🎤 Sound Monitor - Automatic Sound-Triggered Recording

A powerful Android application that automatically records video when ambient sound levels exceed a configurable threshold. Perfect for security monitoring, event documentation, and capturing unexpected moments.

🌟 Features

🎯 Core Functionality

Automatic Sound Detection: Continuously monitors ambient audio levels
Smart Recording: Automatically starts recording when sound exceeds threshold
Dual Recording Modes: Video + Audio or Audio-only recording
Configurable Sensitivity: Adjustable sound threshold (30-90 dB range)
Auto-Stop Timer: Configurable timeout (1-30 seconds) after sound drops below threshold

📱 User Interface

Real-time dB Display: Live audio level monitoring with color-coded indicators
Simple Controls: One-button start/stop with intuitive status display
Camera Selection: Switch between front and rear camera
Recording Mode Toggle: Quick switch between video and audio-only modes

🔒 Hybrid Legal Verification System

Real-Time Timestamp Proof: Creates verification BEFORE recording begins
RFC 3161 Certification: Industry-standard legal timestamp certification
Network Time Enforcement: Requires independent time verification (no local fallback)
Cryptographic Binding: 256-bit seed links timestamp proof to video hash
GPS Location Proof: Precise coordinates with accuracy metrics and Google Maps integration
Tamper-Proof Evidence: Cryptographically impossible to forge timestamps post-recording
Court-Ready Documentation: Comprehensive legal evidence files for proceedings
Fail-Safe Design: Recording blocked if network time verification unavailable

📁 File Management

Public Storage Access: Recordings automatically saved to Downloads/SoundTrigger/
MediaStore Integration: Videos appear in device gallery automatically
USB/MTP Compatible: Easy access when connected to computer
Organized Structure: Each session creates separate folders with metadata

🛠️ Technical Features

Background Monitoring: Foreground service for reliable operation
Permission Management: Smart runtime permission requests
Network Testing: Built-in connectivity and GPS diagnostics
Camera Preview: Live camera stream for framing and testing
Scoped Storage: Android 10+ compatible file storage

📋 Requirements

Android 5.0 (API level 21) or higher
Camera access for video recording
Microphone access for audio monitoring
Storage access for saving recordings
Location access for GPS verification (optional)
Network access for timestamp verification (optional)

🚀 Installation

From Source

Clone the repository:

git clone https://github.com/your-username/SoundMonitor.git
cd SoundMonitor

Build and install:
```
./gradlew installDebug
```

APK Installation

Download the latest APK from Releases
Enable "Install from Unknown Sources" in Android settings
Install the APK file

📖 Usage Guide

Initial Setup

Grant Permissions: Allow Camera, Microphone, Location, and Notification access
Set Threshold: Adjust the sound sensitivity slider (recommended: 50-70 dB)
Choose Mode: Select Video+Audio or Audio-only recording
Select Camera: Choose front or rear camera for video mode

Basic Operation

Start Monitoring: Tap "Start Monitoring" button
Automatic Recording: App will automatically record when sound exceeds threshold
Live Feedback: Watch real-time dB levels and recording status
Stop Monitoring: Tap "Stop Monitoring" when done

Recording Modes

📹 Video Mode (Default)

Records 1280x720 HD video at 30fps
Includes audio track with clear sound quality
2Mbps bitrate for good quality/size balance
Automatic timeout after sound level drops

🎵 Audio-Only Mode

Records high-quality audio files
Smaller file sizes and longer battery life
No automatic timeout (manual stop required)
Perfect for voice recording or music capture

Advanced Features

🧪 Testing Tools

Network Test: Verify internet connectivity for timestamp services
GPS Test: Check location accuracy and provider status
Camera Preview: Test camera and framing before recording

📁 File Access

Recordings Button: Quick access to recorded files
Downloads Folder: Navigate to Downloads/SoundTrigger/
USB Transfer: Connect to computer for easy file management

📂 File Structure

Downloads/SoundTrigger/
├── video_YYYYMMDD_HHMMSS.mp4          # Video recordings
├── video_YYYYMMDD_HHMMSS_timestamp.txt # Legal verification
├── audio_YYYYMMDD_HHMMSS.m4a          # Audio recordings
└── audio_YYYYMMDD_HHMMSS_timestamp.txt # Audio verification

Hybrid Verification Files

Each recording includes comprehensive legal evidence documentation:

Recording Start Proof: Created BEFORE video recording begins
Network Time Authority: Independent time source verification (TimeAPI.io, etc.)
RFC 3161 Certificate: Industry-standard legal timestamp certification
Cryptographic Seed: 256-bit hash binding timestamp to video
GPS Coordinates: Precise location with accuracy metrics and Google Maps links
Video Verification: Proof that video was recorded after timestamp creation
Legal Explanation: Step-by-step verification process for court presentation
File Hash: SHA-256 with cryptographic seed for tamper detection
Backward Compatibility: Legacy timestamp format included

⚖️ Legal Evidence Features

Hybrid Verification System

Pre-Recording Proof: Timestamp created BEFORE any video data exists
Cryptographic Binding: 256-bit seed mathematically links proof to video
Network Time Enforcement: Zero tolerance for manipulatable local device time
RFC 3161 Certification: Industry-standard legal timestamp servers
Fail-Safe Operation: Recording blocked without independent time verification

Cryptographic Verification

Seeded SHA-256 Hashing: Video hash includes cryptographic seed from start proof
Tamper Detection: Any modification changes the hash completely
Integrity Guarantee: Mathematical proof video matches original timestamp
Post-Recording Verification: Proves video was created after start proof

Time Verification

HTTPS-Only Providers: TimeAPI.io, IPGeolocation, TimezoneDB
20-Second Mobile Timeout: Optimized for cellular networks
No Local Fallback: Prevents "I changed my phone's clock" legal defense
Authority Documentation: Records exact time source and certificate
Legal-Grade Standards: Court-admissible timestamp certification

Location Proof

Multi-Provider GPS: GPS → Network → Passive location fallback
Accuracy Metrics: Precision measurements with age verification
Google Maps Integration: Direct links for location verification
Plus Codes: Alternative location verification system
Provider Documentation: Records GPS source and quality metrics

Court Readiness

Expert Witness Support: Technical documentation for testimony
Verification Steps: Complete instructions for legal validation
Standards Compliance: RFC 3161, SHA-256, GPS industry standards
Unbreakable Chain: Cryptographically impossible to forge evidence
Clear Documentation: Legal explanations for non-technical audiences

🔧 Technical Specifications

Audio Processing

Sample Rate: 44.1kHz (CD quality)
Format: 16-bit PCM, Mono channel
Threshold Range: 30-90 dB with 1 dB precision
Update Rate: 100ms real-time monitoring
Source: MediaRecorder.AudioSource.MIC

Video Recording

Resolution: 1280x720 (HD)
Frame Rate: 30fps constant
Bitrate: 2Mbps for quality/size balance
Format: H.264/AAC in MP4 container
Camera API: Legacy API for background compatibility

Storage & Compatibility

Target SDK: 33 (Android 13)
Minimum SDK: 21 (Android 5.0)
Storage: MediaStore API (Android 10+ compatible)
Permissions: Runtime permission system
Background: Foreground service for reliability

🔍 Troubleshooting

Common Issues

Recording Not Starting

Check microphone permissions
Verify sound threshold isn't too high
Ensure app isn't in battery optimization
Test with Camera Preview first

Files Not Found

Use "Open Recording Folder" button
Check Downloads/SoundTrigger directory
Verify storage permissions granted
Try USB connection to computer

Poor Audio Quality

Move closer to sound source
Reduce background noise
Check microphone isn't blocked
Adjust threshold sensitivity

Network Time Verification Failed

Check internet connectivity (WiFi + mobile data)
Use Network Test feature to diagnose issues
Recording will be BLOCKED without network time
Ensure TimeAPI.io, IPGeolocation, or TimezoneDB are accessible
Check firewall/proxy settings blocking HTTPS requests

Performance Tips

Battery Optimization: Disable for app in Android settings
Storage Space: Ensure adequate free space available
Network Connection: WiFi recommended for timestamp services
Device Performance: Close unnecessary apps during recording

🛡️ Privacy & Security

Local Processing: All audio analysis done on-device
No Cloud Storage: Recordings stay on your device
Network Usage: Only for timestamp verification (optional)
Permission Control: Only requests necessary permissions
Data Protection: Files stored in secure app directory

🔄 Updates & Changelog

Version 1.0 (Current)

✅ Automatic sound-triggered recording
✅ Dual recording modes (Video + Audio-only)
✅ Hybrid Timestamp Verification System (NEW!)
✅ RFC 3161 Legal Certification (NEW!)
✅ Network Time Enforcement - No local fallback (NEW!)
✅ Cryptographic Proof Binding (NEW!)
✅ GPS location proof with accuracy metrics
✅ Real-time audio monitoring with color coding
✅ Configurable sensitivity and timeout
✅ Public storage with MediaStore API
✅ Background service operation
✅ Network and GPS testing tools
✅ Camera preview and selection
✅ HTTPS-only time providers for security

🤝 Contributing

Contributions are welcome! Please feel free to submit pull requests or open issues for bugs and feature requests.

Development Setup

# Clone the repository
git clone https://github.com/your-username/SoundMonitor.git

# Build the project
./gradlew build

# Install on device
./gradlew installDebug

# Run tests
./gradlew test

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

TimeAPI.io for reliable HTTPS timestamp services
RFC 3161 timestamp server protocol for legal certification
Android MediaStore API for modern storage access
Google Location Services for GPS verification
SHA-256 cryptographic hashing for integrity
IPGeolocation and TimezoneDB for backup time verification

📞 Support

For support, questions, or feature requests:

Open an Issue
Check Troubleshooting section
Review Usage Guide

Made with ❤️ for Android security and documentation needs

amastbau/SoundMonitor