diff --git a/services/mediatranscoding/Android.bp b/services/mediatranscoding/Android.bp
index 79e9fbc..498ce09 100644
--- a/services/mediatranscoding/Android.bp
+++ b/services/mediatranscoding/Android.bp
@@ -14,7 +14,7 @@
         "libmediatranscoding",
         "libutils",
     ],
-    
+
     export_shared_lib_headers: [
         "libmediatranscoding",
     ],
diff --git a/services/mediatranscoding/SimulatedTranscoder.cpp b/services/mediatranscoding/SimulatedTranscoder.cpp
index 0a77fbe..380d757 100644
--- a/services/mediatranscoding/SimulatedTranscoder.cpp
+++ b/services/mediatranscoding/SimulatedTranscoder.cpp
@@ -54,27 +54,43 @@
     }
     ALOGV("%s: job {%d}: processingTime: %lld", __FUNCTION__, jobId,
           (long long)mJobProcessingTimeMs);
-    queueEvent(Event::Start, clientId, jobId);
+    queueEvent(Event::Start, clientId, jobId, [=] {
+        auto callback = mCallback.lock();
+        if (callback != nullptr) {
+            callback->onStarted(clientId, jobId);
+        }
+    });
 }
 
 void SimulatedTranscoder::pause(ClientIdType clientId, JobIdType jobId) {
-    queueEvent(Event::Pause, clientId, jobId);
+    queueEvent(Event::Pause, clientId, jobId, [=] {
+        auto callback = mCallback.lock();
+        if (callback != nullptr) {
+            callback->onPaused(clientId, jobId);
+        }
+    });
 }
 
 void SimulatedTranscoder::resume(ClientIdType clientId, JobIdType jobId) {
-    queueEvent(Event::Resume, clientId, jobId);
+    queueEvent(Event::Resume, clientId, jobId, [=] {
+        auto callback = mCallback.lock();
+        if (callback != nullptr) {
+            callback->onResumed(clientId, jobId);
+        }
+    });
 }
 
 void SimulatedTranscoder::stop(ClientIdType clientId, JobIdType jobId) {
-    queueEvent(Event::Stop, clientId, jobId);
+    queueEvent(Event::Stop, clientId, jobId, nullptr);
 }
 
-void SimulatedTranscoder::queueEvent(Event::Type type, ClientIdType clientId, JobIdType jobId) {
+void SimulatedTranscoder::queueEvent(Event::Type type, ClientIdType clientId, JobIdType jobId,
+                                     std::function<void()> runnable) {
     ALOGV("%s: job {%lld, %d}: %s", __FUNCTION__, (long long)clientId, jobId, toString(type));
 
     auto lock = std::scoped_lock(mLock);
 
-    mQueue.push_back({type, clientId, jobId});
+    mQueue.push_back({type, clientId, jobId, runnable});
     mCondition.notify_one();
 }
 
@@ -139,10 +155,9 @@
                 continue;
             }
 
-            auto callback = mCallback.lock();
-            if (callback != nullptr) {
+            if (event.runnable != nullptr) {
                 lock.unlock();
-                callback->onProgressUpdate(event.clientId, event.jobId, event.type);
+                event.runnable();
                 lock.lock();
             }
         }
diff --git a/services/mediatranscoding/SimulatedTranscoder.h b/services/mediatranscoding/SimulatedTranscoder.h
index 9054b4c..0eb74c8 100644
--- a/services/mediatranscoding/SimulatedTranscoder.h
+++ b/services/mediatranscoding/SimulatedTranscoder.h
@@ -42,6 +42,7 @@
         enum Type { NoEvent, Start, Pause, Resume, Stop, Finished, Failed } type;
         ClientIdType clientId;
         JobIdType jobId;
+        std::function<void()> runnable;
     };
 
     static constexpr int64_t kJobDurationUs = 1000000;
@@ -67,7 +68,8 @@
     int64_t mJobProcessingTimeMs = kJobDurationUs / 1000;
 
     static const char* toString(Event::Type type);
-    void queueEvent(Event::Type type, ClientIdType clientId, JobIdType jobId);
+    void queueEvent(Event::Type type, ClientIdType clientId, JobIdType jobId,
+                    std::function<void()> runnable);
     void threadLoop();
 };
 
diff --git a/services/mediatranscoding/tests/mediatranscodingservice_tests.cpp b/services/mediatranscoding/tests/mediatranscodingservice_tests.cpp
index dfe105d..3bc7b15 100644
--- a/services/mediatranscoding/tests/mediatranscodingservice_tests.cpp
+++ b/services/mediatranscoding/tests/mediatranscodingservice_tests.cpp
@@ -216,11 +216,20 @@
         return Status::ok();
     }
 
-    Status onTranscodingStarted(int32_t /*in_jobId*/) override { return Status::ok(); }
+    Status onTranscodingStarted(int32_t in_jobId) override {
+        append(Start(mClientId, in_jobId));
+        return Status::ok();
+    }
 
-    Status onTranscodingPaused(int32_t /*in_jobId*/) override { return Status::ok(); }
+    Status onTranscodingPaused(int32_t in_jobId) override {
+        append(Pause(mClientId, in_jobId));
+        return Status::ok();
+    }
 
-    Status onTranscodingResumed(int32_t /*in_jobId*/) override { return Status::ok(); }
+    Status onTranscodingResumed(int32_t in_jobId) override {
+        append(Resume(mClientId, in_jobId));
+        return Status::ok();
+    }
 
     Status onTranscodingFinished(
             int32_t in_jobId,
@@ -241,23 +250,7 @@
         return Status::ok();
     }
 
-    Status onProgressUpdate(int32_t in_jobId, int32_t in_progress) override {
-        // The progress numbers from the SimulatedTranscoder represents the
-        // event's type in the transcoder.
-        switch (in_progress) {
-        case SimulatedTranscoder::Event::Start:
-            append(EventTracker::Start(mClientId, in_jobId));
-            break;
-        case SimulatedTranscoder::Event::Pause:
-            append(EventTracker::Pause(mClientId, in_jobId));
-            break;
-        case SimulatedTranscoder::Event::Resume:
-            append(EventTracker::Resume(mClientId, in_jobId));
-            break;
-        default:
-            ALOGE("unrecognized progress number %d, ignored by test", in_progress);
-            break;
-        }
+    Status onProgressUpdate(int32_t /*in_jobId*/, int32_t /*in_progress*/) override {
         return Status::ok();
     }
 
@@ -393,8 +386,9 @@
         }
 
         return status.isOk() && (result == shouldSucceed) &&
-               (!shouldSucceed || (job.jobId == jobId && 
-                job.request.sourceFilePath == sourceFilePath && job.request.destinationFilePath == destinationFilePath));
+               (!shouldSucceed ||
+                (job.jobId == jobId && job.request.sourceFilePath == sourceFilePath &&
+                 job.request.destinationFilePath == destinationFilePath));
     }
 
     std::shared_ptr<IMediaTranscodingService> mService;
@@ -592,8 +586,10 @@
     registerMultipleClients();
 
     // Submit some offline jobs first.
-    EXPECT_TRUE(submit(mClient1, 0, "test_source_file_0", "test_destination_file_0", TranscodingJobPriority::kUnspecified));
-    EXPECT_TRUE(submit(mClient1, 1, "test_source_file_1", "test_destination_file_1", TranscodingJobPriority::kUnspecified));
+    EXPECT_TRUE(submit(mClient1, 0, "test_source_file_0", "test_destination_file_0",
+                       TranscodingJobPriority::kUnspecified));
+    EXPECT_TRUE(submit(mClient1, 1, "test_source_file_1", "test_destination_file_1",
+                       TranscodingJobPriority::kUnspecified));
 
     // Job 0 should start immediately.
     EXPECT_EQ(mClientCallback1->pop(kPaddingUs), EventTracker::Start(CLIENT(1), 0));