Systems and methods are described for reducing the complexity of using bi-directional optical flow (BIO) in video coding. In some embodiments, bit-width reduction steps are introduced in the BIO motion refinement process to reduce the maximum bit-width used for BIO calculations. In some embodiments, simplified interpolation filters are used to generate predicted samples in an extended region around a current coding unit. In some embodiments, different interpolation filters are used for vertical versus horizontal interpolation. In some embodiments, BIO is disabled for coding units with small heights and/or for coding units that are predicted using a sub-block level inter prediction technique, such as advanced temporal motion vector prediction (ATMVP) or affine prediction.

Systems and methods are described for reducing the complexity of using bi-directional optical flow (BIO) in video coding. In some embodiments, bit-width reduction steps are introduced in the BIO motion refinement process to reduce the maximum bit-width used for BIO calculations. In some embodiments, simplified interpolation filters are used to generate predicted samples in an extended region around a current coding unit. In some embodiments, different interpolation filters are used for vertical versus horizontal interpolation. In some embodiments, BIO is disabled for coding units with small heights and/or for coding units that are predicted using a sub-block level inter prediction technique, such as advanced temporal motion vector prediction (ATMVP) or affine prediction.

Flag information associated with the current block is obtained in coded information, which indicates whether the current block is intra predicted based at least in part on an intra mode derivation. In response to the flag information being true, a plurality of candidate intra modes is determined based on neighboring samples of the current block. A first intra mode of the current block is determined based on a first syntax element that is included in the coded information. The first syntax element indicates the first intra mode of the current block from a most probable mode (MPM) list and a MPM remainder. A second intra mode of the current block is determined based on the first intra mode and the plurality of candidate intra modes. The current block is reconstructed based on the first intra mode and the second intra mode.

Flag information associated with the current block is obtained in coded information, which indicates whether the current block is intra predicted based at least in part on an intra mode derivation. In response to the flag information being true, a plurality of candidate intra modes is determined based on neighboring samples of the current block. A first intra mode of the current block is determined based on a first syntax element that is included in the coded information. The first syntax element indicates the first intra mode of the current block from a most probable mode (MPM) list and a MPM remainder. A second intra mode of the current block is determined based on the first intra mode and the plurality of candidate intra modes. The current block is reconstructed based on the first intra mode and the second intra mode.

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 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.

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.

A method for intra-prediction of a current block includes selecting peripheral pixels of the current block, where the peripheral pixels are used to generate a prediction block for the current block; for each prediction pixel of the prediction block, performing steps including selecting two respective pixels of the peripheral pixels; and calculating the prediction pixel by interpolating at least the two respective pixels; and coding a residual block corresponding to a difference between the current block and the prediction block.

A method for intra-prediction of a current block includes selecting peripheral pixels of the current block, where the peripheral pixels are used to generate a prediction block for the current block; for each prediction pixel of the prediction block, performing steps including selecting two respective pixels of the peripheral pixels; and calculating the prediction pixel by interpolating at least the two respective pixels; and coding a residual block corresponding to a difference between the current block and the prediction block.