Synchronization / Technical guide
Timecode for Live Visual Production
Timecode answers one question: where are we on the timeline? It gives frames an address—hours, minutes, seconds and frames—so independent systems can refer to the same moment. It does not, by itself, guarantee that video outputs refresh together or that audio sample clocks remain phase-aligned.
Position is not the same as clock
This distinction prevents many synchronization problems. LTC or MIDI Timecode can tell a playback application to move to a position. Genlock aligns video timing to a reference. Frame lock aligns multiple display outputs. Word clock aligns digital-audio sampling. A production may use more than one of these layers because each solves a different problem.
Calling every reference “sync” can hide the actual failure. If two playheads point to the same frame but their outputs tear across a multi-screen canvas, investigate output synchronization. If the image follows the track but slowly drifts in relation to audio, inspect frame rates, clocks and the complete signal path—not only the timecode number.
The basic timecode workflow
- Choose one master source. Establish which department or device owns the timeline and document the agreed frame rate.
- Distribute a known signal. LTC is commonly carried as an audio signal; MTC carries time information as MIDI messages. The receiving equipment must support the chosen format.
- Match the receiver. Set the input, frame rate and any offset in the playback application. A regular jump or correction can indicate a frame-rate mismatch.
- Build intentional offsets. Separate songs or show sections into clearly documented hour ranges so one cue cannot accidentally call the wrong media.
- Test discontinuities. Jump forward, jump backward, stop the source, remove the signal and restore it. A system is not tested until its failure behavior is known.
What timecode should control
Timecode is strongest when a finished piece of media must follow a finished timeline. A song intro, a tightly edited sequence or a repeated show segment can benefit from exact positional reference. It is less useful for visual material that must respond freely to a performer or to an audience.
In Resolume Arena, incoming SMPTE can drive a clip’s playhead, but it does not trigger that clip. The clip must already be active in an output layer. That small distinction belongs in the cue plan: timecode positions media; a separate action may still be responsible for making the media visible.
Frame rate is part of the contract
Write the timecode frame rate into the technical documentation. Do not assume that a file labeled “30” and a 29.97 timecode source are equivalent. Drop-frame and non-drop-frame notation also describe how frame numbers relate to clock time; they do not change the physical rate at which frames are played.
The receiver must match the incoming timecode rate. For smooth results, the media and output workflow should also be designed around compatible rates, but those are separate configuration decisions.
Network clocks are a different layer
PTP and NTP distribute clock information over networks. Dante uses PTP for clock synchronization inside a Dante network. That does not make Dante a generic SMPTE timecode distributor, and NTP should not be described as a frame-accurate replacement for LTC, MTC or a dedicated video reference. Name the exact protocol and the exact device function instead of grouping them under “network sync.”
A practical test sheet
- Master source, format and frame rate.
- Signal path, adapters and audio-interface channel.
- Input level and clean isolation from program audio.
- Clip offset and expected first visible frame.
- Behavior on stop, signal loss, jumps and restart.
- Manual trigger and playback fallback.
- Owner of the decision to return from backup to primary.