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Using the BCC Matchmove Filter in After Effects

Media Used in this Exercise:

We're going to use the BCC Match Move filter to match the crane-up camera movement of one clip to that of a clip which was shot with a locked down camera and generate a seamless composite of the two clips making them appear as though they were shot with the same camera - all right within the Match Move filter. We'll start the project by importing the two clips that we need into a new project within After Effects. let's take a look at the two clips that we are using - one is a crane shot of a street scene taken on Fisherman's Wharf in San Francisco while the other is an underwater scene of a fish swimming near some coral along the California coast. In the crane scene, there is a clock on a post and we are going to comp the fish scene into the clock face. The fish clip has a circular alpha cut-out shape so that only the pixels within the circle are opaque.

After Effects filters

To start, we create a new comp of 5 seconds duration and drag the fish clip into the comp. Drag the street scene with the clock into the timeline below the fish clip. Let's preview to RAM and study the clip for a moment so that we can successfully apply the filter and comp in the fish. Upon review of the clip, we can see that the letters at the bottom of the clock appear to remain on screen for the duration of the effect, which will provide us with a good source for motion tracking without having to add keyframes.

After Effects plugin

Stop the clip playback, select the background clip (the clock) and apply the filter by selecting it from the pull down menu - Effect>BCC 5 Distortion and Perspective>Match Move.

motion graphics

Now let's track the background clip. Move the CTI to the start o the clip, and twirl down the motion tracker group in the BCC Match Move filter controls. By default the filter will set itself to track the clip to which it was applied and in this case that it what we want to do, however it is possible to track and recover the motion from one clip, then apply that tracking data to composite two entirely different clips together.

video effect

To set-up the tracker, enable the track-on-the-fly feature. Next we need to set the search and target regions in the tracker. Drag the tracker center to the bottom of the letter F on the sign. Then expand the target area (the inner box) to 15 pixels and leave the search at it's default value of 40. Now that the search and target regions have been set, we are ready to track. Just click on the play button in the AE time controls and the filter will analyze / track the feature. Tracking is complete when the clip has played through every frame in the comp. There are indicators at the bottom of the composite window that provide information regarding the integrity of the tracking process - a solid green bar indicates that all frames were tracked, while the color purple is used to indicate a non-tracked frame. A red bar is displayed to indicate the current time. When tracking has completed, you may want to monitor the tracker running through the frames to make sure that the tracker did not drift or move off target. Once satisfied with the tracking data, you can disable the track-on-the-fly feature.

3rd party AE

So ... now that we have recovered the camera motion, we need to instruct the filter to use this motion to control the movement of the foreground clip in the composite, which in this case is the fish clip. Twirl down the Match Move parameter group and set the MM foreground to the shot of the fish, which we have already masked and precomped. The fish will move correctly now to match the camera movement from the background clip, but it is not in the correct position over the clock face.

Adobe video

We'll reposition the fish so that it is more closely aligned with the clock in the background. By using the offset parameters from the motion tracker group, we can change the relative position offset of the foreground clip to the recovered tracker data. Remember that we tracked the letter at the bottom of the clock and now the center of the fish precomp is locked to the letters so we just want to offset the tracker data as a group. We'll set the offset x to 0.050 and the offset y value to -0.330. This places the precomp directly over the clock. But there is perspective distortion in the background shot that we need to apply to the foreground to make a convincing composite. To fix this, we let the filter do the work by using the built-in DVE controls to match the perspective in the background shot.

target moving video

Let's twirl down the Transform control group. This is where we apply transform operations to the foreground clip. First unlock the scale and set the scale x to 81 percent and the scale y to 98 percent. Observe now that we're getting close to a match. Fine tune the scale parameters so that the clip fits the perspective scale of the clock face. Set the Tumble parameter to - 14 degrees and set the Spin parameter to + 25 degrees. Bingo - the foreground clip now sits right on top of the background clip with matching perspective distortion. Now we'll just go in and blend the edges of the foreground clip so that it looks like the two clips are one shot. The controls for this function are located in the Composite group.

target moving video

Twirl down the Composite group and then twirl down the Light Wrap group, set the Wrap Lightness value to 50 and set the Wrap Width parameter to a value of 3. We can leave the wrap softness at it's default setting of 10. We'll change the wrap mode from Normal to Add. The edge of the foreground object have now been set to grip the edge of the clock in the background object. To complete the composite we will make a change to the apply mode that the filter is using. We'll set the Apply Mode for the filter to Scale Multiply and we're finished. Let's now preview to RAM to view the final result.

BCC matchmove