[1][2] A typical candidate for an undub is a Japanese game which has been published in the United States, with voice acting dubbed in English and text content translated into English, but lacking an in-game option to use the original Japanese audio.
The process of undubbing consists of identifying the location and format of the relevant audio content in both the localized and the original versions of the game, then grafting the audio data extracted from the original language version into the localised game.
Oftentimes, dialogue will be completely rewritten in translation, which prompts some to do a total or partial retranslation of the game in order for the displayed text to fit the actual context of the audio content.
Content present in the original game, but cut in the process of localization (due to reasons such as censorship, or, in some cases, a lack of time) may also be restored in an undub.
In the west, on the other hand, voice localization projects usually have smaller budgets, and as such, do not have as professional a market as the Japanese one.