Smoothing over time

Why a corrected face can flicker

FaceTweak redraws the face fresh on every frame. Each frame on its own looks right, but tiny differences between one frame and the next can add up when the shot plays: the face square shifts by a hair, a lip edge lands a little to the left. In motion, those differences show as shimmer, jitter or a gentle wobble.

The Temporal section fixes this. “Temporal” just means “over time”: these controls let each frame look at the frames around it, so the face moves smoothly instead of being worked out from scratch every time.

Which control to try first

Turn on one control at a time and watch the shot play before adding another. It’s easiest to finish your slider changes first: each time you change a slider, the nearby frames have to be worked out again.

Steadying the face

Temporal ConsistencyOff · Standard · Strong · default Off

Steadies the square FaceTweak takes around the face, and how the redrawn face lines up with the real one, by comparing neighbouring frames in the same shot. The redrawn face then stays locked to the head instead of jittering against it.

Start with Standard. Use Strong if a slight jitter remains.

Smoothing the mouth and eyes

These two sliders calm the extra movement that your edit adds. The actor’s real movement is kept: FaceTweak follows how the face actually moves through the shot, so a turn of the head or a real word isn’t delayed or blurred. Only the jitter that the edit introduced is smoothed away.

Mouth Motion Smoothing0 to 100 · default 0

Smooths the movement your edit adds to the mouth. 0 is off and 100 is the strongest. A good place to start is 50: raise it through a troublesome section, and keyframe it back down where the motion already looks right.

Eye Motion Smoothing0 to 100 · default 0

The same for the eyes. Each slider works on its own, so you can smooth the mouth without touching the eyes.

For the curious, here’s how they work. FaceTweak looks at up to four frames before and after the current one. It carries the position of the lips or eyes from each of those frames along with the real motion of the face, then takes a careful consensus, ignoring any frame where the features were clearly found in the wrong place. Small, random differences cancel out; real motion stays.

• It knows when to step aside. At a blink, a mouth opening or closing, a cut, or a frame where the face can’t be followed reliably, the current frame keeps its own shape.
• Any amount costs about the same. 10 and 100 look at the same number of frames, so turning it up doesn’t make renders slower.
• It doesn’t fix everything. It smooths shape and position, not brightness, so it won’t remove flicker in tone or colour. Very high values can also soften movement you wanted.
• These sliders work on their own: they don’t need any other Temporal control switched on.

Keeping fine detail steady

Detail ConsistencyOff · Standard · Strong · default Off

Keeps fine detail steady from frame to frame, and keeps the parts of the face you didn’t change closer to the original footage. Use it when texture such as teeth, lashes or skin seems to sparkle or crawl.

Standard compares each frame with one frame either side. Strong compares with two either side: steadier, but slower. Both add render time and use more memory. On close-ups, it also steadies the extra detail FaceTweak adds there (see Close-ups and 4K).

Matching the camera’s motion blur

A real camera blurs anything that moves while its shutter is open. The pixels in your footage already have that blur. Anything FaceTweak creates, such as teeth in a mouth you opened, is perfectly sharp. On a moving face, that sharpness can look like a sticker on top of the picture. Motion Blur gives FaceTweak’s additions the same blur as the footage around them.

Motion BlurOff · Invented Detail · Invented Detail and Face · default Off

• Invented Detail is for close-ups, where FaceTweak keeps the real skin and only creates what the camera never saw. It blurs only what FaceTweak created. Real pixels from your footage are never blurred twice.
• Invented Detail and Face also blurs the redrawn face on everyday-size faces. Use it only if the face looks sharper than the rest of the picture. The redraw starts from your real frame, so it usually carries some of the camera’s blur already.

Shutter Angle0° to 360° · default 180°

How much blur, in the same terms cameras use. 180° is the usual setting for film and most video, and it’s the right choice if you don’t know. Higher values blur more, and 0° means no blur. Match the camera if you know its setting. This control only appears while Motion Blur is on.

Motion Blur follows how the footage itself moves. Movement that exists only because of your keyframes, such as a mouth you animated opening with AAA, isn’t blurred. The first and last frames of a clip, and frames next to a cut, have only one neighbour to compare with, so they get a little less blur.

A word on render time

Each Temporal control asks FaceTweak to look at more frames, so they add up. Mouth and Eye Motion Smoothing look the furthest (four frames each way) and are the most demanding. Detail Consistency and Motion Blur look one or two frames each way. If playback becomes too slow while you work, turn on Resolve’s render cache for the clip (Playback › Render Cache), or switch the Temporal controls on only once the rest of the shot is finished.