Revert "Decklink separation"

This reverts commit 46f2f1ece5.
Decklink separation
2026-05-09 16:47:33 +10:00 · 2026-05-09 14:42:11 +10:00 · 2026-05-09 14:15:49 +10:00 · 2026-05-09 13:53:00 +10:00 · 2026-05-09 13:50:27 +10:00 · 2026-05-08 20:32:19 +10:00
51 changed files with 1515 additions and 305 deletions
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -49,6 +49,10 @@ set(APP_SOURCES
 	"${APP_DIR}/videoio/decklink/DeckLinkSession.h"
 	"${APP_DIR}/videoio/decklink/DeckLinkVideoIOFormat.cpp"
 	"${APP_DIR}/videoio/decklink/DeckLinkVideoIOFormat.h"
+	"${APP_DIR}/videoio/VideoIOBackendFactory.cpp"
+	"${APP_DIR}/videoio/VideoIOBackendFactory.h"
+	"${APP_DIR}/videoio/VideoIOConfig.cpp"
+	"${APP_DIR}/videoio/VideoIOConfig.h"
 	"${APP_DIR}/gl/renderer/GLExtensions.cpp"
 	"${APP_DIR}/gl/renderer/GLExtensions.h"
 	"${APP_DIR}/gl/shader/GlobalParamsBuffer.cpp"
@@ -204,6 +208,35 @@ endif()

 add_test(NAME RuntimeParameterUtilsTests COMMAND RuntimeParameterUtilsTests)

+add_executable(RuntimeHostVideoIOStateTests
+	"${APP_DIR}/runtime/RuntimeHost.cpp"
+	"${APP_DIR}/runtime/RuntimeClock.cpp"
+	"${APP_DIR}/runtime/RuntimeJson.cpp"
+	"${APP_DIR}/runtime/RuntimeParameterUtils.cpp"
+	"${APP_DIR}/shader/ShaderCompiler.cpp"
+	"${APP_DIR}/shader/ShaderPackageRegistry.cpp"
+	"${APP_DIR}/videoio/VideoIOConfig.cpp"
+	"${CMAKE_CURRENT_SOURCE_DIR}/tests/RuntimeHostVideoIOStateTests.cpp"
+)
+
+target_include_directories(RuntimeHostVideoIOStateTests PRIVATE
+	"${APP_DIR}"
+	"${APP_DIR}/platform"
+	"${APP_DIR}/runtime"
+	"${APP_DIR}/shader"
+	"${APP_DIR}/videoio"
+)
+
+target_link_libraries(RuntimeHostVideoIOStateTests PRIVATE
+	Advapi32
+)
+
+if(MSVC)
+	target_compile_options(RuntimeHostVideoIOStateTests PRIVATE /W3)
+endif()
+
+add_test(NAME RuntimeHostVideoIOStateTests COMMAND RuntimeHostVideoIOStateTests)
+
 add_executable(Std140BufferTests
 	"${CMAKE_CURRENT_SOURCE_DIR}/tests/Std140BufferTests.cpp"
 )
@@ -318,6 +351,7 @@ endif()
 add_test(NAME VideoPlayoutSchedulerTests COMMAND VideoPlayoutSchedulerTests)

 add_executable(VideoIODeviceFakeTests
+	"${APP_DIR}/videoio/VideoIOConfig.cpp"
 	"${APP_DIR}/videoio/VideoIOFormat.cpp"
 	"${CMAKE_CURRENT_SOURCE_DIR}/tests/VideoIODeviceFakeTests.cpp"
 )
@@ -334,6 +368,43 @@ endif()

 add_test(NAME VideoIODeviceFakeTests COMMAND VideoIODeviceFakeTests)

+add_executable(VideoIOBackendFactoryTests
+	"${APP_DIR}/videoio/decklink/DeckLinkAPI_i.c"
+	"${APP_DIR}/videoio/decklink/DeckLinkSession.cpp"
+	"${APP_DIR}/videoio/decklink/DeckLinkSession.h"
+	"${APP_DIR}/videoio/decklink/DeckLinkDisplayMode.cpp"
+	"${APP_DIR}/videoio/decklink/DeckLinkDisplayMode.h"
+	"${APP_DIR}/videoio/decklink/DeckLinkVideoIOFormat.cpp"
+	"${APP_DIR}/videoio/decklink/DeckLinkVideoIOFormat.h"
+	"${APP_DIR}/videoio/decklink/DeckLinkFrameTransfer.cpp"
+	"${APP_DIR}/videoio/decklink/DeckLinkFrameTransfer.h"
+	"${APP_DIR}/videoio/VideoIOBackendFactory.cpp"
+	"${APP_DIR}/videoio/VideoIOBackendFactory.h"
+	"${APP_DIR}/videoio/VideoIOConfig.cpp"
+	"${APP_DIR}/videoio/VideoIOConfig.h"
+	"${APP_DIR}/videoio/VideoIOFormat.cpp"
+	"${APP_DIR}/videoio/VideoPlayoutScheduler.cpp"
+	"${APP_DIR}/videoio/VideoPlayoutScheduler.h"
+	"${CMAKE_CURRENT_SOURCE_DIR}/tests/VideoIOBackendFactoryTests.cpp"
+)
+
+target_include_directories(VideoIOBackendFactoryTests PRIVATE
+	"${APP_DIR}"
+	"${APP_DIR}/gl/renderer"
+	"${APP_DIR}/videoio"
+	"${APP_DIR}/videoio/decklink"
+)
+
+target_link_libraries(VideoIOBackendFactoryTests PRIVATE
+	Ole32
+)
+
+if(MSVC)
+	target_compile_options(VideoIOBackendFactoryTests PRIVATE /W3)
+endif()
+
+add_test(NAME VideoIOBackendFactoryTests COMMAND VideoIOBackendFactoryTests)
+
 install(TARGETS LoopThroughWithOpenGLCompositing
 	RUNTIME DESTINATION "."
 )
--- a/README.md
+++ b/README.md
@@ -273,3 +273,5 @@ If `SLANG_ROOT` is not set, the workflow falls back to the repo-local default un
 - compute shaders or a small 1x1 or nx1 RGBA16f render target for arbitrary data storage
 - allow shaders to read other shaders data store based on name? or output over OSC
 - Mipmapping for shader-declared textures
+- Anotate included shaders
+- allow 3 vector exposed controls
--- a/apps/LoopThroughWithOpenGLCompositing/LoopThroughWithOpenGLCompositing.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/LoopThroughWithOpenGLCompositing.cpp
@@ -412,10 +412,10 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 				break;
 			}

-			// Setup OpenGL and DeckLink capture and playout object
+			// Setup OpenGL and video I/O capture/playout object
 			pOpenGLComposite = new OpenGLComposite(hWnd, hDC, hRC);

-			if (pOpenGLComposite->InitDeckLink())
+			if (pOpenGLComposite->InitializeVideoIO())
 			{
 				wglMakeCurrent( NULL, NULL );
 				if (pOpenGLComposite->Start())
@@ -423,11 +423,11 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 					PostMessage(hWnd, kCreateStatusStripMessage, 0, 0);
 					break;						// success
 				}
-				MessageBoxA(NULL, "The OpenGL/DeckLink runtime initialized, but playout failed to start. See the previous DeckLink start message for the failing call.", "Startup failed", MB_OK | MB_ICONERROR);
+				MessageBoxA(NULL, "The OpenGL/video I/O runtime initialized, but playout failed to start. See the previous start message for the failing call.", "Startup failed", MB_OK | MB_ICONERROR);
 			}
 			else
 			{
-				MessageBoxA(NULL, "The OpenGL/DeckLink runtime failed to initialize. See the previous initialization message for the failing call.", "Startup failed", MB_OK | MB_ICONERROR);
+				MessageBoxA(NULL, "The OpenGL/video I/O runtime failed to initialize. See the previous initialization message for the failing call.", "Startup failed", MB_OK | MB_ICONERROR);
 			}

 			// Failed to initialize - cleanup
@@ -438,7 +438,7 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 			}
 			catch (...)
 			{
-				ShowUnhandledExceptionMessage("Startup failed while creating the OpenGL/DeckLink runtime.");
+				ShowUnhandledExceptionMessage("Startup failed while creating the OpenGL/video I/O runtime.");
 				PostMessage(hWnd, WM_CLOSE, 0, 0);
 				break;
 			}
@@ -474,7 +474,7 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 			}
 			catch (...)
 			{
-				ShowUnhandledExceptionMessage("Shutdown failed while tearing down the OpenGL/DeckLink runtime.");
+				ShowUnhandledExceptionMessage("Shutdown failed while tearing down the OpenGL/video I/O runtime.");
 			}

 			// Deselect the current rendering context and delete it
--- a/apps/LoopThroughWithOpenGLCompositing/control/ControlServer.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/control/ControlServer.cpp
@@ -501,6 +501,9 @@ bool ControlServer::SendWebSocketText(SOCKET clientSocket, const std::string& pa

 void ControlServer::BroadcastStateLocked()
 {
+	if (mClients.empty())
+		return;
+
 	const std::string stateMessage = mCallbacks.getStateJson ? mCallbacks.getStateJson() : "{}";
 	for (auto it = mClients.begin(); it != mClients.end();)
 	{
--- a/apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.cpp
@@ -1,5 +1,3 @@
-#include "DeckLinkDisplayMode.h"
-#include "DeckLinkSession.h"
 #include "OpenGLComposite.h"
 #include "GLExtensions.h"
 #include "GlRenderConstants.h"
@@ -10,6 +8,7 @@
 #include "PngScreenshotWriter.h"
 #include "RuntimeServices.h"
 #include "ShaderBuildQueue.h"
+#include "VideoIOBackendFactory.h"

 #include <algorithm>
 #include <chrono>
@@ -23,7 +22,6 @@

 OpenGLComposite::OpenGLComposite(HWND hWnd, HDC hDC, HGLRC hRC) :
 	hGLWnd(hWnd), hGLDC(hDC), hGLRC(hRC),
-	mVideoIO(std::make_unique<DeckLinkSession>()),
 	mRenderer(std::make_unique<OpenGLRenderer>()),
 	mUseCommittedLayerStates(false),
 	mScreenshotRequested(false)
@@ -37,7 +35,7 @@ OpenGLComposite::OpenGLComposite(HWND hWnd, HDC hDC, HGLRC hRC) :
 		[this]() { ProcessScreenshotRequest(); },
 		[this]() { paintGL(); });
 	mVideoIOBridge = std::make_unique<OpenGLVideoIOBridge>(
-		*mVideoIO,
+		nullptr,
 		*mRenderer,
 		*mRenderPipeline,
 		*mRuntimeHost,
@@ -56,20 +54,15 @@ OpenGLComposite::~OpenGLComposite()
 		mRuntimeServices->Stop();
 	if (mShaderBuildQueue)
 		mShaderBuildQueue->Stop();
-	mVideoIO->ReleaseResources();
+	if (mVideoIO)
+		mVideoIO->ReleaseResources();
 	mRenderer->DestroyResources();

 	DeleteCriticalSection(&pMutex);
 }

-bool OpenGLComposite::InitDeckLink()
+bool OpenGLComposite::InitializeVideoIO()
 {
-	return InitVideoIO();
-}
-
-bool OpenGLComposite::InitVideoIO()
-{
-	VideoFormatSelection		videoModes;
 	std::string						initFailureReason;

 	if (mRuntimeHost && mRuntimeHost->GetRepoRoot().empty())
@@ -82,31 +75,31 @@ bool OpenGLComposite::InitVideoIO()
 		}
 	}

-	if (mRuntimeHost)
+	if (!mRuntimeHost)
 	{
-		if (!ResolveConfiguredVideoFormats(
-			mRuntimeHost->GetInputVideoFormat(),
-			mRuntimeHost->GetInputFrameRate(),
-			mRuntimeHost->GetOutputVideoFormat(),
-			mRuntimeHost->GetOutputFrameRate(),
-			videoModes,
-			initFailureReason))
-		{
-			MessageBoxA(NULL, initFailureReason.c_str(), "DeckLink mode configuration error", MB_OK);
-			return false;
-		}
+		initFailureReason = "Runtime host is not available.";
+		MessageBoxA(NULL, initFailureReason.c_str(), "Video I/O initialization failed", MB_OK | MB_ICONERROR);
+		return false;
 	}

-	if (!mVideoIO->DiscoverDevicesAndModes(videoModes, initFailureReason))
+	const VideoIOConfiguration videoIOConfig = mRuntimeHost->GetVideoIOConfiguration();
+	mVideoIO = CreateVideoIODevice(videoIOConfig.backendId, initFailureReason);
+	if (!mVideoIO)
+	{
+		MessageBoxA(NULL, initFailureReason.c_str(), "Video I/O initialization failed", MB_OK | MB_ICONERROR);
+		return false;
+	}
+	mVideoIOBridge->SetVideoIODevice(mVideoIO.get());
+
+	if (!mVideoIO->DiscoverDevicesAndModes(videoIOConfig, initFailureReason))
 	{
 		const char* title = initFailureReason == "Please install the Blackmagic DeckLink drivers to use the features of this application."
-			? "This application requires the DeckLink drivers installed."
-			: "DeckLink initialization failed";
+			? "This application requires the selected video I/O drivers installed."
+			: "Video I/O initialization failed";
 		MessageBoxA(NULL, initFailureReason.c_str(), title, MB_OK | MB_ICONERROR);
 		return false;
 	}
-	const bool outputAlphaRequired = mRuntimeHost && mRuntimeHost->ExternalKeyingEnabled();
-	if (!mVideoIO->SelectPreferredFormats(videoModes, outputAlphaRequired, initFailureReason))
+	if (!mVideoIO->SelectPreferredFormats(videoIOConfig, initFailureReason))
 		goto error;

 	if (! CheckOpenGLExtensions())
@@ -121,9 +114,9 @@ bool OpenGLComposite::InitVideoIO()
 		goto error;
 	}

-	PublishVideoIOStatus(mVideoIO->OutputModelName().empty()
-		? "DeckLink output device selected."
-		: ("Selected output device: " + mVideoIO->OutputModelName()));
+	PublishVideoIOStatus(mVideoIO->DeviceName().empty()
+		? "Video I/O output device selected."
+		: ("Selected output device: " + mVideoIO->DeviceName()));

 	// Resize window to match output video frame, but scale large formats down by half for viewing.
 	if (mVideoIO->OutputFrameWidth() < 1920)
@@ -131,7 +124,7 @@ bool OpenGLComposite::InitVideoIO()
 	else
 		resizeWindow(mVideoIO->OutputFrameWidth() / 2, mVideoIO->OutputFrameHeight() / 2);

-	if (!mVideoIO->ConfigureInput([this](const VideoIOFrame& frame) { mVideoIOBridge->VideoFrameArrived(frame); }, videoModes.input, initFailureReason))
+	if (!mVideoIO->ConfigureInput([this](const VideoIOFrame& frame) { mVideoIOBridge->VideoFrameArrived(frame); }, initFailureReason))
 	{
 		goto error;
 	}
@@ -140,7 +133,7 @@ bool OpenGLComposite::InitVideoIO()
 		mRuntimeHost->SetSignalStatus(false, mVideoIO->InputFrameWidth(), mVideoIO->InputFrameHeight(), mVideoIO->InputDisplayModeName());
 	}

-	if (!mVideoIO->ConfigureOutput([this](const VideoIOCompletion& completion) { mVideoIOBridge->PlayoutFrameCompleted(completion); }, videoModes.output, mRuntimeHost && mRuntimeHost->ExternalKeyingEnabled(), initFailureReason))
+	if (!mVideoIO->ConfigureOutput([this](const VideoIOCompletion& completion) { mVideoIOBridge->PlayoutFrameCompleted(completion); }, initFailureReason))
 	{
 		goto error;
 	}
@@ -151,13 +144,16 @@ bool OpenGLComposite::InitVideoIO()

 error:
 	if (!initFailureReason.empty())
-		MessageBoxA(NULL, initFailureReason.c_str(), "DeckLink initialization failed", MB_OK | MB_ICONERROR);
+		MessageBoxA(NULL, initFailureReason.c_str(), "Video I/O initialization failed", MB_OK | MB_ICONERROR);
 	mVideoIO->ReleaseResources();
 	return false;
 }

 void OpenGLComposite::paintGL()
 {
+	if (!mVideoIO)
+		return;
+
 	if (!TryEnterCriticalSection(&pMutex))
 	{
 		ValidateRect(hGLWnd, NULL);
@@ -187,21 +183,13 @@ void OpenGLComposite::resizeWindow(int width, int height)

 void OpenGLComposite::PublishVideoIOStatus(const std::string& statusMessage)
 {
-	if (!mRuntimeHost)
+	if (!mRuntimeHost || !mVideoIO)
 		return;

 	if (!statusMessage.empty())
 		mVideoIO->SetStatusMessage(statusMessage);

-	mRuntimeHost->SetVideoIOStatus(
-		"decklink",
-		mVideoIO->OutputModelName(),
-		mVideoIO->SupportsInternalKeying(),
-		mVideoIO->SupportsExternalKeying(),
-		mVideoIO->KeyerInterfaceAvailable(),
-		mRuntimeHost->ExternalKeyingEnabled(),
-		mVideoIO->ExternalKeyingActive(),
-		mVideoIO->StatusMessage());
+	mRuntimeHost->SetVideoIOStatus(mVideoIO->State());
 }

 bool OpenGLComposite::InitOpenGLState()
@@ -314,15 +302,35 @@ void OpenGLComposite::renderEffect()
 	}
 	else if (mRuntimeHost)
 	{
-		if (mRuntimeHost->TryGetLayerRenderStates(mVideoIO->InputFrameWidth(), mVideoIO->InputFrameHeight(), layerStates))
-		{
-			mCachedLayerRenderStates = layerStates;
-		}
-		else
+		const unsigned renderWidth = mVideoIO->InputFrameWidth();
+		const unsigned renderHeight = mVideoIO->InputFrameHeight();
+		const uint64_t renderStateVersion = mRuntimeHost->GetRenderStateVersion();
+		const bool renderStateCacheValid =
+			!mCachedLayerRenderStates.empty() &&
+			mCachedRenderStateVersion == renderStateVersion &&
+			mCachedRenderStateWidth == renderWidth &&
+			mCachedRenderStateHeight == renderHeight;
+
+		if (renderStateCacheValid)
 		{
 			layerStates = mCachedLayerRenderStates;
 			mRuntimeHost->RefreshDynamicRenderStateFields(layerStates);
 		}
+		else
+		{
+			if (mRuntimeHost->TryGetLayerRenderStates(renderWidth, renderHeight, layerStates))
+			{
+				mCachedLayerRenderStates = layerStates;
+				mCachedRenderStateVersion = renderStateVersion;
+				mCachedRenderStateWidth = renderWidth;
+				mCachedRenderStateHeight = renderHeight;
+			}
+			else
+			{
+				layerStates = mCachedLayerRenderStates;
+				mRuntimeHost->RefreshDynamicRenderStateFields(layerStates);
+			}
+		}
 	}
 	const unsigned historyCap = mRuntimeHost ? mRuntimeHost->GetMaxTemporalHistoryFrames() : 0;
 	mRenderPass->Render(
--- a/apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.h
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.h
@@ -39,8 +39,7 @@ public:
 	OpenGLComposite(HWND hWnd, HDC hDC, HGLRC hRC);
 	~OpenGLComposite();

-	bool InitDeckLink();
-	bool InitVideoIO();
+	bool InitializeVideoIO();
 	bool Start();
 	bool Stop();
 	bool ReloadShader();
@@ -87,6 +86,9 @@ private:
 	std::unique_ptr<ShaderBuildQueue>		mShaderBuildQueue;
 	std::unique_ptr<RuntimeServices>		mRuntimeServices;
 	std::vector<RuntimeRenderState>			mCachedLayerRenderStates;
+	uint64_t								mCachedRenderStateVersion = 0;
+	unsigned								mCachedRenderStateWidth = 0;
+	unsigned								mCachedRenderStateHeight = 0;
 	std::atomic<bool>						mUseCommittedLayerStates;
 	std::atomic<bool>						mScreenshotRequested;

--- a/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPass.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPass.cpp
@@ -45,7 +45,7 @@ void OpenGLRenderPass::Render(
 	}
 	else
 	{
-		const std::vector<RenderPassDescriptor> passes = BuildLayerPassDescriptors(layerStates, layerPrograms);
+		const std::vector<RenderPassDescriptor>& passes = BuildLayerPassDescriptors(layerStates, layerPrograms);
 		for (const RenderPassDescriptor& pass : passes)
 		{
 			RenderLayerPass(
@@ -71,9 +71,9 @@ void OpenGLRenderPass::RenderDecodePass(unsigned inputFrameWidth, unsigned input
 	glBindVertexArray(mRenderer.FullscreenVertexArray());
 	glUseProgram(mRenderer.DecodeProgram());

-	const GLint packedResolutionLocation = glGetUniformLocation(mRenderer.DecodeProgram(), "uPackedVideoResolution");
-	const GLint decodedResolutionLocation = glGetUniformLocation(mRenderer.DecodeProgram(), "uDecodedVideoResolution");
-	const GLint inputPixelFormatLocation = glGetUniformLocation(mRenderer.DecodeProgram(), "uInputPixelFormat");
+	const GLint packedResolutionLocation = mRenderer.DecodePackedResolutionLocation();
+	const GLint decodedResolutionLocation = mRenderer.DecodeDecodedResolutionLocation();
+	const GLint inputPixelFormatLocation = mRenderer.DecodeInputPixelFormatLocation();
 	if (packedResolutionLocation >= 0)
 		glUniform2f(packedResolutionLocation, static_cast<float>(captureTextureWidth), static_cast<float>(inputFrameHeight));
 	if (decodedResolutionLocation >= 0)
@@ -96,7 +96,8 @@ std::vector<RenderPassDescriptor> OpenGLRenderPass::BuildLayerPassDescriptors(
 	// Flatten the layer stack into concrete GL passes. A layer may now contain
 	// several shader passes, but the outer stack still sees one visible output
 	// per layer.
-	std::vector<RenderPassDescriptor> passes;
+	std::vector<RenderPassDescriptor>& passes = mPassScratch;
+	passes.clear();
 	const std::size_t passCount = layerStates.size() < layerPrograms.size() ? layerStates.size() : layerPrograms.size();
 	std::size_t descriptorCount = 0;
 	for (std::size_t index = 0; index < passCount; ++index)
--- a/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPass.h
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPass.h
@@ -56,4 +56,5 @@ private:

 	OpenGLRenderer& mRenderer;
 	ShaderTextureBindings mTextureBindings;
+	mutable std::vector<RenderPassDescriptor> mPassScratch;
 };
--- a/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.cpp
@@ -4,6 +4,8 @@
 #include "RuntimeHost.h"
 #include "VideoIOFormat.h"

+#include <cstring>
+
 #include <chrono>
 #include <gl/gl.h>

@@ -21,6 +23,11 @@ OpenGLRenderPipeline::OpenGLRenderPipeline(
 {
 }

+OpenGLRenderPipeline::~OpenGLRenderPipeline()
+{
+	ResetAsyncReadbackState();
+}
+
 bool OpenGLRenderPipeline::RenderFrame(const RenderPipelineFrameContext& context, VideoIOOutputFrame& outputFrame)
 {
 	const VideoIOState& state = context.videoState;
@@ -62,9 +69,9 @@ void OpenGLRenderPipeline::PackOutputFor10Bit(const VideoIOState& state)
 	glBindVertexArray(mRenderer.FullscreenVertexArray());
 	glUseProgram(mRenderer.OutputPackProgram());

-	const GLint outputResolutionLocation = glGetUniformLocation(mRenderer.OutputPackProgram(), "uOutputVideoResolution");
-	const GLint activeWordsLocation = glGetUniformLocation(mRenderer.OutputPackProgram(), "uActiveV210Words");
-	const GLint packFormatLocation = glGetUniformLocation(mRenderer.OutputPackProgram(), "uOutputPackFormat");
+	const GLint outputResolutionLocation = mRenderer.OutputPackResolutionLocation();
+	const GLint activeWordsLocation = mRenderer.OutputPackActiveWordsLocation();
+	const GLint packFormatLocation = mRenderer.OutputPackFormatLocation();
 	if (outputResolutionLocation >= 0)
 		glUniform2f(outputResolutionLocation, static_cast<float>(state.outputFrameSize.width), static_cast<float>(state.outputFrameSize.height));
 	if (activeWordsLocation >= 0)
@@ -78,18 +85,195 @@ void OpenGLRenderPipeline::PackOutputFor10Bit(const VideoIOState& state)
 	glBindTexture(GL_TEXTURE_2D, 0);
 }

-void OpenGLRenderPipeline::ReadOutputFrame(const VideoIOState& state, VideoIOOutputFrame& outputFrame)
+bool OpenGLRenderPipeline::EnsureAsyncReadbackBuffers(std::size_t requiredBytes)
 {
+	if (requiredBytes == 0)
+		return false;
+
+	if (mAsyncReadbackBytes == requiredBytes && mAsyncReadbackSlots[0].pixelPackBuffer != 0)
+		return true;
+
+	ResetAsyncReadbackState();
+	mAsyncReadbackBytes = requiredBytes;
+	for (AsyncReadbackSlot& slot : mAsyncReadbackSlots)
+	{
+		glGenBuffers(1, &slot.pixelPackBuffer);
+		glBindBuffer(GL_PIXEL_PACK_BUFFER, slot.pixelPackBuffer);
+		glBufferData(GL_PIXEL_PACK_BUFFER, static_cast<GLsizeiptr>(requiredBytes), nullptr, GL_STREAM_READ);
+		slot.sizeBytes = requiredBytes;
+		slot.inFlight = false;
+	}
+	glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+	mAsyncReadbackWriteIndex = 0;
+	mAsyncReadbackReadIndex = 0;
+	return true;
+}
+
+void OpenGLRenderPipeline::ResetAsyncReadbackState()
+{
+	FlushAsyncReadbackPipeline();
+	for (AsyncReadbackSlot& slot : mAsyncReadbackSlots)
+		slot.sizeBytes = 0;
+
+	if (mAsyncReadbackSlots[0].pixelPackBuffer != 0)
+	{
+		for (AsyncReadbackSlot& slot : mAsyncReadbackSlots)
+		{
+			if (slot.pixelPackBuffer != 0)
+			{
+				glDeleteBuffers(1, &slot.pixelPackBuffer);
+				slot.pixelPackBuffer = 0;
+			}
+		}
+	}
+
+	mAsyncReadbackWriteIndex = 0;
+	mAsyncReadbackReadIndex = 0;
+	mAsyncReadbackBytes = 0;
+}
+
+void OpenGLRenderPipeline::FlushAsyncReadbackPipeline()
+{
+	for (AsyncReadbackSlot& slot : mAsyncReadbackSlots)
+	{
+		if (slot.fence != nullptr)
+		{
+			glDeleteSync(slot.fence);
+			slot.fence = nullptr;
+		}
+		slot.inFlight = false;
+	}
+
+	mAsyncReadbackWriteIndex = 0;
+	mAsyncReadbackReadIndex = 0;
+}
+
+void OpenGLRenderPipeline::QueueAsyncReadback(const VideoIOState& state)
+{
+	const bool usePackedOutput = state.outputPixelFormat == VideoIOPixelFormat::V210 || state.outputPixelFormat == VideoIOPixelFormat::Yuva10;
+	const std::size_t requiredBytes = static_cast<std::size_t>(state.outputFrameRowBytes) * state.outputFrameSize.height;
+	const GLenum format = usePackedOutput ? GL_RGBA : GL_BGRA;
+	const GLenum type = usePackedOutput ? GL_UNSIGNED_BYTE : GL_UNSIGNED_INT_8_8_8_8_REV;
+	const GLuint framebuffer = usePackedOutput ? mRenderer.OutputPackFramebuffer() : mRenderer.OutputFramebuffer();
+	const GLsizei readWidth = static_cast<GLsizei>(usePackedOutput ? state.outputPackTextureWidth : state.outputFrameSize.width);
+	const GLsizei readHeight = static_cast<GLsizei>(state.outputFrameSize.height);
+
+	if (requiredBytes == 0)
+		return;
+
+	if (mAsyncReadbackBytes != requiredBytes
+		|| mAsyncReadbackFormat != format
+		|| mAsyncReadbackType != type
+		|| mAsyncReadbackFramebuffer != framebuffer)
+	{
+		mAsyncReadbackFormat = format;
+		mAsyncReadbackType = type;
+		mAsyncReadbackFramebuffer = framebuffer;
+		if (!EnsureAsyncReadbackBuffers(requiredBytes))
+			return;
+	}
+
+	AsyncReadbackSlot& slot = mAsyncReadbackSlots[mAsyncReadbackWriteIndex];
+	if (slot.fence != nullptr)
+	{
+		glDeleteSync(slot.fence);
+		slot.fence = nullptr;
+	}
+
 	glPixelStorei(GL_PACK_ALIGNMENT, 4);
 	glPixelStorei(GL_PACK_ROW_LENGTH, 0);
-	if (state.outputPixelFormat == VideoIOPixelFormat::V210 || state.outputPixelFormat == VideoIOPixelFormat::Yuva10)
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, framebuffer);
+	glBindBuffer(GL_PIXEL_PACK_BUFFER, slot.pixelPackBuffer);
+	glBufferData(GL_PIXEL_PACK_BUFFER, static_cast<GLsizeiptr>(requiredBytes), nullptr, GL_STREAM_READ);
+	glReadPixels(0, 0, readWidth, readHeight, format, type, nullptr);
+	slot.fence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
+	slot.inFlight = slot.fence != nullptr;
+	glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+
+	mAsyncReadbackWriteIndex = (mAsyncReadbackWriteIndex + 1) % mAsyncReadbackSlots.size();
+}
+
+bool OpenGLRenderPipeline::TryConsumeAsyncReadback(VideoIOOutputFrame& outputFrame, GLuint64 timeoutNanoseconds)
+{
+	if (mAsyncReadbackBytes == 0 || outputFrame.bytes == nullptr)
+		return false;
+
+	AsyncReadbackSlot& slot = mAsyncReadbackSlots[mAsyncReadbackReadIndex];
+	if (!slot.inFlight || slot.fence == nullptr || slot.pixelPackBuffer == 0)
+		return false;
+
+	const GLenum waitFlags = timeoutNanoseconds > 0 ? GL_SYNC_FLUSH_COMMANDS_BIT : 0;
+	const GLenum waitResult = glClientWaitSync(slot.fence, waitFlags, timeoutNanoseconds);
+	if (waitResult != GL_ALREADY_SIGNALED && waitResult != GL_CONDITION_SATISFIED)
+		return false;
+
+	glDeleteSync(slot.fence);
+	slot.fence = nullptr;
+
+	glBindBuffer(GL_PIXEL_PACK_BUFFER, slot.pixelPackBuffer);
+	void* mappedBytes = glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY);
+	if (mappedBytes == nullptr)
+	{
+		glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+		slot.inFlight = false;
+		mAsyncReadbackReadIndex = (mAsyncReadbackReadIndex + 1) % mAsyncReadbackSlots.size();
+		return false;
+	}
+
+	std::memcpy(outputFrame.bytes, mappedBytes, slot.sizeBytes);
+	glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
+	glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+
+	slot.inFlight = false;
+	mAsyncReadbackReadIndex = (mAsyncReadbackReadIndex + 1) % mAsyncReadbackSlots.size();
+	CacheOutputFrame(outputFrame);
+	return true;
+}
+
+void OpenGLRenderPipeline::CacheOutputFrame(const VideoIOOutputFrame& outputFrame)
+{
+	if (outputFrame.bytes == nullptr || outputFrame.height == 0 || outputFrame.rowBytes <= 0)
+		return;
+
+	const std::size_t byteCount = static_cast<std::size_t>(outputFrame.rowBytes) * outputFrame.height;
+	mCachedOutputFrame.resize(byteCount);
+	std::memcpy(mCachedOutputFrame.data(), outputFrame.bytes, byteCount);
+}
+
+void OpenGLRenderPipeline::ReadOutputFrameSynchronously(const VideoIOState& state, void* destinationBytes)
+{
+	const bool usePackedOutput = state.outputPixelFormat == VideoIOPixelFormat::V210 || state.outputPixelFormat == VideoIOPixelFormat::Yuva10;
+
+	glPixelStorei(GL_PACK_ALIGNMENT, 4);
+	glPixelStorei(GL_PACK_ROW_LENGTH, 0);
+	if (usePackedOutput)
 	{
 		glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.OutputPackFramebuffer());
-		glReadPixels(0, 0, state.outputPackTextureWidth, state.outputFrameSize.height, GL_RGBA, GL_UNSIGNED_BYTE, outputFrame.bytes);
+		glReadPixels(0, 0, state.outputPackTextureWidth, state.outputFrameSize.height, GL_RGBA, GL_UNSIGNED_BYTE, destinationBytes);
 	}
 	else
 	{
 		glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.OutputFramebuffer());
-		glReadPixels(0, 0, state.outputFrameSize.width, state.outputFrameSize.height, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, outputFrame.bytes);
+		glReadPixels(0, 0, state.outputFrameSize.width, state.outputFrameSize.height, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, destinationBytes);
 	}
 }
+
+void OpenGLRenderPipeline::ReadOutputFrame(const VideoIOState& state, VideoIOOutputFrame& outputFrame)
+{
+	if (TryConsumeAsyncReadback(outputFrame, 500000))
+	{
+		QueueAsyncReadback(state);
+		return;
+	}
+
+	// If async readback misses the playout deadline, prefer a fresh synchronous
+	// frame over reusing stale cached output, then restart the async pipeline.
+	if (outputFrame.bytes != nullptr)
+	{
+		ReadOutputFrameSynchronously(state, outputFrame.bytes);
+		CacheOutputFrame(outputFrame);
+	}
+
+	FlushAsyncReadbackPipeline();
+	QueueAsyncReadback(state);
+}
--- a/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.h
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLRenderPipeline.h
@@ -1,8 +1,11 @@
 #pragma once

+#include "GLExtensions.h"
 #include "VideoIOTypes.h"

+#include <array>
 #include <functional>
+#include <vector>

 class OpenGLRenderer;
 class RuntimeHost;
@@ -26,10 +29,26 @@ public:
 		RenderEffectCallback renderEffect,
 		OutputReadyCallback outputReady,
 		PaintCallback paint);
+	~OpenGLRenderPipeline();

 	bool RenderFrame(const RenderPipelineFrameContext& context, VideoIOOutputFrame& outputFrame);

 private:
+	struct AsyncReadbackSlot
+	{
+		GLuint pixelPackBuffer = 0;
+		GLsync fence = nullptr;
+		std::size_t sizeBytes = 0;
+		bool inFlight = false;
+	};
+
+	bool EnsureAsyncReadbackBuffers(std::size_t requiredBytes);
+	void ResetAsyncReadbackState();
+	void FlushAsyncReadbackPipeline();
+	void QueueAsyncReadback(const VideoIOState& state);
+	bool TryConsumeAsyncReadback(VideoIOOutputFrame& outputFrame, GLuint64 timeoutNanoseconds);
+	void CacheOutputFrame(const VideoIOOutputFrame& outputFrame);
+	void ReadOutputFrameSynchronously(const VideoIOState& state, void* destinationBytes);
 	void PackOutputFor10Bit(const VideoIOState& state);
 	void ReadOutputFrame(const VideoIOState& state, VideoIOOutputFrame& outputFrame);

@@ -38,4 +57,12 @@ private:
 	RenderEffectCallback mRenderEffect;
 	OutputReadyCallback mOutputReady;
 	PaintCallback mPaint;
+	std::array<AsyncReadbackSlot, 3> mAsyncReadbackSlots;
+	std::size_t mAsyncReadbackWriteIndex = 0;
+	std::size_t mAsyncReadbackReadIndex = 0;
+	std::size_t mAsyncReadbackBytes = 0;
+	GLenum mAsyncReadbackFormat = GL_BGRA;
+	GLenum mAsyncReadbackType = GL_UNSIGNED_INT_8_8_8_8_REV;
+	GLuint mAsyncReadbackFramebuffer = 0;
+	std::vector<unsigned char> mCachedOutputFrame;
 };
--- a/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.cpp
@@ -7,7 +7,7 @@
 #include <gl/gl.h>

 OpenGLVideoIOBridge::OpenGLVideoIOBridge(
-	VideoIODevice& videoIO,
+	VideoIODevice* videoIO,
 	OpenGLRenderer& renderer,
 	OpenGLRenderPipeline& renderPipeline,
 	RuntimeHost& runtimeHost,
@@ -24,6 +24,11 @@ OpenGLVideoIOBridge::OpenGLVideoIOBridge(
 {
 }

+void OpenGLVideoIOBridge::SetVideoIODevice(VideoIODevice* videoIO)
+{
+	mVideoIO = videoIO;
+}
+
 void OpenGLVideoIOBridge::RecordFramePacing(VideoIOCompletionResult completionResult)
 {
 	const auto now = std::chrono::steady_clock::now();
@@ -57,7 +62,10 @@ void OpenGLVideoIOBridge::RecordFramePacing(VideoIOCompletionResult completionRe

 void OpenGLVideoIOBridge::VideoFrameArrived(const VideoIOFrame& inputFrame)
 {
-	const VideoIOState& state = mVideoIO.State();
+	if (mVideoIO == nullptr)
+		return;
+
+	const VideoIOState& state = mVideoIO->State();
 	mRuntimeHost.TrySetSignalStatus(!inputFrame.hasNoInputSource, state.inputFrameSize.width, state.inputFrameSize.height, state.inputDisplayModeName);

 	if (inputFrame.hasNoInputSource || inputFrame.bytes == nullptr)
@@ -91,17 +99,20 @@ void OpenGLVideoIOBridge::VideoFrameArrived(const VideoIOFrame& inputFrame)

 void OpenGLVideoIOBridge::PlayoutFrameCompleted(const VideoIOCompletion& completion)
 {
+	if (mVideoIO == nullptr)
+		return;
+
 	RecordFramePacing(completion.result);

 	EnterCriticalSection(&mMutex);

 	VideoIOOutputFrame outputFrame;
-	if (!mVideoIO.BeginOutputFrame(outputFrame))
+	if (!mVideoIO->BeginOutputFrame(outputFrame))
 	{
 		LeaveCriticalSection(&mMutex);
 		return;
 	}
-	const VideoIOState& state = mVideoIO.State();
+	const VideoIOState& state = mVideoIO->State();
 	RenderPipelineFrameContext frameContext;
 	frameContext.videoState = state;
 	frameContext.completion = completion;
@@ -111,12 +122,12 @@ void OpenGLVideoIOBridge::PlayoutFrameCompleted(const VideoIOCompletion& complet

 	mRenderPipeline.RenderFrame(frameContext, outputFrame);

-	mVideoIO.EndOutputFrame(outputFrame);
+	mVideoIO->EndOutputFrame(outputFrame);

-	mVideoIO.AccountForCompletionResult(completion.result);
+	mVideoIO->AccountForCompletionResult(completion.result);

 	// Schedule the next frame for playout
-	mVideoIO.ScheduleOutputFrame(outputFrame);
+	mVideoIO->ScheduleOutputFrame(outputFrame);

 	wglMakeCurrent(NULL, NULL);

--- a/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.h
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/pipeline/OpenGLVideoIOBridge.h
@@ -13,7 +13,7 @@ class OpenGLVideoIOBridge
 {
 public:
 	OpenGLVideoIOBridge(
-		VideoIODevice& videoIO,
+		VideoIODevice* videoIO,
 		OpenGLRenderer& renderer,
 		OpenGLRenderPipeline& renderPipeline,
 		RuntimeHost& runtimeHost,
@@ -21,13 +21,15 @@ public:
 		HDC hdc,
 		HGLRC hglrc);

+	void SetVideoIODevice(VideoIODevice* videoIO);
+
 	void VideoFrameArrived(const VideoIOFrame& inputFrame);
 	void PlayoutFrameCompleted(const VideoIOCompletion& completion);

 private:
 	void RecordFramePacing(VideoIOCompletionResult completionResult);

-	VideoIODevice& mVideoIO;
+	VideoIODevice* mVideoIO;
 	OpenGLRenderer& mRenderer;
 	OpenGLRenderPipeline& mRenderPipeline;
 	RuntimeHost& mRuntimeHost;
--- a/apps/LoopThroughWithOpenGLCompositing/gl/renderer/GLExtensions.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/renderer/GLExtensions.cpp
@@ -62,6 +62,8 @@ PFNGLGENBUFFERSPROC glGenBuffers;
 PFNGLDELETEBUFFERSPROC glDeleteBuffers;
 PFNGLBINDBUFFERPROC glBindBuffer;
 PFNGLBUFFERDATAPROC glBufferData;
+PFNGLMAPBUFFERPROC glMapBuffer;
+PFNGLUNMAPBUFFERPROC glUnmapBuffer;
 PFNGLBUFFERSUBDATAPROC glBufferSubData;
 PFNGLBINDBUFFERBASEPROC glBindBufferBase;
 PFNGLACTIVETEXTUREPROC glActiveTexture;
@@ -131,6 +133,8 @@ bool ResolveGLExtensions()
 	glDeleteBuffers = (PFNGLDELETEBUFFERSPROC) wglGetProcAddress("glDeleteBuffers");
 	glBindBuffer = (PFNGLBINDBUFFERPROC) wglGetProcAddress("glBindBuffer");
 	glBufferData = (PFNGLBUFFERDATAPROC) wglGetProcAddress("glBufferData");
+	glMapBuffer = (PFNGLMAPBUFFERPROC) wglGetProcAddress("glMapBuffer");
+	glUnmapBuffer = (PFNGLUNMAPBUFFERPROC) wglGetProcAddress("glUnmapBuffer");
 	glBufferSubData = (PFNGLBUFFERSUBDATAPROC) wglGetProcAddress("glBufferSubData");
 	glBindBufferBase = (PFNGLBINDBUFFERBASEPROC) wglGetProcAddress("glBindBufferBase");
 	glActiveTexture = (PFNGLACTIVETEXTUREPROC) wglGetProcAddress("glActiveTexture");
@@ -176,6 +180,8 @@ bool ResolveGLExtensions()
 			&& glDeleteBuffers
 			&& glBindBuffer
 			&& glBufferData
+			&& glMapBuffer
+			&& glUnmapBuffer
 			&& glBufferSubData
 			&& glBindBufferBase
 			&& glActiveTexture
--- a/apps/LoopThroughWithOpenGLCompositing/gl/renderer/GLExtensions.h
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/renderer/GLExtensions.h
@@ -89,6 +89,11 @@
 #define GL_EXTERNAL_VIRTUAL_MEMORY_BUFFER_AMD	0x9160
 #define GL_SYNC_GPU_COMMANDS_COMPLETE			0x9117
 #define GL_SYNC_FLUSH_COMMANDS_BIT				0x00000001
+#define GL_ALREADY_SIGNALED						0x911A
+#define GL_TIMEOUT_EXPIRED						0x911B
+#define GL_CONDITION_SATISFIED					0x911C
+#define GL_WAIT_FAILED							0x911D
+#define GL_READ_ONLY							0x88B8

 typedef struct __GLsync *GLsync;
 typedef unsigned __int64 GLuint64;
@@ -100,6 +105,8 @@ typedef void (APIENTRYP PFNGLBINDBUFFERPROC) (GLenum target, GLuint buffer);
 typedef void (APIENTRYP PFNGLDELETEBUFFERSPROC) (GLsizei n, const GLuint *buffers);
 typedef void (APIENTRYP PFNGLGENBUFFERSPROC) (GLsizei n, GLuint *buffers);
 typedef void (APIENTRYP PFNGLBUFFERDATAPROC) (GLenum target, GLsizeiptr size, const GLvoid *data, GLenum usage);
+typedef GLvoid* (APIENTRYP PFNGLMAPBUFFERPROC) (GLenum target, GLenum access);
+typedef GLboolean (APIENTRYP PFNGLUNMAPBUFFERPROC) (GLenum target);
 typedef void (APIENTRYP PFNGLATTACHSHADERPROC) (GLuint program, GLuint shader);
 typedef void (APIENTRYP PFNGLCOMPILESHADERPROC) (GLuint shader);
 typedef GLuint (APIENTRYP PFNGLCREATEPROGRAMPROC) (void);
@@ -159,6 +166,8 @@ extern PFNGLGENBUFFERSPROC glGenBuffers;
 extern PFNGLDELETEBUFFERSPROC glDeleteBuffers;
 extern PFNGLBINDBUFFERPROC glBindBuffer;
 extern PFNGLBUFFERDATAPROC glBufferData;
+extern PFNGLMAPBUFFERPROC glMapBuffer;
+extern PFNGLUNMAPBUFFERPROC glUnmapBuffer;
 extern PFNGLBUFFERSUBDATAPROC glBufferSubData;
 extern PFNGLBINDBUFFERBASEPROC glBindBufferBase;
 extern PFNGLACTIVETEXTUREPROC glActiveTexture;
--- a/apps/LoopThroughWithOpenGLCompositing/gl/renderer/OpenGLRenderer.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/renderer/OpenGLRenderer.cpp
@@ -71,6 +71,9 @@ void OpenGLRenderer::SetDecodeShaderProgram(GLuint program, GLuint vertexShader,
 	mDecodeProgram = program;
 	mDecodeVertexShader = vertexShader;
 	mDecodeFragmentShader = fragmentShader;
+	mDecodePackedResolutionLocation = program != 0 ? glGetUniformLocation(program, "uPackedVideoResolution") : -1;
+	mDecodeDecodedResolutionLocation = program != 0 ? glGetUniformLocation(program, "uDecodedVideoResolution") : -1;
+	mDecodeInputPixelFormatLocation = program != 0 ? glGetUniformLocation(program, "uInputPixelFormat") : -1;
 }

 void OpenGLRenderer::SetOutputPackShaderProgram(GLuint program, GLuint vertexShader, GLuint fragmentShader)
@@ -78,6 +81,9 @@ void OpenGLRenderer::SetOutputPackShaderProgram(GLuint program, GLuint vertexSha
 	mOutputPackProgram = program;
 	mOutputPackVertexShader = vertexShader;
 	mOutputPackFragmentShader = fragmentShader;
+	mOutputPackResolutionLocation = program != 0 ? glGetUniformLocation(program, "uOutputVideoResolution") : -1;
+	mOutputPackActiveWordsLocation = program != 0 ? glGetUniformLocation(program, "uActiveV210Words") : -1;
+	mOutputPackFormatLocation = program != 0 ? glGetUniformLocation(program, "uOutputPackFormat") : -1;
 }

 bool OpenGLRenderer::ReserveTemporaryRenderTargets(std::size_t count, unsigned width, unsigned height, std::string& error)
@@ -217,6 +223,9 @@ void OpenGLRenderer::DestroyDecodeShaderProgram()
 		glDeleteProgram(mDecodeProgram);
 		mDecodeProgram = 0;
 	}
+	mDecodePackedResolutionLocation = -1;
+	mDecodeDecodedResolutionLocation = -1;
+	mDecodeInputPixelFormatLocation = -1;

 	if (mDecodeFragmentShader != 0)
 	{
@@ -238,6 +247,9 @@ void OpenGLRenderer::DestroyOutputPackShaderProgram()
 		glDeleteProgram(mOutputPackProgram);
 		mOutputPackProgram = 0;
 	}
+	mOutputPackResolutionLocation = -1;
+	mOutputPackActiveWordsLocation = -1;
+	mOutputPackFormatLocation = -1;

 	if (mOutputPackFragmentShader != 0)
 	{
--- a/apps/LoopThroughWithOpenGLCompositing/gl/renderer/OpenGLRenderer.h
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/renderer/OpenGLRenderer.h
@@ -70,6 +70,12 @@ public:
 	GLuint GlobalParamsUBO() const { return mGlobalParamsUBO; }
 	GLuint DecodeProgram() const { return mDecodeProgram; }
 	GLuint OutputPackProgram() const { return mOutputPackProgram; }
+	GLint DecodePackedResolutionLocation() const { return mDecodePackedResolutionLocation; }
+	GLint DecodeDecodedResolutionLocation() const { return mDecodeDecodedResolutionLocation; }
+	GLint DecodeInputPixelFormatLocation() const { return mDecodeInputPixelFormatLocation; }
+	GLint OutputPackResolutionLocation() const { return mOutputPackResolutionLocation; }
+	GLint OutputPackActiveWordsLocation() const { return mOutputPackActiveWordsLocation; }
+	GLint OutputPackFormatLocation() const { return mOutputPackFormatLocation; }
 	GLsizeiptr GlobalParamsUBOSize() const { return mGlobalParamsUBOSize; }
 	void SetGlobalParamsUBOSize(GLsizeiptr size) { mGlobalParamsUBOSize = size; }
 	void ReplaceLayerPrograms(std::vector<LayerProgram>& newPrograms) { mLayerPrograms.swap(newPrograms); }
@@ -101,9 +107,15 @@ private:
 	GLuint mDecodeProgram = 0;
 	GLuint mDecodeVertexShader = 0;
 	GLuint mDecodeFragmentShader = 0;
+	GLint mDecodePackedResolutionLocation = -1;
+	GLint mDecodeDecodedResolutionLocation = -1;
+	GLint mDecodeInputPixelFormatLocation = -1;
 	GLuint mOutputPackProgram = 0;
 	GLuint mOutputPackVertexShader = 0;
 	GLuint mOutputPackFragmentShader = 0;
+	GLint mOutputPackResolutionLocation = -1;
+	GLint mOutputPackActiveWordsLocation = -1;
+	GLint mOutputPackFormatLocation = -1;
 	GLsizeiptr mGlobalParamsUBOSize = 0;
 	int mViewWidth = 0;
 	int mViewHeight = 0;
--- a/apps/LoopThroughWithOpenGLCompositing/gl/shader/GlobalParamsBuffer.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/shader/GlobalParamsBuffer.cpp
@@ -12,7 +12,8 @@ GlobalParamsBuffer::GlobalParamsBuffer(OpenGLRenderer& renderer) :

 bool GlobalParamsBuffer::Update(const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength)
 {
-	std::vector<unsigned char> buffer;
+	std::vector<unsigned char>& buffer = mScratchBuffer;
+	buffer.clear();
 	buffer.reserve(512);

 	AppendStd140Float(buffer, static_cast<float>(state.timeSeconds));
--- a/apps/LoopThroughWithOpenGLCompositing/gl/shader/GlobalParamsBuffer.h
+++ b/apps/LoopThroughWithOpenGLCompositing/gl/shader/GlobalParamsBuffer.h
@@ -3,6 +3,8 @@
 #include "OpenGLRenderer.h"
 #include "ShaderTypes.h"

+#include <vector>
+
 class GlobalParamsBuffer
 {
 public:
@@ -12,4 +14,5 @@ public:

 private:
 	OpenGLRenderer& mRenderer;
+	std::vector<unsigned char> mScratchBuffer;
 };
--- a/apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeHost.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeHost.cpp
@@ -841,6 +841,8 @@ bool RuntimeHost::PollFileChanges(bool& registryChanged, bool& reloadRequested,
 		}

 		reloadRequested = mReloadRequested;
+		if (registryChanged || reloadRequested)
+			MarkRenderStateDirtyLocked();
 		return true;
 	}
 	catch (const std::exception& exception)
@@ -884,6 +886,7 @@ bool RuntimeHost::AddLayer(const std::string& shaderId, std::string& error)
 	EnsureLayerDefaultsLocked(layer, shaderIt->second);
 	mPersistentState.layers.push_back(layer);
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }

@@ -900,6 +903,7 @@ bool RuntimeHost::RemoveLayer(const std::string& layerId, std::string& error)

 	mPersistentState.layers.erase(it);
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }

@@ -921,6 +925,7 @@ bool RuntimeHost::MoveLayer(const std::string& layerId, int direction, std::stri

 	std::swap(mPersistentState.layers[index], mPersistentState.layers[newIndex]);
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }

@@ -949,6 +954,7 @@ bool RuntimeHost::MoveLayerToIndex(const std::string& layerId, std::size_t targe
 	mPersistentState.layers.erase(mPersistentState.layers.begin() + static_cast<std::ptrdiff_t>(sourceIndex));
 	mPersistentState.layers.insert(mPersistentState.layers.begin() + static_cast<std::ptrdiff_t>(targetIndex), movedLayer);
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }

@@ -964,6 +970,7 @@ bool RuntimeHost::SetLayerBypass(const std::string& layerId, bool bypassed, std:

 	layer->bypass = bypassed;
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }

@@ -988,6 +995,7 @@ bool RuntimeHost::SetLayerShader(const std::string& layerId, const std::string&
 	layer->parameterValues.clear();
 	EnsureLayerDefaultsLocked(*layer, shaderIt->second);
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }

@@ -1024,6 +1032,7 @@ bool RuntimeHost::UpdateLayerParameter(const std::string& layerId, const std::st
 		const double previousCount = value.numberValues.empty() ? 0.0 : value.numberValues[0];
 		const double triggerTime = std::chrono::duration_cast<std::chrono::duration<double>>(std::chrono::steady_clock::now() - mStartTime).count();
 		value.numberValues = { previousCount + 1.0, triggerTime };
+		MarkRenderStateDirtyLocked();
 		return true;
 	}

@@ -1032,6 +1041,7 @@ bool RuntimeHost::UpdateLayerParameter(const std::string& layerId, const std::st
 		return false;

 	layer->parameterValues[parameterId] = normalized;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }

@@ -1079,6 +1089,7 @@ bool RuntimeHost::UpdateLayerParameterByControlKey(const std::string& layerKey,
 		const double previousCount = value.numberValues.empty() ? 0.0 : value.numberValues[0];
 		const double triggerTime = std::chrono::duration_cast<std::chrono::duration<double>>(std::chrono::steady_clock::now() - mStartTime).count();
 		value.numberValues = { previousCount + 1.0, triggerTime };
+		MarkRenderStateDirtyLocked();
 		return true;
 	}

@@ -1087,6 +1098,7 @@ bool RuntimeHost::UpdateLayerParameterByControlKey(const std::string& layerKey,
 		return false;

 	matchedLayer->parameterValues[parameterIt->id] = normalized;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }

@@ -1110,6 +1122,7 @@ bool RuntimeHost::ResetLayerParameters(const std::string& layerId, std::string&

 	layer->parameterValues.clear();
 	EnsureLayerDefaultsLocked(*layer, shaderIt->second);
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }

@@ -1169,6 +1182,7 @@ bool RuntimeHost::LoadStackPreset(const std::string& presetName, std::string& er

 	mPersistentState.layers = nextLayers;
 	mReloadRequested = true;
+	MarkRenderStateDirtyLocked();
 	return SavePersistentState(error);
 }

@@ -1197,31 +1211,37 @@ bool RuntimeHost::TrySetSignalStatus(bool hasSignal, unsigned width, unsigned he

 void RuntimeHost::SetSignalStatusLocked(bool hasSignal, unsigned width, unsigned height, const std::string& modeName)
 {
+	const bool changed = mHasSignal != hasSignal ||
+		mSignalWidth != width ||
+		mSignalHeight != height ||
+		mSignalModeName != modeName;
 	mHasSignal = hasSignal;
 	mSignalWidth = width;
 	mSignalHeight = height;
 	mSignalModeName = modeName;
+	if (changed)
+		MarkRenderStateDirtyLocked();
 }

-void RuntimeHost::SetDeckLinkOutputStatus(const std::string& modelName, bool supportsInternalKeying, bool supportsExternalKeying,
-	bool keyerInterfaceAvailable, bool externalKeyingRequested, bool externalKeyingActive, const std::string& statusMessage)
+void RuntimeHost::MarkRenderStateDirtyLocked()
 {
-	SetVideoIOStatus("decklink", modelName, supportsInternalKeying, supportsExternalKeying, keyerInterfaceAvailable,
-		externalKeyingRequested, externalKeyingActive, statusMessage);
+	mRenderStateVersion.fetch_add(1, std::memory_order_relaxed);
 }

-void RuntimeHost::SetVideoIOStatus(const std::string& backendName, const std::string& modelName, bool supportsInternalKeying, bool supportsExternalKeying,
-	bool keyerInterfaceAvailable, bool externalKeyingRequested, bool externalKeyingActive, const std::string& statusMessage)
+void RuntimeHost::SetVideoIOStatus(const VideoIOState& state)
 {
 	std::lock_guard<std::mutex> lock(mMutex);
-	mDeckLinkOutputStatus.backendName = backendName;
-	mDeckLinkOutputStatus.modelName = modelName;
-	mDeckLinkOutputStatus.supportsInternalKeying = supportsInternalKeying;
-	mDeckLinkOutputStatus.supportsExternalKeying = supportsExternalKeying;
-	mDeckLinkOutputStatus.keyerInterfaceAvailable = keyerInterfaceAvailable;
-	mDeckLinkOutputStatus.externalKeyingRequested = externalKeyingRequested;
-	mDeckLinkOutputStatus.externalKeyingActive = externalKeyingActive;
-	mDeckLinkOutputStatus.statusMessage = statusMessage;
+	mVideoIOStatus.backendId = state.backendId;
+	mVideoIOStatus.deviceName = state.deviceName;
+	mVideoIOStatus.capabilities = state.capabilities;
+	mVideoIOStatus.hasInputDevice = state.hasInputDevice;
+	mVideoIOStatus.hasInputSource = state.hasInputSource;
+	mVideoIOStatus.inputDisplayModeName = state.inputDisplayModeName;
+	mVideoIOStatus.outputDisplayModeName = state.outputDisplayModeName;
+	mVideoIOStatus.externalKeyingRequested = state.externalKeyingRequested;
+	mVideoIOStatus.externalKeyingActive = state.externalKeyingActive;
+	mVideoIOStatus.statusMessage = state.statusMessage;
+	mVideoIOStatus.formatStatusMessage = state.formatStatusMessage;
 }

 void RuntimeHost::SetPerformanceStats(double frameBudgetMilliseconds, double renderMilliseconds)
@@ -1456,61 +1476,67 @@ bool RuntimeHost::LoadConfig(std::string& error)
 		const double configuredValue = maxTemporalHistoryFramesValue->asNumber(static_cast<double>(mConfig.maxTemporalHistoryFrames));
 		mConfig.maxTemporalHistoryFrames = configuredValue <= 0.0 ? 0u : static_cast<unsigned>(configuredValue);
 	}
+	if (const JsonValue* videoBackendValue = configJson.find("videoBackend"))
+	{
+		VideoIOBackendId backendId = mConfig.videoIO.backendId;
+		if (videoBackendValue->isString() && ParseVideoIOBackendId(videoBackendValue->asString(), backendId))
+			mConfig.videoIO.backendId = backendId;
+	}
 	if (const JsonValue* enableExternalKeyingValue = configJson.find("enableExternalKeying"))
-		mConfig.enableExternalKeying = enableExternalKeyingValue->asBoolean(mConfig.enableExternalKeying);
+		mConfig.videoIO.externalKeyingEnabled = enableExternalKeyingValue->asBoolean(mConfig.videoIO.externalKeyingEnabled);
 	if (const JsonValue* videoFormatValue = configJson.find("videoFormat"))
 	{
 		if (videoFormatValue->isString() && !videoFormatValue->asString().empty())
 		{
-			mConfig.inputVideoFormat = videoFormatValue->asString();
-			mConfig.outputVideoFormat = videoFormatValue->asString();
+			mConfig.videoIO.inputMode.videoFormat = videoFormatValue->asString();
+			mConfig.videoIO.outputMode.videoFormat = videoFormatValue->asString();
 		}
 	}
 	if (const JsonValue* frameRateValue = configJson.find("frameRate"))
 	{
 		if (frameRateValue->isString() && !frameRateValue->asString().empty())
 		{
-			mConfig.inputFrameRate = frameRateValue->asString();
-			mConfig.outputFrameRate = frameRateValue->asString();
+			mConfig.videoIO.inputMode.frameRate = frameRateValue->asString();
+			mConfig.videoIO.outputMode.frameRate = frameRateValue->asString();
 		}
 		else if (frameRateValue->isNumber())
 		{
 			std::ostringstream stream;
 			stream << frameRateValue->asNumber();
-			mConfig.inputFrameRate = stream.str();
-			mConfig.outputFrameRate = stream.str();
+			mConfig.videoIO.inputMode.frameRate = stream.str();
+			mConfig.videoIO.outputMode.frameRate = stream.str();
 		}
 	}
 	if (const JsonValue* inputVideoFormatValue = configJson.find("inputVideoFormat"))
 	{
 		if (inputVideoFormatValue->isString() && !inputVideoFormatValue->asString().empty())
-			mConfig.inputVideoFormat = inputVideoFormatValue->asString();
+			mConfig.videoIO.inputMode.videoFormat = inputVideoFormatValue->asString();
 	}
 	if (const JsonValue* inputFrameRateValue = configJson.find("inputFrameRate"))
 	{
 		if (inputFrameRateValue->isString() && !inputFrameRateValue->asString().empty())
-			mConfig.inputFrameRate = inputFrameRateValue->asString();
+			mConfig.videoIO.inputMode.frameRate = inputFrameRateValue->asString();
 		else if (inputFrameRateValue->isNumber())
 		{
 			std::ostringstream stream;
 			stream << inputFrameRateValue->asNumber();
-			mConfig.inputFrameRate = stream.str();
+			mConfig.videoIO.inputMode.frameRate = stream.str();
 		}
 	}
 	if (const JsonValue* outputVideoFormatValue = configJson.find("outputVideoFormat"))
 	{
 		if (outputVideoFormatValue->isString() && !outputVideoFormatValue->asString().empty())
-			mConfig.outputVideoFormat = outputVideoFormatValue->asString();
+			mConfig.videoIO.outputMode.videoFormat = outputVideoFormatValue->asString();
 	}
 	if (const JsonValue* outputFrameRateValue = configJson.find("outputFrameRate"))
 	{
 		if (outputFrameRateValue->isString() && !outputFrameRateValue->asString().empty())
-			mConfig.outputFrameRate = outputFrameRateValue->asString();
+			mConfig.videoIO.outputMode.frameRate = outputFrameRateValue->asString();
 		else if (outputFrameRateValue->isNumber())
 		{
 			std::ostringstream stream;
 			stream << outputFrameRateValue->asNumber();
-			mConfig.outputFrameRate = stream.str();
+			mConfig.videoIO.outputMode.frameRate = stream.str();
 		}
 	}

@@ -1674,6 +1700,8 @@ bool RuntimeHost::ScanShaderPackages(std::string& error)
 			++it;
 	}

+	MarkRenderStateDirtyLocked();
+
 	return true;
 }

@@ -1840,11 +1868,12 @@ JsonValue RuntimeHost::BuildStateValue() const
 	app.set("oscPort", JsonValue(static_cast<double>(mConfig.oscPort)));
 	app.set("autoReload", JsonValue(mAutoReloadEnabled));
 	app.set("maxTemporalHistoryFrames", JsonValue(static_cast<double>(mConfig.maxTemporalHistoryFrames)));
-	app.set("enableExternalKeying", JsonValue(mConfig.enableExternalKeying));
-	app.set("inputVideoFormat", JsonValue(mConfig.inputVideoFormat));
-	app.set("inputFrameRate", JsonValue(mConfig.inputFrameRate));
-	app.set("outputVideoFormat", JsonValue(mConfig.outputVideoFormat));
-	app.set("outputFrameRate", JsonValue(mConfig.outputFrameRate));
+	app.set("videoBackend", JsonValue(VideoIOBackendName(mConfig.videoIO.backendId)));
+	app.set("enableExternalKeying", JsonValue(mConfig.videoIO.externalKeyingEnabled));
+	app.set("inputVideoFormat", JsonValue(mConfig.videoIO.inputMode.videoFormat));
+	app.set("inputFrameRate", JsonValue(mConfig.videoIO.inputMode.frameRate));
+	app.set("outputVideoFormat", JsonValue(mConfig.videoIO.outputMode.videoFormat));
+	app.set("outputFrameRate", JsonValue(mConfig.videoIO.outputMode.frameRate));
 	root.set("app", app);

 	JsonValue runtime = JsonValue::MakeObject();
@@ -1860,25 +1889,22 @@ JsonValue RuntimeHost::BuildStateValue() const
 	video.set("modeName", JsonValue(mSignalModeName));
 	root.set("video", video);

-	JsonValue deckLink = JsonValue::MakeObject();
-	deckLink.set("modelName", JsonValue(mDeckLinkOutputStatus.modelName));
-	deckLink.set("supportsInternalKeying", JsonValue(mDeckLinkOutputStatus.supportsInternalKeying));
-	deckLink.set("supportsExternalKeying", JsonValue(mDeckLinkOutputStatus.supportsExternalKeying));
-	deckLink.set("keyerInterfaceAvailable", JsonValue(mDeckLinkOutputStatus.keyerInterfaceAvailable));
-	deckLink.set("externalKeyingRequested", JsonValue(mDeckLinkOutputStatus.externalKeyingRequested));
-	deckLink.set("externalKeyingActive", JsonValue(mDeckLinkOutputStatus.externalKeyingActive));
-	deckLink.set("statusMessage", JsonValue(mDeckLinkOutputStatus.statusMessage));
-	root.set("decklink", deckLink);
-
 	JsonValue videoIO = JsonValue::MakeObject();
-	videoIO.set("backend", JsonValue(mDeckLinkOutputStatus.backendName));
-	videoIO.set("modelName", JsonValue(mDeckLinkOutputStatus.modelName));
-	videoIO.set("supportsInternalKeying", JsonValue(mDeckLinkOutputStatus.supportsInternalKeying));
-	videoIO.set("supportsExternalKeying", JsonValue(mDeckLinkOutputStatus.supportsExternalKeying));
-	videoIO.set("keyerInterfaceAvailable", JsonValue(mDeckLinkOutputStatus.keyerInterfaceAvailable));
-	videoIO.set("externalKeyingRequested", JsonValue(mDeckLinkOutputStatus.externalKeyingRequested));
-	videoIO.set("externalKeyingActive", JsonValue(mDeckLinkOutputStatus.externalKeyingActive));
-	videoIO.set("statusMessage", JsonValue(mDeckLinkOutputStatus.statusMessage));
+	videoIO.set("backend", JsonValue(VideoIOBackendName(mVideoIOStatus.backendId)));
+	videoIO.set("deviceName", JsonValue(mVideoIOStatus.deviceName));
+	videoIO.set("hasInputDevice", JsonValue(mVideoIOStatus.hasInputDevice));
+	videoIO.set("hasInputSource", JsonValue(mVideoIOStatus.hasInputSource));
+	videoIO.set("inputModeName", JsonValue(mVideoIOStatus.inputDisplayModeName));
+	videoIO.set("outputModeName", JsonValue(mVideoIOStatus.outputDisplayModeName));
+	JsonValue capabilities = JsonValue::MakeObject();
+	capabilities.set("supportsInternalKeying", JsonValue(mVideoIOStatus.capabilities.supportsInternalKeying));
+	capabilities.set("supportsExternalKeying", JsonValue(mVideoIOStatus.capabilities.supportsExternalKeying));
+	capabilities.set("keyerInterfaceAvailable", JsonValue(mVideoIOStatus.capabilities.keyerInterfaceAvailable));
+	videoIO.set("capabilities", capabilities);
+	videoIO.set("externalKeyingRequested", JsonValue(mVideoIOStatus.externalKeyingRequested));
+	videoIO.set("externalKeyingActive", JsonValue(mVideoIOStatus.externalKeyingActive));
+	videoIO.set("statusMessage", JsonValue(mVideoIOStatus.statusMessage));
+	videoIO.set("formatStatusMessage", JsonValue(mVideoIOStatus.formatStatusMessage));
 	root.set("videoIO", videoIO);

 	JsonValue performance = JsonValue::MakeObject();
--- a/apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeHost.h
+++ b/apps/LoopThroughWithOpenGLCompositing/runtime/RuntimeHost.h
@@ -2,6 +2,7 @@

 #include "RuntimeJson.h"
 #include "ShaderTypes.h"
+#include "VideoIOTypes.h"

 #include <atomic>
 #include <chrono>
@@ -38,10 +39,7 @@ public:
 	void SetCompileStatus(bool succeeded, const std::string& message);
 	void SetSignalStatus(bool hasSignal, unsigned width, unsigned height, const std::string& modeName);
 	bool TrySetSignalStatus(bool hasSignal, unsigned width, unsigned height, const std::string& modeName);
-	void SetDeckLinkOutputStatus(const std::string& modelName, bool supportsInternalKeying, bool supportsExternalKeying,
-		bool keyerInterfaceAvailable, bool externalKeyingRequested, bool externalKeyingActive, const std::string& statusMessage);
-	void SetVideoIOStatus(const std::string& backendName, const std::string& modelName, bool supportsInternalKeying, bool supportsExternalKeying,
-		bool keyerInterfaceAvailable, bool externalKeyingRequested, bool externalKeyingActive, const std::string& statusMessage);
+	void SetVideoIOStatus(const VideoIOState& state);
 	void SetPerformanceStats(double frameBudgetMilliseconds, double renderMilliseconds);
 	bool TrySetPerformanceStats(double frameBudgetMilliseconds, double renderMilliseconds);
 	void SetFramePacingStats(double completionIntervalMilliseconds, double smoothedCompletionIntervalMilliseconds,
@@ -56,6 +54,7 @@ public:
 	bool TryGetLayerRenderStates(unsigned outputWidth, unsigned outputHeight, std::vector<RuntimeRenderState>& states) const;
 	void RefreshDynamicRenderStateFields(std::vector<RuntimeRenderState>& states) const;
 	std::string BuildStateJson() const;
+	uint64_t GetRenderStateVersion() const { return mRenderStateVersion.load(std::memory_order_relaxed); }

 	const std::filesystem::path& GetRepoRoot() const { return mRepoRoot; }
 	const std::filesystem::path& GetUiRoot() const { return mUiRoot; }
@@ -64,11 +63,8 @@ public:
 	unsigned short GetServerPort() const { return mServerPort; }
 	unsigned short GetOscPort() const { return mConfig.oscPort; }
 	unsigned GetMaxTemporalHistoryFrames() const { return mConfig.maxTemporalHistoryFrames; }
-	bool ExternalKeyingEnabled() const { return mConfig.enableExternalKeying; }
-	const std::string& GetInputVideoFormat() const { return mConfig.inputVideoFormat; }
-	const std::string& GetInputFrameRate() const { return mConfig.inputFrameRate; }
-	const std::string& GetOutputVideoFormat() const { return mConfig.outputVideoFormat; }
-	const std::string& GetOutputFrameRate() const { return mConfig.outputFrameRate; }
+	bool ExternalKeyingEnabled() const { return mConfig.videoIO.externalKeyingEnabled; }
+	VideoIOConfiguration GetVideoIOConfiguration() const { return mConfig.videoIO; }
 	void SetServerPort(unsigned short port);
 	bool AutoReloadEnabled() const { return mAutoReloadEnabled; }

@@ -80,23 +76,22 @@ private:
 		unsigned short oscPort = 9000;
 		bool autoReload = true;
 		unsigned maxTemporalHistoryFrames = 4;
-		bool enableExternalKeying = false;
-		std::string inputVideoFormat = "1080p";
-		std::string inputFrameRate = "59.94";
-		std::string outputVideoFormat = "1080p";
-		std::string outputFrameRate = "59.94";
+		VideoIOConfiguration videoIO;
 	};

-	struct DeckLinkOutputStatus
+	struct VideoIOStatusSnapshot
 	{
-		std::string backendName = "decklink";
-		std::string modelName;
-		bool supportsInternalKeying = false;
-		bool supportsExternalKeying = false;
-		bool keyerInterfaceAvailable = false;
+		VideoIOBackendId backendId = VideoIOBackendId::DeckLink;
+		std::string deviceName;
+		VideoIOCapabilities capabilities;
+		bool hasInputDevice = false;
+		bool hasInputSource = false;
+		std::string inputDisplayModeName = "1080p59.94";
+		std::string outputDisplayModeName = "1080p59.94";
 		bool externalKeyingRequested = false;
 		bool externalKeyingActive = false;
 		std::string statusMessage;
+		std::string formatStatusMessage;
 	};

 	struct LayerPersistentState
@@ -135,6 +130,7 @@ private:
 	const LayerPersistentState* FindLayerById(const std::string& layerId) const;
 	std::string GenerateLayerId();
 	void SetSignalStatusLocked(bool hasSignal, unsigned width, unsigned height, const std::string& modeName);
+	void MarkRenderStateDirtyLocked();
 	void SetPerformanceStatsLocked(double frameBudgetMilliseconds, double renderMilliseconds);
 	void SetFramePacingStatsLocked(double completionIntervalMilliseconds, double smoothedCompletionIntervalMilliseconds,
 		double maxCompletionIntervalMilliseconds, uint64_t lateFrameCount, uint64_t droppedFrameCount, uint64_t flushedFrameCount);
@@ -174,11 +170,12 @@ private:
 	uint64_t mLateFrameCount;
 	uint64_t mDroppedFrameCount;
 	uint64_t mFlushedFrameCount;
-	DeckLinkOutputStatus mDeckLinkOutputStatus;
+	VideoIOStatusSnapshot mVideoIOStatus;
 	unsigned short mServerPort;
 	bool mAutoReloadEnabled;
 	std::chrono::steady_clock::time_point mStartTime;
 	std::chrono::steady_clock::time_point mLastScanTime;
-	std::atomic<uint64_t> mFrameCounter;
+	std::atomic<uint64_t> mFrameCounter{ 0 };
+	std::atomic<uint64_t> mRenderStateVersion{ 0 };
 	uint64_t mNextLayerId;
 };
--- a/apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOBackendFactory.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOBackendFactory.cpp
@@ -0,0 +1,16 @@
+#include "VideoIOBackendFactory.h"
+
+#include "DeckLinkSession.h"
+#include "VideoIOTypes.h"
+
+std::unique_ptr<VideoIODevice> CreateVideoIODevice(VideoIOBackendId backendId, std::string& error)
+{
+	switch (backendId)
+	{
+	case VideoIOBackendId::DeckLink:
+		return std::make_unique<DeckLinkSession>();
+	}
+
+	error = "Unsupported video I/O backend.";
+	return nullptr;
+}
--- a/apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOBackendFactory.h
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOBackendFactory.h
@@ -0,0 +1,10 @@
+#pragma once
+
+#include "VideoIOConfig.h"
+
+#include <memory>
+#include <string>
+
+class VideoIODevice;
+
+std::unique_ptr<VideoIODevice> CreateVideoIODevice(VideoIOBackendId backendId, std::string& error);
--- a/apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOConfig.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOConfig.cpp
@@ -0,0 +1,35 @@
+#include "VideoIOConfig.h"
+
+#include <algorithm>
+#include <cctype>
+
+namespace
+{
+std::string NormalizeToken(std::string value)
+{
+	std::transform(value.begin(), value.end(), value.begin(),
+		[](unsigned char ch) { return static_cast<char>(std::tolower(ch)); });
+	return value;
+}
+}
+
+const char* VideoIOBackendName(VideoIOBackendId backendId)
+{
+	switch (backendId)
+	{
+	case VideoIOBackendId::DeckLink:
+		return "decklink";
+	}
+	return "unknown";
+}
+
+bool ParseVideoIOBackendId(const std::string& value, VideoIOBackendId& backendId)
+{
+	const std::string normalized = NormalizeToken(value);
+	if (normalized.empty() || normalized == "decklink")
+	{
+		backendId = VideoIOBackendId::DeckLink;
+		return true;
+	}
+	return false;
+}
--- a/apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOConfig.h
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOConfig.h
@@ -0,0 +1,44 @@
+#pragma once
+
+#include <string>
+
+enum class VideoIOBackendId
+{
+	DeckLink
+};
+
+const char* VideoIOBackendName(VideoIOBackendId backendId);
+bool ParseVideoIOBackendId(const std::string& value, VideoIOBackendId& backendId);
+
+struct FrameSize
+{
+	unsigned width = 0;
+	unsigned height = 0;
+
+	bool IsEmpty() const { return width == 0 || height == 0; }
+};
+
+inline bool operator==(const FrameSize& left, const FrameSize& right)
+{
+	return left.width == right.width && left.height == right.height;
+}
+
+inline bool operator!=(const FrameSize& left, const FrameSize& right)
+{
+	return !(left == right);
+}
+
+struct VideoIOModeConfiguration
+{
+	std::string videoFormat = "1080p";
+	std::string frameRate = "59.94";
+};
+
+struct VideoIOConfiguration
+{
+	VideoIOBackendId backendId = VideoIOBackendId::DeckLink;
+	VideoIOModeConfiguration inputMode;
+	VideoIOModeConfiguration outputMode;
+	bool externalKeyingEnabled = false;
+	bool preferTenBit = true;
+};
--- a/apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOTypes.h
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/VideoIOTypes.h
@@ -1,15 +1,17 @@
 #pragma once

-#include "DeckLinkDisplayMode.h"
+#include "VideoIOConfig.h"
 #include "VideoIOFormat.h"

 #include <cstdint>
 #include <functional>
 #include <string>

-enum class VideoIOBackend
+struct VideoIOCapabilities
 {
-	DeckLink
+	bool supportsInternalKeying = false;
+	bool supportsExternalKeying = false;
+	bool keyerInterfaceAvailable = false;
 };

 enum class VideoIOCompletionResult
@@ -21,15 +23,9 @@ enum class VideoIOCompletionResult
 	Unknown
 };

-struct VideoIOConfig
-{
-	VideoFormatSelection videoModes;
-	bool externalKeyingEnabled = false;
-	bool preferTenBit = true;
-};
-
 struct VideoIOState
 {
+	VideoIOBackendId backendId = VideoIOBackendId::DeckLink;
 	FrameSize inputFrameSize;
 	FrameSize outputFrameSize;
 	VideoIOPixelFormat inputPixelFormat = VideoIOPixelFormat::Uyvy8;
@@ -40,14 +36,13 @@ struct VideoIOState
 	unsigned outputPackTextureWidth = 0;
 	std::string inputDisplayModeName = "1080p59.94";
 	std::string outputDisplayModeName = "1080p59.94";
-	std::string outputModelName;
+	std::string deviceName;
 	std::string statusMessage;
 	std::string formatStatusMessage;
 	bool hasInputDevice = false;
 	bool hasInputSource = false;
-	bool supportsInternalKeying = false;
-	bool supportsExternalKeying = false;
-	bool keyerInterfaceAvailable = false;
+	VideoIOCapabilities capabilities;
+	bool externalKeyingRequested = false;
 	bool externalKeyingActive = false;
 	double frameBudgetMilliseconds = 0.0;
 };
@@ -93,11 +88,12 @@ public:
 	using OutputFrameCallback = std::function<void(const VideoIOCompletion&)>;

 	virtual ~VideoIODevice() = default;
+	virtual VideoIOBackendId BackendId() const = 0;
 	virtual void ReleaseResources() = 0;
-	virtual bool DiscoverDevicesAndModes(const VideoFormatSelection& videoModes, std::string& error) = 0;
-	virtual bool SelectPreferredFormats(const VideoFormatSelection& videoModes, bool outputAlphaRequired, std::string& error) = 0;
-	virtual bool ConfigureInput(InputFrameCallback callback, const VideoFormat& inputVideoMode, std::string& error) = 0;
-	virtual bool ConfigureOutput(OutputFrameCallback callback, const VideoFormat& outputVideoMode, bool externalKeyingEnabled, std::string& error) = 0;
+	virtual bool DiscoverDevicesAndModes(const VideoIOConfiguration& config, std::string& error) = 0;
+	virtual bool SelectPreferredFormats(const VideoIOConfiguration& config, std::string& error) = 0;
+	virtual bool ConfigureInput(InputFrameCallback callback, std::string& error) = 0;
+	virtual bool ConfigureOutput(OutputFrameCallback callback, std::string& error) = 0;
 	virtual bool Start() = 0;
 	virtual bool Stop() = 0;
 	virtual const VideoIOState& State() const = 0;
@@ -126,10 +122,11 @@ public:
 	unsigned OutputPackTextureWidth() const { return State().outputPackTextureWidth; }
 	const std::string& FormatStatusMessage() const { return State().formatStatusMessage; }
 	const std::string& InputDisplayModeName() const { return State().inputDisplayModeName; }
-	const std::string& OutputModelName() const { return State().outputModelName; }
-	bool SupportsInternalKeying() const { return State().supportsInternalKeying; }
-	bool SupportsExternalKeying() const { return State().supportsExternalKeying; }
-	bool KeyerInterfaceAvailable() const { return State().keyerInterfaceAvailable; }
+	const std::string& DeviceName() const { return State().deviceName; }
+	bool SupportsInternalKeying() const { return State().capabilities.supportsInternalKeying; }
+	bool SupportsExternalKeying() const { return State().capabilities.supportsExternalKeying; }
+	bool KeyerInterfaceAvailable() const { return State().capabilities.keyerInterfaceAvailable; }
+	bool ExternalKeyingRequested() const { return State().externalKeyingRequested; }
 	bool ExternalKeyingActive() const { return State().externalKeyingActive; }
 	const std::string& StatusMessage() const { return State().statusMessage; }
 	double FrameBudgetMilliseconds() const { return State().frameBudgetMilliseconds; }
--- a/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkDisplayMode.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkDisplayMode.cpp
@@ -13,10 +13,10 @@ std::string NormalizeModeToken(const std::string& value)
 	return normalized;
 }

-bool ResolveConfiguredDisplayMode(const std::string& videoFormat, const std::string& frameRate, BMDDisplayMode& displayMode, std::string& displayModeName)
+bool ResolveConfiguredDeckLinkDisplayMode(const VideoIOModeConfiguration& mode, BMDDisplayMode& displayMode, std::string& displayModeName)
 {
-	VideoFormat videoMode;
-	if (!ResolveConfiguredVideoFormat(videoFormat, frameRate, videoMode))
+	DeckLinkVideoMode videoMode;
+	if (!ResolveConfiguredDeckLinkVideoMode(mode, videoMode))
 		return false;

 	displayMode = videoMode.displayMode;
@@ -24,10 +24,10 @@ bool ResolveConfiguredDisplayMode(const std::string& videoFormat, const std::str
 	return true;
 }

-bool ResolveConfiguredVideoFormat(const std::string& videoFormat, const std::string& frameRate, VideoFormat& videoMode)
+bool ResolveConfiguredDeckLinkVideoMode(const VideoIOModeConfiguration& mode, DeckLinkVideoMode& videoMode)
 {
-	const std::string formatToken = NormalizeModeToken(videoFormat);
-	const std::string frameToken = NormalizeModeToken(frameRate);
+	const std::string formatToken = NormalizeModeToken(mode.videoFormat);
+	const std::string frameToken = NormalizeModeToken(mode.frameRate);
 	const std::string combinedToken = formatToken + frameToken;

 	struct ModeOption
@@ -98,25 +98,22 @@ bool ResolveConfiguredVideoFormat(const std::string& videoFormat, const std::str
 	return false;
 }

-bool ResolveConfiguredVideoFormats(
-	const std::string& inputVideoFormat,
-	const std::string& inputFrameRate,
-	const std::string& outputVideoFormat,
-	const std::string& outputFrameRate,
-	VideoFormatSelection& videoModes,
+bool ResolveConfiguredDeckLinkVideoModes(
+	const VideoIOConfiguration& config,
+	DeckLinkVideoModeSelection& videoModes,
 	std::string& error)
 {
-	if (!ResolveConfiguredVideoFormat(inputVideoFormat, inputFrameRate, videoModes.input))
+	if (!ResolveConfiguredDeckLinkVideoMode(config.inputMode, videoModes.input))
 	{
-		error = "Unsupported DeckLink inputVideoFormat/inputFrameRate in config/runtime-host.json: " +
-			inputVideoFormat + " / " + inputFrameRate;
+		error = "Unsupported DeckLink input mode in config/runtime-host.json: " +
+			config.inputMode.videoFormat + " / " + config.inputMode.frameRate;
 		return false;
 	}

-	if (!ResolveConfiguredVideoFormat(outputVideoFormat, outputFrameRate, videoModes.output))
+	if (!ResolveConfiguredDeckLinkVideoMode(config.outputMode, videoModes.output))
 	{
-		error = "Unsupported DeckLink outputVideoFormat/outputFrameRate in config/runtime-host.json: " +
-			outputVideoFormat + " / " + outputFrameRate;
+		error = "Unsupported DeckLink output mode in config/runtime-host.json: " +
+			config.outputMode.videoFormat + " / " + config.outputMode.frameRate;
 		return false;
 	}

--- a/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkDisplayMode.h
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkDisplayMode.h
@@ -1,47 +1,27 @@
 #pragma once

 #include "DeckLinkAPI_h.h"
+#include "VideoIOConfig.h"

 #include <string>

-struct FrameSize
-{
-	unsigned width = 0;
-	unsigned height = 0;
-
-	bool IsEmpty() const { return width == 0 || height == 0; }
-};
-
-inline bool operator==(const FrameSize& left, const FrameSize& right)
-{
-	return left.width == right.width && left.height == right.height;
-}
-
-inline bool operator!=(const FrameSize& left, const FrameSize& right)
-{
-	return !(left == right);
-}
-
-struct VideoFormat
+struct DeckLinkVideoMode
 {
 	BMDDisplayMode displayMode = bmdModeHD1080p5994;
 	std::string displayName = "1080p59.94";
 };

-struct VideoFormatSelection
+struct DeckLinkVideoModeSelection
 {
-	VideoFormat input;
-	VideoFormat output;
+	DeckLinkVideoMode input;
+	DeckLinkVideoMode output;
 };

 std::string NormalizeModeToken(const std::string& value);
-bool ResolveConfiguredDisplayMode(const std::string& videoFormat, const std::string& frameRate, BMDDisplayMode& displayMode, std::string& displayModeName);
-bool ResolveConfiguredVideoFormat(const std::string& videoFormat, const std::string& frameRate, VideoFormat& videoMode);
-bool ResolveConfiguredVideoFormats(
-	const std::string& inputVideoFormat,
-	const std::string& inputFrameRate,
-	const std::string& outputVideoFormat,
-	const std::string& outputFrameRate,
-	VideoFormatSelection& videoModes,
+bool ResolveConfiguredDeckLinkDisplayMode(const VideoIOModeConfiguration& mode, BMDDisplayMode& displayMode, std::string& displayModeName);
+bool ResolveConfiguredDeckLinkVideoMode(const VideoIOModeConfiguration& mode, DeckLinkVideoMode& videoMode);
+bool ResolveConfiguredDeckLinkVideoModes(
+	const VideoIOConfiguration& config,
+	DeckLinkVideoModeSelection& videoModes,
 	std::string& error);
 bool FindDeckLinkDisplayMode(IDeckLinkDisplayModeIterator* iterator, BMDDisplayMode targetMode, IDeckLinkDisplayMode** foundMode);
--- a/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.cpp
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.cpp
@@ -92,14 +92,19 @@ void DeckLinkSession::ReleaseResources()
 	output.Release();
 }

-bool DeckLinkSession::DiscoverDevicesAndModes(const VideoFormatSelection& videoModes, std::string& error)
+bool DeckLinkSession::DiscoverDevicesAndModes(const VideoIOConfiguration& config, std::string& error)
 {
 	CComPtr<IDeckLinkIterator> deckLinkIterator;
 	CComPtr<IDeckLinkDisplayMode> inputMode;
 	CComPtr<IDeckLinkDisplayMode> outputMode;

-	mState.inputDisplayModeName = videoModes.input.displayName;
-	mState.outputDisplayModeName = videoModes.output.displayName;
+	mState.backendId = BackendId();
+	mState.externalKeyingRequested = config.externalKeyingEnabled;
+	if (!ResolveConfiguredDeckLinkVideoModes(config, mConfiguredModes, error))
+		return false;
+
+	mState.inputDisplayModeName = mConfiguredModes.input.displayName;
+	mState.outputDisplayModeName = mConfiguredModes.output.displayName;

 	HRESULT result = CoCreateInstance(CLSID_CDeckLinkIterator, nullptr, CLSCTX_ALL, IID_IDeckLinkIterator, reinterpret_cast<void**>(&deckLinkIterator));
 	if (FAILED(result))
@@ -151,9 +156,9 @@ bool DeckLinkSession::DiscoverDevicesAndModes(const VideoFormatSelection& videoM
 				output.Release();
 			else
 			{
-				mState.outputModelName = modelName;
-				mState.supportsInternalKeying = deviceSupportsInternalKeying;
-				mState.supportsExternalKeying = deviceSupportsExternalKeying;
+				mState.deviceName = modelName;
+				mState.capabilities.supportsInternalKeying = deviceSupportsInternalKeying;
+				mState.capabilities.supportsExternalKeying = deviceSupportsExternalKeying;
 			}
 		}

@@ -178,9 +183,9 @@ bool DeckLinkSession::DiscoverDevicesAndModes(const VideoFormatSelection& videoM
 		return false;
 	}

-	if (input && !FindDeckLinkDisplayMode(inputDisplayModeIterator, videoModes.input.displayMode, &inputMode))
+	if (input && !FindDeckLinkDisplayMode(inputDisplayModeIterator, mConfiguredModes.input.displayMode, &inputMode))
 	{
-		error = "Cannot get specified input BMDDisplayMode for configured mode: " + videoModes.input.displayName;
+		error = "Cannot get specified input BMDDisplayMode for configured mode: " + mConfiguredModes.input.displayName;
 		ReleaseResources();
 		return false;
 	}
@@ -194,9 +199,9 @@ bool DeckLinkSession::DiscoverDevicesAndModes(const VideoFormatSelection& videoM
 		return false;
 	}

-	if (!FindDeckLinkDisplayMode(outputDisplayModeIterator, videoModes.output.displayMode, &outputMode))
+	if (!FindDeckLinkDisplayMode(outputDisplayModeIterator, mConfiguredModes.output.displayMode, &outputMode))
 	{
-		error = "Cannot get specified output BMDDisplayMode for configured mode: " + videoModes.output.displayName;
+		error = "Cannot get specified output BMDDisplayMode for configured mode: " + mConfiguredModes.output.displayName;
 		ReleaseResources();
 		return false;
 	}
@@ -223,7 +228,7 @@ bool DeckLinkSession::DiscoverDevicesAndModes(const VideoFormatSelection& videoM
 	return true;
 }

-bool DeckLinkSession::SelectPreferredFormats(const VideoFormatSelection& videoModes, bool outputAlphaRequired, std::string& error)
+bool DeckLinkSession::SelectPreferredFormats(const VideoIOConfiguration& config, std::string& error)
 {
 	if (!output)
 	{
@@ -233,19 +238,19 @@ bool DeckLinkSession::SelectPreferredFormats(const VideoFormatSelection& videoMo

 	mState.formatStatusMessage.clear();

-	const bool inputTenBitSupported = input != nullptr && InputSupportsFormat(input, videoModes.input.displayMode, bmdFormat10BitYUV);
+	const bool inputTenBitSupported = input != nullptr && InputSupportsFormat(input, mConfiguredModes.input.displayMode, bmdFormat10BitYUV);
 	mState.inputPixelFormat = input != nullptr ? ChoosePreferredVideoIOFormat(inputTenBitSupported) : VideoIOPixelFormat::Uyvy8;
 	if (input != nullptr && !inputTenBitSupported)
 		mState.formatStatusMessage += "DeckLink input does not report 10-bit YUV support for the configured mode; using 8-bit capture. ";

-	const bool outputTenBitSupported = OutputSupportsFormat(output, videoModes.output.displayMode, bmdFormat10BitYUV);
-	const bool outputTenBitYuvaSupported = OutputSupportsFormat(output, videoModes.output.displayMode, bmdFormat10BitYUVA);
-	mState.outputPixelFormat = outputAlphaRequired
+	const bool outputTenBitSupported = OutputSupportsFormat(output, mConfiguredModes.output.displayMode, bmdFormat10BitYUV);
+	const bool outputTenBitYuvaSupported = OutputSupportsFormat(output, mConfiguredModes.output.displayMode, bmdFormat10BitYUVA);
+	mState.outputPixelFormat = config.externalKeyingEnabled
 		? (outputTenBitYuvaSupported ? VideoIOPixelFormat::Yuva10 : VideoIOPixelFormat::Bgra8)
 		: (outputTenBitSupported ? VideoIOPixelFormat::V210 : VideoIOPixelFormat::Bgra8);
-	if (outputAlphaRequired && outputTenBitYuvaSupported)
+	if (config.externalKeyingEnabled && outputTenBitYuvaSupported)
 		mState.formatStatusMessage += "External keying requires alpha; using 10-bit YUVA output. ";
-	else if (outputAlphaRequired)
+	else if (config.externalKeyingEnabled)
 		mState.formatStatusMessage += "External keying requires alpha, but DeckLink output does not report 10-bit YUVA support for the configured mode; using 8-bit BGRA output. ";
 	else if (!outputTenBitSupported)
 		mState.formatStatusMessage += "DeckLink output does not report 10-bit YUV support for the configured mode; using 8-bit BGRA output. ";
@@ -286,7 +291,7 @@ bool DeckLinkSession::SelectPreferredFormats(const VideoFormatSelection& videoMo
 	return true;
 }

-bool DeckLinkSession::ConfigureInput(InputFrameCallback callback, const VideoFormat& inputVideoMode, std::string& error)
+bool DeckLinkSession::ConfigureInput(InputFrameCallback callback, std::string& error)
 {
 	mInputFrameCallback = std::move(callback);

@@ -298,7 +303,7 @@ bool DeckLinkSession::ConfigureInput(InputFrameCallback callback, const VideoFor
 	}

 	const BMDPixelFormat deckLinkInputPixelFormat = DeckLinkPixelFormatForVideoIO(mState.inputPixelFormat);
-	if (input->EnableVideoInput(inputVideoMode.displayMode, deckLinkInputPixelFormat, bmdVideoInputFlagDefault) != S_OK)
+	if (input->EnableVideoInput(mConfiguredModes.input.displayMode, deckLinkInputPixelFormat, bmdVideoInputFlagDefault) != S_OK)
 	{
 		if (mState.inputPixelFormat == VideoIOPixelFormat::V210)
 		{
@@ -306,7 +311,7 @@ bool DeckLinkSession::ConfigureInput(InputFrameCallback callback, const VideoFor
 			mState.inputPixelFormat = VideoIOPixelFormat::Uyvy8;
 			mState.inputFrameRowBytes = mState.inputFrameSize.width * 2u;
 			mState.captureTextureWidth = mState.inputFrameSize.width / 2u;
-			if (input->EnableVideoInput(inputVideoMode.displayMode, bmdFormat8BitYUV, bmdVideoInputFlagDefault) == S_OK)
+			if (input->EnableVideoInput(mConfiguredModes.input.displayMode, bmdFormat8BitYUV, bmdVideoInputFlagDefault) == S_OK)
 			{
 				std::ostringstream status;
 				status << "DeckLink formats: capture " << VideoIOPixelFormatName(mState.inputPixelFormat)
@@ -341,26 +346,26 @@ input_enabled:
 	return true;
 }

-bool DeckLinkSession::ConfigureOutput(OutputFrameCallback callback, const VideoFormat& outputVideoMode, bool externalKeyingEnabled, std::string& error)
+bool DeckLinkSession::ConfigureOutput(OutputFrameCallback callback, std::string& error)
 {
 	mOutputFrameCallback = std::move(callback);

-	if (output->EnableVideoOutput(outputVideoMode.displayMode, bmdVideoOutputFlagDefault) != S_OK)
+	if (output->EnableVideoOutput(mConfiguredModes.output.displayMode, bmdVideoOutputFlagDefault) != S_OK)
 	{
 		error = "DeckLink output setup failed while enabling video output.";
 		return false;
 	}

 	if (output->QueryInterface(IID_IDeckLinkKeyer, (void**)&keyer) == S_OK && keyer != NULL)
-		mState.keyerInterfaceAvailable = true;
+		mState.capabilities.keyerInterfaceAvailable = true;

-	if (externalKeyingEnabled)
+	if (mState.externalKeyingRequested)
 	{
-		if (!mState.supportsExternalKeying)
+		if (!mState.capabilities.supportsExternalKeying)
 		{
 			mState.statusMessage = "External keying was requested, but the selected DeckLink output does not report external keying support.";
 		}
-		else if (!mState.keyerInterfaceAvailable)
+		else if (!mState.capabilities.keyerInterfaceAvailable)
 		{
 			mState.statusMessage = "External keying was requested, but the selected DeckLink output does not expose the IDeckLinkKeyer interface.";
 		}
@@ -374,7 +379,7 @@ bool DeckLinkSession::ConfigureOutput(OutputFrameCallback callback, const VideoF
 			mState.statusMessage = "External keying is active on the selected DeckLink output.";
 		}
 	}
-	else if (mState.supportsExternalKeying)
+	else if (mState.capabilities.supportsExternalKeying)
 	{
 		mState.statusMessage = "Selected DeckLink output supports external keying. Set enableExternalKeying to true in runtime-host.json to request it.";
 	}
--- a/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.h
+++ b/apps/LoopThroughWithOpenGLCompositing/videoio/decklink/DeckLinkSession.h
@@ -20,41 +20,14 @@ public:
 	DeckLinkSession() = default;
 	~DeckLinkSession();

+	VideoIOBackendId BackendId() const override { return VideoIOBackendId::DeckLink; }
 	void ReleaseResources() override;
-	bool DiscoverDevicesAndModes(const VideoFormatSelection& videoModes, std::string& error) override;
-	bool SelectPreferredFormats(const VideoFormatSelection& videoModes, bool outputAlphaRequired, std::string& error) override;
-	bool ConfigureInput(InputFrameCallback callback, const VideoFormat& inputVideoMode, std::string& error) override;
-	bool ConfigureOutput(OutputFrameCallback callback, const VideoFormat& outputVideoMode, bool externalKeyingEnabled, std::string& error) override;
+	bool DiscoverDevicesAndModes(const VideoIOConfiguration& config, std::string& error) override;
+	bool SelectPreferredFormats(const VideoIOConfiguration& config, std::string& error) override;
+	bool ConfigureInput(InputFrameCallback callback, std::string& error) override;
+	bool ConfigureOutput(OutputFrameCallback callback, std::string& error) override;
 	bool Start() override;
 	bool Stop() override;
-
-	bool HasInputDevice() const { return mState.hasInputDevice; }
-	bool HasInputSource() const { return mState.hasInputSource; }
-	void SetInputSourceMissing(bool missing) { mState.hasInputSource = !missing; }
-	bool InputOutputDimensionsDiffer() const { return mState.inputFrameSize != mState.outputFrameSize; }
-	const FrameSize& InputFrameSize() const { return mState.inputFrameSize; }
-	const FrameSize& OutputFrameSize() const { return mState.outputFrameSize; }
-	unsigned InputFrameWidth() const { return mState.inputFrameSize.width; }
-	unsigned InputFrameHeight() const { return mState.inputFrameSize.height; }
-	unsigned OutputFrameWidth() const { return mState.outputFrameSize.width; }
-	unsigned OutputFrameHeight() const { return mState.outputFrameSize.height; }
-	VideoIOPixelFormat InputPixelFormat() const { return mState.inputPixelFormat; }
-	VideoIOPixelFormat OutputPixelFormat() const { return mState.outputPixelFormat; }
-	bool InputIsTenBit() const { return VideoIOPixelFormatIsTenBit(mState.inputPixelFormat); }
-	bool OutputIsTenBit() const { return VideoIOPixelFormatIsTenBit(mState.outputPixelFormat); }
-	unsigned InputFrameRowBytes() const { return mState.inputFrameRowBytes; }
-	unsigned OutputFrameRowBytes() const { return mState.outputFrameRowBytes; }
-	unsigned CaptureTextureWidth() const { return mState.captureTextureWidth; }
-	unsigned OutputPackTextureWidth() const { return mState.outputPackTextureWidth; }
-	const std::string& FormatStatusMessage() const { return mState.formatStatusMessage; }
-	const std::string& InputDisplayModeName() const { return mState.inputDisplayModeName; }
-	const std::string& OutputModelName() const { return mState.outputModelName; }
-	bool SupportsInternalKeying() const { return mState.supportsInternalKeying; }
-	bool SupportsExternalKeying() const { return mState.supportsExternalKeying; }
-	bool KeyerInterfaceAvailable() const { return mState.keyerInterfaceAvailable; }
-	bool ExternalKeyingActive() const { return mState.externalKeyingActive; }
-	const std::string& StatusMessage() const { return mState.statusMessage; }
-	void SetStatusMessage(const std::string& message) { mState.statusMessage = message; }
 	const VideoIOState& State() const override { return mState; }
 	VideoIOState& MutableState() override { return mState; }
 	double FrameBudgetMilliseconds() const;
@@ -76,4 +49,5 @@ private:
 	VideoPlayoutScheduler					mScheduler;
 	InputFrameCallback						mInputFrameCallback;
 	OutputFrameCallback						mOutputFrameCallback;
+	DeckLinkVideoModeSelection				mConfiguredModes;
 };
--- a/config/runtime-host.json
+++ b/config/runtime-host.json
@@ -2,6 +2,7 @@
  "shaderLibrary": "shaders",
  "serverPort": 8080,
  "oscPort": 9000,
+  "videoBackend": "decklink",
  "inputVideoFormat": "1080p",
  "inputFrameRate": "59.94",
  "outputVideoFormat": "1080p",
--- a/shaders/balatro-swirl/shader.slang
+++ b/shaders/balatro-swirl/shader.slang
@@ -6,6 +6,8 @@ float4 balatroSwirl(float2 screenSize, float2 screenCoords, float time, float se
 	float2 uv = (screenCoords - 0.5 * screenSize) / safeScreenLength - offset - seedOffset;
 	float uvLength = length(uv);

+	// First warp: convert to polar space and twist the angle more near the
+	// center, creating the large spiral motion.
 	float speed = spinRotation * spinEase * 0.2;
 	if (isRotate)
 		speed = time * speed;
@@ -19,6 +21,8 @@ float4 balatroSwirl(float2 screenSize, float2 screenCoords, float time, float se
 	speed = (time + seed * 17.0) * spinSpeed;
 	float2 uv2 = float2(uv.x + uv.y, uv.x + uv.y);

+	// Second warp: a short iterative feedback loop turns the spiral into
+	// painterly bands while preserving a fixed compile-time loop bound.
 	for (int i = 0; i < 5; ++i)
 	{
 		uv2 += float2(sin(max(uv.x, uv.y)), sin(max(uv.x, uv.y))) + uv;
@@ -32,6 +36,8 @@ float4 balatroSwirl(float2 screenSize, float2 screenCoords, float time, float se
 	float c1p = max(0.0, 1.0 - contrastMod * abs(1.0 - paintRes));
 	float c2p = max(0.0, 1.0 - contrastMod * abs(paintRes));
 	float c3p = 1.0 - min(1.0, c1p + c2p);
+	// Three soft band weights drive the palette; lighting rides on the brightest
+	// bands so the swirl keeps dimensional highlights.
 	float light = (lighting - 0.2) * max(c1p * 5.0 - 4.0, 0.0) + lighting * max(c2p * 5.0 - 4.0, 0.0);

 	float safeContrast = max(contrast, 0.001);
--- a/shaders/crt-bulge/shader.json
+++ b/shaders/crt-bulge/shader.json
@@ -0,0 +1,102 @@
+{
+  "id": "crt-bulge",
+  "name": "CRT Bulge",
+  "description": "Warps the image like convex CRT glass, with optional rounded screen edges and vignette darkening.",
+  "category": "Distortion",
+  "entryPoint": "shadeVideo",
+  "parameters": [
+    {
+      "id": "bulgeAmount",
+      "label": "Bulge",
+      "type": "float",
+      "default": -0.04,
+      "min": -0.5,
+      "max": 0.8,
+      "step": 0.01,
+      "description": "Positive values swell the center outward; negative values pinch it inward."
+    },
+    {
+      "id": "zoom",
+      "label": "Zoom",
+      "type": "float",
+      "default": 1.04,
+      "min": 0.5,
+      "max": 2,
+      "step": 0.01,
+      "description": "Scales the source before distortion, useful for hiding warped edges."
+    },
+    {
+      "id": "edgeRoundness",
+      "label": "Edge Roundness",
+      "type": "float",
+      "default": 0.08,
+      "min": 0,
+      "max": 0.35,
+      "step": 0.01,
+      "description": "Rounds the visible screen corners like older CRT glass."
+    },
+    {
+      "id": "edgeFeather",
+      "label": "Edge Feather",
+      "type": "float",
+      "default": 2,
+      "min": 0,
+      "max": 24,
+      "step": 0.1,
+      "description": "Softens the rounded screen edge in pixels."
+    },
+    {
+      "id": "sourceEdgeFeather",
+      "label": "Source Edge Feather",
+      "type": "float",
+      "default": 1.5,
+      "min": 0,
+      "max": 16,
+      "step": 0.1,
+      "description": "Antialiases warped source edges when the distortion reveals outside-frame pixels."
+    },
+    {
+      "id": "vignetteAmount",
+      "label": "Vignette",
+      "type": "float",
+      "default": 0.18,
+      "min": 0,
+      "max": 1,
+      "step": 0.01,
+      "description": "Darkens the glass toward the screen edges."
+    },
+    {
+      "id": "edgeMode",
+      "label": "Edge Mode",
+      "type": "enum",
+      "default": "black",
+      "options": [
+        {
+          "value": "black",
+          "label": "Black"
+        },
+        {
+          "value": "clamp",
+          "label": "Clamp"
+        },
+        {
+          "value": "mirror",
+          "label": "Mirror"
+        }
+      ],
+      "description": "Chooses how warped samples outside the source frame are filled."
+    },
+    {
+      "id": "outsideColor",
+      "label": "Outside Color",
+      "type": "color",
+      "default": [
+        0,
+        0,
+        0,
+        1
+      ],
+      "description": "Color used outside the curved screen or source frame."
+    }
+  ]
+}
--- a/shaders/crt-bulge/shader.slang
+++ b/shaders/crt-bulge/shader.slang
@@ -0,0 +1,71 @@
+float mirroredCoordinate(float coordinate)
+{
+	float wrapped = frac(coordinate * 0.5) * 2.0;
+	return wrapped <= 1.0 ? wrapped : 2.0 - wrapped;
+}
+
+float roundedBoxMask(float2 point, float2 halfSize, float radius, float feather)
+{
+	float2 distanceToEdge = abs(point) - (halfSize - radius);
+	float outsideDistance = length(max(distanceToEdge, float2(0.0, 0.0))) - radius;
+	float insideDistance = min(max(distanceToEdge.x, distanceToEdge.y), 0.0);
+	float signedDistance = outsideDistance + insideDistance;
+	return 1.0 - smoothstep(0.0, max(feather, 0.00001), signedDistance);
+}
+
+float sourceBoundsMask(float2 uv, float2 resolution)
+{
+	float2 pixel = 1.0 / max(resolution, float2(1.0, 1.0));
+	float2 feather = pixel * max(sourceEdgeFeather, 0.0);
+	float left = smoothstep(0.0, max(feather.x, 0.00001), uv.x);
+	float right = 1.0 - smoothstep(1.0 - max(feather.x, 0.00001), 1.0, uv.x);
+	float top = smoothstep(0.0, max(feather.y, 0.00001), uv.y);
+	float bottom = 1.0 - smoothstep(1.0 - max(feather.y, 0.00001), 1.0, uv.y);
+	return saturate(left * right * top * bottom);
+}
+
+float2 applyBulge(float2 uv, float2 resolution)
+{
+	float2 centered = uv * 2.0 - 1.0;
+	float aspect = resolution.x / max(resolution.y, 1.0);
+	float2 aspectCentered = float2(centered.x * aspect, centered.y);
+	float radiusSq = dot(aspectCentered, aspectCentered);
+	float amount = clamp(bulgeAmount, -0.95, 0.95);
+	float scale = 1.0 / max(1.0 + amount * radiusSq, 0.05);
+	return centered * scale / max(zoom, 0.001) * 0.5 + 0.5;
+}
+
+float4 sampleWarped(float2 uv, float2 resolution, out bool insideSource)
+{
+	insideSource = uv.x >= 0.0 && uv.x <= 1.0 && uv.y >= 0.0 && uv.y <= 1.0;
+
+	if (edgeMode == 1)
+		return sampleVideo(clamp(uv, 0.0, 1.0));
+	if (edgeMode == 2)
+		return sampleVideo(float2(mirroredCoordinate(uv.x), mirroredCoordinate(uv.y)));
+
+	float edgeMask = sourceBoundsMask(uv, resolution);
+	float4 color = sampleVideo(clamp(uv, 0.0, 1.0));
+	return lerp(outsideColor, color, edgeMask);
+}
+
+float4 shadeVideo(ShaderContext context)
+{
+	float2 resolution = max(context.outputResolution, float2(1.0, 1.0));
+	float2 sourceUv = applyBulge(context.uv, resolution);
+
+	bool insideSource = false;
+	float4 color = sampleWarped(sourceUv, resolution, insideSource);
+
+	float2 centered = context.uv * 2.0 - 1.0;
+	float feather = max(edgeFeather, 0.0) / min(resolution.x, resolution.y);
+	float screenMask = roundedBoxMask(centered, float2(1.0, 1.0), saturate(edgeRoundness), feather);
+	color = lerp(outsideColor, color, screenMask);
+
+	float2 aspectCentered = float2(centered.x * resolution.x / max(resolution.y, 1.0), centered.y);
+	float edgeDistance = saturate(length(aspectCentered) * 0.72);
+	float vignette = lerp(1.0, 1.0 - saturate(vignetteAmount), smoothstep(0.35, 1.05, edgeDistance));
+	color.rgb *= vignette;
+
+	return saturate(color);
+}
--- a/shaders/fisheye-equirectangular-mirror/shader.slang
+++ b/shaders/fisheye-equirectangular-mirror/shader.slang
@@ -31,6 +31,8 @@ float normalizedFisheyeRadius(float theta, float halfFov)
 {
 	float safeHalfFov = max(halfFov, 0.0001);

+	// Match common fisheye projection families while keeping the selected FOV
+	// normalized to the same source-image radius.
 	if (fisheyeModel == 1)
 	{
 		return sin(theta * 0.5) / max(sin(safeHalfFov * 0.5), 0.0001);
@@ -49,6 +51,7 @@ float normalizedFisheyeRadius(float theta, float halfFov)

 float3 equirectangularRay(float2 uv)
 {
+	// Convert equirectangular UVs into longitude/latitude on the unit sphere.
 	float longitude = (uv.x - 0.5) * TWO_PI;
 	float latitude = (0.5 - uv.y) * PI;
 	float latitudeCos = cos(latitude);
@@ -82,6 +85,8 @@ float4 sampleEdgeFilledVideo(float2 sourceUv, ShaderContext context)
 	float inwardLength = max(length(inward), 0.000001);
 	inward /= inwardLength;

+	// Outside the fisheye image, sample back inward from the nearest edge so the
+	// fill looks like stretched lens content instead of a hard color plate.
 	float blurDistance = max(edgeBlur, 0.0);
 	float4 color = sampleVideo(clampedUv) * 0.32;
 	color += sampleVideo(saturate(clampedUv + inward * blurDistance * 0.35)) * 0.26;
@@ -114,6 +119,7 @@ float4 shadeVideo(ShaderContext context)
 	float phi = atan2(ray.y, ray.x);
 	float fisheyeRadius = normalizedFisheyeRadius(theta, halfFov);

+	// Project the mirrored sphere ray back into the circular fisheye source.
 	float2 sourceUv = float2(
 		center.x + cos(phi) * fisheyeRadius * radius.x,
 		center.y - sin(phi) * fisheyeRadius * radius.y
--- a/shaders/fisheye-reproject/shader.slang
+++ b/shaders/fisheye-reproject/shader.slang
@@ -43,6 +43,8 @@ float normalizedFisheyeRadius(float theta, float halfFov)
 {
 	float safeHalfFov = max(halfFov, 0.0001);

+	// Different fisheye lenses map angle to image radius differently. Normalize
+	// each model by the selected half-FOV so the outer lens edge stays at 1.0.
 	if (fisheyeModel == 1)
 	{
 		return sin(theta * 0.5) / max(sin(safeHalfFov * 0.5), 0.0001);
@@ -67,6 +69,8 @@ float4 shadeVideo(ShaderContext context)
 	float virtualFov = radiansFromDegrees(clamp(virtualFovDegrees, 1.0, 175.0));
 	float tanHalfFov = tan(virtualFov * 0.5);

+	// Build a virtual output-camera ray, then rotate it into the fisheye lens
+	// coordinate system before asking where that ray lands on the source image.
 	float3 ray = outputProjection == 1
 		? buildCylindricalRay(screen, outputAspect, tanHalfFov)
 		: buildRectilinearRay(screen, outputAspect, tanHalfFov);
@@ -86,6 +90,7 @@ float4 shadeVideo(ShaderContext context)
 	float phi = atan2(ray.y, ray.x);
 	float fisheyeRadius = normalizedFisheyeRadius(theta, halfFov);

+	// Polar lens coordinates become UVs inside the circular fisheye image.
 	float2 sourceUv = float2(
 		center.x + cos(phi) * fisheyeRadius * radius.x,
 		center.y - sin(phi) * fisheyeRadius * radius.y
--- a/shaders/greenscreen-key/shader.slang
+++ b/shaders/greenscreen-key/shader.slang
@@ -23,6 +23,8 @@ float3 matteSampleColor(float2 uv, ShaderContext context)
 	if (blur <= 0.0001)
 		return center;

+	// Pre-blur only the color used for screen comparison; the final image keeps
+	// its original detail and alpha is refined in a later pass.
 	float2 radius = pixel * blur;
 	float3 color = center * 0.36;
 	color += saturate(sampleVideo(saturate(uv + float2(radius.x, 0.0))).rgb) * 0.16;
@@ -37,6 +39,8 @@ float keyDistanceAt(float2 uv, ShaderContext context)
 	float3 color = matteSampleColor(uv, context);
 	float3 keyColor = saturate(screenColor.rgb);
 	float chromaDistance = distance(chroma709(color), chroma709(keyColor)) * 2.65;
+	// Direction distance is less sensitive to brightness, while chroma distance
+	// follows broadcast-style color difference; screenBalance blends the two.
 	float directionDistance = length(safeNormalize(max(color, float3(0.0001, 0.0001, 0.0001))) - safeNormalize(max(keyColor, float3(0.0001, 0.0001, 0.0001)))) * 0.55;
 	return lerp(directionDistance, chromaDistance, saturate(screenBalance));
 }
@@ -65,6 +69,8 @@ float refinedAlphaFromMatte(float2 uv, ShaderContext context)

 	if (aaRadius > 0.0001)
 	{
+		// A small fixed kernel smooths edges and collects min/max alpha for
+		// black/white cleanup without needing dynamic loops or arrays.
 		float2 radius = pixel * aaRadius;
 		float2 halfRadius = radius * 0.5;
 		float alphaMin = centerAlpha;
@@ -126,6 +132,8 @@ float refinedAlphaFromMatte(float2 uv, ShaderContext context)
 		alpha = centerAlpha;
 	}

+	// Final matte shaping happens after blur/cleanup so clip and contrast affect
+	// the refined edge rather than the raw screen-distance estimate.
 	alpha = saturate((alpha - clipBlack) / max(clipWhite - clipBlack, 0.0001));
 	alpha = saturate((alpha - 0.5) * max(matteContrast, 0.0001) + 0.5);
 	alpha = pow(max(alpha, 0.0), max(matteGamma, 0.0001));
@@ -135,6 +143,8 @@ float refinedAlphaFromMatte(float2 uv, ShaderContext context)
 float spillAmountForColor(float3 color)
 {
 	float3 keyColor = saturate(screenColor.rgb);
+	// Measure spill as color energy aligned with the screen color minus the
+	// strongest opposing channel, leaving neutral highlights mostly intact.
 	float keyComponent = dot(color, safeNormalize(max(keyColor, float3(0.0001, 0.0001, 0.0001))));
 	float opposingComponent = max(max(color.r * (1.0 - keyColor.r), color.g * (1.0 - keyColor.g)), color.b * (1.0 - keyColor.b));
 	return saturate(keyComponent - opposingComponent + despillBias);
@@ -187,6 +197,8 @@ float4 applyKey(ShaderContext context)
 	float cropMask = cropMaskAt(context.uv, context);
 	alpha *= cropMask;

+	// Edge recovery is strongest around 50% alpha, where fringing usually lives,
+	// and fades away for solid foreground/background pixels.
 	float edgeAmount = saturate(1.0 - abs(alpha * 2.0 - 1.0));
 	despilled = lerp(despilled, despilled * saturate(edgeColor.rgb), edgeAmount * saturate(edgeRecover));

--- a/shaders/happy-accident/shader.slang
+++ b/shaders/happy-accident/shader.slang
@@ -36,6 +36,8 @@ float4 shadeVideo(ShaderContext context)
 	float4 accumulated = float4(0.0, 0.0, 0.0, 0.0);
 	float clampedSteps = clamp(raySteps, 1.0, 77.0);

+	// Ray-march a folded procedural field. distanceToSurface advances the ray,
+	// while inverse-distance accumulation creates the glowing filaments.
 	for (int i = 0; i < 77; ++i)
 	{
 		if (float(i) >= clampedSteps)
@@ -49,11 +51,14 @@ float4 shadeVideo(ShaderContext context)
 		position.xy = mul(rotateAroundZ(2.0 + originalPosition.z), position.xy);
 		position.xy = mul(happyAccidentMatrix(originalPosition, timeCos), position.xy);

+		// Color comes from pre-fold space so the palette varies smoothly even as
+		// the geometry folds into repeated cells.
 		float colorSeed = 0.5 * originalPosition.z + length(position - originalPosition);
 		float4 palette = 1.0 + sin(colorSeed + float4(0.0, 4.0, 3.0, 6.0));
 		palette /= 0.55 + 1.55 * dot(originalPosition.xy, originalPosition.xy);

 		position = abs(frac(position) - 0.5);
+		// Distance to a tiny box/cross primitive inside each repeated cell.
 		distanceToSurface = abs(min(length(position.xy) - 0.125, min(position.x, position.y) + 0.001)) + 0.001;
 		accumulated += palette.w * palette / distanceToSurface;
 	}
--- a/shaders/lut-apply/shader.slang
+++ b/shaders/lut-apply/shader.slang
@@ -7,6 +7,8 @@ float3 sampleLutCell(float3 index)
    float g = floor(index.g + 0.5);
    float b = floor(index.b + 0.5);

+    // The 33^3 cube is packed as blue slices laid horizontally, with red across
+    // each slice and green down the atlas.
    float atlasWidth = LUT_SIZE * LUT_SIZE;
    float2 lutUv;
    lutUv.x = (r + b * LUT_SIZE + 0.5) / atlasWidth;
@@ -30,6 +32,9 @@ float3 applyLut33(float3 color)
    float3 c011 = sampleLutCell(float3(baseIndex.r, nextIndex.g, nextIndex.b));
    float3 c111 = sampleLutCell(float3(nextIndex.r, nextIndex.g, nextIndex.b));

+    // Tetrahedral interpolation chooses one of six paths through the cube.
+    // This avoids the muddy diagonals that simple trilinear LUT sampling can
+    // introduce for strong grades.
    if (blend.r > blend.g)
    {
        if (blend.g > blend.b)
@@ -55,6 +60,8 @@ float hash12(float2 value)

 float3 outputDither(float2 pixel)
 {
+    // Subtract paired hashes to center the dither around zero, then scale to
+    // roughly one 8-bit code value.
    float r = hash12(pixel + float2(17.0, 31.0)) - hash12(pixel + float2(83.0, 47.0));
    float g = hash12(pixel + float2(29.0, 71.0)) - hash12(pixel + float2(53.0, 19.0));
    float b = hash12(pixel + float2(61.0, 11.0)) - hash12(pixel + float2(7.0, 97.0));
--- a/shaders/singularity/shader.slang
+++ b/shaders/singularity/shader.slang
@@ -20,6 +20,8 @@ float4 shadeVideo(ShaderContext context)
 	float2 p = (fragCoord + fragCoord - resolution) / resolution.y / safeScale;
 	p -= center + float2(sin(seed * 6.2831853), cos(seed * 6.2831853)) * 0.035;

+	// Build a skewed coordinate system around an offset "black hole" so the
+	// waves pinch and stretch instead of staying radially symmetric.
 	float iterator = 0.2;
 	float2 diagonal = normalize(float2(-1.0 + seed * 0.5, 1.0 - seed * 0.35));
 	float2 blackholeCenter = p - iterator * diagonal;
@@ -30,6 +32,8 @@ float4 shadeVideo(ShaderContext context)
 	float2 v = singularitySpiral(c, time, iterator);
 	float2 waves = float2(0.0001, 0.0001);

+	// Iterative sine feedback creates the accretion texture; the iterator value
+	// also damps later steps to keep the pattern stable.
 	for (; iterator < 9.0; iterator += 1.0)
 	{
 		waves += 1.0 + sin(v);
@@ -40,6 +44,8 @@ float4 shadeVideo(ShaderContext context)
 	float disk = 2.0 + diskRadius * diskRadius * (0.25 * safeTightness) - diskRadius;
 	float centerDarkness = 0.5 + 1.0 / max(dot(c, c), 0.0001);
 	float rim = 0.025 + abs(length(p) - safeRingRadius) * safeTightness;
+	// Exponential falloff turns the accumulated wave field into bright rims and
+	// a darker center without hard thresholds.
 	float4 redBlueGradient = exp(c.x * float4(0.6, -0.4, -1.0, 0.0) * colorShift);
 	float4 waveColor = waves.xyyx;

--- a/shaders/vhs/shader.json
+++ b/shaders/vhs/shader.json
@@ -69,7 +69,7 @@
      "id": "vignetteAmount",
      "label": "Vignette",
      "type": "float",
-      "default": 0.18,
+      "default": 0.3,
      "min": 0,
      "max": 0.6,
      "step": 0.01,
@@ -154,6 +154,46 @@
      "max": 6,
      "step": 0.05,
      "description": "Scale of the generated noise pattern."
+    },
+    {
+      "id": "scanlineAmount",
+      "label": "Scanlines",
+      "type": "float",
+      "default": 0.08,
+      "min": 0,
+      "max": 0.35,
+      "step": 0.005,
+      "description": "Subtle alternating-field luma modulation."
+    },
+    {
+      "id": "chromaCrawlAmount",
+      "label": "Chroma Crawl",
+      "type": "float",
+      "default": 0.035,
+      "min": 0,
+      "max": 0.2,
+      "step": 0.005,
+      "description": "Moving color shimmer around high-contrast edges."
+    },
+    {
+      "id": "generationLoss",
+      "label": "Generation Loss",
+      "type": "float",
+      "default": 0.18,
+      "min": 0,
+      "max": 1,
+      "step": 0.01,
+      "description": "Raises blacks, softens detail, lowers contrast, and desaturates chroma like copied tape."
+    },
+    {
+      "id": "sharpnessDrift",
+      "label": "Sharpness Drift",
+      "type": "float",
+      "default": 0.12,
+      "min": 0,
+      "max": 0.6,
+      "step": 0.01,
+      "description": "Slowly varies picture softness to mimic unstable tape focus."
    }
  ]
 }
--- a/shaders/vhs/shader.slang
+++ b/shaders/vhs/shader.slang
@@ -8,6 +8,8 @@ float2 jumpy(float2 uv, float framecount)
 	float2 look = uv;
 	float m = frac(framecount / 4.0);
 	float dy = look.y - m;
+	// Localize the horizontal tear to a moving scanline window instead of
+	// bending the whole frame equally.
 	float window = 1.0 / (1.0 + 80.0 * dy * dy);
 	look.x += 0.05 * sin(look.y * 10.0 + framecount) / 20.0 * onOff(4.0, 4.0, 0.3, framecount) * (0.5 + cos(framecount * 20.0)) * window;
 	float vShift = (0.1 * wiggle) * 0.4 * onOff(2.0, 3.0, 0.9, framecount) * (sin(framecount) * sin(framecount * 20.0) + (0.5 + 0.1 * sin(framecount * 200.0) * cos(framecount)));
@@ -44,11 +46,16 @@ float noiseHash(float2 p)
 	return frac(sin(dot(p, float2(127.1, 311.7))) * 43758.5453123);
 }

-// Gold Noise (c)2015 dcerisano@standard3d.com, adapted for Slang.
-float goldNoise(float2 xy, float seed)
+float staticHash(float2 p)
 {
-	const float phi = 1.61803398874989484820459;
-	return frac(tan(distance(xy * phi, xy) * seed) * xy.x);
+	float3 p3 = frac(float3(p.x, p.y, p.x) * 0.1031);
+	p3 += dot(p3, p3.yzx + 33.33);
+	return frac((p3.x + p3.y) * p3.z);
+}
+
+float seededStaticHash(float2 p, float seed)
+{
+	return staticHash(p + float2(seed * 37.13, seed * 17.71));
 }

 float grainScalar(float2 uv)
@@ -59,13 +66,17 @@ float grainScalar(float2 uv)
 float3 animatedChromaGrain(float2 uv, float time, float2 outputResolution, float grainSize)
 {
 	float safeGrainSize = max(grainSize, 0.001);
+	// Quantize the coordinates first so larger grain sizes become visible
+	// chroma blocks rather than simply lower-frequency smooth noise.
 	float2 baseUv = uv * outputResolution * float2(0.85, 0.95) / safeGrainSize;
 	float2 grainUv = floor(baseUv) + 0.5;
-	float2 drift = float2(time * 19.7, time * 23.3);
+	float frame = floor(time * 59.94);

-	float r = grainScalar(grainUv + drift + float2(13.1, 71.7));
-	float g = grainScalar(grainUv * float2(1.03, 0.97) + drift * 1.11 + float2(47.2, 19.4));
-	float b = grainScalar(grainUv * float2(0.96, 1.05) + drift * 0.91 + float2(83.6, 53.8));
+	// Change the grain field per frame instead of drifting it through UV space;
+	// continuous drift can alias into horizontal bands that march down-frame.
+	float r = staticHash(grainUv + float2(frame * 17.0 + 13.1, frame * 3.0 + 71.7));
+	float g = staticHash(grainUv * float2(1.03, 0.97) + float2(frame * 11.0 + 47.2, frame * 5.0 + 19.4));
+	float b = staticHash(grainUv * float2(0.96, 1.05) + float2(frame * 7.0 + 83.6, frame * 13.0 + 53.8));

 	return float3(r, g, b) * 2.0 - 1.0;
 }
@@ -87,6 +98,8 @@ float valueNoise2(float2 p)
 float tapeLineNoise(float2 uv, float time, float2 outputResolution)
 {
 	float y = floor(uv.y * outputResolution.y);
+	// Combine stable per-line noise with frame-rate noise so bands have both
+	// slow tape wander and fast electronic shimmer.
 	float slowLine = valueNoise2(float2(y * 0.021, floor(time * 10.0)));
 	float fastLine = noiseHash(float2(y * 1.73, floor(time * 59.94)));
 	float line = (slowLine * 0.7 + fastLine * 0.3) * 2.0 - 1.0;
@@ -102,16 +115,19 @@ float3 analogStatic(float2 uv, float time, float2 outputResolution)
 	float frame = floor(time * 59.94);
 	float seed = frac(time);

+	// Several differently skewed hashes keep the snow from forming obvious
+	// diagonal or grid patterns at broadcast frame cadence.
 	float2 goldPixel = pixel + float2(0.37, 0.61) + frame;
-	float snowA = goldNoise(goldPixel, seed + 0.1);
-	float snowB = goldNoise(goldPixel * float2(0.37, 2.11) + float2(19.0, 41.0), seed + 0.2);
-	float snowC = goldNoise(goldPixel * float2(1.73, 0.81) + float2(53.0, 7.0), seed + 0.3);
+	float snowA = seededStaticHash(goldPixel, seed + 0.1);
+	float snowB = seededStaticHash(goldPixel * float2(0.37, 2.11) + float2(19.0, 41.0), seed + 0.2);
+	float snowC = seededStaticHash(goldPixel * float2(1.73, 0.81) + float2(53.0, 7.0), seed + 0.3);
 	float snow = (snowA * 0.72 + snowB * 0.28) * 2.0 - 1.0;

 	float lineNoise = tapeLineNoise(uv, time, safeResolution);
-	float dropoutSeed = goldNoise(float2(floor(uv.y * safeResolution.y * 0.25) + 1.0, frame + 2.0), seed + 0.4);
+	float dropoutSeed = seededStaticHash(float2(floor(uv.y * safeResolution.y * 0.25) + 1.0, frame + 2.0), seed + 0.4);
 	float dropout = smoothstep(0.965, 1.0, dropoutSeed);
-	float fleck = smoothstep(0.988, 1.0, snowA) - smoothstep(0.0, 0.012, snowC);
+	float fleckSeed = seededStaticHash(pixel + float2(frame * 13.0, -frame * 7.0), seed + 0.5);
+	float fleck = smoothstep(0.992, 1.0, fleckSeed) - smoothstep(0.0, 0.008, snowC);

 	float scan = sin(uv.y * safeResolution.y * 3.14159265);
 	float scanMask = 0.55 + 0.45 * scan * scan;
@@ -138,6 +154,85 @@ float3 softBloom(float2 uv, float2 outputResolution, float radius)
 	return sum;
 }

+float3 softCrossBlur(float2 uv, float2 outputResolution, float radius)
+{
+	float2 pixel = 1.0 / max(outputResolution, float2(1.0, 1.0));
+	float2 offset = pixel * radius;
+	float3 sum = sampleVideo(frac(uv)).rgb * 0.40;
+	sum += sampleVideo(frac(uv + float2(offset.x, 0.0))).rgb * 0.15;
+	sum += sampleVideo(frac(uv - float2(offset.x, 0.0))).rgb * 0.15;
+	sum += sampleVideo(frac(uv + float2(0.0, offset.y))).rgb * 0.15;
+	sum += sampleVideo(frac(uv - float2(0.0, offset.y))).rgb * 0.15;
+	return sum;
+}
+
+float3 applyChromaCrawl(float3 color, float2 uv, float time, float2 outputResolution)
+{
+	float amount = saturate(chromaCrawlAmount);
+	if (amount <= 0.0001)
+		return color;
+
+	float2 pixel = 1.0 / max(outputResolution, float2(1.0, 1.0));
+	float lumaCenter = dot(color, float3(0.299, 0.587, 0.114));
+	float lumaX = dot(sampleVideo(frac(uv + float2(pixel.x, 0.0))).rgb, float3(0.299, 0.587, 0.114));
+	float lumaY = dot(sampleVideo(frac(uv + float2(0.0, pixel.y))).rgb, float3(0.299, 0.587, 0.114));
+	float edge = saturate((abs(lumaX - lumaCenter) + abs(lumaY - lumaCenter)) * 6.0);
+	float phase = sin(uv.y * outputResolution.y * 1.35 + time * 36.0) * cos(uv.x * outputResolution.x * 0.55 - time * 21.0);
+	float2 crawlOffset = float2(phase, -phase * 0.35) * pixel * (1.0 + amount * 8.0);
+
+	float3 shiftedA = sampleVideo(frac(uv + crawlOffset)).rgb;
+	float3 shiftedB = sampleVideo(frac(uv - crawlOffset * 0.75)).rgb;
+	float3 crawled = color;
+	crawled.r = lerp(color.r, shiftedA.r, edge * amount);
+	crawled.b = lerp(color.b, shiftedB.b, edge * amount);
+	return crawled;
+}
+
+float3 applyGenerationLoss(float3 color, float2 uv, float2 outputResolution)
+{
+	float loss = saturate(generationLoss);
+	if (loss <= 0.0001)
+		return color;
+
+	float3 softened = softCrossBlur(uv, outputResolution, 0.85 + loss * 2.2);
+	color = lerp(color, softened, loss * 0.42);
+
+	float luma = dot(color, float3(0.299, 0.587, 0.114));
+	float3 gray = float3(luma, luma, luma);
+	color = lerp(color, gray, loss * 0.32);
+	color = (color - 0.5) * (1.0 - loss * 0.18) + 0.5;
+	color = color * (1.0 - loss * 0.08) + float3(0.035, 0.035, 0.04) * loss;
+	return color;
+}
+
+float3 applySharpnessDrift(float3 color, float2 uv, float time, float2 outputResolution)
+{
+	float drift = saturate(sharpnessDrift);
+	if (drift <= 0.0001)
+		return color;
+
+	float wobble = 0.5 + 0.5 * sin(time * 1.7 + sin(time * 0.37) * 2.0);
+	float radius = 0.35 + wobble * 2.25;
+	float3 softened = softCrossBlur(uv, outputResolution, radius);
+	return lerp(color, softened, drift * (0.35 + 0.65 * wobble));
+}
+
+float3 applySubtleScanlines(float3 color, float2 uv, float time, float2 outputResolution)
+{
+	float amount = saturate(scanlineAmount);
+	if (amount <= 0.0001)
+		return color;
+
+	float scan = sin((uv.y * outputResolution.y + floor(time * 59.94) * 0.5) * 3.14159265);
+	float field = 0.5 + 0.5 * scan;
+	float luma = dot(color, float3(0.299, 0.587, 0.114));
+	float visibility = lerp(1.0, 0.45, saturate(luma));
+	float modulation = 1.0 - amount * visibility * (0.35 + 0.65 * field);
+	color.rgb *= modulation;
+	color.rgb += amount * 0.015 * (1.0 - field);
+	return color;
+}
+
 float3 blurVhs(float2 uv, float d, int sampleCount)
 {
 	float3 sum = float3(0.0, 0.0, 0.0);
@@ -146,6 +241,8 @@ float3 blurVhs(float2 uv, float d, int sampleCount)
 	float2 pixelOffset = float2(d, 0.0);
 	float2 scale = 0.66 * 8.0 * pixelOffset;

+	// The circular tap pattern approximates soft tape smear while keeping the
+	// maximum loop bound fixed for shader compilation.
 	for (int i = 0; i < 15; ++i)
 	{
 		if (i >= sampleCount)
@@ -170,6 +267,8 @@ float4 buildTapeSmear(ShaderContext context)
 	float framecount = frac(time * wiggleSpeed / 7.0) * 7.0;
 	int sampleCount = int(clamp(blurSamples, 3.0, 15.0) + 0.5);

+	// Split the source into YIQ, smear each component by a different amount,
+	// then recombine to mimic luma/chroma bandwidth mismatch on tape.
 	float d = 0.1 - round(frac(time / 3.0)) * 0.1;
 	uv = jumpy(uv, framecount);
 	float s = 0.0001 * -d + 0.0001 * wiggle * sin(time * wiggleSpeed);
@@ -202,6 +301,8 @@ float4 finishVhs(ShaderContext context)
 	float time = distortedTapeTime(context);
 	float3 color = sampleVideo(context.uv).rgb;

+	// Radial red/blue offsets create lens and deck misregistration before the
+	// wider tape effects are layered in.
 	float2 centered = context.uv * 2.0 - 1.0;
 	centered.x *= context.outputResolution.x / max(context.outputResolution.y, 1.0);
 	float2 aberrationOffset = centered * (aberrationAmount * 0.0015);
@@ -219,16 +320,24 @@ float4 finishVhs(ShaderContext context)
 	float halationMask = smoothstep(0.45, 1.0, halationLuma) * halationAmount;
 	color += halationSource * float3(1.0, 0.38, 0.24) * halationMask * 0.35;

+	// Bloom and fade are applied as separate layers so highlights glow without
+	// flattening the full picture into the faded black level.
 	float3 bloomSource = softBloom(context.uv, context.outputResolution, 2.0 + smear * 2.5);
 	float bloomLuma = dot(bloomSource, float3(0.299, 0.587, 0.114));
 	float bloomMask = smoothstep(0.32, 1.0, bloomLuma) * bloomAmount;
 	color = lerp(color, bloomSource, bloomAmount * 0.18);
 	color += bloomSource * float3(1.0, 0.96, 0.92) * bloomMask * 0.24;

+	color = applySharpnessDrift(color, context.uv, time, context.outputResolution);
+	color = applyGenerationLoss(color, context.uv, context.outputResolution);
+	color = applyChromaCrawl(color, context.uv, time, context.outputResolution);
+
 	float3 speckle = animatedChromaGrain(context.uv, time, context.outputResolution, noiseSize);
 	float luma = dot(color, float3(0.299, 0.587, 0.114));
 	float noiseMask = lerp(0.65, 1.0, 1.0 - saturate(luma));
 	float chunkiness = lerp(1.0, 2.4, saturate((noiseSize - 1.0) / 5.0));
+	// Push darker regions harder: analog noise reads most naturally in shadows
+	// and avoids washing out bright highlights.
 	float3 chromaNoise = float3(speckle.x * 1.2, speckle.y * 0.28, speckle.z * 1.35);
 	color += chromaNoise * noiseAmount * noiseMask * chunkiness;
 	color.rg = lerp(color.rg, float2(color.r, color.g) + speckle.xy * noiseAmount * 0.2 * chunkiness, 0.35);
@@ -244,6 +353,8 @@ float4 finishVhs(ShaderContext context)
 	color = color * (1.0 - fadeAmount * 0.08) + float3(0.055, 0.055, 0.065) * fadeAmount;
 	color = lerp(color, softBloom(context.uv, context.outputResolution, 1.0 + smear), fadeAmount * 0.12);

+	color = applySubtleScanlines(color, context.uv, time, context.outputResolution);
+
 	float vignetteBase = context.uv.x * (1.0 - context.uv.x) * context.uv.y * (1.0 - context.uv.y);
 	float vignette = saturate(pow(vignetteBase * 16.0, 0.22));
 	color *= lerp(1.0 - vignetteAmount, 1.0, vignette);
--- a/shaders/video-cube/shader.slang
+++ b/shaders/video-cube/shader.slang
@@ -17,6 +17,8 @@ bool intersectCube(float3 rayOrigin, float3 rayDirection, float halfExtent, out
 	float3 boxMin = float3(-halfExtent, -halfExtent, -halfExtent);
 	float3 boxMax = float3(halfExtent, halfExtent, halfExtent);

+	// Slab intersection: find the ray interval that overlaps all three box
+	// axes, then keep the nearest positive hit.
 	float3 invDir = 1.0 / rayDirection;
 	float3 t0 = (boxMin - rayOrigin) * invDir;
 	float3 t1 = (boxMax - rayOrigin) * invDir;
@@ -43,6 +45,8 @@ float2 cubeFaceUv(float3 hitPoint, float halfExtent, float zoom)
 	float2 uv = float2(0.5, 0.5);
 	float safeZoom = max(zoom, 0.001);

+	// The dominant coordinate tells which face was hit; the other two axes
+	// become that face's local UVs.
 	if (face.x >= face.y && face.x >= face.z)
 	{
 		uv = hitPoint.x > 0.0
@@ -79,6 +83,8 @@ float4 shadeVideo(ShaderContext context)
 	float yaw = spin;
 	float pitch = spin * 0.61 + 0.35;

+	// Rotate the camera ray into cube-local space instead of rotating the cube
+	// geometry, which keeps the intersection math axis-aligned.
 	float3 localOrigin = rotateY(rotateX(rayOrigin, -pitch), -yaw);
 	float3 localDirection = rotateY(rotateX(rayDirection, -pitch), -yaw);

@@ -96,6 +102,8 @@ float4 shadeVideo(ShaderContext context)

 	float3 normal;
 	float3 face = abs(localHit);
+	// Reconstruct the face normal from the hit point so lighting follows the
+	// same face choice used for UV lookup.
 	if (face.x >= face.y && face.x >= face.z)
 		normal = float3(sign(localHit.x), 0.0, 0.0);
 	else if (face.y >= face.x && face.y >= face.z)
--- a/shaders/video-plane-3d/shader.json
+++ b/shaders/video-plane-3d/shader.json
@@ -0,0 +1,121 @@
+{
+  "id": "video-plane-3d",
+  "name": "Video Plane 3D",
+  "description": "Places the video on a perspective 2D plane in 3D space with camera FOV, XYZ position, and pan/tilt/roll controls.",
+  "category": "Projection",
+  "entryPoint": "shadeVideo",
+  "parameters": [
+    {
+      "id": "fovDegrees",
+      "label": "FOV",
+      "type": "float",
+      "default": 45,
+      "min": 5,
+      "max": 150,
+      "step": 0.1,
+      "description": "Virtual camera vertical field of view in degrees."
+    },
+    {
+      "id": "positionX",
+      "label": "X",
+      "type": "float",
+      "default": 0,
+      "min": -4,
+      "max": 4,
+      "step": 0.01,
+      "description": "Horizontal plane position in world units."
+    },
+    {
+      "id": "positionY",
+      "label": "Y",
+      "type": "float",
+      "default": 0,
+      "min": -4,
+      "max": 4,
+      "step": 0.01,
+      "description": "Vertical plane position in world units."
+    },
+    {
+      "id": "positionZ",
+      "label": "Z",
+      "type": "float",
+      "default": 2.2,
+      "min": 0.1,
+      "max": 10,
+      "step": 0.01,
+      "description": "Depth of the plane in front of the virtual camera."
+    },
+    {
+      "id": "panDegrees",
+      "label": "Pan",
+      "type": "float",
+      "default": 0,
+      "min": -180,
+      "max": 180,
+      "step": 0.1,
+      "description": "Rotates the plane left/right around its vertical axis."
+    },
+    {
+      "id": "tiltDegrees",
+      "label": "Tilt",
+      "type": "float",
+      "default": 0,
+      "min": -120,
+      "max": 120,
+      "step": 0.1,
+      "description": "Rotates the plane up/down around its horizontal axis."
+    },
+    {
+      "id": "rollDegrees",
+      "label": "Roll",
+      "type": "float",
+      "default": 0,
+      "min": -180,
+      "max": 180,
+      "step": 0.1,
+      "description": "Rotates the plane around its face normal."
+    },
+    {
+      "id": "planeScale",
+      "label": "Plane Scale",
+      "type": "float",
+      "default": 1.4,
+      "min": 0.05,
+      "max": 6,
+      "step": 0.01,
+      "description": "Height of the video plane in world units; width follows the source aspect ratio."
+    },
+    {
+      "id": "edgeFeather",
+      "label": "Edge Feather",
+      "type": "float",
+      "default": 1.5,
+      "min": 0,
+      "max": 24,
+      "step": 0.1,
+      "description": "Softens the plane edge in source pixels."
+    },
+    {
+      "id": "backgroundMix",
+      "label": "Background Mix",
+      "type": "float",
+      "default": 0,
+      "min": 0,
+      "max": 1,
+      "step": 0.01,
+      "description": "Mixes the original video behind the projected plane."
+    },
+    {
+      "id": "outsideColor",
+      "label": "Outside Color",
+      "type": "color",
+      "default": [
+        0,
+        0,
+        0,
+        1
+      ],
+      "description": "Color used where the camera ray misses the plane."
+    }
+  ]
+}
--- a/shaders/video-plane-3d/shader.slang
+++ b/shaders/video-plane-3d/shader.slang
@@ -0,0 +1,84 @@
+static const float PI = 3.14159265358979323846;
+
+float radiansFromDegrees(float degrees)
+{
+	return degrees * (PI / 180.0);
+}
+
+float3 rotateX(float3 p, float angle)
+{
+	float s = sin(angle);
+	float c = cos(angle);
+	return float3(p.x, c * p.y - s * p.z, s * p.y + c * p.z);
+}
+
+float3 rotateY(float3 p, float angle)
+{
+	float s = sin(angle);
+	float c = cos(angle);
+	return float3(c * p.x + s * p.z, p.y, -s * p.x + c * p.z);
+}
+
+float3 rotateZ(float3 p, float angle)
+{
+	float s = sin(angle);
+	float c = cos(angle);
+	return float3(c * p.x - s * p.y, s * p.x + c * p.y, p.z);
+}
+
+float3 rotateWorldToPlane(float3 value)
+{
+	float pan = radiansFromDegrees(panDegrees);
+	float tilt = radiansFromDegrees(tiltDegrees);
+	float roll = radiansFromDegrees(rollDegrees);
+	return rotateZ(rotateX(rotateY(value, -pan), -tilt), -roll);
+}
+
+float planeEdgeMask(float2 uv, float2 inputResolution)
+{
+	float2 feather = max(edgeFeather, 0.0) / max(inputResolution, float2(1.0, 1.0));
+	feather = max(feather, float2(0.00001, 0.00001));
+
+	float left = smoothstep(0.0, feather.x, uv.x);
+	float right = 1.0 - smoothstep(1.0 - feather.x, 1.0, uv.x);
+	float top = smoothstep(0.0, feather.y, uv.y);
+	float bottom = 1.0 - smoothstep(1.0 - feather.y, 1.0, uv.y);
+	return saturate(left * right * top * bottom);
+}
+
+float4 shadeVideo(ShaderContext context)
+{
+	float2 outputResolution = max(context.outputResolution, float2(1.0, 1.0));
+	float outputAspect = outputResolution.x / outputResolution.y;
+	float sourceAspect = context.inputResolution.x / max(context.inputResolution.y, 1.0);
+	float tanHalfFov = tan(radiansFromDegrees(clamp(fovDegrees, 5.0, 150.0)) * 0.5);
+
+	float2 screen = float2(context.uv.x * 2.0 - 1.0, 1.0 - context.uv.y * 2.0);
+	float3 rayOrigin = float3(0.0, 0.0, 0.0);
+	float3 rayDirection = normalize(float3(screen.x * outputAspect * tanHalfFov, screen.y * tanHalfFov, 1.0));
+
+	float3 planePosition = float3(positionX, positionY, max(positionZ, 0.001));
+	float3 localOrigin = rotateWorldToPlane(rayOrigin - planePosition);
+	float3 localDirection = rotateWorldToPlane(rayDirection);
+
+	float backgroundAmount = saturate(backgroundMix);
+	float4 background = float4(lerp(outsideColor.rgb, context.sourceColor.rgb, backgroundAmount), 1.0);
+	if (abs(localDirection.z) < 0.00001)
+		return background;
+
+	float hitDistance = -localOrigin.z / localDirection.z;
+	if (hitDistance <= 0.0)
+		return background;
+
+	float3 localHit = localOrigin + localDirection * hitDistance;
+	float halfHeight = max(planeScale, 0.001) * 0.5;
+	float halfWidth = halfHeight * sourceAspect;
+	float2 planeUv = float2(
+		localHit.x / max(halfWidth * 2.0, 0.0001) + 0.5,
+		0.5 - localHit.y / max(halfHeight * 2.0, 0.0001)
+	);
+
+	float mask = planeEdgeMask(planeUv, max(context.inputResolution, float2(1.0, 1.0)));
+	float4 planeColor = sampleVideo(clamp(planeUv, 0.0, 1.0));
+	return saturate(lerp(background, planeColor, mask));
+}
--- a/shaders/video-transform/shader.json
+++ b/shaders/video-transform/shader.json
@@ -47,6 +47,35 @@
      "step": 0.1,
      "description": "Rotates the source image around the frame center."
    },
+    {
+      "id": "cropAspect",
+      "label": "Crop Aspect",
+      "type": "enum",
+      "default": "none",
+      "options": [
+        {
+          "value": "none",
+          "label": "None"
+        },
+        {
+          "value": "4x3",
+          "label": "4:3"
+        },
+        {
+          "value": "3x2",
+          "label": "3:2"
+        },
+        {
+          "value": "1x1",
+          "label": "1:1"
+        },
+        {
+          "value": "9x16",
+          "label": "9:16"
+        }
+      ],
+      "description": "Crops the visible image to a centered preset aspect ratio without squeezing the source."
+    },
    {
      "id": "edgeMode",
      "label": "Edge Mode",
--- a/shaders/video-transform/shader.slang
+++ b/shaders/video-transform/shader.slang
@@ -28,8 +28,42 @@ float2 applyEdgeMode(float2 uv, out bool inside)
 	return uv;
 }

+float selectedCropAspect()
+{
+	if (cropAspect == 1)
+		return 4.0 / 3.0;
+	if (cropAspect == 2)
+		return 3.0 / 2.0;
+	if (cropAspect == 3)
+		return 1.0;
+	if (cropAspect == 4)
+		return 9.0 / 16.0;
+	return 0.0;
+}
+
+bool insideCropWindow(float2 uv, float2 resolution)
+{
+	float targetAspect = selectedCropAspect();
+	if (targetAspect <= 0.0)
+		return true;
+
+	float outputAspect = resolution.x / max(resolution.y, 1.0);
+	float2 cropSize = float2(1.0, 1.0);
+	if (outputAspect > targetAspect)
+		cropSize.x = targetAspect / outputAspect;
+	else
+		cropSize.y = outputAspect / targetAspect;
+
+	float2 cropMin = (1.0 - cropSize) * 0.5;
+	float2 cropMax = cropMin + cropSize;
+	return uv.x >= cropMin.x && uv.x <= cropMax.x && uv.y >= cropMin.y && uv.y <= cropMax.y;
+}
+
 float4 shadeVideo(ShaderContext context)
 {
+	if (!insideCropWindow(context.uv, max(context.outputResolution, float2(1.0, 1.0))))
+		return outsideColor;
+
 	float safeZoom = max(zoom, 0.001);
 	float2 sourceUv = (context.uv - 0.5) / safeZoom + 0.5;
 	sourceUv -= pan;
--- a/shaders/waveform-overlay/shader.slang
+++ b/shaders/waveform-overlay/shader.slang
@@ -18,6 +18,8 @@ float4 shadeVideo(ShaderContext context)
 	float resolutionAspect = max(context.outputResolution.x, 1.0) / max(context.outputResolution.y, 1.0);
 	float width = saturate(overlayScale);
 	float height = width * resolutionAspect / targetAspect;
+	// Keep the scope in a 16:9 frame, then shrink it if the requested scale
+	// would push the overlay beyond the screen bounds.
 	float fitScale = min(1.0 / max(width, 0.001), 1.0 / max(height, 0.001));
 	width *= min(fitScale, 1.0);
 	height *= min(fitScale, 1.0);
@@ -36,6 +38,8 @@ float4 shadeVideo(ShaderContext context)

 	float3 bg = lerp(color.rgb, float3(0.0, 0.0, 0.0), saturate(backgroundOpacity));
 	float labelHeight = min(max(pad.x * 0.95, 0.048), 0.12);
+	// Label textures are authored in UV space, so compensate for the overlay
+	// and output aspect ratios to keep the glyphs from stretching.
 	float labelWidth = labelHeight * height * max(context.outputResolution.y, 1.0) / max(width * max(context.outputResolution.x, 1.0), 0.001);
 	float labelX = max(pad.x * 0.5, labelWidth * 0.55);
 	float y0 = pad.y;
@@ -63,6 +67,8 @@ float4 shadeVideo(ShaderContext context)
 	float requestedSamples = clamp(waveformSamples, 1.0, 96.0);
 	float density = 0.0;

+	// For each output pixel, march through source rows at the same X coordinate
+	// and accumulate hits where sampled luma lands near this pixel's Y level.
 	for (int sampleIndex = 0; sampleIndex < 96; sampleIndex++)
 	{
 		float samplePosition = float(sampleIndex);
--- a/shaders/xyla-exposure-chart/shader.slang
+++ b/shaders/xyla-exposure-chart/shader.slang
@@ -1,5 +1,7 @@
 float boxMask(float2 point, float2 halfSize, float feather)
 {
+	// Signed-distance box mask gives the chart and border pixel-sized feathered
+	// edges without branching per side.
 	float2 distanceToEdge = abs(point) - halfSize;
 	float outsideDistance = length(max(distanceToEdge, float2(0.0, 0.0)));
 	float insideDistance = min(max(distanceToEdge.x, distanceToEdge.y), 0.0);
@@ -31,6 +33,8 @@ float applyToneCurve(float linearLevel)
 float patchBrightness(int patchIndex, int count)
 {
 	int clampedIndex = clamp(patchIndex, 0, max(count - 1, 0));
+	// Each patch is one stop brighter than the previous patch until it clips at
+	// the requested peak level, matching the Xyla-style exposure ramp.
 	float linearLevel = baseLevel * exp2(float(clampedIndex));
 	linearLevel = min(linearLevel, peakLevel);
 	return applyToneCurve(linearLevel);
@@ -60,6 +64,8 @@ float4 shadeVideo(ShaderContext context)
 	if (reverseOrder)
 		patchIndex = count - 1 - patchIndex;

+	// Build each patch as a slot along the main axis, then mask the cross-axis
+	// extents so vertical and horizontal charts share the same logic.
 	float patchSlotCenter = (floor(patchPosition) + 0.5) / float(count);
 	float localAxis = abs(normalizedAxis - patchSlotCenter) * float(count) * 2.0;
 	float safeGapSize = saturate(gapSize);
--- a/tests/RuntimeHostVideoIOStateTests.cpp
+++ b/tests/RuntimeHostVideoIOStateTests.cpp
@@ -0,0 +1,67 @@
+#include "RuntimeHost.h"
+
+#include <iostream>
+
+namespace
+{
+int gFailures = 0;
+
+void Expect(bool condition, const char* message)
+{
+	if (condition)
+		return;
+
+	std::cerr << "FAIL: " << message << "\n";
+	++gFailures;
+}
+}
+
+int main()
+{
+	RuntimeHost runtimeHost;
+	std::string error;
+	Expect(runtimeHost.Initialize(error), "runtime host initializes");
+	Expect(error.empty(), "runtime host initialization does not report an error");
+
+	VideoIOState state;
+	state.backendId = VideoIOBackendId::DeckLink;
+	state.deviceName = "Test Device";
+	state.hasInputDevice = true;
+	state.hasInputSource = true;
+	state.inputDisplayModeName = "fake input";
+	state.outputDisplayModeName = "fake output";
+	state.capabilities.supportsInternalKeying = true;
+	state.capabilities.supportsExternalKeying = true;
+	state.capabilities.keyerInterfaceAvailable = true;
+	state.externalKeyingRequested = true;
+	state.externalKeyingActive = true;
+	state.statusMessage = "ready";
+	state.formatStatusMessage = "using fake formats";
+	runtimeHost.SetVideoIOStatus(state);
+
+	JsonValue root;
+	Expect(ParseJson(runtimeHost.BuildStateJson(), root, error), "runtime state json parses");
+	Expect(root.find("videoIO") != nullptr, "runtime state exposes videoIO");
+	Expect(root.find("decklink") == nullptr, "runtime state no longer exposes a decklink top-level block");
+
+	const JsonValue* app = root.find("app");
+	Expect(app != nullptr, "runtime state exposes app settings");
+	Expect(app != nullptr && app->find("videoBackend") != nullptr, "app settings expose videoBackend");
+	Expect(app != nullptr && app->find("videoBackend")->asString() == "decklink", "videoBackend serializes as decklink");
+
+	const JsonValue* videoIO = root.find("videoIO");
+	Expect(videoIO != nullptr && videoIO->find("backend") != nullptr, "videoIO exposes backend");
+	Expect(videoIO != nullptr && videoIO->find("backend")->asString() == "decklink", "videoIO backend serializes as decklink");
+	Expect(videoIO != nullptr && videoIO->find("deviceName") != nullptr, "videoIO exposes device name");
+	Expect(videoIO != nullptr && videoIO->find("deviceName")->asString() == "Test Device", "videoIO device name matches");
+	Expect(videoIO != nullptr && videoIO->find("capabilities") != nullptr, "videoIO exposes capabilities");
+
+	if (gFailures != 0)
+	{
+		std::cerr << gFailures << " RuntimeHost video I/O state test failure(s).\n";
+		return 1;
+	}
+
+	std::cout << "RuntimeHost video I/O state tests passed.\n";
+	return 0;
+}
--- a/tests/VideoIOBackendFactoryTests.cpp
+++ b/tests/VideoIOBackendFactoryTests.cpp
@@ -0,0 +1,41 @@
+#include "VideoIOBackendFactory.h"
+#include "VideoIOTypes.h"
+
+#include <iostream>
+
+namespace
+{
+int gFailures = 0;
+
+void Expect(bool condition, const char* message)
+{
+	if (condition)
+		return;
+
+	std::cerr << "FAIL: " << message << "\n";
+	++gFailures;
+}
+}
+
+int main()
+{
+	std::string error;
+	std::unique_ptr<VideoIODevice> device = CreateVideoIODevice(VideoIOBackendId::DeckLink, error);
+	Expect(device != nullptr, "decklink backend factory returns a device");
+	Expect(!device || device->BackendId() == VideoIOBackendId::DeckLink, "decklink backend reports decklink id");
+	Expect(error.empty(), "supported backend does not produce an error");
+
+	error.clear();
+	device = CreateVideoIODevice(static_cast<VideoIOBackendId>(999), error);
+	Expect(device == nullptr, "unknown backend id is rejected");
+	Expect(!error.empty(), "unknown backend reports an error");
+
+	if (gFailures != 0)
+	{
+		std::cerr << gFailures << " VideoIO backend factory test failure(s).\n";
+		return 1;
+	}
+
+	std::cout << "VideoIO backend factory tests passed.\n";
+	return 0;
+}
--- a/tests/VideoIODeviceFakeTests.cpp
+++ b/tests/VideoIODeviceFakeTests.cpp
@@ -19,20 +19,26 @@ void Expect(bool condition, const char* message)
 class FakeVideoIODevice : public VideoIODevice
 {
 public:
+	VideoIOBackendId BackendId() const override { return VideoIOBackendId::DeckLink; }
 	void ReleaseResources() override {}

-	bool DiscoverDevicesAndModes(const VideoFormatSelection&, std::string&) override
+	bool DiscoverDevicesAndModes(const VideoIOConfiguration&, std::string&) override
 	{
+		mState.backendId = BackendId();
 		mState.inputFrameSize = { 1920, 1080 };
 		mState.outputFrameSize = { 1920, 1080 };
 		mState.inputDisplayModeName = "fake 1080p";
-		mState.outputModelName = "Fake Video IO";
+		mState.outputDisplayModeName = "fake 1080p";
+		mState.deviceName = "Fake Video IO";
+		mState.capabilities.supportsInternalKeying = true;
+		mState.capabilities.supportsExternalKeying = true;
 		mState.hasInputDevice = true;
 		return true;
 	}

-	bool SelectPreferredFormats(const VideoFormatSelection&, bool, std::string&) override
+	bool SelectPreferredFormats(const VideoIOConfiguration& config, std::string&) override
 	{
+		mState.externalKeyingRequested = config.externalKeyingEnabled;
 		mState.inputPixelFormat = VideoIOPixelFormat::Uyvy8;
 		mState.outputPixelFormat = VideoIOPixelFormat::Bgra8;
 		mState.inputFrameRowBytes = VideoIORowBytes(mState.inputPixelFormat, mState.inputFrameSize.width);
@@ -42,13 +48,13 @@ public:
 		return true;
 	}

-	bool ConfigureInput(InputFrameCallback callback, const VideoFormat&, std::string&) override
+	bool ConfigureInput(InputFrameCallback callback, std::string&) override
 	{
 		mInputCallback = callback;
 		return true;
 	}

-	bool ConfigureOutput(OutputFrameCallback callback, const VideoFormat&, bool, std::string&) override
+	bool ConfigureOutput(OutputFrameCallback callback, std::string&) override
 	{
 		mOutputCallback = callback;
 		return true;
@@ -114,19 +120,19 @@ private:
 int main()
 {
 	FakeVideoIODevice device;
-	VideoFormatSelection selection;
+	VideoIOConfiguration config;
 	std::string error;
 	bool inputSeen = false;
 	bool outputSeen = false;

-	Expect(device.DiscoverDevicesAndModes(selection, error), "fake discovery succeeds");
-	Expect(device.SelectPreferredFormats(selection, false, error), "fake format selection succeeds");
+	Expect(device.DiscoverDevicesAndModes(config, error), "fake discovery succeeds");
+	Expect(device.SelectPreferredFormats(config, error), "fake format selection succeeds");
 	Expect(device.ConfigureInput([&](const VideoIOFrame& frame) {
 		inputSeen = frame.bytes != nullptr && frame.width == 1920 && frame.pixelFormat == VideoIOPixelFormat::Uyvy8;
-	}, selection.input, error), "fake input config succeeds");
+	}, error), "fake input config succeeds");
 	Expect(device.ConfigureOutput([&](const VideoIOCompletion& completion) {
 		outputSeen = completion.result == VideoIOCompletionResult::Completed;
-	}, selection.output, false, error), "fake output config succeeds");
+	}, error), "fake output config succeeds");
 	Expect(device.Start(), "fake device starts");

 	VideoIOOutputFrame outputFrame;
Author	SHA1	Message	Date
Aiden	0c16665610	Revert "Decklink separation" Some checks failed CI / Windows Release Package (push) Has been cancelled Details CI / React UI Build (push) Has been cancelled Details CI / Native Windows Build And Tests (push) Has been cancelled Details This reverts commit `46f2f1ece5`.	2026-05-09 16:47:33 +10:00
Aiden	46f2f1ece5	Decklink separation	2026-05-09 14:42:11 +10:00
Aiden	4ffbb97abf	Video backend All checks were successful CI / React UI Build (push) Successful in 11s Details CI / Native Windows Build And Tests (push) Successful in 2m43s Details CI / Windows Release Package (push) Successful in 2m54s Details	2026-05-09 14:15:49 +10:00
Aiden	98f5cbe309	preview changes All checks were successful CI / React UI Build (push) Successful in 11s Details CI / Native Windows Build And Tests (push) Successful in 2m23s Details CI / Windows Release Package (push) Successful in 2m41s Details	2026-05-09 13:53:00 +10:00
Aiden	93d856b3b6	CPU optimisations Some checks failed CI / React UI Build (push) Successful in 37s Details CI / Windows Release Package (push) Has been cancelled Details CI / Native Windows Build And Tests (push) Has been cancelled Details	2026-05-09 13:50:27 +10:00
Aiden	6ea6971dd6	more shaders and updates/changes All checks were successful CI / React UI Build (push) Successful in 10s Details CI / Native Windows Build And Tests (push) Successful in 2m22s Details CI / Windows Release Package (push) Successful in 2m35s Details	2026-05-08 20:32:19 +10:00
Aiden	163d70e9bd	Annotations All checks were successful CI / React UI Build (push) Successful in 11s Details CI / Native Windows Build And Tests (push) Successful in 2m22s Details CI / Windows Release Package (push) Successful in 2m28s Details	2026-05-08 20:01:22 +10:00
Aiden	8afef5065a	Update README.md All checks were successful CI / React UI Build (push) Successful in 11s Details CI / Native Windows Build And Tests (push) Successful in 2m20s Details CI / Windows Release Package (push) Successful in 2m34s Details	2026-05-08 19:14:31 +10:00