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Highlighting a Moving Object

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Highlighting a Moving Object

Postby Bill Hunt » Thu Apr 09, 2009 7:27 pm

I posted this article into the Premiere Elements forum, but the links are all lost, and Search cannot locate the original post. Even Google lists the old links, which are all dead. I hope that there is not a problem posting it here, as there have been several recent threads to which it can apply.

Highlighting a Moving Object in Premiere Elements with a Track Matte

This is a step-by-step article on “highlighting” a moving object in Premiere Elements (PE). There are variations of this used to obscure the identity of a person, license plate or even add “softening” to skin on a model. They all work alike, though the Effect chosen will obviously be different. For this example, I will be using PE4 and creating a “highlight” with the Track Matte Effect.

In our case, we’ll “highlight” a football player in some game footage. Since I’m dealing with words, and not doing a visual and audible tutorial here, you will need to tune up your imagination, if you are going to play along at home.

Imagine that we have a 30 sec. Clip of our player, Tom, a wide-receiver in an American football game. We have placed the Clip on the Timeline in PE, and it’s on Video Track 1. Our Clip has a static camera, with just a wide enough lens angle to include the line of scrimmage and the goal line. The Clip starts with his team lined up at the line of scrimmage. He’s stationary on the end of the formation, closest to our camera. When the ball is snapped, he’ll run left to right and “slant” toward the middle of the field. At that point, the quarterback will throw to him. He’ll catch the ball and continue down the field, crossing the goal line for a touchdown. During this play, there will a lot of other players around him and we want to make sure that he stands out in the Video Clip for the entire play. Since he’s starting with the 21 other players around him and he’s static, you have his exact location and it’s fixed for say 2 sec. Let’s play ball.

Now that you have the mental image in mind, you have some decisions to make. The first is how do we make Tom stand out from the other players and the rest of the field of view. We could “brighten him up,” but then the exposure of his image would suffer. Let’s assume that the exposure is perfect now for the entire field of view. Instead of brightening him, let’s darken the rest of the field of view. We’ll create what will appear to be a moving “spotlight” on him, but in reality we will be creating a moving “shadow” on the rest of the field. It’s really like taking a piece of cardboard with a hole in it, and moving it between a light source and the ground. The cardboard throws a “shadow,” but the hole lets the full illumination through. We are going to create that piece of cardboard, in the Titler in PE and “punch a hole” in it, but first we need to “duplicate” our 30 sec. Clip on Video Track 1. We’ll Alt-click on it, to select just the Video portion, as we do not need to duplicate the Audio, then hit Ctrl-c to Copy it to the Clipboard. Because PE will not allow us to select the Track to Paste to, we need to position the CTI (Current Time Indicator) to the end of our Clip, where there is nothing else. The easiest way to do this is to hit “End,” to go to the end of our Timeline. Now, we Ctrl-v to Paste the copy of the Clip onto the Timeline. Next we’ll move this copy to Video Track 2 and align it perfectly with the original Clip on Video Track 1. The Snap feature allows us to align the CTI to the head of our original Clip then drag our duplicate to that point, but onto Video Track 2. Check that the two Clips are aligned and that you did not exceed the Snap function.

We are set to create our “highlight” with the Titler. In the toolbar, click Title>New From Default Still. This creates a new Title with a default Text Box. We don’t want “text,” so we’ll click on the Selection Tool (the little “arrow” at the top of the Titler’s Toolbox. When we see the bounding box around our Text Box, we hit Delete to remove it. Now, go back to the Toolbox and select the Ellipse Tool. Click in our Title and Shift-drag to create a circle. If everything is set at default, tt will appear white over a black field. Size it roughly to about the size of Tom. We can fine-tune its size later.

Place this new Title on Video Track 3 at the start of our original Clip (Video Track 1) and our aligned duplicate Clip (Video Track 2). Notice that it’s only about 5 sec. long (the normal default), so we want to click on the tail of the Title Clip and drag it to the full length (30 sec.) of our other two Clips. If we play our Timeline now, we’ll have a white circle over an area of the two Clips below. Also, we’ll only see the white circle and the duplicate Clip, since they are “above” our original Clip and will obscure it.

Now is a good time to adjust the size and starting location of our circle. Dbl-click the Title to open the Titler. Use the Selection Tool to get the bounding box around our circle and Shift-click-drag on one corner to change the size. We hold Shift, so that our circle stays, well circular and does not turn into an ellipse. Once we have the size about right (remember we can always come back an increase/decrease the size), drag it around, until it’s over Tom at the head of the Clip on Video Track 2. For this, we want the CTI to be over the first frame of our Clip. We’ll hit the Home key, as this is the only Clip on our imaginary Timeline. If you already have others, then you’ll want to use PageUp, or PageDown to move the CTI to our first frame of this particular Clip.

Our white circle is now sized and positioned over Tom. We like the exposure of Tom, and we want to darken everything around him, so that he stands out from the other players and the field. That is why we duplicated our Clip. We’re going to add a couple of Effects to the duplicate, but not to the original. I’m going to choose Brightness & Contrast, so that I can adjust the duplicate Clip’s apparent exposure down. Once applied to our duplicate Clip, we need to adjust the Properties of this Effect. With our duplicate Clip selected, we can go to the Properties Panel and hit the Edit Effects button. There you’ll see Motion, Opacity and also our Brightness & Contrast Effect. The first two are always present by default for any Clip. If the properties for the Brightness & Contrast Effect are not visible, then click the little right-pointing arrowhead between the “eyeball” and the Effect’s name. Now, you can see two sliders, one for Brightness and the other for Contrast. You can drag the sliders to preview the change, or you can click on the setting (to the right side of each slider’s path) to type in an amount. I chose -40.0 for Brightness and -25.0 for Contrast. This gives us a darker and flatter image in our duplicate Clip.

Now we have the look that we want for our background, but Tom is also dark and flat. Not what we want. We want Tom’s image to come from the original Clip on Video Track 1, and the image of everything else to come from the adjusted duplicate Clip on Video Track 2. That is where the Track Matte Key Effect will be used. We will drag the Track Matte Key Effect to our duplicate Clip on Video Track 2. With this duplicate Clip selected if we look in the Properties Panel, we’ll now see that the Track Matte Key Effect has been added. Click on it and hit the Edit Effect button again. This will give us control of how this Effect works. It has three settings: Matte with a drop down, Composite Using with a drop-down and Reverse with a check box. For Matte, we’ll chose Video 3 (our Title) from the drop-down. For Composite Using let’s choose Matte Alpha from the drop-down. Now, we can see in the Monitor Panel that this is not what we want. Because we have a white circle in our Title on Video Track 3, the background image is from the Clip on Video Track 1 and is properly exposed, while Tom is coming from the darkened and flattened Clip on Video Track 2. This is where the third setting in the Track Matte Key Effect, Reverse comes in. Now, click the checkbox. Tom’s image should be coming from the original Clip on Video Track 1 and the background from the duplicate Clip on Video Track 2.

Play the Clips and watch how Tom’s image is correctly exposed, while everything else is darker and flatter. Things are looking good, but with one exception. Our Title, which creates the Track Matte Key Effect is staying still, while Tom is running down the field, crossing towards the middle, catching the pass and running for a touchdown. As soon as the play starts, he runs out of the circle and into the darkened flatter portion of the image. We need to get our circle to “follow” Tom. That’s where Motion Keyframing comes in.

Hit Home to move the CTI to the first frame of all of our Clips. Select our Title (which is being used in the Track Matte Key Effect for the duplicate Clip on Video Track 2) and click on the Edit Effects button. We are now going to add Keyframes via the Motion Effects. Since we have positioned our circle over Tom, while he’s in formation and static in the first frame of our Clips, we can set a Position Keyframe there (on the first frame). We will ignore the other settings under Motion for now. To do this, we click on the “stopwatch” icon and can see a little “diamond” added to orange line in our Title/Track Matte at the first frame. Here, the position is fine. slowly scrub the Timeline to the point that the ball is snapped, and Tom first starts to move. At this point, we want to add another Keyframe to anchor the Position at this point. We click on the little “diamond” below the title Video 3 (far left side of the Timeline) and a second Keyframe is added. It appears on the orange line in our Title/Track Matte Clip also.

Now, things involve a little labor. For starters, we’ll scrub our Timeline along until Tom slants to the middle of the field. At this point we’ll place a third Motion Keyframe. With the CTI over this Motion Keyframe, we need to move our Title/Track Matte so that it is over Tom at this point. We can do this by either dragging in the Monitor (notice that it has a set of “cross-hairs,” since we are in the Edit Effects mode, or by dragging on the value for horizontal Position, or typing in a value after clicking ON the horizontal value. We may have to go into the area between our Keyframe #2 and #3, and add additional Keyframes, adjusting our Position, depending on how linear Tom’s path is, and if he runs at a constant speed, across the field of view. for now, we have just the three Keyframes. PE will fill in the other frames, between these two Keyframes.

At the point of Motion Keyframe #3, Tom slants towards the middle of the field. We’ll use Keyframe #3 as the “anchor” for our next change. Scrub the CTI to the point in the Clip that Tom changes his direction again, just before he catches the pass. In our imaginary football game, we’ll say that the pass is caught, just after he breaks off his slant and heads toward the goal line. At the point that he changes direction, we add another Motion Keyframe, and then move our Title/Track Matte to this point with the use of both the vertical and horizontal positioning.

Decision time - Tom has run towards the center of the field, so his image has gotten smaller. We might want to make our circle smaller too. If so, using the position of the two Motion Keyframes that define his slant pattern, we can add Scale Keyframes at those two points. The first is to anchor the Scale, and the second to set where the Scale ends up. At the second of these two Scale Keyframes, we adjust the Scale to something smaller. Use your eyes for this.

Now Tom is running straight for the goal line, but has not caught the ball. Depending on whether he breaks his stride, we may only need to add one more Motion Keyframe. If he pauses, then we’ll add however many are necessary. Let’s say that he never breaks stride, catches the ball on the full run and heads straight towards the end zone. We’ll scrub to the frame where he crosses the goal line and kneels down clutching the ball and raising it above his head. Here, we’ll add the last Motion Keyframe and adjust our Title/Track Matte to that location. Again, depending on how linear Tom’s speed is, we may have to tweak our Track Matte’s Motion with additional Motion Keyframes.

Now, in our example, we created a hard-edged circle to “highlight” Tom. If we wanted it to be soft-edged, we could add a little Gaussian Blur Effect to the Title/Track Matte. We could even Keyframe it’s value, so that when Tom kneels in the end zone, it sharpens (by decreasing the value of the Gaussian Blur to 0).

Also, instead of adding the Brightness & Contrast to our dupe Clip on Video Track 2, we could have added a Gaussian Blur to that Clip, so that Tom was sharp, and the background had a slight Blur Effect. We could even do a combo of Brightness & Contrast plus the Gaussian Blur to make Tom really stand out really well. The choices are endless. Hey, how about making the background bluer, or greener, and keeping Tom just as he was filmed?

Now, if the camera has panned with Tom, we will have fewer Motion Keyframes, depending on how well the camera person followed Tom.

As I stated early on, I’d have done this in Premiere Pro.

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Re: Highlighting a Moving Object

Postby pch006 » Wed Dec 21, 2011 8:31 pm

I have done this in Premiere Elements-8 and it is just about the same process. To separate the audio from the video in PE is to highlight the clip and then Alt and left click on the clip. There are many interesting uses for track mattes and I have experimented with some of them and made a little video tutorial on one of my ideas.
[youtube]http://www.youtube.com/watch?v=WDMD4fjNf5E[/youtube]
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