Abstract: Methods and apparatus for Adaptive Loop Filter (ALF) processing of reconstructed video are disclosed. According to one method, clipping values for the ALF processing are determined depending on a bit depth of a center reconstructed pixel. A current ALF output for the current block is derived, where the current ALF output comprises a weighted sum of clipped differences of original differences and each of the original differences is calculated between a first reconstructed pixel at a non-center filter location and the center reconstructed pixel, and each of the original differences is clipped according to a corresponding clipping value to form one clipped difference. In another method, a target clipping value is always signaled at an encoder side or parsed at a decoder side even if the target clipping value is zero. In another method, the clipping values are encoded or decoded using a fixed-length code.

Abstract: Encoding methods and apparatuses include receiving input video data of a current block in a current picture and applying a Cross-Component Adaptive Loop Filter (CCALF) processing on the current block based on cross-component filter coefficients to refine chroma components of the current block according to luma sample values. The method further includes signaling two Adaptive Loop Filter (ALF) signal flags and two CCALF signal flags in an Adaptation Parameter Set (APS) with an APS parameter type equal to ALF or parsing two ALF signal flags and two CCALF signal flags from an APS with an APS parameter type equal to ALF, signaling or parsing one or more Picture Header (PH) CCALF syntax elements or Slice Header (SH) CCALF syntax elements, wherein both ALF and CCALF signaling are present either in a PH or SH, and encoding or decoding the current block in the current picture.

Abstract: Exemplary video processing methods and apparatuses for encoding or decoding a current block by bi-directional prediction. Multiple weight sets are utilized for blending List 0 and List 1 predictors, and the selection among multiple weight sets may be implicitly determined based on video information. Each weight set is composed of multiple candidate weights, and one candidate weight is selected for the current block. A weight pair associated with the selected weight for the current block is used for weighted averaging List 0 and List 1 predictors of the current block to generate a final inter predictor. The video processing methods and apparatuses encode or decode the current block according to the final inter predictor of the current block.

Abstract: A method and apparatus of video encoding video coding for a video encoder or decoder using Neural Network (NN) are disclosed. According to this method, the multiple frames in a video sequence comprises multiple segments, where each of the multiple segments comprises a set of frames. The NN (Neural Network) processing is applied to a target signal in one or more encoded frames of a target segment in the encoder side or to the target signal in one or more decoded frames of the target segment in the decoder side using one NN parameter set for the target segment. The target signal may correspond to reconstructed residual, reconstructed output, de-blocked output, SAO (sample adaptive offset) output, ALF (adaptive loop filter) output, or a combination thereof. In another embodiment, the NN processing is applied to a target signal only in one or more specific encoded or decoded frames.

Abstract: A method of video coding with reduced implementation cost by reusing transform coefficient buffer palette for palette coding is disclosed. If the current prediction mode is an Intra prediction mode or the Inter prediction mode, information related to transform coefficients for prediction residual of the current block resulted from Intra prediction or Inter prediction is stored in the transform coefficient buffer. If the current prediction mode is the palette coding mode, information related to palette data associated with the current block is stored in the transform coefficient buffer. The current block is then encoded or decoded based on the information related to the transform coefficients if the current block is coded in the Intra prediction mode or the Inter prediction mode, or the information related to the palette data stored in the transform coefficient buffer if the current prediction mode is the palette coding mode.

Abstract: Methods and apparatus for video coding are disclosed. According to one method, First ALF (Adaptive Loop Filter) processing is applied to the reconstructed chroma samples for a target reconstructed chroma sample to generate a first filtered chroma sample. Second ALF processing is applied to the related reconstructed luma samples to generate a second filtered chroma sample for the target reconstructed chroma sample, where positions of the related reconstructed luma samples selected for the second ALF processing are determined according to the target chroma format. According to another method, the luma ALF and the cross-component ALF have the same filter coefficient precision.

Abstract: Methods and apparatus for video coding using Adaptive Loop Filter (ALF) processing are disclosed. According to one method, the ALF virtual boundary processing is always applied to the bottom CTU row regardless whether the bottom CTU row is for a picture or a sub-picture. In another method, the ALF padding process is unified for different boundary types belonging to the target boundary belongs to a boundary-type group comprising two or more of slice boundary, tile boundary, VR360 face boundary, and sub-picture boundary. In yet another method, the ALF VB processing has a fixed priority for a corner region that both horizontal and vertical virtual boundaries can be applied.

Abstract: A video coder implementing affine prediction is provided. The video coder receives input data associated with a current block to be coded. The video coder derives a control point motion vector (CPMV) of the current block according to an affine model. The video coder derives a set of motion compensation motion vectors (MCMVs) for a set of sub-blocks of the current block based on the derived CPMV of the current block according to the affine model. The video coder performs motion compensation for the current block based on the set of MCMVs. The CPMV of the current block is derived based on a CPMV of a first reference block that is a neighboring block located in a same region of the current block or an MCMV of a second reference block that is not a neighboring block located in the same region of the current block.

Abstract: Method and apparatus of coding a video sequence are disclosed, wherein Reference Picture Resampling (RPR) mode is included as a coding tool. According to the method, a bitstream corresponding to encoded data of the video sequence is generated or received, where the bitstream includes one or more syntaxes related to the RPR mode when the RPR mode is enabled, and scaling information for the RPR mode is derived using first information including said one or more syntaxes, and wherein said one or more syntaxes are constrained by taking into account a value corresponding to Max(8, (minimum coding block size for a luma component)). A target picture of the video sequence is encoded or decoded utilizing the scaling information when the RPR mode is enabled for the target picture.

Abstract: Method and apparatus of video coding using a multi-layer prediction mode, are disclosed. According to one method, a bitstream is generated at an encoder side or received at a decoder side, where the bitstream corresponds to coded data of current video data in a current layer. The bitstream complies with a bitstream conformance requirement corresponding both the bit depth values for the current layer and the reference layer being the same and the chroma format index values for the current layer and the reference layer being the same. The current video data in the current layer is then encoded or decoded by utilizing reference video data in the reference layer.

Abstract: A method and apparatus of video coding are disclosed. According to one method of the present invention, a root block comprising one luma component and one or more chroma components in a 420 or 422 chroma format is received at the encoder side or compressed data comprising the root block at the decoder side. A target mode type is determined for all of the child blocks within the root block when one or more conditions are satisfies. The conditions comprise a child block width equal to 2 or a child block less than 16 for the chroma components. If Intra type mode is not selected for an image area enclosing the root block, the target mode type corresponds to the Intra or Inter type mode and otherwise, the target mode type corresponds to the Intra type mode. The child blocks in the root block are encoded or decoded accordingly.

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: Video data processing methods and apparatuses comprise receiving input data associated with a current chroma block, determine a luma Quantization Parameter (QP) of a collocated luma block, reuse the luma QP of the collocated luma block to derive a chroma QP for the current chroma block, and encode or decode one or more Transform Units (TUs) associated with the current chroma block using the chroma QP. The collocated luma block is a block that covers a collocated sample of one predefined sample of the current chroma block, and an example of the predefined sample is a center sample of the current chroma block. The input video data is partitioned according to two separate Coding Unit (CU) partitioning structures for luma and chroma components when dual tree coding is enabled.

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 loop-filter processing of reconstructed video are disclosed. According to this method, if a loop-filter is disallowed for a target boundary, the target loop filter is disabled at top, bottom, left and right of the target boundary. According to another method, CC-ALF (cross-component adaptive loop filter) shape is changed across a virtual boundary. According to yet another method, CC-ALF and luma ALF handle unavailable samples in a same way.

Abstract: A method and apparatus of video coding are disclosed. According to this method, input data related to a current block in a current picture are received at a video encoder side or compressed data comprising the current block are received at a video decoder side. A first syntax at a high level in a video bitstream regarding residual coding type is signaled at the encoder side or parsed at the decoder side. A target coding mode is determined for the current block based on information comprising a value of the first syntax. The current block is encoded at the encoder side or decoded at the decoder side according to the target coding mode. The high level may correspond to a slice header or a picture header.

Abstract: A method and apparatus of entropy coding of coding symbols using Context-Based Adaptive Binary Arithmetic Coder (CABAC) are disclosed. The method operates by applying context-adaptive arithmetic encoding or decoding to a current bin of a binary data of a current coding symbol according to a current binarized probability value of the current bin and a current range associated with a current state of the context-adaptive arithmetic encoding or decoding; deriving an LPS probability index corresponding to an inverted current binarized probability value or the current binarized probability value, depending on whether the current binarized probability value of the current bin is greater than or equal to 2k?1, k being a positive integer; deriving a range index for identifying one range interval containing the current range; and deriving an LPS range using one or more mathematical operations.

Abstract: A method and apparatus of video coding are disclosed. A piece-wise linear mapping is derived to map a target luma sample from a first signal domain to a second signal domain, or vice versa. The piece-wise linear mapping process comprises determining first pivot points for performing video encoding or decoding of the luma samples using a piece-wise linear mapping. The first pivot points are determined so that: if a target mapped pivot point corresponding to one first pivot point in the second signal domain has a multiple of the target interval value, the target mapped pivot point and a next mapped pivot point can be located in a same second segment; and otherwise, the target mapped pivot point and the next mapped pivot point cannot be located in the same second segment.

Abstract: Method and apparatus for constrained de-blocking filter are disclosed. One method receives input data related to a current block in a current picture at a video encoder side or a video bitstream corresponding to compressed data including the current block in the current picture at a video decoder side, and determines a first boundary associated with the current block, wherein the first boundary corresponds to one vertical boundary or one horizontal boundary of the current block. The method then applies de-blocking process to a reconstructed current block corresponding to the current block to result in a filtered-reconstructed current block, using a plurality of first reference samples at a same side of the first boundary, and replaces a first set of the first reference samples by one or more padding values. The method then generates a filtered decoded picture including the filtered-reconstructed current block.

Abstract: An intra prediction method comprises receiving input data of a current block in a current picture, deriving reference samples of the current block from boundary samples, selecting a matrix for the current block, generating intermediate predicted samples by multiplying the reference samples and the matrix, and clipping the intermediate predicted samples before up-sampling. The intra prediction method further comprises performing an up-sampling process on the clipped intermediate predicted samples to generate predicted samples for the current block, and encoding or decoding the current block according to the predicted samples of the current block.