shithub: libvpx

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Merge "Non-rd variance partition: Adjustments to reduce dragging artifact."

--- a/vp9/encoder/vp9_encodeframe.c

+++ b/vp9/encoder/vp9_encodeframe.c

@@ -496,6 +496,8 @@

         threshold_base = 3 * threshold_base;

       else if (noise_level == kMedium)

         threshold_base = threshold_base << 1;

+      else if (noise_level < kLow)

+        threshold_base = (7 * threshold_base) >> 3;

     }

     if (cm->width <= 352 && cm->height <= 288) {

       thresholds[0] = threshold_base >> 3;

@@ -668,6 +670,8 @@

   v64x64 vt;

   v16x16 vt2[16];

   int force_split[21];

+  int avg_32x32;

+  int avg_16x16[4];

   uint8_t *s;

   const uint8_t *d;

   int sp;

@@ -819,6 +823,7 @@

     const int y32_idx = ((i >> 1) << 5);

     const int i2 = i << 2;

     force_split[i + 1] = 0;

+    avg_16x16[i] = 0;

     for (j = 0; j < 4; j++) {

       const int x16_idx = x32_idx + ((j & 1) << 4);

       const int y16_idx = y32_idx + ((j >> 1) << 4);

@@ -836,6 +841,7 @@

                             is_key_frame);

         fill_variance_tree(&vt.split[i].split[j], BLOCK_16X16);

         get_variance(&vt.split[i].split[j].part_variances.none);

+        avg_16x16[i] += vt.split[i].split[j].part_variances.none.variance;

         if (vt.split[i].split[j].part_variances.none.variance >

             thresholds[2]) {

           // 16X16 variance is above threshold for split, so force split to 8x8

@@ -888,6 +894,7 @@

   }

   // Fill the rest of the variance tree by summing split partition values.

+  avg_32x32 = 0;

   for (i = 0; i < 4; i++) {

     const int i2 = i << 2;

     for (j = 0; j < 4; j++) {

@@ -908,19 +915,29 @@

       }

     }

     fill_variance_tree(&vt.split[i], BLOCK_32X32);

-    // If variance of this 32x32 block is above the threshold, force the block

-    // to split. This also forces a split on the upper (64x64) level.

+    // If variance of this 32x32 block is above the threshold, or if its above

+    // (some threshold of) the average variance over the sub-16x16 blocks, then

+    // force this block to split. This also forces a split on the upper

+    // (64x64) level.

     if (!force_split[i + 1]) {

       get_variance(&vt.split[i].part_variances.none);

-      if (vt.split[i].part_variances.none.variance > thresholds[1]) {

+      if (vt.split[i].part_variances.none.variance > thresholds[1] ||

+          (!is_key_frame &&

+          vt.split[i].part_variances.none.variance > (3 * avg_16x16[i]) >> 2)) {

         force_split[i + 1] = 1;

         force_split[0] = 1;

       }

+      avg_32x32 += vt.split[i].part_variances.none.variance;

     }

   }

   if (!force_split[0]) {

     fill_variance_tree(&vt, BLOCK_64X64);

     get_variance(&vt.part_variances.none);

+    // If variance of this 64x64 block is above (some threshold of) the average

+    // variance over the sub-32x32 blocks, then force this block to split.

+    if (!is_key_frame &&

+        vt.part_variances.none.variance > (3 * avg_32x32) >> 3)

+      force_split[0] = 1;

   }

   // Now go through the entire structure, splitting every block size until