Exact Audio Copy
How Ripping Works
CDs store digital data, but the interface between CDs, lasers, and optical diodes is very analog. Read errors can be caused by anything from dirty media, to scratches on the protective polycarbonate layer, to vibration from the optical drive itself. The primitive error correction codes in the CDDA standard, designed to minimize audible distortions on lightly used disks, are not capable of fully recovering the bitstream on CDs with a significant error rate. Contemporary CD ripping software works around this with two important error detection techniques: redundant reads and AccurateRip.
Exact Audio Copy (EAC) Exact Audio Copy, more commonly known as just EAC, is a free tool for archiving and format shifting audio CDs. It uses advanced techniques like multi-reading and AccurateRip to ensure you get the most accurate copy of your CD possible. It can also be used to encode music into such popular formats as MP3, FLAC, and AAC. Exact Audio Copy (aka EAC) is a so called audio grabber for audio CDs using standard CD and DVD-ROM drives. It works with a technology, which reads audio CDs almost perfectly. If there are any errors that can’t be corrected, it will tell you on which time position the (possible) distortion occurred, so you could easily control it with e.g. Exact Audio Copy (aka EAC) is a so called audio grabber for audio CDs using standard CD and DVD-ROM drives. It works with a technology, which reads audio CDs almost perfectly. If there are any errors that can’t be corrected, it will tell you on which time position the (possible) distortion occurred, so you could easily control it with e.g.
The page EAC: Extraction Technology describes EAC's approach to redundant reads:
Exact Audio Copy Review
In secure mode this program either reads every audio sector at least twice [...] If an error occurs (read or sync error), the program keeps on reading this sector, until eight of 16 retries are identical, but at maximum one, three or five times (according to the selected error recovery quality) these 16 retries are read. So, in the worst case, bad sectors are read up to 82 times!
Simple enough. If a read request sometimes returns bad data, read everything twice, and then be extra careful if the first two reads didn't match. AccurateRip is the same principle, but distributed – it's a service to which rippers can submit checksums of their ripped audio files. The idea is that if you rip a track and see that a thousand other people got the same bits for the same track, then your rip was probably good.
Exact Audio Copy Download
This article is about what happens with both techniques fail. EAC can't make progress if every single read returns different data, and because it's rare the AccurateRip database only had a single entry