Lip-Sync, Latency, and Motion — What Actually Makes an AI Avatar Feel Real

Sync accuracy

Aim for <80ms drift between phoneme and mouth movement. Above 120ms, the visitor stops trusting the face.

Response latency

First word out under 2.5s. Anything above 4s and the visitor thinks it froze.

Micro-motion

Real humans blink, breathe, shift. HD mode adds those cues at the cost of a few dozen ms — worth it for high-ticket pages.