Method of decoding a macroblock based on a macroblock level of the macroblock

A method of determining a reference picture for processing a current field macroblock of an image, comprising:

• determining, by a moving picture decoder, a reference frame picture index in a reference picture list composed of reference frames for the current field macroblock based on a display order;
• determining, by the moving picture decoder, a reference field picture from the reference picture list using index information for a reference field and index information for a reference frame,
• wherein the determined reference field picture has a same parity as the current field macroblock or a different parity from the current field macroblock based on whether the index information for the reference field is an even number or an odd number, the determined reference field picture being one of a top field and a bottom field of a reference frame;
• decoding, by the moving picture decoder, the current field macroblock using the determined reference field picture.