hiding faces masks

7/31/2019 Hiding Faces Masks

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Hiding faces on videos:Masks

This is a mini How-To to make videos during demostrations while preservingpeople's anonymousness.

This kind of documentation comes from the experience of indymedia's videosabused by police and repressive institutions in several countries around theworld...


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The next software we'll propose will be known for osx users, imovie.This is a non free licensed software so you'll need ffpmeg2theora libraries to

encode your video in a free format.

Imovie has a basilar interface but it's able to andle also some compositingeffect just as masks.

In this case we can define a mask as a black and white image (or clip)whose value at each pixel determines it's opacity (or alpha) value.

So a white pixel would indicate an opaque pixel, black a transparent one,and grey values varying degrees of transparency.You may recognize that a mask acts like a stencil.

In compositing, two images (or clips) are combined in one of several waysusing a mask. The most common way is to place one image (the

foreground) over another (the background). Where the mask is darker,

indicating transparency, the background image will show through theforeground. Where the mask is brighter, indicating opacity, the foreground

image will block the background.With Imove you are not able to move the mask in anycase.

IMOVIE

1_Import your video in imovie and then put it TWO TIMES in the timeline.

The result will be two clips in timeline, now drag a blur effect to the secondone.

The result will be the same as the image below.


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2_Create (with Gimp, for example) or find an image or clip to use as a mask.Ideally, the mask should be black and white.Now import the mask on imovie.

3_Place the mask in the timeline,between the two clips.


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4_Now if the mask is a clip; trim the mask so that it is the exact sameduration as the first clip in the timeline. If it is a still image, set its duration tomatch the first clip.

((!!)) IItt iiss eesssseennttiiaall tthhaatt tthhee ffiirrsstt cclliipp aannddtthhee mmaasskk bbee tthhee eexxaacctt ssaammee lleennggtthh..

5_Select the first clip in timeline..

6_Choose ss| Composite in the Effects panel.


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7_Click the apply botton.

8_Wait for the clip to render.

Try playing with the Mode slider of the effect, and notice the various ways inwhich the mask can combine the two clips. The first clip is clip A, the secondclip is clip B.The most common modes are A over B and B over A.The other modes are used for more specialized effects.

This is what we obtain.


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FINAL CUT PROLets investigate how to hide child's face in this video with final cut pro.

First of all we have 3 video track on timeline and our child's video clip will be

repeated two times on track1 and on track3;this two video tracks must besyncronized and the second track is empty by now.

Now we're going to make unrecognizable V3 video (the one on top).Choose on browser the "gaussian blur" effect (blur directory) and drop it tothe clip on V3; now double click on the clip on timeline and open tab "filters"on Viewer, from there you can configure the slider "Radius" to obtain thedesired blur.


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In the Canvas window you can see that the effect has affected the wholevideo; this is because the v1 video clip covers (by now) the one without bluron V3.In the media generator menu below the viewer on the right choose "shapes-> oval" to obtain a white oval on black background.

If your mask must have different shape than use Gimp to make a black/whiteimage of the shape you prefer.THis mask is able to make the original clip appear on the background(instead of dark) and the "blured" clip in the oval (instead of white).Because we've synchronized the clips, we'll obtain the effect of one clip withone oval shape blured that we can move as we want.Now put che "oval shape" clip on V2 and trim it to make it long as the others.


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PREMIEREHere we'll create for you a mosaic mask to oscure the face of a guy walking.

Here is where we start.

1_Make a copy of the clip and put it in Video2 with "edit-> copy" and "edit->paste"

MMaakkee ssuurree iitt iiss aann eexxaacctt ccooppyy..

2_Then apply a filter to the Video2 clip dropping it from the video filtersdirectory called stylize to the clip in timeline.


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We can configure the effect in the effect controls window.Now the mosainc pattern is applied to the entire clip.

3_Then we open the Title designer to create the mask; this is in order toapply the effect only to the guy's face.Keeping selection on Video2 and clicking "file-> new-> title" a new windowwill appear; here we select the ellipse tool.

4_We'll resize the ellipse and place itas we prefer.


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5_Now we want hte mask to act as a "matte" so we have to configure in theschedule on the right the value "color" to the mask, white.

6_After saving mask as "mosaic_mask" we drop it on Video3 and resize it.

7_Now we select Video2 and going to the effect controls window we click on"trasparency setup" and select "key type matte" on color white to tellpremiere to use the mask in order to limit the mosaic effect on video2 clip.


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8_Finally we what to create the animation to keep the circle on guy's face:we'll use the filter called "transform" on filters folder "video-> distort".We drop the filter to video3.

9_Now the animation is a matter of keyframes.To have a keyframe trackwe just have to click first on the triangle near thetitle "video3" in the timeline than in the shape on the left of the red square; forthe rest of the time just click between the two black arrows and you'll have akeyframe in the frame that's in front of you in the monitor.

Use the two arrows to movebetween keyframes.


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10_Now we just have to move the circle on the monitor window, setting itproperly to each keyframe point, the animation will be done by Premiere.So when the guy moves out of the circle, set the keyframe and then changethe position of the mask.

WELL DONE!

Now you can publish if you're still alive ;)

hiding faces masks

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