diff --git a/media/gpu/windows/media_foundation_video_encode_accelerator_win.cc b/media/gpu/windows/media_foundation_video_encode_accelerator_win.cc
index 0000000000..1111111111 100644
--- a/media/gpu/windows/media_foundation_video_encode_accelerator_win.cc
+++ b/media/gpu/windows/media_foundation_video_encode_accelerator_win.cc
@@ -3111,6 +3111,18 @@ HRESULT MediaFoundationVideoEncodeAccelerator::PerformD3DCopy(
     D3D11_TEXTURE2D_DESC input_desc;
     input_texture->GetDesc(&input_desc);

+    // The destination texture (`copied_d3d11_texture_`) is hardcoded to
+    // DXGI_FORMAT_NV12 in InitializeD3DCopying(). CopySubresourceRegion
+    // requires source and destination formats to be in the same type group;
+    // if they are not, the D3D11 runtime silently drops the copy, leaving
+    // the destination filled with uninitialized GPU memory which would then
+    // be encoded and returned to the caller.
+    if (input_desc.Format != DXGI_FORMAT_NV12) {
+      LOG(ERROR) << "Source texture format " << input_desc.Format
+                 << " is incompatible with NV12 destination";
+      return E_INVALIDARG;
+    }
+
     if (visible_rect.x() < 0 || visible_rect.y() < 0 ||
         visible_rect.right() > static_cast<int>(input_desc.Width) ||
         visible_rect.bottom() > static_cast<int>(input_desc.Height)) {