diff --git a/avisynth_filter/src/frame_handler.cpp b/avisynth_filter/src/frame_handler.cpp
index 554fb97..d8e5eff 100644
--- a/avisynth_filter/src/frame_handler.cpp
+++ b/avisynth_filter/src/frame_handler.cpp
@@ -149,15 +149,7 @@ auto FrameHandler::BeginFlush() -> void {
 auto FrameHandler::EndFlush(const std::function<void ()> &interim) -> void {
     Environment::GetInstance().Log(L"FrameHandler start EndFlush()");
 
-    /*
-     * EndFlush() can be called by either the application or the worker thread
-     *
-     * when called by former, we need to synchronize with the worker thread
-     * when called by latter, current thread ID should be same as the worker thread, and no need for sync
-     */
-    if (std::this_thread::get_id() != _workerThread.get_id()) {
-        _isWorkerLatched.wait(false);
-    }
+    _isWorkerLatched.wait(false);
 
     if (interim) {
         interim();
@@ -207,16 +199,6 @@ auto FrameHandler::ResetInput() -> void {
     _currentInputFrameRate = 0;
 }
 
-auto FrameHandler::ResetOutput() -> void {
-    // to ensure these non-atomic properties are only modified by their sole consumer the worker thread
-    ASSERT(std::this_thread::get_id() == _workerThread.get_id());
-
-    _nextOutputFrameNb = 0;
-
-    _frameRateCheckpointOutputFrameNb = 0;
-    _currentOutputFrameRate = 0;
-}
-
 auto FrameHandler::PrepareOutputSample(ATL::CComPtr<IMediaSample> &sample, REFERENCE_TIME startTime, REFERENCE_TIME stopTime) -> bool {
     if (FAILED(_filter.m_pOutput->GetDeliveryBuffer(&sample, &startTime, &stopTime, 0))) {
         // avoid releasing the invalid pointer in case the function change it to some random invalid address
@@ -266,6 +248,13 @@ auto FrameHandler::PrepareOutputSample(ATL::CComPtr<IMediaSample> &sample, REFER
 }
 
 auto FrameHandler::WorkerProc() -> void {
+    const auto ResetOutput = [this]() -> void {
+        _nextOutputFrameNb = 0;
+
+        _frameRateCheckpointOutputFrameNb = 0;
+        _currentOutputFrameRate = 0;
+    };
+
     Environment::GetInstance().Log(L"Start worker thread");
 
 #ifdef _DEBUG
diff --git a/avisynth_filter/src/frame_handler.h b/avisynth_filter/src/frame_handler.h
index acb9d1d..31f0a13 100644
--- a/avisynth_filter/src/frame_handler.h
+++ b/avisynth_filter/src/frame_handler.h
@@ -40,7 +40,6 @@ class FrameHandler {
                                           int &currentFrameRate) -> void;
 
     auto ResetInput() -> void;
-    auto ResetOutput() -> void;
     auto PrepareOutputSample(ATL::CComPtr<IMediaSample> &sample, REFERENCE_TIME startTime, REFERENCE_TIME stopTime) -> bool;
     auto WorkerProc() -> void;
     auto GarbageCollect(int srcFrameNb) -> void;
diff --git a/vapoursynth_filter/src/frame_handler.cpp b/vapoursynth_filter/src/frame_handler.cpp
index 6992155..a7c4cc8 100644
--- a/vapoursynth_filter/src/frame_handler.cpp
+++ b/vapoursynth_filter/src/frame_handler.cpp
@@ -203,15 +203,7 @@ auto FrameHandler::BeginFlush() -> void {
 auto FrameHandler::EndFlush(const std::function<void ()> &interim) -> void {
     Environment::GetInstance().Log(L"FrameHandler start EndFlush()");
 
-    /*
-     * EndFlush() can be called by either the application or the worker thread
-     *
-     * when called by former, we need to synchronize with the worker thread
-     * when called by latter, current thread ID should be same as the worker thread, and no need for sync
-     */
-    if (std::this_thread::get_id() != _workerThread.get_id()) {
-        _isWorkerLatched.wait(false);
-    }
+    _isWorkerLatched.wait(false);
 
     {
         std::shared_lock sharedOutputLock(_outputMutex);
@@ -311,18 +303,6 @@ auto FrameHandler::ResetInput() -> void {
 
     _frameRateCheckpointInputSampleNb = 0;
     _currentInputFrameRate = 0;
-
-    _frameRateCheckpointOutputFrameNb = 0;
-    _currentOutputFrameRate = 0;
-}
-
-auto FrameHandler::ResetOutput() -> void {
-    // to ensure these non-atomic properties are only modified by their sole consumer the worker thread
-    const std::thread::id actual = std::this_thread::get_id();
-    const std::thread::id expected = _workerThread.get_id();
-    ASSERT(actual == expected);
-
-    _nextDeliveryFrameNb = 0;
 }
 
 auto FrameHandler::PrepareOutputSample(ATL::CComPtr<IMediaSample> &sample, int frameNb, OutputFrameData &data) -> bool {
@@ -393,6 +373,13 @@ auto FrameHandler::PrepareOutputSample(ATL::CComPtr<IMediaSample> &sample, int f
 }
 
 auto FrameHandler::WorkerProc() -> void {
+    const auto ResetOutput = [this]() -> void {
+        _nextDeliveryFrameNb = 0;
+
+        _frameRateCheckpointOutputFrameNb = 0;
+        _currentOutputFrameRate = 0;
+    };
+
     Environment::GetInstance().Log(L"Start worker thread");
 
 #ifdef _DEBUG
diff --git a/vapoursynth_filter/src/frame_handler.h b/vapoursynth_filter/src/frame_handler.h
index f6ec812..71343e4 100644
--- a/vapoursynth_filter/src/frame_handler.h
+++ b/vapoursynth_filter/src/frame_handler.h
@@ -51,7 +51,6 @@ class FrameHandler {
                                           int &currentFrameRate) -> void;
 
     auto ResetInput() -> void;
-    auto ResetOutput() -> void;
     auto PrepareOutputSample(ATL::CComPtr<IMediaSample> &sample, int frameNb, OutputFrameData &data) -> bool;
     auto WorkerProc() -> void;
     auto GarbageCollect(int srcFrameNb) -> void;