Telefonaktiebolaget Lm Ericsson (publ)

Ruoyang Yu

Rickard Sjöberg

Jacob Ström

Kenneth Andersson

Zhi Zhang

Martin Pettersson

Du Liu

Jonatan Samuelsson

Per Wennersten

Jack Enhorn

Mitra Damghanian

Davood Saffar

Lukasz Litwic

Rickard Sjoberg

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.

Selective subblock-based motion refinement

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.

Deblocking using sub-PEL motion vector threshold

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.

Transform selection in a video encoder and/or video decoder

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. The method includes determining a BDOF offset without performing any right shifting using at least the shifted pair of refinement parameters by, for each sample in each subblock within each bidirectional-predicted inter coding block, determining the BDOF offset using the shifted first refinement parameter, the shifted second refinement parameter, a first horizontal gradient block and a first vertical gradient block for a first prediction block, and a second horizontal gradient block and a second vertical gradient block for a second prediction block.

Methods of video encoding and/or decoding with bidirectional optical flow simplification on shift operations and related apparatus

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.

Simplified downsampling for matrix based intra prediction

There is provided a method for processing a bitstream. The method comprises determining a value, N, wherein N identifies a number of ordered layer representations, wherein N is greater than or equal to 3 such that the N ordered layer representations comprises a highest layer representation, a second highest layer representation, and a third highest layer representation. The method further comprises determining a value for the highest layer representation. The method comprises, after determining the value for the highest layer representation and before determining a value for the third highest layer representation, determining a value for the second highest layer representation. The method comprises, after determining the value for the second highest layer representation, determining a value for the third highest layer representation.

Derivation of a value for each layer representation of a bitstream

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.

Side motion refinement in video encoding/decoding systems

A method for decoding a picture comprising a virtual boundary from a coded video bitstream. The method includes determining one or more of a maximum picture width or a maximum picture height from one or more syntax elements S1 in the coded video bitstream and determining one or more of a current picture width or a current picture height from one or more syntax elements S2 in the coded video bitstream. The method also includes determining that a virtual boundary syntax element in the coded video bitstream is encoded with a bit length derived from (i) one or more of the maximum picture width or the maximum picture height or (ii) one or more of the current picture width or the current picture height. The method also includes deriving the bit length for the virtual boundary syntax element based on (i) the one or more of the maximum picture width or maximum picture height as a result of determining that a virtual boundary syntax element in the coded video bitstream is encoded with a bit length derived from one or more of the maximum picture width or the maximum picture height or (ii) the one or more of the current picture width or the current picture height as a result of determining that a virtual boundary syntax element in the coded video bitstream is derived from one or more of the current picture width or the current picture height. The method also includes decoding the virtual boundary syntax element from the bitstream based on the derived bit length and determining a spatial picture position of the virtual boundary based on the decoded virtual boundary syntax element.

Virtual boundary signaling

A methods and apparatuses for encoding or decoding a segment in a coded picture. The decoding may include obtaining from a bitstream a value of a first codeword that indicates whether the coded picture may contain bi-directional inter coded segments or not. The decoding may include, based on the value of the first codeword, deriving one or more parameter values by either (a) decoding one or more parameters from the bitstream to obtain the one or more parameter values or (b) inferring the one or more parameter values. The decoding may include decoding the segment in the coded picture based on the one or more parameter values. The encoding may include encoding the first codeword to the bitstream and determining whether to encode one or more parameter values in the bitstream based on a determination of whether the coded picture will contain bi-directional inter coded segments or not.

Decoding based on bi-directional picture condition

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.

Allowing a matrix based intra prediction block to have multiple transform blocks

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.

Determining capability to decode a first picture in a video bitstream

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.

Bilateral loop filter

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. 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.

Motion refinement and weighted prediction

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.

Deblocking in a video encoder and/or video decoder

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.

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Solna, Sweden

Ruoyang Yu