VkVideoEncodeH264CapabilityFlagBitsKHR(3)

C Specification

Bits which may be set in VkVideoEncodeH264CapabilitiesKHR::flags, indicating the H.264 encoding capabilities supported, are:

// Provided by VK_KHR_video_encode_h264
typedef enum VkVideoEncodeH264CapabilityFlagBitsKHR {
    VK_VIDEO_ENCODE_H264_CAPABILITY_HRD_COMPLIANCE_BIT_KHR = 0x00000001,
    VK_VIDEO_ENCODE_H264_CAPABILITY_PREDICTION_WEIGHT_TABLE_GENERATED_BIT_KHR = 0x00000002,
    VK_VIDEO_ENCODE_H264_CAPABILITY_ROW_UNALIGNED_SLICE_BIT_KHR = 0x00000004,
    VK_VIDEO_ENCODE_H264_CAPABILITY_DIFFERENT_SLICE_TYPE_BIT_KHR = 0x00000008,
    VK_VIDEO_ENCODE_H264_CAPABILITY_B_FRAME_IN_L0_LIST_BIT_KHR = 0x00000010,
    VK_VIDEO_ENCODE_H264_CAPABILITY_B_FRAME_IN_L1_LIST_BIT_KHR = 0x00000020,
    VK_VIDEO_ENCODE_H264_CAPABILITY_PER_PICTURE_TYPE_MIN_MAX_QP_BIT_KHR = 0x00000040,
    VK_VIDEO_ENCODE_H264_CAPABILITY_PER_SLICE_CONSTANT_QP_BIT_KHR = 0x00000080,
    VK_VIDEO_ENCODE_H264_CAPABILITY_GENERATE_PREFIX_NALU_BIT_KHR = 0x00000100,
  // Provided by VK_KHR_video_encode_h264 with VK_KHR_video_encode_intra_refresh
    VK_VIDEO_ENCODE_H264_CAPABILITY_B_PICTURE_INTRA_REFRESH_BIT_KHR = 0x00000400,
  // Provided by VK_KHR_video_encode_h264 with VK_KHR_video_encode_quantization_map
    VK_VIDEO_ENCODE_H264_CAPABILITY_MB_QP_DIFF_WRAPAROUND_BIT_KHR = 0x00000200,
} VkVideoEncodeH264CapabilityFlagBitsKHR;

Description

VK_VIDEO_ENCODE_H264_CAPABILITY_HRD_COMPLIANCE_BIT_KHR specifies whether the implementation may be able to generate HRD compliant bitstreams if any of the nal_hrd_parameters_present_flag or vcl_hrd_parameters_present_flag members of StdVideoH264SpsVuiFlags are set to 1 in the active SPS.
VK_VIDEO_ENCODE_H264_CAPABILITY_PREDICTION_WEIGHT_TABLE_GENERATED_BIT_KHR specifies that if StdVideoH264PpsFlags::weighted_pred_flag is set to 1 or StdVideoH264PictureParameterSet::weighted_bipred_idc is set to STD_VIDEO_H264_WEIGHTED_BIPRED_IDC_EXPLICIT in the active PPS when encoding a P picture or B picture, respectively, then the implementation is able to internally decide syntax for pred_weight_table, as defined in section 7.4.3.2 of the ITU-T H.264 Specification, and the application is not required to provide a weight table in the H.264 slice header parameters.
VK_VIDEO_ENCODE_H264_CAPABILITY_ROW_UNALIGNED_SLICE_BIT_KHR specifies that each slice in a frame with multiple slices may begin or finish at any offset in a macroblock row. If not supported, all slices in the frame must begin at the start of a macroblock row (and hence each slice must finish at the end of a macroblock row). When a picture is encoded with intra refresh, encoding non-rectangular slices also requires: support for the VkVideoEncodeIntraRefreshCapabilitiesKHR::nonRectangularIntraRefreshRegions capability.
VK_VIDEO_ENCODE_H264_CAPABILITY_DIFFERENT_SLICE_TYPE_BIT_KHR specifies that when a frame is encoded with multiple slices, the implementation allows encoding each slice with a different StdVideoEncodeH264SliceHeader::slice_type specified in the H.264 slice header parameters. If not supported, all slices of the frame must be encoded with the same slice_type which corresponds to the picture type of the frame. There is one exception to this rule: if the picture is encoded with the intra refresh mode VK_VIDEO_ENCODE_INTRA_REFRESH_MODE_PER_PICTURE_PARTITION_BIT_KHR, then the currently refreshed slice must specify the slice_type STD_VIDEO_H264_SLICE_TYPE_I and can differ from the slice_type of the other slices regardless of whether VK_VIDEO_ENCODE_H264_CAPABILITY_DIFFERENT_SLICE_TYPE_BIT_KHR is supported.
VK_VIDEO_ENCODE_H264_CAPABILITY_B_FRAME_IN_L0_LIST_BIT_KHR specifies support for using a B frame as L0 reference, as specified in StdVideoEncodeH264ReferenceListsInfo::RefPicList0 in the H.264 picture information.
VK_VIDEO_ENCODE_H264_CAPABILITY_B_FRAME_IN_L1_LIST_BIT_KHR specifies support for using a B frame as L1 reference, as specified in StdVideoEncodeH264ReferenceListsInfo::RefPicList1 in the H.264 picture information.
VK_VIDEO_ENCODE_H264_CAPABILITY_PER_PICTURE_TYPE_MIN_MAX_QP_BIT_KHR specifies support for specifying different QP values in the members of VkVideoEncodeH264QpKHR.
VK_VIDEO_ENCODE_H264_CAPABILITY_PER_SLICE_CONSTANT_QP_BIT_KHR specifies support for specifying different constant QP values for each slice.
VK_VIDEO_ENCODE_H264_CAPABILITY_GENERATE_PREFIX_NALU_BIT_KHR specifies support for generating prefix NAL units by setting VkVideoEncodeH264PictureInfoKHR::generatePrefixNalu to VK_TRUE.
VK_VIDEO_ENCODE_H264_CAPABILITY_MB_QP_DIFF_WRAPAROUND_BIT_KHR indicates support for wraparound during the calculation of the QP values of subsequently encoded macroblocks, as defined in equation 7-37 of the ITU-T H.264 Specification. If not supported, equation 7-37 of the ITU-T H.264 Specification is effectively reduced to the following:

QP_Y = QP_Y,PREV + mb_qp_delta

Note

The effect of this is that the maximum QP difference across subsequent macroblocks is limited to the [-(26 + QpBdOffset_Y / 2), 25 + QpBdOffset_Y / 2] range.
VK_VIDEO_ENCODE_H264_CAPABILITY_B_PICTURE_INTRA_REFRESH_BIT_KHR indicates support for encoding B pictures with intra refresh enabled.

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

SPDX-License-Identifier: CC-BY-4.0

VkVideoEncodeH264CapabilityFlagBitsKHR(3) Manual Page

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