Encoder, encoding method, decoder, and decoding method

    公开(公告)号:US12096005B2

    公开(公告)日:2024-09-17

    申请号:US18376618

    申请日:2023-10-04

    CPC classification number: H04N19/159 H04N19/176 H04N19/61 H04N19/625

    Abstract: An encoder which encodes a current block of a picture includes a processor and memory. Using the memory, the processor: determines whether intra prediction is to be used for the current block; and when it is determined that intra prediction is to be used for the current block, generates first transform coefficients by performing first transform of residual signals of the current block using a first transform basis; quantizes the first transform coefficients when an intra prediction mode for the current block is a determined mode and the first transform basis is different from a determined transform basis; and generates second transform coefficients by performing second transform of the first transform coefficients using a second transform basis, and quantizes the second transform coefficients, when the intra prediction mode for the current block is not the determined mode or when the first transform basis matches the determined transform basis.

    Encoder, decoder, encoding method, and decoding method

    公开(公告)号:US12075052B2

    公开(公告)日:2024-08-27

    申请号:US17499294

    申请日:2021-10-12

    CPC classification number: H04N19/126 H04N19/159 H04N19/176 H04N19/61

    Abstract: Provided is an encoder including: circuitry; and memory coupled to the circuitry, in which the circuitry: derives a prediction residual indicating a difference between a current block and a prediction image of the current block; performs primary transform on the prediction residual, and performs secondary transform on a result of the primary transform; performs quantization on a result of the secondary transform; and encodes a result of the quantization. In the performing of the secondary transform, when a matrix weighted intra prediction included in intra prediction and having prediction modes is used, the circuitry uses, as a transform set for the secondary transform, a common transform set shared among the prediction modes. The matrix weighted intra prediction generates the prediction image by performing matrix calculation on a pixel sequence obtained from pixel values of surrounding pixels of the current block.

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