INTRA BLOCK COPY-BASED ENCODING/DECODING METHOD AND DEVICE, AND BITSTREAM STORAGE MEDIUM

1 . A method of decoding an image, the method comprising:

obtaining prediction mode information of a current block from a bitstream, the prediction mode information indicating whether an intra block copy mode is applied to the current block or not;

determining, based on the prediction mode information, whether a prediction mode of the current block is the intra block copy mode;

determining whether to decode a coded block flag of the current block based on the prediction mode of the current block, the coded block flag indicating whether residual signal of a transform block for the current block is present in the bitstream or not,

wherein in response to the current block being a dual tree luma block and the prediction mode of the current block being the intra block copy mode, decoding the coded block flag from the bitstream is omitted, and

wherein in response to decoding the coded block flag being omitted, a value of the coded block flag is inferred to indicate that the residual signal of the transform block for the current block is present; and

obtaining residual samples based on the residual signal for the transform block of the current block.

2 . The method of claim 1 , wherein in response to the current block being chroma block under the dual tree structure, the prediction mode information is not decoded from the bitstream, and a value of the prediction mode information is implicitly determined at a decoder side.

3 . A method of encoding an image, the method comprising:

obtaining prediction samples of a current block according to a prediction mode of the current block;

encoding prediction mode information of the current block into a bitstream, the prediction mode information indicating whether the prediction mode of the current block is an intra block copy mode or not;

obtaining residual samples of the current block based on the prediction sample;

obtaining residual signal based on the residual samples of the current block; and

determining whether to encode a coded block flag of the current block based on the prediction mode of the current block, the coded block flag indicating whether the residual signal of a transform block for the current block is present in the bitstream or not,

wherein in response to the current block being a dual tree luma block and the prediction mode of the current block being the intra block copy mode, encoding the coded block flag into the bitstream is omitted, and

wherein the residual signal of the current block is encoded into the bitstream even though encoding the coded block flag being omitted.

4 . A non-transitory computer-readable recording medium storing a bitstream that is generated by a method of encoding an image, the method comprising:

obtaining prediction samples of a current block according to a prediction mode of the current block;

encoding prediction mode information of the current block into a bitstream, the prediction mode information indicating whether the prediction mode of the current block is an intra block copy mode or not;

obtaining residual samples of the current block based on the prediction sample;

obtaining residual signal based on the residual samples of the current block; and

determining whether to encode a coded block flag of the current block based on the prediction mode of the current block, the coded block flag indicating whether the residual signal of a transform block for the current block is present in the bitstream or not,

wherein in response to the current block being a dual tree luma block and the prediction mode of the current block being the intra block copy mode, encoding the coded block flag into the bitstream is omitted, and

wherein the residual signal of the current block is encoded into the bitstream even though encoding the coded block flag being omitted.