Syncing camera and sound clips in Video by Zaweba

Good sound is often recorded separately. A camera's built in microphone is rarely the best in the room, so many people use a separate recorder or a clip on microphone and bring the sound together with the picture later. Video by Zaweba has two tools for this: synchronise, which lines clips up on the timeline, and merge, which links a camera clip with its separate sound.

Synchronise

Select the clips on the timeline that should line up, then choose Synchronise. You pick what to line them up by: start, end, timecode, the first clip marker, or sound.

Start and end are the simplest. They line clips up by their first or last frame, which works when every device started or stopped recording at the same moment, which is rarer than people hope.

Timecode works when the devices shared a time code, as many professional cameras and recorders can.

First clip marker works when you have placed a marker on the same moment in each clip, such as a hand clap or a clapperboard. Put a marker on the clap in each clip, synchronise, and they line up.

Sound is the most useful for everyday work. Every device hears the same room, so the app compares the sound in each clip and lines them up. Sound is matched to the millisecond, which is finer than a single frame, so speech lines up with lips precisely.

Merge

Merge links a camera clip with a separately recorded sound file. Once merged, the picture and the good sound travel together as one item. Trim the picture and the sound trims with it. Move it and both move.

This is how you work with dual system sound. Sync the camera clip and the recorder's file, merge them, and from then on you edit with clean sound attached, without worrying about it slipping out of step.

A typical workflow

Film with the camera recording its own sound as a guide, and a separate recorder on the subject. Clap once at the start of each take if you can.

Import both. Put the camera clip and the recorder's file on the timeline. Select both and choose Synchronise, by sound. The app lines them up. Play the result and check the lips.

Merge the two. Now the camera clip carries the recorder's sound. Mute or remove the camera's own guide sound if you no longer want it.

Repeat for each take. With several takes, it can be quicker to sync and merge them all before you start editing, so the edit begins with clean sound everywhere.

Getting good results

Sound sync works best when both devices recorded the same sounds clearly. A camera far across a noisy room may struggle to match a close microphone. A sharp clap at the start gives a clear point to match on and helps every method.

Check sync on a close shot of someone speaking. Eyes are very sensitive to lips that are even slightly out, and that is where a problem shows first.

If a long recording drifts apart over time, which can happen when two devices record at slightly different speeds, synchronise at the start of each section rather than once for the whole recording.

How it relates to multi-camera editing

Synchronise and merge deal with clips on the timeline. When you have several cameras of the same event, the multi-camera tool lines them up as it builds the multi-camera source, using similar choices including sound. Use synchronise and merge for a camera plus a recorder; use multi-camera when you want to switch between several angles.

Clean sound makes a bigger difference to a film than almost anything else. Video by Zaweba makes pairing it with your picture a few clicks rather than a fiddly manual job.