Patent ID: 7843999

Claim:
A method of determining a reference field picture for decoding a current field macroblock in a bi-predictive frame, comprising: determining, by a moving picture decoder, a reference frame picture index in a reference picture list for the bi-predictive frame based on a display order; determining, by the moving picture decoder, a reference field picture for the current field macroblock from the reference picture list, the determined reference field picture being one of a top field and a bottom field of a reference frame; wherein the determining step determines a field having a same parity as the current field macroblock or a different parity from the current field macroblock as the reference field picture based upon reference picture index information, the reference frame picture index, and field parity of the current field macroblock, wherein if the reference picture index information is an odd index number, then the determined field has a field parity different from the current field macroblock decoding the current field macroblock using the determined reference field picture.