That is called a Vignette effect and its rather easy to do in Sony Vegas, I have never used Pinnacle before but I will tell you how to in Sony Vegas until someone else can help out with it in Pinnacle as it may be similar steps.
Go to Effects and then drag the Cookie Cutter effect onto the track. Once placed adjust its size a bit until it looks right playing around with the shape choices as theres circles and oval etc and then adjust the feather to soften its edges and so it looks they way you would like it. There are other methods but I think this is the fastest to achieve the result,