Guide
How to sync podcast cameras and audio without a clapperboard
By Lev PerlmanUpdated 3 min read
To sync podcast cameras and audio without a clapperboard, make sure every camera records some sound (even from its built-in microphone), then use your editor's audio sync, which lines the recordings up by comparing their waveforms. A clap at the start makes the job easier and gives you a visible check. For long recordings, watch for drift and re-sync if the sound slowly slips.
The three ways to sync
| Method | How it works | Best for |
|---|---|---|
| Clap or slate | A sharp sound and a visible action at the start; line up the spike by hand or with audio sync | Any setup, as a backup and a visual check |
| Waveform (audio) sync | The editor compares the recordings' audio and finds the offset | Most podcasts: no extra kit needed |
| Timecode | Every device stamps the same clock time; the editor aligns by it | Larger shoots with timecode-capable gear |
How to record so syncing is easy
- Record sound on every camera. The built-in microphone is enough. It is only used for syncing.
- Start everything before anyone speaks. Begin all recordings, then start the conversation.
- Clap once on camera. One sharp clap, seen by every camera, gives a clear spike to line up and a visual check.
- Avoid stopping and starting. Every restart creates a new set of files to sync. If you must stop, clap again when you restart.
- Know how your camera splits files. Many cameras break long recordings into several files. Keep them in order and join them, or sync each in turn.
How to sync in each editor
- Final Cut Pro: create a multicam clip and turn on Use audio for synchronization, which fine-tunes the alignment using each angle's waveform.1
- Premiere Pro: create a multi-camera source sequence and choose Audio as the synchronize point.2
- DaVinci Resolve: create a multicam clip and choose Sound for angle sync. Blackmagic Design lists syncing by audio waveform, timecode or in and out points.3
Our multicam editing guide walks through each step.
What is drift, and how do you fix it?
Cameras and audio recorders each keep time with their own clock, and no two clocks run at exactly the same speed. Over a long recording the difference adds up, so audio that was in sync at the start can be noticeably out by the end. It shows as lips moving slightly before or after the words.
To fix it:
- Check the end of the recording, not just the start, before you edit.
- Split and re-sync a long recording into sections, syncing each section separately.
- Stretch the audio by the tiny amount needed to match the camera's length, using your editor's speed or retime controls on the audio clip.
- Record shorter takes if your equipment drifts badly.
What to do when audio sync fails
- Check that every camera has audio. A camera with no sound cannot be synced by waveform.
- Trim long silence or noise from the start of each clip, so the editor compares the conversation.
- Make sure every file in the selection is from the same session.
- If one camera split its recording, sync each part, or join them first.
- As a last resort, line up the clap by eye and sync from that point.
Sync handled for you
podswitch syncs every camera and microphone by comparing its sound with a reference recording, so you do not need timecode or a clap. It then makes the edit from the microphones and opens it in Final Cut Pro, Premiere Pro or DaVinci Resolve with everything lined up. If your cameras write timecode, it is kept in the Final Cut Pro project. The recording guide covers what to capture.
Sources
-
Apple, Final Cut Pro User Guide, "Create multicam clips". https://support.apple.com/guide/final-cut-pro/create-multicam-clips-ver23c764f1/mac ↩
-
Adobe Help, "Create a multi-camera source sequence". https://helpx.adobe.com/premiere/desktop/edit-projects/set-up-multi-camera-sequences-for-editing/create-a-multi-camera-source-sequence.html ↩
-
Blackmagic Design, DaVinci Resolve Edit page. https://www.blackmagicdesign.com/products/davinciresolve/edit ↩
Common questions
Do I need timecode to sync a podcast?
No. Waveform sync lines recordings up by their sound, which works with any cameras as long as each one records some audio. Timecode helps on long shoots with many devices, but it needs cameras and recorders that support it and a way to keep them in step.
Why does my audio slowly go out of sync?
Each device's clock runs at a very slightly different speed, so over a long recording the gap between them grows. It is called drift. Fix it by splitting the recording and re-syncing each part, or by stretching the audio to match the camera.
Why did audio sync fail in my editor?
The usual causes are a camera with no audio, very long stretches of silence or noise before the conversation, a different recording entirely in the selection, or a camera that split its recording into several files that were not joined first.