track & blur a face for part of a shot

[Ole Kristiansen]

Try youtube – davinci resolve track and blur a face !

[Marc Wielage]

[Thomas Kaufman] “I tried to place key frames where I want the blur to begin and end along the timeline but I must be missing something”
You could use a power window to constrain the blur, then use Opacity to allow the blur or remove it as you see fit. But you do have to keyframe it. It’s basically dissolving the effect in when you need it, then dissolving it out when you don’t need it.

[Thomas Kaufman]

Thanks, Marc, very helpful!

Thomas Kaufman, DP
Washington, DC

[Eric Santiago]

[Marc Wielage] “then use Opacity to allow the blur or remove it as you see fit.”

Most of the time I just do a next frame transform.
Similar to “now you see it, now you dont”.
The opacity keyframe works the same but most of the time I am having to key the position anyway.
This is during those tricky tracking settings.
Too bad Resolve didnt have a Adjustment Layer type of option or simple on/off keyframe toggle.

[Marc Wielage]

[Eric Santiago] “The opacity keyframe works the same but most of the time I am having to key the position anyway.”
It takes less time to do it than explain it.

Another method (if you’re keying the entire frame and not just a window) is to use the Key Output control. There are advantages and disadvantages of doing this way, but that’s one of the beauties of Resolve: there’s often multiple methods for accomplishing the same results.

[Thomas Kaufman]

Marc, I cannot find the Opacity control. You are exactly right in describing the effect I want. I used a power window and tracked the face i want to blur, but only need the effect for part of the clip.
Since I’m a newb, could you explain in a bit more detail?

thanks,

Thomas Kaufman, DP
Washington, DC

[Glenn Sakatch]

1- Window and Track the face for the entirety of the shot, or at least the amount you need with some handles for fading in the effect.

2- Add your blur effect

3- go to the point on your timeline where you want the window to start coming in

4- go the the keyframe editor and turn on keyframes for that node

5- go to the key control (little key button) and set the level to 0 . you should see the white matte in the key window go from white to black.

6- go to the frame where you want the blur up at full level

7- change key level to 100

8- adjust as needed

Glenn

[Michael Gissing]

A quick alternative is to just keyframe the blur value. I’m doing lots of license plate and face blurs at the moment with things coming into and out of shot. I just add a fixed or dynamic keyframe and ramp the blur value from 50 (nothing blurred) to whatever value I like the look of.

This is also handy when something moves in front of the object to blur. The shape remains but the blur ramps off and back on.

[Marc Wielage]

You may find instead of keyframing the blur value itself, go to the Key menu and change the Key Output Gain value to 0. That way, if you change your mind, it’s easier to vary the relative amount of the effect rather than the specific values of the blur. Of course, this works for any correction — LGG, Log, secondaries, curves, keys, blurs, RGB, Offset, whatever.

[Michael Gissing]

Thanks Marc. In this case its blur on blur off so really simple. Your method has more flexibility for more complex nodes.