libvpx: Pull from upstream

source/libvpx/vp8/encoder/denoising.c

Index: source/libvpx/vp8/encoder/denoising.c
===================================================================
--- source/libvpx/vp8/encoder/denoising.c	(revision 281795)
+++ source/libvpx/vp8/encoder/denoising.c	(working copy)
@@ -191,6 +191,148 @@
     return FILTER_BLOCK;
 }
 
+int vp8_denoiser_filter_uv_c(unsigned char *mc_running_avg_uv,
+                             int mc_avg_uv_stride,
+                             unsigned char *running_avg_uv,
+                             int avg_uv_stride,
+                             unsigned char *sig,
+                             int sig_stride,
+                             unsigned int motion_magnitude,
+                             int increase_denoising) {
+    unsigned char *running_avg_uv_start = running_avg_uv;
+    unsigned char *sig_start = sig;
+    int sum_diff_thresh;
+    int r, c;
+    int sum_diff = 0;
+    int sum_block = 0;
+    int adj_val[3] = {3, 4, 6};
+    int shift_inc1 = 0;
+    int shift_inc2 = 1;
+    /* If motion_magnitude is small, making the denoiser more aggressive by
+     * increasing the adjustment for each level. Add another increment for
+     * blocks that are labeled for increase denoising. */
+    if (motion_magnitude <= MOTION_MAGNITUDE_THRESHOLD_UV) {
+      if (increase_denoising) {
+        shift_inc1 = 1;
+        shift_inc2 = 2;
+      }
+      adj_val[0] += shift_inc2;
+      adj_val[1] += shift_inc2;
+      adj_val[2] += shift_inc2;
+    }
+
+    // Avoid denoising color signal if its close to average level.
+    for (r = 0; r < 8; ++r) {
+      for (c = 0; c < 8; ++c) {
+        sum_block += sig[c];
+      }
+      sig += sig_stride;
+    }
+    if (abs(sum_block - (128 * 8 * 8)) < SUM_DIFF_FROM_AVG_THRESH_UV) {
+      return COPY_BLOCK;
+    }
+
+    sig -= sig_stride * 8;
+    for (r = 0; r < 8; ++r) {
+      for (c = 0; c < 8; ++c) {
+        int diff = 0;
+        int adjustment = 0;
+        int absdiff = 0;
+
+        diff = mc_running_avg_uv[c] - sig[c];
+        absdiff = abs(diff);
+
+        // When |diff| <= |3 + shift_inc1|, use pixel value from
+        // last denoised raw.
+        if (absdiff <= 3 + shift_inc1) {
+          running_avg_uv[c] = mc_running_avg_uv[c];
+          sum_diff += diff;
+        } else {
+          if (absdiff >= 4 && absdiff <= 7)
+            adjustment = adj_val[0];
+          else if (absdiff >= 8 && absdiff <= 15)
+            adjustment = adj_val[1];
+          else
+            adjustment = adj_val[2];
+          if (diff > 0) {
+            if ((sig[c] + adjustment) > 255)
+              running_avg_uv[c] = 255;
+            else
+              running_avg_uv[c] = sig[c] + adjustment;
+            sum_diff += adjustment;
+          } else {
+            if ((sig[c] - adjustment) < 0)
+              running_avg_uv[c] = 0;
+            else
+              running_avg_uv[c] = sig[c] - adjustment;
+            sum_diff -= adjustment;
+          }
+        }
+      }
+      /* Update pointers for next iteration. */
+      sig += sig_stride;
+      mc_running_avg_uv += mc_avg_uv_stride;
+      running_avg_uv += avg_uv_stride;
+    }
+
+    sum_diff_thresh= SUM_DIFF_THRESHOLD_UV;
+    if (increase_denoising) sum_diff_thresh = SUM_DIFF_THRESHOLD_HIGH_UV;
+    if (abs(sum_diff) > sum_diff_thresh) {
+      // Before returning to copy the block (i.e., apply no denoising), check
+      // if we can still apply some (weaker) temporal filtering to this block,
+      // that would otherwise not be denoised at all. Simplest is to apply
+      // an additional adjustment to running_avg_y to bring it closer to sig.
+      // The adjustment is capped by a maximum delta, and chosen such that
+      // in most cases the resulting sum_diff will be within the
+      // accceptable range given by sum_diff_thresh.
+
+      // The delta is set by the excess of absolute pixel diff over threshold.
+      int delta = ((abs(sum_diff) - sum_diff_thresh) >> 8) + 1;
+      // Only apply the adjustment for max delta up to 3.
+      if (delta < 4) {
+        sig -= sig_stride * 8;
+        mc_running_avg_uv -= mc_avg_uv_stride * 8;
+        running_avg_uv -= avg_uv_stride * 8;
+        for (r = 0; r < 8; ++r) {
+          for (c = 0; c < 8; ++c) {
+            int diff = mc_running_avg_uv[c] - sig[c];
+            int adjustment = abs(diff);
+            if (adjustment > delta)
+              adjustment = delta;
+            if (diff > 0) {
+              // Bring denoised signal down.
+              if (running_avg_uv[c] - adjustment < 0)
+                running_avg_uv[c] = 0;
+              else
+                running_avg_uv[c] = running_avg_uv[c] - adjustment;
+              sum_diff -= adjustment;
+            } else if (diff < 0) {
+              // Bring denoised signal up.
+              if (running_avg_uv[c] + adjustment > 255)
+                running_avg_uv[c] = 255;
+              else
+                running_avg_uv[c] = running_avg_uv[c] + adjustment;
+              sum_diff += adjustment;
+            }
+          }
+          // TODO(marpan): Check here if abs(sum_diff) has gone below the
+          // threshold sum_diff_thresh, and if so, we can exit the row loop.
+          sig += sig_stride;
+          mc_running_avg_uv += mc_avg_uv_stride;
+          running_avg_uv += avg_uv_stride;
+        }
+        if (abs(sum_diff) > sum_diff_thresh)
+          return COPY_BLOCK;
+      } else {
+        return COPY_BLOCK;
+      }
+    }
+
+    vp8_copy_mem8x8(running_avg_uv_start, avg_uv_stride, sig_start,
+                    sig_stride);
+    return FILTER_BLOCK;
+}
+
 int vp8_denoiser_allocate(VP8_DENOISER *denoiser, int width, int height,
                           int num_mb_rows, int num_mb_cols)
 {
@@ -261,6 +403,8 @@
     unsigned int motion_magnitude2;
     unsigned int sse_thresh;
     int sse_diff_thresh = 0;
+    // Denoise the UV channel.
+    int apply_color_denoise = 0;
     // Spatial loop filter: only applied selectively based on
     // temporal filter state of block relative to top/left neighbors.
     int apply_spatial_loop_filter = 1;
@@ -268,6 +412,8 @@
     MV_REFERENCE_FRAME zero_frame = x->best_zeromv_reference_frame;
 
     enum vp8_denoiser_decision decision = FILTER_BLOCK;
+    enum vp8_denoiser_decision decision_u = FILTER_BLOCK;
+    enum vp8_denoiser_decision decision_v = FILTER_BLOCK;
 
     if (zero_frame)
     {
@@ -377,11 +523,37 @@
 
         /* Filter. */
         decision = vp8_denoiser_filter(mc_running_avg_y, mc_avg_y_stride,
-                                         running_avg_y, avg_y_stride,
-                                         x->thismb, 16, motion_magnitude2,
-                                         x->increase_denoising);
+                                       running_avg_y, avg_y_stride,
+                                       x->thismb, 16, motion_magnitude2,
+                                       x->increase_denoising);
         denoiser->denoise_state[block_index] = motion_magnitude2 > 0 ?
             kFilterNonZeroMV : kFilterZeroMV;
+        // Only denoise UV for zero motion, and if y channel was denoised.
+        if (apply_color_denoise &&
+            motion_magnitude2 == 0 &&
+            decision == FILTER_BLOCK) {
+          unsigned char *mc_running_avg_u =
+              denoiser->yv12_mc_running_avg.u_buffer + recon_uvoffset;
+          unsigned char *running_avg_u =
+              denoiser->yv12_running_avg[INTRA_FRAME].u_buffer + recon_uvoffset;
+          unsigned char *mc_running_avg_v =
+              denoiser->yv12_mc_running_avg.v_buffer + recon_uvoffset;
+          unsigned char *running_avg_v =
+              denoiser->yv12_running_avg[INTRA_FRAME].v_buffer + recon_uvoffset;
+          int mc_avg_uv_stride = denoiser->yv12_mc_running_avg.uv_stride;
+          int avg_uv_stride = denoiser->yv12_running_avg[INTRA_FRAME].uv_stride;
+          int signal_stride = x->block[16].src_stride;
+          decision_u =
+              vp8_denoiser_filter_uv(mc_running_avg_u, mc_avg_uv_stride,
+                                      running_avg_u, avg_uv_stride,
+                                      x->block[16].src + *x->block[16].base_src,
+                                      signal_stride, motion_magnitude2, 0);
+          decision_v =
+              vp8_denoiser_filter_uv(mc_running_avg_v, mc_avg_uv_stride,
+                                      running_avg_v, avg_uv_stride,
+                                      x->block[20].src + *x->block[20].base_src,
+                                      signal_stride, motion_magnitude2, 0);
+        }
     }
     if (decision == COPY_BLOCK)
     {
@@ -394,7 +566,21 @@
                 denoiser->yv12_running_avg[INTRA_FRAME].y_stride);
         denoiser->denoise_state[block_index] = kNoFilter;
     }
-    // Option to selectively deblock the denoised signal.
+    if (apply_color_denoise) {
+      if (decision_u == COPY_BLOCK) {
+        vp8_copy_mem8x8(
+            x->block[16].src + *x->block[16].base_src, x->block[16].src_stride,
+            denoiser->yv12_running_avg[INTRA_FRAME].u_buffer + recon_uvoffset,
+            denoiser->yv12_running_avg[INTRA_FRAME].uv_stride);
+      }
+      if (decision_v == COPY_BLOCK) {
+        vp8_copy_mem8x8(
+            x->block[20].src + *x->block[20].base_src, x->block[16].src_stride,
+            denoiser->yv12_running_avg[INTRA_FRAME].v_buffer + recon_uvoffset,
+            denoiser->yv12_running_avg[INTRA_FRAME].uv_stride);
+      }
+    }
+    // Option to selectively deblock the denoised signal, for y channel only.
     if (apply_spatial_loop_filter) {
       loop_filter_info lfi;
       int apply_filter_col = 0;