Apparatus and method for playback of digital content

A digital content playback method which generates new digital content by replacing one or more content parts included in digital content by one or more other content parts, the method comprising:

• providing content storage configured to store a plurality of content parts, and
• license information storage configured to store license information describing license conditions defined for the content parts, each of which includes at least a replacement permission condition and a replacement target specification condition among conditions in which
• the replacement permission condition defines that a content part which has replacement permission is replaceable by another content part,
• the replacement target specification condition specifies content parts which are replacement target candidates when the replacement permission condition is replaceable and
• a complementary relationship condition specifies another content part that must be contained in digital content when using the content part which has replacement permission, and
• an automatic replacement permission condition specifies whether to allow replacement of the content part which has automatic replacement permission without user instruction,
• receiving, from a user, specification of a replacement source content part as a content part that should be replaced among content parts in the digital content including content parts in the content storage, and a replacement target content part as a content part for adding to the digital content for replacing the replacement source content part,
• verifying whether license conditions of content parts in the digital content and the replacement target content part would be satisfied when replacing the replacement source content part by the replacement target content part, and automatically replacing the content part to satisfy complementary relationship conditions of all content parts,
• generating new digital content by replacing the replacement source content part by the replacement target content part when the license conditions are determined as being satisfied as a result of the verifying;
• and
• playing back the generated new digital content, wherein
• license conditions of the content parts in the content storage include an automatic replacement permission condition specifying whether to allow replacement of the content part without receiving user instruction, and
• the specifying includes presenting content parts whose replacement permission condition is replaceable and whose automatic replacement permission condition is impermissible as candidates for the replacement source content part among content parts in the digital content and content parts specified by replacement target specification conditions of the candidates for the replacement source content part as candidates for the replacement target content part, to the user.

A digital content playback apparatus which plays back first digital content by playing back content parts recorded in an optical disk based on a playback control sequence for controlling playback of the content parts and a first license file including a plurality of license information pieces describing license conditions defined for the content parts, the digital content playback apparatus comprising:

• a reading unit configured to read the playback control sequence, the first license file, identification information of the first digital content, information on a place to obtain a playback control sequence to be edited, and the content parts from the optical disk;
• an editing unit configured to
• access the place shown in the information,
• obtain the playback control sequence to be edited and a second license file including one or more license information pieces describing the license conditions for one or more content parts among the content parts, based on identification information of the playback control sequence and the identification information of the first digital content,
• select content parts which have license information pieces describing a permission of enlisting a link and a condition to permit the link, among the content parts, and
• enlist the link to the selected content parts from the playback control sequence to be edited such that the conditions to permit the link described in the license information pieces of the selected content parts are satisfied;
• storage configured to store the playback control sequence edited by the editing unit and the second license file;
• and
• a playback unit configured to play back second digital content by playing back content parts based on the playback control sequence edited by the editing unit and the second license file,
• wherein the playback apparatus utilizes further license information describing further license conditions defined for the content parts, each of which includes at least a replacement permission condition and a replacement target specification condition among conditions in which
• the replacement permission condition defines that a content part which has replacement permission is replaceable by another content part,
• the replacement target specification condition specifies content parts which are replacement target candidates when the replacement permission condition is replaceable,
• a complementary relationship condition specifies another content part that must be contained in digital content when using the content part which has replacement permission, and
• an automatic replacement permission condition which specifies whether to allow replacement of the content part which has automatic replacement permission without user instruction, and
• the playback apparatus presents to the user content parts whose replacement permission condition is replaceable and whose automatic replacement permission condition is impermissible as candidates for a replacement source content part among content parts in the digital content and content parts specified by replacement target specification conditions of the candidates for the replacement source content part as candidates for a replacement target content part.