Audio and video can be used online for lectures, demonstrations and other engagement purposes.
It is easy to surmise that an online reproduction of a lecture is just making a recording of that lecture and putting it online. An alternative would be to examine the objective and purpose of the lecture and then decide on the best online tool available to transmit the information.
Due to accessibility limitations, sometimes large quantities of audio and video are not suitable for online delivery, so use them only when they work best. Audio and video are very helpful in introducing a human dimension to the course, demonstrating a skill or concept, illustrating unique situations and conveying emotions.
URL: http://vudat.msu.edu/audio_video_animate