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.

The invention, as shown by the system in FIG. 2, relates to a client-side content tracking system of media files, e.g. digital music files. Audio tracking—or indeed multimedia tracking—is shifted to a client-side perspective, with the client tasked with establishing use of a selected source audio track by tracking—and then reporting uplink to the server—at least one of: entry and exit points associated with playing of at least one of said musical sections in the identified source audio track, and how the identified source audio track was used, performed or manipulated at the client device. Server functionality is designed, having regard to the reported tracking data and its link to a unique identifier to permit the media file (e.g. source audio track) to be selected and/or identified, to store or relay—possibly in the context of a subscription service and billing regime for content use—tracking data related to use of at least a portion of the source audio track at or by the client device. In the context of audio, reporting of use at a client device can, in turn, cause streaming of related multi-media content from a third-party database to the client device. For music, reporting of entry and end points into and out of sections of complete audio tracks can coincide with musically seamless audio transitions between sections.

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.

The invention, as shown by the system in FIG. 2, relates to a client-side content tracking system of media files, e.g. digital music files. Audio trackingor indeed multimedia trackingis shifted to a client-side perspective, with the client tasked with establishing use of a selected source audio track by trackingand then reporting uplink to the serverat least one of: entry and exit points associated with playing of at least one of said musical sections in the identified source audio track, and how the identified source audio track was used, performed or manipulated at the client device. Server functionality is designed, having regard to the reported tracking data and its link to a unique identifier to permit the media file (e.g. source audio track) to be selected and/or identified, to store or relaypossibly in the context of a subscription service and billing regime for content usetracking data related to use of at least a portion of the source audio track at or by the client device. In the context of audio, reporting of use at a client device can, in turn, cause streaming of related multi-media content from a third-party database to the client device. For music, reporting of entry and end points into and out of sections of complete audio tracks can coincide with musically seamless audio transitions between sections.

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 system and method is disclosed for allowing content providers to protect against widespread copying of their content, while enabling them to give their customers more freedom in the way they use the content. In accordance with one embodiment, content providers identify their content as protected by watermarking the content. Consumers use compliant devices to access protected content. All of a user's compliant devices, or all of a family's devices, can be organized into an authorized domain. This authorized domain is used by content providers to create a logical boundary in which they can allow users increased freedom to use their content.