Software for side by side video

I find your request a bit confusing?. How are you planing to capture the footage?. The way i read it is that :A: software is going to do that.
What editing software do you have?

 

If you want to have two simultaneous views of the same live process, you need to have two cameras capturing the two views of the action. You'll need to use a clapboard or a hand clap or time code to synchronize the two streams.

Once you import them both into a NLE (non-linear editor) like FCPX, you would then be able to display the two streams simultaneously.

I hope this helps.

 

You need editing software or compositing software....

If you dont want to buy anything try downloading the trial of FCPX or the trail for After Effects....either one of those will easily allow you to do what you want