VkVideoEncodeAV1CapabilitiesKHR

When calling vkGetPhysicalDeviceVideoCapabilitiesKHR to query the capabilities for an AV1 encode profile, the VkVideoCapabilitiesKHR::pNext chain must include a VkVideoEncodeAV1CapabilitiesKHR structure that will be filled with the profile-specific capabilities.

The VkVideoEncodeAV1CapabilitiesKHR structure is defined as:

typedef struct VkVideoEncodeAV1CapabilitiesKHR {
    VkStructureType sType;
    void* pNext;
    VkVideoEncodeAV1CapabilityFlagsKHR flags;
    StdVideoAV1Level maxLevel;
    VkExtent2D codedPictureAlignment;
    VkExtent2D maxTiles;
    VkExtent2D minTileSize;
    VkExtent2D maxTileSize;
    VkVideoEncodeAV1SuperblockSizeFlagsKHR superblockSizes;
    uint32_t maxSingleReferenceCount;
    uint32_t singleReferenceNameMask;
    uint32_t maxUnidirectionalCompoundReferenceCount;
    uint32_t maxUnidirectionalCompoundGroup1ReferenceCount;
    uint32_t unidirectionalCompoundReferenceNameMask;
    uint32_t maxBidirectionalCompoundReferenceCount;
    uint32_t maxBidirectionalCompoundGroup1ReferenceCount;
    uint32_t maxBidirectionalCompoundGroup2ReferenceCount;
    uint32_t bidirectionalCompoundReferenceNameMask;
    uint32_t maxTemporalLayerCount;
    uint32_t maxSpatialLayerCount;
    uint32_t maxOperatingPoints;
    uint32_t minQIndex;
    uint32_t maxQIndex;
    VkBool32 prefersGopRemainingFrames;
    VkBool32 requiresGopRemainingFrames;
    VkVideoEncodeAV1StdFlagsKHR stdSyntaxFlags;
} VkVideoEncodeAV1CapabilitiesKHR;

• sType is a VkStructureType value identifying this structure.
• pNext is NULL or a pointer to a structure extending this structure.
• flags is a bitmask of VkVideoEncodeAV1CapabilityFlagBitsKHR indicating supported AV1 encoding capabilities.
• maxLevel is a StdVideoAV1Level value indicating the maximum AV1 level supported by the profile, as defined in section A.3 of the AV1 Specification.
• codedPictureAlignment indicates the alignment at which the implementation will code pictures. This capability does not impose any valid usage constraints on the application. However, depending on the codedExtent of the encode input picture resource, this capability may result in a change of the resolution of the encoded picture, as described in more detail below.
• maxTiles indicates the maximum number of AV1 tile columns and rows the implementation supports.
• minTileSize indicates the minimum extent of individual AV1 tiles the implementation supports.
• maxTileSize indicates the maximum extent of individual AV1 tiles the implementation supports.
• superblockSizes is a bitmask of VkVideoEncodeAV1SuperblockSizeFlagBitsKHR values indicating the supported AV1 superblock sizes.
• maxSingleReferenceCount indicates the maximum number of reference pictures the implementation supports when using single reference prediction mode.
• singleReferenceNameMask is a bitmask of supported AV1 reference names when using single reference prediction mode.
• maxUnidirectionalCompoundReferenceCount indicates the maximum number of reference pictures the implementation supports when using unidirectional compound prediction mode.
• maxUnidirectionalCompoundGroup1ReferenceCount indicates the maximum number of reference pictures the implementation supports when using unidirectional compound prediction mode from reference frame group 1, as defined in section 6.10.24 of the AV1 Specification.
• unidirectionalCompoundReferenceNameMask is a bitmask of supported AV1 reference names when using unidirectional compound prediction mode.
• maxBidirectionalCompoundReferenceCount indicates the maximum number of reference pictures the implementation supports when using bidirectional compound prediction mode.
• maxBidirectionalCompoundGroup1ReferenceCount indicates the maximum number of reference pictures the implementation supports when using bidirectional compound prediction mode from reference frame group 1, as defined in section 6.10.24 of the AV1 Specification.
• maxBidirectionalCompoundGroup2ReferenceCount indicates the maximum number of reference pictures the implementation supports when using bidirectional compound prediction mode from reference frame group 2, as defined in section 6.10.24 of the AV1 Specification.
• bidirectionalCompoundReferenceNameMask is a bitmask of supported AV1 reference names when using bidirectional compound prediction mode.
• maxTemporalLayerCount indicates the maximum number of AV1 temporal layers supported by the implementation.
• maxSpatialLayerCount indicates the maximum number of AV1 spatial layers supported by the implementation.
• maxOperatingPoints indicates the maximum number of AV1 operating points supported by the implementation.
• minQIndex indicates the minimum quantizer index value supported.
• maxQIndex indicates the maximum quantizer index value supported.
• prefersGopRemainingFrames indicates that the implementation’s rate control algorithm prefers the application to specify the number of frames in each AV1 rate control group
  remaining in the current group of pictures when beginning a video coding scope.
• requiresGopRemainingFrames indicates that the implementation’s rate control algorithm requires the application to specify the number of frames in each AV1 rate control group
  remaining in the current group of pictures when beginning a video coding scope.
• stdSyntaxFlags is a bitmask of VkVideoEncodeAV1StdFlagBitsKHR indicating capabilities related to AV1 syntax elements.

singleReferenceNameMask, unidirectionalCompoundReferenceNameMask, and bidirectionalCompoundReferenceNameMask are encoded such that when bit index i is set, it indicates support for the AV1 reference name

STD_VIDEO_AV1_REFERENCE_NAME_LAST_FRAME + i.

codedPictureAlignment provides information about implementation limitations to encode arbitrary resolutions. In particular, some implementations may not be able to generate bitstreams aligned to the requirements of the AV1 Specification (8x8). In such cases, the implementation may override the width and height of the bitstream, in order to produce a bitstream compliant to the AV1 Specification. If such an override occurs, the encoded resolution of the coded picture is enlargened, with the texel values used for the texel coordinates outside of the bounds of the codedExtent of the encode input picture resource being first governed by the rules regarding the encode input picture granularity. Any texel values outside of the region described by the encode input picture granularity are implementation-defined. Implementations should use well-defined values to minimize impact on the produced encoded content.