UNX DJ Engine

UNX DJ Engine is a specialized, high-performance DJ media player firmware subset. Developed in C and C++, it leverages the Raylib framework to provide a robust environment for cross-platform simulation, embedded development, and professional-grade audio processing. The project is engineered to replicate industry-standard hardware workflows while maintaining low-latency execution and high-fidelity signal processing.

Core Architecture

Audio Processing Engine

• Engine Core: Fully ported Mixxx Audio Engine (subset) for industry-standard reliability.
• Internal Pipeline: 32-bit floating-point internal mixing and DSP for maximum dynamic range and headroom.
• Memory Optimization: High-efficiency 16-bit PCM audio buffering, reducing RAM footprint by 50% for long-duration tracks.
• Decoding Engine: Native support for MP3 (minimp3), WAV, and AIFF (dr_wav) formats.
• Time-Stretching: High-fidelity Master Tempo and pitch-shifting utilizing Rubber Band and SoundTouch algorithms.
• Signal Processing: Professional 3-Band Isolator EQs (Fidlib), Biquad Filters, and an integrated FX pipeline (Sound Color FX and BPM-synced Beat FX).
• Synchronization: Precise lock-free parameter synchronization and automatic mono-to-stereo upmixing.

User Interface and Rendering

• Graphics Engine: Low-latency rendering via Raylib and OpenGL/GLES.
• Visualization: Optimized multi-mode waveform rendering with "Range-Vision" culling and Peak Binning (LOD) for flicker-free performance.
• Responsive Design: Adaptive layout engine supporting varying resolutions and High-DPI hardware configurations.
• PAD View: Integrated Performance Pads (4x2 grid) for instant Hot-Cue triggering and deck interaction.
• Hardware Accuracy: Precise emulation of industry-standard deck strips, top bars, and control panels.

Database and Library Management

• Rekordbox Integration: Full parsing of PDB and ANLZ database structures for metadata and waveform data.
• Serato Compatibility: Support for Serato metadata and waveform parsing logic.
• Storage Management: Efficient scanning and indexing for USB, SD, and internal storage devices.

Project Structure

├── assets/             # UI Assets (Fonts, Icons, Splash)
├── controllers/        # MIDI/HID Controller mappings
├── lib/                # Third-party libraries (Raylib, RubberBand, SoundTouch, etc.)
├── screenshots/        # Application UI screenshots
├── src/
│   ├── core/           # Audio backend (miniaudio), Logger, Logic (Sync/Quantize)
│   ├── engine/         # Ported Mixxx Audio Engine (Mixers, Buffers, FX, Sync)
│   ├── library/        # Database Readers (Rekordbox PDB/ANLZ, Serato)
│   ├── ui/
│   │   ├── browser/    # Library navigation and search UI
│   │   ├── components/ # Reusable UI widgets and Theme system
│   │   ├── player/     # Deck UI, Waveform rendering, DeckStrip
│   │   └── views/      # Main application views (Info, Settings, Mixer, About)
│   ├── main.c          # Application entry point and main loop
│   └── version.h       # Build metadata and versioning
└── tools/              # Build utilities and asset generators

Technical Specifications

Component	Technology
Language	C / C++ (C17 / C++17)
Graphics API	OpenGL 3.3 / GLES 2.0 / GLES 3.0
Framework	Raylib
Compiler	Zig Toolchain
Audio I/O	miniaudio
Audio Engine	Ported Mixxx Core (v2.4+)
Time-Stretching	Rubber Band / SoundTouch
EQ/Filters	Fidlib
FFT/DSP	QM-DSP

Deployment Platforms

• Windows (x86_64): Primary environment for development, simulation, and testing.
• Linux (ARM64/x64): Support for multiple graphics backends:
  • DRM-KMS: Optimized for embedded/firmware targets without a window manager.
  • Wayland: Modern desktop Linux support (e.g., Phosh on postmarketOS).
  • X11: Legacy desktop Linux compatibility.
• Android (ARM64): Mobile-optimized builds with NDK integration.
• iOS (ARM64): Native UIKit/CAEAGLLayer integration for high-performance mobile execution.

Tested Devices

Device	Status	Note
Armbian S905X Board	✅ Working
Windows 10 (HP Probook X360)	✅ Working	Primary Dev Environment
Xiaomi Redmi Note 3 Kenzo (Snapdragon)	✅ Working
Xiaomi Redmi Note 13	✅ Working
Xiaomi Redmi Note 3 Hennessy (Mediatek)	❌ Not Working	Stuck / Blank Screen
iPhone 8 Plus	❌ Not Working	Stuck / Blank Screen & Force Close

Important

If you encounter bugs or issues on a specific device, please let us know the device model and the nature of the bug by opening an issue. Your feedback helps us improve compatibility across more hardware.

Project Roadmap

• Core Mixer: Implementation of 3-band ISO EQs, Filters, and basic FX pipeline.
• Metadata Engine: Integration of Rekordbox PDB/ANLZ database parsing.
• Cross-platform UI: Unified rendering across desktop, embedded, and mobile platforms.
• Master Tempo: High-fidelity time-stretching via Rubber Band/SoundTouch.
• Performance Pads: Native PAD view for hot-cue and deck control integration.
• [/] MIDI/HID Control: Low-latency hardware mapping integration in progress.
• [/] Advanced FX: Expansion of the Beat FX and Sound Color FX libraries.

Build and Installation

The project utilizes the Zig toolchain for seamless cross-compilation and dependency management. Ensure the ZIG environment variable points to your zig.exe.

Windows Environment

Execute the provided batch script to build for Windows:

./build.bat windows

Linux (Cross-Compilation from Windows)

Build for specific graphics backends using the batch script:

# For Embedded Firmware (DRM-KMS)
./build.bat linux drm

# For Desktop/Wayland/X11
./build.bat linux desktop

Linux (Native Build)

Utilize the included build.sh script:

# Default (DRM)
./build.sh drm

# Desktop (Wayland/X11)
./build.sh desktop

Android and iOS

Mobile builds are managed via GitHub Actions CI/CD pipelines.

Keyboard Shortcuts

Note

Keyboard shortcuts are currently hardcoded and cannot be customized in the current version.

Key	Action
Z	Play / Pause (Deck 1)
A	Cue (Deck 1)
1 - 5	Hot Cues A - E (Deck 1)
Q	Sync / Beat Sync (Deck 1)
F	Beat FX Toggle (Deck 1)
N	Play / Pause (Deck 2)
H	Cue (Deck 2)
6 - 0	Hot Cues A - E (Deck 2)
Y	Sync / Beat Sync (Deck 2)
J	Beat FX Toggle (Deck 2)
SPACE	Toggle Browser View
I	Toggle Track Info View
TAB	Toggle Settings View
M	Toggle Mixer View
ESC	Back / Exit View

Credits and Acknowledgments

UNX DJ Engine is developed within the UNX DJ project ecosystem. It leverages a significant portion of the Mixxx open-source engine, adapted for embedded and low-latency environments.

• Mixxx Development Team: Core audio engine architecture, DSP logic, and signal processing.
• Rubber Band / SoundTouch: High-quality time-stretching and pitch-shifting algorithms.
• Raylib, minimp3, dr_libs: Core framework and media decoding libraries.

Contact and Social Media

• GitHub: github.com/rayocta303
• YouTube: @unxchr
• Instagram: @unxchr

Support and Development

For those interested in supporting the continued development of this project:

• PayPal: paypal.me/unxchr
• Saweria: saweria.co/patradev