All video or media materials used in classrooms in colleges or universities or for orientation or in-service training need to be open or closed captioned to ensure full information access for viewers who are deaf or hard of hearing.
Closed caption video provides the option of having the captions appear on the screen through a decoder built within the television. Open captioned media does not require a decoder as the captioning is permanently part of the picture and cannot be turned off.
For a good explanation, take a look at George Brown College's Captioned Media and E-Text Policy
E-Text includes traditional print material (i.e. textbooks) produced in electronic file formats such as MS Word, HTML or Adobe PDF. This format can be adapted to the users' needs such as Braille, large print or audio files with a variety of software and hardware.