Audio Routing

Author: consuelita

SignalBridge/src/main/java/org/operatorfoundation/signalbridge/internal/AudioRecordManager.kt

@@ -4,9 +4,13 @@ import android.Manifest
 import android.annotation.SuppressLint
 import android.content.Context
 import android.content.pm.PackageManager
+import android.hardware.usb.UsbDevice
 import android.media.AudioFormat
+import android.media.AudioManager
 import android.media.AudioRecord
 import android.media.MediaRecorder
+import android.os.Build
+import androidx.annotation.RequiresApi
 import androidx.core.content.ContextCompat
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.channels.awaitClose
@@ -32,7 +36,7 @@ import org.operatorfoundation.signalbridge.exceptions.AudioRecordException
  * - State management beyond AudioRecord
  * - Audio output/playback
  */
-internal class AudioRecordManager(private val context: Context)
+internal class AudioRecordManager(private val context: Context, private val usbDevice: UsbDevice? = null)
 {
     companion object
     {
@@ -56,6 +60,8 @@ internal class AudioRecordManager(private val context: Context)
     private var workingAudioSource: Int = -1
     private var bufferSize: Int = 0
     private var detectedSampleRate: Int = SAMPLE_RATE // Will be updated during initialization
+    private val audioManager = context.getSystemService(Context.AUDIO_SERVICE) as android.media.AudioManager
+
 
     /**
      * Tests multiple audio sources and initializes AudioRecord with the first working one.
@@ -65,6 +71,14 @@ internal class AudioRecordManager(private val context: Context)
     {
         Timber.d("Initializing AudioRecord")
 
+        // Set USB audio routing if we have a USB device
+        if (usbDevice != null)
+        {
+            val routingSet = setUsbAudioRouting()
+            if (routingSet) Timber.i("USB audio routing configured successfully")
+            else Timber.w("Failed to set USB audio routing, continuing with default routing")
+        }
+
         // Test each audio source until we find one that works
         for (audioSource in AUDIO_SOURCES_TO_TEST)
         {
@@ -214,6 +228,41 @@ internal class AudioRecordManager(private val context: Context)
         }
     }
 
+    /**
+     * Sets USB audio device as the preferred audio input routing
+     */
+    private fun setUsbAudioRouting(): Boolean
+    {
+        return try
+        {
+            // Get the list of available communication devices
+            val availableDevices = audioManager.availableCommunicationDevices
+
+            val audioDeviceInfo = availableDevices.find { device ->
+                device.type == android.media.AudioDeviceInfo.TYPE_USB_DEVICE &&
+                        device.productName?.toString() == usbDevice?.productName
+            }
+
+            if (audioDeviceInfo != null)
+            {
+                val success = audioManager.setCommunicationDevice(audioDeviceInfo)
+                Timber.d("Set USB device as communication device: $success")
+                success
+            }
+            else
+            {
+                Timber.w("USB audio device not found in available communication devices")
+                Timber.w("Available devices: ${availableDevices.map { it.productName }}")
+                false
+            }
+        }
+        catch (e: Exception)
+        {
+            Timber.e(e, "Failed to set USB audio routing")
+            false
+        }
+    }
+
     /**
      * Starts recording and returns a flow of raw audio samples
      * This is a pure data stream with no processing or state management

SignalBridge/src/main/java/org/operatorfoundation/signalbridge/internal/RealUsbAudioConnection.kt

@@ -87,7 +87,7 @@ internal class RealUsbAudioConnection(
             }
 
             // Create and initialize the AudioRecordManager
-            val recordManager = AudioRecordManager(context)
+            val recordManager = AudioRecordManager(context, usbDevice)
 
             // Get likely sample rates for this USB device
             val likelySampleRates = getLikelySampleRates()