An image decoding apparatus obtain pieces of coded data that is included in a bitstream and generated by coding tiles. Tile boundary independence information is further obtained from the bitstream, with the tile boundary independence information indicating whether each of boundaries between the tiles is one of a first boundary or a second boundary. The pieces of coded data are decoded to generate image data of the tiles. Image data of a first tile is generated by decoding a first code string included in first coded data with reference to decoding information of a decoded tile when the tile boundary independence information indicates the first boundary, and by decoding the first code string without referring to the decoding information of the decoded tile when the tile boundary independence information indicates the second boundary.

An image decoding apparatus obtain pieces of coded data that is included in a bitstream and generated by coding tiles. Tile boundary independence information is further obtained from the bitstream, with the tile boundary independence information indicating whether each of boundaries between the tiles is one of a first boundary or a second boundary. The pieces of coded data are decoded to generate image data of the tiles. Image data of a first tile is generated by decoding a first code string included in first coded data with reference to decoding information of a decoded tile when the tile boundary independence information indicates the first boundary, and by decoding the first code string without referring to the decoding information of the decoded tile when the tile boundary independence information indicates the second boundary.

A video decoding method performed by a decoding apparatus includes deriving one of a plurality of cross-component linear model (CCLM) prediction mode as a CCLM prediction mode of the current chroma block, deriving a sample number of neighboring chroma samples of the current chroma block based on the CCLM prediction mode of the current chroma block, a size of the current chroma block, and a specific value derived as 2. The method includes deriving the neighboring chroma samples of the sample number, calculating CCLM parameters based on the neighboring chroma samples and the down sampled neighboring luma samples, deriving prediction samples for the current chroma block based on the CCLM parameters and the down sampled luma samples and generating reconstructed samples for the current chroma block based on the prediction samples.

Disclosed is an image data encoding/decoding method and apparatus. A method for decoding a 360-degree image comprises 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; combining the generated prediction image with 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.

Disclosed is an image data encoding/decoding method and apparatus. A method for decoding a 360-degree image comprises 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; combining the generated prediction image with 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.

An image encoding device and a method, and an image decoding device and a method that are designed to improve encoding efficiency in IntraBC. A screen is divided into four slices (Slices #0 through #3). In a case where reference to a different slice is prohibited, the range that can be referred to from the current CTU in Slice #2 is only the decoded portion in Slice #2, and therefore, any block in Slice #1 cannot be referred to, for example. In the case of the present technology, on the other hand, decoded different slices (Slice #0 and Slice #1)are included in the referable range, and accordingly, a block in Slice #1 can be referred to from the current CTU in Slice #2.

An image decoding method according to the present document is characterized by including: a step for receiving a bitstream including residual information; a step for deriving transform coefficients for a target block on the basis of the residual information; a step for deriving corrected transform coefficients on the basis of an inverse non-separable transform of the transform coefficients; and a step for deriving residual samples for the target block on the basis of an inverse primary transform of the corrected transform coefficients, wherein the inverse non-separable transform is performed when the size of the target block is equal to or smaller than the size of a prescribed maximum transform application block.

A video coding mechanism is disclosed. The mechanism includes partitioning a picture into a plurality of tiles. A number of the tiles are included in a tile group. The mechanism determines whether the tile group is a raster scan tile group or a rectangular tile group. The number of tiles in the tile group is determined based on whether the tile group is the raster scan tile group or the rectangular tile group. The tiles are encoded into a bitstream based on the tile group. The bitstream is stored for communication toward a decoder.

A video coding mechanism is disclosed. The mechanism includes partitioning a picture into a plurality of tiles. A number of the tiles are included in a tile group. The mechanism determines whether the tile group is a raster scan tile group or a rectangular tile group. The number of tiles in the tile group is determined based on whether the tile group is the raster scan tile group or the rectangular tile group. The tiles are encoded into a bitstream based on the tile group. The bitstream is stored for communication toward a decoder.

Several systems, methods and integrated circuits capable of reducing blocking artifacts in video data are disclosed. In an embodiment, a system for reducing blocking artifacts in video data includes a processing module and a deblocking module. The deblocking module comprises a luma deblocking filter and a chroma deblocking filter configured to filter an edge between adjacent blocks associated with the video data, where a block of the adjacent blocks corresponds to one of a prediction block and a transform block. The processing module is communicatively associated with the deblocking module and is operable to configure at least one filter coefficient corresponding to the chroma deblocking filter based on one or more filter coefficients corresponding to the luma deblocking filter. The processing module is further configured to cause the chroma deblocking filter to filter the edge between the adjacent blocks based on the configured at least one filter coefficient.