ll not contain data that result in a variable picNumLX that is equal to the PicNum of a picture marked as "non-existing" in any invocation of the modification process for reference picture lists for short-term reference pictures specified in clause 8.2.4.3.1. Rec. ITU-T H.264 (01/2012) d) The bitstream shall not contain data that result in a variable picNumLX that is equal to the PicNum of a picture marked as "non-existing" in any invocation of the assignment process of a LongTermFrameldx to a short-term reference picture specified in clause 8.2.5.4.3. NOTE 3 - The above constraints specify that frames that are marked as "non-existing" by the process specified in this clause must not be referenced in the inter prediction process (clause 8.4, including the derivation process for co-located 4x4 sub-macroblock partitions in clause 8.4.1.2.1), the modification commands for reference picture lists for short-term reference pictures (clause 8.2.4.3.1), or the assignment process of a LongTermFrameldx to a short-term reference picture (clause 8.2.5.4.3). When pic_order_cnt_type is not equal to 0, TopFieldOrderCnt and BottomFieldOrderCnt are derived for each of the "non-existing" frames by invoking the decoding process for picture order count in clause 8.2.1. When invoking the process in clause 8.2.1 for a particular "non-existing" frame, the current picture is considered to be a picture considered having frame inferred to be equal to UnusedShortTermFrameNum, nal ref ide inferred to be not equal to 0, nal_unit_type inferred to be not equal to 5, IdrPicFlag inferred to be equal to 0, field_pic_flag inferred to be equal to 0, adaptive_ref_pic_marking_mode_flag inferred to be equal to 0, delta_pic_order_cnt[ (if needed) inferred to be equal to 0, and delta_pic_order_cnt[1] (if needed) inferred to be equal to 0. NOTE 4 - The decoding process should infer an unintentional picture loss when any of these values of frame_num pertaining to "non-existing" pictures is referred to in the inter prediction process (clause 8.4, including