Methods of image processing with reduced memory requirements for video encoder and decoder

A method of performing image processing, the method comprising:

• storing a reference picture into a frame buffer starting at a first starting address;
• overwriting at least a subset of the reference picture by storing at least a portion of a current picture into the frame buffer starting at a second starting address;
• protecting a plurality of blocks of the reference picture from being lost while storing each block of the current picture in the frame buffer;
• performing a motion compensation procedure for a particular block of the current picture at least in a portion of blocks of the reference picture that are being protected;
• storing the particular block of the current picture in the frame buffer;
• and
• after overwriting at least a block of the current picture into the frame buffer, changing the plurality of blocks of the reference picture that are being protected to stop protecting at least an expired block of the plurality of blocks of the reference picture that are being protected and to start protecting at least a next block of the reference picture.