6. The optical disc of claim 3 , wherein the region position specifies at least one of a horizontal position and a vertical position of the text subtitle region within the display screen, the region size specifying at least one of width and height of the text subtitle region, and the text flow specifying at least one of a character progression and a line progression of the text data within the text subtitle region.
3. The optical disc of claim 1 , wherein the default style of the text subtitle region is specified by at least one of a region position, a region size, a region background color, a text position, a text flow, a text alignment, a line space, a font identification, a font style, a font size, and a font color defined in the region style information.