Abstract: A method for determining a prediction block for decoding or encoding a current block in a current picture of a video stream. The method includes obtaining a pair of initial motion vectors comprising a first and a second initial motion vector. The method also includes determining whether to refine the initial motion vectors. The step of determining whether or not to refine the initial motion vectors comprises: i) determining whether a first prediction scheme and/or a second prediction scheme is enabled and ii) determining to refrain from refining the initial motion vectors as a result of determining that either the first prediction scheme or second prediction scheme is enabled or determining to refine the initial motion vectors as a result of determining neither the first prediction scheme nor second prediction scheme is enabled.

Abstract: A method and decoder for determining that a decoder conforming to a first profile is capable of decoding a first picture of a video bitstream conforming to a second profile is provided. The method includes obtaining an indicator value, the indicator value indicating conformance to a profile. The method includes determining whether the first picture in the video bitstream is a still picture. The method includes responsive to the indicator value indicating conformance to the second profile and the first picture is determined to be a still picture, determining that the decoder conforming to the first profile is capable of decoding the first picture of the video bitstream.

Abstract: Methods, decoders, and programs are provided. All blocks of an image that has been encoded are decoded. At least one sample of at least one block of the image is filtered by, for each block being filtered: for each sample being filtered: selecting a plurality of neighboring samples. For at least one neighboring sample, a difference is calculated between the neighboring sample and the sample. A modifier value is obtained. A modifier sum is derived based on a sum of the modifier values for the neighboring samples. A correction value is determined based on a conditional addition of at least one shifted version of the modifier sum, each shift having a same number of shift steps in each correction value determination. A filtered sample is derived based on the sample and correction value. The filtered sample is stored. The block and filtered sample is output towards a decoder output.

Abstract: Methods, decoders, and programs are provided. All blocks of an image that has been encoded are decoded. At least one sample of at least one block of the image is filtered by, for each block being filtered: for each sample being filtered: selecting a plurality of neighboring samples. For at least one neighboring sample, a difference is calculated between the neighboring sample and the sample. A modifier value is obtained. A modifier sum is derived based on a sum of the modifier values for the neighboring samples. A correction value is determined based on a conditional addition of at least one shifted version of the modifier sum, each shift having a same number of shift steps in each correction value determination. A filtered sample is derived based on the sample and correction value. The filtered sample is stored. The block and filtered sample is output towards a decoder output.

Abstract: A method for determining a prediction block for decoding or encoding a current block in a current picture of a video stream. The method includes obtaining a pair of initial motion vectors, the pair of initial motion vectors comprising a first initial motion vector and a second initial motion vector. The method also includes determining whether or not to refine the initial motion vectors. The method further includes refining the initial motion vectors as a result of determining to refine the initial motion vectors.

Abstract: A method, decoder, and apparatus are provided. Responsive to a current block being a MIP predicted block, it is determined whether it has one or multiple transform blocks. A MIP weight matrix to be used to decode the current block is determined based on a MIP prediction mode. Responsive to the MIP predicted block having one transform block, the MIP predicted block is derived based on the MIP weight matrix and previously decoded elements in the bitstream. Responsive to the MIP predicted block having multiple transform blocks: deriving a first MIP predicted block is derived based on the MIP weight matrix and previously decoded elements in the bitstream and remaining MIP predicted blocks are derived based further on decoded elements in at least one decoded transform block of the current block. The MIP predicted block(s) are output for subsequent processing.

Abstract: Methods and devices for determining video picture resolution. A first source picture is obtained and a first reduced resolution picture is generated based on the first source picture. A first similarity metric is determined for the first reduced resolution picture and the first source picture. A picture resolution is selected based at least in part on the first similarity metric.

Abstract: A deblocking method for deblocking a boundary between a first block of samples, block P, and a second block of samples, block Q. The method includes determining whether at least one of the P block or the Q block is a combined intra-inter prediction block; and, as a result of determining that at least one of the P block or the Q block is a combined intra-inter prediction block, deblocking the boundary between the P block and the Q block.

Abstract: There is provided a method of encoding a picture. The method comprises selecting a motion vector. MV, for a current block within the picture. The method comprises determining whether a condition is satisfied, wherein determining whether the condition is satisfied comprises: (i) determining if a subblock-based motion refinement is applicable for the current block and (ii) determining if a first subblock within the current block satisfies a criteria. The method comprises, as a result of determining that the condition is satisfied, not using the selected MV for encoding the current block.

Abstract: There are provided mechanisms for temporal motion vector prediction of a current picture in a series of pictures of a video sequence. The method comprises determining, for a current block of the current picture, whether any one of: left, top, top-right and left-bottom spatial neighboring blocks of the current block in the current picture uses a collocated picture as a reference picture. The method further comprises, when the determination is that one of the left, top, top-right and left-bottom spatial neighboring block uses a collocated picture as a reference picture, using a motion vector of the one of the spatial neighboring blocks as a temporal vector of the current block.

Abstract: A prediction unit for an encoder or decoder implements matrix based intra prediction. Input boundary samples for a current block are downsampled to obtain reduced boundary samples for matrix multiplication and/or linear interpolation, or both. In one embodiment, downsampling is performed in a manner that aligns the reduced boundary samples with an output of a matrix multiplication unit of the prediction unit. In other embodiments, downsampling is performed without averaging. The embodiments reduce the complexity of the prediction unit and the latency of the encoder or decoder.

Abstract: A method for decoding a current block in a current picture of a video bitstream includes decoding, from the video bitstream, a first motion vector for the current block relative to a first reference block of a first reference picture having a first picture order count, and decoding, from the video bitstream, a second motion vector for the current block relative to a second reference block of a second reference picture having a second picture order count. A similarity metric is generated based on a comparison of the first motion vector and the second motion vector. The method further includes determining whether to refine the first motion vector based on the similarity metric, generating a first refined motion vector from the first motion vector, and performing motion compensation to derive a first reference block from the first reference picture using the first refined motion vector.

Abstract: Methods and apparatus for encoding or decoding a first structure within a picture in a video sequence are provided. The method comprises, for a second structure within the first structure, determining an initial motion vector, MV, and MV candidates. The method comprises, for each of the MV candidates, using the MV candidate to derive first and second reference blocks, and a size of the first and second reference blocks may not be equal to a size of the second structure. The method comprises deriving a cost value based on samples from the first and second reference blocks. The method comprises using the cost values from the MV candidates to derive a best MV candidate and using the best MV candidate to derive prediction samples for the second structure.

Abstract: A process for selecting a transform set for a prediction block. The process can be used in both an encoder and a decoder. For example, the process can be used in both an encoder and a decoder for a prediction block that has been predicted from a reference block. In some embodiments, both the prediction block and the reference block are intra blocks.

Abstract: A method for deblocking at least one boundary of a coding unit, wherein the boundary forms a first side and a second side of the coding unit, wherein a video picture comprises the coding unit, and wherein the first and second sides use a same reference picture. The method includes obtaining a first motion vector component in the first side; obtaining a second motion vector component in the second side; determining whether an absolute difference between the first motion vector component and the second motion vector component is equal to or larger than a predetermined threshold that is less than 1 sample; and as a result of determining that the absolute difference between the first motion vector component and the second motion vector component is equal to or larger than the predetermined threshold, applying deblocking to the vertical or horizontal boundary between the first side and the second side.

Abstract: A method of performing bi-directional optical flow, BDOF, processing for a video sequence of images, with each image including a plurality of blocks with bidirectional-predicted inter coding blocks, BPICBs. The method includes obtaining a shifted pair of refinement parameters per a subblock of a bidirectional-predicted inter coding block, wherein the shifted pair of refinement parameters includes a shifted first refinement parameter and a shifted second refinement parameter.

Abstract: There are provided mechanisms for temporal motion vector prediction of a current picture in a series of pictures of a video sequence. The method comprises determining, for a current block of the current picture, whether any one of: left, top, top-right and left-bottom spatial neighboring blocks of the current block in the current picture uses a collocated picture as a reference picture. The method further comprises, when the determination is that one of the left, top, top-right and left-bottom spatial neighboring block uses a collocated picture as a reference picture, using a motion vector of the one of the spatial neighboring blocks as a temporal vector of the current block.

Abstract: The present embodiments introduce a new type of random access point in video bitstreams that can be used for random access operations but can be represented in encoded form at a lower bit-cost as compared to IRAP pictures. The random access point is a dependent random access point (DRAP) picture that is encoded and decoded using an IRAP picture and/or a previous, according to a decoding order, DRAP picture as sole reference picture(s) for the DRAP picture. The DRAP picture is encoded as a trailing picture that may be used for reference and constitutes a random access point in a video bitstream.

Abstract: A decoder can be configured to obtain a current inter block and a plurality of previously decoded inter blocks. Each inter block of the plurality of inter blocks can include a motion vector having a resolution. The decoder generates a list of motion vector predictor candidates that is used to predict the motion vector that is associated with the current inter block. Generating the list of motion vector predictor candidates can include defining a set of inter blocks that includes a number of previously decoded inter blocks; scanning the inter blocks in the set of inter blocks in a scanning order; and for each of the inter blocks in the set of inter blocks: deriving a motion vector prediction candidate using the motion vector of the inter block; and determining whether a criterion is satisfied.

Abstract: A prediction unit (60) for an encoder (24) or decoder (44) implements matrix based intra prediction Input boundary samples for a current block are downsampled to obtain reduced boundary samples for matrix multiplication and/or linear interpolation, or both. In one embodiment, downsampling is performed in a manner that aligns the reduced boundary samples with an output of a matrix multiplication unit of the prediction unit. In other embodiments, downsampling is performed without averaging. The embodiments reduce the complexity of the prediction unit and the latency of the encoder (24) or decoder (44).