Editing CD ripper (section)

==Difficulties in obtaining accurate reproductions==
Ripping a CD to audio files that will faithfully reproduce the same CD if burnt again is not trivial. Such a rip (along with a [[Cue sheet (computing)|cue sheet file]] and other metadata describing the layout of the files on the disc) is sometimes referred to as an "accurate", "perfect" or "secure" rip.<ref>{{Cite web |date=2016-05-28 |title=DAD/Rip – Thomas |url=https://web.archive.org/web/20160528213242/https://thomas.apestaart.org/thomas/trac/wiki/DAD/Rip |access-date=2025-03-31 |website=web.archive.org}}</ref> Some CD ripping software is specifically intended to provide accurate rips, including [[CloneCD]], [[Exact Audio Copy]], [[cdda2wav]], [[CDex]], [[cdparanoia]] and [https://github.com/whipper-team/whipper whipper]. There is also a reference database with [[Hash function|hash values]] of known good rips that can be used to confirm a successful rip and in some cases calibrate parameters for a CD drive.<ref>{{Cite web |title=AccurateRip |url=https://accuraterip.com/ |access-date=2025-03-31 |website=accuraterip.com}}</ref>

In the context of [[ripping|digital audio extraction]] from [[compact disc]]s, '''seek jitter''' causes extracted [[Sampling (signal processing)|audio samples]] to be doubled-up or skipped entirely if the Compact Disc drive re-seeks. The problem occurs because the [[Red Book (audio CD standard)|Red Book]] standard does not require block-accurate addressing during seeking.{{efn|Due to additional sector level addressing added in the [[Yellow Book (CD standard)|Yellow Book]], [[CD-ROM]] data discs are not subject to seek jitter.}} As a result, the extraction process may restart a few samples early or late, resulting in doubled or omitted samples. These glitches often sound like tiny repeating clicks during playback. A successful approach to correction in software involves performing overlapping reads and fitting the data to find overlaps at the edges. Most extraction programs perform seek jitter correction. CD manufacturers avoid seek jitter by extracting the entire disc in one continuous read operation, using special CD drive models at slower speeds so the drive does not re-seek.

Properties of an optical drive helping in achieving a perfect rip are a small sample offset (at best zero), no [[jitter]], no or deactivatable [[cache (computing)|caching]], and a correct implementation and feed-back of the C1 and [[C2 error|C2]] error states. There are databases listing these features for multiple brands and versions of optical drives. Also, [[Exact Audio Copy|EAC]] has the ability to autodetect some of these features by a test-rip of a known reference CD.<ref name="daefeatures">[http://www.daefeatures.co.uk/faq.php DAE Drive Features Database - FAQ] {{Webarchive|url=https://web.archive.org/web/20060116031732/http://www.daefeatures.co.uk/faq.php|date=2006-01-16}} (2007)</ref>