A pitch shifting effect in which a musical source of a varying or random pitch is forced to a specific pitch. It has been implemented by several software vendors in the form of a DAW plug-in, in which it usually processes previously recorded tracks, although some versions are capable of working in real time. It is commonly referred to as "autotune", after the name of the most popular plug-in of this type, "Auto-Tune", which is a registered trademark of Antares Audio. It is generally marketed as a producer's tool for "saving" recording takes by fixing naff notes that were sung or played by the performer. (This use of "autotune" is not to be confused with the synth function Auto tune.)
In popular music, it has become fashionable for producers to use pitch correction to bring the voice of a singer to an exactly tuned pitch. Although the effect can do that, depending on how much correction needs to be applied, it produces an unnatural effect commonly referred to as "robot voice". This stems from a combination of munchkinization by the pitch shifting, and the pitch correction being used to hold the singer's voice to an unnaturally exact and unvarying pitch, more so than a real singer is capable of singing. There has been a tendency among pop singers for the performer to put less effort into getting a good recording take, and instead rely on the producer or engineer to fix the take with pitch correction, so that it becomes a crutch for the singer. But usually, when this is done, it is obvious in the recorded output. Due to these factors, pitch correction has become a cliche in popular music in the decade of the 2010s.
Pitch correction does have more creative uses. Some producers have intentionally used the robot-voice effect by having the singer purposely sing off key into the pitch correction; the resulting effect is somewhat like using a vocoder. Another technique is to have a singer sing at a constant pitch, or play an instrument at a constant pitch, and then use the pitch correction to "play" the desired melody (a sort of resynthesis).