Captioning is the on screen transcription of the audio portion of a commercial, television program, film, music video, or any other on screen program, of any relevant audio i.e. speech, sound effects, music, speaker identifiers, etc. Captioning is used when programming sound is inaudible (muted or when background noise is present), or if a viewer has hearing impairments.

Captioning can be either open or closed. Open captions are a burned in to the program, making them always present. Closed captions can be toggled off and on by the viewer based on the viewer’s requirements.

Closed captions are required in a minimum of 90% of all broadcast programming in Canada by the CRTC.

Captions created for broadcast are bound by certain limitations and guidelines (characters per line, formatting, text size etc.) in an effort to provide consistency and appropriate read times for viewers.

Subtitling is the on screen transcription of speech/dialogue and differs from captioning in that it portrays only the speech/dialogue portion of a program, and is primarily used to represent foreign languages, although subtitles are also used to represent the native program language as well.

Subtitling can also be burned into a program, or toggled on and off at the discretion of the viewer.

Subtitling is also more diverse than captions as they are not limited by the same guidelines, and can be presented in different fonts and sizes, without character per line limitations.