Installation & CLI Usage

OpenBPM can be installed as a standalone CLI utility or integrated as a library dependency in your Rust projects.

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Installing the CLI

Via Cargo

cargo install open-bpm

From Source

git clone https://github.com/ASmallDuck/open-bpm
cd open-bpm
cargo build --release

The compiled binary will be available at ./target/release/open-bpm.

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CLI Usage

Basic Tempo Detection

Output only the detected BPM:

open-bpm track.mp3
# Output: 128.0

Detailed Diagnostics

Inspect individual estimator outputs and confidence scores:

open-bpm --verbose track.flac

Machine-Readable Output (JSON)

Generate JSON for scripts, automation, and audio pipelines:

open-bpm --format json track.wav

Sample JSON response:

{
  "bpm": 124.02,
  "confidence": 0.91,
  "grid_offset": 0.124,
  "stage1_bpm": 124.02,
  "router_action": "keep",
  "router_confidence": 0.88
}

Constraining the Search Range

For specialized genres (e.g. ambient or drum & bass), customize the search range:

open-bpm --min-bpm 80 --max-bpm 180 track.ogg

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Supported Audio Codecs

OpenBPM leverages Symphonia for native, pure Rust audio decoding:

• WAV (PCM 16/24/32-bit, float)
• MP3 (MPEG-1/2 Audio Layer III)
• FLAC (Free Lossless Audio Codec)
• OGG (Vorbis)
• AAC (Advanced Audio Coding)

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Using as a Rust Library

Add to your Cargo.toml:

[dependencies]
open-bpm = "0.1"

In your code:

use open_bpm::{detect, detect_with_options, DetectOptions};

fn main() {
    let samples: Vec<f32> = load_mono_samples();
    let sample_rate = 44100;

    // Standard detection
    let result = detect(&samples, sample_rate);
    println!("{:.1} BPM (confidence: {:.0}%)", result.bpm, result.confidence * 100.0);
    println!("First beat at {:.3}s", result.grid_offset);

    // Custom options
    let opts = DetectOptions {
        min_bpm: 80.0,
        max_bpm: 180.0,
        ..Default::default()
    };
    let custom_result = detect_with_options(&samples, sample_rate, &opts);
}