ReaTC

Sync REAPER with your lighting console using Art-Net, MIDI Timecode, and OSC.

Utility for lighting programmers using REAPER

Installation

Via ReaPack (Recommended)

1. Install ReaPack if you haven't already
2. Extensions > ReaPack > Import repositories
3. Add this URL:

https://github.com/paskateknikko/ReaTC/raw/reapack/index.xml

4. Extensions > ReaPack > Browse packages → search "ReaTC" → Install
5. Restart REAPER — the C++ extension is only loaded at startup

Manual Installation

1. Download the latest ReaTC-x.x.x.zip from GitHub Releases
2. Extract the zip contents into your REAPER resource folder:
   • Windows: %APPDATA%\REAPER\
   • macOS: ~/Library/Application Support/REAPER/
   • The zip contains Scripts/, Effects/, and UserPlugins/ folders that merge with your existing REAPER resource folder
3. Restart REAPER — the C++ extension is only loaded at startup
4. In REAPER: Actions > Show action list > Load ReaScript > select Scripts/ReaTC/Timecode/reatc.lua

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Features

Timecode Sources

• LTC audio decoder — real-time biphase-mark decoding with adaptive clock recovery; auto-detects frame rate (24/25/29.97DF/30); configurable threshold; varispeed support
• MTC input — receives and decodes MIDI Timecode quarter-frame and full-frame SysEx messages; instant locate; 2-frame lag compensation
• REAPER Timeline — reads timecode directly from transport position
• Source priority system — each source configurable as High/Normal/Low priority with automatic failover

Timecode Outputs

• Art-Net TimeCode — broadcasts SMPTE TC over UDP (port 6454); unicast or broadcast; configurable IP
• MIDI Timecode (MTC) — sample-accurate quarter-frame generator via JSFX; no external MIDI library required
• OSC — broadcasts SMPTE TC as raw OSC (/tc ,iiiii H M S F type) at ~30 fps; configurable destination IP, port, and address
• LTC audio generator — encodes timecode to LTC audio with slew-rate shaping matching REAPER's native LTC waveform
• LTC User Bits — configurable user bits format (Characters/Date-Timezone) with SMPTE/EBU BGF flag positioning
• Bake LTC from regions — standalone tool generates offline LTC WAV files from project regions with per-region TC start, FPS, and output level

General

• TC Offset — user-configurable HH:MM:SS:FF offset applied before all outputs; supports drop-frame wrap-around
• LTC Diagnostics — dedicated analysis JSFX with waveform display, bit histogram, timing analysis, and auto-detected frame rate / BGF positioning
• Network sync status — Art-Net and OSC toggleable directly from the main window
• All standard frame rates — 24fps (Film), 25fps (EBU/PAL), 29.97fps Drop Frame, 30fps (SMPTE)
• Dark UI — unified dark style across Lua script and JSFX; scalable TC display
• Cross-platform — macOS (10.15+) and Windows (10+); Python 3 standard library only
• ReaPack compatible — install via package manager; ReaImGui auto-installed as dependency

Use Cases

• Playback sync — play a REAPER project and broadcast timecode to lighting consoles, video servers, or other devices via Art-Net, OSC, MTC, or LTC
• Timecode format conversion — convert between any supported formats without playback (e.g. MTC→LTC, LTC→Art-Net, MTC→OSC); all outputs run whenever valid TC is present, independent of REAPER's transport state
• Offline LTC rendering — bake LTC audio from project regions for pre-programmed shows or backup timecode tracks

Usage

Setup

ReaTC has two components:

1. ReaTC Timecode Converter (JSFX plugin) — handles all TC sources and outputs
2. ReaTC script (Lua) — provides the UI and sends Art-Net/OSC over the network

Step 1: Add the JSFX plugin

1. Select the track you want to use for timecode (or create a new one)
2. Open the FX browser (click the FX button on the track)
3. Search for "ReaTC Timecode Converter" and add it

The JSFX plugin handles:

• Sources: LTC audio input decoding, MTC MIDI input decoding, REAPER timeline
• Outputs: LTC audio encoding, MTC MIDI quarter-frame generation, gmem bridge to the Lua script

When collapsed, the plugin shows a compact timecode display:

When resized wider, the plugin shows a compact timecode display:

Click the ⚙ icon to access JSFX settings (framerate, LTC threshold, output level, user bits, BGF mode):

Step 2: Run the Lua script

1. Click the "Open ReaTC Script" button in the JSFX Network output section, or Actions menu > search "ReaTC" > run Art-Net and MIDI Timecode sender for REAPER
2. The script window shows the active timecode and output status
3. Click Settings to configure Art-Net and OSC destinations

Configuring TC Sources

In the JSFX plugin UI, enable the sources you need:

• LTC Input — route LTC audio to the track; the decoder locks onto the signal automatically
• MTC Input — route MIDI containing MTC messages to the track
• Timeline — uses REAPER's transport position (enabled by default)

Each source has a priority (High / Normal / Low). When multiple sources are locked, the highest-priority source wins. Ties are broken by: LTC > MTC > Timeline.

Configuring TC Outputs

In the JSFX plugin UI, enable the outputs you need:

• LTC Audio — generates LTC audio on the track's output; configure output level with the slider
• MTC MIDI — emits quarter-frame messages on the track's MIDI output; configure the MIDI output port via the track's I/O button
• Script — writes TC to shared memory (gmem) for the Lua script to read; required for Art-Net and OSC output

Art-Net TC Output

1. Run the ReaTC script and open Settings
2. Set the destination IP (e.g., 2.0.0.1 for Art-Net unicast, or 2.255.255.255 for broadcast)
3. Enable Art-Net Output — packets send whenever valid TC is present

OSC Timecode Output

1. Run the ReaTC script and open Settings
2. Set destination IP, port (default 9000), and OSC address (default /tc)
3. Enable OSC Output — broadcasts /tc ,iiiii H M S F type at ~30 fps

Bake LTC from Regions

1. Create regions in your REAPER project
2. Run the ReaTC script, open Settings, click Bake LTC from Regions...
3. Configure TC start and framerate per region, then render
4. Rendered WAV items are placed on a LTC [rendered] track

LTC User Bits

In the JSFX settings, set User Bits format (Characters or Date/Timezone) and enter 4 byte values (0–255). These are embedded in the LTC stream per SMPTE 12M. At 25fps, you can choose between SMPTE (REAPER-compatible) and EBU standard BGF bit positions.

LTC Diagnostics

Add the ReaTC LTC Diagnostics JSFX to the same track (or any track receiving LTC audio) to inspect the signal in detail. Auto-detects frame rate, BGF positioning, and decodes user bits.

Troubleshooting

"Python 3 not found"

• macOS: Python 3 is pre-installed on macOS 12.3+. For older versions, install from python.org.
• Windows: Install from the Microsoft Store (python3) or python.org. Make sure Python is added to your PATH. Restart REAPER after installing.

"JSFX not detected"

• Add the ReaTC Timecode Converter JSFX to any track (FX browser > search "ReaTC").
• Make sure the JSFX is enabled (not bypassed) and the track is not muted.

No Art-Net packets being received

• Check the destination IP matches your console's Art-Net interface.
• Verify your firewall allows outbound UDP on port 6454.
• For broadcast, use the subnet broadcast address (e.g., 2.255.255.255).

No OSC messages being received

• Verify the destination IP, port, and OSC address match the target application's settings.
• Check your firewall allows outbound UDP on the configured port.

LTC not decoding

• Route LTC audio to the track with the JSFX. Check the peak meter in the plugin UI.
• Adjust the LTC threshold slider if the signal is too quiet.

Requirements

• REAPER 6.32+ (required for gmem_attach() shared memory API)
• ReaImGui (auto-installed via ReaPack)
• Python 3 (pre-installed on macOS; Microsoft Store or python.org on Windows) No third-party Python packages required.

License

MIT — see LICENSE