Method for chroma component prediction based on reconstructed luma information

A method performed by a video encoding device for intra-predicting a current chroma block, the method comprising:

• generating a first prediction block of the current chroma block by using a Direct Mode_Intra Block Copy mode (DM_IBC mode) that uses a block vector of a previously reconstructed corresponding luma block to generate the first prediction block;
• generating a second prediction block of the current chroma block by using a chroma prediction mode that is a prediction mode for a chroma component;
• determining a prediction mode indicator of the current chroma block based on the first prediction block and the second prediction block in terms of rate-distortion optimization, the prediction mode indicator indicating whether the DM_IBC mode is to be used for the current chroma block;
• and
• encoding the prediction mode indicator.

A computer-readable recording medium storing a bitstream generated by a video encoding method, the video encoding method comprising:

• generating a first prediction block of a current chroma block by using a Direct Mode_Intra Block Copy mode (DM_IBC mode) that uses a block vector of a previously reconstructed corresponding luma block to generate the first prediction block;
• generating a second prediction block of the current chroma block by using a chroma prediction mode that is a prediction mode for a chroma component;
• determining a prediction mode indicator of the current chroma block based on the first prediction block and the second prediction block in terms of rate-distortion optimization, the prediction mode indicator indicating whether the DM_IBC mode is to be used for the current chroma block;
• and
• encoding the prediction mode indicator.