A secondary soundtrack that the user can select and play on top of the original soundtrack: this method can be implemented in two significant ways. First, and because some devices don’t allow two soundtracks to play at the same time, the audio description is played along the original description, and it contains the descriptions only. Second, with the devices that do allow two soundtracks, the original soundtrack is removed and replaced with a new soundtrack that contains the audio descriptions.
Creating original audio descriptions for the movie: It is a method that involves adding the audio description to synchronized media by using a second version of the film where a single track containing the original soundtrack along with the audio descriptions is created.
Creating extended audio descriptions for the movie: It is a method that involves a prolonged version of the movie with extended audio descriptions. The problem with audio description is that they have to explain a lot of things in a short time as in between dialogues. In this case, a version of the movie is created with extended audio descriptions and also one more version without the descriptions. Some devices will allow turning the descriptions on and off.