Sync audio to video by waveform
Recorded sound separately (Zoom, Tascam, a lav, a phone) or with two cameras? Drop the camera file and the audio file: we match the waveforms and give you the exact offset and an aligned WAV to drop at 0:00. No clapper needed.
Offset
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Questions
Does it need a clap or slate?
No. It matches the sound itself, so any shared sound works: speech, room noise, music. A clap just makes the match more certain.
How accurate is it?
Within a millisecond on clean overlapping audio, far finer than one video frame (33-42 ms). It also tells you when the match is weak.
Can it fix audio that drifts out of sync over a long take?
Not yet: it finds one offset. Long takes from devices with cheap clocks can drift a frame or two per hour.