MTC Output
MTC (MIDI Timecode) carries SMPTE timecode over a MIDI connection. While a song plays, LTCast sends it continuously so any MIDI-capable device — a DAW, lighting console, or media server — can lock to the current position and follow every seek.
Pro. LTCast sends MTC, Art-Net and OSC timecode only while the session is Pro (a Pro licence or an active trial). Without Pro — the free version, an expired trial or a lost licence — no MTC timecode goes out: the MTC light in the status bar turns amber and reads Needs Pro, and Pre-Show Check warns about it.
Setting up a MIDI output port
Choose the MTC port in Settings → Devices → MTC Output (MIDI). The selector lists all available MIDI output ports on the system. The MTC light in the status bar turns on once a port is selected.
If you are routing MTC to software on the same machine, create a virtual MIDI port first:
- Windows — install loopMIDI (free, Tobias Erichsen). Create a port in loopMIDI, then select it in LTCast. Open the same port as MIDI input in your DAW or lighting software.
- macOS — open Audio MIDI Setup → Window → Show MIDI Studio → double-click IAC Driver → check Device is online → add a port. Select the IAC bus in LTCast.
For physical MIDI hardware, connect a USB-MIDI interface and select its output port in LTCast.
Quarter-frame and full-frame mode
Pick the mode in Settings → Outputs → MTC Mode.
- Quarter-frame (recommended) — the standard mode for continuous sync. LTCast sends 4 quarter-frame messages for every SMPTE frame, evenly spaced across the frame. One complete timecode value is spread over 8 messages, so a receiver needs two frames to read it. At 25 fps that is 100 messages per second; at 30 fps, 120. Use this for all normal operation.
- Full-frame (legacy) — LTCast sends one SysEx message each time the frame number changes, so at 25 fps that is 25 messages per second. Each message carries the complete timecode. It exists for older devices that cannot read a quarter-frame stream; use it only when a receiver explicitly requires it.
New installs start in Quarter-frame. A show file saved by a very old version of LTCast, from before this setting existed, opens in Full-frame, so check MTC Mode after opening an old show.
In both modes LTCast also sends one full-frame message when you press play, when you seek, and when you select the MTC port, so that receivers can locate before (or as) the stream starts.
Frame rates
MTC can express four frame rates. LTCast maps the rate it is running at onto them:
| LTCast rate | MTC rate sent |
|---|---|
| 23.976 or 24 fps | 24 fps (MTC has no separate 23.976 code) |
| 25 fps | 25 fps |
| 29.97 fps drop-frame | 29.97 fps drop-frame |
| 30 fps | 30 fps non-drop |
| Any other rate | 30 fps non-drop |
The MTC frame rate follows the frame rate LTCast is running at — the file's LTC, the rate you forced, or the TC Generator rate. Make sure the receiving device is configured to the same frame rate. A mismatch causes the receiving device to run at the wrong speed or refuse to lock.
MTC and MIDI Clock on the same port
The same MIDI port carries both MTC messages and MIDI Clock pulses. You do not need to configure two separate ports. Most MIDI-capable software correctly handles both message types on the same port and assigns each to its appropriate engine (timecode vs. tempo sync).
Panic
Panic sends a zero full-frame message on the MTC port, plus All Notes Off and All Sound Off on every MIDI channel.