diff --git a/media/libnblog/Merger.cpp b/media/libnblog/Merger.cpp
new file mode 100644
index 0000000..5f6e0d1
--- /dev/null
+++ b/media/libnblog/Merger.cpp
@@ -0,0 +1,297 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+#define LOG_TAG "NBLog"
+//#define LOG_NDEBUG 0
+
+#include <memory>
+#include <queue>
+#include <stddef.h>
+#include <stdint.h>
+#include <vector>
+
+#include <audio_utils/fifo.h>
+#include <json/json.h>
+#include <media/nblog/Merger.h>
+#include <media/nblog/PerformanceAnalysis.h>
+#include <media/nblog/ReportPerformance.h>
+#include <media/nblog/Reader.h>
+#include <media/nblog/Timeline.h>
+#include <utils/Condition.h>
+#include <utils/Log.h>
+#include <utils/Mutex.h>
+#include <utils/RefBase.h>
+#include <utils/String8.h>
+#include <utils/Timers.h>
+#include <utils/Thread.h>
+
+namespace android {
+namespace NBLog {
+
+Merger::Merger(const void *shared, size_t size):
+      mShared((Shared *) shared),
+      mFifo(mShared != NULL ?
+        new audio_utils_fifo(size, sizeof(uint8_t),
+            mShared->mBuffer, mShared->mRear, NULL /*throttlesFront*/) : NULL),
+      mFifoWriter(mFifo != NULL ? new audio_utils_fifo_writer(*mFifo) : NULL)
+{
+}
+
+void Merger::addReader(const sp<Reader> &reader)
+{
+    // FIXME This is called by binder thread in MediaLogService::registerWriter
+    //       but the access to shared variable mReaders is not yet protected by a lock.
+    mReaders.push_back(reader);
+}
+
+// items placed in priority queue during merge
+// composed by a timestamp and the index of the snapshot where the timestamp came from
+struct MergeItem
+{
+    int64_t ts;
+    int index;
+    MergeItem(int64_t ts, int index): ts(ts), index(index) {}
+};
+
+bool operator>(const struct MergeItem &i1, const struct MergeItem &i2)
+{
+    return i1.ts > i2.ts || (i1.ts == i2.ts && i1.index > i2.index);
+}
+
+// Merge registered readers, sorted by timestamp, and write data to a single FIFO in local memory
+void Merger::merge()
+{
+    if (true) return; // Merging is not necessary at the moment, so this is to disable it
+                      // and bypass compiler warnings about member variables not being used.
+    const int nLogs = mReaders.size();
+    std::vector<std::unique_ptr<Snapshot>> snapshots(nLogs);
+    std::vector<EntryIterator> offsets;
+    offsets.reserve(nLogs);
+    for (int i = 0; i < nLogs; ++i) {
+        snapshots[i] = mReaders[i]->getSnapshot();
+        offsets.push_back(snapshots[i]->begin());
+    }
+    // initialize offsets
+    // TODO custom heap implementation could allow to update top, improving performance
+    // for bursty buffers
+    std::priority_queue<MergeItem, std::vector<MergeItem>, std::greater<MergeItem>> timestamps;
+    for (int i = 0; i < nLogs; ++i)
+    {
+        if (offsets[i] != snapshots[i]->end()) {
+            std::unique_ptr<AbstractEntry> abstractEntry = AbstractEntry::buildEntry(offsets[i]);
+            if (abstractEntry == nullptr) {
+                continue;
+            }
+            timestamps.emplace(abstractEntry->timestamp(), i);
+        }
+    }
+
+    while (!timestamps.empty()) {
+        int index = timestamps.top().index;     // find minimum timestamp
+        // copy it to the log, increasing offset
+        offsets[index] = AbstractEntry::buildEntry(offsets[index])->
+            copyWithAuthor(mFifoWriter, index);
+        // update data structures
+        timestamps.pop();
+        if (offsets[index] != snapshots[index]->end()) {
+            int64_t ts = AbstractEntry::buildEntry(offsets[index])->timestamp();
+            timestamps.emplace(ts, index);
+        }
+    }
+}
+
+const std::vector<sp<Reader>>& Merger::getReaders() const
+{
+    //AutoMutex _l(mLock);
+    return mReaders;
+}
+
+// ---------------------------------------------------------------------------
+
+MergeReader::MergeReader(const void *shared, size_t size, Merger &merger)
+    : Reader(shared, size, "MergeReader"), mReaders(merger.getReaders())
+{
+}
+
+// Takes raw content of the local merger FIFO, processes log entries, and
+// writes the data to a map of class PerformanceAnalysis, based on their thread ID.
+void MergeReader::processSnapshot(Snapshot &snapshot, int author)
+{
+    ReportPerformance::PerformanceData& data = mThreadPerformanceData[author];
+    // We don't do "auto it" because it reduces readability in this case.
+    for (EntryIterator it = snapshot.begin(); it != snapshot.end(); ++it) {
+        switch (it->type) {
+        case EVENT_HISTOGRAM_ENTRY_TS: {
+            const HistTsEntry payload = it.payload<HistTsEntry>();
+            // TODO: hash for histogram ts and audio state need to match
+            // and correspond to audio production source file location
+            mThreadPerformanceAnalysis[author][0 /*hash*/].logTsEntry(payload.ts);
+        } break;
+        case EVENT_AUDIO_STATE: {
+            mThreadPerformanceAnalysis[author][0 /*hash*/].handleStateChange();
+        } break;
+        case EVENT_THREAD_INFO: {
+            const thread_info_t info = it.payload<thread_info_t>();
+            // TODO make PerformanceData hold a type of thread_info_t.
+            // Currently, thread_info_t is defined in NBLog.h, which includes
+            // PerformanceAnalysis.h. PerformanceData is defined in PerformanceAnalysis.h,
+            // where including NBLog.h would result in circular includes. The organization
+            // of files will need to change to avoid this problem.
+            data.threadInfo = info;
+        } break;
+        case EVENT_LATENCY: {
+            const double latencyMs = it.payload<double>();
+            data.latencyHist.add(latencyMs);
+        } break;
+        case EVENT_WORK_TIME: {
+            const int64_t monotonicNs = it.payload<int64_t>();
+            const double monotonicMs = monotonicNs * 1e-6;
+            data.workHist.add(monotonicMs);
+            data.active += monotonicNs;
+        } break;
+        case EVENT_WARMUP_TIME: {
+            const double timeMs = it.payload<double>();
+            data.warmupHist.add(timeMs);
+        } break;
+        case EVENT_UNDERRUN:
+            data.underruns++;
+            break;
+        case EVENT_OVERRUN:
+            data.overruns++;
+            break;
+        case EVENT_RESERVED:
+        case EVENT_UPPER_BOUND:
+            ALOGW("warning: unexpected event %d", it->type);
+        default:
+            break;
+        }
+    }
+}
+
+void MergeReader::getAndProcessSnapshot()
+{
+    // get a snapshot of each reader and process them
+    // TODO insert lock here
+    const size_t nLogs = mReaders.size();
+    std::vector<std::unique_ptr<Snapshot>> snapshots(nLogs);
+    for (size_t i = 0; i < nLogs; i++) {
+        snapshots[i] = mReaders[i]->getSnapshot();
+    }
+    // TODO unlock lock here
+    for (size_t i = 0; i < nLogs; i++) {
+        if (snapshots[i] != nullptr) {
+            processSnapshot(*(snapshots[i]), i);
+        }
+    }
+    checkPushToMediaMetrics();
+}
+
+void MergeReader::checkPushToMediaMetrics()
+{
+    const nsecs_t now = systemTime();
+    for (auto& item : mThreadPerformanceData) {
+        ReportPerformance::PerformanceData& data = item.second;
+        if (now - data.start >= kPeriodicMediaMetricsPush) {
+            (void)ReportPerformance::sendToMediaMetrics(data);
+            data.reset();   // data is persistent per thread
+        }
+    }
+}
+
+void MergeReader::dump(int fd, int indent)
+{
+    // TODO: add a mutex around media.log dump
+    ReportPerformance::dump(fd, indent, mThreadPerformanceAnalysis);
+    Json::Value root(Json::arrayValue);
+    for (const auto& item : mThreadPerformanceData) {
+        const ReportPerformance::PerformanceData& data = item.second;
+        std::unique_ptr<Json::Value> threadData = ReportPerformance::dumpToJson(data);
+        if (threadData == nullptr) {
+            continue;
+        }
+        (*threadData)["threadNum"] = item.first;
+        root.append(*threadData);
+    }
+    Json::StyledWriter writer;
+    std::string rootStr = writer.write(root);
+    write(fd, rootStr.c_str(), rootStr.size());
+}
+
+void MergeReader::handleAuthor(const AbstractEntry &entry, String8 *body)
+{
+    int author = entry.author();
+    if (author == -1) {
+        return;
+    }
+    // FIXME Needs a lock
+    const char* name = mReaders[author]->name().c_str();
+    body->appendFormat("%s: ", name);
+}
+
+// ---------------------------------------------------------------------------
+
+MergeThread::MergeThread(Merger &merger, MergeReader &mergeReader)
+    : mMerger(merger),
+      mMergeReader(mergeReader),
+      mTimeoutUs(0)
+{
+}
+
+MergeThread::~MergeThread()
+{
+    // set exit flag, set timeout to 0 to force threadLoop to exit and wait for the thread to join
+    requestExit();
+    setTimeoutUs(0);
+    join();
+}
+
+bool MergeThread::threadLoop()
+{
+    bool doMerge;
+    {
+        AutoMutex _l(mMutex);
+        // If mTimeoutUs is negative, wait on the condition variable until it's positive.
+        // If it's positive, merge. The minimum period between waking the condition variable
+        // is handled in AudioFlinger::MediaLogNotifier::threadLoop().
+        mCond.wait(mMutex);
+        doMerge = mTimeoutUs > 0;
+        mTimeoutUs -= kThreadSleepPeriodUs;
+    }
+    if (doMerge) {
+        // Merge data from all the readers
+        mMerger.merge();
+        // Process the data collected by mMerger and write it to PerformanceAnalysis
+        // FIXME: decide whether to call getAndProcessSnapshot every time
+        // or whether to have a separate thread that calls it with a lower frequency
+        mMergeReader.getAndProcessSnapshot();
+    }
+    return true;
+}
+
+void MergeThread::wakeup()
+{
+    setTimeoutUs(kThreadWakeupPeriodUs);
+}
+
+void MergeThread::setTimeoutUs(int time)
+{
+    AutoMutex _l(mMutex);
+    mTimeoutUs = time;
+    mCond.signal();
+}
+
+}   // namespace NBLog
+}   // namespace android