diff --git a/apps/LoopThroughWithOpenGLCompositing/videoio/VideoPlayoutScheduler.cpp b/apps/LoopThroughWithOpenGLCompositing/videoio/VideoPlayoutScheduler.cpp
index c0480b3..750e301 100644
--- a/apps/LoopThroughWithOpenGLCompositing/videoio/VideoPlayoutScheduler.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/VideoPlayoutScheduler.cpp
@@ -32,6 +32,17 @@ VideoIOScheduleTime VideoPlayoutScheduler::NextScheduleTime()
 	return time;
 }
 
+void VideoPlayoutScheduler::AlignNextScheduleTimeToPlayback(int64_t streamTime, uint64_t leadFrames)
+{
+	if (mFrameDuration <= 0 || streamTime < 0)
+		return;
+
+	const uint64_t playbackFrameIndex = static_cast<uint64_t>(streamTime / mFrameDuration);
+	const uint64_t minimumScheduleIndex = playbackFrameIndex + leadFrames;
+	if (minimumScheduleIndex > mScheduledFrameIndex)
+		mScheduledFrameIndex = minimumScheduleIndex;
+}
+
 VideoPlayoutRecoveryDecision VideoPlayoutScheduler::AccountForCompletionResult(VideoIOCompletionResult result, uint64_t readyQueueDepth)
 {
 	++mCompletedFrameIndex;
diff --git a/apps/LoopThroughWithOpenGLCompositing/videoio/VideoPlayoutScheduler.h b/apps/LoopThroughWithOpenGLCompositing/videoio/VideoPlayoutScheduler.h
index d55aa1d..8635899 100644
--- a/apps/LoopThroughWithOpenGLCompositing/videoio/VideoPlayoutScheduler.h
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/VideoPlayoutScheduler.h
@@ -12,6 +12,7 @@ public:
 	void Configure(int64_t frameDuration, int64_t timeScale, const VideoPlayoutPolicy& policy);
 	void Reset();
 	VideoIOScheduleTime NextScheduleTime();
+	void AlignNextScheduleTimeToPlayback(int64_t streamTime, uint64_t leadFrames);
 	VideoPlayoutRecoveryDecision AccountForCompletionResult(VideoIOCompletionResult result, uint64_t readyQueueDepth = 0);
 	double FrameBudgetMilliseconds() const;
 	uint64_t ScheduledFrameIndex() const { return mScheduledFrameIndex; }
diff --git a/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.cpp b/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.cpp
index 047c359..dd5c446 100644
--- a/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.cpp
@@ -526,13 +526,24 @@ bool DeckLinkSession::PopulateOutputFrame(IDeckLinkMutableVideoFrame* outputVide
 
 bool DeckLinkSession::ScheduleFrame(IDeckLinkMutableVideoFrame* outputVideoFrame)
 {
-	const VideoIOScheduleTime scheduleTime = mScheduler.NextScheduleTime();
 	if (outputVideoFrame == nullptr || output == nullptr)
 	{
 		++mState.deckLinkScheduleFailureCount;
 		return false;
 	}
 
+	BMDTimeValue streamTime = 0;
+	double playbackSpeed = 0.0;
+	if (output->GetScheduledStreamTime(mScheduler.TimeScale(), &streamTime, &playbackSpeed) == S_OK && playbackSpeed > 0.0)
+	{
+		RefreshBufferedVideoFrameCount();
+		const uint64_t leadFrames = mState.actualDeckLinkBufferedFramesAvailable
+			? static_cast<uint64_t>(mState.actualDeckLinkBufferedFrames) + 1
+			: static_cast<uint64_t>(mPlayoutPolicy.targetPrerollFrames);
+		mScheduler.AlignNextScheduleTimeToPlayback(streamTime, leadFrames);
+	}
+
+	const VideoIOScheduleTime scheduleTime = mScheduler.NextScheduleTime();
 	const auto scheduleStart = std::chrono::steady_clock::now();
 	const HRESULT result = output->ScheduleVideoFrame(outputVideoFrame, scheduleTime.streamTime, scheduleTime.duration, scheduleTime.timeScale);
 	const auto scheduleEnd = std::chrono::steady_clock::now();
diff --git a/apps/RenderCadenceCompositor/README.md b/apps/RenderCadenceCompositor/README.md
index 62cb559..ff1a16e 100644
--- a/apps/RenderCadenceCompositor/README.md
+++ b/apps/RenderCadenceCompositor/README.md
@@ -11,14 +11,14 @@ Before adding features here, read the guardrails in [Render Cadence Golden Rules
 ```text
 RenderThread
   owns a hidden OpenGL context
-  polls latest input frames without waiting
+  polls the oldest ready input frame without waiting
   uploads input frames into a render-owned GL texture
   renders simple BGRA8 motion at selected cadence
   queues async PBO readback
   publishes completed frames into SystemFrameExchange
 
 InputFrameMailbox
-  owns latest disposable CPU input slots
+  owns bounded FIFO CPU input slots
   keeps a bounded three-ready-frame input buffer for render
   trims frames beyond that bound to avoid runaway input latency
   protects the one frame currently being uploaded by render
@@ -26,7 +26,7 @@ InputFrameMailbox
 
 SystemFrameExchange
   owns Free / Rendering / Completed / Scheduled slots
-  drops old completed unscheduled frames when render needs space
+  preserves completed output frames once they are waiting for playout
   protects scheduled frames until DeckLink completion
 
 DeckLinkOutputThread
@@ -286,8 +286,8 @@ Input telemetry:
 - `renderFrameMaxMs`: maximum observed render-thread draw duration for this process
 - `readbackQueueMs`: time spent queueing the most recent async BGRA8 PBO readback
 - `completedReadbackCopyMs`: time spent mapping/copying the most recent completed readback into system-memory frame storage
-- `completedDrops`: completed unscheduled system-memory frames dropped so render could reuse the slot
-- `acquireMisses`: times render/readback could not acquire a writable system-memory frame slot
+- `completedDrops`: completed unscheduled system-memory frames dropped by latest-N acquire paths; expected to stay flat in the cadence compositor output path
+- `acquireMisses`: times render/readback could not acquire a writable system-memory frame slot; completed frames waiting for playout are preserved instead of being displaced
 - `inputConsumeMisses`: render ticks where no ready input frame was available to upload
 - `inputUploadMisses`: input texture upload attempts that reused the previous GL input texture
 - `inputReadyFrames`: ready input frames currently queued in `InputFrameMailbox`
diff --git a/apps/RenderCadenceCompositor/RenderCadenceCompositor.cpp b/apps/RenderCadenceCompositor/RenderCadenceCompositor.cpp
index 7a707a1..267735b 100644
--- a/apps/RenderCadenceCompositor/RenderCadenceCompositor.cpp
+++ b/apps/RenderCadenceCompositor/RenderCadenceCompositor.cpp
@@ -111,14 +111,23 @@ int main(int argc, char** argv)
 	InputFrameMailbox inputMailbox(inputMailboxConfig);
 
 	VideoFormat inputVideoMode;
+	VideoFormat outputVideoMode;
 	std::string inputVideoModeError;
 	const bool inputVideoModeResolved = ResolveConfiguredVideoFormat(appConfig.inputVideoFormat, appConfig.inputFrameRate, inputVideoMode);
+	const bool outputVideoModeResolved = ResolveConfiguredVideoFormat(appConfig.outputVideoFormat, appConfig.outputFrameRate, outputVideoMode);
 	if (!inputVideoModeResolved)
 	{
 		inputVideoModeError = "Unsupported DeckLink inputVideoFormat/inputFrameRate in config/runtime-host.json: " +
 			appConfig.inputVideoFormat + " / " + appConfig.inputFrameRate;
 		RenderCadenceCompositor::LogWarning("app", inputVideoModeError);
 	}
+	if (!outputVideoModeResolved)
+	{
+		RenderCadenceCompositor::LogWarning(
+			"app",
+			"Unsupported DeckLink outputVideoFormat/outputFrameRate in config/runtime-host.json; render cadence will use parsed frame-rate fallback: " +
+				appConfig.outputVideoFormat + " / " + appConfig.outputFrameRate);
+	}
 
 	RenderCadenceCompositor::DeckLinkInput deckLinkInput(inputMailbox);
 	RenderCadenceCompositor::DeckLinkInputThread deckLinkInputThread(deckLinkInput);
@@ -173,7 +182,10 @@ int main(int argc, char** argv)
 	RenderThread::Config renderConfig;
 	renderConfig.width = frameExchangeConfig.width;
 	renderConfig.height = frameExchangeConfig.height;
-	renderConfig.frameDurationMilliseconds = RenderCadenceCompositor::FrameDurationMillisecondsFromRateString(appConfig.outputFrameRate);
+	const double fallbackFrameDurationMilliseconds = RenderCadenceCompositor::FrameDurationMillisecondsFromRateString(appConfig.outputFrameRate);
+	renderConfig.frameDurationMilliseconds = outputVideoModeResolved
+		? RenderCadenceCompositor::FrameDurationMillisecondsFromDisplayMode(outputVideoMode.displayMode, fallbackFrameDurationMilliseconds)
+		: fallbackFrameDurationMilliseconds;
 	renderConfig.pboDepth = 6;
 
 	RenderThread renderThread(frameExchange, &inputMailbox, renderConfig);
diff --git a/apps/RenderCadenceCompositor/app/AppConfigProvider.cpp b/apps/RenderCadenceCompositor/app/AppConfigProvider.cpp
index bef9c57..d10604c 100644
--- a/apps/RenderCadenceCompositor/app/AppConfigProvider.cpp
+++ b/apps/RenderCadenceCompositor/app/AppConfigProvider.cpp
@@ -4,6 +4,7 @@
 
 #include <algorithm>
 #include <cctype>
+#include <cstdint>
 #include <cstdlib>
 #include <fstream>
 #include <sstream>
@@ -184,6 +185,50 @@ double FrameDurationMillisecondsFromRateString(const std::string& rateText, doub
 	return 1000.0 / rate;
 }
 
+double FrameDurationMillisecondsFromDisplayMode(BMDDisplayMode displayMode, double fallbackMilliseconds)
+{
+	struct ModeRate
+	{
+		BMDDisplayMode mode;
+		int64_t frameDuration;
+		int64_t timeScale;
+	};
+
+	static const ModeRate rates[] =
+	{
+		{ bmdModeHD720p50, 1, 50 },
+		{ bmdModeHD720p5994, 1001, 60000 },
+		{ bmdModeHD720p60, 1, 60 },
+		{ bmdModeHD1080i50, 1, 25 },
+		{ bmdModeHD1080i5994, 1001, 30000 },
+		{ bmdModeHD1080i6000, 1, 30 },
+		{ bmdModeHD1080p2398, 1001, 24000 },
+		{ bmdModeHD1080p24, 1, 24 },
+		{ bmdModeHD1080p25, 1, 25 },
+		{ bmdModeHD1080p2997, 1001, 30000 },
+		{ bmdModeHD1080p30, 1, 30 },
+		{ bmdModeHD1080p50, 1, 50 },
+		{ bmdModeHD1080p5994, 1001, 60000 },
+		{ bmdModeHD1080p6000, 1, 60 },
+		{ bmdMode4K2160p2398, 1001, 24000 },
+		{ bmdMode4K2160p24, 1, 24 },
+		{ bmdMode4K2160p25, 1, 25 },
+		{ bmdMode4K2160p2997, 1001, 30000 },
+		{ bmdMode4K2160p30, 1, 30 },
+		{ bmdMode4K2160p50, 1, 50 },
+		{ bmdMode4K2160p5994, 1001, 60000 },
+		{ bmdMode4K2160p60, 1, 60 }
+	};
+
+	for (const ModeRate& rate : rates)
+	{
+		if (rate.mode == displayMode && rate.timeScale > 0)
+			return (static_cast<double>(rate.frameDuration) * 1000.0) / static_cast<double>(rate.timeScale);
+	}
+
+	return fallbackMilliseconds;
+}
+
 void VideoFormatDimensions(const std::string& formatName, unsigned& width, unsigned& height)
 {
 	std::string normalized = formatName;
diff --git a/apps/RenderCadenceCompositor/app/AppConfigProvider.h b/apps/RenderCadenceCompositor/app/AppConfigProvider.h
index 5477b7d..4992311 100644
--- a/apps/RenderCadenceCompositor/app/AppConfigProvider.h
+++ b/apps/RenderCadenceCompositor/app/AppConfigProvider.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "AppConfig.h"
+#include "DeckLinkDisplayMode.h"
 
 #include <filesystem>
 #include <string>
@@ -27,6 +28,7 @@ private:
 };
 
 double FrameDurationMillisecondsFromRateString(const std::string& rateText, double fallbackRate = 59.94);
+double FrameDurationMillisecondsFromDisplayMode(BMDDisplayMode displayMode, double fallbackMilliseconds);
 void VideoFormatDimensions(const std::string& formatName, unsigned& width, unsigned& height);
 std::filesystem::path FindConfigFile(const std::filesystem::path& relativePath = "config/runtime-host.json");
 std::filesystem::path FindRepoPath(const std::filesystem::path& relativePath);
diff --git a/apps/RenderCadenceCompositor/frames/InputFrameMailbox.cpp b/apps/RenderCadenceCompositor/frames/InputFrameMailbox.cpp
index c3137d2..b60a92d 100644
--- a/apps/RenderCadenceCompositor/frames/InputFrameMailbox.cpp
+++ b/apps/RenderCadenceCompositor/frames/InputFrameMailbox.cpp
@@ -120,38 +120,6 @@ bool InputFrameMailbox::SubmitFrame(const void* bytes, unsigned rowBytes, uint64
 	return true;
 }
 
-bool InputFrameMailbox::TryAcquireLatest(InputFrame& frame)
-{
-	std::lock_guard<std::mutex> lock(mMutex);
-	while (!mReadyIndices.empty())
-	{
-		const std::size_t index = mReadyIndices.back();
-		mReadyIndices.pop_back();
-		if (index >= mSlots.size() || mSlots[index].state != InputFrameSlotState::Ready)
-			continue;
-
-		while (!mReadyIndices.empty())
-		{
-			const std::size_t olderIndex = mReadyIndices.front();
-			mReadyIndices.pop_front();
-			if (olderIndex >= mSlots.size() || mSlots[olderIndex].state != InputFrameSlotState::Ready)
-				continue;
-			mSlots[olderIndex].state = InputFrameSlotState::Free;
-			++mSlots[olderIndex].generation;
-			++mCounters.droppedReadyFrames;
-		}
-
-		mSlots[index].state = InputFrameSlotState::Reading;
-		FillFrameLocked(index, frame);
-		++mCounters.consumedFrames;
-		return true;
-	}
-
-	frame = InputFrame();
-	++mCounters.consumeMisses;
-	return false;
-}
-
 bool InputFrameMailbox::TryAcquireOldest(InputFrame& frame)
 {
 	std::lock_guard<std::mutex> lock(mMutex);
diff --git a/apps/RenderCadenceCompositor/frames/InputFrameMailbox.h b/apps/RenderCadenceCompositor/frames/InputFrameMailbox.h
index 60284a6..74a8522 100644
--- a/apps/RenderCadenceCompositor/frames/InputFrameMailbox.h
+++ b/apps/RenderCadenceCompositor/frames/InputFrameMailbox.h
@@ -64,7 +64,6 @@ public:
 	InputFrameMailboxConfig Config() const;
 
 	bool SubmitFrame(const void* bytes, unsigned rowBytes, uint64_t frameIndex);
-	bool TryAcquireLatest(InputFrame& frame);
 	bool TryAcquireOldest(InputFrame& frame);
 	bool Release(const InputFrame& frame);
 	void Clear();
diff --git a/apps/RenderCadenceCompositor/frames/SystemFrameExchange.cpp b/apps/RenderCadenceCompositor/frames/SystemFrameExchange.cpp
index 59d3e37..6f06682 100644
--- a/apps/RenderCadenceCompositor/frames/SystemFrameExchange.cpp
+++ b/apps/RenderCadenceCompositor/frames/SystemFrameExchange.cpp
@@ -47,12 +47,9 @@ bool SystemFrameExchange::AcquireForRender(SystemFrame& frame)
 	std::lock_guard<std::mutex> lock(mMutex);
 	if (!AcquireFreeLocked(frame))
 	{
-		if (!DropOldestCompletedLocked() || !AcquireFreeLocked(frame))
-		{
-			frame = SystemFrame();
-			++mCounters.acquireMisses;
-			return false;
-		}
+		frame = SystemFrame();
+		++mCounters.acquireMisses;
+		return false;
 	}
 
 	++mCounters.acquiredFrames;
@@ -234,27 +231,6 @@ bool SystemFrameExchange::AcquireFreeLocked(SystemFrame& frame)
 	return false;
 }
 
-bool SystemFrameExchange::DropOldestCompletedLocked()
-{
-	while (!mCompletedIndices.empty())
-	{
-		const std::size_t index = mCompletedIndices.front();
-		mCompletedIndices.pop_front();
-		if (index >= mSlots.size() || mSlots[index].state != SystemFrameSlotState::Completed)
-			continue;
-
-		Slot& slot = mSlots[index];
-		slot.state = SystemFrameSlotState::Free;
-		slot.frameIndex = 0;
-		++slot.generation;
-		++mCounters.completedDrops;
-		mCondition.notify_all();
-		return true;
-	}
-
-	return false;
-}
-
 bool SystemFrameExchange::IsValidLocked(const SystemFrame& frame) const
 {
 	return frame.index < mSlots.size() && mSlots[frame.index].generation == frame.generation;
diff --git a/apps/RenderCadenceCompositor/frames/SystemFrameExchange.h b/apps/RenderCadenceCompositor/frames/SystemFrameExchange.h
index 7968b4c..5dd429b 100644
--- a/apps/RenderCadenceCompositor/frames/SystemFrameExchange.h
+++ b/apps/RenderCadenceCompositor/frames/SystemFrameExchange.h
@@ -40,7 +40,6 @@ private:
 	};
 
 	bool AcquireFreeLocked(SystemFrame& frame);
-	bool DropOldestCompletedLocked();
 	bool IsValidLocked(const SystemFrame& frame) const;
 	void FillFrameLocked(std::size_t index, SystemFrame& frame);
 	std::size_t CompletedCountLocked() const;
diff --git a/apps/RenderCadenceCompositor/render/runtime/RuntimeRenderSceneRender.cpp b/apps/RenderCadenceCompositor/render/runtime/RuntimeRenderSceneRender.cpp
index c3e2cfb..65ff2e5 100644
--- a/apps/RenderCadenceCompositor/render/runtime/RuntimeRenderSceneRender.cpp
+++ b/apps/RenderCadenceCompositor/render/runtime/RuntimeRenderSceneRender.cpp
@@ -65,7 +65,7 @@ void RuntimeRenderScene::RenderFrame(uint64_t frameIndex, unsigned width, unsign
 	}
 
 	// Shader source contract:
-	// - gVideoInput is the decoded latest input texture for every layer in the stack.
+	// - gVideoInput is the decoded current input texture for every layer in the stack.
 	// - gLayerInput starts as gVideoInput for the first layer, then becomes the previous layer output.
 	GLuint layerInputTexture = videoInputTexture;
 	std::size_t nextTargetIndex = 0;
diff --git a/apps/RenderCadenceCompositor/video/DeckLinkOutputThread.h b/apps/RenderCadenceCompositor/video/DeckLinkOutputThread.h
index 6aacae9..0c06bac 100644
--- a/apps/RenderCadenceCompositor/video/DeckLinkOutputThread.h
+++ b/apps/RenderCadenceCompositor/video/DeckLinkOutputThread.h
@@ -82,7 +82,6 @@ private:
 				std::this_thread::sleep_for(mConfig.idleSleep);
 				continue;
 			}
-
 			SystemFrame frame;
 			if (!mExchange.ConsumeCompletedForSchedule(frame))
 			{
diff --git a/tests/RenderCadenceCompositorAppConfigProviderTests.cpp b/tests/RenderCadenceCompositorAppConfigProviderTests.cpp
index 7986912..408fb50 100644
--- a/tests/RenderCadenceCompositorAppConfigProviderTests.cpp
+++ b/tests/RenderCadenceCompositorAppConfigProviderTests.cpp
@@ -107,6 +107,8 @@ void TestHelpers()
 
 	const double duration = FrameDurationMillisecondsFromRateString("50");
 	Expect(duration > 19.9 && duration < 20.1, "frame duration parses numeric rate");
+	const double deckLinkDuration = FrameDurationMillisecondsFromDisplayMode(bmdModeHD1080p5994, 0.0);
+	Expect(deckLinkDuration > 16.6833 && deckLinkDuration < 16.6834, "DeckLink 59.94 display mode duration is exact");
 
 	const std::filesystem::path configPath = FindConfigFile();
 	Expect(!configPath.empty(), "default config is discoverable from test working directory");
diff --git a/tests/RenderCadenceCompositorFrameExchangeTests.cpp b/tests/RenderCadenceCompositorFrameExchangeTests.cpp
index 93dbc14..9c7af12 100644
--- a/tests/RenderCadenceCompositorFrameExchangeTests.cpp
+++ b/tests/RenderCadenceCompositorFrameExchangeTests.cpp
@@ -57,32 +57,29 @@ void TestAcquirePublishesAndSchedules()
 	Expect(metrics.scheduledFrames == 1, "scheduled metric is counted");
 }
 
-void TestAcquireDropsOldestCompletedUnscheduled()
+void TestAcquirePreservesCompletedFrames()
 {
 	SystemFrameExchange exchange(MakeConfig(2));
 
 	SystemFrame first;
 	SystemFrame second;
 	SystemFrame third;
-	Expect(exchange.AcquireForRender(first), "first frame can be acquired");
+	Expect(exchange.AcquireForRender(first), "first preserving frame can be acquired");
 	first.frameIndex = 1;
-	Expect(exchange.PublishCompleted(first), "first frame can be completed");
-	Expect(exchange.AcquireForRender(second), "second frame can be acquired");
+	Expect(exchange.PublishCompleted(first), "first preserving frame can be completed");
+	Expect(exchange.AcquireForRender(second), "second preserving frame can be acquired");
 	second.frameIndex = 2;
-	Expect(exchange.PublishCompleted(second), "second frame can be completed");
+	Expect(exchange.PublishCompleted(second), "second preserving frame can be completed");
 
-	Expect(exchange.AcquireForRender(third), "third acquire drops the oldest completed frame");
-	Expect(third.index == first.index, "oldest completed slot is reused");
+	Expect(!exchange.AcquireForRender(third), "render acquire refuses to drop completed frames");
 
 	SystemFrame scheduled;
-	Expect(exchange.ConsumeCompletedForSchedule(scheduled), "remaining completed frame can be scheduled");
-	Expect(scheduled.index == second.index, "newer completed frame survives drop");
-	Expect(scheduled.frameIndex == 2, "newer frame index survives drop");
+	Expect(exchange.ConsumeCompletedForSchedule(scheduled), "oldest completed frame survives acquire miss");
+	Expect(scheduled.frameIndex == 1, "preserving acquire keeps FIFO output continuity");
 
 	SystemFrameExchangeMetrics metrics = exchange.Metrics();
-	Expect(metrics.completedDrops == 1, "drop metric is counted");
-	Expect(metrics.renderingCount == 1, "reused slot is rendering");
-	Expect(metrics.scheduledCount == 1, "consumed slot is scheduled");
+	Expect(metrics.completedDrops == 0, "preserving acquire does not count completed drops");
+	Expect(metrics.acquireMisses == 1, "preserving acquire miss is counted");
 }
 
 void TestScheduledFramesAreNotDropped()
@@ -179,7 +176,7 @@ void TestStableCompletedDepthTimesOut()
 int main()
 {
 	TestAcquirePublishesAndSchedules();
-	TestAcquireDropsOldestCompletedUnscheduled();
+	TestAcquirePreservesCompletedFrames();
 	TestScheduledFramesAreNotDropped();
 	TestGenerationValidationRejectsStaleFrames();
 	TestPixelFormatAwareSizing();
diff --git a/tests/RenderCadenceCompositorInputFrameMailboxTests.cpp b/tests/RenderCadenceCompositorInputFrameMailboxTests.cpp
index 19bfb4b..3702a44 100644
--- a/tests/RenderCadenceCompositorInputFrameMailboxTests.cpp
+++ b/tests/RenderCadenceCompositorInputFrameMailboxTests.cpp
@@ -41,28 +41,6 @@ std::vector<unsigned char> MakeFrame(unsigned char value)
 	return std::vector<unsigned char>(16, value);
 }
 
-void TestAcquireLatestDropsOlderReadyFrames()
-{
-	InputFrameMailbox mailbox(MakeConfig(3));
-	const std::vector<unsigned char> frame1 = MakeFrame(1);
-	const std::vector<unsigned char> frame2 = MakeFrame(2);
-	const std::vector<unsigned char> frame3 = MakeFrame(3);
-
-	Expect(mailbox.SubmitFrame(frame1.data(), 8, 1), "first input frame submits");
-	Expect(mailbox.SubmitFrame(frame2.data(), 8, 2), "second input frame submits");
-	Expect(mailbox.SubmitFrame(frame3.data(), 8, 3), "third input frame submits");
-
-	InputFrame latest;
-	Expect(mailbox.TryAcquireLatest(latest), "latest input frame can be acquired");
-	Expect(latest.frameIndex == 3, "mailbox returns newest frame");
-	Expect(latest.bytes != nullptr && static_cast<const unsigned char*>(latest.bytes)[0] == 3, "latest frame bytes match newest frame");
-	Expect(mailbox.Release(latest), "latest input frame can be released");
-
-	const InputFrameMailboxMetrics metrics = mailbox.Metrics();
-	Expect(metrics.droppedReadyFrames == 2, "older ready input frames are dropped after latest acquire");
-	Expect(metrics.freeCount == 3, "all slots are free after release");
-}
-
 void TestSubmitDropsOldestWhenFull()
 {
 	InputFrameMailbox mailbox(MakeConfig(2));
@@ -74,10 +52,10 @@ void TestSubmitDropsOldestWhenFull()
 	Expect(mailbox.SubmitFrame(frame2.data(), 8, 2), "second frame submits into full test");
 	Expect(mailbox.SubmitFrame(frame3.data(), 8, 3), "third frame submits by dropping oldest ready frame");
 
-	InputFrame latest;
-	Expect(mailbox.TryAcquireLatest(latest), "latest frame available after drop");
-	Expect(latest.frameIndex == 3, "newest frame survived full mailbox");
-	Expect(mailbox.Release(latest), "newest frame releases");
+	InputFrame oldest;
+	Expect(mailbox.TryAcquireOldest(oldest), "oldest frame available after drop");
+	Expect(oldest.frameIndex == 2, "bounded mailbox keeps FIFO order after trimming oldest overflow");
+	Expect(mailbox.Release(oldest), "oldest frame releases");
 
 	const InputFrameMailboxMetrics metrics = mailbox.Metrics();
 	Expect(metrics.droppedReadyFrames >= 1, "full mailbox records ready drop");
@@ -92,7 +70,7 @@ void TestReadingFrameIsProtected()
 
 	Expect(mailbox.SubmitFrame(frame1.data(), 8, 1), "protected frame submits");
 	InputFrame acquired;
-	Expect(mailbox.TryAcquireLatest(acquired), "protected frame acquired");
+	Expect(mailbox.TryAcquireOldest(acquired), "protected frame acquired");
 	Expect(!mailbox.SubmitFrame(frame2.data(), 8, 2), "producer cannot overwrite frame currently being read");
 	Expect(mailbox.Release(acquired), "protected frame releases");
 	Expect(mailbox.SubmitFrame(frame2.data(), 8, 2), "producer can submit after release");
@@ -143,7 +121,6 @@ void TestMaxReadyFramesKeepsConfiguredInputBuffer()
 
 int main()
 {
-	TestAcquireLatestDropsOlderReadyFrames();
 	TestSubmitDropsOldestWhenFull();
 	TestReadingFrameIsProtected();
 	TestAcquireOldestConsumesFifoWithoutDroppingReadyFrames();
diff --git a/tests/VideoPlayoutSchedulerTests.cpp b/tests/VideoPlayoutSchedulerTests.cpp
index cac491e..61524e0 100644
--- a/tests/VideoPlayoutSchedulerTests.cpp
+++ b/tests/VideoPlayoutSchedulerTests.cpp
@@ -70,6 +70,19 @@ void TestDefaultPolicyReportsLagWithoutSkippingScheduleTime()
 	Expect(scheduler.NextScheduleTime().streamTime == 1000, "default recovery keeps stream time continuous");
 }
 
+void TestScheduleCursorCanAlignToPlaybackClock()
+{
+	VideoPlayoutScheduler scheduler;
+	scheduler.Configure(1000, 50000);
+
+	(void)scheduler.NextScheduleTime();
+	scheduler.AlignNextScheduleTimeToPlayback(10000, 4);
+	Expect(scheduler.NextScheduleTime().streamTime == 14000, "schedule cursor skips stale stream time after underfeed");
+
+	scheduler.AlignNextScheduleTimeToPlayback(11000, 1);
+	Expect(scheduler.NextScheduleTime().streamTime == 15000, "schedule cursor does not move backward");
+}
+
 void TestMeasuredRecoveryIsCappedByPolicy()
 {
 	VideoPlayoutPolicy policy;
@@ -133,6 +146,7 @@ int main()
 	TestScheduleAdvancesFromZero();
 	TestLateAndDroppedRecoveryUsesMeasuredPressure();
 	TestDefaultPolicyReportsLagWithoutSkippingScheduleTime();
+	TestScheduleCursorCanAlignToPlaybackClock();
 	TestMeasuredRecoveryIsCappedByPolicy();
 	TestCleanCompletionTracksCompletedIndexAndClearsStreaks();
 	TestPolicyNormalization();