Realtime BPM Analyzer

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Library Privacy ​

Overview ​

This page covers the realtime-bpm-analyzer library itself. It is designed with privacy as a core principle. All audio processing happens entirely in your browser using the Web Audio API.

Data Processing ​

What We Process ​

  • Audio signals - Analyzed in real-time to detect tempo/BPM
  • Peak detection data - Temporary calculations for beat identification
  • BPM candidates - Results of the analysis algorithm

What We DON'T Collect or Store ​

  • ❌ No audio recording or storage
  • ❌ No data sent to external servers
  • ❌ No telemetry or analytics
  • ❌ No cookies or tracking
  • ❌ No user information
  • ❌ No third-party data sharing

How It Works ​

Client-Side Processing ​

All audio analysis happens locally in your browser:

  1. Audio data flows through the Web Audio API
  2. Analysis runs in an AudioWorklet (separate thread)
  3. Results are returned to your application
  4. No data leaves your device

Memory Management ​

  • Audio data is processed in small chunks
  • Temporary buffers are cleared after analysis
  • No persistent storage of audio information
  • Memory is automatically managed by the browser

Microphone Usage ​

When using microphone input:

Permission ​

  • Requires explicit browser permission via getUserMedia
  • You control when to request access
  • Users can deny or revoke permission at any time

Processing ​

  • Audio is analyzed in real-time only
  • No recording or saving of microphone input
  • Processing stops when you stop the analyzer
  • Audio stream is released when disconnected

Best Practices ​

For Developers:

  • Always explain why microphone access is needed before requesting
  • Provide clear visual indicators when microphone is active
  • Stop the audio stream when done: stream.getTracks().forEach(track => track.stop())
  • Handle permission denial gracefully

For Users:

  • The library never records your audio
  • Check for visual indicators (browser shows mic icon when active)
  • You can revoke permissions anytime in browser settings

Audio Files ​

When analyzing audio files:

  • Files are decoded in browser memory
  • Processing happens entirely client-side
  • No files are uploaded to any server
  • Analyzed data is temporary and not stored

Third-Party Content ​

No External Dependencies ​

  • This library has zero runtime dependencies
  • No third-party code runs during audio processing
  • No external APIs are called

Remote Audio Streams ​

If you analyze remote audio (URLs, streams):

  • Audio is fetched directly by your browser
  • Subject to CORS policies (server must allow it)
  • We don't intercept or proxy the audio
  • Privacy depends on the audio source provider

Compliance ​

GDPR & Privacy Laws ​

  • No personal data is processed by this library
  • No consent mechanisms needed (no data collection)
  • No data retention (nothing is stored)
  • No data processing agreements needed

Your Responsibility ​

As a developer using this library, you are responsible for:

  • Informing your users about your app's audio processing
  • Complying with applicable privacy laws in your jurisdiction
  • Managing permissions and user consent for your application
  • Implementing your own privacy policy if needed

Transparency ​

Open Source ​

  • All code is publicly available on GitHub
  • Fully auditable implementation
  • Community-reviewed and maintained

Audit Trail ​

You can verify our privacy claims by:

  • Reviewing the source code
  • Checking network activity (no requests are made)
  • Inspecting browser memory (no persistent storage)
  • Using browser developer tools to monitor behavior

Questions ​

If you have privacy concerns or questions:

Last updated: November 2025