Patent ID: 8335424

Claim:
A playback apparatus that performs a Picture in Picture playback in accordance with main playback section information and sub playback section information that constitute play list information, composes subtitle streams with secondary video streams and plays back the composed streams, the Picture in Picture playback using a primary video stream and a secondary video stream, the main playback section information including time information and a stream entry table, the time information indicating a start point and an end point of a playback section of a primary video stream, the sub playback section information including time information that indicates a start point and an end point of a playback section of a secondary video stream, the stream entry table including entries of secondary video streams that are permitted to be played among a plurality of secondary video streams, entries of subtitle streams that are permitted to be played among a plurality of subtitle streams, first number information, second number information, and combination information, the first number information indicating the number of entries of subtitle streams that are permitted to be played among the entries of subtitle streams included in the table, a total of the numbers indicated by the first number information and the second number information indicating the number of entries of subtitle streams that are permitted to be played while the Picture in Picture is executed, the combination information indicating subtitle streams that are allowed to be combined with a secondary video stream, the playback apparatus comprising: a first stream number register that stores therein a stream number of a current secondary video stream, and a second stream number register that stores therein a stream number of a current subtitle stream, wherein when a stream number of a current secondary video stream changes, the playback apparatus judges whether or not a stream number of a current subtitle stream stored in the second stream number register falls in a range of values corresponding to the total of the numbers indicated by the first number information and the second number information and whether or not a plurality of predetermined conditions are satisfied, and if a result of the judgment is in the affirmative, the playback apparatus retains the current subtitle stream, and if the result is in the negative, the playback apparatus selects a new subtitle stream, the plurality of predetermined conditions including a condition that the combination information indicates that a current subtitle stream is allowed to be combined with a current secondary video stream whose stream number is stored in the first stream number register.