A method of partitioning a coding unit (CU) into one or more transform units (TUs) for encoding a video sequence using at least one processor includes determining a height of the CU; determining a width of the CU; determining a TU size of each of the one or more TUs based on the height of the CU and the width of the CU; determining one or more TU positions of the one or more TUs based on the height of the CU and the width of the CU; and partitioning the CU into the one or more TUs based on the determined size of the one or more TUs and the one or more positions of the one or more TUs.

An encoder includes circuitry and memory. Using the memory, the circuitry, in operation, selects an encoding mode from among candidates including a decoder-side motion vector refinement (DMVR) encoding mode and a partition encoding mode. When the DMVR encoding mode is selected, the circuitry: obtains a first motion vector for a first image block; derives a second motion vector from the first motion vector using motion search; and generates a prediction image for the first image block using the second motion vector. When the partition encoding mode is selected, the circuitry: determines a plurality of partitions in a second image block; obtains a third motion vector for each partition; and generates a prediction image for the second image block using the third motion vector, without deriving a fourth motion vector from the third motion vector using motion search.

Video signal coding and decoding functions can generate lists of potential candidates to use in coding and decoding, for example, predictors. Video signal coding component candidate undergo operations before potential inclusion in candidate lists. The candidates are checked after being modified by the operations to see if other equal candidates are already in the candidate list. If equal candidates are not in the list, the modified candidates are added to the candidate list. If equal candidates are already in the list, the modified candidates are not added to the list. Operations that can be performed comprise rounding and clipping.

The present invention provides a method for encoding a video signal based on an Edge Adaptive Graph-Based Transform (EA-GBT) including detecting a step edge or a ramp edge from a residual signal; generating a graph signal based on at least one of the step edge or the ramp edge; obtaining an EA-GBT coefficient by performing the EA-GBT for the graph signal; quantizing the EA-GBT coefficient; and entropy-encoding the quantized EA-GBT coefficient.

An image decoding method according to the present invention comprises the steps of: deriving a merge candidate of a current block from a neighboring block of the current block; adding the derived merge candidate to a merge candidate list; when the number of merge candidates previously added to the merge candidate list is less than a threshold value, adding at least one prediction area merge candidate included in a prediction area motion information table to the merge candidate list; deriving motion information about the current block on the basis of the merge candidate list; and performing motion compensation on the current block on the basis of the derived motion information.

A video encoding method includes (i) determining a current bit rate of a communication channel between a destination device and a source device that stores an input video frame, and (ii) generating a current reconstructed frame and an encoded bitstream at least in part via inter-frame coding of a current input video frame of a sequence of input video frames using a previously-generated reconstructed frame generated at least in part via inter-frame coding of a previous input video frame. The current reconstructed frame is a compressed version of the current input video frame. When both (i) a subsequent bit rate, determined after said inter-frame coding, is less than a threshold and (ii) the current bit rate exceeds the threshold, the method includes: (a) generating a downscaled reconstructed frame at least in part by downscaling the current reconstructed frame; and (b) appending the encoded bitstream with a bit sequence representing the downscaled reconstructed frame.

A video coder receives data from a bitstream for a block of pixels to be encoded or decoded as a current block of a current picture of a video. Upon determining that an applied block setting of the current block satisfies a threshold condition, the video coder generates a first prediction based on a first motion information for a first prediction unit of the current block. The video coder generates a second prediction based on a second motion information for a second prediction unit of the current block. The video coder generates a third prediction based on the first and second motion information for an overlap prediction region that is defined based on a partitioning between the first prediction unit and the second prediction unit. The video coder encodes or decodes the current block by using the first, second, and third predictions.

An image decoding method according to the present invention can comprise the steps of: acquiring residual coefficients of a current block; dequantizing the residual coefficients; performing secondary inverse transformation on the dequantized residual coefficients; and performing primary inverse transformation on the performance result of the secondary inverse transformation. The secondary inverse transformation can be performed for a partial region of the current block.

A method of encoding a motion information predictor index for an Affine Merge mode, comprising: generating a list of motion information predictor candidates; selecting one of the motion information predictor candidates in the list as an Affine Merge mode predictor; and generating a motion information predictor index for the selected motion information predictor candidate using CABAC coding, one or more bits of the motion information predictor index being bypass CABAC coded.

A decoder includes an entropy decoder configured to derive a number of bins of the binarizations from the data stream using binary entropy decoding by selecting a context among different contexts and updating probability states associated with the different contexts, dependent on previously decoded portions of the data stream; a desymbolizer configured to debinarize the binarizations of the syntax elements to obtain integer values of the syntax elements; a reconstructor configured to reconstruct the video based on the integer values of the syntax elements using a quantization parameter, wherein the entropy decoder is configured to distinguish between 126 probability states and to initialize the probability states associated with the different contexts according to a linear equation of the quantization parameter, wherein the entropy decoder is configured to, for each of the different contexts, derive a slope and an offset of the linear equation from first and second four bit parts of a respective 8 bit initialization value.