| 摘要 |
A broadcaster prepares primary content session stream data, and auxiliary content files, such as subtitle text. The auxiliary data may be provided using a two-level structure. Here, the first level can be is a file having plural entries each with a control information item, e.g. a timestamp, and a reference is found. A receiver at a time relating to a timestamp tenders video content from a packet 43 having that timestamp, and also renders subtitle text from the second level file 46 having the same reference as the reference corresponding to the timestamp in the first level file. Thus, the broadcaster defines when subtitle text strings are to be rendered but without requiring streaming of packets including the auxiliary data. This makes it easy for a receiver to synchronise the auxiliary data with the primary content. A single level file structure can be used instead. |
