commit c0896c7d3361f1209822dd9f5e763c03bb4c4ce7
author Andy Hung <hunga@google.com> Fri Oct 21 17:30:30 2022 -0700
committer Andy Hung <hunga@google.com> Tue Nov 15 17:02:52 2022 -0800
tree 4cef95523781b45b38eb297f69cd22a29a4b9130
parent 3c48ad9e639c2cc303c178058100920d144f6256

Spatializer: Workaround for Head Tracking on BT AAC

As the BT HAL doesn't report low latency reliably,
it is not required to enable Head Tracking.

Nevertheless we always request low latency for
head tracking if the HAL supports it.

Test: Head Tracking works over AAC HT Buds
Bug: 253297301
Merged-In: I6e372603a9f69c7bd9eb0434d18208f61fd9b78d
Change-Id: I6e372603a9f69c7bd9eb0434d18208f61fd9b78d

services/audiopolicy/service/Spatializer.cpp

diff --git a/services/audiopolicy/service/Spatializer.cpp b/services/audiopolicy/service/Spatializer.cpp
index be95d58..38ad494 100644
--- a/services/audiopolicy/service/Spatializer.cpp
+++ b/services/audiopolicy/service/Spatializer.cpp
@@ -935,12 +935,15 @@
 
 void Spatializer::checkSensorsState_l() {
     audio_latency_mode_t requestedLatencyMode = AUDIO_LATENCY_MODE_FREE;
-    bool lowLatencySupported = mSupportedLatencyModes.empty()
-            || (std::find(mSupportedLatencyModes.begin(), mSupportedLatencyModes.end(),
-                    AUDIO_LATENCY_MODE_LOW) != mSupportedLatencyModes.end());
+    const bool supportsSetLatencyMode = !mSupportedLatencyModes.empty();
+    const bool supportsLowLatencyMode = supportsSetLatencyMode && std::find(
+            mSupportedLatencyModes.begin(), mSupportedLatencyModes.end(),
+            AUDIO_LATENCY_MODE_LOW) != mSupportedLatencyModes.end();
     if (mSupportsHeadTracking) {
         if (mPoseController != nullptr) {
-            if (lowLatencySupported && mNumActiveTracks > 0 && mLevel != SpatializationLevel::NONE
+            // TODO(b/253297301, b/255433067) reenable low latency condition check
+            // for Head Tracking after Bluetooth HAL supports it correctly.
+            if (mNumActiveTracks > 0 && mLevel != SpatializationLevel::NONE
                 && mDesiredHeadTrackingMode != HeadTrackingMode::STATIC
                 && mHeadSensor != SpatializerPoseController::INVALID_SENSOR) {
                 if (mEngine != nullptr) {
@@ -949,7 +952,7 @@
                 }
                 mPoseController->setHeadSensor(mHeadSensor);
                 mPoseController->setScreenSensor(mScreenSensor);
-                requestedLatencyMode = AUDIO_LATENCY_MODE_LOW;
+                if (supportsLowLatencyMode) requestedLatencyMode = AUDIO_LATENCY_MODE_LOW;
             } else {
                 mPoseController->setHeadSensor(SpatializerPoseController::INVALID_SENSOR);
                 mPoseController->setScreenSensor(SpatializerPoseController::INVALID_SENSOR);
@@ -959,7 +962,7 @@
             resetEngineHeadPose_l();
         }
     }
-    if (mOutput != AUDIO_IO_HANDLE_NONE) {
+    if (mOutput != AUDIO_IO_HANDLE_NONE && supportsSetLatencyMode) {
         AudioSystem::setRequestedLatencyMode(mOutput, requestedLatencyMode);
     }
 }