Abstract: Described are video coding systems comprising a post-processing stage using position dependent intra prediction combination where a predicted sample is modified based on a weighting between a value of a left or top reference sample and the obtained predicted value for the sample, wherein the left or top reference sample is determined based on the intra prediction angle. This provides better computing efficiency while keeping identical compression performance. Encoding method, decoding method, encoding apparatus and decoding apparatus based on this post-processing stage are proposed.

Abstract: Decoding or encoding picture information can involve determining a value associated with a prediction of a pixel of a block of picture information, wherein, the prediction is based on an intra-prediction along a non-diagonal direction, determining, from among a plurality of decoded pixels neighboring the block on the top and the left, at least four reference samples for the block based on the non-diagonal direction, and wherein the determining of the value comprises an interpolation based on a quadratic model and the four reference samples; and decoding or encoding at least a portion of the picture information based on the value.

Abstract: A video encoder or decoder processes portions of video using intra coding and with variable block shapes. Under the general aspects, intra prediction directions are adapted to the block shape or aspect ratio. The general aspects described adaptively replace several conventional angular intra prediction modes with wide-angle intra prediction modes for non-square blocks. The total number of angular directions for any block can remain the same as in prior video coding standards or can be reduced or expanded. To keep the same number of prediction directions, directions along a shorter rectangular edge of a target block are removed but replaced with addition directions along the longer edge of the rectangular target block. For directions with wide angles, reference sample smoothing is performed. Signaling can be provided to inform a corresponding decoder regarding the prediction modes and directions.

Abstract: Flexible methods to use a combination of coding modes while keeping good performance tradeoff are implemented with embodiments that determine coding mode information. In one embodiment, determination is made of activation of a first coding mode, and upon determination of whether a second coding mode is used, coding or decoding using the determined modes occurs. Other embodiments enable use of multiple reference lines, intra sub-block partitioning, matrix intra prediction, and low frequency non-separable transforms.

Abstract: A video encoder or decoder processes portions of video using intra coding and with variable block shapes. Under the general aspects, intra prediction directions are adapted to the block shape or aspect ratio. The general aspects described adaptively replace several conventional angular intra prediction modes with wide-angle intra prediction modes for non-square blocks. The total number of angular directions for any block can remain the same as in prior video coding standards or can be reduced or expanded. To keep the same number of prediction directions, directions along a shorter rectangular edge of a target block are removed but replaced with addition directions along the longer edge of the rectangular target block. For directions with wide angles, reference sample smoothing is performed. Signaling can be provided to inform a corresponding decoder regarding the prediction modes and directions.

Abstract: Decoding or encoding picture information can involve determining a value associated with a prediction of a pixel of a block of picture information, wherein, the prediction is based on an intra-prediction along a non-diagonal direction, determining, from among a plurality of decoded pixels neighboring the block on the top and the left, at least four reference samples for the block based on the non-diagonal direction, and wherein the determining of the value comprises an interpolation based on a quadratic model and the four reference samples; and decoding or encoding at least a portion of the picture information based on the value.

Abstract: To encode a coding unit in the inter modes, there exist multiple inter modes that signal the motion information using a Motion Vector Predictor (MW) list. The MW lists for different coding modes include spatial predictors. In one embodiment, for all coding modes that use MVP lists, the top spatial predictor is first added to the motion vector predictor list before the left spatial predictor. In another embodiment, a subset of coding modes adds the top spatial predictor before the left spatial predictor, and another subset of coding modes adds the left spatial predictor before the top spatial predictor. For example, all merge modes add the top spatial predictor first, and all AMVP modes add the left spatial predictor first. In another example, all non-sub-block modes add the top spatial predictor first, and all sub-block modes add the left spatial predictor first.

Abstract: A method of performing intra prediction for encoding or decoding uses multiple layers of reference samples. The layers are formed into reference arrays that are used by a function, such as a weighted combination, to form a final prediction. The prediction is used in encoding or decoding a block of video data. The weights can be determined in a number of ways, and for a given prediction mode, the same weights, or different weights can be used for all pixels in a target block. If the weights are varied, they can depend on the distance of the target pixel from reference arrays.

Abstract: A method and apparatus for performing prediction for encoding or decoding uses intra prediction with sub-partitions. The sub-partitions are oriented either horizontally or vertically and can use wide-angle modes different than that of the video block they originate from. Reference samples for a sub-partition are those of the video block when reference samples for the sub-partition are not available, such as due to direction. In an embodiment, when a sub-partition is square, conventional intra prediction directions are used. Reference samples can be used from a block above and right of the video block or left and below the video block using a mapping along a prediction direction, vertically, or horizontally.

Abstract: A method and apparatus for performing intra prediction for encoding or decoding adds multiple prediction modes to those of prior intra prediction schemes. A horizontal mode, a vertical mode, and a diagonal mode are added. Reference pixels for each of the added modes can come from multiple pixel positions away from a block to be encoded or decoded. Reference pixels to the left and above a block are reconstructed from those already coded. Reference pixels from right of, and below, a block are estimated or extrapolated and can be based on other pixels around the block. An index can be sent in a bitstream indicating which prediction was used.

Abstract: Methods and apparatus for using wide-angle intra prediction for rectangular blocks enable greater prediction angles. Wide-angle intra prediction enables intra prediction direction angles beyond the conventional 45 and ?135 degrees. In one embodiment, when a video block to be coded or decoded is non-square, additional intra prediction directions are enabled in the direction of the longer block edge and more reference samples are available along that edge. An index is used to indicate the prediction direction and can be adapted according to the additional intra predictions in the longer direction, with correspondingly fewer prediction directions along the shorter block edge. This preserves the number of prediction modes that need to be indexed but allows their angles to correspond to the shape of the block.

Abstract: An improvement in coding efficiency is achieved through restrictions on successive divisions of asymmetric splitting in advanced video coding algorithms, which frequently rely on splitting of a block of video data prior to coding using several transform sizes. Successive divisions of asymmetric splitting are forbidden if an equivalent split can be attained using triple splitting. In an embodiment, a video block is split using successive splits, but the second type of split is dependent on the first type of split.

Abstract: A method and apparatus for performing intra prediction mode partitioning predicts pixels of a video coding block using a plurality of intra prediction modes over a plurality of regions of the video coding block. Predictions can be based on reference arrays using at least one reference line above the block to be coded and/or using at least one reference column to the left of the block to be coded. Different prediction modes are used in different regions of the coding block. In at least one embodiment, the video coding block is split into a plurality of partitions in addition to having a plurality of intra prediction modes over different regions of the block. Signaling enables a decoder to determine the number of regions within a coding block. In at least another embodiment, prediction modes allowable within regions of a video coding block differ by one angular position.

Abstract: Methods and apparatus for performing intra prediction in an encoder or a decoder for non-square blocks enable a combination of reference samples from a row above the non-square block and a row to the left of the non-square block to be used for the prediction. In one embodiment, a weighted combination of reference samples are used. In another embodiment, the angles of prediction are extended in the longer direction of the non-square block, such that less angles of prediction are used in the shorter direction.

Abstract: The disclosure relates to a method for encoding image data, the method including intra-predicting, or predicting by combining inter-prediction and intra-prediction, a first block of the image data by using an intra-prediction mode using a first single transformation obtained by taking account of the first block size. The disclosure also relates to a method for encoding image data, a variable coding length being used for signaling a plurality of Prediction Modes by the encoding, the method comprising:—intra-predicting a first block of the image data by using an intra-prediction mode using a first transformation, the first transformation being obtained by taking account of the first block size, —encoding information signaling a use of the intra-prediction mode in a bitstream, the information being encoded as one of the plurality of Prediction Modes. The disclosure further relates to the corresponding decoding methods, devices and media.

Abstract: A method and apparatus for performing prediction for encoding or decoding uses intra prediction with sub-partitions. The sub-partitions are oriented either horizontally or vertically and can use wide-angle modes different than that of the video block they originate from. Reference samples for a sub-partition are those of the video block when reference samples for the sub-partition are not available, such as due to direction. In an embodiment, when a sub-partition is square, conventional intra prediction directions are used. Reference samples can be used from a block above and right of the video block or left and below the video block using a mapping along a prediction direction, vertically, or horizontally.

Abstract: Described are video coding systems comprising a post-processing stage using position dependent intra prediction combination where a predicted sample is modified based on a weighting between a value of a left or top reference sample and the obtained predicted value for the sample, wherein the left or top reference sample is determined based on the intra prediction angle. This provides better computing efficiency while keeping identical compression performance. Encoding method, decoding method, encoding apparatus and decoding apparatus based on this post-processing stage are proposed.

Abstract: Methods and apparatus for performing intra prediction in an encoder or a decoder for non-square blocks enable a combination of reference samples from a row above the non-square block and a row to the left of the non-square block to be used for the prediction. In one embodiment, a weighted combination of reference samples are used. In another embodiment, the angles of prediction are extended in the longer direction of the non-square block, such that less angles of prediction are used in the shorter direction.

Abstract: A video coding system comprises a post-processing stage using position dependent intra prediction combination where a predicted sample is modified based on a weighting between a value of a left or top reference sample and the obtained predicted value for the sample, wherein the left or top reference sample is determined based on the intra prediction angle. This provides better computing efficiency while keeping identical compression performance. Encoding method, decoding method, encoding apparatus and decoding apparatus based on this post-processing stage are proposed.

Abstract: A method and apparatus for performing intra prediction for encoding or decoding adds multiple prediction modes to those of prior intra prediction schemes. A horizontal mode, a vertical mode, and a diagonal mode are added. Reference pixels for each of the added modes can come from multiple pixel positions away from a block to be encoded or decoded. Reference pixels to the left and above a block are reconstructed from those already coded. Reference pixels from right of, and below, a block are estimated or extrapolated and can be based on other pixels around the block. An index can be sent in a bitstream indicating which prediction was used.