Method and device for filtering image in image coding system
AssigneeLG Electronics Inc.
InventorsJunghak Nam, Jaehyun Lim
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Abstract
A filtering method by a decoding device according to the present invention comprises the steps of: receiving information relating to ALF control depth; deciding an ALF control unit on the basis of information relating to the division depth and the ALF control depth of a current block in a restoration picture with respect to a current picture; determining whether or not ALF is applied to the current block in an ALF control unit level; and, if the ALF is determined to be applied to the current block, performing the ALF for the current block. In the filtering method, the current picture is recursively divided on the basis of a QTBT structure, and the current block is one of blocks divided on the basis of the QTBT structure.
Claims13
A picture filtering method of a decoding apparatus, the picture filtering method comprising:
- receiving information about an adaptive loop filtering (ALF) control depth;
- determining an ALF control unit based on information about a split depth of a current block, within a reconstructed picture for a current picture, and the ALF control depth;
- determining whether ALF is applied to the current block at the ALF control unit level;
- and
- performing the ALF for the current block, when it is determined that the ALF is to be applied to the current block,
- wherein the current picture is recursively split based on a quad-tree binary-tree (QTBT) structure, and the current block is one of blocks which are split based on the QTBT structure,
- wherein the split depth of the current block represents the sum of a QT split depth and a BT split depth of the current block, and
- wherein the ALF control unit is determined based on the following equation,
- AlfControlDepth=min(alf_control_depth,current_QT_depth+current_BT_depth)
- where the alf_control_depth represents the ALF control depth, the current_QT_depth represents the QT split depth of the current block, the current_BT_depth represents the BT split depth of the current block, and the AlfControlDepth represents the ALF control unit.
A decoding apparatus which performs picture filtering, the decoding apparatus comprising:
- an entropy decoder which receives information about an ALF control depth;
- and
- a filter which determines an ALF control unit based on information about a split depth of a current block, within a reconstructed picture for a current picture, and the ALF control depth, determines whether an ALF is applied to the current block at the ALF control unit level, and performs the ALF for the current block, when it is determined that the ALF is to be applied to the current block,
- wherein the current picture is recursively split based on a QTBT structure, and the current block is one of blocks which are split based on the QTBT structure,
- wherein the split depth of the current block represents the sum of a QT split depth and a BT split depth of the current block, and
- wherein the ALF control unit is determined based on the following equation,
- AlfControlDepth=min(alf_control_depth,current_QT_depth+current_BT_depth)
- where the alf_control_depth represents the ALF control depth, the current_QT_depth represents the QT split depth of the current block, the current_BT_depth represents the BT split depth of the current block, and the AlfControlDepth represents the ALF control unit.
A picture filtering information encoding method of an encoding apparatus, the picture filtering information encoding method comprising:
- determining an ALF control depth;
- generating information about the determined ALF control depth;
- determining an ALF control unit comprising a current block;
- generating ALF flag information about the ALF control unit;
- and
- encoding the information about the ALF control depth and the ALF flag information,
- wherein the current block is one of blocks in which a current picture is recursively split based on a QTBT structure,
- wherein a split depth of the current block represents the sum of a QT split depth and a BT split depth of the current block, and
- wherein the ALF control unit is determined based on the following equation,
- AlfControlDepth=min(alf_control_depth,current_QT_depth+current_BT_depth)
- where the alf_control_depth represents the ALF control depth, the current_QT_depth represents the QT split depth of the current block, the current_BT_depth represents the BT split depth of the current block, and the AlfControlDepth represents the ALF control unit.
Dependencies are inferred from the claim text.