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OnPoint is a follow-spot position tracking tool for live entertainment. An NDI camera mounted above front-of-house streams a bird's-eye view of the stage. Operators click on the video to send performer positions as PosiStageNet (PSN v2) UDP to a grandMA3 console. Multiple operators run simultaneously, each owning one or more tracker IDs (keys 1–9), and see all other operators' positions overlaid on the video.

Download

Pre-built installers for macOS (DMG) and Windows (EXE) are on the Releases page.

Quick start

1. Launch OnPoint and select an NDI source from the stream picker.
2. Open Setup → Calibration… and click at least four known stage marks, entering their real-world X/Z coordinates (metres). Click Compute Homography.
3. Open Setup → Settings… → Network to configure the PSN multicast address and port (defaults: 236.10.10.10:56565).
4. Press keys 1–9 to select a tracker, then click and hold on the video to send its position.

Keyboard & mouse

Action	Description
Keys 1–9	Select active tracker
Left click + hold	Aim selected tracker at stage position
Escape	Deselect all trackers

PSN network settings

Setting	Default	Description
Mode	Multicast	Multicast, Unicast, or Broadcast
Multicast IP	236.10.10.10	Standard PSN multicast address
Port	56565	Standard PSN port

Packets are sent at 60 Hz (data) and 1 Hz (info/name). Ensure IGMP snooping is configured on the switch, or enable multicast flooding.

Project files

Projects are saved as .onpoint JSON files (File → Save Project) and store calibration, tracker configuration, NDI source, and network settings.

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Development

Requirements

macOS

Dependency	Version	Install
macOS	13+	—
Xcode Command Line Tools	any	xcode-select --install
CMake	≥ 3.25	brew install cmake
Qt 6	≥ 6.4	brew install qt
OpenCV	≥ 4	brew install opencv
NDI SDK for Apple	6.x	ndi.video → macOS
Blackmagic DeckLink SDK	16.x	blackmagicdesign.com — headers bundled in third_party/

Windows

Dependency	Version	Install
Windows	10 / 11	—
Visual Studio Build Tools	2022	winget install Microsoft.VisualStudio.2022.BuildTools
CMake	≥ 3.25	winget install Kitware.CMake
Qt 6	6.8.3	pip install aqtinstall then python -m aqt install-qt windows desktop 6.8.3 win64_msvc2022_64 -m qtmultimedia --outputdir C:\Qt
OpenCV	≥ 4	via vcpkg: vcpkg install opencv:x64-windows
NDI SDK for Windows	6.x	ndi.video → Windows
Blackmagic DeckLink SDK	16.x	headers in third_party/decklink/Win/include/
Apple Bonjour SDK	any	developer.apple.com

Build

macOS

brew install cmake qt opencv
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --parallel
open build/onpoint.app

Tip: pass -DCMAKE_PREFIX_PATH=/opt/homebrew if Qt or OpenCV are not found.

Windows (PowerShell)

cmake -S . -B build -A x64 -DCMAKE_BUILD_TYPE=Release `
  "-DCMAKE_PREFIX_PATH=C:\Qt\6.8.3\msvc2022_64;C:\vcpkg\installed\x64-windows" `
  -DCMAKE_TOOLCHAIN_FILE="C:\vcpkg\scripts\buildsystems\vcpkg.cmake"
cmake --build build --config Release --parallel
C:\Qt\6.8.3\msvc2022_64\bin\windeployqt.exe build\Release\onpoint.exe

Windows installer

makensis /DVERSION=x.y.z packaging\windows.nsi