Boomie

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| )___) )| (___) || (___) || )   ( |___) (___| (____/\
|/ \___/ (_______)(_______)|/     \|\_______/(_______/

  Made for Liefde.

Real-time music synth and composition engine written in Rust with support for custom file formats, dynamic playback control, and advanced audio effects. Ideal for real time playback.

Features

Audio Synthesis

• Waveform types: Sine, Square, Triangle, Sawtooth, and Noise
• Sample-based playback: Load and play WAV files with pitch adjustment
• ADSR envelope shaping: Full Attack, Decay, Sustain, Release control
• Real-time synthesis: Low-latency audio output using cpal

Effects Processing

• Reverb: Freeverb-based algorithm with room size, damping, wet/dry mix, and width controls
• Delay: Configurable delay time, feedback, and wet/dry mix
• Distortion: Drive, tone control, and wet/dry mix

File Formats

.mel, Melody Files

Define individual tracks with notes, instruments, and effects:

name: melody
waveform: sine
tempo: 120
volume: 0.8
attack: 0.01
decay: 0.1
sustain: 0.7
release: 0.2

note: C4, 1.0, 0.8
note: E4, 0.5, 0.9
note: G4, 1.0, 0.7

reverb: 0.6, 0.5, 0.3, 1.0

.bmi, Arrangement Files (Bundled Music Index)

Compose multiple melody tracks into complete songs:

name: song
track: bass.mel, 0.0
track: melody.mel, 2.0, volume=0.9
track: drums.mel, 4.0, pitch=1.2
loop: 0.0, 16.0

Compilation & Usage

Add to your Cargo.toml Dependecies:

# or newer when available
cpal = "0.16.0" 
fastrand = "2.3.0"
hound = "3.5.1"

Example

mod boomie;
use boomie::*;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut engine = SynthEngine::new()?;
    
    // Load a sample
    engine.load_sample("kick", "samples/kick.wav")?;
    
    // Load melodies
    engine.load_melody("bass", "melodies/bass.mel")?;
    engine.load_melody("lead", "melodies/lead.mel")?;
    
    // Load and play an arrangement
    let arrangement = engine.load_arrangement("songs/main.bmi")?;
    engine.play_arrangement(arrangement)?;
    
    // Enable looping
    engine.set_loop_enabled(true);
    
    // Dynamic control
    engine.set_master_volume(0.8);
    engine.set_track_volume("bass", 1.2);
    
    engine.stop();
    Ok(())
}

API Reference

Core Functions

• SynthEngine::new(): Create a new synthesizer engine
• load_sample(name, path): Load a .wav file into the sample cache
• load_melody(name, path): Load a .mel file
• load_arrangement(path): Load a .bmi file
• play_arrangement(arrangement): Start playback
• stop(): Stop playback and clean up

Playback Control

• pause() V resume(): Pause and resume playback
• set_loop_enabled(bool): Enable/disable looping
• crossfade_to(arrangement, duration): Smooth transition to a new arrangement
• get_playback_position(): Get current playback time
• get_playback_state(): Get current state (Playing/Paused/Stopped)

Dynamic Parameters

• set_master_volume(volume): Set global volume (0.0-2.0)
• set_master_pitch(pitch): Set global pitch multiplier (0.5-2.0)
• set_track_enabled(name, enabled): Enable/disable a track
• set_track_volume(name, volume): Set track volume (0.0-2.0)
• interpolate_track_volume(name, target, duration): Gradual volume change

File Format Reference

Melody File (.mel)

Metadata:

• name: - Melody name
• tempo: - BPM (default: 120)
• loop: - Loop points in seconds, start, end

Instrument:

• waveform: - sine | square | triangle | sawtooth | noise
• sample: - Reference to loaded sample name
• volume: - Amplitude (0.0-1.0)
• pitch: - Pitch multiplier
• attack:, decay:, sustain:, release: - ADSR envelope

Notes:

• note: PITCH, DURATION, VELOCITY
• Pitch: C4, D#5, Gb3, etc.
• Duration: In beats
• Velocity: 0.0-1.0

Effects:

• reverb: room_size, damping, wet, width
• delay: time, feedback, wet
• distortion: drive, tone, wet

Arrangement File (.bmi)

Metadata:

• name: - Arrangement name
• loop: - Loop points: start, end

Tracks:

• track: melody_file.mel, start_time, [overrides...]

Override parameters:

• volume=0.8 or vol=0.8
• pitch=1.2
• tempo=140
• reverb=0.6:0.5:0.3:1.0
• delay=0.25:0.4:0.3
• distortion=2.0:0.7:0.5 or dist=...

Note Parsing

Notes follow standard music notation:

• Base notes: C, D, E, F, G, A, B
• Sharps: C#, D#, etc. (also accepts 'S')
• Flats: Db, Eb, etc. (also accepts 'F' or 'B')
• Octaves: C4 (middle C), A3, E5, etc.

Technical Details

• Built on cpal for consistent audio output
• Freeverb algorithm for reverb effect
• Linear interpolation for sample playback
• Automatic gain normalization to prevent clipping