ed by the decoding process for a bitstream conforming to this Recommendation International Standard. A redundant coded picture is not required to contain all macroblocks in the primary coded picture. Redundant coded pictures have no normative effect on the decoding process. See also primary coded picture. 3.122 reference field: A reference field may be used for inter prediction when P, SP, and B slices of a coded field or field macroblocks of a coded frame are decoded. See also reference picture. 3.123 reference frame: A reference frame may be used for inter prediction when P, SP, and B slices of a coded frame are decoded. See also reference picture. 3.124 reference index: An index into a reference picture list. 3.125 reference picture: A picture with nal_ref_idc not equal to 0. A reference picture contains samples that may be used for inter prediction in the decoding process of subsequent pictures in decoding order. 3.126 reference picture list: A list of reference pictures that is used for inter prediction of a P, B, or SP slice. For the decoding process of a P or SP slice, there is one reference picture list. For the decoding process of a B slice, there are two reference picture lists. 3.127 reference picture list 0: A reference picture list used for inter prediction of a P, B, or SP slice. All inter prediction used for P and SP slices uses reference picture list 0. Reference picture list 0 is one of two reference picture lists used for inter prediction for a B slice, with the other being reference picture list 1. 3.128 reference picture list 1: A reference picture list used for inter prediction of a B slice. Reference picture list 1 is one of two reference picture lists used for inter prediction for a B slice, with the other being reference picture list 0. 3.129 reference picture marking: Specifies, in the bitstream, how the decoded pictures are marked for inter prediction. 3.130 reserved: The term reserved, when used in the clauses specifying some values of a particular syntax element, are for future use by 