media/gpu/vea_perf_tests: Change the way of computing the bitrate dev…

…iation

This CL changes the way of computing the bitrate deviation for
temporal layer encoding. It compares with the sums of bitrates of
the temporal layers in the same spatial layer. The value represents
more clearly the bitrate deviation of streams received by a decoder.

Bug: b:220225711
Test: video_encode_accelerator_perf_tests
Change-Id: I1ae86eb448e737d3bb6d8f57f21166982f9c092f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3583588
Reviewed-by: Miguel Casas-Sanchez <mcasas@chromium.org>
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Cr-Commit-Position: refs/heads/main@{#992455}

media/gpu/video_encode_accelerator_perf_tests.cc

@@ -419,7 +419,8 @@ void BitstreamQualityMetrics::WriteToConsole(
     uint32_t actual_bitrate) const {
   const auto default_ssize = std::cout.precision();
   std::cout << "[ Result " << svc_text << "]" << std::endl;
-  std::cout << "Bitrate: " << actual_bitrate << std::endl;
+  std::cout << "Bitrate: " << actual_bitrate << " (target:  " << target_bitrate
+            << ")" << std::endl;
   std::cout << "Bitrate deviation: " << std::fixed << std::setprecision(2)
             << (actual_bitrate * 100.0 / target_bitrate) - 100.0 << " %"
             << std::endl;
@@ -459,7 +460,7 @@ void BitstreamQualityMetrics::WriteToFile(
   metrics.SetKey("Bitrate",
                  base::Value(base::checked_cast<int>(actual_bitrate)));
   metrics.SetKey(
-      "Bitrate deviation",
+      "BitrateDeviation",
       base::Value((actual_bitrate * 100.0 / target_bitrate) - 100.0));
   metrics.SetKey("SSIMAverage", base::Value(ssim_stats.avg));
   metrics.SetKey("PSNRAverage", base::Value(psnr_stats.avg));
@@ -709,9 +710,12 @@ TEST_F(VideoEncoderTest, MeasureProducedBitstreamQuality) {
       actual_bitrate = stats.Bitrate();
     } else {
       CHECK(spatial_idx && temporal_idx);
-      target_bitrate =
-          g_env->Bitrate().GetBitrateBps(*spatial_idx, *temporal_idx);
-      actual_bitrate = stats.LayerBitrate(*spatial_idx, *temporal_idx);
+      // Target and actual bitrates in temporal layer encoding are the sum of
+      // bitrates of the temporal layers in the spatial layer.
+      for (size_t tid = 0; tid <= *temporal_idx; ++tid) {
+        target_bitrate += g_env->Bitrate().GetBitrateBps(*spatial_idx, tid);
+        actual_bitrate += stats.LayerBitrate(*spatial_idx, tid);
+      }
     }
 
     metrics.Output(target_bitrate, actual_bitrate);