For cinemas, access services equipment needs to be installed for the AD track to be delivered.
AD Headsets
In cinema blind and partially sighted users are provided with headphones so that only they hear the AD track. This ensures that the AD does not disturb other cinema-goers. The headphones play the AD track to the user but also allow the user to hear the cinema sound system to take advantage of the surround sound or other audio environments available.
AD on 35 mm cinema
In September 2001, a system was developed by US based company DTS (Digital Theatre Systems). The AD track was linked to the DTS time code on each reel of film. Consequently, at the start of each new reel, a new section of audio description was triggered, thus ensuring that the film and AD were always synchronized.
Dolby subsequently developed the Dolby Screentalk system, which works by tying the AD to the Dolby time code. A major breakthrough was realized in 2003, when the UK Film Council agreed to partially fund cinema audio description equipment in 78 cinemas around England. These installations kick-started the project and there are now over 300 cinemas in the UK with an accessible screen equipped with either a DTS or Dolby delivery unit.
AD on Digital Cinema
With the advent of digital cinema, AD is now part of the digital cinema package. The description is still transmitted via an infra red headphone system, similar to screens using analogue film. Only those cinemas that have the IR transmission system and the headphone system installed are able to deliver audio description to the audience. The challenge for the industry is to have the audio description track finished and available in time for it to be included on the digital print.
Information for blind and partially sighted people
CEA card could mean cheaper cinema tickets for people with sight loss