OpenTheFunk - An Open Source Audio Quality Analysis Tool

OpenTheFunk is a desktop application for analyzing the true quality of digital audio files. Using spectral analysis techniques, it can attempt to detect whether MP3 files are genuinely encoded at their declared bitrate or if they were upscaled from lower-quality sources.

Features

Audio Quality Detection

• MP3 Analysis: Detects genuine 320kbps files vs. upscaled 128k/192k/256k content
• Advanced Algorithms: Uses multiple spectral analysis methods including:
  • Cutoff frequency analysis
  • Spectral flatness measurement
  • Noise floor detection
  • Harmonic content analysis
  • Frame-to-frame variance analysis

Visual Analysis

• Spectrogram Viewer: Interactive spectrogram visualization with detailed frequency analysis
• Spectral Features: Displays cutoff frequencies, sharpness measurements, and spectral characteristics
• Evidence Breakdown: Shows detailed reasoning for each quality assessment

Performance & Usability

• Fast Scanning: Multi-threaded analysis with configurable worker count
• Smart Caching: .funk cache files speed up rescans of unchanged folders
• File Association: Double-click .funk files to open cached results for an album/folder
• Export Options: Export results to JSON, CSV, or text formats
• Cross-Platform: Works on Windows, macOS, and Linux

Results Management

• Comprehensive Reports: Detailed statistics and quality breakdowns
• Filtering & Sorting: Filter results by quality verdict and sort by various criteria
• Batch Processing: Scan entire music libraries with recursive folder support

Supported Formats

• .mp3 files
• .flac (limited testing)

Installation

Download (Coming Soon...)

Download the latest release from the releases page.

Windows File Association (Recommended)

The app should prompt you on first run if you would like to add a the .funk file association. In cases where you decline, this pop up does not appear, or you change your mind: please open a command prompt in the same folder as the OpenTheFunk.exe and run:

openthefunk.exe --register

if you prefer Powershell:

.\openthefunk.exe --register

This allows you to double-click .funk cache files to open them directly.

Usage

Basic Scanning

1. Launch OpenTheFunk
2. Click "File" → "Scan Folder" or use the toolbar button
3. Select a folder containing audio files
4. Wait for the analysis to complete
5. Review results in the table view

Understanding Results

The application provides several verdict categories:

• Likely genuine 320k: High-confidence genuine high-bitrate encoding
• Likely upscaled from ~128k/192k/256k: Files that appear higher quality but show spectral signs of lower-bitrate origin
• Likely genuine lossless: True lossless FLAC files
• Likely lossy-sourced FLAC: FLAC files transcoded from MP3 or other lossy formats
• Inconclusive: Cannot determine with confidence (may be genuinely ambiguous cases)

Spectrogram Analysis

• Select any file in the results table to view its spectrogram
• Right-click the spectrogram for additional options
• Use the collapse button to hide/show the spectrogram viewer

Cache System

• Results can be cached in .funk files within scanned folders (enable in settings)
• Cached results load instantly on subsequent scans of unchanged folders
• Cache validity is verified using folder content hashing. Changing anything in a folder will prompt a rescan.

Exporting Results

• Use "File" -> "Export Results" to save analysis data
• Choose from JSON, CSV, or text formats

Configuration

Access settings through "File" -> "Settings":

• Workers: Number of concurrent analysis threads (default: 4)
• Analysis Time: Maximum seconds to analyze per file (default: 30.0)
• Recursive Scanning: Include subdirectories (default: disabled)

Technical Details

Analysis Methods

The quality detection uses multiple complementary spectral analysis techniques:

1. Cutoff Frequency Analysis: Detects sharp frequency cutoffs indicative of lossy compression
2. Spectral Flatness: Measures noise-like content above cutoff frequencies
3. Noise Floor Analysis: Identifies abrupt transitions to noise floors
4. Harmonic Detection: Checks for harmonic content extending above cutoffs
5. Frame Variance: Analyzes consistency of high-frequency content across frames
6. Energy Ratios: Compares energy levels around cutoff frequencies

Accuracy

• High accuracy for detecting upscaled MP3s (90%+ confidence for clear cases)
• May produce inconclusive results for genuinely ambiguous cases
• Dark mastering or low high-frequency recording can cause false positives

Building from Source

Prerequisites

• Go 1.25.5 or later
• GCC (for CGO dependencies)

Build Steps

git clone https://github.com/spjoes/openthefunk.git
cd openthefunk
go mod download

then

go build -o openthefunk.exe ./cmd/openthefunk #Build without logs


go build -x -v -o openthefunk.exe ./cmd/openthefunk #Build with logs

Acknowledgments

This app is inspired by Fakin' The Funk

Support

For issues, questions, or feature requests:

1. Check existing issues
2. Create a new issue with detailed information
3. Include sample files if reporting analysis issues (ensure you have rights to share)

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Note: This tool is for informational purposes. Always verify important audio quality assessments through multiple methods and trusted sources. Although not required, it is recommended you analyze the spectrogram for each file manually.