Voice agents with Realtime Video — Sidney Primas, LemonSlice
Aug 18, 2026 · 26:36
LemonSlice CTO Sidney Primas explains how his startup builds real-time video avatars by pointing world models at humans. A Microsoft partnership put a Teddy Roosevelt avatar in a replica Oval Office, generating continuously for eight hours with no reset. He argues audio embeddings drive emotion, and because avatars only look backward, errors compound, so LemonSlice trains with an attention mask and collapses roughly 30 denoising steps to one. He says serving video costs about the same as a voice model, and that the model harness, which orchestrates GPU/CPU threads and queues to avoid stutters, holds much durable value. He predicts an emotion engine for better reactions and an end-to-end EQ layer within two or three years, taking user video and audio and outputting avatar video and audio.
