Ngokucacileyo, i-horizontal or vertical flip is applied as a filter, which needs a re-encode because the coded frames themselves change; the audio stream is copied through untouched. Ukhetha umgca ohamba phambili - othe tyaba uvelisa umfanekiso we mirror, othe nkqo uvelisa umbono ojikelezayo - kwaye ifayile yonke iguqulwa kuyo.