Abstract: Provided are an inter prediction method and a motion compensation method. The inter prediction method includes: performing inter prediction on a current image by using a long-term reference image stored in a decoded picture buffer; determining residual data and a motion vector of the current image generated via the inter prediction; and determining least significant bit (LSB) information as a long-term reference index indicating the long-term reference image by dividing picture order count (POC) information of the long-term reference image into most significant bit (MSB) information and the LSB information.

Abstract: In some embodiments, a decoder may receive, in a bit stream and for a block of samples, a residual and an indication of a downscaling. The decoder may determine reference samples for intra prediction of the block of samples. The decoder may generate, for an intra prediction mode, a prediction of the block of samples from the reference samples, The decoder may generate a first decoded block of samples based on: the prediction of the block of samples; and the residual. Based on the indication of the downscaling, the decoder may upscale the first decoded block of samples to a second decoded block of samples.

Abstract: An example method of video processing includes performing a conversion between a picture of a video and a bitstream representation of the video. The picture includes one or more sub-pictures, and the bitstream representation conforms to a format rule that specifies that a length of a syntax element is equal to Ceil(Log 2(SS)) bits. SS is greater than 0, and the syntax element indicating a horizontal or a vertical position of a top-left corner of a coding tree unit of a sub-picture of the picture.

Abstract: 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.

Abstract: A method is disclosed for reconstructing a current block in units of sub-blocks included in the current block. The method includes: decoding transform coefficients in a transform block of the current block, sub-block information indicating a division form of the sub-blocks and transform type information indicating a transform type applied to the transform block from a bitstream; deriving a residual block of the current block from the transform coefficients on the basis of the transform type indicated by the transform type information and the sub-block information; and filtering boundaries of the sub-blocks in a reconstructed block of the current block derived on the basis of the residual block.

Abstract: A video decoding method performed by a decoding apparatus includes deriving one of a plurality of cross-component linear model (CCLM) prediction mode as a CCLM prediction mode of the current chroma block, deriving a sample number of neighboring chroma samples of the current chroma block based on the CCLM prediction mode of the current chroma block, a size of the current chroma block, and a specific value derived as 2. The method includes deriving the neighboring chroma samples of the sample number, calculating CCLM parameters based on the neighboring chroma samples and the down sampled neighboring luma samples, deriving prediction samples for the current chroma block based on the CCLM parameters and the down sampled luma samples and generating reconstructed samples for the current chroma block based on the prediction samples.

Abstract: Disclosed herein are a decoding method and apparatus and an encoding method and apparatus for deriving an intra-prediction mode. An intra-prediction mode may be derived using a method for deriving an intra-prediction mode based on a neighbor block of the target block, a method for deriving an intra-prediction mode using signaling of the intra-prediction mode of the target block, or a method for deriving an adaptive intra-prediction mode based on the type of a target slice. An MPM list may be used to derive the intra-prediction mode, and a temporal neighbor block or the like may be used to configure the MPM list.

Abstract: A method of decoding JVET video includes receiving a bitstream indicating how a coding tree unit was partitioned into coding units, and parsing said bitstream to generate at least one predictor based on an intra prediction mode signaled in the bitstream. The predictor may be generated by interpolating neighboring pixels for each pixel within a coding block. The computation may be more accurate by deriving a value for a bottom right neighboring pixel.

Abstract: A method is provided for inter-coding video in which transmission bandwidth requirements associated with second motion vectors for bi-directional temporal prediction is reduced. In the method, vector information for one of motion vectors for multi-directional temporal prediction can be transmitted together with information on how to derive or construct the second motion vectors. Thus, rather than sending express information regarding each of the plurality of motion vectors, express information related to only one motion vector along with information related to reconstruction/derivation of the second motion vectors is transmitted, thus reducing bandwidth requirements and increasing coding efficiency.

Abstract: A method of deriving intra prediction data based on a planar prediction mode includes the following operations: obtaining multiple first reconstructed row samples and a second reconstructed row sample in an adjacent above row to a current block, the first reconstructed row samples extending from first to last columns of the current block, the second reconstructed row sample corresponding to an adjacent right column to the current block; obtaining multiple first reconstructed column samples and a second reconstructed column sample in an adjacent left column to the current block, the first reconstructed column samples extending from first to last rows of the current block, the second reconstructed column sample corresponding to an adjacent below row to the current block; and deriving the intra prediction data corresponding to the current block based on a width and a height of the current block and the obtained reconstructed row and column samples.

Abstract: The present invention relates to an image encoding/decoding method and apparatus. The image decoding method according to the present invention may comprise configuring an MPM list based on intra-prediction modes of neighbor blocks of a current block and a number of frequencies of the intra-prediction modes of the neighbor blocks, deriving an intra-prediction mode of the current block based on the MPM list, and performing intra-prediction for the current block based on the intra-prediction mode.

Abstract: A remote device utilizes ray tracing to compute a light field for a scene to be rendered, where the light field includes information about light reflected off surfaces within the scene. This light field is then compressed utilizing one or more video compression techniques that implement temporal reuse, such that only differences between the light field for the scene and a light field for a previous scene are compressed. The compressed light field data is then sent to a client device that decompresses the light field data and uses such data to obtain the light field for the scene at the client device. This light field is then used by the client device to compute global illumination for the scene. The global illumination may be used to accurately render the scene at the mobile device, resulting in a realistic scene that is presented by the mobile device.

Abstract: A method for video encoding includes determining whether coding of a current block in an IBC prediction mode is performed in an explicit mode or an implicit mode based on whether a difference exists between a block vector and a corresponding block vector predictor. The current block is part of a current picture to be coded. The method further includes constructing a block vector predictor candidate list for the current block, the block vector predictor candidate list having a first number of block vector predictor candidates in the implicit mode, and having a second number of block vector predictor candidates in the explicit mode. The method further includes selecting a block vector predictor candidate from the constructed block vector predictor candidate list and encoding the current block according to the selected block vector predictor candidate.

Abstract: A method of performing intra prediction of a current block of a picture of a video sequence, includes determining whether a first flag indicates that an intra prediction mode corresponding to the current block is a directional mode, and based on the first flag being determined to indicate that the intra prediction mode corresponding to the current block is the directional mode, determining an index of the intra prediction mode in an allowed intra prediction modes (AIPM) list, and performing the intra prediction of the current block, using the intra prediction mode corresponding to the determined index in the AIPM list.

Abstract: A method and apparatus for inter prediction. According to the position of a current block in a video picture, first motion information and second candidate motion information is determined, the motion information at least includes a motion vector; it is determined whether the distance between the motion vector of the first motion information and the motion vector of the second candidate motion information is greater than a first threshold; if the determination result is that the distance is less than or equal to the first threshold, the second candidate motion information is updated to obtain second motion information; if the determination result is that the distance is greater than the first threshold, the second candidate motion information is taken as the second motion information; and inter prediction is performed on the current block by using the first motion information and the second motion information.

Abstract: Extensions of intra coding modes in video coding are described. One example is a method for video processing, comprising: generating, for a conversion between a current video block of a video and a bitstream representation of a video, a set of extended intra prediction modes (IPMs) associated with the current video block by revising a set of existing IPMs to include at least one new coding method, wherein the new coding method is different from coding methods in the existing IPMs and is to be treated as IPM; and performing the conversion based on the set of extended IPMs.

Abstract: An example method of video processing includes performing a conversion between a picture of a video and a bitstream representation of the video. The picture includes one or more sub-pictures, and the bitstream representation conforms to a format rule that specifies that a length of a syntax element is equal to Ceil(Log 2(SS)) bits. SS is greater than 0, and the syntax element indicating a horizontal or a vertical position of a top-left corner of a coding tree unit of a sub-picture of the picture.

Abstract: Provided is an encoder which includes circuitry and memory. Using the memory, the circuitry splits an image block into a plurality of partitions, obtains a prediction image for a partition, and encodes the image block using the prediction image. When the partition is not a non-rectangular partition, the circuitry obtains (i) a first prediction image for the partition, (ii) a gradient image for the first prediction image, and (iii) a second prediction image as the prediction image using the first prediction image and the gradient image. When the partition is a non-rectangular partition, the circuitry obtains the first prediction image as the prediction image without using the gradient image.

Abstract: An encoder includes circuitry and memory. Using the memory, the circuitry performs prediction on an image. A motion vector predictor list used in the prediction includes a spatially neighboring motion vector predictor obtained from a block spatially neighboring a current block, and a spatially broad motion vector predictor obtained from a block positioned at any of a plurality of predetermined positions in a second range that is broader than a first range that spatially neighbors the current block. The plurality of predetermined positions are defined by a regular interval using the top-left of a current picture as a reference point.

Abstract: One variation of a method for video conferencing includes, at a first device associated with a first user: capturing a first video feed; representing constellations of facial landmarks, detected in the first video feed, in a first feed of facial landmark containers; and transmitting the first feed of facial landmark containers to a second device. The method further includes, at the second device associated with a second user: accessing a first face model representing facial characteristics of the first user; accessing a synthetic face generator; transforming the first feed of facial landmark containers and the first face model into a first feed of synthetic face images according to the synthetic face generator; and rendering the first feed of synthetic face images.

Abstract: A method and a device for decoding a data stream representative of a multi-view video. Syntax elements are obtained from at least one part of the stream data, and used to reconstruct at least one image of a view of the video. Then, at least one item of metadata in a predetermined form is obtained from at least one obtained syntax element, and provided to an image processing module. Also, a method and a device for processing images configured to read the at least one item of metadata in the predetermined form and use it to generate at least one image of a virtual view from a reconstructed view of the multi-view video.

Abstract: An image encoder/decoder includes circuitry and a memory coupled to the circuitry. When a geometry of a block of a picture satisfies a first condition, the circuitry splits the block of the picture into sub blocks having a first set of geometries. When the geometry of the block does not satisfy the first condition, the circuitry splits the block of the picture into sub blocks having a second set of geometries, the second set of geometries being different from the first set of geometries. The circuitry encodes/decodes the sub blocks of the block.

Abstract: A method, computer program, and computer system is encoding or decoding video data. Video data may include a syntax element indicating a quantization index, wherein a range of the quantization index is extended by an offset value. The syntax element may be parsed to determine the quantization index, a quantization step size may be obtained from a lookup table based on the quantization index and the offset value; and the video data may be encoded or decoded based on the quantization step size.

Abstract: The present invention relates to an image encoding/decoding method and apparatus. An image decoding method performing intra prediction according to the present invention may comprise dividing a current block into at least one sub-block; deriving an intra prediction mode for the at least one sub-block; constructing a reference sample for the intra prediction; and performing intra prediction for the at least one sub-block based on the derived intra prediction mode.

Abstract: Provided is an encoder which includes circuitry and memory. Using the memory, the circuitry splits an image block into a plurality of partitions, obtains a prediction image for a partition, and encodes the image block using the prediction image. When the partition is not a non-rectangular partition, the circuitry obtains (i) a first prediction image for the partition, (ii) a gradient image for the first prediction image, and (iii) a second prediction image as the prediction image using the first prediction image and the gradient image. When the partition is a non-rectangular partition, the circuitry obtains the first prediction image as the prediction image without using the gradient image.

Abstract: The present invention concerns a method of encoding video data comprising frames into a bitstream, frames being spatially divided into frame portions, the method comprising: encoding at least one frame portion into one or more first encoded units; wherein the method further comprises: signalling into said first encoded units, at least one frame portion identifier, a frame portion identifier identifying one encoded frame portion; and providing frame portion arrangement information comprising the frame portion identifier and spatial information about the frame portion.

Abstract: An image encoding/decoding method and apparatus of the present invention may divide one picture into a plurality of division units, determine whether to perform filtering on a boundary of a current division unit based on a predetermined flag, and perform filtering on the boundary of the current division unit in response to the determination.

Abstract: An image decoder includes circuitry and a memory, wherein the circuitry, in operation, calculates first values of a first partition in a current block, using a first motion vector for the first partition; calculates second values of a second partition in the current block, using a second motion vector for the second partition; calculates third values of a set of pixels between the first partition and the second partition, using the first motion vector; calculates fourth values of the set of pixels, using the second motion vector; and weights the third values and the fourth values. A number of pixels in a row in the set of pixels is two or more, and two or more weights applied to the third values increase along the row.

Abstract: An intra-frame decoding method includes obtaining, from a video code stream, prediction mode information of a first signal component of a current block, determining a prediction mode of the first signal component of the current block from a prediction mode set of the first signal component of the current block according to the prediction mode information of the first signal component of the current block, where the prediction mode set of the first signal component of the current block includes at least one of a linear model above (LMA) mode and a linear model left (LML) mode; obtaining a predicted value of a first signal component sampling point of the current block; and obtaining a reconstructed value of the first signal component sampling point of the current block according to the predicted value of the first signal component sampling point of the current block.

Abstract: A storage system, including a storage device configured to store a plurality of encoded values, wherein each value of the plurality of encoded values has a predetermined value length and is within a predetermined range, and wherein the predetermined range is not a power of 2; and at least one processor configured to: group the plurality of encoded values into a codeword; obtain a plurality of bit chunks, wherein each bit chunk of the plurality of bit chunks represents a corresponding encoded value of the plurality of encoded values, and wherein a length of the each bit chunk is selected from among one or more predetermined bit chunk lengths which are determined based on the predetermined range; select a variable-length prefix from among a plurality of variable-length prefixes, wherein the variable-length prefix indicates bit chunk lengths of the plurality of bit chunks; obtain a compressed codeword including the variable-length prefix and the plurality of bit chunks; and decode the plurality of encoded values

Abstract: An example method of video processing includes performing a conversion between a picture of a video and a bitstream representation of the video. The picture includes one or more sub-pictures, and the bitstream representation conforms to a format rule that specifies that a length of a syntax element is equal to Ceil(Log 2(SS)) bits. SS is greater than 0, and the syntax element indicating a horizontal or a vertical position of a top-left corner of a coding tree unit of a sub-picture of the picture.

Abstract: A method for decoding an image signal according to the present invention may comprise the steps of: determining whether there is a brightness change between a current image including a current block and a reference image of the current image; if it is determined that there is a brightness change between the current image and the reference image, determining weight prediction parameter candidates for the current block; determining a weight prediction parameter for the current block on the basis of index information which specifies any one of the weight prediction parameter candidates; and performing a prediction on the current block on the basis of the weight prediction parameter.

Abstract: A method of decoding a coded video bitstream implemented by a video decoder is provided. The method includes the video decoder determining whether a gradual decoding refresh (GDR) picture in the coded video bitstream is an initial picture in decoding order or the initial picture following an end of sequence (EOS) network abstraction layer (NAL) unit in the decoding order; setting a flag to a value to prevent the GDR picture from being output when the GDR picture is the initial picture in decoding order or the initial picture following the EOS NAL unit in the decoding order; decoding the GDR picture; and storing the GDR picture in a decoded picture buffer (DPB).

Abstract: A method for decoding an image based on an intra prediction, comprising: obtaining a first prediction pixel of a first region in a current block by using a neighboring pixel adjacent to the current block; obtaining a second prediction pixel of a second region in the current block by using the first prediction pixel of the first region; and decoding the current block based on the first and the second prediction pixels.

Abstract: Methods, systems and devices for implementing constraints used in video encoding and video decoding are described. An example method of video processing includes performing a conversion between a video comprising one or more pictures comprising one or more slices and a bitstream of the video. The conversion conforms to a rule, and the bitstream is organized into one or more access units. The rule specifies a constraint on a number of decoded pictures stored in a decoded picture buffer (DPB). Each decoded picture of the decoded pictures is (i) marked as used for reference, (ii) has a flag indicative of the decoded picture being output, and (iii) has an output time later than a decoding time of a current picture.

Abstract: Techniques for implementing video processing techniques are described. In one example implementation, a method of video processing includes determining, for a conversion between a current block of a video and a bitstream representation of the video, whether a combined inter and intra prediction (CIIP) coding technique is to be applied to the current block based on a characteristic of the current block. The CIIP coding technique uses an intermedia inter prediction value and an intermedia intra prediction value to derive a final prediction value of the current block. The method also includes performing the conversion based on the determining.

Abstract: A method for video processing is provided to include: determining a motion vector precision of one or more motion vectors related to a current video block of a video; selecting, based on the motion vector precision, a motion vector range; and performing, based on the motion vector range, a conversion between the current video block and a bitstream representation of the video.

Abstract: The present invention relates to a method and apparatus for setting a reference picture index of a temporal merging candidate. An inter-picture prediction method using a temporal merging candidate can include the steps of: determining a reference picture index for a current block; and inducing a temporal merging candidate block of the current block and calculating a temporal merging candidate from the temporal merging candidate block, wherein the reference picture index of the temporal merging candidate can be calculated regardless of whether a block other than the current block is decoded. Accordingly, a video processing speed can be increased and video processing complexity can be reduced.

Abstract: Provided is an encoder which includes circuitry and memory. The circuitry encodes an image block using the memory. In encoding the image block, the circuitry: obtains one or more size parameters related to a size of the image block; determines whether the one or more size parameters and one or more thresholds satisfy a determined relationship; encodes a split parameter when the one or more size parameters and the one or more thresholds are determined to satisfy the determined relationship, the split parameter indicating whether the image block is to be split into a plurality of partitions including a non-rectangular partition; and encodes the image block after splitting the image block into the plurality of partitions when the split parameter indicates that the image block is to be split into the plurality of partitions.

Abstract: Devices, systems and methods for applying intra-block copy (IBC) in video coding are described. In general, methods for integrating IBC with existing motion compensation algorithms for video encoding and decoding are described. In a representative aspect, a method for video encoding using IBC includes determining whether a current block of the current picture is to be encoded using a motion compensation algorithm, and encoding, based on the determining, the current block by selectively applying an intra-block copy to the current block. In a representative aspect, another method for video encoding using IBC includes determining whether a current block of the current picture is to be encoded using an intra-block copy, and encoding, based on the determining, the current block by selectively applying a motion compensation algorithm to the current block.

Abstract: Provided is an encoder which includes circuitry and memory. Using the memory, the circuitry splits an image block into a plurality of partitions, obtains a prediction image for a partition, and encodes the image block using the prediction image. When the partition is not a non-rectangular partition, the circuitry obtains (i) a first prediction image for the partition, (ii) a gradient image for the first prediction image, and (iii) a second prediction image as the prediction image using the first prediction image and the gradient image. When the partition is a non-rectangular partition, the circuitry obtains the first prediction image as the prediction image without using the gradient image.

Abstract: An encoder which encodes a current block of a picture includes a processor and memory. Using the memory, the processor: determines whether intra prediction is to be used for the current block; and when it is determined that intra prediction is to be used for the current block, generates first transform coefficients by performing first transform of residual signals of the current block using a first transform basis; quantizes the first transform coefficients when an intra prediction mode for the current block is a determined mode and the first transform basis is different from a determined transform basis; and generates second transform coefficients by performing second transform of the first transform coefficients using a second transform basis, and quantizes the second transform coefficients, when the intra prediction mode for the current block is not the determined mode or when the first transform basis matches the determined transform basis.

Abstract: A video signal decoding method according to the present disclosure includes partitioning a current picture into a plurality of tiles, decoding partitioning information representing a slice type, wherein the partitioning information represents whether a rectangular slice is applied, decoding width information and height information for a first slice, decoding tile index difference value information for the first slice and determining an index of a top-left tile of a second slice based on the difference value information.

Abstract: There is provided an image encoding/decoding method and apparatus. An image decoding method according to the present invention may comprise reconstructing a most frequent mode (MFM) indicator indicating whether or not an intra prediction mode of a current block is a predetermined intra prediction mode, deriving, on the basis of the MFM indicator, the intra prediction mode of the current block, and generating a prediction block of the current block by performing intra prediction on the current block on the basis of the intra prediction mode.

Abstract: Disclosed are a method and apparatus for decoding an image using inter-prediction. The method of decoding an image using inter-prediction includes receiving a bitstream; acquiring a portion of information indicating a motion vector of a current block to be decoded in the received bitstream, obtaining the motion vector of the current block by using the acquired information to determine the remaining information other than the portion, and generating a prediction block for the current block through inter-prediction that uses the motion vector of the current block. Therefore, it is possible to improve image decoding/encoding efficiency.

Abstract: A method for decoding a video according to the present invention may comprise: determining merge target candidate blocks of a current coding block, specifying at least one among the merge target candidate blocks, and generating a merged block by merging the specified merge target candidate block and the current coding block.

Abstract: A method for motion estimation is provided that includes determining a first motion vector for a first child coding unit (CU) of a parent CU and a second motion vector for a second child CU of the parent CU, wherein the first child CU, the second child CU, and the parent CU are in a CU hierarchy, wherein the first and second child CUs are smallest size CUs in the CU hierarchy, and wherein a first motion search type is used to determine the first motion vector and the second motion vector, selecting the first and second motion vectors as candidate predictors for the parent CU, selecting a predictor for a prediction unit (PU) of the first parent CU from the candidate predictors, and refining the predictor using a second motion search type to determine a motion vector for the PU.

Abstract: An image decoding method, according to the present invention, may comprise the steps of: splitting a current picture into a plurality of tiles; decoding split information indicating slice type, wherein the split information indicates whether a square-shaped slice is applied; and determining a slice on the basis of tile index difference information if the split information indicates that the square-shaped slice is applied.

Abstract: An image encoding/decoding method and apparatus for performing intra prediction are provided. An image decoding method of the present invention comprises deriving an intra-prediction mode for a current block, determining whether or not a left boundary or an upper boundary of the current block is a boundary of a predetermined image region, configuring a reference sample by using at least one reconstructed sample included in at least one reconstructed sample line adjacent to the current block based on the determination result, and performing intra-prediction for the current block based on the intra-prediction mode and the reference sample.

Abstract: A video processing method includes performing a conversion between a video and a bitstream of the video. The bitstream conforms to a format rule specifying a condition that controls whether or how one or more syntax elements related to picture order counts for a long term reference picture are included in a reference picture list syntax structure in the bitstream.