A High-Throughput Video Modem
We built an independent data channel carried inside an ordinary video call, invisible to H.264 compression — data riding along inside a completely normal-looking video stream.
Three lines of work, one shared subject: what actually happens to a video signal once it's compressed, and how much can be built on top of that — a hidden data channel, or a real-time synthetic performance — without breaking it.
Ordinary lossy video compression is designed to throw away anything a viewer won't notice — which is exactly why hiding a second signal inside it, so it survives that process, is a hard and interesting problem.
We built an independent data channel carried inside an ordinary video call, invisible to H.264 compression — data riding along inside a completely normal-looking video stream.
A blind data channel built directly into the DCT math that H.264 compression itself is built on — engineered specifically to survive that compression rather than merely tolerate it. Developed with support from the Open Technology Fund.
Facial Mimicry Cloning clones real facial motion from a short reference video — a few minutes is enough — and re-drives it from new text or audio, without any generative model. No GAN, no diffusion, no per-subject neural training.
Instead, real captured frames are indexed by their acoustic context and stored in a compact segment library. At playback, the method selects and smoothly blends real frames matching the incoming audio, using optical flow rather than generating new pixels — the face in the output was always a real, recorded face.
The practical result: no GPU dependency, no per-subject training step, and well under 5 seconds of end-to-end latency for a short utterance, running entirely on CPU. A separate silence-handling extension avoids the "frozen face" artifact during pauses, using a small state machine rather than an ad-hoc rule.
A CPU-only synthetic presence is cheap enough to give an AI tutor a real, attentive face without expensive infrastructure behind it — explored further in AI in Education.
A data channel that survives ordinary video compression also survives the kind of network interference that blocks educational content and communication in some regions — the subject of Accessibility & Reach.
We're glad to talk to researchers and collaborators.