Recording medium, reproduction device, recording method, and reproduction method

A playback apparatus for detecting combinations of conditions, among a plurality of conditions, that are satisfied by each of a plurality of text subtitle streams specified by playlist section information included in playlist information recorded on a recording medium, selecting one among the plurality of text subtitle streams in accordance with the combination of satisfied conditions, and playing back the selected text subtitle stream, wherein

• a first condition among the plurality of conditions is that an ability to decode and convert character codes representing a subtitle into a bit map is present in the playback apparatus,
• a second condition is that an ability to process a text subtitle stream corresponding to a display method unique to each language is present in the playback apparatus,
• a third condition is that a language code of a text subtitle stream matches a language setting in the playback apparatus,
• the playlist information includes MainPath information and SubPath information, the MainPath information including two or more pieces of playback section information,
• each piece of playback section information includes (i) a playback start point and a playback end point of the AV stream, and (ii) a stream number table that indicates one or more text subtitle streams that can be played back in synchronization with the AV stream,
• the stream number table includes a plurality of entries, the plurality of entries including one or more entries of text subtitle streams, each entry of the text subtitle stream includes a SubPath identifier reference, a substream identifier reference, and a packet identifier reference,
• the SubPath identifier reference indicating a SubPath corresponding to a text subtitle stream,
• the substream identifier reference defining a substream which includes a text subtitle stream to be pre-loaded into a buffer of a playback apparatus before a playback of an AV stream is started by an AV decoder of the playback apparatus in accordance with a piece of playback section information,
• the packet identifier reference defining packets of a text subtitle stream to be demultiplexed by a demultiplexing unit of the playback apparatus, and
• the SubPath identifier reference, the substream identifier reference, and the packet identifier reference included in each entry of all text subtitle streams have a same description in stream number tables in a piece of playback section information, which is second or after in order in the playlist information, and in a piece of playback section information immediately before thereof, when the AV decoder of the playback apparatus is to be caused to perform a process of seamlessly connecting the second or after piece of playback section information with the piece of playback section information immediately before thereof,
• the playback apparatus comprising:
• a register set storing therein a flag that indicates whether or not the playback apparatus permits itself to select a text subtitle stream corresponding to a display method unique to a language that the playback apparatus does not have an ability to process;
• a pre-load unit operable to, before the AV stream is played back in accordance with the piece of playback section information, read a text subtitle stream from the recording medium and pre-load the read text subtitle stream into a buffer;
• and
• a selecting unit operable to judge whether a text subtitle stream satisfies the first condition, the second condition, and the third condition with respect to each of one or more text subtitle streams specified by the playback section information, and select one among text subtitle streams that are judged to satisfy the first condition, the second condition, and the third condition, wherein
• the selecting unit regards, as a selection target, a text subtitle stream that satisfies the first condition and the third condition if the flag stored in the register set indicates that the playback apparatus permits itself to select a text subtitle stream corresponding to a display method unique to a language that the playback apparatus does not have an ability to process.

A recording method for recording playlist information, an AV stream, and a sub stream onto a recording medium, wherein

• the playlist information includes MainPath information and SubPath information, the MainPath information including two or more pieces of playback section information,
• each piece of playback section information includes (i) a playback start point and a playback end point of the AV stream, and (ii) a stream number table that indicates one or more text subtitle streams that can be played back in synchronization with the AV stream,
• the stream number table includes a plurality of entries, the plurality of entries including one or more entries of text subtitle streams, each entry of the text subtitle stream includes a SubPath identifier reference, a substream identifier reference, and a packet identifier reference,
• the SubPath identifier reference indicating a SubPath corresponding to a text subtitle stream,
• the substream identifier reference defining a substream which includes a text subtitle stream to be pre-loaded into a buffer of a playback apparatus before a playback of an AV stream is started by an AV decoder of the playback apparatus in accordance with a piece of playback section information,
• the packet identifier reference defining packets of a text subtitle stream to be demultiplexed by a demultiplexing unit of the playback apparatus, and
• the SubPath identifier reference, the substream identifier reference, and the packet identifier reference included in each entry of all text subtitle streams have a same description in stream number tables in a piece of playback section information, which is second or after in order in the playlist information, and in a piece of playback section information immediately before thereof, when the AV decoder of the playback apparatus is to be caused to perform a process of seamlessly connecting the second or after piece of playback section information with the piece of playback section information immediately before thereof.

A playback method for causing a computer to execute a process of detecting combinations of conditions, among a plurality of conditions, that are satisfied by each of a plurality of text subtitle streams specified by playlist section information included in playlist information recorded on a recording medium, selecting one among the plurality of text subtitle streams in accordance with the combination of satisfied conditions, and playing back the selected text subtitle stream, wherein

• a first condition among the plurality of conditions is that an ability to decode and convert character codes representing a subtitle into a bit map is present in the computer,
• a second condition is that an ability to process a text subtitle stream corresponding to a display method unique to each language is present in the computer,
• a third condition is that a language code of a text subtitle stream matches a language setting in the computer,
• the playlist information includes MainPath information and SubPath information, the MainPath information including two or more pieces of playback section information,
• each piece of playback section information includes (i) a playback start point and a playback end point of the AV stream, and (ii) a stream number table that indicates one or more text subtitle streams that can be played back in synchronization with the AV stream,
• the stream number table includes a plurality of entries, the plurality of entries including one or more entries of text subtitle streams, each entry of the text subtitle stream includes a SubPath identifier reference, a substream identifier reference, and a packet identifier reference,
• the SubPath identifier reference indicating a SubPath corresponding to a text subtitle stream,
• the substream identifier reference defining a substream which includes a text subtitle stream to be pre-loaded into a buffer of a playback apparatus before a playback of an AV stream is started by an AV decoder of the playback apparatus in accordance with a piece of playback section information,
• the packet identifier reference defining packets of a text subtitle stream to be demultiplexed by a demultiplexing unit of the playback apparatus, and
• the SubPath identifier reference, the substream identifier reference, and the packet identifier reference included in each entry of all text subtitle streams have a same description in stream number tables in a piece of playback section information, which is second or after in order in the playlist information, and in a piece of playback section information immediately before thereof, when the AV decoder of the playback apparatus is to be caused to perform a process of seamlessly connecting the second or after piece of playback section information with the piece of playback section information immediately before thereof,
• the computer comprising:
• a register set storing therein a flag that indicates whether or not the playback apparatus permits itself to select a text subtitle stream corresponding to a display method unique to a language that the playback apparatus does not have an ability to process,
• the playback method comprising:
• judging whether a text subtitle stream satisfies the first condition, the second condition, and the third condition with respect to each of one or more text subtitle streams specified by the playback section information, and selecting one among text subtitle streams that are judged to satisfy the first condition, the second condition, and the third condition, wherein
• said selecting regards, as a selection target, a text subtitle stream, among the plurality of text subtitle streams recorded on the recording medium, that satisfies the first condition and the third condition if the flag stored in the register set indicates that the computer permits itself to select a text subtitle stream corresponding to a display method unique to a language that the playback apparatus does not have an ability to process.