Captioning plays an essential role in this objective. The verbatim captions are used for several purposes. Captioning is used to structure and markup the video. This structure is then used to navigate within the video and to condense or expand the material. For example, if a learner wants to go back to every mention of a specific term, the caption would be used to sort the start time codes for the segments.
Standard captions are limited to text and restricted to either the bottom or top of the screen.
By allowing multimedia overlay captioning, comic book conventions can be adopted to indicate the source of sound. Color, animation and graphics can be used to indicate affect, music and non-speech sounds. Captions can also be used to label visual objects or highlight a part of the video frame. Most importantly the captions will be used for hyper-linking. Thus if the learner wants more information about a term, a definition, background material, related material or an interactive exercise that further illustrates a concept, they would click on the term or phrase in the caption which would pause the video and take them to the supportive material.