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How to fix audio and video sync drift for beginner editors
Sync that starts fine but drifts by the end of the take is a common beginner problem. Here is why it happens and how to fix it.
Few things look more amateur than dialogue that starts in sync and slowly drifts away. It usually happens with long takes, consumer cameras, or mixed sample rates. The fix is easier once you know the cause. Most drift is caused by one of three things: mismatched sample rates, different frame rates, or recording devices with slightly different clocks.
Check sample rates first
If the camera recorded audio at 44.1 kHz and the recorder at 48 kHz, the files will run at slightly different speeds. When you align them at the beginning, the longer the take, the more they drift apart. Convert both to the same sample rate before syncing. Use the project sample rate, usually 48 kHz, for everything.
Verify frame rate and timecode settings
A camera set to 23.976 fps and a recorder set to 24 fps will drift over time. The same happens with drop-frame versus non-drop-frame timecode. Make sure the timeline and the footage match the intended frame rate. If the camera and recorder use different clocks, sync by waveform and avoid relying on timecode alone.
Fix drift in the timeline
If the audio starts in sync and ends late, stretch the audio clip slightly. In Premiere, right-click the clip and choose Speed/Duration. In Resolve, use the retime controls in the Edit page. You only need tiny adjustments, often less than 0.1 percent. Always check a known sync point at the end of the clip after adjusting.
Prevent drift on the next shoot
- Set every device to 48 kHz sample rate.
- Match frame rate across camera, recorder, and timecode generator.
- Jam timecode between devices at the start of the day and after battery changes.
- Record a slate or clap at the beginning and end of long takes to verify sync.