VkVideoEncodeAV1PictureInfoKHR

The VkVideoEncodeAV1PictureInfoKHR structure is defined as:

typedef struct VkVideoEncodeAV1PictureInfoKHR {
    VkStructureType sType;
    const void* pNext;
    VkVideoEncodeAV1PredictionModeKHR predictionMode;
    VkVideoEncodeAV1RateControlGroupKHR rateControlGroup;
    uint32_t constantQIndex;
    const StdVideoEncodeAV1PictureInfo* pStdPictureInfo;
    int32_t referenceNameSlotIndices[VK_MAX_VIDEO_AV1_REFERENCES_PER_FRAME_KHR];
    VkBool32 primaryReferenceCdfOnly;
    VkBool32 generateObuExtensionHeader;
} VkVideoEncodeAV1PictureInfoKHR;

• sType is a VkStructureType value identifying this structure.
• pNext is NULL or a pointer to a structure extending this structure.
• predictionMode specifies the AV1 prediction mode to use for the encoded frame.
• rateControlGroup specifies the AV1 rate control group to use for the encoded frame when the current rate control mode is not VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DISABLED_BIT_KHR. Otherwise it is ignored.
• constantQIndex is the quantizer index to use for the encoded frame if the current rate control mode configured for the video session is VK_VIDEO_ENCODE_RATE_CONTROL_MODE_DISABLED_BIT_KHR.
• pStdPictureInfo is a pointer to a StdVideoEncodeAV1PictureInfo structure specifying AV1 picture information.
• referenceNameSlotIndices is an array of seven (VK_MAX_VIDEO_AV1_REFERENCES_PER_FRAME_KHR, which is equal to the Video Std definition STD_VIDEO_AV1_REFS_PER_FRAME) signed integer values specifying the index of the DPB slot or a negative integer value for each AV1 reference name used for inter coding. In particular, the DPB slot index for the AV1 reference name frame is specified in referenceNameSlotIndices[frame - STD_VIDEO_AV1_REFERENCE_NAME_LAST_FRAME].
• primaryReferenceCdfOnly controls whether the primary reference frame indicated by the value of pStdPictureInfo→primary_ref_frame is used only for CDF data reference, as defined in sections 6.8.2 of the AV1 Specification. If set to VK_TRUE, then the primary reference frame’s picture data will not be used for sample prediction.
• generateObuExtensionHeader controls whether OBU extension headers are generated into the target bitstream, as defined in sections 5.3.1, 5.3.2, and 5.3.3 of the AV1 Specification.

This structure is specified in the pNext chain of the VkVideoEncodeInfoKHR structure passed to vkCmdEncodeVideoKHR to specify the codec-specific picture information for an AV1 encode operation.

Encode Input Picture Information

When this structure is specified in the pNext chain of the VkVideoEncodeInfoKHR structure passed to vkCmdEncodeVideoKHR, the information related to the encode input picture is defined as follows:

• The image subregion used is determined according to the AV1 Encode Picture Data Access section.
• The encode input picture is associated with the AV1 picture information provided in pStdPictureInfo.

Std Picture Information

The members of the StdVideoEncodeAV1PictureInfo structure pointed to by pStdPictureInfo are interpreted as follows:

• flags.reserved and reserved1 are used only for padding purposes and are otherwise ignored;
• pSegmentation must be NULL

  AV1 segmentation is currently not supported in video encode operations. Accordingly, the application needs to set flags.segmentation_enabled to 0 and pSegmentation to NULL.

• pTileInfo is NULL or a pointer to a StdVideoAV1TileInfo structure specifying AV1 tile parameters;
• the StdVideoAV1Quantization structure pointed to by pQuantization is interpreted as follows:
  • flags.reserved is used only for padding purposes and is otherwise ignored;
  • all other members of StdVideoAV1Quantization are interpreted as defined in section 6.8.11 of the AV1 Specification;
• the StdVideoAV1LoopFilter structure pointed to by pLoopFilter is interpreted as follows:
  • flags.reserved is used only for padding purposes and is otherwise ignored;
  • update_ref_delta is a bitmask where bit index i is interpreted as the value of update_ref_delta corresponding to element i of loop_filter_ref_deltas as defined in section 6.8.10 of the AV1 Specification;
  • update_mode_delta is a bitmask where bit index i is interpreted as the value of update_mode_delta corresponding to element i of loop_filter_mode_deltas as defined in section 6.8.10 of the AV1 Specification;
  • all other members of StdVideoAV1LoopFilter are interpreted as defined in section 6.8.10 of the AV1 Specification;
• if flags.enable_cdef is set in the active sequence header, then the members of the StdVideoAV1CDEF structure pointed to by pCDEF are interpreted as follows:
  • cdef_y_sec_strength and cdef_uv_sec_strength are the bitstream values of the corresponding syntax elements defined in section 5.9.19 of the AV1 Specification;
  • all other members of StdVideoAV1CDEF are interpreted as defined in section 6.10.14 of the AV1 Specification;
• if flags.UsesLr is set in the active sequence header, then the StdVideoAV1LoopRestoration structure pointed to by pLoopRestoration is interpreted as follows:
  • LoopRestorationSize[plane] is interpreted as log2(size) - 5, where size is the value of LoopRestorationSize[plane] as defined in section 6.10.15 of the AV1 Specification;
  • all other members of StdVideoAV1LoopRestoration are defined as in section 6.10.15 of the AV1 Specification;
• the members of the StdVideoAV1GlobalMotion structure provided in global_motion are interpreted as defined in section 7.10 of the AV1 Specification;
• pExtensionHeader is NULL or a pointer to a StdVideoEncodeAV1ExtensionHeader structure whose temporal_id and spatial_id members specify the temporal and spatial layer ID of the reference frame, respectively (these IDs are encoded into the OBU extension header if VkVideoEncodeAV1PictureInfoKHR::generateObuExtensionHeader is set to VK_TRUE for the encode operation);
• if flags.buffer_removal_time_present_flag is set, then pBufferRemovalTimes is a pointer to an array of N number of unsigned integer values specifying the elements of the buffer_removal_time array, as defined in section 6.8.2 of the AV1 Specification, where N is the number of operating points specified for the active sequence header through VkVideoEncodeAV1SessionParametersCreateInfoKHR::stdOperatingPointCount;
• all other members are interpreted as defined in section 6.8 of the AV1 Specification.

Reference picture setup is controlled by the value of StdVideoEncodeAV1PictureInfo::refresh_frame_flags. If it is not zero and a reconstructed picture is specified, then the latter is used as the target of picture reconstruction to activate the DPB slot specified in pEncodeInfo→pSetupReferenceSlot→slotIndex. If StdVideoEncodeAV1PictureInfo::refresh_frame_flags is zero, but a reconstructed picture is specified, then the corresponding picture reference associated with the DPB slot is invalidated, as described in the DPB Slot States section.

Std Tile Parameters

Specifying AV1 tile parameters is optional. If StdVideoEncodeAV1PictureInfo::pTileInfo is NULL, then the implementation determines the values of AV1 tile parameters defined in section 6.8.14 of the AV1 Specification in an implementation-dependent manner. If StdVideoEncodeAV1PictureInfo::pTileInfo is not NULL, then the members of the StdVideoAV1TileInfo structure pointed to by StdVideoEncodeAV1PictureInfo::pTileInfo are interpreted as follows:

• flags.reserved and reserved1 are used only for padding purposes and are otherwise ignored;
• TileCols and TileRows specify the number of tile columns and tile rows as defined in section 6.8.14 of the AV1 Specification;
• tile_size_bytes_minus_1 is ignored, as its value, as defined in section 6.8.14 of the AV1 Specification, is determined as the result of the encoding process;
• pMiColStarts and pMiRowStarts are ignored, as the elements of the MiColStarts and MiRowStarts arrays defined in section 6.8.14 of the AV1 Specification are determined by the implementation based on the tile widths and heights determined by the implementation or specified through the pWidthInSbsMinus1 and pHeightInSbsMinus1 arrays, respectively;
• pWidthInSbsMinus1 is NULL or a pointer to an array of TileCols number of unsigned integers that corresponds to width_in_sbs_minus_1 defined in section 6.8.14 of the AV1 Specification;
• pHeightInSbsMinus1 is NULL or is a pointer to an array of TileRows number of unsigned integers that corresponds to height_in_sbs_minus_1 defined in section 6.8.14 of the AV1 Specification;
• all other members of StdVideoAV1TileInfo are interpreted as defined in section 6.8.14 of the AV1 Specification.

If flags.uniform_tile_spacing_flag is set, then pWidthInSbsMinus1 and pHeightInSbsMinus1 are ignored.

If flags.uniform_tile_spacing_flag is not set and pWidthInSbsMinus1 is NULL, then the width of individual tile columns is determined in an implementation-dependent manner.

If flags.uniform_tile_spacing_flag is not set and pHeightInSbsMinus1 is NULL, then the height of individual tile rows is determined in an implementation-dependent manner.

Active Parameter Sets

The active sequence header is the AV1 sequence header stored in the bound video session parameters object.