Method and apparatus for video signal processing using sub-block based motion compensation
A video signal processing method and apparatus for encoding or decoding a video signal is disclosed. More particularly, a video signal processing method and a video signal processing apparatus using the same are disclosed, wherein a method for processing a video signal comprises the steps of: obtaining a set of control point motion vectors for prediction of a current block; obtaining the motion vector of each sub-block of the current block using control point motion vectors of the set of control point motion vectors; obtaining a predictor of the each sub-block of the current block using the motion vectors of the each sub-block; obtaining a predictor of the current block by combining predictors of the each sub-block; and restoring the current block using the predictor of the current block.
1. A non-transitory computer-readable medium storing a bitstream, the bitstream being decoded by a decoding method,
wherein the decoding method, comprising:
obtaining an indicator for selecting a control point motion vector set from among control point motion vector set candidates,
wherein the control point motion vector set candidates include a first control point motion vector set, a second control point motion vector set, and a third control point motion vector set,
wherein the first control point motion vector set includes a first control point motion vector, a second control point motion vector, and a third control point motion vector,
wherein the second control point motion vector set includes the first control point motion vector, the second control point motion vector, and a fourth control point motion vector,
wherein the third control point motion vector set includes the first control point motion vector and a fifth control point motion vector,
wherein the first control point motion vector corresponds to an upper left corner of a current block,
wherein the second control point motion vector corresponds to an upper right corner of the current block,
wherein the third control point motion vector corresponds to a lower left corner of the current block,
wherein the fourth control point motion vector is determined based on the first control point motion vector and the second control point motion vector,
wherein the fifth control point motion vector is determined based on the first control point motion vector and the third control point motion vector,
wherein the fourth control point motion vector and the fifth control point motion vector are respectively included in different control point motion vector sets;
obtaining a motion vector of each subblock of the current block based on control point motion vectors of the control point motion vector set indicated by the indicator,
wherein the indicator is used to obtain location information of one or more neighboring blocks referenced to derive the motion vector of each subblock of the current block among one or more neighboring blocks of the current block; and
reconstructing the current block based on the motion vector of each subblock of the current block.
2. The non-transitory computer-readable medium storing the bitstream of claim 1 ,
wherein the reconstructing the current block based on the motion vector is comprising:
obtaining a predictor of each subblock of the current block based on the motion vector of each subblock of the current block;
obtaining a predictor of the current block by combining the predictor of each subblock of the current block;
reconstructing the current block based on the predictor of the current block.
3. A apparatus for decoding a video signal, the device comprising
a processer,
wherein the processer is configured to:
obtain an indicator for selecting a control point motion vector set among control point motion vector set candidates,
wherein the control point motion vector set candidates include a first control point motion vector set, a second control point motion vector set, and a third control point motion vector set,
wherein the first control point motion vector set includes a first control point motion vector, a second control point motion vector, and a third control point motion vector,
wherein the second control point motion vector set includes the first control point motion vector, the second control point motion vector, and a fourth control point motion vector,
wherein the third control point motion vector set includes the first control point motion vector and a fifth control point motion vector,
wherein the first control point motion vector corresponds to an upper left corner of a current block,
wherein the second control point motion vector corresponds to an upper right corner of the current block,
wherein the third control point motion vector corresponds to a lower left corner of the current block,
wherein the fourth control point motion vector is determined based on the first control point motion vector and the second control point motion vector,
wherein the fifth control point motion vector is determined based on the first control point motion vector and the third control point motion vector,
wherein the fourth control point motion vector and the fifth control point motion vector are respectively included in different control point motion vector sets,
obtain a motion vector of each subblock of the current block based on control point motion vectors of the control point motion vector set indicated by the indicator,
wherein the indicator is used to obtain location information of one or more neighboring blocks referenced to derive the motion vector of each subblock of the current block among one or more neighboring blocks of the current block; and
reconstruct the current block based on the motion vector of each subblock of the current block.
4. The apparatus of claim 3 ,
wherein the processor is configured to:
obtain a predictor of each subblock of the current block based on the motion vector of each subblock of the current block;
obtain a predictor of the current block by combining the predictor of each subblock of the current block;
reconstruct the current block based on the predictor of the current block.
5. A apparatus for encoding a video signal, the device comprising
a processor,
wherein the processor is configured to
obtain a bitstream to be decoded by a decoder using a decoding method,
wherein the decoding method comprising:
obtaining an indicator for selecting a control point motion vector set from among control point motion vector set candidates,
wherein the control point motion vector set candidates include a first control point motion vector set, a second control point motion vector set, and a third control point motion vector set,
wherein the first control point motion vector set includes a first control point motion vector, and a second control point motion vector, and a third control point motion vector,
wherein the second control point motion vector set includes the first control point motion vector, the second control point motion vector and a fourth control point motion vector,
wherein the third control point motion vector set includes the first control point motion vector, and a fifth control point motion vector,
wherein the first control point motion vector corresponds to an upper left corner of a current block,
wherein the second control point motion vector corresponds to an upper right corner of the current block,
wherein the third control point motion vector corresponds to a lower left corner of the current block,
wherein the fourth control point motion vector is determined based on the first control point motion vector and the second control point motion vector,
wherein the fifth control point motion vector is determined based on the first control point motion vector and the third control point motion vector,
wherein the fourth control point motion vector and the fifth control point motion vector are respectively included in different control point motion vector sets;
obtaining a motion vector of each subblock of the current block based on control point motion vectors of the control point motion vector set indicated by the indicator,
wherein the indicator is used to obtain location information of one or more neighboring blocks referenced to derive the motion vector of each subblock of the current block among one or more neighboring blocks of the current block; and
reconstructing the current block based on the motion vector of each subblock of the current block.
6. The apparatus of claim 5 ,
wherein the reconstructing the current block based on the motion vector is comprising:
obtaining a predictor of each subblock of the current block based on the motion vector of each subblock of the current block;
obtaining a predictor of the current block by combining the predictor of each subblock of the current block;
reconstructing the current block based on the predictor of the current block.