shithub: libvpx

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VP9 noise estimation: add frame level motion metrics and adjust thresholds.

Change-Id: Ia1aba00603b32cee6835951d3d8f740937cf20f4

--- a/vp9/encoder/vp9_noise_estimate.c

+++ b/vp9/encoder/vp9_noise_estimate.c

@@ -88,7 +88,7 @@

   // Estimate of noise level every frame_period frames.

   int frame_period = 10;

   int thresh_consec_zeromv = 8;

-  unsigned int thresh_sum_diff = 128;

+  unsigned int thresh_sum_diff = 100;

   unsigned int thresh_sum_spatial = (200 * 200) << 8;

   unsigned int thresh_spatial_var = (32 * 32) << 8;

   int num_frames_estimate = 20;

@@ -135,8 +135,19 @@

     const int uv_width_shift = y_width_shift >> 1;

     const int uv_height_shift = y_height_shift >> 1;

     int mi_row, mi_col;

+    int num_low_motion = 0;

+    int frame_low_motion = 1;

     for (mi_row = 0; mi_row < cm->mi_rows; mi_row++) {

       for (mi_col = 0; mi_col < cm->mi_cols; mi_col++) {

+        int bl_index = mi_row * cm->mi_cols + mi_col;

+        if (cr->consec_zero_mv[bl_index] > thresh_consec_zeromv)

+          num_low_motion++;

+      }

+    }

+    if (num_low_motion < ((3 * cm->mi_rows * cm->mi_cols) >> 3))

+      frame_low_motion = 0;

+    for (mi_row = 0; mi_row < cm->mi_rows; mi_row++) {

+      for (mi_col = 0; mi_col < cm->mi_cols; mi_col++) {

         // 16x16 blocks, 1/4 sample of frame.

         if (mi_row % 4 == 0 && mi_col % 4 == 0) {

           int bl_index = mi_row * cm->mi_cols + mi_col;

@@ -154,7 +165,8 @@

           const uint8_t vsource =

             src_v[uv_height_shift * src_uvstride + uv_width_shift];

           int is_skin = vp9_skin_pixel(ysource, usource, vsource);

-          if (cr->consec_zero_mv[bl_index] > thresh_consec_zeromv &&

+          if (frame_low_motion &&

+              cr->consec_zero_mv[bl_index] > thresh_consec_zeromv &&

               cr->consec_zero_mv[bl_index1] > thresh_consec_zeromv &&

               cr->consec_zero_mv[bl_index2] > thresh_consec_zeromv &&

               cr->consec_zero_mv[bl_index3] > thresh_consec_zeromv &&

@@ -202,10 +214,11 @@

       // Normalize.

       avg_est = avg_est / num_samples;

       // Update noise estimate.

-      ne->value = (int)((3 * ne->value + avg_est) >> 2);

+      ne->value = (int)((15 * ne->value + avg_est) >> 4);

       ne->count++;

       if (ne->count == num_frames_estimate) {

         // Reset counter and check noise level condition.

+        num_frames_estimate = 40;

         ne->count = 0;

         if (ne->value > (ne->thresh << 1))

           ne->level = kHigh;