A point cloud encoding method includes the following. For one or more points in the current coding block, an optimal prediction mode is determined by using a RDO mechanism, where a distortion parameter D in the RDO mechanism is determined according to a reconstruction distortion, and a bitrate parameter R in the RDO mechanism is determined according to a bitrate. A prediction value of the one or more points is determined by predicting the one or more points using the optimal prediction mode. A residual of the one or more points is determined according to the prediction value of the one or more points. Encoding bits are determined by encoding according to the optimal prediction mode and the residual, and the encoding bits are signaled into a bitstream.

A point cloud encoding method includes the following. For one or more points in the current coding block, an optimal prediction mode is determined by using a RDO mechanism, where a distortion parameter D in the RDO mechanism is determined according to a reconstruction distortion, and a bitrate parameter R in the RDO mechanism is determined according to a bitrate. A prediction value of the one or more points is determined by predicting the one or more points using the optimal prediction mode. A residual of the one or more points is determined according to the prediction value of the one or more points. Encoding bits are determined by encoding according to the optimal prediction mode and the residual, and the encoding bits are signaled into a bitstream.

A point cloud coding method, including: partitioning a point cloud, and determining a current coding block; determining a quantization parameter optimization enable identifier, a hierarchical level index, and a quantization parameter offset parameter of the current coding block; determining, according to the hierarchical level index and the quantization parameter offset parameter, a quantization step Qstep corresponding to a level of detail; and upon detecting that the quantization parameter optimization enable identifier is a first value, performing operations for one or more points included in the current coding block.

Provided is a video decoding method including: obtaining, from a sequence parameter set, sequence merge mode with motion vector difference (sequence MMVD) information indicating whether an MMVD mode is applicable in a current sequence; when the MMVD mode is applicable according to the sequence MMVD information, obtaining, from a bitstream, first MMVD information indicating whether the MMVD mode is applied in a first inter prediction mode for a current block included in the current sequence; when the MMVD mode is applicable in the first inter prediction mode according to the first MMVD information, reconstructing a motion vector of the current block which is to be used in the first inter prediction mode, by using a distance of a motion vector difference and a direction of a motion vector difference obtained from the bitstream; and reconstructing the current block by using the motion vector of the current block.

Provided is a video decoding method including: obtaining, from a sequence parameter set, sequence merge mode with motion vector difference (sequence MMVD) information indicating whether an MMVD mode is applicable in a current sequence; when the MMVD mode is applicable according to the sequence MMVD information, obtaining, from a bitstream, first MMVD information indicating whether the MMVD mode is applied in a first inter prediction mode for a current block included in the current sequence; when the MMVD mode is applicable in the first inter prediction mode according to the first MMVD information, reconstructing a motion vector of the current block which is to be used in the first inter prediction mode, by using a distance of a motion vector difference and a direction of a motion vector difference obtained from the bitstream; and reconstructing the current block by using the motion vector of the current block.

A method of video decoding performed in a video decoder. The method including receiving a coded video bitstream including a current picture. The method further including, performing an inverse quantization on a current block included in the current picture. The method further including performing, after performing the inverse quantization, an inverse transform on the current block. The method further including performing a prediction process on the current block after performing the inverse transform. The method further including, after performing the prediction process on the current block, determining whether a predetermined condition is satisfied. The method further including, in response to determining that the predetermined condition is met, performing an inverse color transform on the current block.

A video image decoding device receives, as the code string to be decoded, a first code string to be decoded including information based on an encoded residual coefficient and header information or a second code string to be decoded including a residual image obtained in encoding the code string to be decoded and header information. The video image decoding device, when the code string to be decoded that is received by the receiver is the first code string to be decoded, adds the residual decoded image and the predictive image to each other to generate and output a reconstructed image and, when the code string to be decoded received by the receiver is the second code string to be decoded, adds a residual image included in the second code string to be decoded and the predictive image to each other to generate and output a reconstructed image.

A video image decoding device receives, as the code string to be decoded, a first code string to be decoded including information based on an encoded residual coefficient and header information or a second code string to be decoded including a residual image obtained in encoding the code string to be decoded and header information. The video image decoding device, when the code string to be decoded that is received by the receiver is the first code string to be decoded, adds the residual decoded image and the predictive image to each other to generate and output a reconstructed image and, when the code string to be decoded received by the receiver is the second code string to be decoded, adds a residual image included in the second code string to be decoded and the predictive image to each other to generate and output a reconstructed image.

According to an embodiment of the present invention, there is provided an image decoding method including: obtaining an arithmetic-coded symbol stream from an image stream; identifying a symbol segment from the symbol stream according to symbol segment information signaled from an encoding apparatus; selecting an arithmetic decoding process corresponding to the symbol segment; and collectively processing one or more symbols among multiple symbols included in the symbol segment, in association with the selected arithmetic decoding process.

According to an embodiment of the present invention, there is provided an image decoding method including: obtaining an arithmetic-coded symbol stream from an image stream; identifying a symbol segment from the symbol stream according to symbol segment information signaled from an encoding apparatus; selecting an arithmetic decoding process corresponding to the symbol segment; and collectively processing one or more symbols among multiple symbols included in the symbol segment, in association with the selected arithmetic decoding process.