This week’s video is a bit inside-baseball to the extent that one of my colleagues was interested in learning how to blur moving objects in a movie he was making for this series. Regrettably, it’s nearly impossible in iMovie and quite difficult in my usual screencast tool, Screenflow. Fortunately, it’s easily done in Apple’s $50 Motion 5. Here’s how it’s done.
I’ve opened Motion and I’ll drag in a clip. When I play the clip you see that the personal information about this completely fictitious person can be seen. Plus, the contact card moves. So, I want to both blur this information as well as make sure that the blur moves along with it.
To do that I’ll first select my layer in Motion and duplicate it by pressing Command-D. I’ll then name the duplicate something like My Mask. I’ll then click on the Mask Tool menu, choose Rectangular mask, and then draw the rectangle around the text I want to blur.
Click Library, choose Filters, choose Blur, and then select Gaussian Blur. I’ll then drag it on top of my mask layer. This doesn’t seem to do anything, but it will. I’ll expose the Heads Up Display by clicking this button (or pressing F7) and then drag the Amount slider to the right. As I do, the rectangle mask blurs.
Adjust the beginning of the Gaussian Blur track so that blurring begins where you want it to. (If you don’t, everything under the rectangle will be blurred.)
So, now that we have our blur, let’s do something about moving it to accompany the motion of the contact card within the clip. To do that, first click on the Record button and drag the playhead to where the window starts moving.
Select the Rectangle Mask track near the bottom of then window and then use the right-arrow key to start moving through your video, frame by frame. As the information is exposed, drag the rectangle blur to cover it. This creates keyframes that direct the rectangle to move. Continue until such point that the rectangle no longer needs to move.
And that's it. Just export your project and the blur will be added to it.