How long a window of sound does it take to sync two drifting cameras, and how often must you redo it?

What it found

Synthetic speech-like audio (shared source, independent noise, optional reverb), per-window GCC-PHAT delay (100–4000 Hz) and a Theil–Sen line over 12 windows in 1 h at 40 ppm clock error. With 2 s windows the fit is below 0.02 ms from −10 dB SNR up and fails completely at −15 dB; 5 s windows hold to −15 dB. A sync made once at the start drifts one 30 fps frame (33.3 ms) in 833 s at 40 ppm (144 ms after an hour; analytic ppm × time reproduced exactly). Reverb at −10 dB direct-to-reverberant adds 4adds 4–8 msndash;5 ms (median). Not from real recordings: the audio and the exact delay are synthetic and the ppm values are swept, none sourced (no datasheet reachable).

Paper, code and results

• README and method
• Experiments and results
• Code
• Tests

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Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.