Abstract: A method for decoding a block of a picture includes decoding, from a data stream, an intra-coding mode for the block, deriving a predictor for a prediction partition of the block using at least one already reconstructed samples neighboring the prediction partition and the intra-coding mode, deriving a prediction residual for each of the at least two transform partitions included in the prediction partition, and combining the predictor of the prediction partition and the prediction residual for each of the at least two transform partitions included in the prediction partition to reconstruct the prediction partition. The block is partitioned into multiple transform partitions based on a partition dimension flag, and the prediction partition includes at least two transform partitions of the multiple transform partitions.

Abstract: Apparatus configured to derive a set-selective syntax element indicating whether the predetermined block is to be predicted using one of a first set of intra-prediction modes comprising a DC intra prediction mode and angular prediction modes. If the set-selective syntax element indicates that the predetermined block is to be predicted using one of the first set of intra-prediction modes, the apparatus is configured to use a list of most probable intra-prediction modes. If the set-selective syntax element indicates that the predetermined block is not to be predicted using one of the first set of intra-prediction modes, the apparatus is configured to use a matrix-based intra-prediction mode. The list of most probable intra-prediction modes is formed such that the list of most probable intra-prediction modes is free of the DC intra prediction mode in case of the neighbouring blocks being predicted by any of the angular intra prediction modes.

Abstract: Apparatus for decoding a predetermined block (18) of a picture using intra-prediction, configured to read, from the data stream (12), a mode index (200), the mode index pointing to one out of a list (204) of matrix-based intra-prediction modes. Additionally, the apparatus is configured to predict samples (108) of the predetermined block (18) by computing a matrix-vector product (206) between an input vector (102) derived from reference samples (17) in a neighborhood of the predetermined block (18) and a prediction matrix (19) associated with the matrix-based intra-prediction mode (k) pointed to by the mode index (200) and associating components (210) of an output vector (208) obtained by the matrix vector product (206) onto sample positions (104) of the predetermined block.

Abstract: Decoder for decoding a transformed representation of a sample block from a data stream. If a first coded coefficient is located inside a predetermined subarea of the transform coefficient block and if the underlying transform is within a first set of available transforms, the decoder decodes coefficients along a first coefficient scan order. If the transform is within a second set of In available transforms, the decoder decodes coefficients located within the predetermined subarea along a second coefficient scan order, and infers that coefficients located outside the predetermined subarea are zero. The first coefficient scan order is so that coefficients outside the predetermined subarea are scanned between two transform coefficients located inside the predetermined subarea. The second coefficient scan order does not scan any coefficient outside the predetermined subarea between scanning the coefficients within the predetermined subarea.

Abstract: A method, computer program, and apparatus for decoding a predetermined block of a picture using intra-prediction by reading, for each of predetermined intra-prediction blocks, from a data stream, a mode index identifying a matrix-based intra-prediction mode. Samples of each predetermined intra-prediction block are predicted by computing a matrix-vector product between an input vector derived from reference samples and a prediction matrix associated with the identified matrix-based intra-prediction mode (k) and associating components of an output vector obtained by the matrix-vector product onto sample positions of the predetermined block. Further predetermined intra-predicted blocks of the picture are predicted to obtain a prediction signal. A transformation flag is decoded from the data stream using context adaptive binary arithmetic coding, and a prediction residual is decoded and re-transformed using a reverse transformation based on the transformation flag to obtain a prediction residual signal.

Abstract: Coding efficiency increases are achieved by using composed prediction signals to predict a predetermined block of a picture.

Abstract: A better compromise between encoding complexity and achievable rate distortion ratio, and/or to achieve a better rate distortion ratio is achieved by using multitree sub-divisioning not only in order to subdivide a continuous area, namely the sample array, into leaf regions, but using the intermediate regions also to share coding parameters among the corresponding collocated leaf blocks. By this measure, coding procedures performed in tiles—leaf regions—locally, may be associated with coding parameters individually without having to, however, explicitly transmit the whole coding parameters for each leaf region separately. Rather, similarities may effectively exploited by using the multitree subdivision.

Abstract: An encoder for hybrid video coding, the encoder for providing an encoded representation of a video sequence on the basis of an input video content, and the encoder configured to: determine one or more syntax elements related to a portion of the video sequence; select a processing scheme to be applied to the portion of the video sequence based a property described by on the one or more syntax elements, the processing scheme for acquiring a sample for a motion-compensated prediction at an integer and/or fractional location within the portion of the video sequence; encode an index indicating the selected processing scheme such that a given encoded index value represents different processing schemes depending on the property described by the one or more syntax elements; and provide, as the encoded representation of the video sequence, a bit stream including the one or more syntax elements and the encoded index.

Abstract: Information available from coding/decoding the base layer, i.e. base-layer hints, is exploited to render the motion-compensated prediction of the enhancement layer more efficient by more efficiently coding the enhancement layer motion parameters.

Abstract: Decoder for decoding a picture from a data stream, configured to check whether a plurality of coding parameters, which are contained in the data stream, relate to a predetermined portion of the picture and control a prediction residual transform mode and a quantization accuracy with respect to the predetermined portion, are indicative of a coding parameter setting corresponding to a lossless prediction residual coding. Responsive to the plurality of coding parameters being indicative of the coding parameter setting corresponding to the lossless prediction residual coding, the decoder is configured to set one or more predetermined coding options relating to one or more tools of the decoder for processing a prediction residual corrected predictive reconstruction with respect to the predetermined portion so that the one or more tools are disabled with respect to the predetermined portion.

Abstract: A decoder for block-based decoding of picture data of a picture is configured to decode a current block of the picture by determining first and second sets of luma in a neighborhood of the current block, the first set of luma samples having smaller luma values than the second set of luma samples, fitting a straight-line having a linear function through first and second pairs of luma-chroma samples, wherein the first and second pairs of luma-chroma samples are determined based on the first and second sets of luma samples, respectively, and on first and second corresponding chroma samples, respectively, in said neighborhood of the current block, and predicting chroma samples of the current block using luma samples of the current block and said linear function. The present invention further concerns a respective encoder and corresponding methods for encoding and decoding.

Abstract: A picture in a data stream is subdivided into different size transform bocks. For a transform block, a transformation is selected by checking whether the block's size exceeds a threshold. If it does, a default technique is used to select the transformation. If it does not, a transformation is used from a list of transformations as identified by an index, the list including an identity transformation and non-identity transformations. A coefficients block in the data stream is decoded, and if the selected transformation is the identity transformation, then the coefficients block is used as a residual sample array, and if the selected transformation is not the identity transformation, the coefficients block is subjected to an inverse transformation corresponding to the selected transformation to obtain a residual sample array used to correct a prediction for the transform block.

Abstract: A raw byte sequence payload describing a picture in slices, WPP substreams or tiles and coded using context-adaptive binary arithmetic coding is subdivided into tranches with continuing the context-adaptive binary arithmetic coding probability adaptation across tranche boundaries. Thereby, tranche boundaries additionally introduced within slices, WPP substreams or tiles do not lead to a reduction in the entropy coding efficiency of these entities. However, the tranches are smaller than the original slices, WPP substreams or tiles and accordingly they may be transmitted earlier, i.e. with lower delay, than the un-chopped original entities. According to another aspect combinable with the first aspect, substream marker NAL units are used within a sequence of NAL units of a video bitstream to enable a transport demultiplexer to assign data of slices within NAL units to the corresponding substreams or tiles so as to be able to, in parallel, serve a multi-threaded decoder with the corresponding substreams or tiles.

Abstract: An apparatus includes an encoder, which receives image or video data, encodes the data and provides a bitstream representing the data. The encoder includes a CABAC encoder, which receives a binary valued syntax element associated with a block of the data to be encoded, and encodes, using a selected context model, the syntax element into coded bits for the bitstream. The syntax element includes a tool flag indicating whether or not certain coding tool, like linear weighted intra prediction, is employed when encoding a block of the data. For a block of the data which exhibits an aspect ratio larger than 2 and for a block of the data which exhibits an aspect ratio less than or equal to 2, and to which blocks the certain coding tool is applicable, first and second context models for encoding the tool flag are selected from a group of one or more first and second context models, respectively.

Abstract: Concepts are described, including encoding of a video into data stream and decoding of a data stream having a video encoded thereinto, using motion compensation prediction between pictures of equal resolution and pictures of different resolution, based on motion vectors at a half-sample resolution and on motion vectors at a different resolution using interpolation filters to obtain sub-sample values within a reference sample array. The interpolation filter is selected from two interpolation filter versions different in a higher edge preserving property, and the selection is depending on whether a current picture is equal in picture resolution to the reference sample array in horizontal and/or vertical dimension, and/or a constraint information in the data stream.

Abstract: A favorable merging or grouping of simply connected regions into which the array of information samples is sub-divided, is coded with a reduced amount of data. To this end, a predetermined relative locational relationship is defined enabling an identifying, for a predetermined simply connected region, of simply connected regions within the plurality of simply connected regions which have the predetermined relative locational relationship to the predetermined simply connected region. Namely, if the number is zero, a merge indicator for the predetermined simply connected region may be absent within the data stream. In other embodiments, spatial sub-division is performed depending on a first subset of syntax elements, followed by combining spatially neighboring simply connected regions depending on a second subset of syntax elements, to obtain an intermediate sub-division.

Abstract: A video decoder for decoding a video from a data stream is configured to decode an indication from the data stream which is valid for a sequence of pictures of the video, and indicates that RASL pictures within the sequence of pictures are coded in a manner excluding a predetermined set of one or more coding tools.

Abstract: The handling of scalable data streams by network entities is rendered less complex by, in the data stream, accompanying packets which actually carry data by packets of a different packet type which have a scalability axes descriptor defining the number of scalability axes and a semantic meaning thereof. In another aspect, the handling of scalable data streams by network entities is rendered more efficient by conveying level and/or profile descriptors using packets other than the data carrying packets, with profile and/or level descriptors being divided up into a first set explicitly signaling the definition of the available coding option set and/or available syntax element value range for a respective operation point, and a second set of profile and/or level descriptors which signal the definition of the available coding option set and/or available syntax element value range for their respective operation points by reference another profile and/or level descriptor.

Abstract: Block-based coding of a picture is rendered more effective by providing an intra-prediction coding concept according to which a certain block of the picture is intra-prediction coded using a certain intra-coding mode by partitioning the predetermined block into partitions along a certain dimension with the number of partitions being greater than two and/or the partitions being one sample wide along the certain dimension with the partitions being, for reconstruction purposes, sequentially subject to spatial prediction using the intra-prediction coding mode signaled for the certain block followed by correcting the thus obtained predictor using a prediction residual so that for preceding partitions a reconstruction of the samples is available to the decoder at the time of processing the next, then current, partition. Signaling overhead with respect to the partitioning may be left off or may be kept low.

Abstract: Arithmetic encoder for encoding a plurality of symbols is configured to derive an interval size information for an arithmetic encoding of one or more symbol values to be encoded on the basis of one or more state variable value, in a first mode of operation, and to update the one or more state variable values and/or the interval size information for an encoding of one or more subsequent symbol values to be encoded in the first mode; in a second mode, the arithmetic encoder is configured to disable an update of the one or more state variable values and/or of the interval size information. Additionally, further embodiments of arithmetic encoders and decoders and video encoders and decoders are described.