Edit mocap animations?

I’m making a survival horror game, I don’t want to release too much information on the game, so I’ll keep it short and sweet.

The Raw Mocap Animation is fantastic, but I’m stuck, I want to edit the arm position to say… holding a rifle. Would I have to edit each Individual frame? Or is there an easier way? I have no idea what I’m doing as far as this goes…

MotionBuilder the software from Autodesk that is the photoshop of motion capture - you can edit away in there.

In case anyone finds this in the future, you can edit directly using Unity’s built-in animator. It isn’t the fanciest tool for animation, so it is tedious, but for small edits it is there.
Here’s a youtube video that explains how to convert the animation so that it isn’t read only and then from there you can move your skeleton and re-key the frames.