# VK_KHR_video_encode_h264(3) Manual Page

## Name

VK_KHR_video_encode_h264 - device extension

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## Registered Extension Number

39

## Revision

14

## Ratification Status

Ratified

## Extension and Version Dependencies

VK_KHR_video_encode_queue

## Contact

- Ahmed Abdelkhalek [GitHub]aabdelkh

## Extension Proposal

VK_KHR_video_encode_h264

## Other Extension Metadata

Last Modified Date

  2023-12-05

IP Status

  No known IP claims.

Contributors

  - Ahmed Abdelkhalek, AMD

  - George Hao, AMD

  - Jake Beju, AMD

  - Peter Fang, AMD

  - Ping Liu, Intel

  - Srinath Kumarapuram, NVIDIA

  - Tony Zlatinski, NVIDIA

  - Ravi Chaudhary, NVIDIA

  - Yang Liu, AMD

  - Daniel Rakos, RasterGrid

  - Aidan Fabius, Core Avionics & Industrial Inc.

  - Lynne Iribarren, Independent

## Description

This extension builds upon the `VK_KHR_video_encode_queue` extension by adding support for encoding elementary video stream sequences compliant with the H.264/AVC video compression standard.

Note | This extension was promoted to `KHR` from the provisional extension `VK_EXT_video_encode_h264`.

## New Structures

- VkVideoEncodeH264FrameSizeKHR

- VkVideoEncodeH264NaluSliceInfoKHR

- VkVideoEncodeH264QpKHR

- Extending VkVideoBeginCodingInfoKHR:

  - VkVideoEncodeH264GopRemainingFrameInfoKHR

- Extending VkVideoCapabilitiesKHR:

  - VkVideoEncodeH264CapabilitiesKHR

- Extending VkVideoCodingControlInfoKHR, VkVideoBeginCodingInfoKHR:

  - VkVideoEncodeH264RateControlInfoKHR

- Extending VkVideoEncodeInfoKHR:

  - VkVideoEncodeH264PictureInfoKHR

- Extending VkVideoEncodeQualityLevelPropertiesKHR:

  - VkVideoEncodeH264QualityLevelPropertiesKHR

- Extending VkVideoEncodeRateControlLayerInfoKHR:

  - VkVideoEncodeH264RateControlLayerInfoKHR

- Extending VkVideoEncodeSessionParametersFeedbackInfoKHR:

  - VkVideoEncodeH264SessionParametersFeedbackInfoKHR

- Extending VkVideoEncodeSessionParametersGetInfoKHR:

  - VkVideoEncodeH264SessionParametersGetInfoKHR

- Extending VkVideoProfileInfoKHR, VkQueryPoolCreateInfo:

  - VkVideoEncodeH264ProfileInfoKHR

- Extending VkVideoReferenceSlotInfoKHR:

  - VkVideoEncodeH264DpbSlotInfoKHR

- Extending VkVideoSessionCreateInfoKHR:

  - VkVideoEncodeH264SessionCreateInfoKHR

- Extending VkVideoSessionParametersCreateInfoKHR:

  - VkVideoEncodeH264SessionParametersCreateInfoKHR

- Extending VkVideoSessionParametersUpdateInfoKHR:

  - VkVideoEncodeH264SessionParametersAddInfoKHR

## New Enums

- VkVideoEncodeH264CapabilityFlagBitsKHR

- VkVideoEncodeH264RateControlFlagBitsKHR

- VkVideoEncodeH264StdFlagBitsKHR

## New Bitmasks

- VkVideoEncodeH264CapabilityFlagsKHR

- VkVideoEncodeH264RateControlFlagsKHR

- VkVideoEncodeH264StdFlagsKHR

## New Enum Constants

- `VK_KHR_VIDEO_ENCODE_H264_EXTENSION_NAME`

- `VK_KHR_VIDEO_ENCODE_H264_SPEC_VERSION`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_CAPABILITIES_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_DPB_SLOT_INFO_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_GOP_REMAINING_FRAME_INFO_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_NALU_SLICE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_PICTURE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_PROFILE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_QUALITY_LEVEL_PROPERTIES_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_RATE_CONTROL_INFO_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_RATE_CONTROL_LAYER_INFO_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_SESSION_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_SESSION_PARAMETERS_ADD_INFO_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_SESSION_PARAMETERS_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_SESSION_PARAMETERS_FEEDBACK_INFO_KHR`

  - `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_SESSION_PARAMETERS_GET_INFO_KHR`

- Extending VkVideoCodecOperationFlagBitsKHR:

  - `VK_VIDEO_CODEC_OPERATION_ENCODE_H264_BIT_KHR`

## Version History

- Revision 0, 2018-7-23 (Ahmed Abdelkhalek)

  - Initial draft

- Revision 0.5, 2020-02-13 (Tony Zlatinski)

  - General Spec cleanup

  - Added DPB structures

  - Change the VCL frame encode structure

  - Added a common Non-VCL Picture Paramarameters structure

- Revision 1, 2021-03-29 (Tony Zlatinski)

  - Spec and API updates

- Revision 2, August 1 2021 (Srinath Kumarapuram)

  - Rename `VkVideoEncodeH264CapabilitiesFlagsEXT` to `VkVideoEncodeH264CapabilityFlagsEXT` and `VkVideoEncodeH264CapabilitiesFlagsEXT` to `VkVideoEncodeH264CapabilityFlagsEXT`, following Vulkan naming conventions.

- Revision 3, 2021-12-08 (Ahmed Abdelkhalek)

  - Rate control updates

- Revision 4, 2022-02-04 (Ahmed Abdelkhalek)

  - Align VkVideoEncodeH264VclFrameInfoEXT structure to similar one in VK_EXT_video_encode_h265 extension

- Revision 5, 2022-02-10 (Ahmed Abdelkhalek)

  - Updates to encode capability interface

- Revision 6, 2022-03-16 (Ahmed Abdelkhalek)

  - Relocate Std header version reporting/requesting from this extension to VK_KHR_video_queue extension.

  - Remove redundant maxPictureSizeInMbs from VkVideoEncodeH264SessionCreateInfoEXT.

  - Remove the now empty VkVideoEncodeH264SessionCreateInfoEXT.

- Revision 7, 2022-04-06 (Ahmed Abdelkhalek)

  - Add capability flag to report support to use B frame in L1 reference list.

  - Add capability flag to report support for disabling SPS direct_8x8_inference_flag.

- Revision 8, 2022-07-18 (Daniel Rakos)

  - Replace `VkVideoEncodeH264RateControlStructureFlagBitsEXT` bit enum with `VkVideoEncodeH264RateControlStructureEXT` enum

  - Rename `VkVideoEncodeH264ProfileEXT` to `VkVideoEncodeH264ProfileInfoEXT`

  - Rename `VkVideoEncodeH264ReferenceListsEXT` to `VkVideoEncodeH264ReferenceListsInfoEXT`

  - Rename `VkVideoEncodeH264EmitPictureParametersEXT` to `VkVideoEncodeH264EmitPictureParametersInfoEXT`

  - Rename `VkVideoEncodeH264NaluSliceEXT` to `VkVideoEncodeH264NaluSliceInfoEXT`

- Revision 9, 2022-09-18 (Daniel Rakos)

  - Rename `spsStdCount`, `pSpsStd`, `ppsStdCount`, and `pPpsStd` to `stdSPSCount`, `pStdSPSs`, `stdPPSCount`, and `pStdPPSs`, respectively, in `VkVideoEncodeH264SessionParametersAddInfoEXT`

  - Rename `maxSpsStdCount` and `maxPpsStdCount` to `maxStdSPSCount` and `maxStdPPSCount`, respectively, in `VkVideoEncodeH264SessionParametersCreateInfoEXT`

- Revision 10, 2023-03-06 (Daniel Rakos)

  - Removed `VkVideoEncodeH264EmitPictureParametersInfoEXT`

  - Changed member types in `VkVideoEncodeH264CapabilitiesEXT` and `VkVideoEncodeH264ReferenceListsInfoEXT` from `uint8_t` to `uint32_t`

  - Changed the type of `VkVideoEncodeH264RateControlInfoEXT::temporalLayerCount` and `VkVideoEncodeH264RateControlLayerInfoEXT::temporalLayerId` from `uint8_t` to `uint32_t`

  - Removed `VkVideoEncodeH264InputModeFlagsEXT` and `VkVideoEncodeH264OutputModeFlagsEXT` as we only support frame-in-frame-out mode for now

  - Rename `pCurrentPictureInfo` in `VkVideoEncodeH264VclFrameInfoEXT` to `pStdPictureInfo`

  - Rename `pSliceHeaderStd` in `VkVideoEncodeH264NaluSliceInfoEXT` to `pStdSliceHeader`

  - Rename `pReferenceFinalLists` in `VkVideoEncodeH264VclFrameInfoEXT` and `VkVideoEncodeH264NaluSliceInfoEXT` to `pStdReferenceFinalLists`

  - Removed the `slotIndex` member of `VkVideoEncodeH264DpbSlotInfoEXT` and changed it to be chained to `VkVideoReferenceSlotInfoKHR`

  - Replaced `VkVideoEncodeH264ReferenceListsInfoEXT` with the new Video Std header structure `StdVideoEncodeH264ReferenceLists` that also includes data previously part of the now removed `StdVideoEncodeH264RefMemMgmtCtrlOperations` structure

  - Added new capability flag `VK_VIDEO_ENCODE_H264_CAPABILITY_DIFFERENT_REFERENCE_FINAL_LISTS_BIT_EXT`

- Revision 11, 2023-05-22 (Daniel Rakos)

  - Renamed `VkVideoEncodeH264VclFrameInfoEXT` to `VkVideoEncodeH264PictureInfoEXT`

  - Added `VkVideoEncodeH264PictureInfoEXT::generatePrefixNalu` and `VK_VIDEO_ENCODE_H264_CAPABILITY_GENERATE_PREFIX_NALU_BIT_EXT` to enable the generation of H.264 prefix NALUs when supported by the implementation

  - Removed `VkVideoEncodeH264RateControlLayerInfoEXT::temporalLayerId`

  - Added `expectDyadicTemporalLayerPattern` capability

  - Added the `VkVideoEncodeH264SessionParametersGetInfoEXT` structure to identify the H.264 parameter sets to retrieve encoded parameter data for, and the `VkVideoEncodeH264SessionParametersFeedbackInfoEXT` structure to retrieve H.264 parameter set override information when using the new `vkGetEncodedVideoSessionParametersKHR` command

  - Added `VkVideoEncodeH264NaluSliceInfoEXT::constantQp` to specify per-slice constant QP when rate control mode is `VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DISABLED_BIT_KHR`

  - Added `VkVideoEncodeH264QualityLevelPropertiesEXT` for retrieving H.264 specific quality level recommendations

  - Replaced `VkVideoEncodeH264RateControlStructureEXT` enum with the flags type `VkVideoEncodeH264RateControlFlagsEXT` and bits defined in `VkVideoEncodeH264RateControlFlagBitsEXT` and added HRD compliance flag

  - Removed `useInitialRcQp` and `initialRcQp` members of `VkVideoEncodeH264RateControlLayerInfoEXT`

  - Added `prefersGopRemainingFrames` and `requiresGopRemainingFrames`, and the new `VkVideoEncodeH264GopRemainingFrameInfoEXT` structure to allow specifying remaining frames of each type in the rate control GOP

  - Added `maxTemporalLayers`, `maxQp`, and `minQp` capabilities

  - Added `maxLevelIdc` capability and new `VkVideoEncodeH264SessionCreateInfoEXT` structure to specify upper bounds on the H.264 level of the produced video bitstream

  - Moved capability flags specific to codec syntax restrictions from `VkVideoEncodeH264CapabilityFlagsEXT` to the new `VkVideoEncodeH264StdFlagsEXT` which is now included as a separate `stdSyntaxFlags` member in `VkVideoEncodeH264CapabilitiesEXT`

  - Removed codec syntax override values from `VkVideoEncodeH264CapabilitiesEXT`

  - Removed `VkVideoEncodeH264NaluSliceInfoEXT::mbCount` and `VK_VIDEO_ENCODE_H264_CAPABILITY_SLICE_MB_COUNT_BIT_EXT`

  - Replaced `VK_VIDEO_ENCODE_H264_CAPABILITY_MULTIPLE_SLICES_PER_FRAME_BIT_EXT` with the new `maxSliceCount` capability

  - Removed capability flag `VK_VIDEO_ENCODE_H264_CAPABILITY_DIFFERENT_REFERENCE_FINAL_LISTS_BIT_EXT` and removed `pStdReferenceFinalLists` members from the `VkVideoEncodeH264PictureInfoEXT` and `VkVideoEncodeH264NaluSliceInfoEXT` structures as reference lists info is now included in `pStdPictureInfo`

  - Added capability flag `VK_VIDEO_ENCODE_H264_CAPABILITY_B_FRAME_IN_L0_LIST_BIT_EXT`

- Revision 12, 2023-07-19 (Daniel Rakos)

  - Added video std capability flags `VK_VIDEO_ENCODE_H264_STD_SLICE_QP_DELTA_BIT_EXT` and `VK_VIDEO_ENCODE_H264_STD_DIFFERENT_SLICE_QP_DELTA_BIT_EXT`

  - Fixed optionality of the array members of `VkVideoEncodeH264SessionParametersAddInfoEXT`

  - Fixed optionality of `VkVideoEncodeH264RateControlInfoEXT::flags`

- Revision 13, 2023-09-04 (Daniel Rakos)

  - Change extension from `EXT` to `KHR`

  - Extension is no longer provisional

- Revision 14, 2023-12-05 (Daniel Rakos)

  - Condition reference picture setup based on the value of `StdVideoEncodeH264PictureInfo::flags.is_reference`

## See Also

No cross-references are available

## Document Notes

For more information, see the Vulkan Specification

This page is a generated document. Fixes and changes should be made to the generator scripts, not directly.

## Copyright

Copyright 2014-2025 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0