In a method and a device for encoding or decoding an image according to the present invention, motion information for bidirectional prediction of a current block may be derived on the basis of an inter mode previously defined in the device for encoding or decoding an image, and inter prediction may be performed on the current block on the basis of the motion information, wherein the motion information for bidirectional prediction is adjusted to be motion information for unidirectional prediction according to the predefined inter mode.

In some aspects, the disclosure is directed to methods and systems for reducing memory utilization and increasing efficiency during affine merge mode for versatile video coding by utilizing motion vectors stored in a motion data line buffer for a prediction unit of a second coding tree unit neighboring a first coding tree unit to derive control point motion vectors for the first coding tree unit.

In some aspects, the disclosure is directed to methods and systems for reducing memory utilization and increasing efficiency during affine merge mode for versatile video coding by utilizing motion vectors stored in a motion data line buffer for a prediction unit of a second coding tree unit neighboring a first coding tree unit to derive control point motion vectors for the first coding tree unit.

Image encoding and decoding methods and devices thereof are provided. The encoding method includes: performing downsampling on a first image to obtain a second image; encoding the second image to obtain a second image bit stream, and sending the second image bit stream to a decoding end; processing the second image to obtain a third image having a resolution the same as that of the first image; calculating a difference between the third image and the first image to obtain a first difference image; regulating pixel values of the first difference image to fall within a pre-set range, to obtain a second difference image; and encoding the second difference image to obtain a second difference image bit stream, and sending the second difference image bit stream to the decoding end to enable the decoding end to reconstruct the first image.

Image encoding and decoding methods and devices thereof are provided. The encoding method includes: performing downsampling on a first image to obtain a second image; encoding the second image to obtain a second image bit stream, and sending the second image bit stream to a decoding end; processing the second image to obtain a third image having a resolution the same as that of the first image; calculating a difference between the third image and the first image to obtain a first difference image; regulating pixel values of the first difference image to fall within a pre-set range, to obtain a second difference image; and encoding the second difference image to obtain a second difference image bit stream, and sending the second difference image bit stream to the decoding end to enable the decoding end to reconstruct the first image.

A method for encoding a video signal includes estimating a space requirement for encoding a tile of a video frame, writing a first value in a first value space of the bitstream, wherein the first value describes a size of a second value space, and defining the second value space in the bitstream, wherein the size of the second value space is based on an estimated space requirement. The method also includes writing encoded content in a content space of the bitstream, determining a size of the content space subsequent to writing encoded content in the content space, and writing a second value in the second value space of the bitstream, wherein the second value describes the size of the content space.

A video encoder or decoder processes portions of video using virtual temporal affine motion candidates. Under the general aspects, virtual temporal affine candidates are created using only the classical temporal motion buffer information, avoiding the storage of additional affine parameters in a temporal motion buffer. A motion field for encoding or decoding a video block is generated based on the virtual temporal affine candidates. In one embodiment, collocated motion candidates are rescaled by adjusting the picture order count of the determined motion field. In another embodiment, resolution adaptation is performed to enable a current motion buffer to correspond to a reference motion buffer.

Methods, apparatuses, and non-transitory computer-readable mediums are provided. A block vector of a current block that is to be coded in intra block copy (IBC) mode is determined. The block vector points to a first reference block of the current block in a current picture. An operation is performed on at least one component of the block vector based on the first reference block being outside a search range of the current block. The block vector is modified by the operation to point to a second reference block that is within the search range for the current block. The current block is encoded based on the modified block vector. The performing the operation includes performing a modulo operation on a y component of the block vector based on a size of a current coding tree unit (CTU) that includes the current block.

A method of dividing an input image signal into pixel blocks, and performing inter-prediction on the divided pixel blocks. This method includes selecting predicted motion information from a motion information buffer storing motion information in an encoded region, and predicting motion information of an encoding target block by using the predicted motion information. The method further includes acquiring representative motion information from a plurality of items of motion information in an encoded region in accordance with first information indicating a method of selecting the predicted motion information, thereby obtaining only the representative motion information.

A method for intra prediction comprises determining a first MPM candidate corresponding to a left-side candidate block on the basis of a position of the left-side candidate block adjacent to a left side of a current block; determining a second MPM candidate corresponding to an upper-end candidate block on the basis of a position of the upper-end candidate block adjacent to an upper end of the current block; generating an MPM candidate list including a plurality of MPM candidates, on the basis of the first MPM candidate and the second MPM candidate; and determining one MPM candidate of the plurality of the MPM candidates that constitute the MPM candidate list as an intra prediction mode of the current block, and performing intra prediction for the current block on the basis of the determined intra prediction mode to generate a prediction block corresponding to the current block.