Leyline Virtual Audio Device (Rust)

A high-performance, native Rust WaveRT virtual audio driver for Windows. This implementation leverages the wdk-rs framework to provide a memory-safe alternative to traditional C++ kernel development.

Current Status

The core adapter logic is stable, and the driver registers with PortCls as expected. However, the Audio Endpoint Builder is currently not enumerating the endpoints. This is pretty weird as my C++ implementation initializes correctly in the same environment. Currently looking into this.

Project Layout

LeylineVirtualAudioDeviceRust/
├── crates/
│   ├── leyline-kernel/         # Kernel-mode driver (Rust, no_std, WDM)
│   └── leyline-shared/         # Common logic shared across kernel/user boundary
├── src/
│   ├── APO/                    # Audio Processing Object (C++, COM)
│   └── HSA/                    # Hardware Support App (C#, WinUI 3)
├── scripts/
│   ├── LaunchBuildEnv.ps1      # eWDK & Rust environment initializer
│   ├── Install.ps1             # Automated build, package, and install pipeline
│   └── Uninstall.ps1           # Driver removal and cleanup script
├── test/
│   └── EndpointTester/         # C# utility to verify audio endpoint enumeration
├── package/                    # Staged build artifacts (gitignored)
├── Makefile.toml               # cargo-make task definitions
└── README.md

Building & Deployment

Prerequisites

• eWDK (Enterprise WDK) at D:\eWDK_28000 or set LEYLINE_EWDK_ROOT.
• Windows 10 / 11 SDK 10.0.28000.0 or set LEYLINE_SDK_VERSION.
• Rust Toolchain 1.75+ (no_std) with cargo-make installed (cargo install cargo-make).
• A Hyper-V VM named LeylineTestVM (for automated deployment testing).

1. Initialize Environment

Before building, you must initialize the eWDK environment in your current PowerShell session:

.\scripts\LaunchBuildEnv.ps1

2. Building All Components

The project uses cargo-make to orchestrate the multi-language build (Rust, C++, C#).

Command	Description
cargo make build-all	Builds Kernel, APO, and HSA individually.
cargo make build	Builds and stages all components into the package/ folder.
cargo make clean	Purges all build artifacts and target directories.

3. Automated Deployment (VM)

To build, sign, and deploy the entire stack to a target Hyper-V VM:

# Full build and install to VM
cargo make install

# Clean build and install
.\scripts\Install.ps1 -clean

4. Individual Component Builds

If you need to work on a specific layer, you can use these targeted tasks:

cargo make build-kernel  # Rust Driver
cargo make build-apo     # C++ APO
cargo make build-hsa     # C# WinUI 3 App

Key Design Decisions

• Unified Build System: Uses cargo-make to bridge the gap between Rust's cargo, C++'s nmake, and C#'s dotnet.
• Automatic Staging: All successful builds are staged in the package/ folder and signed automatically for kernel-mode compatibility.
• Software Component Integration: The INF automatically registers the HSA as a Software Component, allowing for modern hardware-app associations.
• APO Multi-Effect Registration: Registers the Leyline APO for Stream, Mode, and Endpoint effects during installation.

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Last Updated: February 28, 2026