Put every recording in sync
Line up every camera and microphone from one event. Let the app align them automatically, or do it by hand.
For researchers, and anyone else with recordings to line up
Several recordings, one event, and none of them start at the same time.
A room filmed from two corners. An interview recorded on a camera and lapel mics. Fieldwork filmed 'in the wild'. Each device started recording at a different moment, so before you can compare or analyse the recordings, you have to line them up.
Professional editing software
Expensive, and made for a different job
Editing suites can sync clips. They also cost money, take weeks to learn, and are built to cut everything into one film. Getting each recording back out as its own synced file is an afterthought.
Video Alignment Tool
Automatic or manual, and free
Add your recordings and press one button to try automatic alignment. The app compares the audio in each track and works out where they overlap. If it gets one wrong, move it by hand. Then export every file trimmed to the same start and end, so a moment has the same timestamp in every file.
How it works
Four steps from a folder of files to synced recordings
Add your recordings
Video from as many cameras as you used, plus audio from separate recorders. If a camera split one recording into chunks, merge them first.
Press Align
The app compares the sound in each recording and slides every one into place on a shared timeline.
Check it
Play everything together and read how confident each match is. If the automatic alignment got a track wrong, move it by hand.
Export
Every file comes out the same length, starting and ending at the same instant, in the video format you choose.
What you get
Built for lining up recordings, and nothing else
Automatic alignment from sound
No clapperboard needed. The app matches ordinary sound that every microphone picked up, like voices, footsteps and room noise, and reports how confident it is in each match.
Fixes clocks that run fast or slow
Some recorders keep poor time. One that gains two seconds an hour is badly out of step by the end of a long session. The app measures the drift and corrects it, so the end lines up as well as the start.
Sync by marking a moment
When the sound is too different to compare, mark the same instant in each recording yourself. A clap works, or a door closing, or a even a loud laugh. The app lines the recordings up from your marks.
Watch every angle at once
All cameras play side by side in step, with sound from whichever microphones you choose. Zoom into one view to check a detail. If a format won't play in the app, it makes a lightweight preview copy for you, called a proxy.
Exports that stay in sync
Every exported file starts at the same instant and is exactly the same length. Keep each file's original quality, or set the format, size, frame rate and quality per recording. Save settings you reuse as presets.
Joins split camera files
Action cameras like GoPro split long recordings into several files. Merge & Add Media sorts them back into recording order and joins them into one file. It can usually do that without re-encoding, so the quality stays the same.
Opens MP4, MOV, MKV, AVI, MTS/M2TS (AVCHD), MXF, WebM, WAV, AIFF, MP3, FLAC, M4A and more. Media processing uses the open-source ffmpeg.
Accuracy
Check the alignment yourself
If your analysis depends on when things happened, you need to know the recordings really line up. The app shows how it reached each result, so you can see which recordings to double-check.
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A report for every runEach automatically aligned recording gets a confidence score, the number of moments it matched on, and any drift correction. If a match looks doubtful, the report says so.
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Matched moments stay on the timelineThe app leaves a marker at each one. Jump to any marker to see and hear whether the recordings agree.
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Nothing is final until you exportYou can undo any change, the app autosaves your project, and it never modifies your original files.
Accuracy in testing*
| Measured | Result |
|---|---|
| Start time | Within 1 ms |
| Clock drift | Within 25 ms per hour |
| How far apart recordings can start for auto-alignment to work | 5 minutes by default, adjustable in Preferences |
* Checked against simulated recordings of one event made by five "microphones" with known start times, clock speeds, room echo and background noise.
Sync your next session in minutes
Free to download. No account, no subscription, no upload.