There are a number of ways.
The easiest is probably just to create a title. Put a black rectangle covering the entire title, then a big white circle in the middle. Hold the shift key while drawing the circle to keep it round.
Put it on the track above your video.
Put the Track Matte Key effect on the video and in the Effect Controls panel, tell it that the matte is on the track above the video. (Usually the video is on track one and the matte is on track two in simple sequences). Use the Luma setting.
There are other ways that involve alpha instead of luma. But you will probably be happy with this.
Apply Circle effect onto your footage. Set Blending Mode to Stencil Alpha. Play with the Radius.
Hope, that's what you want.
Wow! I forgot all about the circle effect. Good catch. Much easier to deal with.
Just for your own reference...you can eliminate the black rectangle step in your suggestion and just make the white circle as a Track Matte.
I still can’t figure out how to place a video inside the white circle. I am new to Premiere Pro CS6. Never used Pro before.
I suppose. But to me, having the black readily indicates what it is in the Project panel. I think in terms of black and white, so, I include the black. But I think I like the circle effect better if all I need is a circle. Perhaps I will take a few minutes after dinner to do a quick tutorial for Fuzzy.I had to look it up. It was there in CS3, I just forgot.
Edit: OK, here is a quick tutorial. Dinner will be on the table in a minute, so I didn't clean this up. Yes, I could have dropped the effect on the clip, but I felt like double-clicking. I have no idea why. I just did.
A step by step for a Basic Track Matte
Create a Circle in Premiere Titler. Make it SOLID and FILL with White.
Place the Title ( circle) on a Video track over the Video you wish to place inside the circle.
Apply a Track Matte Effect to the Video ( not the Title)
In the FX window ( Tarck Matte) Select the Video Track that has the Title on it.
Weird Adobe User Forum has gone Non Linear!
Stevens post #6 at 2.34pm precedes my post #7 at 2.04 pm!
...and I have a time zone advantage of about 12 hrs as well.
Feature Request / Bug Report : Adobe Forum is out of synch with the the time continuum.
I would answer in a more entertaining way, but we could get moved to the lounge. Instead I will just say that is what happens when you edit a page after helping prepare dinner, but before it is all out of the oven. I never refreshed the page to see your post or I would not have edited mine, I would have responded to yours.
Or, I could tell the truth about the time machine I found stuck in a closet in the lounge, but I really shouldn't.