Reaper LTC Markers

Scan a selected LTC / SMPTE media item inside REAPER, match codes from a CSV mapping, and insert project markers — no separate desktop app, no marker CSV import step.

Cross-platform ReaScript workflow (Windows + macOS). Same mapping format as REAtcMARK.

Features

• Select an LTC/SMPTE media item (or auto-suggest a track named SMPTE/LTC)
• CSV mapping: SMPTE Code,Marker Name (built-in gfx editor, or edit in Excel / Google Docs)
• Auto gain (default) + manual boost for quiet timecode stripes
• Replace or Append markers
• Live progress UI with a running list of found markers
• Report written next to the project: {ProjectName}_Markers_Report.txt

Architecture

Layer	What	Cross-platform?
UI, settings, CSV editor, markers	REAPER Lua (gfx, Actions) — no ReaImGui / ReaPack	Yes
LTC decode	Small native CLI ltc_scan (libltc)	One binary per OS

Lua scripts are identical on every machine. Only native/bin/ltc_scan (macOS) / ltc_scan.exe (Windows) differs. Download both from GitHub Actions → Artifacts after a build.

Quick install

Works the same on Windows and Mac: drop the folder in Scripts, load the action.

1. Get the Reaper-LTC-Markers folder (USB copy, clone, or download).
2. Ensure the helper for your OS is in native/bin/ (CI artifacts):
   • Windows: ltc_scan.exe
   • macOS: ltc_scan (universal Intel + Apple Silicon; script auto-sets executable — see INSTALL.md)
3. Copy the whole folder into your REAPER Scripts directory.
4. In REAPER: Actions → Show action list → Load ReaScript…
   → scripts/Reaper LTC Markers - Process.lua

Full steps (including Mac Terminal chmod +x and Gatekeeper): INSTALL.md

Workflow

1. Save the REAPER project.
2. Select the LTC item (or name the track SMPTE / LTC).
3. Run Reaper LTC Markers - Process.
4. Choose mapping CSV, FPS, gain, replace/append.
5. Watch the progress window; markers appear when the scan finishes.

CSV format

SMPTE Code,Marker Name
01:00:00:00,Song One
01:04:00:00,Song Two

Template: templates/smpte_mapping_template.csv

Native helper binaries (CI)

This repo includes a GitHub Action that builds Windows + macOS helpers without a local Mac.

1. Open the repo on GitHub → Actions → Build native helpers
2. Run workflow (Run workflow), or push a change under native/
3. Download artifacts:
   • ltc_scan-windows → place as native/bin/ltc_scan.exe
   • ltc_scan-macos → place as native/bin/ltc_scan and/or native/bin/macos/ltc_scan

On macOS, make it executable once (chmod +x) and approve Gatekeeper if prompted — step-by-step in INSTALL.md.

Local build (optional)

git submodule update --init --recursive
# Windows (MSYS2 gcc):
native/build_win.bat
# macOS:
native/build_mac.sh

libltc is included as a git submodule (libltc/ → x42/libltc).

Developer layout

Reaper-LTC-Markers/
  scripts/                 # ReaScripts + Lua modules
  native/                  # ltc_scan C sources + build scripts
  libltc/                  # submodule
  templates/               # CSV template
  .github/workflows/       # CI builds

License / credits

• Script project: use and adapt for your sessions.
• LTC decode: libltc (see that project for its license).