# VkVideoEncodeH264DpbSlotInfoKHR(3) Manual Page

## Name

VkVideoEncodeH264DpbSlotInfoKHR - Structure specifies H.264 encode DPB picture information

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## C Specification

The VkVideoEncodeH264DpbSlotInfoKHR structure is defined as:

    // Provided by VK_KHR_video_encode_h264
    typedef struct VkVideoEncodeH264DpbSlotInfoKHR {
        VkStructureType                           sType;
        const void*                               pNext;
        const StdVideoEncodeH264ReferenceInfo*    pStdReferenceInfo;
    } VkVideoEncodeH264DpbSlotInfoKHR;

## Members

- `sType` is a VkStructureType value identifying this structure.

- `pNext` is `NULL` or a pointer to a structure extending this structure.

- `pStdReferenceInfo` is a pointer to a `StdVideoEncodeH264ReferenceInfo` structure specifying H.264 reference information.

## Description

This structure is specified in the `pNext` chain of VkVideoEncodeInfoKHR::`pSetupReferenceSlot`, if not `NULL`, and the `pNext` chain of the elements of VkVideoEncodeInfoKHR::`pReferenceSlots` to specify the codec-specific reference picture information for an H.264 encode operation.

Active Reference Picture Information

  When this structure is specified in the `pNext` chain of the elements of VkVideoEncodeInfoKHR::`pReferenceSlots`, one element is added to the list of active reference pictures used by the video encode operation for each element of VkVideoEncodeInfoKHR::`pReferenceSlots` as follows:

  - The image subregion used is determined according to the H.264 Encode Picture Data Access section.

  - The reference picture is associated with the DPB slot index specified in the `slotIndex` member of the corresponding element of VkVideoEncodeInfoKHR::`pReferenceSlots`.

  - The reference picture is associated with the H.264 reference information provided in `pStdReferenceInfo`.

Reconstructed Picture Information

  When this structure is specified in the `pNext` chain of VkVideoEncodeInfoKHR::`pSetupReferenceSlot`, the information related to the reconstructed picture is defined as follows:

  - The image subregion used is determined according to the H.264 Encode Picture Data Access section.

  - If reference picture setup is requested, then the reconstructed picture is used to activate the DPB slot with the index specified in VkVideoEncodeInfoKHR::`pSetupReferenceSlot->slotIndex`.

  - The reconstructed picture is associated with the H.264 reference information provided in `pStdReferenceInfo`.

Std Reference Information

  The members of the `StdVideoEncodeH264ReferenceInfo` structure pointed to by `pStdReferenceInfo` are interpreted as follows:

  - `flags.reserved` is used only for padding purposes and is otherwise ignored;

  - `flags.used_for_long_term_reference` is used to indicate whether the picture is marked as “used for long-term reference” as defined in section 8.2.5.1 of the ITU-T H.264 Specification;

  - `primary_pic_type` as defined in section 7.4.2 of the ITU-T H.264 Specification;

  - `long_term_pic_num` and `long_term_frame_idx` as defined in section 7.4.3 of the ITU-T H.264 Specification;

  - `temporal_id` as defined in section G.7.4.1.1 of the ITU-T H.264 Specification;

  - all other members are interpreted as defined in section 8.2 of the ITU-T H.264 Specification.

Valid Usage (Implicit)

- VUID-VkVideoEncodeH264DpbSlotInfoKHR-sType-sType
  `sType` must be `VK_STRUCTURE_TYPE_VIDEO_ENCODE_H264_DPB_SLOT_INFO_KHR`

- VUID-VkVideoEncodeH264DpbSlotInfoKHR-pStdReferenceInfo-parameter
  `pStdReferenceInfo` must be a valid pointer to a valid `StdVideoEncodeH264ReferenceInfo` value

## See Also

VK_KHR_video_encode_h264, VkStructureType

## Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

## Copyright

Copyright 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0