feat(Android): Mute other audio streams when recording.

closes #295, closes #276

record_android/CHANGELOG.md

@@ -1,7 +1,9 @@
 ## 1.2.0
 * feat: Re-introduced native MediaRecorder. Set `RecordConfig.androidConfig.useLegacy` to `true`. This comes with limitations compared to advanced recorder.
 * feat: Advanced AudioRecorder will try to adjust given configuration if unsupported or out of range (sample rate, bitrate and channel count).
-Those two above should help for older devices or bad vendor implementations.
+  * Those two features should help for older devices, bad vendor implementations or misusage of configuration values.
+* feat: ability to mute all audio streams when recording. The settings are restored when the recording is stopped.
+  * Notice: streams will stay at current state on pause/resume.
 
 ## 1.1.0
 * fix: Properly close container when recording is stopped.

record_android/android/src/main/kotlin/com/llfbandit/record/methodcall/MethodCallHandlerImpl.kt

@@ -153,6 +153,7 @@ class MethodCallHandlerImpl(
             Utils.firstNonNull(call.argument("echoCancel"), false),
             Utils.firstNonNull(call.argument("noiseSuppress"), false),
             Utils.firstNonNull(androidConfig?.get("useLegacy") as Boolean?, false),
+            Utils.firstNonNull(androidConfig?.get("muteAudio") as Boolean?, false),
         )
     }
 }

record_android/android/src/main/kotlin/com/llfbandit/record/methodcall/RecorderWrapper.kt

@@ -148,7 +148,8 @@ internal class RecorderWrapper(
 
         return AudioRecorder(
             recorderStateStreamHandler,
-            recorderRecordStreamHandler
+            recorderRecordStreamHandler,
+            context
         )
     }
 

record_android/android/src/main/kotlin/com/llfbandit/record/record/RecordConfig.kt

@@ -13,6 +13,7 @@ class RecordConfig(
     val echoCancel: Boolean = false,
     val noiseSuppress: Boolean = false,
     val useLegacy: Boolean = false,
+    val muteAudio: Boolean = false,
 ) {
     val numChannels: Int = 2.coerceAtMost(1.coerceAtLeast(numChannels))
 }

record_android/android/src/main/kotlin/com/llfbandit/record/record/recorder/AudioRecorder.kt

@@ -1,11 +1,14 @@
 package com.llfbandit.record.record.recorder
 
+import android.content.Context
+import android.media.AudioManager
 import android.util.Log
 import com.llfbandit.record.record.RecordConfig
 import com.llfbandit.record.record.RecordState
 import com.llfbandit.record.record.stream.RecorderRecordStreamHandler
 import com.llfbandit.record.record.stream.RecorderStateStreamHandler
 
+
 interface OnAudioRecordListener {
     fun onRecord()
     fun onPause()
@@ -17,27 +20,53 @@ interface OnAudioRecordListener {
 class AudioRecorder(
     // Recorder streams
     private val recorderStateStreamHandler: RecorderStateStreamHandler,
-    private val recorderRecordStreamHandler: RecorderRecordStreamHandler
+    private val recorderRecordStreamHandler: RecorderRecordStreamHandler,
+    private val appContext: Context
 ) : IRecorder, OnAudioRecordListener {
     companion object {
         private val TAG = AudioRecorder::class.java.simpleName
     }
 
     // Recorder thread with which we will interact
     private var recorderThread: RecordThread? = null
+
     // Amplitude
     private var maxAmplitude = -160.0
+
     // Recording config
     private var config: RecordConfig? = null
+
     // Stop callback to be synchronized between stop method return & record stop
     private var stopCb: ((path: String?) -> Unit)? = null
 
+    private var muteSettings = HashMap<Int, Int>()
+    private val muteStreams = arrayOf(
+        AudioManager.STREAM_ALARM,
+        AudioManager.STREAM_DTMF,
+        AudioManager.STREAM_MUSIC,
+        AudioManager.STREAM_NOTIFICATION,
+        AudioManager.STREAM_RING,
+        AudioManager.STREAM_SYSTEM,
+        AudioManager.STREAM_VOICE_CALL,
+    )
+
+    init {
+        initMuteSettings()
+    }
+
+    /**
+     * Starts the recording with the given config.
+     */
     @Throws(Exception::class)
     override fun start(config: RecordConfig) {
         this.config = config
 
         recorderThread = RecordThread(config, this)
         recorderThread!!.startRecording()
+
+        if (config.muteAudio) {
+            muteAudio(true)
+        }
     }
 
     override fun stop(stopCb: ((path: String?) -> Unit)?) {
@@ -86,6 +115,10 @@ class AudioRecorder(
     }
 
     override fun onStop() {
+        if (config?.muteAudio == true) {
+            muteAudio(false)
+        }
+
         stopCb?.invoke(config?.path)
         stopCb = null
 
@@ -100,4 +133,26 @@ class AudioRecorder(
     override fun onAudioChunk(chunk: ByteArray) {
         recorderRecordStreamHandler.sendRecordChunkEvent(chunk)
     }
+
+    private fun muteAudio(mute: Boolean) {
+        val audioManager = appContext.getSystemService(Context.AUDIO_SERVICE) as AudioManager
+
+        val muteValue = -100    // AudioManager.ADJUST_MUTE
+        val unmuteValue = 100   // AudioManager.ADJUST_UNMUTE
+
+        muteStreams.forEach { stream ->
+            val volumeLevel = if (mute) muteValue else (muteSettings[stream] ?: unmuteValue)
+            audioManager.setStreamVolume(stream, volumeLevel, 0)
+        }
+    }
+
+    private fun initMuteSettings() {
+        muteSettings.clear()
+
+        val audioManager = appContext.getSystemService(Context.AUDIO_SERVICE) as AudioManager
+
+        muteStreams.forEach { stream ->
+            muteSettings[stream] = audioManager.getStreamVolume(stream)
+        }
+    }
 }

record_platform_interface/lib/src/types/record_config.dart

@@ -78,21 +78,33 @@ class RecordConfig {
   }
 }
 
-/// Android specific configuration
+/// Android specific configuration for recording.
 class AndroidRecordConfig {
   /// Uses Android MediaRecorder if [true].
   ///
   /// Uses advanced recorder with media codecs and additionnal features
   /// by default.
   final bool useLegacy;
 
+  /// If [true], this will mute all audio streams like alarms, music, ring, ...
+  ///
+  /// This is useful when you want to record audio without any background noise.
+  ///
+  /// The streams are restored to their previous state after recording is stopped
+  /// and will stay at current state on pause/resume.
+  ///
+  /// Use at your own risks!
+  final bool muteAudio;
+
   const AndroidRecordConfig({
     this.useLegacy = false,
+    this.muteAudio = false,
   });
 
   Map<String, dynamic> toMap() {
     return {
       'useLegacy': useLegacy,
+      'muteAudio': muteAudio,
     };
   }
 }