Chroma intra prediction method and device

A chroma intra prediction method, applied to an encoder, the method comprising:

• determining a direct mode (DM) corresponding to a current chroma block;
• determining an intra prediction mode of the current chroma block from a set of chroma prediction modes, wherein the set of chroma prediction modes comprises at least one of the DM, linear mode (LM), LM_T or LM_L, wherein when a luma prediction mode corresponding to the DM is a direct current (DC) mode or a planar mode, the set of chroma prediction modes comprises a diagonal angular mode with prediction direction index number 66, wherein the linear mode is acquired from a bitstream before determining the set of chroma prediction modes;
• and
• determining a reconstructed value of the current chroma block according to the intra prediction mode.

A chroma intra prediction device, applied to a decoder, the device comprising:

• a processor and a memory storing instructions executable by the processor, wherein the processor is configured to execute the instructions to perform operations of:
• determining a direct mode (DM) corresponding to a current chroma block;
• determining an intra prediction mode of the current chroma block from a set of chroma prediction modes, wherein the set of chroma prediction modes comprises at least one of the DM, linear mode (LM), LM_T or LM_L, wherein when a luma prediction mode corresponding to the DM is a direct current (DC) mode or a planar mode, the set of chroma prediction modes comprises a diagonal angular mode with prediction direction index number 66, wherein the linear mode is acquired from a bitstream before determining the set of chroma prediction modes;
• and
• determining a reconstructed value of the current chroma block according to the intra prediction mode.

A chroma intra prediction device, applied to an encoder, the device comprising:

• a processor and a memory storing instructions executable by the processor, wherein the processor is configured to execute the instructions to perform operations of:
• determining a direct mode (DM) corresponding to a current chroma block;
• determining an intra prediction mode of the current chroma block from a set of chroma prediction modes, wherein the set of chroma prediction modes comprises at least one of the DM, linear mode (LM), LM_T or LM_L, wherein when a luma prediction mode corresponding to the DM is a direct current (DC) mode or a planar mode, the set of chroma prediction modes comprises a diagonal angular mode with prediction direction index number 66, wherein the linear mode is acquired from a bitstream before determining the set of chroma prediction modes;
• and
• determining a reconstructed value of the current chroma block according to the intra prediction mode.