An encoder includes circuitry and memory. The circuitry performs: obtaining first motion vector information of a first partition; obtaining second motion vector information of a second partition; deriving a set of prediction samples for the first partition; and encoding the first partition using the set. When the difference between the motion vector information is not greater than a value, the circuitry reflects a second set of samples to a first set of samples. The first set has been predicted for the first partition using the first motion vector information, and the second set has been predicted for a first range using the second motion vector information. When the difference is greater than the value, the circuitry reflects, to the first set of samples, a third set of samples predicted for a second range larger than the first range using the second motion vector information.

An encoder includes circuitry and memory. The circuitry performs: obtaining first motion vector information of a first partition; obtaining second motion vector information of a second partition; deriving a set of prediction samples for the first partition; and encoding the first partition using the set. When the difference between the motion vector information is not greater than a value, the circuitry reflects a second set of samples to a first set of samples. The first set has been predicted for the first partition using the first motion vector information, and the second set has been predicted for a first range using the second motion vector information. When the difference is greater than the value, the circuitry reflects, to the first set of samples, a third set of samples predicted for a second range larger than the first range using the second motion vector information.

Provided is an encoder that achieves further improvement. The encoder includes processing circuitry and memory. Using the memory, the processing circuitry: obtains two prediction images from two reference pictures; derives a luminance gradient value of each pixel position in each of the two prediction images; derives a luminance local motion estimation value of each pixel position in a current block; generates a luminance final prediction image using a luminance value and the luminance gradient value in each of the two prediction images, and the luminance local motion estimation value of the current block; and generates a chrominance final prediction image using at least one of the luminance gradient value of each of the two prediction images or the luminance local motion estimation value of the current block, and chrominance of each of the two prediction images.

A method of encoding a three-dimensional (3D) image including a point cloud includes grouping a plurality of points included in the point cloud into at least one segment; generating patches by projecting the points included in the segment onto a predetermined plane in a first direction or a second direction; generating two-dimensional (2D) images by packing the patches; and generating and outputting a bitstream including information about a direction in which each point is projected to generate the patches and information about the 2D images.

A motion information storing method comprises: determining a distance between a sample set in the current block and the common boundary; and comparing the distance with a threshold to determine whether third motion information is stored for the sample set, wherein the third motion information is derived by the first motion information and the second motion information.

Disclosed herein is a method for adaptive bidirectional optical flow estimation for inter prediction compensation during video encoding. The method aims to reduce complexity and/or cost of bidirectional optical flow (BIO) at a pixel level or a subblock level.

A method of video decoding includes creating a candidate list for a current block in current picture included in a coded video bitstream. The method further includes determining a coding mode for at candidate block associated with the current block. The method further it determining whether to add, to the candidate list, a vector associated the candidate block based on the determined coding mode. The method further includes reconstructing the current block using at least one candidate from the candidate list.

A mixed reality system including a head-mounted display (HMD) and a base station. Information collected by HMD sensors may be transmitted to the base via a wired or wireless connection. On the base, a rendering engine renders frames including virtual content based in part on the sensor information, and an encoder compresses the frames according to an encoding protocol before sending the frames to the HMD over the connection. Instead of using a previous frame to estimate motion vectors in the encoder, motion vectors from the HMD and the rendering engine are input to the encoder and used in compressing the frame. The motion vectors may be embedded in the data stream along with the encoded frame data and transmitted to the HMD over the connection. If a frame is not received at the HMD, the HMD may synthesize a frame from a previous frame using the motion vectors.

Devices, systems and methods for video processing are described. In one aspect, a video processing method is provided to include determining, for a conversion between a current video block of a video and a coded representation of the video, that a motion information of the current video block is refined using an optical flow-based method in which at least one motion vector offset is derived for a region within the current video block; clipping the at least one motion vector offset to a range [−N,M], wherein N and M are integers based on a rule; and performing the conversion based on at least one clipped motion vector offset.

A method of decoding a bitstream by an electronic device is provided. The method determines a block unit from an image frame received from the bitstream. To reconstruct the block unit, the method receives, from a candidate list, first motion information having a first list flag for selecting a first reference frame and second motion information having a second list flag for selecting a second reference frame. The method then stores a predefined one of the first and second motion information for a sub-block determined in the block unit when the first list flag is identical to the second list flag.