Explicitly mute the audio output while switching the A2DP Active Device

The mute/unmute of the audio output is needed during the A2DP
ActiveDevice switch to avoid audio glitches.

Bug: 78152025
Bug: 110441865
Test: Manual - stream with Pandora/Spotify and switch A2DP Active Device
Change-Id: I5a233460a07e0d4fffcb4e6cb208d846517f0c1e
(cherry picked from commit 075005f0ef8adf5397b9ed6210e0160f1a0314a5)

1 files changed, 11 insertions, 0 deletions

diff --git a/src/com/android/bluetooth/a2dp/A2dpService.java b/src/com/android/bluetooth/a2dp/A2dpService.java
index 10a2f8b5d..64a9cad6c 100644
--- a/src/com/android/bluetooth/a2dp/A2dpService.java
+++ b/src/com/android/bluetooth/a2dp/A2dpService.java
@@ -517,7 +517,14 @@ public class A2dpService extends ProfileService {
                 }
                 // Make sure the Audio Manager knows the previous Active device is disconnected,
                 // and the new Active device is connected.
+                // Also, mute and unmute the output during the switch to avoid audio glitches.
+                boolean wasMuted = false;
                 if (previousActiveDevice != null) {
+                    if (!mAudioManager.isStreamMute(AudioManager.STREAM_MUSIC)) {
+                        mAudioManager.adjustStreamVolume(AudioManager.STREAM_MUSIC,
+                                                         AudioManager.ADJUST_MUTE, 0);
+                        wasMuted = true;
+                    }
                     mAudioManager.setBluetoothA2dpDeviceConnectionStateSuppressNoisyIntent(
                             previousActiveDevice, BluetoothProfile.STATE_DISCONNECTED,
                             BluetoothProfile.A2DP, true, -1);
@@ -539,6 +546,10 @@ public class A2dpService extends ProfileService {
                 // change, so the Audio Service can reset accordingly the audio
                 // feeding parameters in the Audio HAL to the Bluetooth stack.
                 mAudioManager.handleBluetoothA2dpDeviceConfigChange(mActiveDevice);
+                if (wasMuted) {
+                    mAudioManager.adjustStreamVolume(AudioManager.STREAM_MUSIC,
+                                                     AudioManager.ADJUST_UNMUTE, 0);
+                }
             }
         }
         return true;