To make it easier for users to listen to an audio alternative at the same time as watching a video, it is helpful to provide an option within the video player that allow users to replace the audio track of the video with audio alternative. Because the audio alternative will have been synchronised with the video, it prevents it from from obscuring (or being obscured by) any audio that is already in the video (e.g. loud sound effects).
Some video players allow alternative audio tracks to be selected, either from a button within the webpage content or within the user preferences of the video player. Alternatively, separate players could be used, with each one presenting a different audio track with the same video content.
No example is available.