Captions are prepared ahead of time and text is as accurate as timed and placed captions.
Logical line breaks, speaker identification and speaker change symbols are inserted and non verbal cues are added to enhance understanding of the program. A stenocaptioner uses a special stenographic keyboard to type as many as 250 words per minute. A computer translates the steno into English text, formatted as captions. The caption data are then sent to an encoder and inserted into line 21 of the video signal. This is the only method available to caption a live, unscripted program.