Captioning is the process of audio content transformation into textual content. Auditory contents from television programs, film, video, CD, DVD, and other live events are converted into text and displayed on the monitor or user screen. Efficiency in the captioning service could be identified through the specific representation of audio content such as sounds other than verbal text as captions. Also, an efficient captioning service should include synchronized appearance of textual information in line with the correct timing, and equivalent content is displayed similar to the audio content. Factors such as timeliness, accuracy, completeness and efficiency are considered in captioning. Also, captions should also be in line with the corresponding visuals.