What is Circular Redundancy?

[etrurian]

Hi,
I just purchased two new releases and attempted to back them up with DVDShrink first (there was an error and the program couldn't continue.). Then I tried DVDDecrypter which halter about a minute into doing its thing complaining about Circular Redundancy.??? The discs are both brand new out of their respective DVD Cases without a scratch. They play well in the stand-alone but won't copy. Both flicks are from Revolution Studios if that means anything. Can someone suggest an alternative method of processing? Or a solution of any sort? TIA

[jggimi]

I'm guessing that your error message was about Cyclic Redunancy rather than "circular."

Be sure you have the latest release of DVD Decrypter (3.5.2.0 currently), first.

Then, search the Decrypting forum for "cyclic redundancy check," "cyclic," or CRC. You will learn that there is a new technique being used by some DVD production companies that intentionally produces bad sectors on DVD.

From Wikipedia:A cyclic redundancy check (CRC) is a type of hash function used to produce a checksum which is a small integer from a large block of data, such as network traffic or computer files, in order to detect errors in transmission or duplication. CRCs are calculated before and after transmission or duplication, and compared to confirm that they are the same. The most widely used CRC calculations are constructed in ways such that certain types of errors, such as those due to noise in transmission channels, are almost always detected.

[2COOL]

Originally posted by etrurian
I just purchased two new releases and attempted to back them up with DVDShrink first (there was an error and the program couldn't continue.). From the official DVD Shrink FAQ, http://forum.digital-digest.com/showthread.php?s=&threadid=44907