VkVideoEncodeH265CapabilitiesKHR

When calling vkGetPhysicalDeviceVideoCapabilitiesKHR to query the capabilities for an H.265 encode profile, the VkVideoCapabilitiesKHR::pNext chain must include a VkVideoEncodeH265CapabilitiesKHR structure that will be filled with the profile-specific capabilities.

The VkVideoEncodeH265CapabilitiesKHR structure is defined as:

typedef struct VkVideoEncodeH265CapabilitiesKHR {
    VkStructureType sType;
    void* pNext;
    VkVideoEncodeH265CapabilityFlagsKHR flags;
    StdVideoH265LevelIdc maxLevelIdc;
    uint32_t maxSliceSegmentCount;
    VkExtent2D maxTiles;
    VkVideoEncodeH265CtbSizeFlagsKHR ctbSizes;
    VkVideoEncodeH265TransformBlockSizeFlagsKHR transformBlockSizes;
    uint32_t maxPPictureL0ReferenceCount;
    uint32_t maxBPictureL0ReferenceCount;
    uint32_t maxL1ReferenceCount;
    uint32_t maxSubLayerCount;
    VkBool32 expectDyadicTemporalSubLayerPattern;
    int32_t minQp;
    int32_t maxQp;
    VkBool32 prefersGopRemainingFrames;
    VkBool32 requiresGopRemainingFrames;
    VkVideoEncodeH265StdFlagsKHR stdSyntaxFlags;
} VkVideoEncodeH265CapabilitiesKHR;

• 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 VkVideoEncodeH265CapabilityFlagBitsKHR indicating supported H.265 encoding capabilities.
• maxLevelIdc is a StdVideoH265LevelIdc value indicating the maximum H.265 level supported by the profile, where enum constant STD_VIDEO_H265_LEVEL_IDC_<major>_<minor> identifies H.265 level <major>.<minor> as defined in section A.4 of the ITU-T H.265 Specification.
• maxSliceSegmentCount indicates the maximum number of slice segments that can be encoded for a single picture. Further restrictions may apply to the number of slice segments that can be encoded for a single picture depending on other capabilities and codec-specific rules.
• maxTiles indicates the maximum number of H.265 tile columns and rows, as defined in sections 3.175 and 3.176 of the ITU-T H.265 Specification that can be encoded for a single picture. Further restrictions may apply to the number of H.265 tiles that can be encoded for a single picture depending on other capabilities and codec-specific rules.
• ctbSizes is a bitmask of VkVideoEncodeH265CtbSizeFlagBitsKHR describing the supported CTB sizes.
• transformBlockSizes is a bitmask of VkVideoEncodeH265TransformBlockSizeFlagBitsKHR describing the supported transform block sizes.
• maxPPictureL0ReferenceCount indicates the maximum number of reference pictures the implementation supports in the reference list L0 for P pictures.

  As implementations may override the reference lists, maxPPictureL0ReferenceCount does not limit the number of elements that the application can specify in the L0 reference list for P pictures. However, if maxPPictureL0ReferenceCount is zero, then the use of P pictures is not allowed. In case of H.265 encoding, pictures can be encoded using only forward prediction even if P pictures are not supported, as the ITU-T H.265 Specification supports generalized P & B frames (also known as low delay B frames) whereas B frames can refer to past frames through both the L0 and L1 reference lists.

• maxBPictureL0ReferenceCount indicates the maximum number of reference pictures the implementation supports in the reference list L0 for B pictures.
• maxL1ReferenceCount indicates the maximum number of reference pictures the implementation supports in the reference list L1 if encoding of B pictures is supported.

  As implementations may override the reference lists, maxBPictureL0ReferenceCount and maxL1ReferenceCount does not limit the number of elements that the application can specify in the L0 and L1 reference lists for B pictures. However, if maxBPictureL0ReferenceCount and maxL1ReferenceCount are both zero, then the use of B pictures is not allowed.

• maxSubLayerCount indicates the maximum number of H.265 sub-layers supported by the implementation.
• expectDyadicTemporalSubLayerPattern indicates that the implementation’s rate control algorithms expect the application to use a dyadic temporal sub-layer pattern when encoding multiple temporal sub-layers.
• minQp indicates the minimum QP value supported.
• maxQp indicates the maximum QP value supported.
• prefersGopRemainingFrames indicates that the implementation’s rate control algorithm prefers the application to specify the number of frames of each type 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 of each type remaining in the current group of pictures when beginning a video coding scope.
• stdSyntaxFlags is a bitmask of VkVideoEncodeH265StdFlagBitsKHR indicating capabilities related to H.265 syntax elements.