We are all familiar with the recording and videotaping of lectures. What is suggested, here, however, is not the mere videotaping of a talking head, but an interactive video which requires the student to do something, normally to complete a task in a workbook, which is then self marked, using a second video. The presentation consists of a session of appropriate length in which the concept is explained, and examples given, as would be done in a normal lecture theatre. Students then open their workbooks and attempt the problems presented or write an explanation, dealing with a scenario, etc. A second video is then shown, giving the range of potential answers, and explaining the method of working.
Students mark their own work, and perhaps undertake other tasks as presented in the video.
At the end of the session, the workbooks are collected for inspection, firstly to see that the tasks have in fact been completed, and secondly to assess the general progress of the group. The workbooks would eventually be returned for revision, etc, before assessments and exams. No one suggests that it is as good, but it is certainly far more affordable. The class receives pre-class reading material in preparation, and after the lecture is given a test, on disk, to assess the depth of understanding. While this can be done individually, there may be considerable advantage in working in small groups, where one person may be able to support the others.