▁Sec ure B urn , ▁An aho , ▁Fort ium , ▁and ▁others . ▁All ▁of ▁these ▁methods ▁have ▁been ▁circum vent ed ▁( as ▁might ▁have ▁been ▁expected , ▁since ▁all ▁standard ▁DVD ▁players ▁naturally ▁circum vent ▁them ▁to ▁play ▁and ▁navigate ▁the ▁disc s ▁normally ). ▁R ip lock ▁is ▁a ▁feature ▁that ▁reduces ▁drive ▁noise ▁during ▁play back ▁but ▁in ad vert ently ▁reduces ▁ri pping ▁speed . ▁ ▁Dis abled ▁user ▁operations ▁▁ ▁DVD - Video ▁allows ▁the ▁disc ▁to ▁specify ▁whether ▁or ▁not ▁the ▁user ▁may ▁perform ▁any ▁operation , ▁such ▁as ▁selecting ▁a ▁menu , ▁ski pping ▁chap ters , ▁forward ing ▁or ▁re w inding ▁essentially ▁any ▁function ▁on ▁the ▁remote ▁control . ▁This ▁is ▁known ▁as ▁User ▁Operation ▁Pro hib itions , ▁or ▁Pro hib ited ▁User ▁Oper ations ▁( U OP s ▁or ▁P U Os ). ▁Most ▁DVD ▁players ▁respect ▁these ▁commands ▁( e . ▁g ., ▁by ▁prevent ing ▁ski pping ▁or ▁fast - forward ing ▁through ▁a ▁copy right ▁message ▁or ▁an ▁advert is ement ▁at ▁the ▁beginning ▁of ▁a ▁disc ). ▁However , ▁grey ▁market ▁players ▁ignore ▁U OP s ▁and ▁some ▁DVD ▁" re - author ing " ▁software ▁packages ▁allow ▁the ▁user ▁to ▁produce ▁a ▁copy ▁without ▁these ▁restrictions . ▁The ▁leg ality ▁of ▁these ▁activities ▁var ies ▁by ▁juris diction ▁and ▁is ▁the ▁subject ▁of ▁debate . ▁( See ▁fair ▁use .) ▁ ▁Region ▁codes ▁▁ ▁Each ▁DVD - Video ▁disc ▁contains ▁one ▁or ▁more ▁region ▁codes