1. A method for decoding a text subtitle stream recorded on a recording medium, the method comprising: loading the text subtitle stream into a subtitle loading buffer, the text subtitle stream including a dialog style segment defining a group of region styles and a dialog presentation segment including dialog presentation information and dialog text data for a dialog having at least one region; parsing the dialog presentation segment into composition information, rendering information, and the dialog text data for each region; storing the parsed composition and rendering information in a first buffer, and further storing the dialog text data in a second buffer, the dialog text data including one or more text strings for each region; rendering the text strings stored in the second buffer into a bitmap object for each region according to the rendering information, and storing the rendered bitmap object into a third buffer; and composing the stored bitmap object in a graphics plane for each region according to the composition information.