Provide the viewers with a transcription of all significant content
Show CC on any visual display
Closed captioning (or CC) is the process of displaying text, such as dialogue and sound effects, on a video screen or any visual display. CC is obligatory for the majority of programming on broadcast TV in the United States, Canada and China, as well as in most Latin American countries.
Synchronization with the video image
CC can be turned on/off by the viewer