I’ve seen the question of how to blur out faces to obscure identity in VT Edit come up a few times in Newtek’s VT Forums.  A face might need to be blurred to protect a person’s identity, or if they haven’t given permission to be recorded, or a license plate might need to be blurred to protect privacy.  Usually when the question comes up the standard answer is to use Aura, with a link to this tutorial: http://www.newtek.com/products/vt/aura/tutorials/lesson09/lesson09.html

If you haven’t looked at that tutorial do, it’s about using pixel tracker to have Aura track an object as it moves through a shot, and apply an image on that spot.  It is very powerful, especially if the subject is moving a lot in frame. Pixel tracker follows it automatically. Aura is a very powerful tool, and there are many situations where it can be used in this manner, but for a simple identity hiding blur, the job can be done much faster right inside VT Edit. You can get the job done in the editor in not much more time than it takes just to load a 30 second clip into Aura, let alone create the effect and render it out.

In a nutshell what we are going to do is make a copy of our video clip, lay it on top of the original video, then blur the copy, and crop it down to cover only the area we want to be blurred so that the clear video from the background clip shows up everywhere else. 

Make sense?  Lets go through the steps. 

To start with we need a clip of someone who needs to be hidden.  I grabbed this shot of me at my desk, largely because it was handy, and I had just been using it when this subject came up.  You probably won’t have a video clip of me, but that’s OK, use what you’ve got.

First we lay the video clip in the timeline or control track, by dragging it over from the filebin.  Then we copy the video portion of the clip by clicking on it and copying it with <ctrl>C.  Then, we paste it with <ctrl>V.  That will probably also copy the audio track.  If it does, just click on the second audio track and delete it with the delete key, no biggie.

You can see the second clip, lined up with the first and highlighted.  The second clip should be below the first, if not drag it there, and make sure it is highlighted.

Now, for the blur.  By clicking on the Control Tree tab in the upper half of the VT Edit window, we can switch its view from the storyboard to the control tree of whatever clip we have highlighted.  In this case it’s the lowest, or foreground image of me.  To see what’s going on lets make sure the cursor in the timeline is somewhere in the middle of the clips, that way they show up on the Program Out in the VT-Vision window, or your Program Out monitor if you have one setup (you really should, if you don’t.)

As you can see, the control tree view has lots items we can adjust about the video.  To start with, we’re going to blur it, to the point of unrecognizability.

By clicking the + sign next to Blur, the Blur items expand to show us that we have the option to blur on the X (horizontal) axis and the Y (vertical) axis.  All we have to do is either input values for X and Y, or use the knobs to turn them up to the point that my face is an unrecognizable blur.

Cranking the X and Y blurs up to around 10 seems to do the trick quite nicely.  That looks like how I feel sometimes first thing in the morning.

But we don’t want to blur the whole video, so we’re going to crop the blurred clip down, so that we can see the clear video behind it.  To start with, we need to make sure that overlay is turned on for our blurred clip.  With our clip selected, it is a checkbox item on the bottom of the VT Edit window.  If we don’t have overlay on, our blurred image will just be surrounded by black when we crop it.

Before we go further, let’s make sure our cursor in the timeline is at the start of the clip.  Now, back to the control tree.  Lets give the + next to Cropping a click to open up the cropping menu.  We can crop by size, or what we want – by each of the four edges of our clip.  To see what we are doing, lets click the Positioning Tab in the bottom of our Control Tree view.  Now grab the dot next to the value for “Crop Left” and slide the mouse left or right.  In real time you will see the left edge of the blurred clip move.  In the positioner view we will see just the clip we are working on, but on the Program out we will see the edge of the blurry clip moving, revealing the unblurry clip behind it.

Now all we need to do is adjust all four of the four crop values, until we’ve blurred out just what we want to hide.

And there we have it.  The identity blur takes only 6 steps to setup (copy the clip, set it to overlay, and set our four crop values) and it all happens in realtime, so there’s no need to render something out and take it into another package like Aura for this simple effect.

But we don’t need to stop there.  Our blur has some hard edges to it, if we want to make it a little more subtle, we can fade its edges.  This is easily done by opening the Edges menu in the Control Tree, and turning up the Smooth value.

But what if our subject is moving through the scene, not just someone sitting in a chair?  Well, we don’t have pixel tracking in VTEdit, but we can set keyframe values for each of our four crop edges, and VTEdit will automatically slide the edges around smoothly between the points that we set.  As an example, lets make the left hand edge of the blur start at my face, but then extend so that by the end of the clip it blurs out the computer monitor as well.

All we have to do is go back to our Cropping options in Control Tree, and with the cursor at the beginning of the clip (either in the timeline view, or in the timeline at the top of our Positioner view) click on the button to the right of our Crop Left value.  This marks it as a keyframe.  Now, lets slide the cursor to the right side of the timeline in the Positioner view until we get to (but not past) the end of our clip.  Notice our white dot has disappeared.  That is because we are no longer in the frame that was a keyframe.  Lets turn that white dot on again, and now move the crop left value to extend our blur out to the monitor.

Now, slide the cursor over the timeline in the positioner window and watch what happens – our left edge moves as time goes by.  And once again, we get to look at and tweak this in realtime without having to wait for a render, and undo or redo to make adjustments.

Using the same method, we can move all four edges of the crop to follow a face through a shot, and we can make keyframes anywhere we need, not just at the beginning or end.  We just make a keyframe at any point our subject changes direction of movement.

What if we need to blur two subjects in the scene?  Easy, we just make another copy of our clear background layer, blur it in control tree, and crop it as needed.  Set as an overlay, our two blurred layers will be on top of the clear background layer.

Now that we’ve done the blur, we’re probably going to use it in a project and that may mean using DVEs or fades to our hidden identity shot from another shot.  But how can we do that?  If we transition to the clear background layer, our blurred face will be right on top, and we can’t DVE to the blurred layer, because it’s an overlay layer.  The answer is simple, and it lies in sub-projects.

All we have to do is shift-click on our background unblurry clip, the blurry foreground clip, and the sound clip, so that they are all highlighted, and then click the SubProject button at the top left of the VT Edit window.  Viola, we can now treat our effects composite as if it was a standalone clip, and edit it in our program.  If we want to go back and change the positioning, it’s just a matter of drilling into the subproject in timeline, or expanding it in the storyboard.