Tencent America LLC

Yixin Du

Shan Liu

Xin Zhao

Liang Zhao

Xiang Yang Li

Xiang Li

Stephan Wenger

Byeongdoo Choi

Madhu Peringassery Krishnan

Xiaozhong Xu

Guichun Li

Sehoon Yea

A method for in-loop sample offset filtering in a video decoder is disclosed. The method includes obtaining at least one statistical property associated with reconstructed samples of at least a first color component in a current reconstructed data block of a video stream, selecting a target sample offset filter among a plurality of sample offset filters based on the at least one statistical property, the target sample offset filter comprising a nonlinear mapping between sample delta measures and sample offset values, and filtering a current sample in a second color component of the current reconstructed data block using the target sample offset filter and reference samples in a third color component of the current reconstructed data block to generate a filtered reconstructed sample of the current sample.

Adaptive non-linear mapping for sample offset

In a method for filtering in video decoding, a coded video bitstream that includes filter shape index information is received. A filter shape configuration of a video filter is determined based on the filter shape index information. The filter shape index information indicates that a number of filter taps of the filter shape configuration is less than five. Offset values associated with the filter shape configuration of the video filter are determined. The video filter is applied on a sample based on the offset values associated with the filter shape configuration.

Filter shape for sample offset

Systems and methods may provide flexible picture partitioning, a method includes receiving a bitstream, that includes a picture, the picture partitioned into a plurality of coding tree units (CTUs), wherein at least one row or column of CTUs, among the plurality of CTUs of the picture, that is adjacent to a boundary of the picture has a size dimension that is smaller than a corresponding size dimension of each CTU among the plurality of CTUs that is not adjacent to any boundary of the picture; and encoding the bitstream based on the plurality of CTUs, wherein the at least one row or column of CTUs includes a first CTU row or a first CTU column of the picture that is adjacent to a top boundary or left boundary of the picture, respectively.

Flexible picture partitioning

Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus includes processing circuitry. For example, the processing circuitry obtains reconstructed samples in a temporal source frame that is different from a current frame, and determines filter coefficients of a filter for a current block in the current frame based on at least the reconstructed samples in the temporal source frame. The processing circuitry generates prediction information of the current block based on the determined filter coefficients. The temporal source frame is an inter coded frame that satisfies at least one of a quantization parameter (QP) requirement, a temporal distance requirement, and a reference picture requirement.

Cross component filtering using a temporal source frame

A method for video encoding includes determining a filter shape of a cross-component filter applied to a chroma coding block (CB), generating a first intermediate CB by applying a loop filter to the chroma CB, and generating a second intermediate CB by applying, to a corresponding luma CB, the cross-component filter applied to the chroma CB and having the determined filter shape. The method further includes determining a filtered chroma CB based on the first intermediate CB and the second intermediate CB by combining the loop filtered chroma CB with the cross-component filtered luma CB, and generating coded information of the chroma CB in a coded video bitstream. Determining the filter shape includes determining the filter shape of the cross-component filter based on the number of the filter coefficients and based on at least one of (i) the chroma subsampling format or (ii) the chroma sample type.

Selecting a filter shape of a cross-component filter

Aspects of the disclosure include methods, apparatuses, and non-transitory computer-readable storage mediums for video encoding/decoding. An apparatus includes processing circuitry that determines reconstructed samples of a first color component in a filter support region of a current picture that is a part of a coded video sequence. The processing circuitry performs a filter process on the reconstructed samples of the first color component in the filter support region. A quantization step size of the filter process is separately set per one of a coding block, a video frame, and a video sequence. The processing circuitry reconstructs samples of a second color component in the filter support region based on an output value of the filter process. The second color component is different from the first color component.

Adaptive quantization step size in CCSO filtering

An apparatus includes processing circuitry that decodes prediction information of a current block in a current picture that is a part of a coded video sequence. The processing circuitry determines whether a cross component filtering (CCF) process is enabled for the current block based on one of a partitioning scheme, a prediction mode, a block width, a block height, transform coefficients, and quantization parameters. The processing circuitry generates filtered reconstruction samples of the current block by applying the CCF process on at least one of predicted samples, residual values, or reconstruction samples of the current block based on the CCF process being enabled. The filtered reconstruction samples of the current block are used for reconstruction of a subsequent block. The processing circuitry reconstructs the current block and the subsequent block based on the filtered reconstruction samples of the current block.

Cross-component filtering on block-level reconstruction

Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus for video encoding includes processing circuitry. The processing circuitry determines a coding tree unit (CTU) size for a plurality of pictures. The processing circuitry generates CTU size information based on the determined CTU size. The processing circuitry encodes the plurality of pictures based on the determined CTU size. The CTU size information includes a first bit that is a first value based on the CTU size being determined as a first CTU size. The CTU size information includes the first bit that is a second value and a second bit based on the CTU size being determined as one of a second CTU size and a third CTU size. The CTU size information includes the second bit based on the first bit being the second value.

Signaling of CTU size

A method of video coding, executable by a processor, includes receiving video data having a coding tree unit size, determining whether the coding tree unit size is greater than a predetermined threshold, and in response to the coding tree unit size being greater than the predetermined threshold, signaling, in a sequence parameter set (SPS), a first flag indicating whether a maximum transform size in luma samples is equal to 64. The first flag being equal to 1 specifies that the maximum transform size in luma samples is equal to 64, the first flag equal to 0 specifies that the maximum transform size in luma samples is equal to 32, and when not present, the first flag is inferred to be equal to 0.

Video coding transform size signaling

A method of video decoding includes decoding prediction information of a current block indicating a subset of combinations of processed reconstructed samples of a first component and corresponding offset values of a filter process to be applied to a second color component, and determining an offset value of the filter process to apply to reconstructed samples of the second color component based on a combination of processed reconstructed samples of the first component. The determined offset value is based on whether the combination of the processed reconstructed samples of the first color component corresponds to or is different from the combinations of the processed reconstructed samples.

Filter offset value mapping

A method, a non-transitory computer readable medium, and a computer system is provided for encoding or decoding video data. The method may include: receiving video data comprising a chroma component and a luma component; parsing, deriving or selecting a number of presets for the chroma component in one frame, and a number of presets for the luma component in the one frame; and decoding the video data. The method may further comprise: performing a separate Constrained Directional Enhancement Filter (CDEF) process of filtering luma and chroma components independent from each other based on the number of presets for the chroma component in one frame, and the number of presets for the luma component in the one frame.

Separate constrained directional enhancement filter

Aspects of the disclosure provide a method and an apparatus including processing circuitry for video decoding. The processing circuitry can decode coded information of a coding block in a picture of a coded video sequence. The coded information indicates a clipping index m. The clipping index m indicates a clipping value for a filter that is applied to the coding block. The processing circuitry can determine the clipping value associated with the clipping index m. The clipping value can be dependent on a bit depth B and the clipping index m. The clipping value for each value of the clipping index m can be independent from N. N is a total number of allowed clipping values that include the clipping value. The processing circuitry generates a filtered coding block by applying the filter corresponding to the clipping value to the coding block.

Method and apparatus for non-linear loop filtering

A method for filtering in video encoding is provided. In the method, based on a determination that (i) an intra block copy (IBC) mode is disabled for a chroma component of a block and the IBC mode is enabled for a luma component of the block or (ii) decoupled partitioning structures are applied to the luma component of the block and the chroma component of the block, at least one loop filter is enabled for the chroma component of the block, a first sample of the luma component at a location in the block is determined based on a first loop filter configuration that does not include the at least one loop filter, and a second sample of the chroma component at the location in the block is determined based on a second loop filter configuration that includes the at least one loop filter.

Method and apparatus for video filtering

Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus for filtering in video decoding includes processing circuitry. For example, the processing circuitry determines first reconstructed sample values of reconstructed samples of a first color component within a filter support region of a to-be filtered sample of a second color component. The to-be filtered sample is at a center position of the filter support region. Based on a mapping that associates offset values with reconstructed sample values within the filter support region, a first offset value of the offset values in the mapping that is associated with the first reconstructed sample values is determined. The first offset value is applied on the second color component for the to-be filtered sample to determine a filtered sample value of the second color component for the to-be filtered sample.

Method and apparatus for offset in video filtering

A method, computer program, and computer system is provided for coding video data. Reference samples and magnitudes of transform coefficients corresponding to a current block of video data from an input to a neural network are identified. Sign values associated with the transform coefficients are predicted using neural networks. The video data is encoded/decoded based on the predicted sign values.

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Los Altos, CA, United States of America

Yixin Du