Legislation on audio description on TV in the United States was introduced in 2010, after setbacks to audio description such as the switch from analogue to digital television, and the resistance of the Motion Picture Association to audio description on TV.
In 2010, President Obama signed into law the Twenty-First Century Communications and Video Accessibility Act of 2010 which restores rules set out by the Federal Communications Commission (FCC) mandating audio description on television.
Audio description is delivered as a second audio stream to your television or set-top box, and can be either 'receiver mixed' or 'broadcast mixed'.
With receiver-mixed audio description, the normal audio stream for the program is broadcast, while the second audio stream consists of the audio description narration only, along with signals that lower the sound level on the primary audio stream so that the descriptions can be heard.
With broadcast-mixed audio description, the second audio stream contains both the original soundtrack and the descriptions mixed into it.
