Comment by amiga386

CD audio data is indeed lossless data, and has some form of spreading the data physically (CIRC), but has limited error correction. Data CDs have more error correction data than audio CDs, so are more resilient to media degradation, scratches, etc.

When CD audio has errors, more often than not, the CD drive conceals the error -- it interpolates for this unreadable data and doesn't tell the host. Some drives do report C2 errors, but many lie about their capabilities, or have poor implementations.

Secondly, when you ask for CD audio, you can't say "give me the samples from 00:01:23.567 to 00:49:20.211". You can say "seek to 00:01:23.567; start playing; give me the audio samples over ATA as you read them". You can also say "tell me where you think you are on the disc right now". CD drives do not do this reliably, or give reliable answers. Exact Audio Copy is looking to detect this and account for it.

EAC is best used with drives which reliably report wrong locations, i.e. are always wrong by a fixed amount, and EAC can learn by how much by comparing how your drive reports known discs to what's in the AccurateRip database.... but EAC can also work with drives that are unreliably wrong as well, it just has to read the same audio data multiple times over to get a good fix on where that audio really is on the CD.

See https://www.accuraterip.com/ for more details of how CD drives lie to you and let you down