CODER, DECODER AND CORRESPONDING METHODS RELATED TO INTRA-FRAME PREDICTION MODE Russian patent published in 2023 - IPC H04N19/186 

FIELD: image processing.

SUBSTANCE: invention relates to performing an intraframe chrominance prediction mode derivation using the intra-frame prediction mode from a corresponding luminance component. The technical result is to increase the compression ratio with minimal or no effect on image quality. The result is achieved in that the encoding implemented by the decoding device or the encoding device comprises obtaining indication information for the position (cbWidth/2, cbHeight/2) of the brightness of the current encoding block relative to the top-left position (xCb, yCb) of the brightness sample of the current encoding block, in wherein cbWidth represents the width of the current coding block in luma samples, cbHeight represents the height of the current coding block in luma samples; setting the value of the luminance intraframe prediction mode associated with the current coding block as the first default value when the indication information indicates that the matrix-based Intra Prediction (MIP) mode is applied to the luminance samples at the position (cbWidth/2, cbHeight/2) brightness relative to the upper left position (xCb, yCb) of the brightness sample of the current coding block; and deriving an intra chroma prediction mode value based on the intra chroma prediction mode value of the current coding block.

EFFECT: increased compression ratio with minimal or no effect on image quality.

30 cl, 13 dwg, 4 tbl