The Basics of Closed Captioning

Closed captioning refers to the written dialogue of a film or show that displays on screen as it corresponds to what is being said.  Its main purpose is to allow people with hearing disabilities to follow the dialogue.  With that said, it is also commonly used in loud public places such as gyms and bars.  The basic features of closed captioning include:  white block letters against a black background, monospaced letters, a limited set of characters and lines, and the option of being turned on or off.  The word "closed" in the term refers to the fact that certain electronics are required to make the captions visible and therefore are not seen by all viewers, only those who opt for them.  Closed captioning is not to be confused with subtitles.  The difference is that subtitles are preprogrammed into a film or show and are seen by all viewers.  They are used when viewers can hear the actor(s) speaking but cannot understand the language and may be continuously displayed throughout the entire film or show, or only in particular sections.  Though captions may seem rather easy to include, the processes involved are actually somewhat complicated. 

The two general formats of closed captioning are off-line captioning and on-line captioning.  Off-line captioning means that the captions are created and incorporated after the product has been recorded.  A specialized computer program is used by trained caption writers (stenographers) who carefully watch and listen to the dialogue as they enter the information into a computer, while also inserting time codes and position codes to control exactly when and where each caption will appear on the screen.  Each caption must be placed precisely so that they match up to every lip movement, the caption boxes match in each shot, and avoid hiding any important visual information a shot may have. Captions created offline can either roll up or pop up on the screen.  As you would assume, roll-up captions roll up the screen line by line, up to three lines at a time.  Pop-up captions pop on and off the screen in a rectangular box, include 3 lines as well, and usually describe sounds other than words.  Because the process is very tedious and time-consuming, they are by far the most expensive to create.  Factors such as speaking rate and how often the scenes change also must be taken into account.  However, offline captions are the least likely to have any mistakes given that the writer is able to go back and edit them as many times as he/she wants.

On-line captioning, on the other hand, is conducted simultaneously with a broadcast and usually appears in a scrolling format.  The three types of on-line captioning include: real-time captions, live-display captions, and teleprompter captions.  Real-time captions are the captions you see during live news, sports, and other live events.  Live-display captions are typically incorporated into a program that was previously live but is to be broadcasted again.  In this case, the stenographer is able to review the real-time captions that were applied and make any necessary corrections.  Lastly, teleprompter captions are used when the script for an event has been prepared ahead of time. As the speaker reads the script, it is simultaneously encoded onto a screen and broadcasted.  Obviously, real-time captions and teleprompter captions require a highly skilled typist who can type extremely fast while making minimal mistakes, if any at all.