A method for processing information, applied to a video decoder, comprising: decoding a bitstream, obtaining a prediction mode, predicting a colour component of a coding block according to the prediction mode to obtain a third prediction block, wherein the prediction mode is preset and is a Position-Dependent Prediction Combination, PDPC, mode, wherein, the colour component is a luma component or a chroma component; wherein, the colour component of the coding block is predicted according to the prediction mode to obtain the third prediction block, only when the following cases 1 to 4 are all met: in case 1, when the coding block is a luma block, and an Intra Sub-Partitions is not used; or, the coding block is a chroma block; in case 2, when the coding block is a luma block, and a 0th reference line is used for prediction; or, the coding block is a chroma block; wherein the 0th reference line refers to a reference line closest to the coding block; in case 3, the coding block is not coded by using a Block-based Delta Pulse Code Modulation, BDPCM; in case 4, any of following conditions is met: the prediction mode is a horizontal prediction mode; the prediction mode is a vertical prediction mode; the prediction mode is a prediction mode with an index being a first numerical value among the N preset spatial prediction modes within a component; the prediction mode is a prediction mode with the index being a fourth numerical value; the prediction mode is a prediction mode with the index smaller than or equal to a second numerical value, and the coding block is not a chroma block; or, the prediction mode is a prediction mode with the index greater than or equal to a third numerical value, and the coding block is not a chroma block; refining the third prediction block according to the prediction mode to obtain a third refinement block; and obtaining a sum of a residual block included in the bitstream and the third refinement block to obtain a reconstructed block, processing the reconstructed block, and outputting processed video data. decoding a bitstream, obtaining a prediction mode, predicting a colour component of a coding block according to the prediction mode to obtain a third prediction block, wherein the prediction mode is preset and is a Position-Dependent Prediction Combination, PDPC, mode, wherein, the colour component is a luma component or a chroma component; wherein, the colour component of the coding block is predicted according to the prediction mode to obtain the third prediction block, only when the following cases 1 to 4 are all met: in case 1, when the coding block is a luma block, and an Intra Sub-Partitions is not used; or, the coding block is a chroma block; in case 2, when the coding block is a luma block, and a 0th reference line is used for prediction; or, the coding block is a chroma block; wherein the 0th reference line refers to a reference line closest to the coding block; in case 3, the coding block is not coded by using a Block-based Delta Pulse Code Modulation, BDPCM; in case 4, any of following conditions is met: the prediction mode is a horizontal prediction mode; the prediction mode is a vertical prediction mode; the prediction mode is a prediction mode with an index being a first numerical value among the N preset spatial prediction modes within a component; the prediction mode is a prediction mode with the index being a fourth numerical value; the prediction mode is a prediction mode with the index smaller than or equal to a second numerical value, and the coding block is not a chroma block; or, the prediction mode is a prediction mode with the index greater than or equal to a third numerical value, and the coding block is not a chroma block; in case 1, when the coding block is a luma block, and an Intra Sub-Partitions is not used; or, the coding block is a chroma block; in case 2, when the coding block is a luma block, and a 0th reference line is used for prediction; or, the coding block is a chroma block; wherein the 0th reference line refers to a reference line closest to the coding block; in case 3, the coding block is not coded by using a Block-based Delta Pulse Code Modulation, BDPCM; in case 4, any of following conditions is met: the prediction mode is a horizontal prediction mode; the prediction mode is a vertical prediction mode; the prediction mode is a prediction mode with an index being a first numerical value among the N preset spatial prediction modes within a component; the prediction mode is a prediction mode with the index being a fourth numerical value; the prediction mode is a prediction mode with the index smaller than or equal to a second numerical value, and the coding block is not a chroma block; or, the prediction mode is a prediction mode with the index greater than or equal to a third numerical value, and the coding block is not a chroma block; refining the third prediction block according to the prediction mode to obtain a third refinement block; and obtaining a sum of a residual block included in the bitstream and the third refinement block to obtain a reconstructed block, processing the reconstructed block, and outputting processed video data.