Buzz
Closed captioning proves beneficial in at least three key scenarios:
- It has greatly aided viewers with hearing impairments.
- It’s also valuable in noisy settings. For instance, a TV in a bustling airport terminal can display captions and remain functional.
- Some individuals utilize captions to improve their English skills or enhance reading proficiency.
Closed captioning is embedded in the TV signal and appears when a special decoder is used, either as a separate device or integrated into the TV itself. This decoder enables viewers to read captions, typically shown at the screen's bottom, explaining what is being said or heard on TV programs. Since 1993, the Television Decoder Circuitry Act mandates that TV sets with screens of 13 inches or larger sold in the United States must include built-in decoders. External decoders are also available for older TVs.
The captions are concealed in the line 21 data area within the vertical blanking interval of the TV signal. If you’re familiar with the article titled How Television Works or the V-chip question, you’ll know about the blanking interval. This section of the signal directs the electron gun to return to the top-left corner of the screen to start drawing the next frame. Line 21, situated in the vertical blanking interval, is designated for captions, along with time and V-chip data. Each video frame can carry two characters of caption information (or specific commands like color adjustments, pop-ups, etc.).
A lot of shows and advertisements now feature captions. Older programs that predate the widespread use of captioning have been updated with captions for their reruns. You can find captioned shows marked with 'CC' in TV guides. If your TV has a built-in decoder, you can enable captions by following the instructions in your TV's manual.
Some programs feature real-time captions. This happens during live broadcasts of events or news programs, where captions appear just a few seconds after the action, showing what is being said. A stenographer listens to the broadcast and types the spoken words into a specialized computer program that embeds the captions into the TV signal. The typists need to be fast, precise, and highly skilled in dictation and spelling.
Other programs display captions added after production. Caption writers use scripts and listen to the program’s audio to insert words that describe sound effects. For example, on a game show without dialogue but with laughter, the caption will read 'Audience laughing.'
- FAQ on closed captioning by advocate Gary Robson
- WBGH's Caption Center
- How Television Works
- question on the V-chip
