Composite Assets with the Mask Effect

The Mask effect is a great way to composite clips in your video. The word composite means to merge or fuse, and in this tutorial compositing assets refers to merging elements or clips in your video. Masking allows you to create holes in one clip that allow another clip to show through. Another way to think of it is as selective transparency. In the examples below, the shape and placement of a mask on a clip determines the visibility of what is underneath.

There are many ways to use this effect. This tutorial is going to explore two.

Creating a Background and Foreground Effect

In this first example, the shape of a mask on one layer allows another layer to show through, creating an interesting background and foreground effect. Let's get started.

1. Import an image or video clip into the Camtasia media bin. For this tutorial, start with an image that focuses on a single subject like a car, insect, or flower. Once you've worked through the tutorial once, try it again with more complicated images or video clips.
2. Drag the image or video from the media bin to the timeline.


3. Adjust the canvas view to 75% to see more of the canvas area.
   
4. At this point, if your media clip doesn't fit the canvas exactly, that's okay. You can either adjust the size of your image to fit your canvas using the control handles on the preview pane, or choose Edit > Adjust Canvas, and edit the dimensions of your canvas to fit your image.
5. Create another instance by choosing Edit > Copy, then Edit > Paste. The copy should generate on a new track directly above the original.
6. Choose Edit > Deselect All so that neither instance is selected.
7. Click on the Video FX tab and select Mask.
   
8. Drag the effect to the timeline, and drop it the on the second image, the one on the upper track.
   
9. Applying the effect will automatically select that clip. On the canvas, click and drag the control points of the red rectangle, until it frames your subject.
   
10. Click the Properties button to open the properties. In the Basic Properties and Effects tab, adjust the scale of your image to 125% and press Enter or Return.
    


11. In the Annotations tab, click and drag the blur annotation to a new track between the images on the timeline. Hovering between the two tracks will auto-generate another track. Drop the blur annotation onto the new track.



12. Use the control handles to adjust the scale of the blur annotation. Size it to fit your canvas (which should still be the same size as the images), then open the properties and set the blur opacity to 75%.
    
13. Save your work by choosing File > Save.
    

Creating an Inverted Mask Effect

This second example demonstrates how to use inverted shapes as a mask to hide part of your clip.

1. Import an image or video clip and drag it onto the timeline.
   
2. Adjust the canvas view to 75% to see more of the canvas area.
   
3. In the Annotations tab, click on shapes and select the black rectangle.
4. Drag the rectangle shape to the timeline and drop it on the track directly above your media clip.
   
5. Change the duration of the rectangle on the timeline to match that of your media clip.
   
6. Size the shape to fit your canvas by using the control handles or the scale slider control in the properties.
   
7. Click on the Video FX tab and select Mask.
8. Drag the effect to the timeline, and drop it on the shape you created. Notice that it changes the shape of your rectangle to an oval. For now, leave it as an oval. If you wish to change it back to a rectangle, though, you can do so in the Basic Properties and Effects tab, under Mask. Simply change the dropdown option from oval to rectangle.
   
9. Click on the Properties button to open the properties, and in the Basic Properties and Effects tab, under Mask, check Invert.
   
10. Set the Mask Blend to 0. Set the Mask Opacity to 30%.
11. On the canvas, click and drag the red control handles, until they frame your subject.


12. Save your work by choosing File > Save.
    

There are many other ways to use masks to create layered effects in Camtasia for Mac. Neither of these examples work extensively with video clips, but if you use the Custom animation to change the effects properties over time, you can create some really neat mask effects.