Abstract: Encrypted contents data and a non-core decryption software program are read out from a recording medium. The non-core decryption software program corresponds to a non-core portion of a decryption algorithm. The read-out encrypted contents data is processed into first processed contents data by executing the read-out non-core decryption software program. A hardware decryptor is enabled to process the first processed contents data into second processed contents data by implementing a core portion of the decryption algorithm.

Abstract: A recording apparatus includes a compressive encoder for compressively encoding an input video signal into compression-resultant data whose amount is variable from frame to frame. A first device operates for measuring an accumulative amount of the compression-resultant data generated by the compressive encoder. A second device operates for generating information of a jump destination position when the accumulative amount measured by the first device reaches a predetermined amount. A third device operates for recording the compression-resultant data generated by the compressive encoder and the jump-destination-position information generated by the second device on a recording medium.

Abstract: A disk stores data groups (GOP) of compressed picture data arranged over sectors. A 1st data indicative of a compression method and a 2nd data indicative of the presence of the GOP are contained in a leading sector. Data D (independent frame) is located at the head of the GOP. The 1st and 2nd data and GOP are aligned in order. The 1st data related to a 2nd GOP is detected after data D of the 1st GOP is reproduced to reproduce data D of the 2nd GOP. Data D arranged by an interval in the GOP are reproduced. In a quick traverse/reverse mode, a 2nd data D next to a 1st data D already reproduced is detected from a position of the GOP corresponding to a value obtained by subtracting/adding a fixed value from/to an integerfold of the interval to reproduce the 2nd data. Data D scattered over sectors of a disk are reproduced. Each sector has a 1st and a 2nd field. The 1st field stores signals not interleaved relative to signals of the 2nd field. A positional data of a leading sector is recorded in the 1st field.

Abstract: A disk stores data groups (GOP) of compressed picture data arranged over sectors. A 1st data indicative of a compression method and a 2nd data indicative of the presence of the GOP are contained in a leading sector. Data D (independent frame) is located at the head of the GOP. The 1st and 2nd data and GOP are aligned in order. The 1st data related to a 2nd GOP is detected after data D of the 1st GOP is reproduced to reproduce data D of the 2nd GOP. Data D arranged by an interval in the GOP are reproduced. In a quick traverse/reverse mode, a 2nd data D next to a 1st data D already reproduced is detected from a position of the GOP corresponding to a value obtained by subtracting/adding a fixed value from/to an integerfold of the interval to reproduce the 2nd data. Data D scattered over sectors of a disk are reproduced. Each sector has a 1st and a 2nd field. The 1st field stores signals not interleaved relative to signals of the 2nd field. A positional data of a leading sector is recorded in the 1st field.

Abstract: A variable transfer rate data reproduction system is provided which performs a reproduction operation and a reproduction inhibit operation cyclically to reproduce data recorded on a recording disc. A pickup traces a spiral track formed on the recording disc during the reproduction operation and is also controlled to continue to trace a following portion of the track over a plurality of track turns during the reproduction inhibit operation without a track jump. Upon resumption of the reproduction operation, the pickup jumps over the plurality of tracks to return back to a portion of the track where the reproduction operation has been Interrupted previously. This results in decreased mechanical stress acting on mechanical parts for moving the pickup.

Abstract: A variable transfer rate data reproduction system is provided which performs a reproduction operation and a reproduction inhibit operation cyclically to reproduce data recorded on a recording disc. A pickup traces a spiral track formed on the recording disc during the reproduction operation and is also controlled to continue to trace a following portion of the track over a plurality of track turns during the reproduction inhibit operation without a track jump. Upon resumption of the reproduction operation, the pickup jumps over the plurality of tracks to return back to a portion of the track where the reproduction operation has been interrupted previously. This results in decreased mechanical stress acting on mechanical parts for moving the pickup.

Abstract: A disk stores data groups (GOP) of compressed picture data arranged over sectors. A 1st data indicative of a compression method and a 2nd data indicative of the presence of the GOP are contained in a leading sector. Data D (independent frame) is located at the head of the GOP. The 1st and 2nd data and GOP are aligned in order. The 1st data related to a 2nd GOP is detected after data D of the 1st GOP is reproduced to reproduce data D of the 2nd GOP. Data D arranged by an interval in the GOP are reproduced. In a quick traverse/reverse mode, a 2nd data D next to a 1st data D already reproduced is detected from a position of the GOP corresponding to a value obtained by subtracting/adding a fixed value from/to an integerfold of the interval to reproduce the 2nd data. Data D scattered over sectors of a disk are reproduced. Each sector has a 1st and a 2nd field. The 1st field stores signals not interleaved relative to signals of the 2nd field. A positional data of a leading sector is recorded in the 1st field.

Abstract: A defect detecting apparatus for a disc comprises a first dropout selecting circuit for producing a first dropout detection signal having a predetermined pulse width in accordance with the human eyesight, a second dropout selecting circuit for producing a second dropout detection signal which is obtained by detecting a dropout in a vicinity of a beginning of a reproduced vertical synchronizing signal, an angle detecting circuit for generating an angle detection signal indicative of angular positions on the disc where the first and second dropout detection signals are generated with respect to a reference position which is related to the reference signal, a clog detecting circuit for generating a clog detection signal, a compensating circuit for compensating a value of an address signal which is separated from a signal which is reproduced from the disc in a reproducing apparatus, a processing circuit for performing a first process of discriminating the existence of a tracking error, a second process of discrim