1. A recording medium storing a data structure, the data structure comprising: at least one text subtitle stream, each text subtitle stream including a style segment defining at least one region style and a plurality of presentation segments, each presentation segment containing at least one region of text and the region of text defined by one of the at least one region style, wherein the style segment includes palette information, and each presentation segment further contains a palette update flag which indicates whether to use the palette information defined in the style segment or to use new palette information defined in an associated presentation segment.