shithub: libvpx

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Merge "vp8-denoiser: Use the same skin detection for model=1 as in vp9."

--- a/vp8/encoder/pickinter.c

+++ b/vp8/encoder/pickinter.c

@@ -50,7 +50,8 @@

 static const int skin_mean[5][2] =

     {{7463, 9614}, {6400, 10240}, {7040, 10240}, {8320, 9280}, {6800, 9614}};

 static const int skin_inv_cov[4] = {4107, 1663, 1663, 2157};  // q16

-static const int skin_threshold[2] = {1570636, 800000};       // q18

+static const int skin_threshold[6] = {1570636, 1400000, 800000, 800000, 800000,

+    800000};  // q18

 // Evaluates the Mahalanobis distance measure for the input CbCr values.

 static int evaluate_skin_color_difference(int cb, int cr, int idx) {

@@ -73,7 +74,7 @@

 }

 // Checks if the input yCbCr values corresponds to skin color.

-static int is_skin_color(int y, int cb, int cr)

+static int is_skin_color(int y, int cb, int cr, int consec_zeromv)

 {

   if (y < 40 || y > 220)

   {

@@ -88,13 +89,31 @@

     else

     {

       int i = 0;

-      for (; i < 5; i++)

-      {

-        if (evaluate_skin_color_difference(cb, cr, i) < skin_threshold[1])

-        {

-          return 1;

-        }

-      }

+      // No skin if block has been zero motion for long consecutive time.

+      if (consec_zeromv > 80)

+        return 0;

+      // Exit on grey.

+       if (cb == 128 && cr == 128)

+         return 0;

+       // Exit on very strong cb.

+       if (cb > 150 && cr < 110)

+         return 0;

+       for (; i < 5; i++) {

+         int skin_color_diff = evaluate_skin_color_difference(cb, cr, i);

+         if (skin_color_diff < skin_threshold[i + 1]) {

+            if (y < 60 && skin_color_diff > 3 * (skin_threshold[i + 1] >> 2))

+              return 0;

+            else if (consec_zeromv > 30 &&

+                     skin_color_diff > (skin_threshold[i + 1] >> 1))

+              return 0;

+            else

+             return 1;

+         }

+         // Exit if difference is much large than the threshold.

+         if (skin_color_diff > (skin_threshold[i + 1] << 3)) {

+           return 0;

+         }

+       }

       return 0;

     }

   }

@@ -851,8 +870,10 @@

         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 (!cpi->oxcf.screen_content_mode) {

+      int block_index = mb_row * cpi->common.mb_cols + mb_col;

+      x->is_skin = is_skin_color(y, cb, cr, cpi->consec_zero_last[block_index]);

+    }

     }

 #if CONFIG_TEMPORAL_DENOISING

     if (cpi->oxcf.noise_sensitivity) {