A method for a video coding system using coding modes including an Inter prediction mode and an Intra Block Copy, IntraBC, mode, comprising: determining a variable to indicate whether two versions of a reconstructed current image unit are needed; if the variable indicates that two versions of the reconstructed current image unit are needed, allowing a loop-filtered version of the reconstructed current image unit and a non-loop-filter version of the reconstructed current image unit to be stored and used as reference data; and if the variable indicates that two versions of the reconstructed current image unit are not needed, storing only one version of the reconstructed current image unit as the reference data; characterized in that the variable is determined based on one or more syntax elements in a picture level of a bitstream, wherein said one or more syntax elements are selected from a group of syntax elements comprising a first syntax element indicating whether the IntraBC mode is enabled for a current picture, a second syntax element indicating whether Sample Adaptive Offset, SAO, is enabled, a third syntax element indicating whether deblocking-filter is disabled, and a fourth syntax element indicating whether deblocking-filter-override is enabled; wherein the variable is determined to allow said two versions of the reconstructed current image unit to be stored if the first syntax element indicates that the IntraBC mode is enabled for a current picture and any of three conditions is true, wherein the three conditions correspond to the second syntax element indicates that the SAO is enabled, the third syntax element indicates that the deblocking-filter is not disabled, and the fourth syntax element indicates that the deblocking-filter-override is enabled. determining a variable to indicate whether two versions of a reconstructed current image unit are needed; if the variable indicates that two versions of the reconstructed current image unit are needed, allowing a loop-filtered version of the reconstructed current image unit and a non-loop-filter version of the reconstructed current image unit to be stored and used as reference data; and if the variable indicates that two versions of the reconstructed current image unit are not needed, storing only one version of the reconstructed current image unit as the reference data; characterized in that the variable is determined based on one or more syntax elements in a picture level of a bitstream, wherein said one or more syntax elements are selected from a group of syntax elements comprising a first syntax element indicating whether the IntraBC mode is enabled for a current picture, a second syntax element indicating whether Sample Adaptive Offset, SAO, is enabled, a third syntax element indicating whether deblocking-filter is disabled, and a fourth syntax element indicating whether deblocking-filter-override is enabled; wherein the variable is determined to allow said two versions of the reconstructed current image unit to be stored if the first syntax element indicates that the IntraBC mode is enabled for a current picture and any of three conditions is true, wherein the three conditions correspond to the second syntax element indicates that the SAO is enabled, the third syntax element indicates that the deblocking-filter is not disabled, and the fourth syntax element indicates that the deblocking-filter-override is enabled.