18. A text subtitle decoder for decoding a text subtitle stream recorded on a recording medium, the text subtitle decoder comprising: a text subtitle processor configured to parse the text subtitle stream into composition information, rendering information, and text data for each region; a composition buffer configured to store the composition arid the rendering information parsed from the text subtitle processor; a dialog buffer configured to store the parsed text data, the text data including one or more text strings for each region; a text renderer configured to render the text strings stored in the dialog buffer into a bitmap object for each region according to the rendering information; a bitmap object buffer configured to store the rendered bitmap object; and a presentation controller configured to compose the bitmap object stored in the bitmap object buffer according to the composition information.
18. A text subtitle decoder for decoding a text subtitle stream recorded on a recording medium, the text subtitle decoder comprising: a text subtitle processor configured to parse the text subtitle stream into composition information, rendering information, and text data for each region; a composition buffer configured to store the composition arid the rendering information parsed from the text subtitle processor; a dialog buffer configured to store the parsed text data, the text data including one or more text strings for each region; a text renderer configured to render the text strings stored in the dialog buffer into a bitmap object for each region according to the rendering information; a bitmap object buffer configured to store the rendered bitmap object; and a presentation controller configured to compose the bitmap object stored in the bitmap object buffer according to the composition information. 21. The text subtitle decoder of claim 18 , wherein the text subtitle processor is configured to parse the text subtitle stream into rendering information including at least a portion of region style information specifying one of the region styles defined by the style segment.