Audio post production is the general term for all stages of production happening between the actual recording in a studio and the completion of a master recording. It involves sound design, sound editing, audio mixing, and the addition of effects.
Audio post production usually refers to the post-production of audio that is synchronized with video. This applies to TV, cinema, and commercials. One major aspect of audio post production is the use of ADR, or automatic dialogue replacement. Sometimes the original, or production audio, lacks in performance or quality, and the actor or actors are brought into a sound studio to record some or all of their dialogue from the project. Other elements such as foley, music, and voiceover, are also added during post production.