Method and system for overriding error correction

• US 6,311,305 B1
• Filed: 03/02/1998
• Issued: 10/30/2001
• Est. Priority Date: 03/06/1997
• Status: Expired due to Term

• Current Assignee: Rovi Europe Limited (Adeia Inc.)
• Original Assignee: TTR Technologies Ltd. (Advance Auto Parts Incorporated)
• Inventors: Howe, Dennis, Sollish, Baruch
• Primary Examiner(s): Decady, Albert
• Assistant Examiner(s): LAMARRE, GUY J
• Application Number:
  US09/032,905
• Time in Patent Office: 1,338 Days
• Field of Search: 714/787, 714/756, 714/784, 714/719, 714/758, 714/776, 714/44, 714/710, 395/180, 380/4, 380/49, 341/69, 341/144, 341/106, 369/53.23, 369/53.22, 369/112.24, 369/44.27, 369/44.29, 369/44.13, 369/116, 369/47.11, 369/47.22, 369/59.21, 369/124.09, 369/275.3, 369/47.15, 369/59.25, 369/59.26, 385/7, 385/16, 385/40, 358/518, 358/520, 358/521, 358/524, 359/136, 345/431, 370/358, 348/641, 348/725, 386/126, 386/45, 375/346, 360/40, 360/15, 360/48, 360/53
• US Class Current: 714/784
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00123 the record carrier being identified by recognising some of its unique characteristics, e.g. a unique defect pattern serving as a physical signature of the record carrier
• CPC Class Codes: G11B 20/00579 said format change concerning the data encoding, e.g., modulation schemes violating run-length constraints, causing excessive DC content, or involving uncommon codewords or sync patterns
• CPC Class Codes: G11B 20/00927 wherein said defects or errors are generated on purpose, e.g. intended scratches
• CPC Class Codes: G11B 20/1426 conversion to or from block codes or representations thereof
• CPC Class Codes: G11B 20/18 Error detection or correction; Testing , e.g. of drop-outs
• CPC Class Codes: H03M 13/00 Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes error detection or error correction for analogue/digital, digital/analogue or code conversion H03M1/00 – H03M11/00; specially adapted for digital computers G06F11/08; for information storage based on relative movement between record carrier and transducer G11B, e.g. G11B20/18; for static stores G11C
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• CPC Class Codes: H03M 13/29 combining two or more codes or code structures, e.g. product codes, generalised product codes, concatenated codes, inner and outer codes
• CPC Class Codes: H03M 13/2909 Product codes
• CPC Class Codes: H03M 13/2924 Cross interleaved Reed-Solomon codes [CIRC]
• CPC Class Codes: H03M 13/293 with erasure setting
• CPC Class Codes: H03M 13/35 Unequal or adaptive error protection, e.g. by providing a different level of protection according to significance of source information or by adapting the coding according to the change of transmission channel characteristics

Abstract

A method and system for overriding error correction capabilities of digital optical media is provided. The overriding of the error correction codes (ECC) is accomplished by causing a non-correctable pattern of erroneous symbols to occur in the ECC codeword. Specific redundancy symbols are replaced with invalid symbols. The non-correctable error pattern is recognized by the ECC decoder as being non-correctable and the ECC decoder does not attempt to change the values of any symbols of an ECC codeword that is contaminated by the detectable non-correctable error pattern.

Claims

1. A method for overriding error correction on a digital optical medium, the method comprising the steps of:

prior to EFM encoding, determining the error-correction code codeword in which a non-correctable predetermined symbol is to be contained and causing a non-correctable pattern of erroneous symbols to occur in the error-correction code codeword; and

following EFM encoding, storing the predetermined symbol and said pattern of erroneous symbols on the digital optical medium.

2. The method according to claim 1, wherein the error-correction code codeword is of a type selected from the group consisting of Reed-Solomon codewords, Cross-Interleave Reed-Solomon Code codewords, and Reed-Solomon Product Code codewords.

3. The method according to claim 1, wherein the digital optical medium is of a type selected from the group consisting of Compact Disc, Compact Disc Read-Only-Memory and Digital Video Disc.

4. The method according to claim 1, wherein the digital optical medium is recorded individually by a computer-controlled optical recorder.

5. The method according to claim 1, wherein said causing a non-correctable pattern of erroneous symbols to occur in the error-correction code codeword code codeword comprises the steps of:

selecting at least one arbitrary symbol from the error-correction code codeword, exclusive of the predetermined symbol; and

replacing each of said at least one arbitrary symbol with erroneous symbols.

6. The method according to claim 5, wherein the error-correction code codeword contains redundancy symbols, and wherein at least one of said at least one arbitrary symbol is a redundancy symbol.

7. The method according to claim 5, wherein said erroneous symbols are selected from the group consisting of run length limited errors, erroneous data, invalid channel bit code sequences, and unused channel bit code sequence.

8. The method according to claim 5, wherein the predetermined symbol is to be contained in a plurality of error-correction codewords, the method further comprising the steps of:

prior to EFM encoding

performing said determining for at least two of the error-correction codewords;

performing said selecting of said arbitrary symbols for at least two of the error-correction codewords; and

performing said replacing for at least two of the error-correction codewords.

9. The method according to claim 1, wherein the digital optical medium is of a type selected from the group consisting of Compact Disc, Compact Disc Read-Only-Memory, and Digital Video Disc.

10. A method for overriding error correction on a digital optical medium, said digital optical medium having a lead-out area with a plurality of sectors, the method comprising the steps of:

prior to EFM encoding, determining an error-correction code codeword in which a non-correctable predetermined symbol is to be contained, and causing a non-correctable pattern of erroneous symbols to occur in the error-correction code codeword; and

following EFM encoding, locating the final sector of the lead-out area; and

storing at least one non-correctable predetermined symbol in said final sector.

11. The method according to claim 10, wherein the digital optical medium is of a type selected from the group consisting of Compact Disc, Compact Disc Read-Only-Memory, and Digital Video Disc.

12. The method according to claim 10, wherein the digital optical medium is recorded individually by a computer-controlled optical recorder.

13. A digital optical medium, configured for overriding error correction, said digital optical medium comprising:

at least one sector having at least one non-correctable predetermined symbol located therein;

wherein, prior to EFM encoding, said at least one non-correctable predetermined symbol is replaced by one of a non-correctable pattern of erroneous symbols created prior to EFM encoding.

14. The digital optical medium according to claim 13, further comprising a lead-out area having at least one sector, wherein said at least one predetermined symbol is located in said at least one sector of said lead-out area.

15. The digital optical medium according to claim 13, furthermore of a type selected from the group consisting of Compact Disc, Compact Disc Read-Only-Memory, and Digital Video Disc.

16. The digital optical medium according to claim 13, furthermore recorded individually by a computer-controlled optical records.

17. The digital optical medium according to claim 13, further comprising at least one error-correction code codeword, said at least one error-correction code codeword containing said at least one predetermined symbol and said non-correctable pattern of erroneous symbols.

18. The digital optical medium according to claim 17, wherein said at least one error-correction code codeword is of a type selected from the group consisting of Reed-Solomon codewords, Cross-Interleave Reed-Solomon Code codewords, and Reed-Solomon Product Code codewords.

19. The digital optical medium according to claim 17, wherein said non-correctable pattern of erroneous symbols comprises at least one erroneous symbol.

20. The digital optical medium according to claim 19, wherein said at least one erroneous symbol is selected from the group consisting of run length limited errors, erroneous data, invalid channel bit code sequences, and unused channel bit code sequences.

21. A system for overriding error correction on a digital optical medium, said digital optical medium comprising at least one error-correction code codeword, said at least one error-correction code codeword containing said at least one non-correctable predetermined symbol and a non-correctable pattern of erroneous symbols, said system comprising:

a determinator to determine the error-correction code codeword in which said predetermined symbol is to be contained;

an invalid symbol generator for creating erroneous symbols prior to EFM encoding; and

a replacing unit to replace said predetermined symbol by one of said erroneous symbols prior to EFM encoding and

following EFM encoding, a storage unit to store said predetermined symbol and said erroneous symbols on said digital optical medium.

22. A system according to claim 21 and wherein said determinator comprises an encoder or creating said predetermined symbol.

23. A system according to claim 21 and further comprising:

a multiplexer coupled between said determinator and said laser writing controller;

a laser writing controller coupled to said determinator; and

a timing and control unit coupled to said multiplexer.

24. A system according to claim 23 and wherein said timing and control unit keeps track of the current frame and symbol currently being written to on said digital optical medium.

25. A system according to claim 24 and wherein said timing and control unit further comprises intercept means for intercepting said error-correcting symbols for replacement by said erroneous symbols.

26. A system according to claim 21, wherein said erroneous symbols are selected from the group consisting of run length limited errors, erroneous data, invalid channel bit code sequences, and unused channel bit code sequences.

27. A system according to claim 21, wherein the error-correction code codewords is of a type selected from the group consisting of Reed-Solomon codewords, Cross-Interleave Reed-Solomon Code codewords, and Reed-Solomon Product Code codewords.

28. A system according to claim 21, wherein the digital optical medium is of a type selected from the group consisting of Compact Disc, Compact Disc Read-Only-Memory and Digital Video Disc.