gdv Posted November 27, 2010 Posted November 27, 2010 I used the current ImgBurn v2.5.2.0 to create an image of an audio CD on my HDD, then successfully burned and verified a copy of the CD from the image (and the copy seems to play just fine). I didn't realize ImgBurn had the ability to calculate and compare MD5 hashes, so I used CDCheck to generate SHA1 hashes of all the tracks. I thought hashes of the tracks on the burned copy would match the hashes of tracks on the original CD, but none of them matched. Am I confused or misinformed about the nature of audio CD images and CD copies burned from those images? I no longer have the CD copy to do any further testing, but I still have the original CD and the image on my HDD, and I just now re-verified the orignial CD against the image on my HDD with ImgBurn, and got matching MD5 hashes, so I'm even more puzzled. I can set ImgBurn to calculate and compare MD5 hashes, burn another CD copy, and submit the logs if necessary (including the logs for the actions described above), but I thought I should make sure I even understand what to expect before I confuse myself further. Should hashes for the copied CD tracks match hashes for the original CD tracks? Thanks!
LIGHTNING UK! Posted November 27, 2010 Posted November 27, 2010 Unless you have a LiteOn drive or apply the correct offsets when reading/writing, no. Drives don't burn audio data exactly where you tell them to. I've no idea why, they just don't. Everything gets offset by a few bytes either way (depends on the drive), so checksums won't match unless you apply those same offsets when you read/write the data.
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