tMsb + pic_order_cnt_lsb (8-4) When the current picture is not a top field, BottomFieldOrderCnt is derived as specified by the following pseudo-code: if( !field_pic_flag) BottomFieldOrderCnt = TopFieldOrderCnt+delta_pic_order_cnt_botton (8-5) BottomFieldOrderCnt = PicOrderCntMsb +pic_order_cnt_lsb 8.2.1.2 Decoding process for picture order count type 1 This process is invoked when pic_order_cnt_type is equal to 1. Input to this process is FrameNumOffset of the previous picture in decoding order as specified in this subclause. Outputs of this process are either or both TopFieldOrderCnt or BottomFieldOrderCnt. The values of TopFieldOrderCnt and BottomFieldOrderCnt are derived as specified in this clause. Let prevFrameNum be equal to the frame_num of the previous picture in decoding order. When the current picture is not an IDR picture, the variable prevFrameNumOffset is derived as follows: If the previous picture in decoding order included a memory_management_control_operation equal to 5, prevFrameNumOffset is set equal to 0. Otherwise (the previous picture in decoding order did not include a memory_management_control_operation equal to 5), prevFrameNumOffset is set equal to the value of FrameNumOffset of the previous picture in decoding order. NOTE - When gaps_in_frame_num_value_allowed_flag is equal to 1, the previous picture in decoding order may be a "non-existing" frame inferred by the decoding process for gaps in frame_num specified in clause 8.2.5.2. The variable FrameNumOffset is derived as specified by the following pseudo-code: if( IdrPicFlag ==1) FrameNumOffset= 0 else if( prevFrameNum > frame_num) (8-6) FrameNumOffset=prevFrameNumOffset +MaxFrameNum = FrameNumOffset = prevFrameNumOffset The variable absFrameNum is derived as specified by the following pseudo-code: if( num_ref_frames_in_pic_order_cnt_cycle 0) absFrameNum = FrameNumOffset + frame_num (8-7) absFrameNum =0 nal ref idc == 0 && absFrameNum > 0) absFrameNum = absFrameNum - 1 Rec. ITU-T H.264 (01/2012) When absFrameNum > 0, picOrderCntCycleCnt 