Method and apparatus for palette coding with cross block prediction

    公开(公告)号:US10182242B2

    公开(公告)日:2019-01-15

    申请号:US15101139

    申请日:2014-12-26

    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.

    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.

    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.

    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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