Copy protected DVD and method for producing and validating same
AssigneeMacrovision Europe Limited
InventorsBaruch Sollish, Moshe Brody
Life of this patent
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Abstract
A copy protected DVD disc and a method for producing and validating the DVD disc is provided. In an embodiment the method for protecting a DVD from being illegally copied includes producing a signature which includes introducing ambiguous symbols into an ECC block and partially disabling the error correction. A DVD encoder for use in producing the copy protected disc is also provided.
Claims31
A method for producing a signature on a DVD disc comprising:
- partially disabling error correction prior to EFM+ encoding;
- and
- introducing at least one ambiguous symbol into an ECC block during EFM+ encoding, said ambiguous symbol having a value which can be read as either a first value or a second alternate value.
A method for validating a signature on a DVD comprising:
- comparing the number of reads for at least one unprocessed sector within the ECC block to be read correctly with the number of reads for at least one processed sector within said ECC block to be read correctly, wherein said ECC block comprises a partially disabled ECC written to the DVD.
A method for validating a signature on a DVD comprising:
- comparing the time to successfully read at least one unprocessed sector within the ECC block with the time to read at least one processed sector within said ECC block, wherein said ECC block comprises a partially disabled ECC written on to the DVD.
A method for producing a signature on a digital optical disc (DVD) comprising:
- altering the value of at least one component in the lead-in zone of the DVD,
- whereby, on reading the DVD structure of an authentic DVD, the altered value of said at least one component will be returned.
A DVD encoder comprising;
- an error correction disabler;
- and
- an ambiguous symbol generator, wherein said generated ambiguous symbol has a value which can be read as either a first value or a second alternate value.
A DVD encoder comprising:
- an invalid Reed-Solomon parity symbol generator.
A DVD disc comprising:
- a signature, said signature having at least one ambiguity resulting from at least one ambiguous symbol inserted into an ECC block, during EFM+ encoding and having partially disabled error correction, said partially disabled error correction being produced prior to EFM+ encoding, wherein said ambiguous symbol has a value which can be read as either a first value or a second alternate value.
A DVD disc comprising:
- means for producing a signature on a DVD disc, said signature comprising:
- means for partially disabling error correction prior to EFM+ encoding;
- and
- means for introducing at least one ambiguous symbol into an ECC block during EFM+ encoding, said ambiguous symbol having a value which can be read as either a first value or a second alternate value.
Dependencies are inferred from the claim text.