A method includes determining whether a reference block for a current block is located in a different coding tree unit (CTU) than a CTU of the current block. If the reference block is located in the different CTU, the method includes determining whether the CTU of the current block and a memory have a same size. If the CTU of the current block and reference sample memory have a same size, the method includes (i) determining a first area in the CTU of the current block collocated with a second area in the different CTU; (ii) determining, based on a decoding status of the first area, whether a memory location of the memory for the reference block is available; and (iii) if the memory location for the reference block is available, retrieving, from the memory location, one or more samples to decode the current block.