How to Sync Several Camera Clips to One Long Audio Recording

Interviews, events, weddings and talks are often recorded this way: the sound recorder rolls once for the whole session, while the camera stops between takes or splits a long recording into several files. You end up with one long audio file and a folder of clips, and every clip sits somewhere inside that recording.

Finding each one by eye means scrubbing the waveform clip after clip. Waveform sync does it for you, and the same tool can hand every clip back with the recorder's sound already in place.

Step by step

1. Open the audio sync tool and drop the recorder's file as the first file. Put the long recording first: each clip is then looked for inside it.
2. Drop the first camera clip as the second file, and the rest under More recordings or clips.
3. Leave Correct clock drift ticked (more on that below).
4. Press Find the offset. The table shows where each clip starts in the recording, the drift it measured and how confident the match is.
5. Press Synced video for each clip. Every clip comes back as its own MP4 with the recorder's sound in place of the camera's. The picture is copied, not re-encoded, so nothing is lost. In Chrome and Edge you pick a folder and each clip is saved there as soon as it is done; other browsers download them one by one.

Nothing is uploaded: the files are read and written in your browser.

Why long clips need drift correction

Two devices never run at exactly the same speed. A difference of 20 to 100 parts per million is common, which adds up to 70 to 360 ms over an hour. One frame at 30 fps is 33 ms, so a 30-minute clip at 50 ppm ends about 90 ms (nearly three frames) out of sync even though it started perfectly.

With Correct clock drift on, the offset is measured near the start and near the end of every clip that is at least two minutes long, and the recorder's sound is stretched to match, so the end of the clip is as tight as the start. Shorter clips get an offset only, which is all they need.

Prefer to work in your editor?

Download the Timeline XML instead. It places every original file at its offset on one timeline: in Premiere Pro use File → Import, in DaVinci Resolve File → Import → Timeline, and point it to the files the first time. The aligned WAVs (one per recording, in a zip) are the other option: each starts with the first file, so it drops in at 0:00.

When a clip can't be matched

• The camera's microphone recorded almost nothing (switched off, or far away in wind).
• The clip was shot while the recorder wasn't running, so there is nothing to match.
• The camera and the recorder heard very different things, for example a lav under a jacket in a loud room.

Clips with a weak match are left out of the synced videos and named in the status line, rather than placed at a guess. Check those by ear, or sync them on their own.

One practical limit: the recording is read into memory in full, so on a laptop with little memory, split a recording of several hours into parts first.

Try the tool

Free, no upload. Get the extension for transcripts beside YouTube and TikTok videos, or see what Pro adds.