diff --git a/include/private/media/AudioTrackShared.h b/include/private/media/AudioTrackShared.h
index 8aec80d..9cabd8b 100644
--- a/include/private/media/AudioTrackShared.h
+++ b/include/private/media/AudioTrackShared.h
@@ -614,6 +614,8 @@
     // and thus which resulted in an underrun.
     virtual uint32_t    getUnderrunFrames() const { return mCblk->u.mStreaming.mUnderrunFrames; }
 
+    virtual uint32_t    getUnderrunCount() const { return mCblk->u.mStreaming.mUnderrunCount; }
+
     // Return the playback speed and pitch read atomically. Not multi-thread safe on server side.
     AudioPlaybackRate getPlaybackRate();
 
diff --git a/media/libmediametrics/include/MediaMetricsConstants.h b/media/libmediametrics/include/MediaMetricsConstants.h
index 00da69a..ec0e133 100644
--- a/media/libmediametrics/include/MediaMetricsConstants.h
+++ b/media/libmediametrics/include/MediaMetricsConstants.h
@@ -37,6 +37,11 @@
 // They must be appended with another value to make a key.
 #define AMEDIAMETRICS_KEY_PREFIX_AUDIO "audio."
 
+// The AudioMmap key appends the "trackId" to the prefix.
+// This is the AudioFlinger equivalent of the AAudio Stream.
+// TODO: unify with AMEDIAMETRICS_KEY_PREFIX_AUDIO_STREAM
+#define AMEDIAMETRICS_KEY_PREFIX_AUDIO_MMAP  AMEDIAMETRICS_KEY_PREFIX_AUDIO "mmap."
+
 // The AudioRecord key appends the "trackId" to the prefix.
 #define AMEDIAMETRICS_KEY_PREFIX_AUDIO_RECORD AMEDIAMETRICS_KEY_PREFIX_AUDIO "record."
 
@@ -95,6 +100,14 @@
 #define AMEDIAMETRICS_PROP_CHANNELCOUNT   "channelCount"   // int32
 #define AMEDIAMETRICS_PROP_CHANNELMASK    "channelMask"    // int32
 #define AMEDIAMETRICS_PROP_CONTENTTYPE    "contentType"    // string attributes (AudioTrack)
+#define AMEDIAMETRICS_PROP_CUMULATIVETIMENS "cumulativeTimeNs" // int64_t playback/record time
+                                                           // since start
+// DEVICE values are averaged since starting on device
+#define AMEDIAMETRICS_PROP_DEVICELATENCYMS "deviceLatencyMs" // double - avg latency time
+#define AMEDIAMETRICS_PROP_DEVICESTARTUPMS "deviceStartupMs" // double - avg startup time
+#define AMEDIAMETRICS_PROP_DEVICETIMENS   "deviceTimeNs"   // int64_t playback/record time
+#define AMEDIAMETRICS_PROP_DEVICEVOLUME   "deviceVolume"   // double - average device volume
+
 #define AMEDIAMETRICS_PROP_DIRECTION      "direction"      // string AAudio input or output
 #define AMEDIAMETRICS_PROP_DURATIONNS     "durationNs"     // int64 duration time span
 #define AMEDIAMETRICS_PROP_ENCODING       "encoding"       // string value of format
@@ -105,7 +118,9 @@
 
 #define AMEDIAMETRICS_PROP_FRAMECOUNT     "frameCount"     // int32
 #define AMEDIAMETRICS_PROP_INPUTDEVICES   "inputDevices"   // string value
+#define AMEDIAMETRICS_PROP_INTERVALCOUNT  "intervalCount"  // int32
 #define AMEDIAMETRICS_PROP_LATENCYMS      "latencyMs"      // double value
+#define AMEDIAMETRICS_PROP_NAME           "name"           // string value
 #define AMEDIAMETRICS_PROP_ORIGINALFLAGS  "originalFlags"  // int32
 #define AMEDIAMETRICS_PROP_OUTPUTDEVICES  "outputDevices"  // string value
 #define AMEDIAMETRICS_PROP_PERFORMANCEMODE "performanceMode"    // string value, "none", lowLatency"
@@ -129,6 +144,7 @@
 #define AMEDIAMETRICS_PROP_TRACKID        "trackId"        // int32 port id of track/record
 #define AMEDIAMETRICS_PROP_TYPE           "type"           // string (thread type)
 #define AMEDIAMETRICS_PROP_UNDERRUN       "underrun"       // int32
+#define AMEDIAMETRICS_PROP_UNDERRUNFRAMES "underrunFrames" // int64_t from Thread
 #define AMEDIAMETRICS_PROP_USAGE          "usage"          // string attributes (ATrack)
 #define AMEDIAMETRICS_PROP_VOLUME_LEFT    "volume.left"    // double (AudioTrack)
 #define AMEDIAMETRICS_PROP_VOLUME_RIGHT   "volume.right"   // double (AudioTrack)
@@ -140,12 +156,14 @@
 // Values are strings accepted for a given property.
 
 // An event is a general description, which often is a function name.
+#define AMEDIAMETRICS_PROP_EVENT_VALUE_BEGINAUDIOINTERVALGROUP "beginAudioIntervalGroup"
 #define AMEDIAMETRICS_PROP_EVENT_VALUE_CLOSE      "close"
 #define AMEDIAMETRICS_PROP_EVENT_VALUE_CREATE     "create"
 #define AMEDIAMETRICS_PROP_EVENT_VALUE_CREATEAUDIOPATCH "createAudioPatch"
 #define AMEDIAMETRICS_PROP_EVENT_VALUE_CTOR       "ctor"
 #define AMEDIAMETRICS_PROP_EVENT_VALUE_DISCONNECT "disconnect"
 #define AMEDIAMETRICS_PROP_EVENT_VALUE_DTOR       "dtor"
+#define AMEDIAMETRICS_PROP_EVENT_VALUE_ENDAUDIOINTERVALGROUP "endAudioIntervalGroup"
 #define AMEDIAMETRICS_PROP_EVENT_VALUE_FLUSH      "flush"  // AudioTrack
 #define AMEDIAMETRICS_PROP_EVENT_VALUE_INVALIDATE "invalidate" // server track, record
 #define AMEDIAMETRICS_PROP_EVENT_VALUE_OPEN       "open"
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index 6afbd4f..0ed63a4 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -88,6 +88,7 @@
 #include "SpdifStreamOut.h"
 #include "AudioHwDevice.h"
 #include "NBAIO_Tee.h"
+#include "TrackMetrics.h"
 
 #include <powermanager/IPowerManager.h>
 
diff --git a/services/audioflinger/PlaybackTracks.h b/services/audioflinger/PlaybackTracks.h
index 1ff03c4..d8eebf3 100644
--- a/services/audioflinger/PlaybackTracks.h
+++ b/services/audioflinger/PlaybackTracks.h
@@ -171,6 +171,16 @@
 
             void    setTeePatches(TeePatches teePatches);
 
+    void tallyUnderrunFrames(size_t frames) override {
+       if (isOut()) { // we expect this from output tracks only
+           mAudioTrackServerProxy->tallyUnderrunFrames(frames);
+           // Fetch absolute numbers from AudioTrackShared as it counts
+           // contiguous underruns as a one -- we want a consistent number.
+           // TODO: isolate this counting into a class.
+           mTrackMetrics.logUnderruns(mAudioTrackServerProxy->getUnderrunCount(),
+                   mAudioTrackServerProxy->getUnderrunFrames());
+       }
+    }
 protected:
     // for numerous
     friend class PlaybackThread;
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 5d9c35a..69bf831 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -220,6 +220,9 @@
 {
     std::stringstream ss;
     for (size_t i = 0; i < patch->num_sinks; ++i) {
+        if (i > 0) {
+            ss << "|";
+        }
         ss << "(" << toString(patch->sinks[i].ext.device.type)
             << ", " << patch->sinks[i].ext.device.address << ")";
     }
@@ -230,6 +233,9 @@
 {
     std::stringstream ss;
     for (size_t i = 0; i < patch->num_sources; ++i) {
+        if (i > 0) {
+            ss << "|";
+        }
         ss << "(" << toString(patch->sources[i].ext.device.type)
             << ", " << patch->sources[i].ext.device.address << ")";
     }
@@ -1686,6 +1692,7 @@
 #ifdef TEE_SINK
     track->dumpTee(-1 /* fd */, "_REMOVE");
 #endif
+    track->logEndInterval(); // log to MediaMetrics
     return index;
 }
 
@@ -2553,6 +2560,7 @@
             chain->incActiveTrackCnt();
         }
 
+        track->logBeginInterval(patchSinksToString(&mPatch)); // log to MediaMetrics
         status = NO_ERROR;
     }
 
@@ -4256,10 +4264,16 @@
         status = mOutput->stream->setParameters(param.toString());
         *handle = AUDIO_PATCH_HANDLE_NONE;
     }
-    mediametrics::LogItem(mMetricsId)
-        .set(AMEDIAMETRICS_PROP_EVENT, AMEDIAMETRICS_PROP_EVENT_VALUE_CREATEAUDIOPATCH)
-        .set(AMEDIAMETRICS_PROP_OUTPUTDEVICES, patchSinksToString(patch).c_str())
+    const std::string patchSinksAsString = patchSinksToString(patch);
+    mediametrics::LogItem item(mMetricsId);
+    item.set(AMEDIAMETRICS_PROP_EVENT, AMEDIAMETRICS_PROP_EVENT_VALUE_CREATEAUDIOPATCH)
+        .set(AMEDIAMETRICS_PROP_OUTPUTDEVICES, patchSinksAsString.c_str())
         .record();
+    // also dispatch to active AudioTracks for MediaMetrics
+    for (const auto &track : mActiveTracks) {
+        track->logEndInterval();
+        track->logBeginInterval(patchSinksAsString);
+    }
 
     if (configChanged) {
         sendIoConfigEvent_l(AUDIO_OUTPUT_CONFIG_CHANGED);
@@ -4812,19 +4826,9 @@
             // because that is when the underrun occurs.
             // We do not distinguish between FastTracks and NormalTracks here.
             if (*mMixerStatus == MIXER_TRACKS_READY && mUnderrunFrames.size() > 0) {
-                mediametrics::LogItem item(mMetricsId);
-
-                item.set(AMEDIAMETRICS_PROP_EVENT, AMEDIAMETRICS_PROP_EVENT_VALUE_UNDERRUN);
                 for (const auto &underrun : mUnderrunFrames) {
-                    underrun.first->mAudioTrackServerProxy->tallyUnderrunFrames(
-                            underrun.second);
-
-                    item.set(std::string("[" AMEDIAMETRICS_KEY_PREFIX_AUDIO_TRACK)
-                            + std::to_string(underrun.first->portId())
-                            + "]" AMEDIAMETRICS_PROP_UNDERRUN,
-                            (int32_t)underrun.second);
+                    underrun.first->tallyUnderrunFrames(underrun.second);
                 }
-                item.record();
             }
         }
 
@@ -4837,7 +4841,7 @@
 
     private:
         const mixer_state * const mMixerStatus;
-        const std::string& mMetricsId;
+        const std::string& __unused mMetricsId;
         std::vector<std::pair<sp<Track>, size_t>> mUnderrunFrames;
     } deferredOperations(&mixerStatus, mMetricsId);
     // implicit nested scope for variable capture
@@ -7881,6 +7885,9 @@
             sendIoConfigEvent_l(
                 AUDIO_CLIENT_STARTED, recordTrack->creatorPid(), recordTrack->portId());
         }
+
+        recordTrack->logBeginInterval(patchSourcesToString(&mPatch)); // log to MediaMetrics
+
         // Catch up with current buffer indices if thread is already running.
         // This is what makes a new client discard all buffered data.  If the track's mRsmpInFront
         // was initialized to some value closer to the thread's mRsmpInFront, then the track could
@@ -8545,12 +8552,17 @@
         mPatch = *patch;
     }
 
-    mediametrics::LogItem(mMetricsId)
-        .set(AMEDIAMETRICS_PROP_EVENT, AMEDIAMETRICS_PROP_EVENT_VALUE_CREATEAUDIOPATCH)
-        .set(AMEDIAMETRICS_PROP_INPUTDEVICES, patchSourcesToString(patch).c_str())
+    const std::string pathSourcesAsString = patchSourcesToString(patch);
+    mediametrics::LogItem item(mMetricsId);
+    item.set(AMEDIAMETRICS_PROP_EVENT, AMEDIAMETRICS_PROP_EVENT_VALUE_CREATEAUDIOPATCH)
+        .set(AMEDIAMETRICS_PROP_INPUTDEVICES, pathSourcesAsString.c_str())
         .set(AMEDIAMETRICS_PROP_SOURCE, toString(mAudioSource).c_str())
         .record();
-
+    // also dispatch to active AudioRecords
+    for (const auto &track : mActiveTracks) {
+        track->logEndInterval();
+        track->logBeginInterval(pathSourcesAsString);
+    }
     return status;
 }
 
@@ -8861,6 +8873,7 @@
         chain->incActiveTrackCnt();
     }
 
+    track->logBeginInterval(patchSinksToString(&mPatch)); // log to MediaMetrics
     *handle = portId;
     broadcast_l();
 
@@ -8946,6 +8959,26 @@
     result = mHalStream->getBufferSize(&mBufferSize);
     LOG_ALWAYS_FATAL_IF(result != OK, "Error retrieving buffer size from HAL: %d", result);
     mFrameCount = mBufferSize / mFrameSize;
+
+    mediametrics::LogItem item(mMetricsId);
+    item.set(AMEDIAMETRICS_PROP_EVENT, AMEDIAMETRICS_PROP_EVENT_VALUE_READPARAMETERS)
+        .set(AMEDIAMETRICS_PROP_ENCODING, formatToString(mFormat).c_str())
+        .set(AMEDIAMETRICS_PROP_SAMPLERATE, (int32_t)mSampleRate)
+        .set(AMEDIAMETRICS_PROP_CHANNELMASK, (int32_t)mChannelMask)
+        .set(AMEDIAMETRICS_PROP_CHANNELCOUNT, (int32_t)mChannelCount)
+        .set(AMEDIAMETRICS_PROP_FRAMECOUNT, (int32_t)mFrameCount)
+        /*
+        .set(AMEDIAMETRICS_PROP_FLAGS, toString(flags).c_str())
+        .set(AMEDIAMETRICS_PROP_PREFIX_HAPTIC AMEDIAMETRICS_PROP_CHANNELMASK,
+                (int32_t)mHapticChannelMask)
+        .set(AMEDIAMETRICS_PROP_PREFIX_HAPTIC AMEDIAMETRICS_PROP_CHANNELCOUNT,
+                (int32_t)mHapticChannelCount)
+        */
+        .set(AMEDIAMETRICS_PROP_PREFIX_HAL    AMEDIAMETRICS_PROP_ENCODING,
+                formatToString(mHALFormat).c_str())
+        .set(AMEDIAMETRICS_PROP_PREFIX_HAL    AMEDIAMETRICS_PROP_FRAMECOUNT,
+                (int32_t)mFrameCount) // sic - added HAL
+        .record();
 }
 
 bool AudioFlinger::MmapThread::threadLoop()
diff --git a/services/audioflinger/TrackBase.h b/services/audioflinger/TrackBase.h
index e39b944..15c66fb 100644
--- a/services/audioflinger/TrackBase.h
+++ b/services/audioflinger/TrackBase.h
@@ -97,10 +97,7 @@
 
     virtual void        invalidate() {
                             if (mIsInvalid) return;
-                            mediametrics::LogItem(mMetricsId)
-                                .set(AMEDIAMETRICS_PROP_EVENT,
-                                     AMEDIAMETRICS_PROP_EVENT_VALUE_INVALIDATE)
-                                .record();
+                            mTrackMetrics.logInvalidate();
                             mIsInvalid = true;
                         }
             bool        isInvalid() const { return mIsInvalid; }
@@ -242,6 +239,20 @@
         }
     }
 
+    // Called by the PlaybackThread to indicate that the track is becoming active
+    // and a new interval should start with a given device list.
+    void logBeginInterval(const std::string& devices) {
+        mTrackMetrics.logBeginInterval(devices);
+    }
+
+    // Called by the PlaybackThread to indicate the track is no longer active.
+    void logEndInterval() {
+        mTrackMetrics.logEndInterval();
+    }
+
+    // Called to tally underrun frames in playback.
+    virtual void tallyUnderrunFrames(size_t /* frames */) {}
+
 protected:
     DISALLOW_COPY_AND_ASSIGN(TrackBase);
 
@@ -367,7 +378,7 @@
     int64_t             mLogStartTimeNs = 0;
     int64_t             mLogStartFrames = 0;
 
-    const std::string   mMetricsId;
+    TrackMetrics        mTrackMetrics;
 
     bool                mServerLatencySupported = false;
     std::atomic<bool>   mServerLatencyFromTrack{}; // latency from track or server timestamp.
diff --git a/services/audioflinger/TrackMetrics.h b/services/audioflinger/TrackMetrics.h
new file mode 100644
index 0000000..399c788
--- /dev/null
+++ b/services/audioflinger/TrackMetrics.h
@@ -0,0 +1,222 @@
+/*
+ * Copyright (C) 2020 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 ANDROID_AUDIO_TRACKMETRICS_H
+#define ANDROID_AUDIO_TRACKMETRICS_H
+
+#include <mutex>
+
+namespace android {
+
+/**
+ * TrackMetrics handles the AudioFlinger track metrics.
+ *
+ * We aggregate metrics for a particular device for proper analysis.
+ * This includes power, performance, and usage metrics.
+ *
+ * This class is thread-safe with a lock for safety.  There is no risk of deadlock
+ * as this class only executes external one-way calls in Mediametrics and does not
+ * call any other AudioFlinger class.
+ *
+ * Terminology:
+ * An AudioInterval is a contiguous playback segment.
+ * An AudioIntervalGroup is a group of continuous playback segments on the same device.
+ *
+ * We currently deliver metrics based on an AudioIntervalGroup.
+ */
+class TrackMetrics final {
+public:
+    TrackMetrics(std::string metricsId, bool isOut)
+        : mMetricsId(std::move(metricsId))
+        , mIsOut(isOut)
+        {}  // we don't log a constructor item, we wait for more info in logConstructor().
+
+    ~TrackMetrics() {
+        logEndInterval();
+        std::lock_guard l(mLock);
+        deliverCumulativeMetrics(AMEDIAMETRICS_PROP_EVENT_VALUE_ENDAUDIOINTERVALGROUP);
+        // we don't log a destructor item here.
+    }
+
+    // Called under the following circumstances
+    // 1) when we are added to the Thread
+    // 2) when we have a createPatch in the Thread.
+    void logBeginInterval(const std::string& devices) {
+        std::lock_guard l(mLock);
+        if (mDevices != devices) {
+            deliverCumulativeMetrics(AMEDIAMETRICS_PROP_EVENT_VALUE_ENDAUDIOINTERVALGROUP);
+            mDevices = devices;
+            resetIntervalGroupMetrics();
+            deliverDeviceMetrics(
+                    AMEDIAMETRICS_PROP_EVENT_VALUE_BEGINAUDIOINTERVALGROUP, devices.c_str());
+        }
+        ++mIntervalCount;
+        mIntervalStartTimeNs = systemTime();
+    }
+
+    void logConstructor(pid_t creatorPid, uid_t creatorUid) const {
+        // Once this item is logged by the server, the client can add properties.
+        // no lock required, all local or const variables.
+        mediametrics::LogItem(mMetricsId)
+            .setPid(creatorPid)
+            .setUid(creatorUid)
+            .set(AMEDIAMETRICS_PROP_ALLOWUID, (int32_t)creatorUid)
+            .set(AMEDIAMETRICS_PROP_EVENT,
+                    AMEDIAMETRICS_PROP_PREFIX_SERVER AMEDIAMETRICS_PROP_EVENT_VALUE_CTOR)
+            .record();
+    }
+
+    // Called when we are removed from the Thread.
+    void logEndInterval() {
+        std::lock_guard l(mLock);
+        if (mIntervalStartTimeNs != 0) {
+            const int64_t elapsedTimeNs = systemTime() - mIntervalStartTimeNs;
+            mIntervalStartTimeNs = 0;
+            mCumulativeTimeNs += elapsedTimeNs;
+            mDeviceTimeNs += elapsedTimeNs;
+        }
+    }
+
+    void logInvalidate() const {
+        // no lock required, all local or const variables.
+        mediametrics::LogItem(mMetricsId)
+            .set(AMEDIAMETRICS_PROP_EVENT,
+                 AMEDIAMETRICS_PROP_EVENT_VALUE_INVALIDATE)
+            .record();
+    }
+
+    void logLatencyAndStartup(double latencyMs, double startupMs) {
+        mediametrics::LogItem(mMetricsId)
+            .set(AMEDIAMETRICS_PROP_LATENCYMS, latencyMs)
+            .set(AMEDIAMETRICS_PROP_STARTUPMS, startupMs)
+            .record();
+        std::lock_guard l(mLock);
+        mDeviceLatencyMs.add(latencyMs);
+        mDeviceStartupMs.add(startupMs);
+    }
+
+    // may be called multiple times during an interval
+    void logVolume(float volume) {
+        const int64_t timeNs = systemTime();
+        std::lock_guard l(mLock);
+        if (mStartVolumeTimeNs == 0) {
+            mDeviceVolume = mVolume = volume;
+            mLastVolumeChangeTimeNs = mStartVolumeTimeNs = timeNs;
+            return;
+        }
+        mDeviceVolume = (mDeviceVolume * (mLastVolumeChangeTimeNs - mStartVolumeTimeNs) +
+            mVolume * (timeNs - mLastVolumeChangeTimeNs)) / (timeNs - mStartVolumeTimeNs);
+        mVolume = volume;
+        mLastVolumeChangeTimeNs = timeNs;
+    }
+
+    // Use absolute numbers returned by AudioTrackShared.
+    void logUnderruns(size_t count, size_t frames) {
+        std::lock_guard l(mLock);
+        mUnderrunCount = count;
+        mUnderrunFrames = frames;
+        // Consider delivering a message here (also be aware of excessive spam).
+    }
+
+private:
+    // no lock required - all arguments and constants.
+    void deliverDeviceMetrics(const char *eventName, const char *devices) const {
+        mediametrics::LogItem(mMetricsId)
+            .set(AMEDIAMETRICS_PROP_EVENT, eventName)
+            .set(mIsOut ? AMEDIAMETRICS_PROP_OUTPUTDEVICES
+                   : AMEDIAMETRICS_PROP_INPUTDEVICES, devices)
+           .record();
+    }
+
+    void deliverCumulativeMetrics(const char *eventName) const REQUIRES(mLock) {
+        if (mIntervalCount > 0) {
+            mediametrics::LogItem item(mMetricsId);
+            item.set(AMEDIAMETRICS_PROP_CUMULATIVETIMENS, mCumulativeTimeNs)
+                .set(AMEDIAMETRICS_PROP_DEVICETIMENS, mDeviceTimeNs)
+                .set(AMEDIAMETRICS_PROP_EVENT, eventName)
+                .set(AMEDIAMETRICS_PROP_INTERVALCOUNT, (int32_t)mIntervalCount);
+            if (mIsOut) {
+                item.set(AMEDIAMETRICS_PROP_DEVICEVOLUME, mDeviceVolume);
+            }
+            if (mDeviceLatencyMs.getN() > 0) {
+                item.set(AMEDIAMETRICS_PROP_DEVICELATENCYMS, mDeviceLatencyMs.getMean())
+                    .set(AMEDIAMETRICS_PROP_DEVICESTARTUPMS, mDeviceStartupMs.getMean());
+            }
+            if (mUnderrunCount > 0) {
+                item.set(AMEDIAMETRICS_PROP_UNDERRUN,
+                        (int32_t)(mUnderrunCount - mUnderrunCountSinceIntervalGroup))
+                    .set(AMEDIAMETRICS_PROP_UNDERRUNFRAMES,
+                        (int64_t)(mUnderrunFrames - mUnderrunFramesSinceIntervalGroup));
+            }
+            item.record();
+        }
+    }
+
+    void resetIntervalGroupMetrics() REQUIRES(mLock) {
+        // mDevices is not reset by resetIntervalGroupMetrics.
+
+        mIntervalCount = 0;
+        mIntervalStartTimeNs = 0;
+        // mCumulativeTimeNs is not reset by resetIntervalGroupMetrics.
+        mDeviceTimeNs = 0;
+
+        mVolume = 0.f;
+        mDeviceVolume = 0.f;
+        mStartVolumeTimeNs = 0;
+        mLastVolumeChangeTimeNs = 0;
+
+        mDeviceLatencyMs.reset();
+        mDeviceStartupMs.reset();
+
+        mUnderrunCountSinceIntervalGroup = mUnderrunCount;
+        mUnderrunFramesSinceIntervalGroup = mUnderrunFrames;
+        // do not reset mUnderrunCount - it keeps continuously running for tracks.
+    }
+
+    const std::string mMetricsId;
+    const bool        mIsOut;  // if true, than a playback track, otherwise used for record.
+
+    mutable           std::mutex mLock;
+
+    // Devices in the interval group.
+    std::string       mDevices GUARDED_BY(mLock);
+
+    // Number of intervals and playing time
+    int32_t           mIntervalCount GUARDED_BY(mLock) = 0;
+    int64_t           mIntervalStartTimeNs GUARDED_BY(mLock) = 0;
+    int64_t           mCumulativeTimeNs GUARDED_BY(mLock) = 0;
+    int64_t           mDeviceTimeNs GUARDED_BY(mLock) = 0;
+
+    // Average volume
+    double            mVolume GUARDED_BY(mLock) = 0.f;
+    double            mDeviceVolume GUARDED_BY(mLock) = 0.f;
+    int64_t           mStartVolumeTimeNs GUARDED_BY(mLock) = 0;
+    int64_t           mLastVolumeChangeTimeNs GUARDED_BY(mLock) = 0;
+
+    // latency and startup for each interval.
+    audio_utils::Statistics<double> mDeviceLatencyMs GUARDED_BY(mLock);
+    audio_utils::Statistics<double> mDeviceStartupMs GUARDED_BY(mLock);
+
+    // underrun count and frames
+    int64_t           mUnderrunCount GUARDED_BY(mLock) = 0;
+    int64_t           mUnderrunFrames GUARDED_BY(mLock) = 0;
+    int64_t           mUnderrunCountSinceIntervalGroup GUARDED_BY(mLock) = 0;
+    int64_t           mUnderrunFramesSinceIntervalGroup GUARDED_BY(mLock) = 0;
+};
+
+} // namespace android
+
+#endif // ANDROID_AUDIO_TRACKMETRICS_H
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index 4898d37..58c61c9 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -106,7 +106,7 @@
         mThreadIoHandle(thread ? thread->id() : AUDIO_IO_HANDLE_NONE),
         mPortId(portId),
         mIsInvalid(false),
-        mMetricsId(std::move(metricsId)),
+        mTrackMetrics(std::move(metricsId), isOut),
         mCreatorPid(creatorPid)
 {
     const uid_t callingUid = IPCThreadState::self()->getCallingUid();
@@ -602,13 +602,7 @@
     }
 
     // Once this item is logged by the server, the client can add properties.
-    mediametrics::LogItem(mMetricsId)
-        .setPid(creatorPid)
-        .setUid(uid)
-        .set(AMEDIAMETRICS_PROP_ALLOWUID, (int32_t)uid)
-        .set(AMEDIAMETRICS_PROP_EVENT,
-                AMEDIAMETRICS_PROP_PREFIX_SERVER AMEDIAMETRICS_PROP_EVENT_VALUE_CTOR)
-        .record();
+    mTrackMetrics.logConstructor(creatorPid, uid);
 }
 
 AudioFlinger::PlaybackThread::Track::~Track()
@@ -1249,6 +1243,7 @@
     if (mFinalVolume != volume) { // Compare to an epsilon if too many meaningless updates
         mFinalVolume = volume;
         setMetadataHasChanged();
+        mTrackMetrics.logVolume(volume);
     }
 }
 
@@ -1534,10 +1529,7 @@
                     (long long)mLogStartTimeNs,
                     (long long)local.mPosition[ExtendedTimestamp::LOCATION_SERVER],
                     (long long)mLogStartFrames);
-            mediametrics::LogItem(mMetricsId)
-                .set(AMEDIAMETRICS_PROP_LATENCYMS, latencyMs)
-                .set(AMEDIAMETRICS_PROP_STARTUPMS, startUpMs)
-                .record();
+            mTrackMetrics.logLatencyAndStartup(latencyMs, startUpMs);
         }
     }
 }
@@ -2163,12 +2155,7 @@
 #endif
 
     // Once this item is logged by the server, the client can add properties.
-    mediametrics::LogItem(mMetricsId)
-        .setPid(creatorPid)
-        .setUid(uid)
-        .set(AMEDIAMETRICS_PROP_ALLOWUID, (int32_t)uid)
-        .set(AMEDIAMETRICS_PROP_EVENT, "server." AMEDIAMETRICS_PROP_EVENT_VALUE_CTOR)
-        .record();
+    mTrackMetrics.logConstructor(creatorPid, uid);
 }
 
 AudioFlinger::RecordThread::RecordTrack::~RecordTrack()
@@ -2725,9 +2712,12 @@
                   nullptr /* buffer */, (size_t)0 /* bufferSize */,
                   sessionId, creatorPid, uid, isOut,
                   ALLOC_NONE,
-                  TYPE_DEFAULT, portId),
+                  TYPE_DEFAULT, portId,
+                  std::string(AMEDIAMETRICS_KEY_PREFIX_AUDIO_MMAP) + std::to_string(portId)),
         mPid(pid), mSilenced(false), mSilencedNotified(false)
 {
+    // Once this item is logged by the server, the client can add properties.
+    mTrackMetrics.logConstructor(creatorPid, uid);
 }
 
 AudioFlinger::MmapThread::MmapTrack::~MmapTrack()