In a computing device that implements a video encoder (340; 500) or image encoder using intra block copy, BC, prediction, wherein, for intra BC prediction, the sample values of a current block (730; 2210) of a picture are predicted using previously reconstructed sample values in the same picture and a block vector, BV, indicates a displacement from the current block to a block of the picture that includes the previously reconstructed sample values used for prediction, a method comprising: splitting the current block (1900; 2210) into smaller blocks (2221 - 2224) for purposes of intra BC prediction operations; performing block vector, BV, estimation to determine a BV value for the current block, wherein BV estimation comprises, when the encoder evaluates a candidate BV value for the current block that is split into smaller blocks, estimating reconstructed sample values within an overlap area of a current block of a picture, the overlap area covering parts of the current block that are in potential intra-frame prediction reference regions when applying the candidate BV value across all the multiple smaller blocks in zig-zag order; and wherein performing BV estimation comprises using at least some of the estimated reconstructed sample values within the overlap area of the current block, wherein the estimating the reconstructed sample values within the overlap area includes either using the corresponding original sample values as the reconstructed sample values, respectively, within the overlap area; or processing the corresponding original sample values within the overlap area using a frequency transform, quantization, inverse quantization and an inverse frequency transform, and using the processed sample values as the reconstructed sample values, respectively, within the overlap area; and wherein the method comprises performing intra BC prediction for the current block including performing block copy operations on a block-by-block basis at the level of the smaller blocks using the determined BV value. splitting the current block (1900; 2210) into smaller blocks (2221 - 2224) for purposes of intra BC prediction operations; performing block vector, BV, estimation to determine a BV value for the current block, wherein BV estimation comprises, when the encoder evaluates a candidate BV value for the current block that is split into smaller blocks, estimating reconstructed sample values within an overlap area of a current block of a picture, the overlap area covering parts of the current block that are in potential intra-frame prediction reference regions when applying the candidate BV value across all the multiple smaller blocks in zig-zag order; and wherein performing BV estimation comprises using at least some of the estimated reconstructed sample values within the overlap area of the current block, wherein the estimating the reconstructed sample values within the overlap area includes either using the corresponding original sample values as the reconstructed sample values, respectively, within the overlap area; or processing the corresponding original sample values within the overlap area using a frequency transform, quantization, inverse quantization and an inverse frequency transform, and using the processed sample values as the reconstructed sample values, respectively, within the overlap area; and using the corresponding original sample values as the reconstructed sample values, respectively, within the overlap area; or processing the corresponding original sample values within the overlap area using a frequency transform, quantization, inverse quantization and an inverse frequency transform, and using the processed sample values as the reconstructed sample values, respectively, within the overlap area; and wherein the method comprises performing intra BC prediction for the current block including performing block copy operations on a block-by-block basis at the level of the smaller blocks using the determined BV value.