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D3D12DDI_VIDEO_ENCODER_PICTURE_CONTROL_CODEC_DATA_H264_REFERENCE_PICTURE_MARKING_OPERATION_0082_0 structure (d3d12umddi.h)

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The D3D12DDI_VIDEO_ENCODER_PICTURE_CONTROL_CODEC_DATA_H264_REFERENCE_PICTURE_MARKING_OPERATION_0082_0 structure describes changes in the reference pictures as memory operations as a tuple of an operation identifier and associated parameters needed for the operation.

Syntax

typedef struct D3D12DDI_VIDEO_ENCODER_PICTURE_CONTROL_CODEC_DATA_H264_REFERENCE_PICTURE_MARKING_OPERATION_0082_0 {
  UCHAR memory_management_control_operation;
  UINT  difference_of_pic_nums_minus1;
  UINT  long_term_pic_num;
  UINT  long_term_frame_idx;
  UINT  max_long_term_frame_idx_plus1;
} D3D12DDI_VIDEO_ENCODER_PICTURE_CONTROL_CODEC_DATA_H264_REFERENCE_PICTURE_MARKING_OPERATION_0082_0;

Members

memory_management_control_operation

The control operation to be applied to affect the reference picture marking state. Valid operation values follow.

Value Description
0 End memory_management_control_operation syntax element loop.
1 Mark a short-term reference picture as "unused for reference".
2 Mark a long-term reference picture as "unused for reference".
3 Mark a short-term reference picture as "used for long-term reference" and assign a long-term frame index to it.
4 Specify the maximum long-term frame index and mark all long-term reference pictures having long-term frame indices greater than the maximum value as "unused for reference".
5 Mark all reference pictures as "unused for reference" and set the MaxLongTermFrameIdx variable to "no long-term frame indices".
6 Mark the current picture as "used for long-term reference" and assign a long-term frame index to it.

difference_of_pic_nums_minus1

This member is used with memory_management_control_operation equal to 3 or 1 to assign a long-term frame index to a short-term reference picture or to mark a short-term reference picture as "unused for reference". When the associated memory_management_control_operation is processed by the decoding process, the resulting picture number derived from difference_of_pic_nums_minus1 shall be a picture number assigned to one of the reference pictures marked as "used for reference" and not previously assigned to a long-term frame index.

long_term_pic_num

This member is used with memory_management_control_operation equal to 2 to mark a long-term reference picture as "unused for reference". When the associated memory_management_control_operation is processed by the decoding process, long_term_pic_num shall be equal to a long-term picture number assigned to one of the reference pictures that is currently marked as "used for long-term reference".

long_term_frame_idx

This member is used with memory_management_control_operation equal to 3 or 6 to assign a long-term frame index to a picture. When the associated memory_management_control_operation is processed by the decoding process, the value of long_term_frame_idx shall be in the range of 0 to MaxLongTermFrameIdx, inclusive.

max_long_term_frame_idx_plus1

The value minus 1 specifies the maximum value of long-term frame index allowed for long-term reference pictures (until receipt of another value of max_long_term_frame_idx_plus1). The value of max_long_term_frame_idx_plus1 shall be in the range of 0 to max_num_ref_frames, inclusive.

Remarks

The variable MaxLongTermFrameIdx is derived as follows:

  • If max_long_term_frame_idx_plus1 is equal to 0, MaxLongTermFrameIdx is set equal to "no long-term frame indices".
  • If max_long_term_frame_idx_plus1 is greater than 0, MaxLongTermFrameIdx is set equal to max_long_term_frame_idx_plus1 − 1.

The operation of marking the current frame as a short-term reference is given by a flag present in the D3D12DDI_VIDEO_ENCODER_PICTURE_CONTROL_CODEC_DATA_H264_FLAGS_0080 structure with its corresponding PictureOrderCountNumber and FrameDecodingOrderNumber values indicated in the associated picture control structure.

The variable max_num_ref_frames is indicated by the maximum decoded picture buffer (DPB) capacity reported.

Note that for marking an instantaneous decoder refresh (IDR) frame as long-term reference, the proposed explicit mechanism is to mark it as short term reference first, by setting D3D12DDI_VIDEO_ENCODER_PICTURE_CONTROL_FLAG_0080_USED_AS_REFERENCE_PICTURE when calling EncodeFrame for the IDR frame, and later promoting it to be a long-term reference frame using memory management operation '3' to mark a short-term reference picture as "used for long-term reference" and assign a long-term frame index to it.

Alternatively, if encoding an IDR frame and setting adaptive_ref_pic_marking_mode_flag = 1, the driver assumes that the client is attempting to set the H264 slice header long_term_reference_flag and will do so in the output bitstream for the EncodeFrame call.

For more details about the picture marking process, see the H.264 specification, section 8.2.5.4 "Adaptive memory control decoded reference picture marking process".

See D3D12 video encoding for general information.

Requirements

Requirement Value
Minimum supported client Windows 11 (WDDM 3.0)
Header d3d12umddi.h

See also

D3D12DDI_VIDEO_ENCODER_PICTURE_CONTROL_CODEC_DATA_H264_0082_0

PFND3D12DDI_VIDEO_ENCODE_FRAME_0082_0