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Making a lecture video

Topics/tags: Teaching, computer science

Today I made my first lecture video, or at least one of my first lecture videos. I don’t tend to lecture in class [1]; I’d much prefer to run a more interactive or Socratic session, or to run a workshop-style class. And I’ve already expressed my distaste for making talking-head videos. So why did I make a lecture video? Well, I’m guest teaching for a colleague, and that colleague has flipped their classroom; class time is devoted to working on problems, out-of-class time includes an opportunity to watch the lectures that would traditionally occupy class [2].

I’ve been thinking about the content for the past few days. It’s a topic I’ve taught a few times [3]. But I’ve always taught it interactively: Okay, what would you try here? What other alternatives do we have? What else should I be thinking about? And it’s a lot of content: Students learn four techniques for solving a certain kind of problem [4] and one technique for checking their solutions. There’s math involved. And one of the techniques involves drawing.

Fortunately, I had technological resources at hand: I’d purchased a slightly old copy of Camtasia during a Humble Bundle promotion [5]. And I have a Wacom Intuos Wireless Graphic Tablet which I got in case I wanted to make screencasts for the new CSC 151.

My first big decision was what to use as the whiteboard. Traditionally, I use a text editor during class for everything but the diagrams, and I draw the diagrams on the physical whiteboard [6]. That strategy seemed less appropriate here. I debated setting up a complete slide deck, which I know many people use. But slide decks feel less interactive. I know that I’m already lecturing, but there’s only so far I’m willing to go. Plus, my colleague uses a digital whiteboard for their video lectures.

I thought I could set up a framework of blank slides in Google Slides and then type and draw on those. The scribble tool seemed to provide an appropriate way to draw. And text areas support writing [7]. The slide titles provide the students with some context while still allowing me to type and draw while I talk. And I can put the script [8] in the notes area.

Things seemed to be going okay. Then I got to the point where I wanted to draw a lot. And, well, it didn’t work as well as I thought. You need to re-select the scribble tool for each thing you want to draw. And I also needed text in the middle of the diagram. It was clear that Google Slides would not work. I thought about using Photoshop for that portion. But Photoshop is too cumbersome. I tried using two different PDF editing tools. Preview likes to convert sketched lines to curves, and not always the curves I’d expect [9]. PDF Expert seemed to meet my needs, other than the inconvenience of switching from Google Slides to a PDF and back again.

However, because I have a Retina display [10], Camtasia wants me to use a relatively limited space on the screen [11]. I found it hard to write legibly in that area. I’m pretty sure that with some effort, I could have figured out how to make everything work, such as by changing the correspondence between the tablet and the screen. And, even at the best of times, my handwriting and drawing are somewhat mediocre. I also liked having the script in my Google Slides.

So I decided to make a series of slides showing the gradual expansion of a tree. While it took a lot of time to make the slides, that strategy worked surprisingly well [12].

All that was left was to record myself speaking and typing. I identified a variety of mistakes, including one I missed the first time through. I’m glad that Camtasia makes it easy to cut and join pieces [14]. The video was long enough that I thought about splitting it into four or so separate short videos [15]. But, well, that would require more time and effort to frame each section. That’s a kind of task for another day.

Once I’d put everything together, I listened to some of it and, when appropriate, updated the script to match. I didn’t have time to go through everything, but I’m pretty sure I got to most of it.

Since the video is not captioned [16,17], I can’t share it with you. But if you want to see the slides, most of which I filled in live, they are available at

Will I make other lecture videos? I don’t particularly like either lecture videos or the process of making them. Given a choice between a video and a textbook, I’ll almost always choose the textbook. Given a choice between giving a lecture and forcing students to participate in an interactive recitation, I’d prefer to run the recitation. Making a video that meets my standards also takes a lot of time and effort. But I’ve seen that some students find them helpful. For example, it’s nice to be able to rewind when you don’t quite catch something. So I’m going to try to make some short videos to go with the new CSC 151. We’ll see how it goes.

[1] I do, however, pontificate from time to time.

[2] I use a similar strategy, except that I ask them to read outside of class, rather than to watch a video. My colleague is more generous than I and gives students the additional option of a video lecture.

[3] Solving recurrence relations, if you care.

[4] More accurately, the learn three new techniques; they should have seen one in the past.

[5] $20 is a much better price than $249. Of course, it’s unlikely that I would have purchased it for $249.

[6] In many cases, I use ASCII art for the diagrams. I like having an electronic record.

[7] Well, typing.

[8] I’m not fond of reading from scripts. However, I do anticipate captioning the video. Scripts make captioning much easier.

[9] Or was that Google Slides? I forget.

[10] I’m pretty sure that Retina is a trademark of sorts, and should be capitalized.

[11] I didn’t think about attaching an external monitor. Or perhaps I didn’t have one available.

[12] Well, it worked surprisingly well from my perspective. We’ll see what the students think.

[14] I hope I cut out all of the profanity that happened when I muffed a line or statement.

[15] If I recall correctly, there’s evidence that videos longer than six minutes or so are less successful.

[16] Or not yet captioned.

[17] Since the full script is available with the final slides, I am comfortable that I am providing an appropriate alternative for those who would benefit from a captioned video.

Version 1.0 of 2018-09-27.