Before HDTVs were the standard screen for home consoles, calibration options in games were more rare and usually less featured than today's HDTV consoles. HD monitors can have anything from hardly any delay between the screen getting the signal and outputting it - for example, a computer monitor - or anything up to extremes of 300 milliseconds or more of delay in certain HDTVs. Extreme delay numbers in HDTVs are usually caused by post-processing to improve the image quality. Processing the frame takes time, delaying input-to-output time. This delay can typically be reduced by setting some HDTV models to "game mode", or manually turning off post-processing options one-by-one in the TV's settings.
While viewing TV or non-interactive video (the viewer does not have a frame of reference for when the picture "should" appear) or slower or non-rhythmic games (the viewer can forgive a slight delay between pushing a button and getting response, and games are usually designed around some degree of lag) are typically no issue for the user, rhythm games where a sound or cue on the screen must be paired with pushing a button on the controller within a given timing window can become unplayable if the timing window is unpredictably moved away from the note.
"Guitar Hero" Era Rhythm Games
As HDTVs became more popular, calibration options in games where such sync is needed became more full-fledged. In the first Guitar Hero game in 2005, as well as the second game from 2006, calibration was simply performed by having the player play back a pattern of sound cues synced with on-screen blobs passing a target. As both of these games were originally designed for the Playstation 2, where a minority of the user base would have had HDTVs, having only this option is understandable.
Having trouble hitting notes? Try using the Calibrate Audio Lag tool in the Options menu.
Guitar Hero 3 loading screen alerting users of the feature
But what would happen if the user had different delay for sound input and video output? This could happen if the user separates audio and video before it enters the TV, as happens in the case of an audio reciever, or if the HDTV simply does not try to sync audio to the post-processed frame.
To solve this problem, modern Rock Band games - by the same developer as the first two Guitar Hero games - have separate options for audio and video calibration, as well as the possibility to calibrate to negative lag values in addition to positive ones, should the user so desire. With Rock Band 2, an attempt was made to eliminate manual calibration alltogether by adding light and sound sensors to the game's bundled instruments and adding a mode where the user holds an instrument up to the screen to have the game calibrate automatically. How functional this feature was seemed to vary much from one hardware configuration to the next.
Neversoft-era Guitar Hero games, starting with the third game and leading on until the seemingly last home console game of the series, Warriors of Rock, separated audio and video calibration starting with three, but mostly stayed at that level of complexity, moving around the surrounding presentation. From Guitar Hero 5 on, the player could try playing sample notes using the actual game's fretboard UI next to the calibration screen to test their calibration. A feature Guitar Hero 3 retained from the previous two Harmonix games was the ability to calibrate lag in the middle of a song - this would allow for a similar way to test a quick change in calibration.