Saturday, December 20, 2014

PE: Face Blur Track Matte Keying


A frequent Premiere Elements question is "How do I blur a face in my video?" One classical way to do this is using a Track Matte Keying* approach. The following is the result when this was done using Premiere Elements 12/12.1 on Windows 7 Professional SP1 64 bit, NTSC DV Standard project, and an animated 720 x 480 @ 29.97 progressive frames per second Windows Media Video 9.wmv file with a "Robot Video Intruder".


Demo 1. Blurring Face of the Robot Video Intruder.


The details to follow are specific for producing the file shown in Demo 1, but are in principle applicable to other Premiere Elements versions to achieve the Face Blur goal.

STEP 1.**

Video Track 4.  "Matte" is created as a colored circle (white or red will work) to cover the area of the Robot's face. This "Matte" can be created in Premiere Elements Titler and was in this example. In subsequent steps, this circle's position is keyframed to move with the Robot's face which is to be hidden by a blur.

Video Track 3. Original video file with "Robot Video Intruder" traveling in the frame from off screen top right to on screen top left to on screen bottom  left to on screen bottom right.


Probably the most detailed part of this workflow is keyframing the Position property of the circle (the area that is going to define the transparency in the Robot's face which is going to be replaced by the blur). Next phase below is the keyframing of the circle's Position property.

At this point....
  • Video Track 4. Matte (Titler file with circle shape sized to cover the Robot's face)
  • Video Track 3. Original video.

In the original video, the Robot enters the frame from off screen, top right corner of the frame. So at the beginning of the Timeline, position the Video Track 4 circle off screen just outside the top right corner of the frame.
Tip: To make sure that the correct file is selected for these movements, right click the monitor, select Select, and then click on the file name for the Track Matte before moving the Matte.


  • Select/highlight the Matte on Video Track 4.
  • Go to Applied Effects Tab/Applied Effects Palette/Motion Panel expanded, and click on the Toggle Animation button. See Figure 1.
  • Go back to the Edit area monitor. Remember, with the Matte on Video Track 4 selected. Timeline Indicator is at the beginning of the Timeline content.
  •  Move the Timeline Indicator to the right in order to start the Robot's appearance in stages. Then with the mouse cursor move the circle from off screen to on screen on top of the Robot's face. See Figure 2.
  • Move the Timeline Indicator so that the Robot goes to its next position, and then move the circle so that it covers the Robot's face in the Robot's new position.
  • Continue that circle tracking of the Robot's face until the Robot reaches its final destination at the bottom right corner of the frame.

Figure 1. Initiation Of Position Keyframing With Toggle Animation.

Figure 2. Start Of Staged Matte Tracking Of Robot's Face.

STEP 3.**

Video Track 3. Original video file to which a Track Matte effect is applied via fx Effects/Keying/Track Matte, followed by edit of the Track Matte via Applied Effects/Applied Effects Palette/Track Matte Panel expanded so that the settings are:
Matte = Video 4
Composite Using: Matte Alpha

See Figure 3.

Figure 3. Track Matte Keying To Create Area Of Transparency In Robot's Face Which Will Be Subsequently Filled With Fast Blur.
STEP 4.**

Video Track 2. Original video file to which a Fast Blur has been applied by dragging the Fast Blur effect into this clip from fx Effects/Blur & Sharpen/Fast Blur. This is just a blurred version of the original video - no Track Matte Keying applied.

See Figure 4.

Figure 4. Area Of Transparency Created By Track Matte Now Replaced By Fast Blur.

* A description of the Track Matte Key can be found in the Adobe document titled Adobe Premiere Elements Help/Effects reference

** Video tracks used in this example were 2, 3, and 4. Video tracks 1, 2, and 3 could have been used.
***An alternative setup of the tracks (more frequently seen) for the Face Blur is
  • Video Track 3. Track Matte with shape's position keyframed to track the face
  • Video Track 2. Original Video, with Blur effect as well as Track Matte effect applied to the video. Typically Reverse is unchecked in the Track Matte Panel expanded setup in the Applied Effects Tab/Applied Effects Palette/Track Matte Panel expanded.
  • Video Track 1. Original Video as is.
But in this specific blog's how to example, there is an unwanted blurring in that setup when the Robot Video Intruder's path is behind the Christmas wreath. If that type of situation is not involved in your work, then try the more frequently seen route mentioned in this footnote.

Work in progress on this one. But, seems OK after several proof readings.