What each protocol does

LTCast outputs five protocols simultaneously from a single internal clock. You can enable any combination — each protocol targets a different class of receiving device, and they do not interfere with each other.

LTC — Linear Timecode

LTC is SMPTE timecode encoded as an audio signal. It travels on a standard audio cable to any device that has an audio input. Because it is audio, it works over analogue XLR, TRS, or digital S/PDIF connections without any special adapters.

• Frame-accurate position sync
• Accepted by audio consoles, video systems, lighting desks, and any device with a timecode audio input
• The most universally compatible format — if a device accepts timecode at all, it almost certainly accepts LTC
• LTCast can also decode incoming LTC (Chase mode) and re-broadcast it on all other protocols

MTC — MIDI Timecode

MTC is SMPTE timecode carried over MIDI. LTCast sends quarter-frame messages during continuous playback for smooth sync, and full-frame SysEx messages when jumping to a new position.

• Frame-accurate position sync
• Accepted by DAWs (Pro Tools, Logic, Ableton), lighting consoles (ETC Eos, grandMA series), and MIDI-enabled hardware
• Requires a physical MIDI cable or a virtual MIDI port (loopMIDI on Windows, IAC Driver on macOS)
• Quarter-frame messages: 4 messages per frame (the 8 pieces of a full timecode address span two frames), sent while the song plays
• Full-frame SysEx: a single message sent when playback starts, after you seek, and when you select the MIDI port. Set MTC Mode to Full-frame (legacy) in Settings → Outputs to send it on every frame instead

MIDI Clock

MIDI Clock is a tempo-based sync format. It transmits 24 pulses per quarter note (PPQ) with no absolute position information — only the current BPM. Receiving devices follow the tempo and beat division, but do not know the SMPTE timecode address.

• Tempo sync at 24 PPQ
• Accepted by synthesizers, drum machines, sequencers, and tempo-aware effects
• LTCast can auto-detect BPM from the audio file and use that as the MIDI Clock rate, or you can tap a tempo or type one in
• A Start message is sent when playback starts or resumes and a Stop message when it pauses or stops. There is no Continue message: pausing and pressing Play again sends Start again, so a device that follows Start will restart from the top of its pattern

Art-Net — OpTimeCode

Art-Net carries SMPTE timecode over standard UDP Ethernet on port 6454. No special cabling is required beyond a network switch or Wi-Fi access point. One LTCast instance can reach every device on the same network simultaneously.

• Frame-accurate position sync
• Accepted by lighting consoles (grandMA2, grandMA3, Hog 4, ChamSys MagicQ) and media servers
• Travels over standard Ethernet or Wi-Fi — no MIDI cable, no audio cable
• Configure a target IP or broadcast to the subnet (e.g., 2.255.255.255 for the Art-Net default subnet)

OSC — Open Sound Control

OSC sends timecode as UDP messages to the IP address and port you set. LTCast includes built-in templates for popular media server software.

• Frame-accurate position sync
• Built-in templates: Generic (/timecode), Resolume Arena, Disguise (d3) and WATCHOUT. Each template has a fixed address and format; there is no custom address
• Configurable target IP and port, with more than one target if you need it
• Besides timecode, LTCast also sends /transport/play, /transport/pause and /transport/stop and a /song message when a song is loaded
• Useful when a device accepts OSC but not Art-Net

Comparison