LTC to MIDI Program Change

A Windows and macOS desktop application that reads SMPTE LTC (Linear Timecode) from an audio input and fires MIDI Program Change messages at defined timecodes — ideal for automating snapshots on a Waves LV1 mixing desk (or any MIDI-controllable system) during live shows.

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Features

• Windows and macOS — single codebase, native feel on both platforms
• Reads LTC from any audio input (ASIO, WDM, MME on Windows — CoreAudio on macOS)
• ASIO support — works with SoundGrid Driver and other ASIO interfaces
• ASIO channel names — channel dropdown shows the real driver names (e.g. "SoundGrid 1")
• Built-in virtual MIDI port on macOS — appears as a MIDI input in any app, no extra software needed
• Software BMC/LTC decoder — no external libraries needed
• Fires MIDI Program Change on any channel (1–16) at frame-accurate timecodes
• Supports 24, 25, 29.97, 30, 50, 59.94 and 60 fps
• Drop-frame timecode support
• Cue list saved as JSON — easy to edit and share
• TAP button to capture live timecode into a cue
• Test Fire button to verify MIDI output without waiting for the timecode
• Enable/Disable individual cues without deleting them
• Frame tolerance setting for real-world jitter

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Download

Go to the Releases page and download the file for your platform:

Platform	File
Windows	LTCtoMIDI.exe — no installation required
macOS	LTCtoMIDI.dmg — open and drag to Applications

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First Launch — Security Warnings

The app is not yet signed with a commercial certificate. Both Windows and macOS will warn you the first time you run it.

macOS

macOS Gatekeeper blocks apps from unidentified developers by default.

1. Try to open the app — Gatekeeper will block it
2. Open System Settings → Privacy & Security
3. Scroll down to the security section — you will see a message about LTCtoMIDI being blocked
4. Click Open Anyway
5. Confirm by clicking Open in the dialog that appears

After the first authorisation the app opens normally every time.

Windows

Windows may block the exe depending on your security settings.

Option A — Unblock in Properties (works on most systems):

1. Right-click LTCtoMIDI.exe → Properties
2. At the bottom, tick Unblock → click OK
3. Run the exe normally

Option B — SmartScreen warning (click More info → Run anyway): If a blue SmartScreen dialog appears when launching, click More info then Run anyway.

Option C — Windows 11 Smart App Control (most restrictive): Smart App Control does not have a "Run anyway" option. To run unsigned apps you need to disable it:

1. Open Windows Security → App & browser control
2. Click Smart App Control settings
3. Set it to Off

⚠️ Smart App Control cannot be re-enabled without reinstalling Windows.

🔐 A code signing certificate application has been submitted to SignPath.io under their open-source programme. Once approved, future releases will be signed and will not trigger any security warnings on Windows or macOS.

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Recommended Setup

macOS — Built-in Virtual MIDI Port

On macOS, LTC to MIDI creates its own virtual MIDI port automatically. No extra software needed.

1. Open LTC to MIDI
2. In the MIDI Output dropdown, select LTC to MIDI (virtual)
3. In your target software (DAW, Waves LV1, etc.), set the MIDI input to LTC to MIDI

That's it — no IAC Driver configuration required.

Windows — loopMIDI

On Windows, a virtual MIDI loopback driver is needed to route MIDI between apps on the same machine.

We recommend loopMIDI by Tobias Erichsen — free and widely used in professional audio.

1. Download loopMIDI: https://www.tobias-erichsen.de/software/loopmidi.html
2. Install and open loopMIDI
3. Click + to create a new virtual port (e.g. LTC-MIDI)
4. In LTC to MIDI, select that port as the MIDI Output
5. In your target software (Waves LV1, DAW, etc.), set the MIDI input to the same port

loopMIDI must be running before you start LTC to MIDI.

Physical MIDI Interface

On either platform, connect a USB MIDI interface and select it directly as the MIDI Output — no virtual port needed.

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Workflow

Audio source (playback / timecode track)
        │
        │  LTC audio signal
        ▼
  Sound card / ASIO interface
        │
        │  audio input
        ▼
  LTC to MIDI (this app)
        │
        ├─── macOS: LTC to MIDI (virtual) ──►  Waves LV1 / DAW / any CoreMIDI app
        │
        └─── Windows: loopMIDI port        ──►  Waves LV1 / DAW / any MIDI app

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Quick Start

1. Connect your LTC source to an audio input on your interface
2. Open LTC to MIDI
3. Select the Audio Input device and the channel carrying the LTC signal
4. Select the MIDI Output port:
   • macOS → select LTC to MIDI (virtual) — no extra setup needed
   • Windows → select your loopMIDI port or physical MIDI interface
5. Click ▶ START
6. The timecode display turns bright green when LTC is detected
7. Add cues to the list — set the timecode, MIDI channel, and Program Change number
8. Press Play on your timeline — cues fire automatically

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Cue List

Column	Description
#	Cue order number
Timecode	HH:MM:SS:FF — when to fire
Label	Free text description
PC	Program Change number (0–127)
Ch	MIDI channel (1–16)
✓	Enabled (● active / ○ disabled). Click to toggle

• Cues fire once per playback pass. They reset automatically when TC jumps backwards by more than 1 second.
• Use ↺ Reset to manually reset all fired flags (e.g. before a new run-through).
• Use ▶ Test to send a Program Change immediately without waiting for the timecode.
• Cue lists are saved as .json files — open them with any text editor.

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ASIO / SoundGrid

For SoundGrid Driver or any other ASIO interface:

• The SoundGrid Driver Control Panel must be running before you open the app (ASIO drivers register dynamically)
• Select the ASIO device from the Audio Input dropdown
• If the device does not appear, click ↺ to refresh the list

High frame rate (50 / 59.94 / 60 fps)

50 and 60 fps LTC uses a doubled bit rate — the signal runs at twice the speed of 25/30 fps LTC, while frame numbers still encode the base-rate count (0–24 or 0–29).

Use 96 kHz sample rate for reliable decoding at 50 fps and above. At 48 kHz the half-bit period drops to ~6 samples, which leaves very little margin for jitter. Select 96000 in the SR dropdown before starting.

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Frame Tolerance

The Frame tolerance ± setting (bottom of the window) defines how many frames early or late a cue can fire relative to its timecode. The default is ±1 frame. Increase it slightly if cues are occasionally missed due to jitter in your playback system.

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Building from Source

Requirements: Python 3.12+ and the packages in requirements.txt.

pip install -r requirements.txt
python main.py

To build the standalone .exe:

build.bat

Output: dist\LTCtoMIDI.exe

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License

MIT — free to use, modify and distribute.