A method for video decoding in a decoder, comprising: storing reconstructed samples of a reconstructed block of a picture in a memory, the reconstructed samples of the reconstructed block being reconstructed according to a Versatile Video Coding, VVC, encoded video bitstream; and when a current sub-block in a current block of the picture is to be reconstructed using intra block copy, IBC, based on a reference sub-block in the reconstructed block, wherein the current block having a size of 128×128 luma samples includes at least four non-overlapping partitions, including a current partition in which the current sub-block is located, and the at least four non-overlapping partitions each having a maximum size of 64×64 luma sample s, the reconstructed block having a size of 128×128 luma samples includes at least four non-overlapping partitions that are collocated with the at least four partitions of the current block respectively, determining whether the reconstructed samples of the reference sub-block stored in the memory are indicated as overwritten based on a position of the current sub-block, generating reconstructed samples of the current sub-block for output based on the reconstructed samples of the reference sub-block when the reconstructed samples of the reference sub-block stored in the memory are determined to be indicated as not overwritten, and overwriting the reconstructed samples of a collocated sub-block in the reconstructed block stored in the memory with the generated reconstructed samples of the current sub-block, generating the reconstructed samples of the current sub-block without using the reference sub-block when the reconstructed samples of the reference sub-block stored in the memory are determined to be indicated as overwritten. storing reconstructed samples of a reconstructed block of a picture in a memory, the reconstructed samples of the reconstructed block being reconstructed according to a Versatile Video Coding, VVC, encoded video bitstream; and when a current sub-block in a current block of the picture is to be reconstructed using intra block copy, IBC, based on a reference sub-block in the reconstructed block, wherein the current block having a size of 128×128 luma samples includes at least four non-overlapping partitions, including a current partition in which the current sub-block is located, and the at least four non-overlapping partitions each having a maximum size of 64×64 luma sample s, the reconstructed block having a size of 128×128 luma samples includes at least four non-overlapping partitions that are collocated with the at least four partitions of the current block respectively, determining whether the reconstructed samples of the reference sub-block stored in the memory are indicated as overwritten based on a position of the current sub-block, generating reconstructed samples of the current sub-block for output based on the reconstructed samples of the reference sub-block when the reconstructed samples of the reference sub-block stored in the memory are determined to be indicated as not overwritten, and overwriting the reconstructed samples of a collocated sub-block in the reconstructed block stored in the memory with the generated reconstructed samples of the current sub-block, generating the reconstructed samples of the current sub-block without using the reference sub-block when the reconstructed samples of the reference sub-block stored in the memory are determined to be indicated as overwritten. determining whether the reconstructed samples of the reference sub-block stored in the memory are indicated as overwritten based on a position of the current sub-block, generating reconstructed samples of the current sub-block for output based on the reconstructed samples of the reference sub-block when the reconstructed samples of the reference sub-block stored in the memory are determined to be indicated as not overwritten, and overwriting the reconstructed samples of a collocated sub-block in the reconstructed block stored in the memory with the generated reconstructed samples of the current sub-block, generating the reconstructed samples of the current sub-block without using the reference sub-block when the reconstructed samples of the reference sub-block stored in the memory are determined to be indicated as overwritten.