VkVideoDecodeAV1DpbSlotInfoKHR

The VkVideoDecodeAV1DpbSlotInfoKHR structure is defined as:

typedef struct VkVideoDecodeAV1DpbSlotInfoKHR {
    VkStructureType sType;
    const void* pNext;
    const StdVideoDecodeAV1ReferenceInfo* pStdReferenceInfo;
} VkVideoDecodeAV1DpbSlotInfoKHR;

• 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.

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;

  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.

  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.