What triggers are
Triggers are MIDI messages that LTCast fires at specific timecodes. They let you automate external devices β lighting consoles, media servers, DAWs β directly from the show's timeline without running a separate show controller. Each trigger is a precise, repeatable command that fires every time playback passes its timecode position.
How triggers relate to the timeline
Each song in the setlist has its own independent trigger list. When playback reaches a trigger's timecode, LTCast sends the programmed MIDI message on the configured output port. Triggers fire independently of cue markers on the waveform β they are a parallel output layer. A cue marker is a visual label for the operator; a trigger is an outbound command to another device. Both can exist at the same timecode position without interfering with each other.
What a trigger contains
Each trigger has four required fields:
- Label β a short description shown in the trigger list and in the Calling Script view (e.g., "Lights Q12" or "Resolume clip 4")
- Timecode position β the HH:MM:SS:FF timecode at which the trigger fires
- Trigger type β the protocol used to send the message: Note, CC, PC, MSC, or OSC
- Parameters β the specific values for that type, such as MIDI channel, note number, or OSC address
Trigger MIDI output port
All trigger messages for all songs use the same MIDI output port. Configure it in Settings β Outputs β Trigger MIDI Output. You can use the same port as the MTC output or a separate dedicated port β whichever matches your rig. If no port is selected, triggers are silently skipped during playback.
Common use cases
Triggers are useful any time you need an external device to change state at a precise timecode moment:
- Launching a specific Resolume Arena clip at the start of a song section
- Firing a lighting scene change on an ETC Eos or Chamsys console
- Triggering a sound effect or stem unmute in a DAW
- Sending an MSC GO command to advance a cue on a professional lighting desk
- Starting a video loop on a media server via OSC
Triggers fire on every playback pass. If you loop a section or jump back in the timeline, any trigger whose timecode falls within the playback path will fire again. Plan your trigger list with looping in mind during rehearsal.