Devices and methods of intra prediction of a block of a picture are provided. In various embodiments, information indicating an Intra Sub-Partitions (ISP) split type can be obtained. A value of a filter flag can be set based on the ISP split type. For instance, the value of the filter flag can be set to 0 when the ISP split type does not indicate not to split a current block. A set of coefficients of an interpolation filter can then be selected according to the value of the filter flag. For instance, fG coefficients or fC coefficients can be selected based on the value of the filter flag. Still in those embodiment, the selected set of coefficients can be applied to reference samples. In some embodiments, the method removes mode dependency during selection of interpolation filter type. This could increase encoding or decoding efficiency.

Devices and methods of intra prediction of a block of a picture are provided. In various embodiments, information indicating an Intra Sub-Partitions (ISP) split type can be obtained. A value of a filter flag can be set based on the ISP split type. For instance, the value of the filter flag can be set to 0 when the ISP split type does not indicate not to split a current block. A set of coefficients of an interpolation filter can then be selected according to the value of the filter flag. For instance, fG coefficients or fC coefficients can be selected based on the value of the filter flag. Still in those embodiment, the selected set of coefficients can be applied to reference samples. In some embodiments, the method removes mode dependency during selection of interpolation filter type. This could increase encoding or decoding efficiency.

A method and decoding unit for decoding a compressed data structure that encodes a set of Haar coefficients for a 2×2 quad of pixels of a block of pixels. The set of Haar coefficients comprises a plurality of differential coefficients and an average coefficient. A first portion of the compressed data structure encodes the differential coefficients for the 2×2 quad of pixels. A second portion of the compressed data structure encodes the average coefficient for the 2×2 quad of pixels. The first portion of the compressed data structure is used to determine signs and exponents differential coefficients which are non-zero. The second portion of the compressed data structure is used to determine a representation of the average coefficient. The result of a weighted sum of the differential coefficients and the average coefficient for the 2×2 quad of pixels is determined using: (i) the determined signs and exponents for the differential coefficients which are non-zero, (ii) the determined representation of the average coefficient, and (iii) respective weights for the differential coefficients. The determined result is used to determine the decoded value. The determined decoded value is outputted.

A picture may be divided into sub-pictures/slices/tiles. For example, the picture may be divided into sub-picture(s), and subpicture-related information may be used for coding. The sub-picture-related information may be generated by an encoding device and transmitted to a decoding device. According to embodiments of the present document, sub-picture-related information can be efficiently signaled.

A picture may be divided into sub-pictures/slices/tiles. For example, the picture may be divided into sub-picture(s), and subpicture-related information may be used for coding. The sub-picture-related information may be generated by an encoding device and transmitted to a decoding device. According to embodiments of the present document, sub-picture-related information can be efficiently signaled.

The invention relates to a method and a device for decoding an image by means of a partition unit comprising an additional region. The method of decoding an image by means of a partition unit comprising an additional region comprises the steps of: partitioning, by reference to a syntax element acquired from a received bit stream, an encoded image, which is included in the bitstream, in at least one partition unit; define an additional region for at least one partition unit; and decoding the encoded image based on the partition unit for which the additional region is defined. The invention improves the image coding efficiency.

The invention relates to a method and a device for decoding an image by means of a partition unit comprising an additional region. The method of decoding an image by means of a partition unit comprising an additional region comprises the steps of: partitioning, by reference to a syntax element acquired from a received bit stream, an encoded image, which is included in the bitstream, in at least one partition unit; define an additional region for at least one partition unit; and decoding the encoded image based on the partition unit for which the additional region is defined. The invention improves the image coding efficiency.

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.