Implement 24/7 Android audio recorder with threshold-based noise filtering

[Copilot]

Complete Android application for continuous audio recording with basic noise gating. Implements foreground service architecture for background operation, runtime permission handling, and threshold-based amplitude filtering.

Core Components

MainActivity (174 lines)

• Runtime permission requests (RECORD_AUDIO, POST_NOTIFICATIONS)
• Service binding for live status updates
• Traditional XML layout with Material Design

RecordingService (140 lines)

• Foreground service with notification
• PARTIAL_WAKE_LOCK for continuous operation
• START_STICKY restart policy

AudioRecorder (150 lines)

• AudioRecord API: 44.1kHz, mono, PCM 16-bit
• In-place noise gate: silence samples where abs(amplitude) ≤ 500
• BufferedOutputStream for efficient I/O

Implementation Notes

Noise filtering is sample-by-sample threshold gating:

private fun applyNoiseGateInPlace(audioData: ShortArray, size: Int) {
    for (i in 0 until size) {
        if (abs(audioData[i].toInt()) <= noiseThreshold) {
            audioData[i] = 0  // Silence below threshold
        }
    }
}

Permissions cover all Android API levels (26+):

• RECORD_AUDIO, WAKE_LOCK, FOREGROUND_SERVICE
• FOREGROUND_SERVICE_MICROPHONE (API 34+)
• POST_NOTIFICATIONS (API 33+)

Output: Raw PCM files in app-specific storage, timestamped.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• dl.google.com
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED -Xmx2048m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -cp /home/REDACTED/.gradle/wrapper/dists/gradle-8.2-bin/bbg7u40eoinfdyxsxr3z4i7ta/gradle-8.2/lib/gradle-launcher-8.2.jar -javaagent:/home/REDACTED/.gradle/wrapper/dists/gradle-8.2-bin/bbg7u40eoinfdyxsxr3z4i7ta/gradle-8.2/lib/agents/gradle-instrumentation-agent-8.2.jar org.gradle.launcher.daemon.bootstrap.GradleDaemon 8.2 (dns block)
• google.com
  • Triggering command: ping -c 2 google.com (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

Create a basic Android app in Kotlin for continuous 24/7 audio recording with noise filtering. Include:

• MainActivity with recording controls
• Foreground service for background recording
• AudioRecord API usage
• Basic noise gating logic (threshold-based)
• Proper permissions (RECORD_AUDIO, WAKE_LOCK, foreground service)
• Modern Android project structure (app/, build.gradle.kts optional)
  Use Jetpack components if needed. No Jetpack Compose — use traditional XML layouts.

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