We've made a screencast to promote Sequence Matrix, a genetic sequence concatenation tool I wrote at the Evolutionary Biology lab at the National University of Singapore. This was my first attempt at creating a screencast, so I learned a thing or two I'd like to remember the next time I make one of these.
This video was recorded and edited on a MacBook Pro using ScreenFlow, a piece of screencasting software I chose after surveying screencast products late last year. The audio files were recorded by Prof. Lohman using iMovie and uploaded to a file sharing service. This means that I got them as individual clips, which were much easier to work with instead of a single, large file which I'd have to cut up myself.
Here's what I'll be keeping in mind the next time I need to make a screencast:
- Use a separate account with minimal decoration: create a new user account on your Mac just for recording screencasts. In this user account, get rid of the status decoration on the status bar in the top-right corner of your Mac screen (you can drag them off by ⌘-clicking on them). Reduce your screen resolution: 1024x640 worked well for me. I think YouTube uses a 16:9 ratio on its videos, so this screen ratio (at 16:10) will be stretched slightly, but it won't be too bad. This also means you're using your entire screen, which really shows off the Mac's gorgeous user interface.
- Get rid of the time: beware of the clock in the status bar (upper left corner) and iCal (on your Dock), which will show the effect of your editing by jumping forward and backward in time. Even worse: record on multiple days, and both these apps will be changing days as well. Longtime Mac users might not realise that recent versions of iCal continue to show the correct date even when not running - the days of iCal Day has, it seems, come to pass.
- Pick a homing point to move your mouse pointer to in between clips. For this video, my homing point was about 2/3rd of the way down from the top of the screen and 2/3rd of the way from the left of the screen. I'd start recording a video clip with my mouse pointer there, and end the clip by moving the mouse pointer back there. That way, the mouse doesn't appear to jump around in between spliced cuts. Another added benefit - if you later decide to rearrange your clips, each video will continue to start and end with the mouse at the same place, so they'll all continue to fit neatly together.
- Use speedups to demonstrate something boring: I'm not so sure about this one, but it's something to think about. The first time we export a file in the video, I sped it up slightly (150% or so faster than usual) so as not to bore the viewers. The second time we export a file, I run it at between 300% to 500% normal speed. That way, the viewers can see what's happening (and realise that yes, it's pretty much exactly what they saw earlier), while also moving swiftly along to the interesting bits. I did this a lot towards the end of the video (during the Nexus and TNT exports), and I'd love to look at it again with fresh eyes in a while and see how it came out.
I'll move these tips into the Creating Screencasts WikiBook when I get the time, but for now please feel free to add your comments, suggestions and complaints on the YouTube video itself or on this blog post.