# VkVideoDecodeAV1DpbSlotInfoKHR(3) Manual Page

## Name

VkVideoDecodeAV1DpbSlotInfoKHR - Structure specifies AV1 DPB information when decoding a frame

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## C Specification

The `VkVideoDecodeAV1DpbSlotInfoKHR` structure is defined as:

    // Provided by VK_KHR_video_decode_av1
    typedef struct VkVideoDecodeAV1DpbSlotInfoKHR {
        VkStructureType                          sType;
        const void*                              pNext;
        const StdVideoDecodeAV1ReferenceInfo*    pStdReferenceInfo;
    } VkVideoDecodeAV1DpbSlotInfoKHR;

## 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 `StdVideoDecodeAV1ReferenceInfo` structure specifying AV1 reference information.

## Description

This structure is specified in the `pNext` chain of VkVideoDecodeInfoKHR::`pSetupReferenceSlot`, if not `NULL`, and the `pNext` chain of the elements of VkVideoDecodeInfoKHR::`pReferenceSlots` to specify the codec-specific reference picture information for an AV1 decode operation.

Active Reference Picture Information

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

  - The image subregion used is determined according to the AV1 Decode Picture Data Access section.

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

  - The reference picture is associated with the AV1 reference information provided in `pStdReferenceInfo`.

Reconstructed Picture Information

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

  - The image subregion used is determined according to the AV1 Decode 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 VkVideoDecodeInfoKHR::`pSetupReferenceSlot->slotIndex`.

  - The reconstructed picture is associated with the AV1 reference information provided in `pStdReferenceInfo`.

Std Reference Information

  The members of the `StdVideoDecodeAV1ReferenceInfo` structure pointed to by `pStdReferenceInfo` are interpreted as follows:

  - `flags.reserved` and `reserved1` are used only for padding purposes and are otherwise ignored;

  - `flags.disable_frame_end_update_cdf` is interpreted as defined in section 6.8.2 of the AV1 Specification;

  - `flags.segmentation_enabled` is interpreted as defined in section 6.8.13 of the AV1 Specification;

  - `frame_type` is interpreted as defined in section 6.8.2 of the AV1 Specification;

    Note | The `frame_type` member is defined with the type `uint8_t`, but it takes the same values defined in the `StdVideoAV1FrameType` enumeration type as `StdVideoDecodeAV1PictureInfo`::`frame_type`.

  - `RefFrameSignBias` is a bitmask where bit index i corresponds to `RefFrameSignBias[i]` as defined in section 6.8.2 of the AV1 Specification;

  - `OrderHint` is interpreted as defined in section 6.8.2 of the AV1 Specification;

  - `SavedOrderHints` is interpreted as defined in section 7.20 of the AV1 Specification.

    Note | When the AV1 reference information is provided for the reconstructed picture, certain parameters (e.g. `frame_type`) are specified both in the AV1 picture information and in the AV1 reference information. This is necessary because unlike the AV1 picture information, which is only used for the purposes of the video decode operation in question, the AV1 reference information specified for the reconstructed picture may be associated with the activated DPB slot, meaning that some implementations may maintain it as part of the reference picture metadata corresponding to the video picture resource associated with the DPB slot. When the AV1 reference information is provided for an active reference picture, the specified parameters correspond to the parameters specified when the DPB slot was activated (set up) with the reference picture, as usual, in order to communicate these parameters for implementations that do not maintain any subset of these parameters as part of the DPB slot’s reference picture metadata.

Valid Usage (Implicit)

- VUID-VkVideoDecodeAV1DpbSlotInfoKHR-sType-sType
  `sType` must be `VK_STRUCTURE_TYPE_VIDEO_DECODE_AV1_DPB_SLOT_INFO_KHR`

- VUID-VkVideoDecodeAV1DpbSlotInfoKHR-pStdReferenceInfo-parameter
  `pStdReferenceInfo` must be a valid pointer to a valid `StdVideoDecodeAV1ReferenceInfo` value

## See Also

VK_KHR_video_decode_av1, 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