Syntax structures that indicate the completion of coded regions of pictures are described. For example, a syntax structure in an elementary bitstream indicates the completion of a coded region of a picture. The syntax structure can be a type of network abstraction layer unit, a type of supplemental enhancement information message or another syntax structure. For example, a media processing tool such as an encoder can detect completion of a coded region of a picture, then output, in a predefined order in an elementary bitstream, syntax structure(s) that contain the coded region as well as a different syntax structure that indicates the completion of the coded region. Another media processing tool such as a decoder can receive, in a predefined order in an elementary bitstream, syntax structure(s) that contain a coded region of a picture as well as a different syntax structure that indicates the completion of the coded region.

The present disclosure provides methods for performing wrap-around motion compensation. The method can include receiving a first wrap-around motion compensation flag, wherein the second wrap-around motion compensation flag is associated with a picture; determining whether the first wrap-around motion compensation flag is enabled; in response to a determination that the first wrap-around motion compensation flag is enabled, receiving a wrap-around motion compensation offset, wherein the wrap-around motion compensation offset is associated with the picture; and performing wrap-around motion compensation on the picture according to the first wrap-around motion compensation flag and the wrap-around motion compensation offset.

A picture prediction method includes receiving a bitstream, parsing the bitstream to obtain a prediction mode of a current block, when the prediction mode of the current block is a combined intra and inter prediction mode, selecting an execution manner of a triangular prediction unit mode according to a preset policy, determining motion information of the current block according to the execution manner of the triangular prediction unit mode, performing a motion compensation process based on the motion information, to obtain an inter prediction sample, obtaining an intra prediction sample according to the prediction mode of the current block, and combining the inter prediction sample and the intra prediction sample to obtain a prediction picture of the current block.

A picture prediction method includes receiving a bitstream, parsing the bitstream to obtain a prediction mode of a current block, when the prediction mode of the current block is a combined intra and inter prediction mode, selecting an execution manner of a triangular prediction unit mode according to a preset policy, determining motion information of the current block according to the execution manner of the triangular prediction unit mode, performing a motion compensation process based on the motion information, to obtain an inter prediction sample, obtaining an intra prediction sample according to the prediction mode of the current block, and combining the inter prediction sample and the intra prediction sample to obtain a prediction picture of the current block.

An example method of video processing includes performing a conversion between a video picture of a video and a bitstream representation of the video. The bitstream representation conforms to a format rule. The format rule specifies that applicability of a Decoder-side Motion Vector Refinement coding tool and a Bi-Directional Optical Flow coding tool for the video picture are indicated separately in the bitstream representation.

An example method of video processing includes performing a conversion between a video picture of a video and a bitstream representation of the video. The bitstream representation conforms to a format rule. The format rule specifies that applicability of a Decoder-side Motion Vector Refinement coding tool and a Bi-Directional Optical Flow coding tool for the video picture are indicated separately in the bitstream representation.

Various innovations in media encoding are presented herein. In particular, the innovations can reduce the computational complexity of encoding by selectively skipping certain evaluation stages during encoding. For example, based on analysis of decisions made earlier in encoding or based on analysis of media to be encoded, an encoder can selectively skip evaluation of certain coding tools (such as residual coding or rate-distortion-optimized quantization), skip evaluation of certain values for parameters or settings (such as candidate unit sizes or transform sizes, or candidate partition patterns for motion compensation), and/or skip evaluation of certain coding modes (such as frequency transform skip mode) that are not expected to improve rate-distortion performance during encoding.

Various innovations in media encoding are presented herein. In particular, the innovations can reduce the computational complexity of encoding by selectively skipping certain evaluation stages during encoding. For example, based on analysis of decisions made earlier in encoding or based on analysis of media to be encoded, an encoder can selectively skip evaluation of certain coding tools (such as residual coding or rate-distortion-optimized quantization), skip evaluation of certain values for parameters or settings (such as candidate unit sizes or transform sizes, or candidate partition patterns for motion compensation), and/or skip evaluation of certain coding modes (such as frequency transform skip mode) that are not expected to improve rate-distortion performance during encoding.

Methods and apparatus for image or video decoding in a video decoding system are disclosed. Input data associated with a current block coded with palette mode is received to parse a palette predictor run. A position of reused colors in a palette predictor table is computed according to the palette predictor run. A size of the palette predictor table is determined and compared with the position computed according to the palette predictor run to obtain a comparison result. The decoder applies palette decoding to the current block according to the comparison result. If the comparison result indicates the position computed according to the palette predictor run is not within the palette predictor table, the position is changed to a new position to indicate a corresponding reused color for the current block or a decoding process of palette predictor reuse flags is terminated.

An image decoding method according to the present invention comprises the steps of: referring to a first flag for indicating whether intra block-based delta pulse code modulation (BDPCM) signaled through a sequence parameter set is permitted, so as to determine whether a second flag for indicating whether the intra BDPCM is applied to a current block is parsed; determining whether the intra BDPCM is applied to the current block on the basis of the second flag; determining an intra BDPCM mode of the current block when it is determined that the intra BDPCM is applied to the current block; and acquiring a residual sample of the current block on the basis of the intra BDPCM mode.