Method of efficient signalling of CBF flags

    公开(公告)号:US11375213B2

    公开(公告)日:2022-06-28

    申请号:US17368502

    申请日:2021-07-06

    Abstract: A method of coding implemented by a decoding device or encoding device, the method comprising obtaining a bitstream, the bitstream comprises a transform unit syntax; the syntax comprises at least two cbf flags for chroma blocks (in an example, transform unit syntax correspond to either transform unit or sub-transform units which include two chroma cbf flags: tu_cbf_cb and tu_cbf_cb—one flag for each chroma plane), a chroma cbf flag specifies whether certain block has residue in correspondent color plane; deriving a value of a luma cbf flag tu_cbf_luma based on one or any combination of a value of a cu_cbf flag, values of two chroma cbf flags corresponding to a current transform unit or sub-transform unit, location of the sub-transform unit within transform unit, values of luma and chroma cbf flags correspondent to previous sub-transform units in the current transform unit.

    Performing chroma deblocking for blocks which use joint chroma coding

    公开(公告)号:US12238289B2

    公开(公告)日:2025-02-25

    申请号:US18349988

    申请日:2023-07-11

    Abstract: A method for deblocking a chroma block edge between a first chroma block of a first image block and a second chroma block of a second image block. The method includes a decision process which includes: determining a first chroma quantization parameter for the first chroma block based on a first luma quantization parameter of a first luma block of the first image block and a chroma QP mapping table for the first chroma block; determining a second chroma quantization parameter for the second chroma block based on a second luma quantization parameter of a second luma block of the second image block and a chroma QP mapping table for the second chroma block; determining an averaged and rounded chroma quantization parameter based on the first chroma quantization parameter and the second chroma quantization parameter; and determining a threshold parameter based on the averaged and rounded chroma quantization parameter.

    Method and apparatus for signalling flags related to chroma transform blocks

    公开(公告)号:US12143607B2

    公开(公告)日:2024-11-12

    申请号:US18206770

    申请日:2023-06-07

    Abstract: A method comprising obtaining a bitstream, the bitstream comprises a transform unit syntax and a coding unit syntax, the transform unit syntax includes a value of a first flag and a value of a second flag related to, respectively, a first chroma transform block and a second chroma transform block of a current transform unit or a current sub-transform unit within the current transform unit, the first or second flag specifies whether the first or second chroma transform block contains at least one transform coefficient levels not equal to 0, the coding unit syntax includes a value of a third flag specifying whether a transform tree structure is present or not; and deriving a value of a fourth flag based on the values of the first, second, and third flags, the fourth flag specifies whether a luma transform block contains at least one transform coefficient levels not equal to 0.

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