Basic principles for good-looking lip sync

Enunciation
We are all different – some people enunciate dramatically (think Jim Carrey), while others hardly move their lips while speaking.

Still, everybody opens their mouth for the vowels A, E, I, O and U – and close it for the consonants B, M, P, F, T, and Y. Everybody lifts the tongue up behind their front teeth for the consonant sounds N, D, L, TH, and T.

Phrasing
The realistic way to do lip sync is this:

• DO NOT animate e-ve-ry sin-gle syl-la-ble
• DO animate the word sounds, or phrases

In real life, people mouth the important word shapes, and blur a good many syllables – instead of moving the mouth in a machine-gun fashion, with a new shape for every single letter, you want to pick out the word shapes in the sentence.

Word shapes
The feeling of the word HOBBIT breaks down, not into 6 letters, but into two or three word shapes:



Similarly, the word HELLO boils down to HE-O (E -> O), and FORTUNE breaks to FOR-UN (O -> U).

Pop
Animation is all about change: an overarching principle is to maximize change between frames. This keeps the viewer interested, and adds vitality.

I'll quote a master: The Animator's Survival Kit, by award-winning director Richard Williams:


(c) Richard Williams and Imogen Sutton, 2001

I love this example – it really shows the difference going from bland to exciting.

Animate before the sound
It doesn't get more important than the 'Sync' in Lip Sync.

The eye accepts animation that leads the audio by one or two frames. But animation that trails the audio looks off-time.

The rule is quite clear:

• DO NOT let animation trail after the audio
• DO animate on time
• DO animate one or two frames ahead of the audio, for effect

So, never be late.

But by all means run a test, and discover if animating a frame in front of the audio looks good in your particular setting. It all depends on the speaker, and intent of the scene.

Giving big vowels a frame extra to register with the eye can indeed improve the look of your animation, and it exists as a rule of thumb with animators, to run a frame or two in front of the audio.

Anticipation
Also, consider the anticipation before a big vowel: Anticipation is a crucial parts of good-looking animation. It is clearly seen in image above, Williams compresses the 'W' consonant face an extra bit in anticipation of popping into the big stretch of the 'O' vowel.

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SUMMARY

• Animate the broad word shapes – not every syllable
• Pop into vowels, cushion off after
• Match, or lead the audio. Never let your animation trail
• Anticipate the stand-out vowels

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Notes

• The Animator's Survival Kit, Richard Williams, 2002

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