5. A method of decoding a text subtitle stream, the method comprising: parsing the text subtitle stream downloaded from an external source into first segment and second segments, the first segment including region style information including at least one region style to be applied to a subtitle region including text data, the second segment including the text data to be displayed in the subtitle region and inline style information including at least one font related style to be applied to the text data, the parsed text data and inline style information being transferred to a different area of a text subtitle decoder than the parsed region style information; and converting the text data into bitmap data by rendering the text data with the region style information and the inline style information, wherein a text subtitle stream file including the text subtitle stream is separate from a first clip information file including attribute information corresponding to the text subtitle stream file, wherein an AV stream file including an AV stream is separate from a second clip information file including attribute information corresponding to the AV stream file, the text subtitle stream file and the AV stream file have one-to-one correspondence with the first and the second clip information files, respectively, wherein reproduction of the AV stream is managed by a playitem, and reproduction of the text subtitle stream is managed by a subplayitem, wherein the playitem indicates beginning and ending times for reproduction of the AV stream, and the subplayitem indicates beginning and ending times for reproduction of the text subtitle stream, wherein the AV stream file and the text subtitle stream file are separate files.
7. The method of claim 5 , wherein the inline style information specifies the specific font-related style by redefining at least one of a font identification (font id), a font style (font style), a font size (font size), and a font color (font color).