Editing Constant angular velocity (section)

==Uses==
[[File:Laserdisc CAV.jpg|thumb|Constant-angular-velocity (CAV) [[LaserDisc]], showing the NTSC field setup and individual scan lines]]
[[Gramophone record]]s have always used CAV, including [[Capacitance Electronic Disc|CED]]s which provide video signals.

Some high-speed CD and DVD drives can use CAV.{{specify|date=April 2012}} It allows for shorter [[access time]]s because the rotation speed (angular velocity) does not need to be changed when the laser seeks across the disc, similarly to the [[Disk read-and-write head|magnetic head]] of a [[hard disk drive]]. With a given angular (rotation) speed, the linear speed at the outermost track is nearly 2.4 times as fast as that of the innermost track.

CAV was used in the [[LaserDisc]] format for interactive titles; it was also used with [[special edition]]s of certain films.<ref>{{cite web| url= http://www.voyagerco.com/criterion/catalogpage.cgi?ghostbusters| archiveurl= https://web.archive.org/web/19970213145931/http://www.voyagerco.com/criterion/catalogpage.cgi?ghostbusters | archivedate=1997-02-13| title= The Criterion Collection: Ghostbusters| publisher= Voyager Media Store | work=voyagerco.com| accessdate=2012-04-30}}</ref> CAV allowed for perfect still frames, as well as random access to any given frame on a disc. Playing time, however, was 30 minutes on each side (these discs are also known as "standard play"), as opposed to 60 minutes on each side for CLV-based discs ("extended play").

CAV is used with the [[Nintendo optical disc|Nintendo GameCube Game disc and Wii Optical disc]], the [[Xbox (console)|original Xbox]] discs, and Sega's [[GD-ROM]].{{citation needed|date=April 2012}}

=== Partial constant angular velocity (P-CAV) ===
If the used media (e.g. [[DVD-RAM]] variants) has a linear (writing) speed limitation that can not be attained with physically supported angular (rotation) speeds at the inner edge of the recordable area, the disc writing can start off with a constant angular velocity, until the increasing linear velocity has reached the writing speed limitation of the disc.

At that point, the drive transitions into writing with a constant linear velocity.<ref name=P-CAV>[https://qpxtool.sourceforge.io/glossar.html#p_cav QPxTool glossary: P-CAV (partial constant angular velocity)]</ref>
<ref name="cdrlabs-SE208">{{cite web |title=CDRLabs.com - Samsung SE-208GB Portable 8x DVD Writer - Reviews |url=http://www.cdrlabs.com/reviews/samsung-se-208gb-portable-8x-dvd-writer/print.html |website=CDRLabs |accessdate=9 August 2020 |language=en-gb |date=2014-12-03}}</ref>