A nice combination of applications that can be used to create and edit your screen recordings on a Mac OSX is QuickTime Player and iMovie. I had tried doing my editing in Adobe Premiere CS4 but was unable to get a satisfactory level of video quality for my final export. No doubt with a bit of tweaking it would be possible to resolve this, however. I used QuickTime Player v10.2 and iMovie ’11 (v9.0.8).
Capturing screen activity is fairly easy using QuickTime Player. Select New Screen Recording from under the File menu. A console appears on the screen and from here you can choose from a number of settings that will affect your recording. Make sure that you have audio recording selected as enabled. You can also include an option here to have your mouse-clicks represented visually in the final recording. Just before QuickTime starts recording, you can select to record a portion of the screen or the entire screen. When you are finished, click File-Export to save your recording to a MOV file.
Once you have your screen recording in the bag, you’ll then need to edit it. I found when I was doing this that there were a number of sections where I wanted the audio to continue but for the video to be frozen. I needed to freeze the video because I occasionally switched away from the app that I wanted to record to another app but I didn’t want this to appear in the final recording. Here’s how you do this in iMovie.
Create a new iMovie project and click on File-Import to import your MOV screen recording. The importing of this file can take a bit of time but eventually your clip will be added to your Event Library. You’ll notice that it will be divided up into little clips. Hit Cmd-A to select all the clips and drag them on to your project.
Now go to the clip in which you want to start removing video but keep the audio running. You can scrub across the clips to find this. Now Cmd-click on the point in time when you want to start removing the video. Select Add Freeze Frame from the popup menu. This will add a 4 sec long video clip of the chosen frame.
Now find the point in time where you want to return to the video. Cmd-click on this point and select Split Clip. There seems to be a bug in iMovie, which means that freeze frames cannot last for fractions of a second and so you will have to make sure that the removed video does not contain fractions of a second. So you may have to hit Cmd-Z to undo a few times until you have created a video clip that is exactly 5, 6, 7 or however many seconds are required to remove the offending video section.
Once you get this right, hover over the freeze frame clip and click the Settings icon. Select Clip Adjustments and in the Clip tab enter the duration in seconds of the video clip that is to be removed. Click Done to confirm. Now Cmd-click on your video clip to be removed and select Detach Audio. This will create an audio clip representation below the video clip. Drag this over to the left until it begins at the start of the freeze frame clip. Now Cmd-click on the video clip that you want to remove and choose Delete Selection.
If you play the project from just before the edit you will find that your audio plays through without interruption, while the video is frozen for a certain amount of time before continuing.