The present disclosure relates to an apparatus and a method for providing a plurality of motion vectors related to an image coded in a bitstream, comprising obtaining a set of sample positions within the image, obtaining respective motion vectors associated with the set of sample positions, deriving an additional motion vector based on information coded in the bitstream, determining an additional sample position located within a triangle, which is formed by three sample positions of the set of sample positions, based on the respective motion vectors associated with the three sample positions, the triangle not including any other sample position of the set, adding the additional sample position to the set of sample positions, and associating the derived additional motion vector with the additional sample position. Such method and apparatus provide for an efficient motion flow compression and reconstruction enabling to recover some sample positions without signaling them in the bitstream.

Disclosed herein are a video-decoding method and apparatus and a video encoding method and apparatus, and more particularly a method and an apparatus which perform region-differential image encoding/decoding using a recovered image. In accordance with an encoding method according to an embodiment, a recovered low-quality image is generated by performing encoding on an original image and a recovered high-quality image is generated using the recovered low-quality image. An image is segmented into multiple regions, and encoded reconstruction information for generating a reconstructed high-quality image is generated by performing encoding on the image.

Disclosed herein are a video-decoding method and apparatus and a video encoding method and apparatus, and more particularly a method and an apparatus which perform region-differential image encoding/decoding using a recovered image. In accordance with an encoding method according to an embodiment, a recovered low-quality image is generated by performing encoding on an original image and a recovered high-quality image is generated using the recovered low-quality image. An image is segmented into multiple regions, and encoded reconstruction information for generating a reconstructed high-quality image is generated by performing encoding on the image.

A method and a device for inversely transforming transform coefficients of a current block are disclosed. A method for predicting a current block according to a first mode, includes the steps of: on the basis of a partition mode syntax element, partitioning the current block into non-rectangular blocks; determining an intra-predicted intra block and an inter-predicted inter block among the non-rectangular blocks; and deriving prediction samples of a first area including the inter block on the basis of motion information, and deriving prediction samples of a second area including the intra block on the basis of an intra prediction mode.

An in-loop filtering procedure for improving the picture quality of a reconstructed image (video) can be performed. The in-loop filtering procedure can be also performed on a picture divided into sub pictures. According to embodiments of the present document, sub picture-related information and in-loop filtering-related information can be efficiently signaled.

According to one embodiment of the present document, a (decoded) picture can be split into sub-pictures. Information related to the sub-pictures can be acquired by means of a decoding device, and a decoding procedure can be performed on the basis of the information related to the sub-pictures. In one embodiment, the decoding device can determine, on the basis of the information about the sub-pictures, the location in which information related to locations of virtual boundaries for in-loop filtering is signaled.

An image encoding/decoding method and apparatus are provided. An image decoding method performed by an image decoding apparatus comprises obtaining a current block corresponding to a leaf node of a split tree structure based on a predetermined prediction mode type, resetting a prediction mode type of the current block, obtaining prediction mode information of the current block based on the reset prediction mode type, and generating a prediction block of the current block based on the prediction mode information. The resetting the prediction mode type of the current block may be performed based on at least one of a slice type or size of the current block.

An image encoding/decoding method and apparatus are provided. An image decoding method performed by an image decoding apparatus comprises obtaining a current block corresponding to a leaf node of a split tree structure based on a predetermined prediction mode type, resetting a prediction mode type of the current block, obtaining prediction mode information of the current block based on the reset prediction mode type, and generating a prediction block of the current block based on the prediction mode information. The resetting the prediction mode type of the current block may be performed based on at least one of a slice type or size of the current block.

The inter prediction method comprises: determining a prediction mode parameter of a current block; determining a GPM parameter of the current block in response to that the prediction mode parameter indicates that a GPM is used to determine inter prediction of the current block; determining a first prediction value of a first partition of the current block and a second prediction value of a second partition of the current block; determining a weight index of a sample in the current block based on the GPM parameter of the current block; determining a first weight value and a second weight value of the sample in the current block based on the weight index of the sample in the current block; performing weighted combination of the first prediction value and the second prediction value to obtain the inter prediction of the current block.

The inter prediction method comprises: determining a prediction mode parameter of a current block; determining a GPM parameter of the current block in response to that the prediction mode parameter indicates that a GPM is used to determine inter prediction of the current block; determining a first prediction value of a first partition of the current block and a second prediction value of a second partition of the current block; determining a weight index of a sample in the current block based on the GPM parameter of the current block; determining a first weight value and a second weight value of the sample in the current block based on the weight index of the sample in the current block; performing weighted combination of the first prediction value and the second prediction value to obtain the inter prediction of the current block.