libvpx: Pull from upstream

source/libvpx/vp8/encoder/pickinter.c

 /*
  *  Copyright (c) 2010 The WebM 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 795 matching lines @@
 
         // Don't do mv reuse since we want to allow for another mode besides
         // ZEROMV_LAST to remove dot artifact.
         if (dot_artifact_candidate)
           parent_ref_valid = 0;
     }
 #endif
 
     // Check if current macroblock is in skin area.
     {
-    const int y = x->src.y_buffer[7 * x->src.y_stride + 7];
-    const int cb = x->src.u_buffer[3 * x->src.uv_stride + 3];
-    const int cr = x->src.v_buffer[3 * x->src.uv_stride + 3];
+    const int y = (x->src.y_buffer[7 * x->src.y_stride + 7] +
+        x->src.y_buffer[7 * x->src.y_stride + 8] +
+        x->src.y_buffer[8 * x->src.y_stride + 7] +
+        x->src.y_buffer[8 * x->src.y_stride + 8]) >> 2;
+    const int cb = (x->src.u_buffer[3 * x->src.uv_stride + 3] +
+        x->src.u_buffer[3 * x->src.uv_stride + 4] +
+        x->src.u_buffer[4 * x->src.uv_stride + 3] +
+        x->src.u_buffer[4 * x->src.uv_stride + 4]) >> 2;
+    const int cr = (x->src.v_buffer[3 * x->src.uv_stride + 3] +
+        x->src.v_buffer[3 * x->src.uv_stride + 4] +
+        x->src.v_buffer[4 * x->src.uv_stride + 3] +
+        x->src.v_buffer[4 * x->src.uv_stride + 4]) >> 2;
     x->is_skin = 0;
     if (!cpi->oxcf.screen_content_mode)
       x->is_skin = is_skin_color(y, cb, cr);
     }
 #if CONFIG_TEMPORAL_DENOISING
     if (cpi->oxcf.noise_sensitivity) {
       // Under aggressive denoising mode, should we use skin map to reduce denoiser
       // and ZEROMV bias? Will need to revisit the accuracy of this detection for
       // very noisy input. For now keep this as is (i.e., don't turn it off). 
       // if (cpi->denoiser.denoiser_mode == kDenoiserOnYUVAggressive)
@@ skipping 713 matching lines @@
     error4x4 = pick_intra4x4mby_modes(x, &rate,
                                       &best_sse);
     if (error4x4 < error16x16)
     {
         xd->mode_info_context->mbmi.mode = B_PRED;
         best_rate = rate;
     }
 
     *rate_ = best_rate;
 }