diff --git a/modules/desktop_capture/win/dxgi_output_duplicator.cc b/modules/desktop_capture/win/dxgi_output_duplicator.cc
index c90e2f1ab5..65a0d77667 100644
--- a/modules/desktop_capture/win/dxgi_output_duplicator.cc
+++ b/modules/desktop_capture/win/dxgi_output_duplicator.cc
@@ -271,7 +271,7 @@ bool DxgiOutputDuplicator::DoDetectUpdatedRegion(
     return false;
   }
 
-  if (metadata_.capacity() < frame_info.TotalMetadataBufferSize) {
+  if (metadata_.size() < frame_info.TotalMetadataBufferSize) {
     metadata_.clear();  // Avoid data copy
     metadata_.resize(frame_info.TotalMetadataBufferSize);
   }
@@ -281,7 +281,7 @@ bool DxgiOutputDuplicator::DoDetectUpdatedRegion(
       reinterpret_cast<DXGI_OUTDUPL_MOVE_RECT*>(metadata_.data());
   size_t move_rects_count = 0;
   _com_error error = duplication_->GetFrameMoveRects(
-      static_cast<UINT>(metadata_.capacity()), move_rects, &buff_size);
+      static_cast<UINT>(metadata_.size()), move_rects, &buff_size);
   if (error.Error() != S_OK) {
     RTC_LOG(LS_ERROR) << "Failed to get move rectangles: "
                       << desktop_capture::utils::ComErrorToString(error);
@@ -292,8 +292,7 @@ bool DxgiOutputDuplicator::DoDetectUpdatedRegion(
   RECT* dirty_rects = reinterpret_cast<RECT*>(metadata_.data() + buff_size);
   size_t dirty_rects_count = 0;
   error = duplication_->GetFrameDirtyRects(
-      static_cast<UINT>(metadata_.capacity()) - buff_size, dirty_rects,
-      &buff_size);
+      static_cast<UINT>(metadata_.size()) - buff_size, dirty_rects, &buff_size);
   if (error.Error() != S_OK) {
     RTC_LOG(LS_ERROR) << "Failed to get dirty rectangles: "
                       << desktop_capture::utils::ComErrorToString(error);