---
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title: 'Voice agents with Realtime Video — Sidney Primas, LemonSlice'
description: >-
  An avatar of Teddy Roosevelt holds court in a replica Oval Office, generating
  video continuously for eight hours with no reset, and a second deployment is
  being built to run for sixteen. That duration is the hard part. Sidney Primas
  explains that a real time avatar can only look backward, because the future
  frames do not exist yet, so every block it generates inherits the errors of
  the blocks before it and compounds them. LemonSlice trains with an attention
  mask that enforces this during training rather than discovering it at
  inference, and collapses roughly 30 denoising steps down to a single step to
  hit real time. The less obvious bottleneck is audio. Emotion and facial
  expression turn out to depend on the audio embedding, and most audio encoders
  are trained on audiobooks, which are monotone by construction, so an
  expressive model needs its own. The wider bet is to take a world model and
  point it at humans, paying a harder training and deployment cost up front in
  exchange for full body movement, object interaction, and physics arriving
  closer to free. Two things surprised him. Serving this costs about what
  serving a voice model costs, despite the difference in pixels. And the model
  harness, meaning the orchestration of threads and queues across GPU and CPU so
  that video never stutters through an interrupt, is where he now thinks much of
  the durable value will sit. Speaker info: -
  https://www.linkedin.com/in/sidneyprimas/ Timestamps: 0:00 - Breaking the
  avatar Turing test 2:26 - Teddy Roosevelt in a replica Oval Office 4:40 - Why
  the visual layer matters 5:46 - Pointing a world model at humans 6:58 - One
  image in, any style out, and being the API layer 9:12 - Audio is what makes it
  expressive 10:15 - Making a video model interactive, then real time 12:22 -
  Error accumulation over hours of generation 14:34 - Cost parity with a voice
  model 15:36 - The model harness nobody talks about 16:38 - An emotion engine
  for the next model 19:55 - A single end to end EQ layer 22:09 - Questions:
  internal state, and a real Turing test
canonical: >-
  https://liquidgold.cc/channel/aidotengineer/explore/video/voice-agents-with-realtime-video-sidney-primas-lemo-c8a9ff15ea80
markdown: >-
  https://liquidgold.cc/channel/aidotengineer/video/voice-agents-with-realtime-video-sidney-primas-lemo-c8a9ff15ea80.md
llms: null
parent: 'https://liquidgold.cc/channel/aidotengineer.md'
channel: aidotengineer
updated: '2026-10-24T05:13:33.147Z'
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publishedAt: '2026-08-18T16:00:06.000Z'
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# Voice agents with Realtime Video — Sidney Primas, LemonSlice

An avatar of Teddy Roosevelt holds court in a replica Oval Office, generating video continuously for eight hours with no reset, and a second deployment is being built to run for sixteen. That duration is the hard part. Sidney Primas explains that a real time avatar can only look backward, because the future frames do not exist yet, so every block it generates inherits the errors of the blocks before it and compounds them. LemonSlice trains with an attention mask that enforces this during training rather than discovering it at inference, and collapses roughly 30 denoising steps down to a single step to hit real time. The less obvious bottleneck is audio. Emotion and facial expression turn out to depend on the audio embedding, and most audio encoders are trained on audiobooks, which are monotone by construction, so an expressive model needs its own. The wider bet is to take a world model and point it at humans, paying a harder training and deployment cost up front in exchange for full body movement, object interaction, and physics arriving closer to free. Two things surprised him. Serving this costs about what serving a voice model costs, despite the difference in pixels. And the model harness, meaning the orchestration of threads and queues across GPU and CPU so that video never stutters through an interrupt, is where he now thinks much of the durable value will sit. Speaker info: - https://www.linkedin.com/in/sidneyprimas/ Timestamps: 0:00 - Breaking the avatar Turing test 2:26 - Teddy Roosevelt in a replica Oval Office 4:40 - Why the visual layer matters 5:46 - Pointing a world model at humans 6:58 - One image in, any style out, and being the API layer 9:12 - Audio is what makes it expressive 10:15 - Making a video model interactive, then real time 12:22 - Error accumulation over hours of generation 14:34 - Cost parity with a voice model 15:36 - The model harness nobody talks about 16:38 - An emotion engine for the next model 19:55 - A single end to end EQ layer 22:09 - Questions: internal state, and a real Turing test

Canonical: https://liquidgold.cc/channel/aidotengineer/explore/video/voice-agents-with-realtime-video-sidney-primas-lemo-c8a9ff15ea80 · Channel: [AI Engineer](https://liquidgold.cc/channel/aidotengineer.md)

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