Ignore unmoved moved_rects in DxgiOutputDuplicator

webrtc/modules/desktop_capture/win/dxgi_output_duplicator.cc

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 270 matching lines @@
       static_cast<UINT>(metadata_.capacity()) - buff_size, dirty_rects,
       &buff_size);
   if (error.Error() != S_OK) {
     LOG(LS_ERROR) << "Failed to get dirty rectangles, error "
                   << error.ErrorMessage() << ", code " << error.Error();
     return false;
   }
   dirty_rects_count = buff_size / sizeof(RECT);
 
   while (move_rects_count > 0) {
-    updated_region->AddRect(
-        RotateRect(DesktopRect::MakeXYWH(move_rects->SourcePoint.x,
-                                         move_rects->SourcePoint.y,
-                                         move_rects->DestinationRect.right -
-                                             move_rects->DestinationRect.left,
-                                         move_rects->DestinationRect.bottom -
-                                             move_rects->DestinationRect.top),
-                   unrotated_size_, rotation_));
-    updated_region->AddRect(
-        RotateRect(DesktopRect::MakeLTRB(move_rects->DestinationRect.left,
-                                         move_rects->DestinationRect.top,
-                                         move_rects->DestinationRect.right,
-                                         move_rects->DestinationRect.bottom),
-                   unrotated_size_, rotation_));
+    // DirectX capturer API may randomly return unmoved move_rects, which should
+    // be skipped to avoid unnecessary wasting of differing and encoding
+    // resources.
+    // By using testing application it2me_standalone_host_main, this check
+    // reduces average capture time by 0.375% (4.07 -> 4.055), and average
+    // encode time by 0.313% (8.042 -> 8.016) without other impacts.
+    if (move_rects->SourcePoint.x != move_rects->DestinationRect.left ||
+        move_rects->SourcePoint.y != move_rects->DestinationRect.top) {
+      updated_region->AddRect(
+          RotateRect(DesktopRect::MakeXYWH(move_rects->SourcePoint.x,
+                                           move_rects->SourcePoint.y,
+                                           move_rects->DestinationRect.right -
+                                               move_rects->DestinationRect.left,
+                                           move_rects->DestinationRect.bottom -
+                                               move_rects->DestinationRect.top),
+                     unrotated_size_, rotation_));
+      updated_region->AddRect(
+          RotateRect(DesktopRect::MakeLTRB(move_rects->DestinationRect.left,
+                                           move_rects->DestinationRect.top,
+                                           move_rects->DestinationRect.right,
+                                           move_rects->DestinationRect.bottom),
+                     unrotated_size_, rotation_));
+    } else {
+      LOG(LS_INFO) << "Unmoved move_rect detected, ["
+                   << move_rects->DestinationRect.left << ", "
+                   << move_rects->DestinationRect.top << "] - ["
+                   << move_rects->DestinationRect.right << ", "
+                   << move_rects->DestinationRect.bottom << "].";
+    }
     move_rects++;
     move_rects_count--;
   }
 
   while (dirty_rects_count > 0) {
     updated_region->AddRect(RotateRect(
         DesktopRect::MakeLTRB(dirty_rects->left, dirty_rects->top,
                               dirty_rects->right, dirty_rects->bottom),
         unrotated_size_, rotation_));
     dirty_rects++;
@@ skipping 28 matching lines @@
 }
 
 int64_t DxgiOutputDuplicator::num_frames_captured() const {
 #if !defined(NDEBUG)
   RTC_DCHECK_EQ(!!last_frame_, num_frames_captured_ > 0);
 #endif
   return num_frames_captured_;
 }
 
 }  // namespace webrtc