Abstract: A method and apparatus for video encoding using improved last significant coefficient coding are disclosed. According to the present invention, a location of last significant coefficient in the transform block is encoded to generate one or more syntax elements and a maximum value of the syntax elements is dependent on a block size of the transform block and a zero-out threshold, where coefficients of the transform block with coordinates greater than the zero-out threshold are set to zero. A method and apparatus for video decoding using improved last significant coefficient coding are also disclosed.

Abstract: A video coding method using inter-layer prediction or referencing is provided. A video decoder receives data from a bitstream carrying data for video pictures in a plurality of different layers. At least one of the plurality of layers comprises temporal sublayers that correspond to levels in a hierarchical temporal prediction structure. Each temporal sublayer is associated with a temporal identifier. The video decoder receives an inter-layer prediction constraint parameter constraining a maximum temporal sublayer used in inter-layer prediction. The video decoder reconstructs a first picture in a first layer by referencing data of a second picture in a second layer. A temporal identifier of the referenced data satisfies the received inter-layer prediction constraint parameter.

Abstract: Method and apparatus of coding a video sequence, are disclosed. According to the method, a bitstream corresponding to encoded data of the video sequence is generated at an encoder side or received at a decoder side, where the bitstream complies with a bitstream conformance that one or more constraints are satisfied. The constraints are related to a set of RPR (Reference Picture Resampling) parameters including scaling window width or height of a current picture, scaling window width or height of a reference picture, current picture width or height, and maximum picture width or height specified for the video sequence. Scaling information for the RPR mode is derived using the set of RPR parameters. A target picture of the video sequence is then encoded at the encoder side or decoded at the decoder side by utilizing the scaling information when the RPR mode is enabled for the target picture.

Abstract: Encoding methods and apparatuses include applying a Cross-Component Adaptive Loop Filter (CCALF) processing on a current picture based on CCALF coefficients signaled in one or more Adaptive Loop Filter (ALF) Adaptation Parameter Sets (APSs) to refine one or more chroma components according to a luma component, signaling two ALF signal flags and two CCALF signal flags in each ALF APS or parsing two ALF signal flags and two CCALF signal flags from each ALF APS, and encoding or decoding the current picture. Values of the two ALF signal flags and the two CCALF signal flags in each ALF APS are not all equal to 0 to ensure none of the ALF APS is an empty APS.

Abstract: Methods and apparatus for video coding are disclosed. According to one method, a bitstream is generated or received, where the bitstream includes a first syntax and a second syntax. The first syntax is related to a target number of bits used to represent a set of third syntaxes and each third syntax specifies one subpicture ID for one subpicture in a set of subpictures. The second syntax is related to a total number of subpictures in the set of subpicture, where a first number that can be represented by the target number of bits is equal to or greater than the total number of subpictures. According to another method, the subpicture ID syntaxes have different values for different subpictures.

Abstract: A method for signaling scaling matrices for transform coefficient quantization is provided. A decoder receives data from a bitstream to be decoded as a current picture of a video, the current picture to be decoded by using a plurality of scaling matrices. The decoder receives a reference index offset for a first scaling matrix of the plurality of scaling matrices. The decoder applies the reference index offset to a first index identifying the first scaling matrix to derive a second index identifying a second scaling matrix of the plurality of scaling matrices. The second scaling matrix is previously reconstructed. The decoder reconstructs the first scaling matrix by referencing the second scaling matrix. The decoder dequantizes transform coefficients of transform blocks of the current picture by using the plurality of scaling matrices and reconstructs the current picture by using the dequantized transform coefficients.

Abstract: Methods and apparatus for cross-colour loop-filter processing of reconstructed video are disclosed. According to one method, a sum of filter coefficients for each of one or more candidate cross-colour loop filters is constrained to be a fixed value. One or more syntax elements indicating a value related to a total number of candidate filters in a filter set are signalled or parsed in the APS (Adaptation Parameter Set).

Abstract: A method for signaling scaling matrices for transform coefficient quantization is provided. A video decoder receives data from a bitstream to be decoded as a current picture of a video. The video decoder determines a plurality of scaling matrices that are used to code the current picture, wherein a first scaling matrix of the plurality of scaling matrices is determined by referencing a previously determined second scaling matrix of the plurality of scaling matrices. The video decoder dequantizes transform coefficients of transform blocks of the current picture by using the determined plurality of scaling matrices. The video decoder reconstructs the current picture by using the dequantized transform coefficients.

Abstract: A method for performing transform skip mode (TSM) in a video decoder is provided. A video decoder receives data from a bitstream to be decoded as a plurality of video pictures. The video decoder parses the bitstream for a first syntax element in a sequence parameter set (SPS) of a current sequence of video pictures. When the first syntax element indicates that transform skip mode is allowed for the current sequence of video pictures and when transform skip mode is used for a current block in a current picture of the current sequence, the video decoder reconstructs the current block by using quantized residual signals that are not transformed.

Abstract: A method and apparatus for video coding are disclosed. According to the present invention, a flag is determined, where the flag indicates whether a scaling matrix is enabled or not enabled for non-separable secondary transform (NSST) coded blocks. When the current block is one NSST coded block and the flag indicates that the scaling matrix is enabled for the NSST blocks, the scaling matrix is determined and applied to the current block. When the current block is one NSST coded block and the flag indicates that the scaling matrix is not enabled for the NSST coded blocks, the scaling matrix is skipped for the current block. According to another method, for a rectangular block, a target scaling matrix is generated directly from a square base scaling matrix in one step without up-sampling-and-down-sampling or down-sampling-and-up-sampling.