ETC PRS Viewer & Editor (Web-Based)

A modern, web-based viewer and editor for ETC Expression .prs personality files. This tool allows you to inspect, modify, and export fixture personalities using an intuitive UI with support for 16-bit channel pairing, drag-and-drop reordering, and local file history.

🚀 Application Functionality

Core Features

• Open & View PRS Files
  • Load .prs files directly from your system
  • Clean visual layout with card or table views
  • Accurate parsing based on reverse-engineered binary structure
• Edit Personalities
  • Modify channel attributes, flags, and home values
  • Support for:
    • Independent
    • LTP
    • 16-bit
    • Flipped
  • 16-bit channels are represented as a single unified card
• 16-bit Channel Handling
  • Proper pairing based on actual binary flags (no heuristics)
  • Editing applies correctly across paired channels
  • Home/display values follow ETC’s storage behavior (stored in second channel)
• Drag-and-Drop Reordering
  • Reorder channels using a dedicated drag handle
  • 16-bit pairs move together as a single unit
  • Prevents accidental dragging while editing inputs
• Export PRS Files
  • Export valid .prs files from both:
    • Viewer page
    • Editor page
  • Output matches ETC Personality Editor structure

UI Features

• Global Menu Bar
  • Open PRS File (auto-load on selection)
  • Create New PRS File
  • Previously Opened Files
  • Snapshot Versions
• Secondary Control Bar (Contextual)
  • Viewer:
    • Switch to Editor
    • Toggle Card/Table view
    • Export PRS
  • Editor:
    • Add Channel
    • Save Snapshot
    • Export PRS
    • Exit Editor
    • Toggle Card/Table view
• View Modes
  • Card-based layout for intuitive editing
  • Table view for compact overview

Data Persistence

Uses browser localStorage for: Recently opened files

• Snapshot history
• No backend required

🛠️ How to Run the Program

Requirements:

• Node.js (v18+ recommended)
• npm

Setup

Install dependencies

npm install

Run Development Server

npm run dev

Then open your browser to: http://localhost:5173

Build for Production

npm run build
npm run preview

⚠️ Ethical Disclosure

This project includes the use of AI-assisted development and reverse engineering techniques.

AI Usage

Portions of this application—including:

• UI implementation
• Data handling logic
• Iterative refinement of features

were developed with the assistance of an AI system (ChatGPT). All outputs were reviewed, tested, and refined by a human developer before inclusion.

Reverse Engineering

The .prs file format used by ETC Expression lighting consoles is not publicly documented in full detail. To support this application:

• The file format was analyzed through:
  • Inspection of real .prs files
  • Behavioral comparison with ETC’s Personality Editor
  • Static analysis of the Personality Editor executable
• No proprietary source code was accessed or used.
• The reverse engineering was limited to understanding file structure for interoperability.

Intent

This project is intended for:

• Educational purposes
• Interoperability and tooling
• Supporting legacy systems

It is not affiliated with or endorsed by ETC (Electronic Theatre Controls).

📌 Notes

• All file handling is local to your machine/browser
• No data is transmitted externally
• The application is designed to faithfully replicate ETC behavior where possible