| 摘要 |
A transmitter for transmitting a digital broadcasting signal comprises a multiplexer for multiplexing audio data, video data and control data to output a DTV stream, and a transmitter for transmitting the DTV stream. The video data includes user data bits carrying caption service data for providing a closed caption service. The control data includes a caption service descriptor having a caption information field indicating whether a digital television closed caption service is present in the video data or a line 21 closed caption service is present in the video data in accordance with electronic industry association (EIA) 708, and a caption service number field identifying a caption service number present in an associated EIT event. The caption service number in the caption service descriptor is defined only when the digital television closed caption service is present. |
