A coding tool is provided to improve the compression performance of inter prediction and is used at the encoder/decoder side to adjust the correction of a motion vector based on a high level syntax. In addition, a method is provided for simply performing an integer sample search step of searching for an integer offset and a fractional sample refinement step of searching for a sub-pixel offset in relation to motion vector refinement among coding tools.

An image encoding/decoding method and apparatus are provided. An image decoding method performed by an image decoding apparatus comprises obtaining inter prediction information of a current block and wraparound information from a bitstream, and generating a prediction block of the current block based on the inter prediction information and the wraparound information. The wraparound information may comprise a first flag specifying whether wraparound motion compensation is enabled for a current picture including the current block. Based on the first flag having a predetermined value specifying that the wraparound motion compensation is enabled for the current picture, the prediction block may be generated by performing the wraparound motion compensation, and the wraparound motion compensation may be performed based on either boundaries of a current subpicture including the current block or boundaries of a reference picture of the current block, based on whether the current subpicture is independently coded or not.

An image encoding/decoding method and apparatus are provided. An image decoding method performed by an image decoding apparatus comprises obtaining inter prediction information of a current block and wraparound information from a bitstream, and generating a prediction block of the current block based on the inter prediction information and the wraparound information. The wraparound information may comprise a first flag specifying whether wraparound motion compensation is enabled for a current picture including the current block. Based on the first flag having a predetermined value specifying that the wraparound motion compensation is enabled for the current picture, the prediction block may be generated by performing the wraparound motion compensation, and the wraparound motion compensation may be performed based on either boundaries of a current subpicture including the current block or boundaries of a reference picture of the current block, based on whether the current subpicture is independently coded or not.

The present disclosure provides an image encoder. The image encoder is configured to encode an original image and reduce compression loss. The image encoder comprises an image signal processor and a compressor. The image signal processor is configured to receive a first frame image and a second frame image and generates a compressed image of the second frame image using a boundary pixel image of the first frame image. The image signal processor may include memory configured to store first reference pixel data which is the first frame image. The compressor is configured to receive the first reference pixel data from the memory and generate a bitstream obtained by encoding the second frame image based on a difference value between the first reference pixel data and the second frame image. The image signal processor generates a compressed image of the second frame image using the bitstream generated by the compressor.

Disclosed are methods and apparatuses for image data encoding/decoding. A method for decoding a 360-degree image includes the steps of: receiving a bitstream obtained by encoding a 360-degree image; generating a prediction image by making reference to syntax information obtained from the received bitstream; adding the generated prediction image to a residual image obtained by dequantizing and inverse-transforming the bitstream, so as to obtain a decoded image; and reconstructing the decoded image into a 360-degree image according to a projection format. Therefore, the performance of image data compression can be improved.

A method comprising: encoding an input picture into a coded picture; reconstructing picture corresponding to the coded picture; encoding a spatial region into a coded tile, the encoding comprising: determining a horizontal offset and a vertical offset indicative of a region-wise anchor position of the spatial region within the decoded picture; encoding the horizontal offset and the vertical offset; determining that a prediction unit at position of a first horizontal coordinate and a first vertical coordinate is predicted relative to the region-wise anchor position; indicating that the prediction unit is predicted relative to a prediction-unit anchor position; deriving a prediction-unit anchor position equal to sum of the first horizontal coordinate and the horizontal offset, and the first vertical coordinate and the vertical offset, respectively; and determining a motion vector for the prediction unit; and applying the motion vector relative to the prediction-unit anchor position to obtain a prediction block.

Method and apparatus of Inter prediction for video coding are disclosed. When a sub-block motion compensation coding tool is selected for the current block, the method generates sub-block MVs (motion vectors) associated with multiple sub-blocks, which are included or contained in the current block, according to the sub-block motion compensation coding tool, constrains the sub-block MVs within a range to form constrained sub-block MVs, and applies motion compensation to the current block using the constrained sub-block MVs or applies motion compensation to the current block using one sub-block MV within the range around the primary MV in a second list if a corresponding sub-block MV in a first list is outside the range. In another method, motion compensation is applied to the current block only using reference pixels of reference sub-blocks within a primary reference block.

Disclosed are methods and apparatuses for decoding an image. A method includes receiving a bitstream obtained by encoding the image; dividing a first coding block into a plurality of second coding blocks; generating a prediction block of a second coding block based on syntax information obtained from the bitstream; and reconstructing the second coding block based on the prediction block and a residual block of the second coding block, the residual block being obtained by performing a dequantization and an inverse-transform on quantized transform coefficients from the bitstream. The first coding block has a recursive division structure. The first coding block is divided based on at least one of a quad tree division, a binary tree division or a triple tree division.

The present disclosure provides methods for picture processing. The method can include: receiving a bitstream comprising a set of pictures; determining, according to the received bitstream, whether a virtual boundary is signaled at a sequence level for the set of pictures; in response to the virtual boundary being signaled at the sequence level, determining a position of the virtual boundary for the set of pictures, the position being bounded by a range signaled in the received bitstream; and disabling in-loop filtering operations across the virtual boundary.

Disclosed is a method and apparatus for encoding/decoding a video. According to an embodiment, provided is a method of setting a level for each of one or more regions, including decoding a definition syntax element related to level definition and a designation syntax element related to target designation from a bitstream; defining one or more levels based on the definition syntax element; and setting a target level designated by the designation syntax element among the defined levels for a target region designated by the designation syntax element.