When picture and sound are recorded separately - a camera and a separate audio recorder, the classic dual-system setup - you need to line them up before editing. Lightworks synchronises clips by timecode or on a common parked frame, and the result is a sync clip you can cut with like any other.
Sync methods
The Synchroniser's Synchronise by option offers three ways to align clips:
| Method | How it works | Best when |
|---|---|---|
| Clip labels | Aligns clips by their source timecode | The camera and recorder shared (jam-synced) timecode |
| Playout timecodes | Aligns clips by their playout timecode | The clips carry a common playout timecode |
| Current frames | Aligns two clips on the frame each is currently parked on | There is no common timecode, but there is a common reference such as a clapperboard |
Note: Current frames needs exactly two clips selected - one picture, one sound. The timecode methods can sync any number of clips in one pass.
Sync by timecode
If your camera and audio recorder were jam-synced to the same timecode, this is the most reliable method:
- Select the picture and sound clips you want to sync.
- Open the Synchroniser and set Synchronise by to Clip labels.
- Set the Picture clip label and Sound clip label so Lightworks knows which clips pair up.
- Confirm to create the synced result.
Because timecode is exact, this aligns clips to the frame with no manual work. Two extra options help with real-world material:
- Sound offset (frames) - apply a constant offset to the sound if the recorder's timecode was consistently ahead or behind.
- Match date (if present) - use the recording date as well as the time, so takes from different days with repeating timecode don't mis-match.
Sync by a common frame
Without matching timecode, sync on a common reference - the clack of a clapperboard, a hand clap, or any unmistakable picture-and-sound event:
- In the picture clip, park the playhead on the exact frame of the reference.
- In the sound clip, park on the same moment.
- Select both clips, set Synchronise by to Current frames, and create the sync.
Lightworks lines the clips up on the frames they are parked on.
Tip: A clapperboard exists precisely to give you a sharp, single-frame picture-and-sound event to sync on. If there's no slate, look for any sudden sound with a clear visual cause.
The Synchroniser
The Synchroniser brings separate tracks together based on your chosen method and their track labels, producing a sync clip (a sync-type subclip). You also control the shape of the result:
- Result starts at / Result ends at - trim the result to the earliest or latest track, or to the first or last picture, depending on whether you want every frame of everything or only the fully covered section.
- Produce result as - what kind of item the sync becomes.
The sync clip plays its picture and sound together and behaves like any other clip in the Content Manager - you can mark it, subclip it, and edit it into a sequence. Sync clips are flagged so you can tell them apart from plain clips and subclips (see Logging and subclips).
Working with dual-system sound
For a dual-system shoot:
- Best case - jam-sync the camera and recorder to the same timecode on set, then sync by Clip labels in the edit.
- No common timecode - record a clapperboard or clap at the start of each take and sync by Current frames.
- Once synced, leave Clip Link on so picture and sound select and move as one on the timeline. Material you lay in together is linked automatically; where you need to link picture to sound that arrived separately, select both and use Link (see Selecting and moving material).
Checking sync in the viewer and timeline
- Watch a sync reference (the clap) at full speed and frame by frame to confirm picture and sound land together.
- On the timeline, Lightworks tracks sync loss and shows an indicator when tracks slip out of sync - click it to fix the slip, or
Shift+click to accept the new positions as intended. An offset only means something between linked clips that came from the same source, so that is where it is reported; a music track sitting under a shot is not "out of sync" with it. - Listen on headphones for echo or flam, which reveals a sync that is a frame or two out.
Fixing sync problems
- A consistent offset - the whole take is out by the same amount. Re-sync on a clearer reference, or slip the sound against the picture by the offset.
- Drift over time - picture and sound were recorded at slightly different rates. Check that clip and project frame rates are correct (variable frame rate media is a common cause; see Importing media).
- Lost sync while editing - use Clip Link so picture and sound are selected and moved as one, and leave Track Sync on so trims and inserts hold the other tracks in step (see Trimming).