shithub: libvpx

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Add normalization over frame level Wiener variance

Normalize the block level Wiener variance based decision according
to the frame level Wiener variance.

Change-Id: Ic2bdf1b322a65661775541dd6c174ba71579461a

--- a/vp9/encoder/vp9_encoder.c

+++ b/vp9/encoder/vp9_encoder.c

@@ -4732,7 +4732,7 @@

   DECLARE_ALIGNED(16, int16_t, src_diff[32 * 32]);

   DECLARE_ALIGNED(16, tran_low_t, coeff[32 * 32]);

-  int mb_row, mb_col;

+  int mb_row, mb_col, count = 0;

   // Hard coded operating block size

   const int block_size = 16;

   const int coeff_count = block_size * block_size;

@@ -4749,6 +4749,8 @@

   memset(zero_pred, 0, sizeof(*zero_pred) * coeff_count);

+  cpi->norm_wiener_variance = 0;

+

   for (mb_row = 0; mb_row < cm->mb_rows; ++mb_row) {

     for (mb_col = 0; mb_col < cm->mb_cols; ++mb_col) {

       int idx, hist_count = 0;

@@ -4789,18 +4791,21 @@

       // Wiener filter

       for (idx = 1; idx < coeff_count; ++idx) {

-        int sign = coeff[idx] < 0;

         int64_t sqr_coeff = (int64_t)coeff[idx] * coeff[idx];

         coeff[idx] = (int16_t)((sqr_coeff * coeff[idx]) /

                                (sqr_coeff + (int64_t)median_val * median_val));

-        if (sign) coeff[idx] = -coeff[idx];

-

         wiener_variance += (int64_t)coeff[idx] * coeff[idx];

       }

       cpi->mb_wiener_variance[mb_row * cm->mb_cols + mb_col] =

           wiener_variance / coeff_count;

+      cpi->norm_wiener_variance +=

+          cpi->mb_wiener_variance[mb_row * cm->mb_cols + mb_col];

+      ++count;

     }

   }

+

+  if (count) cpi->norm_wiener_variance /= count;

+  cpi->norm_wiener_variance = VPXMAX(1, cpi->norm_wiener_variance);

 }

 static void encode_frame_to_data_rate(VP9_COMP *cpi, size_t *size,

--- a/vp9/encoder/vp9_encoder.h

+++ b/vp9/encoder/vp9_encoder.h

@@ -628,6 +628,7 @@

   int ext_refresh_frame_context_pending;

   int ext_refresh_frame_context;

+  int64_t norm_wiener_variance;

   int64_t *mb_wiener_variance;

   int *stack_rank_buffer;