Yesterday and earlier today I made some more content for The Economics Metaphor, my site for teaching Economic Principles/Intermediate Micro. Some of what I did was a screen capture movie of some Excel spreadsheets I had designed with my voice over. Thinking that others might like to give it a try, here are some of the tricks I used to get this thing produced.
First, note that Camtasia only does closed captioning if the output is Flash and at this point I've come to concluded that the move itself should be in .flv format, because it performs better and makes smaller files than .swf format. You can do open captioning (a movie with subtitles that are always there) in other formats and perhaps there is some virtue in doing it that way. But I'm going to assume most people would prefer closed captioning if they could deliver it.
Next, when Camtasia does this the captioning background is translucent. That background overlays the video. Based on experimentation, I've found that video itself should have a plain background where the captioning can appear - otherwise it looks noisy and the captions are hard to read. So I captured my video accounting for that.
Then, I want this to work reasonably well on a computer screen that is 1024x768 in resolution. And I'm making the video so it appears in my blog with two columns. The left is the main column where the video appears. The right is the sidebar column. This puts some additional limits on video width. If you were to design a video for its own stand alone page, you'd make it a little wider. I'll show where that occurs in the process.
The region I capture is 640x480. The Excel piece is 640x360 and right below it is background screen that is mono color of sixe 640x120. So there is some discipline in the size of the region that is captured where the action takes place. Those who make Tablet PC movies capturing their own writing might bear that in mind. When the movie is actually produced I shrink it slightly so it renders as 600x450. This is to fit in the blog. This step would be omitted if the video had its own page. If you want the video to render in the browser without having to scroll down to see the player and accounting for the fact that with several Tabs open and possibly a bookmarks toolbar the browser header can take up a lot of vertical space, you can't have a taller video on a 1024x768 screen.
Now let's talk about the captioning itself. (See the image below.) After experimenting with other alternatives, I've opted for 45 characters per line and two lines of text per screen as the rule. I don't always speak in short sentences or pause in the right places, but I think 3 lines of text is daunting as is too much text on any one line. So what I've got is a reasonable compromise. Also note that I put line space between the text on two different screens. It is rather frenetic to put the timings in as the movie plays. The line spacing makes that job easier.
That's pretty much it. My sense is that while we are being pushed to caption by our accessibility folks for any technical content students will really appreciate the captioning and students who are not native in English will likewise appreciate the captioning. It's really not that hard to do. And if the movies aren't too long, not that much work.