Sunday, March 10, 2019

Long Division Tutorial - Making Screen Movies with Voice-Over using Quicktime

Since I have a new iMac and the old one was running slow at the end, I decided to do fresh installs of all the applications.  On the old machine I had Snagit, for screen image and screen video capture.  It's a nice application but it is not free.  Cheapskate that I am, I thought to try the apps built into the Mac OS to see how functional I could be with them.  For still images there is a utility called Screenshot that works reasonably well.  It makes captures as .png files.  And it is quite easy to do an area capture of the right size.  For this functionality, I would rate it on a par with Snagit.  Snagit does have tools to mark up the image after capture.  So I don't want to say Screenshot and Snagit are the same for this.  It's just that the marking up part I rarely use.  (Preview, another utility on Mac which I use to view the captures from Snapshot, does have some marking up functionality, but I've not used it for that.)

In this post I want to focus on video capture.  For that one can use Quicktime, which does talking head capture with the built in camera, audio only capture, or screen video with voice over.  I have experimented with the talking head video and the screen capture video.  In the examples I will show, I will only do the latter, but some of the tricks I will mention were learned from the talking head capture, so I will included those tricks here.  I also want to talk about about the objects that are captured.  The first is an Excel workbook with a tutorial for doing long division.  I would classify it as a dialogic learning object, and it appeals to me at that level, so some of the discussion will revolve around the making and the design of such objects.  I'm guessing that in broad deployment mainly there are old style paper and pencil methods, with textbooks that are not that much different from what I had 50+ years ago.  So one might want to ask whether the learning object is effective and, if so, how it and other objects like it might be created and broadly shared.   I do want to note here that this object requires a real computer, desktop or laptop.  It can be Windows or Mac, but must have a current version of MS Office installed.  It definitely won't work on a phone, regardless of OS, and I think it likely won't work on a Tablet or a Chromebook, even those that claim to run Office.  I haven't tested this to be sure, but I did want to give these caveats before proceeding.

The second example is based on a PowerPoint presentation that is stylized in a particular way.  The default slide size in PowerPoint is in a 16:9 aspect ratio, which is now the desired aspect ratio for recording movies to be posted to YouTube.  So for recording PowerPoint, it's easy to get the rectangular region to be captured in the right proportions.  The capture of Excel that I did was much wider than 16:9.  The reality is that the region where the interesting stuff was going on in the Excel was a thin and wide strip.  By contrasting the two videos one gets a sense of the strength and weaknesses of each approach.

The styling in the PowerPoint is aimed to get the viewer to focus on one line at a time.  Subject matter experts who haven't thought through the issues for the viewer in watching a presentation are sometimes prone to jam a lot of content onto a single slide.  In some cases, it is literally a copy of part of a page in the paper being presented.  This doesn't work for the audience AT ALL!  The actual presentation for my example is extremely simple, with only three slides, text only, no graphics. Though it is often the case that images convey ideas more readily than words, so that in many presentations I've made for the class I teach I try to have little text on the screen (and then give a fuller text explanation in the notes panel) there are some cases where a text only presentation is appropriate.  For example, in this video I work through the math behind the model in a well-known paper by Shapiro and Stiglitz.  As that video seems to have been largely well received by those who viewed it, I would say there is some merit in the style of exposition, though it probably is better when viewed on one's own computer than in a live presentation in a classroom.  I apply the same style to the example here, but there is little complexity to unfold in this case, so I'm only doing it for the sake of illustrating the approach.  It surely would be as good to simply write out the instructions and not use PowerPoint at all.

One can get a pretty good sense about how the Excel Tutorial works, by watching the video below, where a long division example is worked through fully.  Solving a long division problem, one applies a certain algorithm and then does so recursively.  The tutorial is meant to highlight the various steps in the algorithm, as well as to keep track of work done at prior stages.  The feedback that the student gets is real, but still minimal.  If the student has made a mistake, the feedback should help in correcting the error.  One might use brute force methods (try all possibilities till the right one appears) but as this is not for credit, only to aid with the student's understanding, the student should be encouraged to do the arithmetic thinking that is needed to complete the step.  I do want to note that in recording the video, I did all that in my head.  Some students might be more comfortable with pencil and paper on the side. Or they might use Excel elsewhere to do the arithmetic for them.

I originally made the tutorial after watching my younger son do his math homework.  His handwriting was atrocious (just as mine was).  In addition, he treated the paper he was writing on as scarce. so as he was running out of space on a page he would start to jam stuff together in a way that was even harder to read. Relative to that experience, the tutorial gives a clean look as does the record keeping needed in a tidy fashion.  That's probably not enough for people to like the tutorial, but it is not an insignificant benefit.

The real test of whether the tutorial is useful or not is if students used it to teach themselves how to do long division.  I'm a big believer in intrinsic motivation, but perhaps students would need to be assigned some long division problems to work for credit.  Then, if they had the tutorial at their disposal, would they use it or do it by hand?  I want to note a bit of my own reluctance to encourage that use as it might encourage the brute force methods I would hope the students would not try. So here all I can say is that this is a tool for teachers.  Let each teacher figure out how best to deploy it.

Regarding how the tutorial is designed, note that the Excel Workbook actually has two worksheets.  The video is of the Student Version, which is locked.  That is not to hide how things work under the hood.  That is so students don't mistakenly type in a cell with formulas in it and muck up the tutorial in the process.  There is no password on that worksheet so it can be unlocked, if desired.   There is another worksheet with the same content, but there is no fill in the cells (the Student Version has each cell with a white background) and since it is unlocked  one can click in each cell to see the formula that is applied.  To understand what the various buttons do you need to install the Developer Toolbar in the Ribbon (see Excel Help for doing that) and then right click on each button.    Some idea for how the tutorial works might be had by seeing that there is a separate column for each digit in the divisor (six columns in all).  The initial action happens in those columns.  The controls to the right take their information from the divisor columns.

There is some art, then, in visualizing how such a tutorial might be constructed.  I believe it is a teachable skill, so that others might make tutorials for still different algorithmic content.  But, I haven't tried to teach anyone else how to do this.  I can say that it took me a full day (and maybe part of a second day) to do this.  In other words, there is both some imagination required to see how the tutorial might lay out, and then there is a fair amount of time on task to get that done.


Let's now consider the video produced from the Excel tutorial.  It renders quite clearly on my computer but I would say it is rather ugly because of the black bars at the bottom and the top, a consequence of the actual capture being very wide and not very tall. Here are two things to observe about that.  First, if you mouse over on YouTube at the bottom right, it should say Watch on youtube.com.  Click on that and then make sure you are viewing in default view.  If you are, there is no black bar.  YouTube in default view renders the video in the dimension of the capture, not in a fixed sized capture window.  So, if you make irregular sized captures, you can link to them rather than embed them.  (This must be a comparatively new feature.  It used to render the video in a fixed sized window.)  Second, if you click on the cc button you will see caption text in the black area.  In this case, those captions were auto generated by YouTube, rather than manually generated by me, so I won't vouch for them.  Plus, there is still too much black area for the captioned text.  But, if captions were important for your video, for accessibility and for technical content where viewers should see the spelling of the words, then you want captions and some black area below the video to render them, rather than have the captions overlay the video real estate itself.

Let's move onto the PowerPoint video.  It is much closer to the idealized 16:9 ratio, but it is not perfect, because I did it by eyeball techniques only, so there is still a small black line/bar at the top and the bottom of the video.  From my point of view, that's a plus.  It's me producing these things, not some videographer.  I think that instructor created videos should have a home movie element and not look very slick and have high production value.   I hope the video does convey that giving focus to one line of text at a time is helpful to the viewer and makes it easier to follow the presentation.  That was the idea I was trying to communicate.



Let me wrap up.  I will do so by again making comparisons with Snagit.  It has a built in way to force a 16:9 capture area, which would seem desirable based on the previous discussion.  It also has a way to record "system audio" such as music you might add in the background.  That is a powerful feature.  I might still buy Snagit for the new computer in the not too distant future so I can have those capabilities.  But I think the built in tools on the Mac are pretty terrific and one can go pretty far just with them.  So, for now, this cheapskate will opt for that.

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