08224]]
    The image subresource <<video-image-subresource-reference,referred>> to
    by the pname:pPictureResource member of each element of
    pname:pEncodeInfo->pReferenceSlots must: be in the
    ename:VK_IMAGE_LAYOUT_VIDEO_ENCODE_DPB_KHR layout at the time the video
    encode operation is executed on the device
ifdef::VK_KHR_video_encode_h264[]
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08225]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, then the pname:pNext
    chain of pname:pEncodeInfo must: include a
    slink:VkVideoEncodeH264PictureInfoKHR structure
  * [[VUID-vkCmdEncodeVideoKHR-StdVideoH264SequenceParameterSet-08226]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, then the bound video
    session parameters object must: contain a
    code:StdVideoH264SequenceParameterSet entry with
    pname:seq_parameter_set_id matching
    code:StdVideoEncodeH264PictureInfo::pname:seq_parameter_set_id that is
    provided in the pname:pStdPictureInfo member of the
    slink:VkVideoEncodeH264PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo
  * [[VUID-vkCmdEncodeVideoKHR-StdVideoH264PictureParameterSet-08227]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, then the bound video
    session parameters object must: contain a
    code:StdVideoH264PictureParameterSet entry with
    pname:seq_parameter_set_id and pname:pic_parameter_set_id matching
    code:StdVideoEncodeH264PictureInfo::pname:seq_parameter_set_id and
    code:StdVideoEncodeH264PictureInfo::pname:pic_parameter_set_id,
    respectively, that are provided in the pname:pStdPictureInfo member of
    the slink:VkVideoEncodeH264PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08228]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR and
    pname:pEncodeInfo->pSetupReferenceSlot is not `NULL`, then the
    pname:pNext chain of pname:pEncodeInfo->pSetupReferenceSlot must:
    include a slink:VkVideoEncodeH264DpbSlotInfoKHR structure
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08229]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, then the pname:pNext
    chain of each element of pname:pEncodeInfo->pReferenceSlots must:
    include a slink:VkVideoEncodeH264DpbSlotInfoKHR structure
  * [[VUID-vkCmdEncodeVideoKHR-constantQp-08269]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR and the current
    <<encode-rate-control-modes,rate control mode>> is not
    ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DISABLED_BIT_KHR, then
    slink:VkVideoEncodeH264NaluSliceInfoKHR::pname:constantQp must: be zero
    for each element of the pname:pNaluSliceEntries member of the
    slink:VkVideoEncodeH264PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo
  * [[VUID-vkCmdEncodeVideoKHR-constantQp-08270]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR and the current
    <<encode-rate-control-modes,rate control mode>> is
    ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DISABLED_BIT_KHR, then
    slink:VkVideoEncodeH264NaluSliceInfoKHR::pname:constantQp must: be
    between slink:VkVideoEncodeH264CapabilitiesKHR::pname:minQp and
    slink:VkVideoEncodeH264CapabilitiesKHR::pname:maxQp, as returned by
    flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video profile the
    bound video session was created with, for each element of the
    pname:pNaluSliceEntries member of the
    slink:VkVideoEncodeH264PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo
  * [[VUID-vkCmdEncodeVideoKHR-constantQp-08271]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR and
    slink:VkVideoEncodeH264CapabilitiesKHR::pname:flags does not include
    ename:VK_VIDEO_ENCODE_H264_CAPABILITY_PER_SLICE_CONSTANT_QP_BIT_KHR, as
    returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video
    profile the bound video session was created with, then
    slink:VkVideoEncodeH264NaluSliceInfoKHR::pname:constantQp must: have the
    same value for each element of the pname:pNaluSliceEntries member of the
    slink:VkVideoEncodeH264PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo
  * [[VUID-vkCmdEncodeVideoKHR-naluSliceEntryCount-08302]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, then the
    pname:naluSliceEntryCount member of the
    slink:VkVideoEncodeH264PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo must: be less than or equal to
    pname:minCodingBlockExtent.width multiplied by
    pname:minCodingBlockExtent.height
  * [[VUID-vkCmdEncodeVideoKHR-naluSliceEntryCount-08312]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR and
    slink:VkVideoEncodeH264CapabilitiesKHR::pname:flags does not include
    ename:VK_VIDEO_ENCODE_H264_CAPABILITY_ROW_UNALIGNED_SLICE_BIT_KHR, as
    returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video
    profile the bound video session was created with, then the
    pname:naluSliceEntryCount member of the
    slink:VkVideoEncodeH264PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo must: be less than or equal to
    pname:minCodingBlockExtent.height
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08352]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, the pname:pNext
    chain of pname:pEncodeInfo includes a
    slink:VkVideoEncodeH264PictureInfoKHR structure, and
    pname:pEncodeInfo->referenceSlotCount is greater than zero, then
    slink:VkVideoEncodeH264PictureInfoKHR::pname:pStdPictureInfo->pRefLists
    must: not be `NULL`
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08339]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, the pname:pNext
    chain of pname:pEncodeInfo includes a
    slink:VkVideoEncodeH264PictureInfoKHR structure, and
    slink:VkVideoEncodeH264PictureInfoKHR::pname:pStdPictureInfo->pRefLists
    is not `NULL`, then each element of the code:RefPicList0 and
    code:RefPicList1 array members of the
    code:StdVideoEncodeH264ReferenceListsInfo structure pointed to by
    slink:VkVideoEncodeH264PictureInfoKHR::pname:pStdPictureInfo->pRefLists
    must: either be code:STD_VIDEO_H264_NO_REFERENCE_PICTURE or must: equal
    the pname:slotIndex member of one of the elements of
    pname:pEncodeInfo->pReferenceSlots
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08353]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, the pname:pNext
    chain of pname:pEncodeInfo includes a
    slink:VkVideoEncodeH264PictureInfoKHR structure, and
    pname:pEncodeInfo->referenceSlotCount is greater than zero, then the
    pname:slotIndex member of each element of
    pname:pEncodeInfo->pReferenceSlots must: equal one of the elements of
    the code:RefPicList0 or code:RefPicList1 array members of the
    code:StdVideoEncodeH264ReferenceListsInfo structure pointed to by
    slink:VkVideoEncodeH264PictureInfoKHR::pname:pStdPictureInfo->pRefLists
  * [[VUID-vkCmdEncodeVideoKHR-maxPPictureL0ReferenceCount-08340]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR and
    slink:VkVideoEncodeH264CapabilitiesKHR::pname:maxPPictureL0ReferenceCount
    is zero, as returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR
    for the video profile the bound video session was created with, then
    pname:h264PictureType and each element of pname:h264L0PictureTypes and
    pname:h264L1PictureTypes must: not be code:STD_VIDEO_H264_PICTURE_TYPE_P
  * [[VUID-vkCmdEncodeVideoKHR-maxBPictureL0ReferenceCount-08341]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR and
    slink:VkVideoEncodeH264CapabilitiesKHR::pname:maxBPictureL0ReferenceCount
    and slink:VkVideoEncodeH264CapabilitiesKHR::pname:maxL1ReferenceCount
    are both zero, as returned by
    flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video profile the
    bound video session was created with, then pname:h264PictureType and
    each element of pname:h264L0PictureTypes and pname:h264L1PictureTypes
    must: not be code:STD_VIDEO_H264_PICTURE_TYPE_B
  * [[VUID-vkCmdEncodeVideoKHR-flags-08342]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR and
    slink:VkVideoEncodeH264CapabilitiesKHR::pname:flags does not include
    ename:VK_VIDEO_ENCODE_H264_CAPABILITY_B_FRAME_IN_L0_LIST_BIT_KHR, as
    returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video
    profile the bound video session was created with, then each element of
    pname:h264L0PictureTypes must: not be code:STD_VIDEO_H264_PICTURE_TYPE_B
  * [[VUID-vkCmdEncodeVideoKHR-flags-08343]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR and
    slink:VkVideoEncodeH264CapabilitiesKHR::pname:flags does not include
    ename:VK_VIDEO_ENCODE_H264_CAPABILITY_B_FRAME_IN_L1_LIST_BIT_KHR, as
    returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video
    profile the bound video session was created with, then each element of
    pname:h264L1PictureTypes must: not be code:STD_VIDEO_H264_PICTURE_TYPE_B
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08230]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then the pname:pNext
    chain of pname:pEncodeInfo must: include a
    slink:VkVideoEncodeH265PictureInfoKHR structure
  * [[VUID-vkCmdEncodeVideoKHR-StdVideoH265VideoParameterSet-08231]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then the bound video
    session parameters object must: contain a
    code:StdVideoH265VideoParameterSet entry with
    pname:vps_video_parameter_set_id matching
    code:StdVideoEncodeH265PictureInfo::pname:sps_video_parameter_set_id
    that is provided in the pname:pStdPictureInfo member of the
    slink:VkVideoEncodeH265PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo
  * [[VUID-vkCmdEncodeVideoKHR-StdVideoH265SequenceParameterSet-08232]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then the bound video
    session parameters object must: contain a
    code:StdVideoH265SequenceParameterSet entry with
    pname:sps_video_parameter_set_id and pname:sps_seq_parameter_set_id
    matching
    code:StdVideoEncodeH265PictureInfo::pname:sps_video_parameter_set_id and
    code:StdVideoEncodeH265PictureInfo::pname:pps_seq_parameter_set_id,
    respectively, that are provided in the pname:pStdPictureInfo member of
    the slink:VkVideoEncodeH265PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo
  * [[VUID-vkCmdEncodeVideoKHR-StdVideoH265PictureParameterSet-08233]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then the bound video
    session parameters object must: contain a
    code:StdVideoH265PictureParameterSet entry with
    pname:sps_video_parameter_set_id, pname:pps_seq_parameter_set_id, and
    pname:pps_pic_parameter_set_id matching
    code:StdVideoEncodeH265PictureInfo::pname:sps_video_parameter_set_id,
    code:StdVideoEncodeH265PictureInfo::pname:pps_seq_parameter_set_id, and
    code:StdVideoEncodeH265PictureInfo::pname:pps_pic_parameter_set_id,
    respectively, that are provided in the pname:pStdPictureInfo member of
    the slink:VkVideoEncodeH265PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo
  * [[VUID-vkCmdEncodeVideoKHR-pEncodeInfo-08234]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR and
    pname:pEncodeInfo->pSetupReferenceSlot is not `NULL`, then the
    pname:pNext chain of pname:pEncodeInfo->pSetupReferenceSlot must:
    include a slink:VkVideoEncodeH265DpbSlotInfoKHR structure
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08235]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then the pname:pNext
    chain of each element of pname:pEncodeInfo->pReferenceSlots must:
    include a slink:VkVideoEncodeH265DpbSlotInfoKHR structure
  * [[VUID-vkCmdEncodeVideoKHR-constantQp-08272]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR and the current
    <<encode-rate-control-modes,rate control mode>> is not
    ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DISABLED_BIT_KHR, then
    slink:VkVideoEncodeH265NaluSliceSegmentInfoKHR::pname:constantQp must:
    be zero for each element of the pname:pNaluSliceSegmentEntries member of
    the slink:VkVideoEncodeH265PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo
  * [[VUID-vkCmdEncodeVideoKHR-constantQp-08273]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR and the current
    <<encode-rate-control-modes,rate control mode>> is
    ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DISABLED_BIT_KHR, then
    slink:VkVideoEncodeH265NaluSliceSegmentInfoKHR::pname:constantQp must:
    be between slink:VkVideoEncodeH265CapabilitiesKHR::pname:minQp and
    slink:VkVideoEncodeH265CapabilitiesKHR::pname:maxQp, as returned by
    flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video profile the
    bound video session was created with, for each element of the
    pname:pNaluSliceSegmentEntries member of the
    slink:VkVideoEncodeH265PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo
  * [[VUID-vkCmdEncodeVideoKHR-constantQp-08274]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR and
    slink:VkVideoEncodeH265CapabilitiesKHR::pname:flags does not include
    ename:VK_VIDEO_ENCODE_H265_CAPABILITY_PER_SLICE_SEGMENT_CONSTANT_QP_BIT_KHR,
    as returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the
    video profile the bound video session was created with, then
    slink:VkVideoEncodeH265NaluSliceSegmentInfoKHR::pname:constantQp must:
    have the same value for each element of the
    pname:pNaluSliceSegmentEntries member of the
    slink:VkVideoEncodeH264PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo
  * [[VUID-vkCmdEncodeVideoKHR-naluSliceSegmentEntryCount-08307]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then the
    pname:naluSliceSegmentEntryCount member of the
    slink:VkVideoEncodeH265PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo must: be less than or equal to
    pname:minCodingBlockExtent.width multiplied by
    pname:minCodingBlockExtent.height
  * [[VUID-vkCmdEncodeVideoKHR-naluSliceSegmentEntryCount-08313]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR and
    slink:VkVideoEncodeH265CapabilitiesKHR::pname:flags does not include
    ename:VK_VIDEO_ENCODE_H265_CAPABILITY_ROW_UNALIGNED_SLICE_SEGMENT_BIT_KHR,
    as returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the
    video profile the bound video session was created with, then the
    pname:naluSliceSegmentEntryCount member of the
    slink:VkVideoEncodeH265PictureInfoKHR structure included in the
    pname:pNext chain of pname:pEncodeInfo must: be less than or equal to
    pname:minCodingBlockExtent.height
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08354]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, the pname:pNext
    chain of pname:pEncodeInfo includes a
    slink:VkVideoEncodeH265PictureInfoKHR structure, and
    pname:pEncodeInfo->referenceSlotCount is greater than zero, then
    slink:VkVideoEncodeH265PictureInfoKHR::pname:pStdPictureInfo->pRefLists
    must: not be `NULL`
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08344]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, the pname:pNext
    chain of pname:pEncodeInfo includes a
    slink:VkVideoEncodeH265PictureInfoKHR structure, and
    slink:VkVideoEncodeH265PictureInfoKHR::pname:pStdPictureInfo->pRefLists
    is not `NULL`, then each element of the code:RefPicList0 and
    code:RefPicList1 array members of the
    code:StdVideoEncodeH265ReferenceListsInfo structure pointed to by
    slink:VkVideoEncodeH265PictureInfoKHR::pname:pStdPictureInfo->pRefLists
    must: either be code:STD_VIDEO_H265_NO_REFERENCE_PICTURE or must: equal
    the pname:slotIndex member of one of the elements of
    pname:pEncodeInfo->pReferenceSlots
  * [[VUID-vkCmdEncodeVideoKHR-pNext-08355]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, the pname:pNext
    chain of pname:pEncodeInfo includes a
    slink:VkVideoEncodeH265PictureInfoKHR structure, and
    pname:pEncodeInfo->referenceSlotCount is greater than zero, then the
    pname:slotIndex member of each element of
    pname:pEncodeInfo->pReferenceSlots must: equal one of the elements of
    the code:RefPicList0 or code:RefPicList1 array members of the
    code:StdVideoEncodeH265ReferenceListsInfo structure pointed to by
    slink:VkVideoEncodeH265PictureInfoKHR::pname:pStdPictureInfo->pRefLists
  * [[VUID-vkCmdEncodeVideoKHR-maxPPictureL0ReferenceCount-08345]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR and
    slink:VkVideoEncodeH265CapabilitiesKHR::pname:maxPPictureL0ReferenceCount
    is zero, as returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR
    for the video profile the bound video session was created with, then
    pname:h265PictureType and each element of pname:h265L0PictureTypes and
    pname:h265L1PictureTypes must: not be code:STD_VIDEO_H265_PICTURE_TYPE_P
  * [[VUID-vkCmdEncodeVideoKHR-maxBPictureL0ReferenceCount-08346]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR and
    slink:VkVideoEncodeH265CapabilitiesKHR::pname:maxBPictureL0ReferenceCount
    and slink:VkVideoEncodeH265CapabilitiesKHR::pname:maxL1ReferenceCount
    are both zero, as returned by
    flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video profile the
    bound video session was created with, then pname:h265PictureType and
    each element of pname:h265L0PictureTypes and pname:h265L1PictureTypes
    must: not be code:STD_VIDEO_H265_PICTURE_TYPE_B
  * [[VUID-vkCmdEncodeVideoKHR-flags-08347]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR and
    slink:VkVideoEncodeH265CapabilitiesKHR::pname:flags does not include
    ename:VK_VIDEO_ENCODE_H265_CAPABILITY_B_FRAME_IN_L0_LIST_BIT_KHR, as
    returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video
    profile the bound video session was created with, then each element of
    pname:h265L0PictureTypes must: not be code:STD_VIDEO_H264_PICTURE_TYPE_B
  * [[VUID-vkCmdEncodeVideoKHR-flags-08348]]
    If the bound video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR and
    slink:VkVideoEncodeH265CapabilitiesKHR::pname:flags does not include
    ename:VK_VIDEO_ENCODE_H265_CAPABILITY_B_FRAME_IN_L1_LIST_BIT_KHR, as
    returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the video
    profile the bound video session was created with, then each element of
    pname:h265L1PictureTypes must: not be code:STD_VIDEO_H265_PICTURE_TYPE_B
endif::VK_KHR_video_encode_h265[]
****

include::{generated}/validity/protos/vkCmdEncodeVideoKHR.adoc[]
--

[open,refpage='VkVideoEncodeInfoKHR',desc='Structure specifying video encode parameters',type='structs']
--
The sname:VkVideoEncodeInfoKHR structure is defined as:

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

  * pname:sType is a elink:VkStructureType value identifying this structure.
  * pname:pNext is a pointer to a structure extending this structure.
  * pname:flags is reserved for future use.
  * pname:dstBuffer is the destination video bitstream buffer to write the
    encoded bitstream to.
  * pname:dstBufferOffset is the starting offset in bytes from the start of
    pname:dstBuffer to write the encoded bitstream to.
  * pname:dstBufferRange is the maximum bitstream size in bytes that can: be
    written to pname:dstBuffer, starting from pname:dstBufferOffset.
  * pname:srcPictureResource is the video picture resource to use as the
    <<encode-input-picture,encode input picture>>.
  * pname:pSetupReferenceSlot is `NULL` or a pointer to a
    slink:VkVideoReferenceSlotInfoKHR structure specifying the
    <<encode-reconstructed-picture-info,reconstructed picture information>>.
  * pname:referenceSlotCount is the number of elements in the
    pname:pReferenceSlots array.
  * pname:pReferenceSlots is `NULL` or a pointer to an array of
    slink:VkVideoReferenceSlotInfoKHR structures describing the DPB slots
    and corresponding <<reference-picture,reference picture>> resources to
    use in this video encode operation (the set of
    <<active-reference-pictures, active reference pictures>>).
  * pname:precedingExternallyEncodedBytes is the number of bytes externally
    encoded by the application to the video bitstream and is used to update
    the internal state of the implementation's <<encode-rate-control,rate
    control>> algorithm to account for the bitrate budget consumed by these
    externally encoded bytes.

.Valid Usage
****
  * [[VUID-VkVideoEncodeInfoKHR-dstBuffer-08236]]
    pname:dstBuffer must: have been created with
    ename:VK_BUFFER_USAGE_VIDEO_ENCODE_DST_BIT_KHR set
  * [[VUID-VkVideoEncodeInfoKHR-dstBufferOffset-08237]]
    pname:dstBufferOffset must: be less than the size of pname:dstBuffer
  * [[VUID-VkVideoEncodeInfoKHR-dstBufferRange-08238]]
    pname:dstBufferRange must: be less than or equal to the size of
    pname:dstBuffer minus pname:dstBufferOffset
  * [[VUID-VkVideoEncodeInfoKHR-pSetupReferenceSlot-08239]]
    If pname:pSetupReferenceSlot is not `NULL`, then its pname:slotIndex
    member must: not be negative
  * [[VUID-VkVideoEncodeInfoKHR-pSetupReferenceSlot-08240]]
    If pname:pSetupReferenceSlot is not `NULL`, then its
    pname:pPictureResource must: not be `NULL`
  * [[VUID-VkVideoEncodeInfoKHR-slotIndex-08241]]
    The pname:slotIndex member of each element of pname:pReferenceSlots
    must: not be negative
  * [[VUID-VkVideoEncodeInfoKHR-pPictureResource-08242]]
    The pname:pPictureResource member of each element of
    pname:pReferenceSlots must: not be `NULL`
****

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

[open,refpage='VkVideoEncodeFlagsKHR',desc='Reserved for future use',type='flags']
--
include::{generated}/api/flags/VkVideoEncodeFlagsKHR.adoc[]

tlink:VkVideoEncodeFlagsKHR is a bitmask type for setting a mask, but is
currently reserved for future use.
--


[[encode-rate-control]]
== Video Encode Rate Control

The size of the encoded bitstream data produced by video encode operations
is a function of the following set of constraints:

  * The capabilities of the compression algorithms defined and employed by
    the used video compression standard;
  * Restrictions imposed by the selected <<video-profiles,video profile>>
    according to the rules defined by the used video compression standard;
  * Further restrictions imposed by the <<video-coding-capabilities,
    capabilities>> supported by the implementation for the selected
    <<video-profiles,video profile>>;
  * The image data in the <<encode-input-picture,encode input picture>> and
    the set of <<active-reference-pictures,active reference pictures>> (as
    these affect the effectiveness of the compression algorithms employed by
    the video encode operations);
  * The set of codec-specific and codec-independent encoding parameters
    provided by the application.

These also inherently define the set of decoder capabilities required for
reconstructing and processing the picture data in the encoded bitstream.

[[encode-bitrate]]
Video coding uses _bitrate_ as the quantitative metric associated with
encoded bitstream data size which expresses the rate at which video
bitstream data can: be transferred or processed, measured in number of bits
per second.
This bitrate is both a function of the encoded bitstream data size of the
encoded pictures as well as the _frame rate_ used by the video sequence.

Rate control algorithms are used by video encode operations to enable
adjusting encoding parameters to achieve a target bitrate, or otherwise
directly or indirectly control the bitrate of the generated video bitstream
data.
These algorithms are usually not defined by the used video compression
standard, although some video compression standards do provide non-normative
guidelines for implementations.

Accordingly, this specification does not mandate implementations to produce
identical encoded bitstream data outputs in response to video encode
operations, however, it does define a set of codec-independent and
codec-specific parameters that enable the application to control the
behavior of the rate control algorithms supported by the implementation.
Some of these parameters guarantee certain implementation behavior while
others provide guidance for implementations to apply various rate control
heuristics.

[NOTE]
.Note
====
Applications need to make sure that they configure rate control parameters
appropriately and that they follow the promises made to the implementation
through parameters providing guidance for the implementation's rate control
algorithms and heuristics in order to be able to get the desired rate
control behavior and to be able to hit the set bitrate targets.
In addition, the behavior of rate control may also differ across
implementations even if the capabilities of the used video profile match
between those implementations.
This may happen due to implementations applying different rate control
algorithms or heuristics internally, and thus even the same set of guidance
parameter values may have different effects on the rate control behavior
across implementations.
====


[[encode-rate-control-modes]]
=== Rate Control Modes

After a video session is reset to the <<video-session-uninitialized,initial
state>>, the default behavior and parameters of video encode rate control
are entirely implementation-dependent and the application cannot: affect the
bitrate or quality parameters of the encoded bitstream data produced by
video encode operations unless the application changes the rate control
configuration of the video session, as described in the
<<video-coding-control,Video Coding Control>> section.

For each supported <<video-profiles,video profile>>, the implementation may:
expose a set of _rate control modes_ that are available for use by the
application when encoding bitstreams targeting that video profile.
These modes allow using different rate control algorithms that fall into one
of the following two categories:

  1. Per-operation rate control
  2. Stream-level rate control

In case of _per-operation rate control_, the bitrate of the generated video
bitstream data is indirectly controlled by quality, size, or other encoding
parameters specified by the application for each individual video encode
operation.

In case of _stream-level rate control_, the application can: directly
specify target bitrates besides other encoding parameters to control the
behavior of the rate control algorithm used by the implementation across
multiple video encode operations.

[open,refpage='VkVideoEncodeRateControlModeFlagBitsKHR',desc='Video encode rate control modes',type='enums']
--
The rate control modes are defined with the following enums:

include::{generated}/api/enums/VkVideoEncodeRateControlModeFlagBitsKHR.adoc[]

  * ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DEFAULT_KHR specifies the use of
    implementation-specific rate control.
  * ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DISABLED_BIT_KHR specifies that
    rate control is disabled and the application will specify per-operation
    rate control parameters controlling the encoding quality.
    In this mode implementations will encode pictures independently of the
    output bitrate of prior video encode operations.
ifdef::VK_KHR_video_encode_h264[]
  ** When using an <<encode-h264-profile,H.264 encode profile>>,
     implementations will use the QP value specified in
     slink:VkVideoEncodeH264NaluSliceInfoKHR::pname:constantQp to control
     the quality of the encoded picture.
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  ** When using an <<encode-h265-profile,H.265 encode profile>>,
     implementations will use the QP value specified in
     slink:VkVideoEncodeH265NaluSliceSegmentInfoKHR::pname:constantQp to
     control the quality of the encoded picture.
endif::VK_KHR_video_encode_h265[]
  * ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_CBR_BIT_KHR specifies the use of
    constant bitrate (CBR) rate control mode.
    In this mode the implementation will attempt to produce the encoded
    bitstream at a constant bitrate while conforming to the constraints of
    other rate control parameters.
  * ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_VBR_BIT_KHR specifies the use of
    variable bitrate (VBR) rate control mode.
    In this mode the implementation will produce the encoded bitstream at a
    variable bitrate according to the constraints of other rate control
    parameters.
--

[open,refpage='VkVideoEncodeRateControlModeFlagsKHR',desc='Bitmask of VkVideoEncodeRateControlModeFlagBitsKHR', type='flags']
--
include::{generated}/api/flags/VkVideoEncodeRateControlModeFlagsKHR.adoc[]

tname:VkVideoEncodeRateControlModeFlagsKHR is a bitmask type for setting a
mask of zero or more elink:VkVideoEncodeRateControlModeFlagBitsKHR.
--


[[encode-leaky-bucket-model]]
=== Leaky Bucket Model

Video encoding implementations use the _leaky bucket model_ for stream-level
rate control.
The leaky bucket is a concept referring to the interface between the video
encoder and the consumer (for example, a network connection), where the
video encoder produces encoded bitstream data corresponding to the encoded
pictures and adds them in the leaky bucket while its content are drained by
the consumer.

Analogously, a similar leaky bucket is considered to exist at the input
interface of a video decoder, into which encoded bitstream data is
continuously added and is subsequently consumed by the video decoder.
It is desirable to avoid overflowing or underflowing this leaky bucked
because:

  * In case of an underflow, the video decoder will be unable to consume
    encoded bitstream data in order to decode pictures (and optionally
    display them).
  * In case of an overflow, the leaky bucket will be unable to accommodate
    more encoded bitstream data and such data may: need to be thrown away,
    leading to the loss of the corresponding encoded pictures.

These requirements can: be satisfied by imposing various constraints on the
encoder-side leaky bucket to avoid its overflow or underflow, depending on
the used rate control algorithm and codec parameters.
However, enumerating these constraints is outside the scope of this
specification.

The term _virtual buffer_ is often used as an alternative to refer to the
leaky bucket.

This virtual buffer model is defined by the following parameters:

  * The bitrate (`R`) at which the encoded bitstream is expected to be
    processed.
  * The size (`B`) of the virtual buffer.
  * The initial occupancy (`F`) of the virtual buffer.

In this model the virtual buffer is used to smooth out fluctuations in the
bitrate of the encoded bitstream over time without experiencing buffer
overflow or underflow, as long as the bitrate of the encoded stream does not
diverge from the target bitrate for extended periods of time.

This buffering may: inherently impose a processing delay, as the goal of the
model is to enable decoders maintain a consistent processing rate of an
encoded bitstream with varying data rate.

The initial or start-up delay (`D`) is computed as:

  {empty}:: [eq]#`D` = `F` / `R`#

[NOTE]
.Note
====
Applications need to configure the virtual buffer with sufficient size to
avoid or minimize buffer overflows and underflows while also keeping it
small enough to meet their latency goals.
====


[[encode-rate-control-layers]]
=== Rate Control Layers

Some video compression standards and <<video-profiles,video profiles>> allow
associating encoded pictures with specific _video coding layers_.
The name, identification, and semantics associated with such video coding
layers are defined by the corresponding video compression standards.

Analogously, stream-level rate control can: be configured to use one or more
_rate control layers_:

  * When a single rate control layer is configured, it is applied to all
    encoded pictures, regardless of the picture's video coding layer.
    In this case the distribution of the available bitrate budget across
    video coding layers is implementation-dependent.
  * When multiple rate control layers are configured, each rate control
    layer is applied to the corresponding video coding layer, i.e. only
    across encoded pictures pertaining to the corresponding video coding
    layer.

Individual rate control layers are identified using _layer indices_ between
zero and `N-1`, where `N` is the number of active rate control layers.

Rate control layers are only applicable when using
<<encode-rate-control-modes,stream-level rate control modes>>.


[[encode-rate-control-state]]
=== Rate Control State

Rate control state is maintained by the implementation in the
<<video-session, video session>> objects and its parameters are specified
using an instance of the sname:VkVideoEncodeRateControlInfoKHR structure.
The complete rate control state of a video session is defined by the
following set of parameters:

  * The values of the members of the slink:VkVideoEncodeRateControlInfoKHR
    structure used to configure the rate control state.
  * The values of the members of any
    slink:VkVideoEncodeRateControlLayerInfoKHR structures specified in
    slink:VkVideoEncodeRateControlInfoKHR::pname:pLayers used to configure
    the state of individual <<encode-rate-control-layers,rate control
    layers>>.
ifdef::VK_KHR_video_encode_h264[]
  * If the video session was created with an <<encode-h264-profile,H.264
    encode profile>>:
  ** The values of the members of the
     slink:VkVideoEncodeH264RateControlInfoKHR structure, if one is
     specified in the pname:pNext chain of the
     slink:VkVideoEncodeRateControlInfoKHR used to configure the rate
     control state.
  ** The values of the members of any
     slink:VkVideoEncodeH264RateControlLayerInfoKHR structures included in
     the pname:pNext chain of a slink:VkVideoEncodeRateControlLayerInfoKHR
     structure used to configure the state of a rate control layer.
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  * If the video session was created with an <<encode-h265-profile,H.265
    encode profile>>:
  ** The values of the members of the
     slink:VkVideoEncodeH265RateControlInfoKHR structure, if one is
     specified in the pname:pNext chain of the
     slink:VkVideoEncodeRateControlInfoKHR used to configure the rate
     control state.
  ** The values of the members of any
     slink:VkVideoEncodeH265RateControlLayerInfoKHR structures included in
     the pname:pNext chain of a slink:VkVideoEncodeRateControlLayerInfoKHR
     structure used to configure the state of a rate control layer.
endif::VK_KHR_video_encode_h265[]

[[encode-rate-control-state-matching]]
Two rate control states match if all the parameters listed above match
between them.

[open,refpage='VkVideoEncodeRateControlInfoKHR',desc='Structure to set encode stream rate control parameters',type='structs']
--
The sname:VkVideoEncodeRateControlInfoKHR structure is defined as:

include::{generated}/api/structs/VkVideoEncodeRateControlInfoKHR.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:flags is reserved for future use.
  * pname:rateControlMode is a elink:VkVideoEncodeRateControlModeFlagBitsKHR
    value specifying the <<encode-rate-control-modes,rate control mode>>.
  * pname:layerCount specifies the number of <<encode-rate-control-layers,
    rate control layers>> to use.
  * pname:pLayers is a pointer to an array of pname:layerCount
    slink:VkVideoEncodeRateControlLayerInfoKHR structures, each specifying
    the rate control configuration of the corresponding rate control layer.
  * pname:virtualBufferSizeInMs is the size in milliseconds of the virtual
    buffer used by the implementation's rate control algorithm for the
    <<encode-leaky-bucket-model,leaky bucket model>>, with respect to the
    average bitrate of the stream calculated by summing the values of the
    pname:averageBitrate members of the elements of the pname:pLayers array.
  * pname:initialVirtualBufferSizeInMs is the initial occupancy in
    milliseconds of the virtual buffer used by the implementation's rate
    control algorithm for the <<encode-leaky-bucket-model,leaky bucket
    model>>.

If pname:layerCount is zero then the values of pname:virtualBufferSizeInMs
and pname:initialVirtualBufferSizeInMs are ignored.

This structure can: be specified in the following places:

  * In the pname:pNext chain of slink:VkVideoBeginCodingInfoKHR to specify
    the current rate control state expected to be configured when beginning
    a <<video-coding-scope,video coding scope>>.
  * In the pname:pNext chain of slink:VkVideoCodingControlInfoKHR to change
    the rate control configuration of the bound video session.

Including this structure in the pname:pNext chain of
slink:VkVideoCodingControlInfoKHR and including
ename:VK_VIDEO_CODING_CONTROL_ENCODE_RATE_CONTROL_BIT_KHR in
slink:VkVideoCodingControlInfoKHR::pname:flags enables updating the rate
control configuration of the bound video session.
This replaces the entire rate control configuration of the bound video
session and may: reset the state of all enabled rate control layers to an
initial state according to the codec-specific rate control semantics defined
in the corresponding sections listed below.

When pname:layerCount is greater than one, multiple
<<encode-rate-control-layers,rate control layers>> are configured, and each
rate control layer is applied to the corresponding video coding layer
identified by the index of the corresponding element of pname:pLayer.

ifdef::VK_KHR_video_encode_h264[]
  * If the video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, then this index
    specifies the H.264 temporal layer ID of the video coding layer the rate
    control layer is applied to.
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  * If the video session was created with the video codec operation
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, then this index
    specifies the H.265 temporal ID of the video coding layer the rate
    control layer is applied to.
endif::VK_KHR_video_encode_h265[]

Additional structures providing codec-specific rate control parameters can:
be included in the pname:pNext chain of sname:VkVideoCodingControlInfoKHR
depending on the <<video-profiles,video profile>> the bound video session
was created.
For further details see:

  * <<video-coding-control,Video Coding Control>>
ifdef::VK_KHR_video_encode_h264[]
  * <<encode-h264-rate-control,H.264 Encode Rate Control>>
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  * <<encode-h265-rate-control,H.265 Encode Rate Control>>
endif::VK_KHR_video_encode_h265[]

The new rate control configuration takes effect when the corresponding
flink:vkCmdControlVideoCodingKHR is executed on the device, and only impacts
video encode operations that follow in execution order.

.Valid Usage
****
  * [[VUID-VkVideoEncodeRateControlInfoKHR-rateControlMode-08248]]
    If pname:rateControlMode is
    ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DEFAULT_KHR or
    ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DISABLED_BIT_KHR, then
    pname:layerCount must: be `0`
  * [[VUID-VkVideoEncodeRateControlInfoKHR-rateControlMode-08275]]
    If pname:rateControlMode is
    ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_CBR_BIT_KHR or
    ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_VBR_BIT_KHR, then
    pname:layerCount must: be greater than `0`
  * [[VUID-VkVideoEncodeRateControlInfoKHR-rateControlMode-08244]]
    If pname:rateControlMode is not
    ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DEFAULT_KHR, then it must:
    specify one of the bits included in
    slink:VkVideoEncodeCapabilitiesKHR::pname:rateControlModes, as returned
    by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the used video
    profile
  * [[VUID-VkVideoEncodeRateControlInfoKHR-layerCount-08245]]
    pname:layerCount member must: be less than or equal to
    slink:VkVideoEncodeCapabilitiesKHR::pname:maxRateControlLayers, as
    returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the used
    video profile
  * [[VUID-VkVideoEncodeRateControlInfoKHR-pLayers-08276]]
    For each element of pname:pLayers, its pname:averageBitrate member must:
    be between `1` and slink:VkVideoEncodeCapabilitiesKHR::pname:maxBitrate,
    as returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the
    used video profile
  * [[VUID-VkVideoEncodeRateControlInfoKHR-pLayers-08277]]
    For each element of pname:pLayers, its pname:maxBitrate member must: be
    between `1` and slink:VkVideoEncodeCapabilitiesKHR::pname:maxBitrate, as
    returned by flink:vkGetPhysicalDeviceVideoCapabilitiesKHR for the used
    video profile
  * [[VUID-VkVideoEncodeRateControlInfoKHR-rateControlMode-08356]]
    If pname:rateControlMode is
    ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_CBR_BIT_KHR, then for each
    element of pname:pLayers, its pname:averageBitrate member must: equal
    its pname:maxBitrate member
  * [[VUID-VkVideoEncodeRateControlInfoKHR-rateControlMode-08278]]
    If pname:rateControlMode is
    ename:VK_VIDEO_ENCODE_RATE_CONTROL_MODE_VBR_BIT_KHR, then for each
    element of pname:pLayers, its pname:averageBitrate member must: be less
    than or equal to its pname:maxBitrate member
  * [[VUID-VkVideoEncodeRateControlInfoKHR-layerCount-08357]]
    If pname:layerCount is not zero, then pname:virtualBufferSizeInMs must:
    be greater than zero
  * [[VUID-VkVideoEncodeRateControlInfoKHR-layerCount-08358]]
    If pname:layerCount is not zero, then pname:initialVirtualBufferSizeInMs
    must: be less than pname:virtualBufferSizeInMs
ifdef::VK_KHR_video_encode_h264[]
  * [[VUID-VkVideoEncodeRateControlInfoKHR-videoCodecOperation-07022]]
    If the pname:videoCodecOperation of the used video profile is
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR, the pname:pNext
    chain this structure is included in also includes an instance of the
    slink:VkVideoEncodeH264RateControlInfoKHR structure, and
    pname:layerCount is greater than `1`, then pname:layerCount must: equal
    slink:VkVideoEncodeH264RateControlInfoKHR::pname:temporalLayerCount
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  * [[VUID-VkVideoEncodeRateControlInfoKHR-videoCodecOperation-07025]]
    If the pname:videoCodecOperation of the used video profile is
    ename:VK_VIDEO_CODEC_OPERATION_ENCODE_H265_BIT_KHR, the pname:pNext
    chain this structure is included in also includes an instance of the
    slink:VkVideoEncodeH265RateControlInfoKHR structure, and
    pname:layerCount is greater than `1`, then pname:layerCount must: equal
    slink:VkVideoEncodeH265RateControlInfoKHR::pname:subLayerCount
endif::VK_KHR_video_encode_h265[]
****

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

[open,refpage='VkVideoEncodeRateControlFlagsKHR',desc='Reserved for future use',type='flags']
--
include::{generated}/api/flags/VkVideoEncodeRateControlFlagsKHR.adoc[]

tname:VkVideoEncodeRateControlFlagsKHR is a bitmask type for setting a mask,
but currently reserved for future use.
--


==== Rate Control Layer State

The configuration of individual rate control layers is specified using an
instance of the sname:VkVideoEncodeRateControlLayerInfoKHR structure.

[open,refpage='VkVideoEncodeRateControlLayerInfoKHR',desc='Structure to set encode per-layer rate control parameters',type='structs']
--
The sname:VkVideoEncodeRateControlLayerInfoKHR structure is defined as:

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

  * pname:sType is a elink:VkStructureType value identifying this structure.
  * pname:pNext is a pointer to a structure extending this structure.
  * pname:averageBitrate is the average <<encode-bitrate,bitrate>> to be
    targeted by the implementation's rate control algorithm.
  * pname:maxBitrate is the peak <<encode-bitrate,bitrate>> to be targeted
    by the implementation's rate control algorithm.
  * pname:frameRateNumerator is the numerator of the frame rate assumed by
    the implementation's rate control algorithm.
  * pname:frameRateDenominator is the denominator of the frame rate assumed
    by the implementation's rate control algorithm.

[NOTE]
.Note
====
The ability of the implementation's rate control algorithm to be able to
match the requested average and/or peak bitrates may: be limited by the set
of other codec-independent and codec-specific rate control parameters
specified by the application, the input content, as well as the application
conforming to the rate control guidance provided to the implementation, as
described <<encode-rate-control,earlier>>.
====

Additional structures providing codec-specific rate control parameters can:
be included in the pname:pNext chain of
sname:VkVideoEncodeRateControlLayerInfoKHR depending on the
<<video-profiles,video profile>> the bound video session was created with.
For further details see:

  * <<video-coding-control,Video Coding Control>>
ifdef::VK_KHR_video_encode_h264[]
  * <<encode-h264-rate-control,H.264 Encode Rate Control>>
endif::VK_KHR_video_encode_h264[]
ifdef::VK_KHR_video_encode_h265[]
  * <<encode-h265-rate-control,H.265 Encode Rate Control>>
endif::VK_KHR_video_encode_h265[]

.Valid Usage
****
  * [[VUID-VkVideoEncodeRateControlLayerInfoKHR-frameRateNumerator-08350]]
    pname:frameRateNumerator must: be greater than zero
  * [[VUID-VkVideoEncodeRateControlLayerInfoKHR-frameRateDenominator-08351]]
    pname:frameRateDenominator must: be greater than zero
****

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