Patent ID: 7734148

Claim:
A method for reproducing sub-picture data in an optical disc device comprising: displaying sub-picture units on a screen; storing, on the optical disc device, a recording start position of each of the sub-picture units at a point in time when the sub-picture unit is displayed on the screen; receiving a predetermined user key input while displaying the sub-picture unit on the screen; searching for the recording start position of a sub-picture unit corresponding to search information generated in accordance with the received predetermined user key input, wherein the searched recording start position corresponds to a recording start position of the sub-picture unit being currently displayed when the user key input is received; and reproducing sub-picture data starting from the searched recording start position, wherein the storing comprises: storing a recording size of each of the sub-picture units displayed on the screen, storing search information associated with the each of the sub-picture units, comparing a recording size of successively inputted sub-picture units with the stored recording size of the sub-picture units, determining that successively inputted sub-picture units are new sub-picture units having new data when the comparing determines that the recording size of one of the successively inputted sub-picture units is different than the stored recording size of the sub-picture units, and storing the recording size of the successively inputted sub-picture units along with search information associated with the successively inputted sub-picture units when the successively inputted sub-picture units are determined to be new sub-picture units having new data, wherein the storing the recording size of the successively inputted sub-picture units is carried out to determine that new sub-picture data is displayed when the recording size of a current sub-picture unit does not correspond to the recording size of a sub-picture unit immediately preceding the current sub-picture unit.