Signaling Quantization Matrix
    141.
    发明申请

    公开(公告)号:US20210092361A1

    公开(公告)日:2021-03-25

    申请号:US17029239

    申请日:2020-09-23

    Applicant: MediaTek Inc.

    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.

    Method of block vector clipping and coding for screen content coding and video coding

    公开(公告)号:US10856009B2

    公开(公告)日:2020-12-01

    申请号:US15514926

    申请日:2015-10-08

    Applicant: MEDIATEK INC.

    Abstract: A method of video coding using coding modes including IntraBC mode (Intra-block copy mode) for a picture is disclosed. The system determines whether the current reference block is located above a current coding unit (CU) containing the current prediction unit (PU) in a vertical direction and whether the current reference block is located on a left side of the current CU in a horizontal direction based on the original block vector (BV). If both results are not true, the original BV is clipped to a clipped BV so that a relocated reference block corresponding to the clipped BV is above the current CU in the vertical direction or to the left side of the current CU in the horizontal direction. The clipped BV is used as a predictor for encoding or decoding of a current BV or used for IntraBC encoding or decoding of the current PU.

    Signaling Of Motion Vector Difference Derivation

    公开(公告)号:US20200374551A1

    公开(公告)日:2020-11-26

    申请号:US16880344

    申请日:2020-05-21

    Applicant: MediaTek Inc.

    Abstract: A video decoder receives data for a block of pixels to be decoded as a current block of a current picture of a video. When the current block is coded by using inter mode and bi-directional prediction, the video decoder receives a first motion vector difference and determines a second motion vector difference based on a first flag or a second flag. When the first flag is false, the video decoder uses the second flag to determine whether to set the second motion vector difference to be at an opposite value of the first motion vector difference. When the first flag is true, the video decoder sets the second motion vector difference to be zero. The video decoder reconstructs the current block by using motion information based on the first motion vector difference and the second motion vector difference to perform inter prediction.

    Adaptive Loop Filter With Adaptive Parameter Set

    公开(公告)号:US20200329239A1

    公开(公告)日:2020-10-15

    申请号:US16845070

    申请日:2020-04-10

    Applicant: MediaTek Inc.

    Abstract: A method for signaling adaptive loop filter (ALF) settings is provided. A video decoder receives data from a bitstream for a block of pixels to be decoded as a current block of a current picture of a video. The video decoder parses whether to use adaptive parameter set (APS) for filtering the current block without determining whether to select a particular APS from a plurality of APSs. When the APS is used to filter the current block, the video decoder parses a first filter selection index for selecting a filter from a set of filters in the APS. When the APS is not used to filter the current block, the video decoder signals a second filter selection index for selecting a filter from a set of default fixed filters. The video decoder filters the current block based on the selected filter. The video decoder outputs the filtered current block.

    Shared Candidate List
    145.
    发明申请

    公开(公告)号:US20200059659A1

    公开(公告)日:2020-02-20

    申请号:US16541627

    申请日:2019-08-15

    Applicant: MediaTek Inc.

    Abstract: A video coder that uses a shared candidate list to encode or decode multiple blocks of pixels within a shared boundary is provided. The video coder identifies a shared boundary encompassing a plurality of blocks of pixels of a current picture in a video sequence. The video coder identifies one or more prediction candidates as a shared candidate list based on neighbors of a region defined by the shared boundary. The video coder codes one or more blocks of pixels encompassed by the shared boundary by using one or more prediction candidates selected from the shared candidate list.

    Method and apparatus for palette coding with cross block prediction

    公开(公告)号:US10531119B2

    公开(公告)日:2020-01-07

    申请号:US16203994

    申请日:2018-11-29

    Applicant: MediaTek Inc.

    Abstract: A method and apparatus for color index coding of a block of video data using index prediction based on reconstructed neighboring pixels are disclosed. In one embodiment, color index encoding or decoding is applied to the current pixel indices by deriving index prediction from neighboring pixel indices of the reconstructed neighboring pixels. The reconstructed neighboring pixel values are first transformed into the neighboring pixel indices according to a quantization table to map between major color indices and major color values of the current block. The quantization table can be based on a major color table for the current block or can also be derived at a decoder side. The decoding process may reconstruct the current pixels by converting decoded current pixel indices to reconstructed current pixel values according to the quantization table or by directly copying the reconstructed neighboring pixel values indicated by decoded current pixel indices.

    Storage Of Motion Vectors For Affine Prediction

    公开(公告)号:US20190327482A1

    公开(公告)日:2019-10-24

    申请号:US16392040

    申请日:2019-04-23

    Applicant: MediaTek Inc.

    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.

    Method and apparatus of palette index map coding for screen content coding

    公开(公告)号:US10356427B2

    公开(公告)日:2019-07-16

    申请号:US15764346

    申请日:2016-09-30

    Applicant: MEDIATEK INC.

    Abstract: A method and apparatus for video coding using coding modes including a palette mode are disclosed. In one embodiment, the total number of palette indices in the current block is coded into a binary string using a TR (Truncated Rice) binarization process with the Rice parameter to generate a prefix part and using an EGk (k-th order Exp-Golomb) binary process to generate a suffix part for the binary string, or using the EGk binarization process with the Rice parameter (k). The suffix part is allowed to be empty. In another embodiment, a Rice parameter is determined. If the Rice parameter is equal to or greater than log-base-2 of current block size, the variable related to a total number of palette indices in the current block of video data is binarized into a binary string using a fixed-length code with bit length equal to log-base-2 of current block size.

    Method and apparatus for palette index coding in video and image compression

    公开(公告)号:US10205968B2

    公开(公告)日:2019-02-12

    申请号:US15545381

    申请日:2016-02-03

    Applicant: MEDIATEK INC.

    Abstract: A method of palette index map coding of blocks in a picture by grouping coded symbols of the same type is disclosed for video encoder and decoder. In one embodiment, all syntax elements corresponding to the pixel index are grouped into a pixel index group, and all syntax elements corresponding to the escape pixel are grouped into an escape pixel group. All syntax elements corresponding to the run type and run length are grouped into an interleaved run type/run length group, or grouped into separate run type group and run length group. In another embodiment, the system parses from the video bitstream a last-run mode syntax element for a current block, where the last-run mode syntax element indicates whether a last run mode is a copy-index mode or a copy-above mode. Information associated with the last-run mode syntax element is used for reconstructing palette index map.

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