More information about captions

Captions help people understand the soundtrack of a TV program. They recreate a soundtrack in text so that it may be read by viewers. Closed captioning does not interfere with normal viewing.

Captions are coloured and positioned on the screen to show each character’s speech. Sound effects, music and other audio cues are also incorporated in captions to ensure all relevant information is available to the viewer. This is the main difference between captions and language subtitles, which just show a translation of dialogue into English.

Many deaf and hearing-impaired viewers are familiar with current captioning on analog television.

Captions are normally ‘closed’ to viewers but can be accessed by those who need them through use of either an analog TV, or VCR, with teletext capability.

Who uses captions?

• Deaf and hearing-impaired people

People who rely on captions to follow the soundtrack on television or videos.

• People learning English

Many language schools use captioned videos and television to help teach people spoken English. Students can follow a soundtrack while reading the captions and listening to the pronunciation of words.

• People in noisy or common areas

Captions can be used by anyone who is trying to watch a program or video in a noisy environment, or where the volume cannot be adjusted. Captions are useful anywhere there is noise—shopping centres, shows, banks, pubs and clubs.

• Anyone

Some people use captions to watch their favourite programs and talk to friends on the phone at the same time.

Captions on digital television

The DVB standard provides for captioning using two different systems—DVB Teletext and DVB Subtitles.

DVB Teletext resembles World System Teletext used in analog broadcasting in that only text information is carried in the data stream. This makes it an efficient way to carry captions as it has low bandwidth requirements. However, fonts are limited and dictated by the display device.

DVB Subtitles are bit-mapped graphics. Their appearance is controlled by the author in the same way as subtitles on DVDs. While a higher data overhead is required, the readability of DVB Subtitles is far superior to DVB Teletext.

Australian captioning requirements on digital television

Australian free-to-air television broadcasters are required to caption all English language news and current affairs programs, as well as all programs broadcast during prime time (6.00pm to 10.30pm).

Receiving equipment

Caption decoding and display is a requirement for compliance with the Australian Standard for television receivers (AS 4933). Industry compliance with Australian standards is not mandatory.

For more information about captions, visit the Media Access Australia web site at www.mediaaccess.org.au

• Document ID: 80896 |
• Last modified: 24 October 2008, 2:06pm