Removing a Moving Object with BCC 5 AE's Motion Key Filter

Ever needed to fix a clip where an unwanted or unexpected object appears in the scene? A car is suddenly passing across or a stage hand got in the shot by accident? And re-shooting is expensive or impossible? You would be facing hours of tedious frame-by-frame rotoscoping to get rid of the pesky element in your video...

But not with Boris RED or Boris Continuum Complete! As long as the object is moving in relation to the scene, this job can be done in minutes instead of days using the specialized Boris Motion Key filter. The filter is based on Optical Flow technology that uses intra-frame data to cleanly remove any moving object.

In this tutorial, we will use Boris Continuum Complete 5 AE's Motion Key filter to successfully remove a moving foreground object from a clip in Adobe Premiere Pro CS3.

In this example, the object you remove is a silver car...

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The original image is on the left. The final image is on the right.

Download the media and project file for this tutorial
(Clips provided courtesy of Artbeats, www.artbeats.com)


1. Create a new project and import the "remove_auto_before.mov" (Arbeats) file. Then, drag the file from the Project window into the Video 1 track in your new sequence.

2. Apply the BCC Motion Key Effect by opening the Video Effects Folder in the Effects tab and dragging the Motion Key Effect from the BCC5 Keys and Matte folder onto the clip.

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3. Play the clip. It is a locked down shot with a silver car passing through an intersection. You will remove the silver car from this clip.

4. In the Effect Controls tab you can see the parameters you will need to adjust to remove the car. The Mode menu defaults to Setup Region, in which a line is drawn around the area that will be removed. Since the object we're removing is moving, you need to keyframe the region.

5. The Area Selection menu allows you to choose a starting shape in which to draw your mask. To remove the car we'll choose rectangle.

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6. Add a keyframe to the first frame in the clip by hitting the "toggle animation" button for the following controls:

  • Area Position/Offset sets the X and Y position of the Setup Region.
  • Area Scale sets the size of the Setup Region.
  • Area Aspect sets the aspect ratio of the Setup Region.

Adjust the controls to position the rectangle at the start of the clip so that it encompasses the car.

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7. Move a few frames forward, add new keyframes, and reposition the rectangle so that it surrounds the car. Repeat this step until you have completed the entire clip. You can scrub through or play the clip to make sure the mask encompasses the car for the whole duration.

8. Set the Mode menu to Show Mask. The colors displayed in the mask region indicate the filter's confidence of removing the object. A clear area means that the filter cannot remove the object. Red areas will be successfully removed. Blue areas indicate a good chance of removing most pixels.

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9. Increase the Replacement Range if there are any areas of the mask that are clear. Replacement Range limits the frames that can be used as source material relative to the current frame. This can provide a better result depending on the speed of the moving object and the number of frames in the clip.

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10. To view the final result, set the Mode menu to Remove Area.

11. Hit play to preview. When the filter finishes processing the image, check to ensure that the foreground object has been removed to your satisfaction. Hit Enter to render the effect.

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Watch the final rendered movie »

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