Editing Audio description (section)

==Operation==
Broadcast audio description is typically delivered via an alternate audio track, either as a separate language track containing the narration only (which, if the playback device is capable of doing so, is mixed with the primary audio track automatically, and can have separate volume settings), or on a secondary audio track pre-mixed with the primary track, such as a [[secondary audio program]] (SAP).

Many [[video on demand]] (VOD) and streaming platforms host separate assets for the audio-described media, with the soundtrack pre-mixed. Despite AD typically being presented as something that can be enabled (as with [[subtitles]]), users can encounter problems when trying to turn AD on or off because the underlying media version they require is unavailable.

In movie theaters, audio description can be heard using DVS Theatrical and similar systems (including DTS-CSS and Dolby Screentalk). Users listen to the description on a [[wireless headset]].{{citation needed|date=December 2014}} Audio description is stored in the [[Digital Cinema Package]] as "Visually Impaired-Native" (VI-N) audio on Sound Track channel 8.<ref>{{Cite web |title=Accessibility & The Audio Track File |url=https://cinepedia.com/accessibility/accessibility-the-audio-track-file/ |access-date=14 November 2023 |website=Cinepedia}}</ref><ref name=":22">{{Cite web |date=18 May 2020 |title=D-Cinema Packaging — SMPTE DCP Bv2.1 Application Profile |url=https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9161348 |access-date=14 November 2023 |publisher=[[The Society of Motion Picture and Television Engineers]]}}</ref>

[[File:Audio describer in live theater.jpg|thumb|An audio describer working in a live theater. A small mixer and transmitter are visible, and the lit stage can be seen in the distance.]]
In live theaters, patrons also receive the description via a wireless device, a discreet monaural receiver. However, the description is provided live by describers located in a booth acoustically insulated from the audience, but from where they have a good view of the performance. They make their description which is fed to a small radio transmitter.<ref name=VisionAustralia>{{cite web
 |url = http://www.visionaustralia.org/living-with-low-vision/learning-to-live-independently/sport-recreation-and-the-arts/enjoying-theatre-museums-galleries-and-cinema
 |archive-url = https://archive.today/20130416024445/http://www.visionaustralia.org/living-with-low-vision/learning-to-live-independently/sport-recreation-and-the-arts/enjoying-theatre-museums-galleries-and-cinema
 |url-status = dead
 |archive-date = April 16, 2013
 |title = Enjoying theatre, museums, galleries and cinema
 |publisher = [[Vision Australia]]
 |location = Australia
 |access-date = 10 December 2012
}}</ref>