A non-transitory tangible recording medium stores recorded AV data. The AV data includes a system stream file played by a playback device and a management information file having management information corresponding to the system stream file. The system stream file includes a first segment including repeated a first data unit that be decrypted using a first decryption key that the playback device individually has and a second data unit that cannot be decrypted by the first decryption key. The system stream file also includes a second segment which can be decrypted using a second decryption key that the playback device has in common with another playback device. The management information file has a start source packet number, which identifies a start source packet out of a plurality of source packets storing an I-picture that is a random access point, and the start source packet is situated in the second segment.

A non-transitory tangible recording medium stores recorded AV data. The AV data includes a system stream file played by a playback device and a management information file having management information corresponding to the system stream file. The system stream file includes a first segment including repeated a first data unit that be decrypted using a first decryption key that the playback device individually has and a second data unit that cannot be decrypted by the first decryption key. The system stream file also includes a second segment which can be decrypted using a second decryption key that the playback device has in common with another playback device. The management information file has a start source packet number, which identifies a start source packet out of a plurality of source packets storing an I-picture that is a random access point, and the start source packet is situated in the second segment.

A playback method and a playback device for playing a system stream file are provided. The playback method uses the playback device having one or more memories and circuitry to play the system stream file. The playback method includes reading the system stream file and identifying whether the system stream file to be played back is a first system stream file having a first file format or a second system stream file having a second file format. If the system stream file to be played back is the first system stream file, the method further includes converting a file format of the system stream file that has been read out from the first file format into the second file format. The playback method further includes decoding the system stream file having the second file format.

A non-transitory tangible recording medium storing AV data having a system stream file is provided. The system stream file is played by a playback device. The system stream file includes an individual decryption key and a common decryption key. The individual decryption key is owned individually by each of multiple playback devices. The common decryption key is owned in common by the playback devices. The system stream file includes a first system stream file to be played back using both the individual decryption key and the common decryption key. The system stream file also includes a second system stream file to be played back using only the common decryption key among the individual decryption key and the common decryption key.

A non-transitory tangible recording medium storing AV data having a system stream file is provided. The system stream file is played by a playback device. The system stream file includes an individual decryption key and a common decryption key. The individual decryption key is owned individually by each of multiple playback devices. The common decryption key is owned in common by the playback devices. The system stream file includes a first system stream file to be played back using both the individual decryption key and the common decryption key. The system stream file also includes a second system stream file to be played back using only the common decryption key among the individual decryption key and the common decryption key.

A playback method and a playback device for playing a system stream file are provided. The playback method uses the playback device having one or more memories and circuitry to play the system stream file. The playback method includes reading the system stream file and identifying whether the system stream file to be played back is a first system stream file having a first file format or a second system stream file having a second file format. If the system stream file to be played back is the first system stream file, the method further includes converting a file format of the system stream file that has been read out from the first file format into the second file format. The playback method further includes decoding the system stream file having the second file format.

A playback method using a playback device that plays a system stream file is provided. The playback device includes an individual decryption key that is owned individually by each of playback devices, and a common decryption key that is owned in common by a plurality of playback devices. The system stream file includes a first system stream file configured to be played back using both the individual decryption key and the common decryption key, and a second system stream file configured to be played back using only the common decryption key among the individual decryption key and the common decryption key. The method includes identifying whether the system stream file to be playback is the first system stream file or the second system stream file, in accordance with a file extension of the system stream file, and selecting a decryption process of the system stream file.

A playback method using a playback device that plays a system stream file is provided. The playback device includes an individual decryption key that is owned individually by each of playback devices, and a common decryption key that is owned in common by a plurality of playback devices. The system stream file includes a first system stream file configured to be played back using both the individual decryption key and the common decryption key, and a second system stream file configured to be played back using only the common decryption key among the individual decryption key and the common decryption key. The method includes identifying whether the system stream file to be playback is the first system stream file or the second system stream file, in accordance with a file extension of the system stream file, and selecting a decryption process of the system stream file.

A memory storing AV data for playing back encrypted video on a playback device is provided. The AV data includes a system stream file including encrypted video information, and a management information file. The system stream file includes a first segment in which is repeated a first data unit that can be individually decrypted using a first decryption key, and has a second data unit of the same data size as the first data unit but cannot be decrypted by the first decryption key. The system stream file also includes a second segment which can all be decrypted using a second decryption key that the playback device has in common with another playback device. The management information file has a time map in which are correlated I-picture serving as random access point, and a presentation clock time of the I-picture. The I-picture is multiplexed in the second segment.

A memory storing AV data for playing back encrypted video on a playback device is provided. The AV data includes a system stream file including encrypted video information, and a management information file. The system stream file includes a first segment in which is repeated a first data unit that can be individually decrypted using a first decryption key, and has a second data unit of the same data size as the first data unit but cannot be decrypted by the first decryption key. The system stream file also includes a second segment which can all be decrypted using a second decryption key that the playback device has in common with another playback device. The management information file has a time map in which are correlated I-picture serving as random access point, and a presentation clock time of the I-picture. The I-picture is multiplexed in the second segment.