Adjust thread priorities based on recent refactoring

app/streaming/session.cpp

@@ -1007,14 +1007,6 @@ void Session::exec(int displayOriginX, int displayOriginY)
     // sleep precision and more accurate callback timing.
     SDL_SetHint(SDL_HINT_TIMER_RESOLUTION, "1");
 
-    // Raise the priority of the main thread, since it handles
-    // time-sensitive video rendering
-    if (SDL_SetThreadPriority(SDL_THREAD_PRIORITY_HIGH) < 0) {
-        SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
-                    "Unable to set main thread to high priority: %s",
-                    SDL_GetError());
-    }
-
     int currentDisplayIndex = SDL_GetWindowDisplayIndex(m_Window);
 
     // Now that we're about to stream, any SDL_QUIT event is expected

app/streaming/video/ffmpeg-renderers/pacer/dxvsyncsource.cpp

@@ -76,7 +76,11 @@ int DxVsyncSource::vsyncThread(void* context)
 {
     DxVsyncSource* me = reinterpret_cast<DxVsyncSource*>(context);
 
+#if SDL_VERSION_ATLEAST(2, 0, 9)
+    SDL_SetThreadPriority(SDL_THREAD_PRIORITY_TIME_CRITICAL);
+#else
     SDL_SetThreadPriority(SDL_THREAD_PRIORITY_HIGH);
+#endif
 
     D3DKMT_OPENADAPTERFROMHDC openAdapterParams = {};
     HMONITOR lastMonitor = nullptr;

app/streaming/video/ffmpeg-renderers/pacer/nullthreadedvsyncsource.cpp

@@ -33,7 +33,11 @@ int NullThreadedVsyncSource::vsyncThread(void* context)
 {
     NullThreadedVsyncSource* me = reinterpret_cast<NullThreadedVsyncSource*>(context);
 
+#if SDL_VERSION_ATLEAST(2, 0, 9)
+    SDL_SetThreadPriority(SDL_THREAD_PRIORITY_TIME_CRITICAL);
+#else
     SDL_SetThreadPriority(SDL_THREAD_PRIORITY_HIGH);
+#endif;
 
     while (SDL_AtomicGet(&me->m_Stopping) == 0) {
         me->m_Pacer->vsyncCallback(1000 / me->m_DisplayFps);

app/streaming/video/ffmpeg-renderers/pacer/pacer.cpp

@@ -65,6 +65,12 @@ int Pacer::renderThread(void* context)
 {
     Pacer* me = reinterpret_cast<Pacer*>(context);
 
+    if (SDL_SetThreadPriority(SDL_THREAD_PRIORITY_HIGH) < 0) {
+        SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
+                    "Unable to set render thread to high priority: %s",
+                    SDL_GetError());
+    }
+
     while (!me->m_Stopping) {
         // Acquire the frame queue lock to protect the queue and
         // the not empty condition