Cyclical redundancy, what is it?

[moviebuff2]

Hi everyone:

I have a dvd movie of which I only want to make copy of the main title. No extras.

I used DVDshrink 3.2.0.15. The software analyzed the title successfully (I previewed the film from the beginning to the end).

However, the software encountered an error when it attempted to encode the vts_02 file. The error message was "cyclical redundancy".

Would someone please tell me what this error means and how I can correct it?

Thanks

[budz]

try using DVDFAB DECRYPTER to rip the movie first. usually cycle redunancy errors can be from the dvd disc being dirty or scratched.

[moviebuff2]

Thanks, I will give it a try.

[guns1inger]

Once upon a time you only saw cyclical redundancy with dirty or scratched discs. ArCoSs, by the way it works, mimics (or tries to) physical damage to the structure. The older rippers interpret it in the same way as they would physical damage. Newer rippers aren't fooled by this.

[redwudz]

Wikipedia has a good definition: http://en.wikipedia.org/wiki/Cyclic_redundancy_check

A CRC can be used in the same way as a checksum to detect accidental alteration of data during transmission or storage.

[oldandinthe way]

A cyclic redundancy check is a mathematical technique in which a complex polynomial is used to calculate an error-detection code to determine whether data has been corrupted. CRCs can be created in in varying bit lengths providing greater or lessor error detection capability. Common types are CRC-16 and CRC-32.

A more human factors oriented programmer would report a data error, which would be obvious in it meaning, rather than cyclic redundancy.

Thanks to the movie studios, data errors are now of two types - failed or scratched media, and manufactured as part of a copy protection scheme.

As commented above, DVDshrink does not know the difference between the two causes of this error. Newer rippers do, some older rippers can be told to ignore data errors after some number of retries and can copy some scratched and damaged disks as well as some protected disks. When the damage is real there may be some minor disruptions in the video.

[moviebuff2]

Thank you for taking your time to explain to me CRC.

DVDFab HD Decrypter worked like a charm.