NDI discovery

src/video/ndi/NdiOutput.cpp

@@ -148,11 +148,6 @@ bool NdiOutput::Initialize(const VideoOutputEdgeConfig& config, CompletionCallba
 		return false;
 	}
 
-	if (config.outputAlphaRequired)
-	{
-		mState.statusMessage = "NDI output can carry BGRA alpha when configured; output.keying.alphaRequired is a DeckLink-only requirement.";
-	}
-
 	if (!AcquireNdiRuntime())
 	{
 		error = "NDI runtime initialization failed. The CPU/runtime might not support NDI.";
@@ -175,6 +170,8 @@ bool NdiOutput::Initialize(const VideoOutputEdgeConfig& config, CompletionCallba
 
 	mInitialized.store(true, std::memory_order_release);
 	mState.statusMessage = "NDI output sender '" + mSenderName + "' initialized.";
+	if (config.outputAlphaRequired)
+		mState.statusMessage += " Output alpha is enabled; external keying is ignored for NDI.";
 	Log("ndi-output", mState.statusMessage);
 	return true;
 }

src/video/ndi/NdiSourceDiscovery.cpp

@@ -0,0 +1,72 @@
+#include "NdiSourceDiscovery.h"
+
+#include "NdiRuntime.h"
+
+#include <Processing.NDI.Lib.h>
+
+#include <algorithm>
+#include <cstring>
+#include <utility>
+
+namespace RenderCadenceCompositor
+{
+bool DiscoverNdiSources(std::vector<NdiSourceInfo>& sources, std::string& error, uint32_t waitMilliseconds)
+{
+	sources.clear();
+	if (!AcquireNdiRuntime())
+	{
+		error = "NDI runtime initialization failed. The CPU/runtime might not support NDI.";
+		return false;
+	}
+
+	NDIlib_find_create_t settings;
+	std::memset(&settings, 0, sizeof(settings));
+	settings.show_local_sources = true;
+
+	NDIlib_find_instance_t finder = NDIlib_find_create_v2(&settings);
+	if (finder == nullptr)
+	{
+		ReleaseNdiRuntime();
+		error = "NDI source finder creation failed.";
+		return false;
+	}
+
+	uint32_t sourceCount = 0;
+	const NDIlib_source_t* ndiSources = NDIlib_find_get_current_sources(finder, &sourceCount);
+	if (sourceCount == 0 && waitMilliseconds > 0)
+	{
+		NDIlib_find_wait_for_sources(finder, waitMilliseconds);
+		ndiSources = NDIlib_find_get_current_sources(finder, &sourceCount);
+	}
+
+	if (ndiSources != nullptr)
+	{
+		sources.reserve(sourceCount);
+		for (uint32_t index = 0; index < sourceCount; ++index)
+		{
+			const char* name = ndiSources[index].p_ndi_name;
+			if (name == nullptr || name[0] == '\0')
+				continue;
+
+			NdiSourceInfo source;
+			source.name = name;
+			if (ndiSources[index].p_url_address != nullptr)
+				source.urlAddress = ndiSources[index].p_url_address;
+			sources.push_back(std::move(source));
+		}
+	}
+
+	NDIlib_find_destroy(finder);
+	ReleaseNdiRuntime();
+
+	std::sort(sources.begin(), sources.end(), [](const NdiSourceInfo& lhs, const NdiSourceInfo& rhs) {
+		return lhs.name < rhs.name;
+	});
+	sources.erase(std::unique(sources.begin(), sources.end(), [](const NdiSourceInfo& lhs, const NdiSourceInfo& rhs) {
+		return lhs.name == rhs.name;
+	}), sources.end());
+
+	error.clear();
+	return true;
+}
+}

src/video/ndi/NdiSourceDiscovery.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+#include <vector>
+
+namespace RenderCadenceCompositor
+{
+struct NdiSourceInfo
+{
+	std::string name;
+	std::string urlAddress;
+};
+
+bool DiscoverNdiSources(std::vector<NdiSourceInfo>& sources, std::string& error, uint32_t waitMilliseconds = 250);
+}