Method for picture decoding, method for picture encoding, decoder, and encoder

A method for picture encoding, comprising:

• acquiring a current picture;
• disabling a cross-encoding function when an encoding manner for the current picture is determined to be independent encoding of colour components, wherein the cross-encoding function allows encoding based on a dependency relationship between two chroma components;
• encoding a flag indicating the encoding manner into a bitstream corresponding to the current picture;
• and
• enabling the cross-encoding function when the encoding manner for the current picture is determined to be cross-encoding of colour components;
• and
• after enabling the cross-encoding function when the encoding manner for the current picture is determined to be cross-encoding of colour components,
• encoding the flag in a direct mode (DM).

A decoder, comprising:

• at least one processor;
• and
• a memory, coupled to the at least one processor and storing at least one computer executable instruction which, when executed by the at least one processor, causes the at least one processor to:
• acquire a bitstream corresponding to a current picture;
• parse the bitstream to obtain a flag corresponding to the current picture;
• disable a cross-decoding function when a decoding manner indicated by the flag is independent decoding of colour components, wherein the cross-decoding function allows decoding based on a dependency relationship between two chroma components;
• enable the cross-decoding function when the decoding manner indicated by the flag is cross-decoding of colour components;
• and
• decode the current picture in a direct mode (DM).

An encoder, comprising:

• at least one processor;
• and
• a memory, coupled to the at least one processor and storing at least one computer executable instruction thereon which, when executed by the at least one processor, causes the at least one processor to:
• acquire a current picture;
• disable a cross-encoding function when an encoding manner for the current picture is determined to be independent encoding of colour components, wherein the cross-encoding function allows encoding based on a dependency relationship between two chroma components;
• encode a flag indicating the encoding manner into a bitstream corresponding to the current picture;
• enable the cross-encoding function when the encoding manner is determined to be cross-encoding of colour components;
• and
• encode the flag in a direct mode (DM).