Pause frame processing when window is not active

src/io_pipeline.c

@@ -2,6 +2,7 @@
 
 #include "camera.h"
 #include "flash.h"
+#include "main.h"
 #include "pipeline.h"
 #include "process_pipeline.h"
 #include "state.h"
@@ -240,6 +241,11 @@ update_controls()
 static void
 on_frame(MPBuffer buffer, void *_data)
 {
+        // Don't process frame when the window is not active
+        if (!check_window_active()) {
+                return;
+        }
+        
         // Only update controls right after a frame was captured
         update_controls();