A method for intra prediction of a video block, comprising: padding of luminance reference samples rows for a chroma component of a current block vertically aligned with a largest coding unit (LCU) boundary; applying a filter F to reconstructed luma samples of a luma component of the current block and to luma samples in selected position neighboring to the current block, to obtain filtered reconstructed luma samples, wherein a shape of the F is same for blocks in the LCU; obtaining linear model coefficients, based on the filtered reconstructed luma samples; and performing cross-component prediction based on the obtained linear model coefficients and the filtered reconstructed luma samples of the current block, to obtain a prediction value of the chroma component of the current block.

A method for decoding a data stream representative of an image split into blocks. For a current block of the image, an item of information indicating a coding mode among a first and a second coding mode of the current block is decoded from the data stream and the current block is decoded depending on this information. When the coding mode of the current block corresponds to the second coding mode, the current block is reconstructed from a prediction obtained, for each pixel, from another previously decoded pixel belonging to the current block or to a previously decoded block of the image, and from a decoded residue associated with the pixel. At least one processing method is applied to the reconstructed current block for at least one pixel of the current block depending on the coding mode of the current block and/or the coding mode of the neighbouring blocks.

A method for decoding a data stream representative of an image split into blocks. For a current block of the image, an item of information indicating a coding mode among a first and a second coding mode of the current block is decoded from the data stream and the current block is decoded depending on this information. When the coding mode of the current block corresponds to the second coding mode, the current block is reconstructed from a prediction obtained, for each pixel, from another previously decoded pixel belonging to the current block or to a previously decoded block of the image, and from a decoded residue associated with the pixel. At least one processing method is applied to the reconstructed current block for at least one pixel of the current block depending on the coding mode of the current block and/or the coding mode of the neighbouring blocks.

Described is picture segmentation through columns and slices in video encoding and decoding. A video picture is divided into a plurality of columns, each column covering only a part of the video picture in a horizontal dimension. All coded tree blocks (“CTBs”) belonging to a slice may belong to one or more columns. The columns may be used to break the same or different prediction or in-loop filtering mechanisms of the video coding, and the CTB scan order used for encoding and/or decoding may be local to a column. Column widths may be indicated in a parameter set and/or may be adjusted at the slice level. At the decoder, column width may be parsed from the bitstream, and slice decoding may occur in one or more columns.

Described is picture segmentation through columns and slices in video encoding and decoding. A video picture is divided into a plurality of columns, each column covering only a part of the video picture in a horizontal dimension. All coded tree blocks (“CTBs”) belonging to a slice may belong to one or more columns. The columns may be used to break the same or different prediction or in-loop filtering mechanisms of the video coding, and the CTB scan order used for encoding and/or decoding may be local to a column. Column widths may be indicated in a parameter set and/or may be adjusted at the slice level. At the decoder, column width may be parsed from the bitstream, and slice decoding may occur in one or more columns.

According to an embodiment of the present document, a method for increasing the accuracy of in-loop filtering is proposed. In an example, the filtering accuracy of chroma blocks can be improved on the basis of luma blocks by performing a cross component adaptive loop filtering process.

According to an embodiment of the present document, a method for increasing the accuracy of in-loop filtering is proposed. In an example, the filtering accuracy of chroma blocks can be improved on the basis of luma blocks by performing a cross component adaptive loop filtering process.

Certain aspects of the present disclosure provide techniques for encoding image data for one or more images. In one embodiment, a method includes the steps of downscaling the one or more images, and encoding the one or more downscaled images using an image codec. Another embodiment concerns a computer-implemented method of decoding encoded image data, and a computer-implemented method of encoding and decoding image data.

Certain aspects of the present disclosure provide techniques for encoding image data for one or more images. In one embodiment, a method includes the steps of downscaling the one or more images, and encoding the one or more downscaled images using an image codec. Another embodiment concerns a computer-implemented method of decoding encoded image data, and a computer-implemented method of encoding and decoding image data.

Methods and apparatus for video processing are disclosed. The processing may include video encoding, video decoding, or video transcoding. One example method includes performing a conversion between a video including a picture including one or more slices and a bitstream of the video. The conversion conforms to a rule that specifies that whether a deblocking filter is applied to the one or more slices referring to a picture parameter set is based at least on a first syntax element included in the picture parameter set. The first syntax element indicates whether the deblocking filter is disabled for the picture.