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Here is my quick guide to lecturing using a green screen, or, superimposing your face/body over a presentation or other media. All you need is a couple pieces of free software and a little practice.
It is important to say that NONE OF THIS is necessary. You could deliver a great course filming in front of a woodpile. The last thing we need to do is make this hell called COVID a competition over visual presentation. BUT, if you have the capacity, I think it is a nice tool.
Why put your head or body over presentations? First, it allows you (like a weatherperson) to gesticulate or point, which is helpful when using images, maps or video. Second, there is a reason that nearly every live streamer includes their face onscreen - it creates a connection.
Sidenote...if you are not aware that there is an entire culture of people playing video games live in front of an online audience, Twitch will blow your mind. Millions of viewers, tons of competition, and lots of lessons on creating a connection between presenter and viewers.
So, what you need to pull this off is 1) a green screen (see earlier tweetstorm), 2) a web camera or phone camera, 3) software to create the "scene" with you over your presentation or media, and 4) software to capture the video.
The software to use here is Open Broadcast Software (or OBS). It is free, open-source, cross-platform, and extremely well-supported.
https://obsproject.com/
https://obsproject.com/
When you install OBS, it will ask you whether you want to run the Auto-Configuration Wizard. Yes, you do. It will automatically determine your hardware/software capabilities and the best recording resolution.
Next you will want to allow access to your microphone (it will ask you automatically), and add a video capture device (i.e. your web camera.) See image series below.
Next, you want to right-click on your camera source (I renamed mine "Web Camera") and click on "filters." You then want to press the "+" button under "effect filters" and add a "chroma key" filter. I call mine "green screen." There are a bunch of options here to tweak the filter.
I am now a floating body over a black screen. Progress! You will still notice that I am in a box, though. More on that later.
Next you will want to add your slides behind you. To do this, you need to press the "+" button on "sources" again, and add a "display capture" source. This is if you have your slides projected on a second screen. If you only have one screen, you can do a "window capture" instead.
Now you just need to reorder your windows by right clicking on the box where your head should be, and bringing it to the top. And, presto, you have your image over your slides!
As I advance my slides on my second monitor and talk, the OBS captures the video camera image (my head) and the background replacing the green screen (the slides).
What about actually creating a video? You can do that in OBS too. First, click on the "settings" button below "controls" and set your video format. Then, press "start recording" and you are on your way. OBS will capture your web cam, audio and background and create a single file.
I made this goofy video to show you how it all turns out!
You don't have to use OBS to record, though. If you prefer, you can use something like Camtasia or even Zoom and just record your OBS window. The key is that the OBS is creating the effect, and you can use whatever software you want to capture it.
For those who asked for it specifically - @WeedenKim, @soci_MaryC and @Thad_Miller - please let me know if you have questions or need more explanation. It really is easy!
