FireWire Audio Daemon

A modern C++ application (potentially evolving into a daemon) for interfacing with FireWire (IEEE 1394) audio devices on macOS, providing low-level device discovery, control, and configuration capabilities.

Overview

This project implements a FireWire audio device daemon that handles:

• Device discovery and hot-plugging
• AV/C (Audio/Video Control) command interface
• Music and Audio subunit control

Features

• Device Discovery: Automatic detection and monitoring of FireWire audio devices
• Command Interface: Implementation of AV/C command protocol

Plug Management (TODO)

• Isochronous input/output plugs
• External input/output plugs
• Music subunit plugs
• Audio subunit plugs
• Stream format discovery

Modern C++ Design

• RAII principles
• Smart pointers
• STL containers
• Error handling with std::expected
• Thread-safe operations

Requirements

• XCode 15 or later
• CMake 3.21 or later
• Modern C++ compiler with C++23 support

Dependencies

• spdlog (v1.13.0) - Modern C++ logging
• Catch2 (v3.5.2) - Testing framework
• IOKit framework
• CoreFoundation framework

Building

I recommend create a XCode project using cmake:

mkdir build && cd build
cmake -G Xcode ..
open FireWireAudioDaemon.xcodeproj

Architecture

The application is built around several key components:

Device Discovery (IOKitFireWireDeviceDiscovery)

• Handles device arrival/removal
• Manages device lifecycle
• Provides device enumeration

Device Controller (DeviceController)

• High-level device management
• Command routing
• State management

Command Interface (CommandInterface)

• AV/C command implementation
• Low-level device communication
• Error handling

Device Parser (DeviceParser) (TODO)

• Capability discovery
• Format parsing
• Plug configuration

Future plans

The primary goal is to restore FireWire audio functionality on modern macOS versions by implementing isochronous audio stream handling. Since Apple removed AppleFWAudio.kext from the latest versions of their operating systems, and older devices rely on a specific set of standards, restoring FireWire audio functionality is a feasible task. Currently, I am implementing device handling and planning to add isochronous stream support. I have successfully sent audio to and from a device as a proof of concept, but before advancing further, I need a proper tool to handle device controls effectively.

Contributing

Contributions are highly encouraged! If you're interested, please submit issues and pull requests to help improve and develop the project further.

Code Formatting

This project uses clang-format for consistent code formatting. A .clang-format file is provided in the root directory that defines the project's coding style.

Required Version

This project requires clang-format version 16.0.0 or later. A script is provided to install the correct version:

# Check if the correct version is installed
./tools/install-clang-format.sh --check-only

# Install the correct version if needed
./tools/install-clang-format.sh

The script will detect your operating system and install clang-format using the appropriate package manager (Homebrew for macOS, apt/dnf/pacman for Linux).

CMake Integration

The project includes CMake targets for code formatting:

# Format all source files
cmake --build build --target format

# Check if all source files are formatted correctly
cmake --build build --target format-check

# Install the required clang-format version
cmake --build build --target install-clang-format

These targets are available after configuring the project with CMake.

Editor Integration

VSCode

1. The project's .vscode/settings.json is already configured to use clang-format
2. Use the extension of your choice (c/c++ extension or clang-format extension) to format your code on save Xcode
3. Install ClangFormat-Xcode
4. Configure it to use the project's .clang-format file

Pre-commit Hook

A Git pre-commit hook is included that automatically formats your code before committing. The hook:

• Runs clang-format on all staged C/C++/Objective-C files
• Re-stages the formatted files
• Allows you to bypass the hook with git commit --no-verify if needed

To enable the hook, make sure it's executable:

chmod +x .git/hooks/pre-commit

License

This project is licensed under the MIT License.

SAST Tools

PVS-Studio - static analyzer for C, C++, C#, and Java code.

Acknowledgments

• Based on Apple's IOKit FireWire Family framework architecture
• Inspired by AVCVideoServices sample code (found in the FireWire SDK)