C Specification

Bits which may be set in VkVideoEncodeH264CapabilitiesEXT::flags, indicating the supported H.264 encoding capabilities, are:

// Provided by VK_EXT_video_encode_h264
typedef enum VkVideoEncodeH264CapabilityFlagBitsEXT {
    VK_VIDEO_ENCODE_H264_CAPABILITY_HRD_COMPLIANCE_BIT_EXT = 0x00000001,
    VK_VIDEO_ENCODE_H264_CAPABILITY_PREDICTION_WEIGHT_TABLE_GENERATED_BIT_EXT = 0x00000002,
    VK_VIDEO_ENCODE_H264_CAPABILITY_ROW_UNALIGNED_SLICE_BIT_EXT = 0x00000004,
    VK_VIDEO_ENCODE_H264_CAPABILITY_DIFFERENT_SLICE_TYPE_BIT_EXT = 0x00000008,
    VK_VIDEO_ENCODE_H264_CAPABILITY_B_FRAME_IN_L0_LIST_BIT_EXT = 0x00000010,
    VK_VIDEO_ENCODE_H264_CAPABILITY_B_FRAME_IN_L1_LIST_BIT_EXT = 0x00000020,
    VK_VIDEO_ENCODE_H264_CAPABILITY_PER_PICTURE_TYPE_MIN_MAX_QP_BIT_EXT = 0x00000040,
    VK_VIDEO_ENCODE_H264_CAPABILITY_PER_SLICE_CONSTANT_QP_BIT_EXT = 0x00000080,
    VK_VIDEO_ENCODE_H264_CAPABILITY_GENERATE_PREFIX_NALU_BIT_EXT = 0x00000100,
} VkVideoEncodeH264CapabilityFlagBitsEXT;

Description

  • VK_VIDEO_ENCODE_H264_CAPABILITY_HRD_COMPLIANCE_BIT_EXT indicates if the implementation guarantees generating a HRD compliant bitstream if nal_hrd_parameters_present_flag or vcl_hrd_parameters_present_flag are enabled in StdVideoH264SpsVuiFlags.

  • VK_VIDEO_ENCODE_H264_CAPABILITY_PREDICTION_WEIGHT_TABLE_GENERATED_BIT_EXT indicates that when weighted_pred_flag is enabled or STD_VIDEO_H264_WEIGHTED_BIPRED_IDC_EXPLICIT from StdVideoH264WeightedBipredIdc is used, the implementation is able to internally decide syntax for pred_weight_table.

  • VK_VIDEO_ENCODE_H264_CAPABILITY_ROW_UNALIGNED_SLICE_BIT_EXT indicates 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).

  • VK_VIDEO_ENCODE_H264_CAPABILITY_DIFFERENT_SLICE_TYPE_BIT_EXT indicates that when a frame is encoded with multiple slices, the implementation allows encoding each slice with a different StdVideoEncodeH264SliceHeader::slice_type. 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. For example, all slices of a P-frame would be encoded as P-slices.

  • VK_VIDEO_ENCODE_H264_CAPABILITY_B_FRAME_IN_L0_LIST_BIT_EXT indicates support for using a B frame as L0 reference.

  • VK_VIDEO_ENCODE_H264_CAPABILITY_B_FRAME_IN_L1_LIST_BIT_EXT indicates support for using a B frame as L1 reference.

  • VK_VIDEO_ENCODE_H264_CAPABILITY_PER_PICTURE_TYPE_MIN_MAX_QP_BIT_EXT indicates support for specifying different QP values in the members of VkVideoEncodeH264QpEXT.

  • VK_VIDEO_ENCODE_H264_CAPABILITY_PER_SLICE_CONSTANT_QP_BIT_EXT indicates support for specifying different constant QP values for each slice.

  • VK_VIDEO_ENCODE_H264_CAPABILITY_GENERATE_PREFIX_NALU_BIT_EXT indicates support for generating prefix NALUs by setting VkVideoEncodeH264PictureInfoEXT::generatePrefixNalu to VK_TRUE.

See Also

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 2014-2023 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0