LTC Timecode Generator

Knowledge Base

How to Use the LTC Generator

The LTC Generator creates Linear Timecode (LTC) audio, a special encoded timecode signal playable as audio. Use this to synchronize cameras, recorders, and external devices during film and video production without needing expensive timecode hardware.

What Is Timecode?

Timecode is a precise timestamp (HH:MM:SS:FF, hours, minutes, seconds, frames) encoded into video or audio. It synchronizes multiple recording devices to a common reference point. LTC is timecode encoded as audio you can record into a secondary audio channel.

Why Use LTC?

• Multi-Camera Sync: Jam all cameras to the same timecode, then sync in post-production by matching timecode.
• External Recording: Record audio to external recorder (Rode Wireless GO II, Zoom H6) jammed to camera timecode.
• Slate Replacement: Instead of clapper board, cameras and recorders show matching timecode, faster setup.
• Post-Production: Automatic sync of video and audio based on matching timecode.

Setup Process

1) Set your camera's timecode (usually in menu, set to 24-hour format and specific start time). 2) Generate LTC audio from generator tool with matching settings. 3) Feed LTC audio into timecode input on recorders. 4) "Jam sync" recorders (usually a button press) to lock timecode. 5) All devices now share timecode, sync in post by timecode.

FAQ

Q: Do I need LTC for small productions?
A: For single-camera or local recording, no. For multi-camera, external audio, or professional work, LTC saves hours in post-production.

Q: What frame rate should I use?
A: Match your video frame rate (24fps, 25fps, 30fps, 60fps). Mismatch causes sync drift.

Using timecode on an audio track

Linear timecode encodes a timecode value as an audio signal, so any device able to record audio can record timecode. That is the whole point of it. A camera with no timecode input, or a recorder without dedicated support, can still carry synchronised timecode on a spare audio channel.

The signal is not meant to be heard. It is a harsh, buzzing tone occupying a full audio channel, so it goes on a channel carrying nothing else and gets removed before any mix. Recording it onto the same channel as dialogue makes both unusable.

Set the frame rate to match the recording exactly. Timecode generated at 25 frames per second against footage shot at 23.976 drifts steadily and produces the most confusing category of sync problem, because everything lines up at the start and separates gradually. This is a settings error rather than a technical limitation.

Understand what jam sync does and does not give you. Feeding timecode to a device sets its clock to match, after which it runs on its own internal clock. Those clocks drift, so a device jammed in the morning is measurably off by the afternoon, and re-jamming periodically through a long day is normal practice rather than a sign of faulty equipment.

Level matters more than it appears to. Timecode recorded too quietly reads unreliably, and recorded too loudly distorts and reads unreliably in the other direction. Setting it and checking a decode before the shoot takes minutes, and discovering unreadable timecode during the edit costs far more than that.

Vocabulary

LTC. Linear timecode, a timecode value encoded as an audio signal so it can be recorded on any audio track. Defined in SMPTE 12M and still widely used because it needs no dedicated hardware support.

Jam sync. Feeding timecode into a device so it sets its internal clock to match, then runs independently. Clocks drift, so periodic re-jamming through a long day is standard practice.

Free run and record run. Free run advances timecode continuously like a clock. Record run advances only while recording, producing continuous timecode across takes on one card. Different jobs suit different modes.

Drift. The gradual separation between two clocks running independently. The reason devices jammed to a common timecode at the start of a day no longer agree by the end of it.