Sync to Timecode (LTC)

Last updated 5 May 2026

Backstage can chase incoming LTC (Linear TimeCode) timecode, locking its sequence playhead to an external timecode source in real time. This is used when a show controller, audio playback system, or lighting desk sends timecode on an audio output that Backstage needs to follow.

Before you start

  • Your LTC source is connected to an audio input on the Backstage server
  • You know which audio device and input channel carries the LTC signal
  • You have a sequence set up in the Sequencer that should chase the timecode

Steps

1. Add an Audio LTC node

Right-click the canvas → Time → Audio LTC.

Setting

Description

Values / Range

Device

Select the audio input device that receives the LTC signal.

Dropdown

Channel

Select the input channel carrying the LTC (channels are numbered from 1).

Integer (1+)

The node decodes the LTC signal in real time and emits two outputs:

Output

Type

What it carries

Timecode

Timestamp

The decoded timecode position in microseconds

Action

String

Play when timecode is running, Pause when it stops

2. Add a Sequence node

Right-click → Sequence → Sequence. Select the sequence that should chase the timecode.

3. Connect the nodes

Connect the Timecode output to the Sequence's Set time input.

Optionally connect the Action output to the Sequence's Action input. This starts the sequence automatically when timecode runs and pauses it when timecode stops.

4. Verify the chase

Start your timecode source. The Sequence node's time display updates to match the incoming timecode.

The sequence frame rate set in the Sequencer should match the frame rate of the LTC source (25 fps, 29.97 fps, or 30 fps) for correct timecode interpretation.

Common Mistakes

  • Sequence is not chasing timecode — wrong audio device or channel is selected on the LTC node. Use a third-party audio meter to confirm the LTC signal is arriving at the chosen input.

  • Sequence pauses immediately when timecode starts — the LTC signal is intermittent, triggering the automatic Pause after approximately 100 ms of silence. Check cable quality and input level.

  • Playback is offset by a consistent amount — the sequencer frame rate does not match the LTC source frame rate. Match them first, then use the Offset setting for fine-tuning.

Tips

  • If the sequence is consistently ahead or behind by a fixed amount, use the Offset setting on the Audio LTC node to shift the timecode in milliseconds.

  • If timecode stops arriving for approximately 100 ms, the Action output automatically sends Pause — connecting Action to the Sequence node gives you automatic chase-and-park behaviour.

  • ASIO audio devices provide the lowest latency LTC input. Standard WDM devices also work.

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