diff --git a/nodes/decklinkin/main.cpp b/nodes/decklinkin/main.cpp
index 956ceb3..de81b38 100644
--- a/nodes/decklinkin/main.cpp
+++ b/nodes/decklinkin/main.cpp
@@ -8,15 +8,19 @@
 
 class DeckLinkInNode : public dmf::NodeBase {
     void run() override {
-        dmf::DeckLinkReceiver receiver;
-
-        log("Available DeckLink devices:");
-        for (const auto& d : receiver.devices)
-            log("  %u) %s", d.index, d.name.c_str());
-
         const uint32_t device_index = config().value("device_index", 0u);
-        receiver.start_capture(device_index);
-        log("Capturing from: %s", receiver.devices[device_index].name.c_str());
+
+        dmf::DeckLinkReceiver receiver;
+        try {
+            log("Available DeckLink devices:");
+            for (const auto& d : receiver.devices)
+                log("  %u) %s", d.index, d.name.c_str());
+            receiver.start_capture(device_index);
+            log("Capturing from: %s", receiver.devices[device_index].name.c_str());
+        } catch (const std::runtime_error& e) {
+            log("DeckLink init error: %s", e.what());
+            return;
+        }
 
         if (!receiver.wait_for_format(5000)) {
             log("Timeout waiting for format detection");
@@ -55,7 +59,7 @@ class DeckLinkInNode : public dmf::NodeBase {
         uint64_t          video_index = mxlGetCurrentIndex(&video_rate);
         log("start video_index=%llu", video_index);
 
-        std::vector<uint8_t> frame_buf(static_cast<size_t>(video_stride) * static_cast<size_t>(height), 0);
+        std::vector<uint8_t> frame_buf(static_cast<size_t>(video_stride) * static_cast<size_t>(height));
 
         while (dmf::g_running.load(std::memory_order_relaxed)) {
             if (!receiver.wait_for_frame(frame_buf.data(), video_stride, width, height)) break;
diff --git a/shared/DeckLinkReceiver.hpp b/shared/DeckLinkReceiver.hpp
index 5afc2dc..c463fe5 100644
--- a/shared/DeckLinkReceiver.hpp
+++ b/shared/DeckLinkReceiver.hpp
@@ -68,7 +68,7 @@ public:
         if (r != S_OK) throw std::runtime_error("Could not start streams");
     }
 
-    bool wait_for_format(uint64_t timeout_ms = 5000) {
+    bool wait_for_format(int timeout_ms = 5000) {
         std::unique_lock<std::mutex> lk(mutex);
         return format_cv.wait_for(lk, std::chrono::milliseconds(timeout_ms),
             [this] { return format_detected; });
@@ -173,16 +173,19 @@ private:
         std::atomic<int32_t> ref_count{1};
     };
 
+    // DeckLink SDK objects
     std::vector<IDeckLink*>  raw_devices;
     IDeckLink*               selected_device = nullptr;
     IDeckLinkInput*          decklink_input  = nullptr;
     InputCallback*           input_callback  = nullptr;
 
+    // Synchronisation — one mutex guards all shared state below
     std::mutex              mutex;
-    std::condition_variable format_cv;
-    std::condition_variable frame_cv;
+    std::condition_variable format_cv;   // signalled when format is detected
+    std::condition_variable frame_cv;    // signalled when a frame arrives
     bool                    format_detected = false;
 
+    // Frame state — written by InputCallback, read by wait_for_frame (both under mutex)
     std::vector<uint8_t>    frame_buffer;
     uint32_t                frame_row_bytes = 0;
     int                     frame_width     = 0;