Audio-Video Sync Offset Calculator

Audio-Video Sync Offset Calculator

Notice a sync issue between audio and video? This calculator quantifies the offset and tells you exactly which direction to correct it.

Offset (ms) = (Audio Timestamp - Video Timestamp) x 1000

Example

A reference sound event at 10.2s in the audio track, matching visual event at 10.0s in the video:

Offset = 200 ms → Audio is 200 ms ahead - delay audio track to correct

Why Human Perception Is Asymmetric to Sync Errors

Human perception can typically detect audio-video sync errors as small as 45ms when audio leads video, but only around 125ms when audio lags behind video - this asymmetry exists because we're naturally more sensitive to sound arriving before its visual source (like hearing a voice before the mouth moves) than experiencing the reverse delay.

Finding a Reliable Reference Point

Using a sharp, unambiguous sync reference point - a clap, a door slam, a hard consonant sound with a clearly visible mouth movement - gives far more accurate timestamp measurements for this calculation than trying to eyeball sync from continuous, less distinct audio and video content.