Bluetooth headsets not working in WebRTCSample

fede87 commented 4 years ago

Description

We are developing a custom solution based on WebRTC tecnology running on android devices as well as on Google Glass Enterprise Edition 2 smart glasses.

We found a possible issue regarding bluetooth headset connection that we are able to reproduce on the webRTC sample. Bluetooth headsets seems not to be working during webRTC calls.

The capability of connecting bluetooth headsets is critical when the webRTC solution running on Google Glass is used in noisy environments for field services or shop assistance use cases.

Wired headsets are currently working with webRTC solutions running on Google Glass, but it is obviously needed an usb-c/jack adapter which is becoming less popular nowadays in favour of true wireless bluetooth headset devices and it is also a less ergonomic way to join a call.

Steps to Reproduce

Pair a bluetooth headset from Google Glass system settings and keep it connected and active.
Run the webRTC sample app.
Connect to the webRTC suggested room from the Google Glass sample app and connect a desktop to the same suggested room.
The audio keeps coming from the speaker and the bluetooth headset is not capable of reproducing the room audio.

Code

The error seems to be related to the bluetooth adapter proxy discover process that is never completed, the following snipped is taken from AppRTCBluetoothManager.java class:


/**
   * Implementation of an interface that notifies BluetoothProfile IPC clients when they have been
   * connected to or disconnected from the service.
   */
  private class BluetoothServiceListener implements BluetoothProfile.ServiceListener {
    @Override
    // Called to notify the client when the proxy object has been connected to the service.
    // Once we have the profile proxy object, we can use it to monitor the state of the
    // connection and perform other operations that are relevant to the headset profile.
    public void onServiceConnected(int profile, BluetoothProfile proxy) {
      if (profile != BluetoothProfile.HEADSET || bluetoothState == State.UNINITIALIZED) {
        return;
      }
      Log.d(TAG, "BluetoothServiceListener.onServiceConnected: BT state=" + bluetoothState);
      // Android only supports one connected Bluetooth Headset at a time.
      bluetoothHeadset = (BluetoothHeadset) proxy;
      updateAudioDeviceState();
      Log.d(TAG, "onServiceConnected done: BT state=" + bluetoothState);
    }

    @Override
    /** Notifies the client when the proxy object has been disconnected from the service. */
    public void onServiceDisconnected(int profile) {
      if (profile != BluetoothProfile.HEADSET || bluetoothState == State.UNINITIALIZED) {
        return;
      }
      Log.d(TAG, "BluetoothServiceListener.onServiceDisconnected: BT state=" + bluetoothState);
      stopScoAudio();
      bluetoothHeadset = null;
      bluetoothDevice = null;
      bluetoothState = State.HEADSET_UNAVAILABLE;
      updateAudioDeviceState();
      Log.d(TAG, "onServiceDisconnected done: BT state=" + bluetoothState);
    }
  }

  /**
   * Activates components required to detect Bluetooth devices and to enable
   * BT SCO (audio is routed via BT SCO) for the headset profile. The end
   * state will be HEADSET_UNAVAILABLE but a state machine has started which
   * will start a state change sequence where the final outcome depends on
   * if/when the BT headset is enabled.
   * Example of state change sequence when start() is called while BT device
   * is connected and enabled:
   *   UNINITIALIZED --> HEADSET_UNAVAILABLE --> HEADSET_AVAILABLE -->
   *   SCO_CONNECTING --> SCO_CONNECTED <==> audio is now routed via BT SCO.
   * Note that the AppRTCAudioManager is also involved in driving this state
   * change.
   */
  public void start() {

    [...]

    if (!getBluetoothProfileProxy(
            apprtcContext, bluetoothServiceListener, BluetoothProfile.HEADSET)) {
      Log.e(TAG, "BluetoothAdapter.getProfileProxy(HEADSET) failed");
      return;
    }

   [...] 

  }

  protected boolean getBluetoothProfileProxy(Context context,
  BluetoothProfile.ServiceListener listener, int profile) {
    return bluetoothAdapter.getProfileProxy(context, listener, profile);
  }

The function getBluetoothProfileProxy(Context context, BluetoothProfile.ServiceListener listener, int profile) called in the start() function is always called and always returns true, that means that the proxy retrieve process will start without any initial error, but the callback onServiceConnected(int profile, BluetoothProfile proxy) of the BluetoothServiceListener object is never been called.

The same behaviour seems to be occurring in our codebase where the bluetooth proxy retrieve process is accomplished in the same way.

The following lines are the most significant console outputs that appear just right after the getBluetoothProfileProxy(Context context, BluetoothProfile.ServiceListener listener, int profile) is called:

D/BluetoothManagerService: Creating new ProfileServiceConnections object for profile: 1
E/BluetoothManagerService: Fail to bind to: Intent { act=android.bluetooth.IBluetoothHeadset }

Expected Behavior

The onServiceConnected(int profile, BluetoothProfile proxy) of the BluetoothServiceListener object should be called or at least getBluetoothProfileProxy(Context context, BluetoothProfile.ServiceListener listener, int profile) should return false instead of true.