DTV data stream, DTV broadcast system, and methods of generating and processing DTV data stream

摘要

A digital television (DTV) data stream contains a plurality of subtitle streams having different subtitle sizes and a program map table (PMT) associated with the subtitle streams. The PMT includes a subtitle scale information descriptor which includes a plurality of subtitle scale information sets specifying the subtitle sizes of the subtitle streams, respectively. The subtitle scale information descriptor is included in a second descriptor loop of the PMT, and each subtitle scale information descriptor includes a language code identifying a language of a corresponding subtitle stream, and scale information representing a ratio of a subtitle size of the subtitle stream to a reference subtitle size.