Macrovision Corporation

Macrovision Europe Limited

Other

Rovi Europe Limited

Richard A A Heylen

Mark Dominic Jackson

Philippe Marcel Henri Selve

Victor Kovner

Jonny Boyd Reckless

Peter Alfred Newman

Roger Edward

The present invention relates to a method of copy protecting optical discs, such as CDs or DVDs. Instead of encoding data onto the CD-ROMs in a conventional manner which ensures balanced dc content, for copy protection the digital data is encoded and recorded onto the optical disc such that it is arranged to give some of the recorded digital data highly unbalanced dc content. Thus, for example, the DSV (digital sum value) value of the encoded data is recorded so that the DSV value changes continuously once 50 frames of data or more.

Method and product for copy protection of optical discs using unbalanced DC content

DVDs can be copy protected by incorporating regions which contain unreadable or subversive data within the data area (). For example, such a region may be configured as a cell of a video object (VOB) () within a VOB file (). Access to the region of subversive data is prevented during normal playback, for example, by ensuring that there are no pointers leading to the subversive region. To defeat such a copy protection method, the content on the copy protected optical disc is accessed by utilising the navigation provided for normal playback of the disc. Thus, the subversive regions are navigated around during copying of the disc. The accessed content is stored in a corresponding data area and, where subversive regions are identified, arbitrary data is incorporated within regions of the copy data area which correspond to regions of unreadable or subversive data in the original data area.

Defeat of the copy protection of optical discs

A copy protection technique is described which enables the content () of an application file (), for example, provided by a licensed game provider, to be copy protected without action having to be taken at the time of encoding the application file onto a DVD or other optical disc. DSV data patterns, that is data patterns which are difficult to encode without causing DSV problems, are to be incorporated in the application file (). It is expected that sophisticated encoders () at games console manufacturers will be able, for example, by using look-ahead techniques, to encode and apply the application to the glass master () in a manner such that the encoded data will not cause DSV problems. However, if an attempt is made to read the data on the original disc, for example, for copying purposes, the DSV data patterns will cause a CD or DVD writer to encode the data onto the copy disc in a manner which renders the resultant copy disc effectively unplayable. The DSV data patterns may be incorporated in an application file () within information, or in control data therof (FIG.).

Method and apparatus for copy protection for applications

The present invention relates to a method of copy protecting optical discs, such as CD-ROMs. Instead of encoding data onto the CD-ROMs in a manner which ensures balanced dc content, for copy protection the digital data is encoded and recorded onto the optical disc such that it is arranged to give some of the recorded digital data unbalanced dc content. Thus, for example, the DSV value of the encoded data may be changed rapidly in less than (100) frames to (FIG.). For an area of digital data on the optical disc in which the DSV has been caused to rise steeply (FIG.), heavy distortions in audio arise (FIG.) during an attempt to copy an audio track including the single segment of unbalanced dc content.

Method and apparatus for the copy protection of optical discs

A method of copy protecting optical discs uses the differences in capability between the encoder associated with a laser beam recorder and that in currently available CD writers. Digital sum value (DSV) is a property of the encoded data on CDs and an encoder, which controls a laser beam recorder may be able to choose a pattern of merge bits which result in the overall DSV having optimal properties. During mastering of a CD, data patterns are added to the disc to provide an authenticating signature. These data patterns are chosen to cause DSV problems. Currently available CD writers have been found to have difficulty writing an authenticating signature of the type described without producing a resulting CD which has severe readability problems. Thus, the copy disc written by the CD writer will result in a CD reader returning corrupted data or information signalling a read error.

Copy protection for optical discs

The method and apparatus described utilise the fact that CDs manufactured from the same master will have distinctive physical characteristics attributable to the physical manufacturing process of the master to distinguish counterfeit CDs from genuine discs. For a genuine disc, the relative angular orientation of specified sections of the recorded data are determined and recorded. The relative angular orientation of the same sections of data on a test disc are also determined. Where the relative angular orientations are the same it is concluded that the test disc derives from the same source as the genuine disc and is therefore bona fide. Where there is no correlation, the test disc may be identified as counterfeit. The relative angular orientations, or other physical characteristics of the discs, may be physically measured, or may be calculated from information gained by reading the data on the disc. The disclosed technique can also be used to copy protect discs.

Method of accessing data on a copy protected data carrying disc

It is proposed to copy protect data files for transmission by incorporating DSV data patterns, that is, data patterns which are difficult to encode without causing DSV problems, in the data files. The data in five audio streams and two video streams is placed, by way of encoders () and a multiplexer () into a stream of blocks of encoded data in the MPEG file format (). In this format, blocks of video data V are arranged alternately with blocks of audio data A and padding stream blocks P. DSV data patterns () are incorporated into the MPEG file () by way of an encoder () to produce the copy protected data file (). The DSV data patterns () are incorporated into locations within the MPEG file which have no data content such as padding stream blocks P and/or into unused audio data blocks A. The DSV data patterns incorporated within the data blocks fed either to a monitor or to a reproduction system will not interfere with the reproduction such that unfettered access is provided to the transmitted information. However, a CD or DVD writer will generally be caused to write a disc which, when read, will result in a reader returning corrupted data or information signalling a read error. Thus, the data in the MPEG filehas been copy protected.

Method and apparatus for data files used in the transmission of information

Method and apparatus for protection of data carrying discs

The ability of a data reader, such as a CD-ROM drive, to access, extract, or otherwise read the data on a digital audio compact disc provides a problem for the music industry. A user can use his CD-ROM drive to read the data from an audio disc into a computer file, and then that data can be copied. To provide copy protection, errors are deliberately introduced into the data on a CD, but these errors are of a type which are generally transparent to an audio player but which will interfere with the reading of the audio data by a data reader. According to the standards, the data on a CD is encoded into frames by EFM (eight to fourteen modulation). Each frame has sync data, sub-code bits providing control and display symbols, data bits and parity bits, and includes 24 bytes of data, which is audio data for a CD-DA. The standard requires that 98 such frames are grouped into a sector. To provide copy protection, each is provided with a non-standard number of frames, for example, has 99 rather than 98 frames. Then the Sand Ssub-code synchronisation patterns are placed one frame later than they otherwise would be, but the data within each frame remains the same. An audio player would divide the 24 bytes of data from each frame of the sector into 4 byte samples and continue playing the disc, albeit with an inaccurate time display. However, a data reader used to read audio data from the CD-DA to enable a copy to be made, would produce a copy having a degraded quality of sound.

Copy protection of digital audio compact discs

The method and apparatus of the invention utilize the fact that CDs manufactured from the same master will have distinctive physical characteristics attributable to the physical manufacturing process of the master to distinguish counterfeit CDs from genuine discs. For a genuine disc ( ), the relative angular orientation of specified sections ( ) of the recorded data are determined and recorded. The relative angular orientation of the same sections ( ) of data on a test disc ( ) are also determined. Where the relative angular orientations are the same it is concluded that the test disc derives from the same source as the genuine disc and is therefore bona fide. Where there is no correlation, the test disc may be identified as counterfeit. The relative angular orientations, or other physical characteristics of the discs, may be physically measured, or may be calculated from information gained by reading the data on the disc.

Method and apparatus for determining the provenance of a data carrying disc

The manufacturing process for a data carrying disc, such as a CD, begins with the production of a master, and in the physical manufacturing process of the master, variations are introduced which give the master distinctive physical characteristics and cause errors in the data. The master is used to form generations of discs, and the physical characteristics of the master are passed on down the generations. A group of discs manufactured from the same source consistently exhibit the physical characteristics of the master, and those physical characteristics are used as a &ldquo;fingerprint&rdquo; for identifying that source. To determine the provenance of a data carrying disc, uncorrected data is read from the disc. Information about errors is extracted from the data read. The error information is then compared with characteristic error information which characterises data carrying discs produced from a well known source to determine whether the data carrying disc has been produced from the known source. The error information extracted is representative of errors arising from the physical manufacturing process.

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Leeds, United Kingdom

Richard A A Heylen