diff --git a/media/libaaudio/src/Android.bp b/media/libaaudio/src/Android.bp
index ddd3f97..38bcb7c 100644
--- a/media/libaaudio/src/Android.bp
+++ b/media/libaaudio/src/Android.bp
@@ -211,6 +211,7 @@
         "flowgraph/ClipToRange.cpp",
         "flowgraph/FlowGraphNode.cpp",
         "flowgraph/ManyToMultiConverter.cpp",
+        "flowgraph/MonoBlend.cpp",
         "flowgraph/MonoToMultiConverter.cpp",
         "flowgraph/MultiToMonoConverter.cpp",
         "flowgraph/RampLinear.cpp",
diff --git a/media/libaaudio/src/client/AAudioFlowGraph.cpp b/media/libaaudio/src/client/AAudioFlowGraph.cpp
index 68b84c8..d3e2912 100644
--- a/media/libaaudio/src/client/AAudioFlowGraph.cpp
+++ b/media/libaaudio/src/client/AAudioFlowGraph.cpp
@@ -21,6 +21,7 @@
 #include "AAudioFlowGraph.h"
 
 #include <flowgraph/ClipToRange.h>
+#include <flowgraph/MonoBlend.h>
 #include <flowgraph/MonoToMultiConverter.h>
 #include <flowgraph/RampLinear.h>
 #include <flowgraph/SinkFloat.h>
@@ -37,7 +38,8 @@
 aaudio_result_t AAudioFlowGraph::configure(audio_format_t sourceFormat,
                           int32_t sourceChannelCount,
                           audio_format_t sinkFormat,
-                          int32_t sinkChannelCount) {
+                          int32_t sinkChannelCount,
+                          bool useMonoBlend) {
     FlowGraphPortFloatOutput *lastOutput = nullptr;
 
     // TODO change back to ALOGD
@@ -76,6 +78,12 @@
         lastOutput = &mClipper->output;
     }
 
+    if (useMonoBlend) {
+        mMonoBlend = std::make_unique<MonoBlend>(sourceChannelCount);
+        lastOutput->connect(&mMonoBlend->input);
+        lastOutput = &mMonoBlend->output;
+    }
+
     // Expand the number of channels if required.
     if (sourceChannelCount == 1 && sinkChannelCount > 1) {
         mChannelConverter = std::make_unique<MonoToMultiConverter>(sinkChannelCount);
diff --git a/media/libaaudio/src/client/AAudioFlowGraph.h b/media/libaaudio/src/client/AAudioFlowGraph.h
index 079328a..e719d91 100644
--- a/media/libaaudio/src/client/AAudioFlowGraph.h
+++ b/media/libaaudio/src/client/AAudioFlowGraph.h
@@ -24,6 +24,7 @@
 
 #include <aaudio/AAudio.h>
 #include <flowgraph/ClipToRange.h>
+#include <flowgraph/MonoBlend.h>
 #include <flowgraph/MonoToMultiConverter.h>
 #include <flowgraph/RampLinear.h>
 
@@ -41,7 +42,8 @@
     aaudio_result_t configure(audio_format_t sourceFormat,
                               int32_t sourceChannelCount,
                               audio_format_t sinkFormat,
-                              int32_t sinkChannelCount);
+                              int32_t sinkChannelCount,
+                              bool useMonoBlend);
 
     void process(const void *source, void *destination, int32_t numFrames);
 
@@ -54,6 +56,7 @@
 
 private:
     std::unique_ptr<flowgraph::FlowGraphSourceBuffered>     mSource;
+    std::unique_ptr<flowgraph::MonoBlend>                   mMonoBlend;
     std::unique_ptr<flowgraph::RampLinear>                  mVolumeRamp;
     std::unique_ptr<flowgraph::ClipToRange>                 mClipper;
     std::unique_ptr<flowgraph::MonoToMultiConverter>        mChannelConverter;
diff --git a/media/libaaudio/src/client/AudioStreamInternal.cpp b/media/libaaudio/src/client/AudioStreamInternal.cpp
index 89d42bf..1b8e224 100644
--- a/media/libaaudio/src/client/AudioStreamInternal.cpp
+++ b/media/libaaudio/src/client/AudioStreamInternal.cpp
@@ -27,6 +27,7 @@
 #include <aaudio/AAudio.h>
 #include <cutils/properties.h>
 
+#include <media/AudioParameter.h>
 #include <media/AudioSystem.h>
 #include <media/MediaMetricsItem.h>
 #include <utils/Trace.h>
@@ -270,6 +271,15 @@
         mCallbackBuffer = std::make_unique<uint8_t[]>(callbackBufferSize);
     }
 
+    // Exclusive output streams should combine channels when mono audio adjustment
+    // is enabled.
+    if ((getDirection() == AAUDIO_DIRECTION_OUTPUT) &&
+        (getSharingMode() == AAUDIO_SHARING_MODE_EXCLUSIVE)) {
+        bool isMasterMono = false;
+        android::AudioSystem::getMasterMono(&isMasterMono);
+        setRequireMonoBlend(isMasterMono);
+    }
+
     // For debugging and analyzing the distribution of MMAP timestamps.
     // For OUTPUT, use a NEGATIVE offset to move the CPU writes further BEFORE the HW reads.
     // For INPUT, use a POSITIVE offset to move the CPU reads further AFTER the HW writes.
diff --git a/media/libaaudio/src/client/AudioStreamInternalPlay.cpp b/media/libaaudio/src/client/AudioStreamInternalPlay.cpp
index 5921799..c17c7a0 100644
--- a/media/libaaudio/src/client/AudioStreamInternalPlay.cpp
+++ b/media/libaaudio/src/client/AudioStreamInternalPlay.cpp
@@ -52,7 +52,8 @@
         result = mFlowGraph.configure(getFormat(),
                              getSamplesPerFrame(),
                              getDeviceFormat(),
-                             getDeviceChannelCount());
+                             getDeviceChannelCount(),
+                             getRequireMonoBlend());
 
         if (result != AAUDIO_OK) {
             safeReleaseClose();
diff --git a/media/libaaudio/src/core/AudioStream.h b/media/libaaudio/src/core/AudioStream.h
index afb8551..a3af753 100644
--- a/media/libaaudio/src/core/AudioStream.h
+++ b/media/libaaudio/src/core/AudioStream.h
@@ -277,6 +277,10 @@
         return mIsPrivacySensitive;
     }
 
+    bool getRequireMonoBlend() const {
+        return mRequireMonoBlend;
+    }
+
     /**
      * This is only valid after setChannelMask() and setFormat()
      * have been called.
@@ -631,6 +635,13 @@
         mIsPrivacySensitive = privacySensitive;
     }
 
+    /**
+     * This should not be called after the open() call.
+     */
+    void setRequireMonoBlend(bool requireMonoBlend) {
+        mRequireMonoBlend = requireMonoBlend;
+    }
+
     std::string mMetricsId; // set once during open()
 
     std::mutex                 mStreamLock;
@@ -672,6 +683,7 @@
     aaudio_input_preset_t       mInputPreset     = AAUDIO_UNSPECIFIED;
     aaudio_allowed_capture_policy_t mAllowedCapturePolicy = AAUDIO_ALLOW_CAPTURE_BY_ALL;
     bool                        mIsPrivacySensitive = false;
+    bool                        mRequireMonoBlend = false;
 
     int32_t                     mSessionId = AAUDIO_UNSPECIFIED;
 
diff --git a/media/libaaudio/src/flowgraph/MonoBlend.cpp b/media/libaaudio/src/flowgraph/MonoBlend.cpp
new file mode 100644
index 0000000..62e2809
--- /dev/null
+++ b/media/libaaudio/src/flowgraph/MonoBlend.cpp
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <unistd.h>
+
+#include "MonoBlend.h"
+
+using namespace flowgraph;
+
+MonoBlend::MonoBlend(int32_t channelCount)
+        : FlowGraphFilter(channelCount)
+        , mInvChannelCount(1. / channelCount)
+{
+}
+
+int32_t MonoBlend::onProcess(int32_t numFrames) {
+    int32_t channelCount = output.getSamplesPerFrame();
+    const float *inputBuffer = input.getBuffer();
+    float *outputBuffer = output.getBuffer();
+
+    for (size_t i = 0; i < numFrames; ++i) {
+        float accum = 0;
+        for (size_t j = 0; j < channelCount; ++j) {
+            accum += *inputBuffer++;
+        }
+        accum *= mInvChannelCount;
+        for (size_t j = 0; j < channelCount; ++j) {
+            *outputBuffer++ = accum;
+        }
+    }
+
+    return numFrames;
+}
\ No newline at end of file
diff --git a/media/libaaudio/src/flowgraph/MonoBlend.h b/media/libaaudio/src/flowgraph/MonoBlend.h
new file mode 100644
index 0000000..7e3c35b
--- /dev/null
+++ b/media/libaaudio/src/flowgraph/MonoBlend.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FLOWGRAPH_MONO_BLEND_H
+#define FLOWGRAPH_MONO_BLEND_H
+
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "FlowGraphNode.h"
+
+namespace flowgraph {
+
+/**
+ * Combine data between multiple channels so each channel is an average
+ * of all channels.
+ */
+class MonoBlend : public FlowGraphFilter {
+public:
+    explicit MonoBlend(int32_t channelCount);
+
+    virtual ~MonoBlend() = default;
+
+    int32_t onProcess(int32_t numFrames) override;
+
+    const char *getName() override {
+        return "MonoBlend";
+    }
+private:
+    const float mInvChannelCount;
+};
+
+} /* namespace flowgraph */
+
+#endif //FLOWGRAPH_MONO_BLEND