Disable VP8 hardware decoding below 480p.

Per meet statistics, it's actually more expensive than software
decoding.

R=liberato

Bug: 1136495
Change-Id: I56e7e459c53b38a0fa65b8a7606e28ed27dcc300
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2463964Reviewed-by: Frank Liberato <liberato@chromium.org>
Commit-Queue: Frank Liberato <liberato@chromium.org>
Auto-Submit: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#815848}

media/gpu/windows/supported_profile_helpers.cc

@@ -163,7 +163,8 @@ media::SupportedResolutionRange GetResolutionsForGUID(
     ID3D11VideoDevice* video_device,
     const GUID& decoder_guid,
     const std::vector<gfx::Size>& resolutions_to_test,
-    DXGI_FORMAT format = DXGI_FORMAT_NV12) {
+    DXGI_FORMAT format = DXGI_FORMAT_NV12,
+    const gfx::Size& min_resolution = kMinResolution) {
   media::SupportedResolutionRange result;
 
   // Verify input is in ascending order by height.
@@ -191,7 +192,7 @@ media::SupportedResolutionRange GetResolutionsForGUID(
   }
 
   if (!result.max_landscape_resolution.IsEmpty())
-    result.min_resolution = kMinResolution;
+    result.min_resolution = min_resolution;
 
   return result;
 }
@@ -299,10 +300,15 @@ SupportedResolutionRangeMap GetSupportedD3D11VideoDecoderResolutions(
     if (!workarounds.disable_accelerated_vp8_decode &&
         profile_id == D3D11_DECODER_PROFILE_VP8_VLD &&
         base::FeatureList::IsEnabled(kMediaFoundationVP8Decoding)) {
-      supported_resolutions[VP8PROFILE_ANY] =
-          GetResolutionsForGUID(video_device.Get(), profile_id,
-                                {gfx::Size(4096, 2160), gfx::Size(4096, 2304),
-                                 gfx::Size(4096, 4096)});
+      // VP8 decoding is cheap on modern devices compared to other codecs, so
+      // much so that hardware decoding performance is actually worse at low
+      // resolutions than software decoding. See https://crbug.com/1136495.
+      constexpr gfx::Size kMinVp8Resolution = gfx::Size(640, 480);
+
+      supported_resolutions[VP8PROFILE_ANY] = GetResolutionsForGUID(
+          video_device.Get(), profile_id,
+          {gfx::Size(4096, 2160), gfx::Size(4096, 2304), gfx::Size(4096, 4096)},
+          DXGI_FORMAT_NV12, kMinVp8Resolution);
       continue;
     }
 

media/gpu/windows/supported_profile_helpers_unittest.cc

@@ -219,7 +219,19 @@ TEST_F(SupportedResolutionResolverTest, VP8Supports4k) {
 
   base::test::ScopedFeatureList scoped_feature_list;
   scoped_feature_list.InitAndEnableFeature(kMediaFoundationVP8Decoding);
-  TestDecoderSupport(D3D11_DECODER_PROFILE_VP8_VLD, VP8PROFILE_ANY);
+
+  EnableDecoders({D3D11_DECODER_PROFILE_VP8_VLD});
+  SetMaxResolution(D3D11_DECODER_PROFILE_VP8_VLD, kSquare4k);
+
+  const auto supported_resolutions = GetSupportedD3D11VideoDecoderResolutions(
+      mock_d3d11_device_, gpu_workarounds_);
+  auto it = supported_resolutions.find(VP8PROFILE_ANY);
+  ASSERT_NE(it, supported_resolutions.end());
+  EXPECT_EQ(kSquare4k, it->second.max_landscape_resolution);
+  EXPECT_EQ(kSquare4k, it->second.max_portrait_resolution);
+
+  constexpr gfx::Size kMinVp8Resolution = gfx::Size(640, 480);
+  EXPECT_EQ(kMinVp8Resolution, it->second.min_resolution);
 }
 
 TEST_F(SupportedResolutionResolverTest, VP9Profile0Supports8k) {