AudioSync

VST3 plugin written in C++ using the JUCE framework. It automatically synchronizes multiple 360-degree camera recordings by decoding SMPTE LTC (Linear Time Code) timecode from audio tracks, computing per-track delays, and applying them in real time. When LTC degrades or cuts out, an audio-based fallback (Normalized Cross-Correlation on novelty curves) takes over seamlessly.

Architecture

The plugin runs in two roles that must be configured in the DAW session:

• Master - placed on the reference LTC track. Decodes LTC, extracts an audio novelty curve, and writes both to shared memory. Does not delay its own output.
• Slave - one instance per additional track. Reads master data from shared memory, decodes its own LTC, computes the inter-track delay, and applies it via a delay engine. Up to 8 slave instances are supported per group.

Both roles share a group name (set in the plugin UI) which identifies the shared-memory region used for communication.

Installation

Navigate to the latest release and download a package compatible with your OS.

Extract the package into your DAW's VST3 scan directory. Typically ~/.vst3 for Linux, and C:\Common Files\VST3 on Windows.

Alternatively, you can build the plugin yourself, as per instructions below.

Building

Make sure the following are installed:

• JUCE - C++ framework for audio applications and plugins.
• CMake 3.22+ and a C++17 compiler (Linux/macOS build).
• Visual Studio 2022 (Windows build).
• Git - version control.

Clone the repository:

git clone https://github.com/filipleple/audiosync

Build (Linux / macOS)

mkdir -p build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DJUCE_PATH=../../juce-8.0.10-linux/JUCE
cmake --build . -j$(nproc)

Output: build/AudioSyncPlugin_artefacts/Release/VST3/

Build (Windows)

Open the repo directory in Power Shell and run:

cmake -S . -B build -G "Visual Studio 18 2026" -A x64 -DJUCE_PATH=C:\Users\vboxuser\Workspace\JUCE
cmake --build build --config Release

Replacing Visual Studio 18 2026 with your appropriate version, and -DJUCE_PATH pointing to the actual path to JUCE on your machine.

Usage

1. In your DAW, load the VST3 on the reference LTC track. Set its role to Master and choose a group name.
2. Load a second instance on each additional track. Set its role to Slave and use the same group name.
3. Press play. The master displays the decoded timecode (HH:MM:SS:FF). Each slave displays its computed delay in milliseconds and frames, and applies the delay automatically.
4. A manual correction slider is available on each instance for fine-tuning.
5. When LTC quality drops (Q_LTC < 0.5), the plugin transparently switches to audio-based delay tracking. The diagnostics card shows the active source (LTC / AUD / NONE).

Authors and Acknowledgements

• Dr. Bartłomiej Mróz - problem diagnosis and formulation, supervision and guidance
• Filip Lewinski - author
• Tsimafei Dalhou - initial work on LTC decoding and synchronization via delay