refactor: use static COM init in MSMF backend to avoid thread-affinity issues

Replace per-instance m_didInitializeCom/m_didSetup flags with a static
setupCom pattern matching the DirectShow backend. Removes CoUninitialize
from the destructor since static COM init is never paired with uninit,
avoiding mismatched init/uninit on different threads.

Author: wysaid

src/ccap_imp_windows_msmf.cpp

@@ -152,22 +152,23 @@ ProviderMSMF::ProviderMSMF() {
 ProviderMSMF::~ProviderMSMF() {
     close();
     uninitMediaFoundation();
-    if (m_didInitializeCom) {
-        CoUninitialize();
-        m_didInitializeCom = false;
-    }
 }
 
 bool ProviderMSMF::setup() {
     if (m_mfInitialized) {
         return true;
     }
 
-    if (!m_didSetup) {
+    // Use static COM initialization (matching DirectShow backend pattern).
+    // COM init/uninit is thread-affine — caching per-instance flags can
+    // mismatch if the destructor runs on a different thread.  A static
+    // flag avoids the issue and is safe because COM reference-counts its
+    // per-thread initialization.
+    static bool s_didSetup = false;
+    if (!s_didSetup) {
         HRESULT hr = CoInitializeEx(nullptr, COINIT_MULTITHREADED);
-        m_didInitializeCom = SUCCEEDED(hr);
-        m_didSetup = m_didInitializeCom || hr == RPC_E_CHANGED_MODE;
-        if (!m_didSetup) {
+        s_didSetup = SUCCEEDED(hr) || hr == RPC_E_CHANGED_MODE;
+        if (!s_didSetup) {
             reportError(ErrorCode::InitializationFailed, "COM initialization failed for Media Foundation backend");
             return false;
         }

src/ccap_imp_windows_msmf.h

@@ -81,8 +81,6 @@ class ProviderMSMF : public ProviderImp {
     std::atomic<bool> m_shouldStop{ false };
     std::atomic<bool> m_isRunning{ false };
     bool m_isOpened{ false };
-    bool m_didSetup{ false };
-    bool m_didInitializeCom{ false };
     bool m_mfInitialized{ false };
     PixelFormat m_activePixelFormat = PixelFormat::Unknown;
     uint32_t m_activeWidth = 0;