Heather –
If I remember correctly (and it has been a Looooong time since I’ve hauled out my Viewmaster from the closet), the view presented is of a box with smoothly curved corners (squarish, not really rectangular). Although I haven’t specifically gone for this look, I often create 4:3 boxes with curved corners either in photoshop or Illustrator. I make a black box on a white background (it’s easier to control the corners of the box in Illustrator), and then import the graphic into AE, put it at the bottom of my timeline, and use a Compound Alpha, using the luminance value of the box graphic (or inverse luminance – I can’t remember which) to cut the corners of my clip. The compound alpha is much easier than putting the box above each layer I need clipped and then using that as a mask channel (although you can do it that way). Have fun!
Joe Bourke
Art Director / WMUR-TV