AudioFXRS - Rust Audio Effects Processor

The aim of this project is just explore audio effects and learn rust by building an audio effects CLI tool. A modular, command-line audio effects processor written in Rust. This project provides a unified interface for applying various audio effects to WAV files with configurable parameters.

Features

Implemented Effects

• Chorus: Adds richness by simulating multiple detuned versions of the input signal
• Delay/Echo: Creates echoes by delaying the input signal with configurable feedback and damping
• Distortion: Multiple distortion types including soft clip, hard clip, overdrive, and fuzz
• Gate/Noise Gate: Removes background noise by cutting off signals below a threshold
• Limiter: Prevents audio from exceeding a threshold with configurable attack/release times
• Reverb: Algorithmic reverb with configurable room size, damping, and pre-delay
• Compression: Dynamic range compression with configurable threshold, ratio, attack, and release
• EQ: 3-band equalizer with adjustable frequency bands and gains
• Flanger: Sweeping comb filter effect with modulated delay
• Phaser: Phase modulation effect creating moving notches in the frequency spectrum
• Tremolo: Amplitude modulation with multiple waveform shapes
• Vibrato: Pitch modulation effect
• Pitch Shifting: Change pitch without affecting duration (basic implementation)
• Time Stretching: Change duration without affecting pitch (basic implementation)

Architecture

The codebase has been completely refactored with a modular design:

• Unified CLI: Single binary with effect selection via command line
• Common Audio I/O: Shared WAV file reading/writing with proper error handling
• Effect Trait System: All effects implement a common AudioEffect trait
• Parameter System: Type-safe parameter handling with validation
• DSP Utilities: Shared digital signal processing functions and delay lines

Installation

git clone <repository-url>
cd audiofxrs
cargo build --release

Usage

Basic Syntax

audiofxrs <effect> <input.wav> <output.wav> [--param value]

List Available Effects

audiofxrs --list

Get Effect Information

audiofxrs --info <effect_name>

Examples

# Apply chorus with custom parameters
audiofxrs chorus input.wav output.wav --rate 2.0 --depth 3.0 --mix 0.7

# Apply delay/echo
audiofxrs delay input.wav output.wav --delay 500 --feedback 0.4 --mix 0.5

# Apply gate/noise gate
audiofxrs gate input.wav output.wav --threshold 0.1 --release 100 --ratio 1.0

# Apply limiter
audiofxrs limiter input.wav output.wav --threshold 0.8 --attack 1.0 --release 50

# Apply distortion
audiofxrs distortion input.wav output.wav --gain 3.0 --type 1 --mix 0.8

# Apply reverb
audiofxrs reverb input.wav output.wav --room_size 0.8 --mix 0.4 --damping 0.6

# Apply compression
audiofxrs compression input.wav output.wav --threshold 0.3 --ratio 4.0 --attack 5.0

# Apply tremolo with triangle wave
audiofxrs tremolo input.wav output.wav --rate 8.0 --depth 0.6 --wave 1

# Get help for a specific effect
audiofxrs --info chorus

Effect Parameters

Chorus

• --rate: LFO rate in Hz (0.1 to 10.0, default: 0.5)
• --depth: Modulation depth in milliseconds (0.1 to 10.0, default: 2.0)
• --mix: Wet/dry mix (0.0 to 1.0, default: 0.5)
• --feedback: Feedback amount (0.0 to 0.9, default: 0.0)

Delay

• --delay: Delay time in milliseconds (10.0 to 2000.0, default: 250.0)
• --feedback: Feedback amount (0.0 to 0.9, default: 0.3)
• --mix: Wet/dry mix (0.0 to 1.0, default: 0.3)
• --damping: High frequency damping of feedback (0.0 to 1.0, default: 0.2)

Gate

• --threshold: Gate threshold (0.001 to 1.0, default: 0.1)
• --attack: Attack time in milliseconds (0.1 to 100.0, default: 1.0)
• --hold: Hold time in milliseconds (0.0 to 1000.0, default: 10.0)
• --release: Release time in milliseconds (1.0 to 5000.0, default: 100.0)
• --ratio: Gate ratio - 1.0 = full gate, 0.0 = no gate (0.0 to 1.0, default: 1.0)

Limiter

• --threshold: Limiting threshold (0.1 to 1.0, default: 0.8)
• --attack: Attack time in milliseconds (0.1 to 10.0, default: 1.0)
• --release: Release time in milliseconds (1.0 to 500.0, default: 50.0)
• --output: Output gain (0.1 to 2.0, default: 1.0)

Distortion

• --gain: Input gain amount (0.1 to 10.0, default: 2.0)
• --threshold: Distortion threshold (0.1 to 1.0, default: 0.7)
• --mix: Wet/dry mix (0.0 to 1.0, default: 1.0)
• --output: Output level (0.1 to 1.0, default: 0.8)
• --type: Distortion type (0=Soft, 1=Hard, 2=Overdrive, 3=Fuzz, default: 0)

Reverb

• --room_size: Room size (0.1 to 1.0, default: 0.5)
• --damping: High frequency damping (0.0 to 1.0, default: 0.5)
• --mix: Wet/dry mix (0.0 to 1.0, default: 0.3)
• --feedback: Feedback amount (0.0 to 0.9, default: 0.5)
• --pre_delay: Pre-delay time in milliseconds (0.0 to 100.0, default: 20.0)

Compression

• --threshold: Compression threshold (0.0 to 1.0, default: 0.5)
• --ratio: Compression ratio (1.0 to 20.0, default: 4.0)
• --attack: Attack time in milliseconds (0.1 to 100.0, default: 10.0)
• --release: Release time in milliseconds (10.0 to 1000.0, default: 100.0)
• --makeup: Makeup gain (0.1 to 4.0, default: 1.0)

EQ

• --low_gain: Low frequency gain in dB (-12.0 to 12.0, default: 0.0)
• --mid_gain: Mid frequency gain in dB (-12.0 to 12.0, default: 0.0)
• --high_gain: High frequency gain in dB (-12.0 to 12.0, default: 0.0)
• --low_freq: Low/mid crossover frequency (100.0 to 1000.0, default: 300.0)
• --high_freq: Mid/high crossover frequency (1000.0 to 8000.0, default: 3000.0)

Tremolo

• --rate: Tremolo rate in Hz (0.1 to 20.0, default: 5.0)
• --depth: Modulation depth (0.0 to 1.0, default: 0.7)
• --wave: Wave shape (0=Sine, 1=Triangle, 2=Square, 3=Sawtooth, default: 0)

File Format Support

Currently supports:

• Input: 16-bit PCM WAV files
• Output: 16-bit PCM WAV files
• Sample Rates: 8 kHz to 192 kHz
• Channels: Mono and stereo (effect-dependent)

Development

Project Structure

src/
├── main.rs              # Entry point
├── cli.rs               # Command-line interface
├── audio_io.rs          # Audio file I/O utilities
└── effects/
    ├── mod.rs           # Effect trait and common utilities
    ├── chorus.rs        # Chorus effect implementation
    ├── delay.rs         # Delay/Echo effect implementation
    ├── distortion.rs    # Distortion effect implementation
    ├── gate.rs          # Gate/Noise Gate effect implementation
    ├── limiter.rs       # Limiter effect implementation
    ├── reverb.rs        # Reverb effect implementation
    ├── compression.rs   # Compression effect implementation
    ├── eq.rs           # EQ effect implementation
    ├── flanger.rs      # Flanger effect implementation
    ├── phaser.rs       # Phaser effect implementation
    ├── tremolo.rs      # Tremolo effect implementation
    ├── vibrato.rs      # Vibrato effect implementation
    ├── pitch_shifting.rs # Pitch shifting effect (basic)
    └── time_stretching.rs # Time stretching effect (basic)

Adding New Effects

1. Create a new module in src/effects/
2. Implement the AudioEffect trait
3. Register the effect in src/cli.rs
4. Add tests following the existing patterns

Running Tests

cargo test

Building for Release

cargo build --release

Future Improvements

• Additional Effects: Expansion, frequency shifting, ring modulation, bitcrushing
• Better Algorithms: Improved pitch shifting and time stretching using PSOLA or phase vocoder
• Multi-channel Support: Full surround sound processing
• Real-time Processing: Live audio processing capabilities
• Plugin Format: VST/AU plugin versions
• GUI Interface: Graphical user interface for parameter control

Dependencies

• hound: WAV file I/O
• dasp: Digital audio signal processing utilities
• biquad: Digital filter implementations

License

GNU General Public License v3.0 - see LICENSE file for details.