My job responsibilities were recently expanded to recording some screencast type videos for our company. Screencasts can seem intimidating if you haven't ever done them before, but in reality, they've gotten incredibly easy to do, and to do well.
First things first: You must have a good microphone to make a good video. No ifs, ands, or buts. A good microphone can make a bad video an ok video, and a bad microphone can make a great video terrible. And for the record, a set of Apple earbuds with the little mic thing doesn't count. Ever.
Now, that's not to say that you need a full studio setup with a mixer and the whole nine yards. I use a Blue Microphones Yeti, which is a really affordable microphone that sounds great. There are all sorts of fantastic resources for people who want to record (see things like Dan Benjamin's excellent Podcast Method), but for what you'll likely be doing, anything more than a good USB microphone is likely overkill unless recording is going to become your full-time job.
It's no secret, I'm kind of a Mac guy. And for audio, I tend to find that I generally prefer the tools that I have available to me on the Mac as well. While I record the Sourthern Fried Security Podcast on my Windows computer at home, that's mostly because Martin does all the heavy lifting with editing and recording, and I just need something that I can fire up Skype on.
With all that said, I'm aware there are some good tools on Windows (Camtasia Pro is something that I have had experience with in the past), but I prefer to do screen recordings on my Mac, and it continues to get easier as time goes on.
A big part of why it has gotten easier is QuickTime. Specifically QuickTime's Screen Recording functionality. While it's not perfect, it's incredibly easy to open QuickTime, select "New Screen Recording", select your microphone and go. Since it's natively capturing at full screen resolution, it's easy to make sure that the video part of your recording looks good.
There are two main ways to go about audio for screencasts. First, there's the "single take" method, where you're using QuickTime to record the audio along with your video. It requires you not to mess up, but if you pull it off, you don't have to do any additional processing, just export the video and you're good to go. If I'm under a time crunch or just doing something quick, I tend to use this method because it's easier.
However, the other way is to record audio and video separately. Now, this is kind of a new way of doing things for me, but it's preferable if you have a script that won't be changing. My preferred method is to record using GarageBand because it has some nice presets for vocal recording, but Audacity would work just fine for this too. Once you record your audio, however, you'll have to pull the video and audio into iMovie in order to sync everything up, which I find can be a little painful at times.
So you've chosen your tools, you've got a mic, and you're about to click record. Stop. If you don't have a full script of what you're going to say, you're going to have a bad time. Especially if you're doing single take recording, not having a full script fleshed out will shoot you in the foot over and over again. On the bright side, though, if you are doing a video for a company, having a written script can help you solicit feedback easier.
When it come time to record, having a script in front of you will go a long way in helping you stay on track while you record. I like to put the script on my iPad and have it next to the microphone as I record, but that's just my personal preference. For reference, this is what my recording setup usually looks like:
Once you've gotten your recording done, it's a simple matter to pull all the pieces into iMovie, make sure it lines up, and then export straight to file or YouTube, wherever you need the file.
This isn't a full walkthrough of all the steps, and inevitably something will go wrong as you try to record, but this should at least give a starting point of how to record screencasts, as well as some of the equipment and software that can make your life a little easier.