libvpx: Pull from upstream

source/libvpx/vp9/encoder/vp9_skin_detection.c

 /*
  *  Copyright (c) 2015 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 33 matching lines @@
 int vp9_skin_pixel(const uint8_t y, const uint8_t cb, const uint8_t cr) {
   if (y < y_low || y > y_high)
     return 0;
   else
     return (evaluate_skin_color_difference(cb, cr) < skin_threshold);
 }
 
 #ifdef OUTPUT_YUV_SKINMAP
 // For viewing skin map on input source.
 void vp9_compute_skin_map(VP9_COMP *const cpi, FILE *yuv_skinmap_file) {
-  int i, j, mi_row, mi_col;
+  int i, j, mi_row, mi_col, num_bl;
   VP9_COMMON *const cm = &cpi->common;
   uint8_t *y;
   const uint8_t *src_y = cpi->Source->y_buffer;
   const uint8_t *src_u = cpi->Source->u_buffer;
   const uint8_t *src_v = cpi->Source->v_buffer;
   const int src_ystride = cpi->Source->y_stride;
   const int src_uvstride = cpi->Source->uv_stride;
+  int y_bsize = 16;  // Use 8x8 or 16x16.
+  int uv_bsize = y_bsize >> 1;
+  int ypos = y_bsize >> 1;
+  int uvpos = uv_bsize >> 1;
+  int shy = (y_bsize == 8) ? 3 : 4;
+  int shuv = shy - 1;
+  int fac = y_bsize / 8;
+  // Use center pixel or average of center 2x2 pixels.
+  int mode_filter = 1;
   YV12_BUFFER_CONFIG skinmap;
   memset(&skinmap, 0, sizeof(YV12_BUFFER_CONFIG));
-  if (vp9_alloc_frame_buffer(&skinmap, cm->width, cm->height,
+  if (vpx_alloc_frame_buffer(&skinmap, cm->width, cm->height,
                                cm->subsampling_x, cm->subsampling_y,
                                VP9_ENC_BORDER_IN_PIXELS, cm->byte_alignment)) {
-      vp9_free_frame_buffer(&skinmap);
+      vpx_free_frame_buffer(&skinmap);
       return;
   }
   memset(skinmap.buffer_alloc, 128, skinmap.frame_size);
   y = skinmap.y_buffer;
-  // Loop through 8x8 blocks and set skin map based on center pixel of block.
+  // Loop through blocks and set skin map based on center pixel of block.
   // Set y to white for skin block, otherwise set to source with gray scale.
   // Ignore rightmost/bottom boundary blocks.
-  for (mi_row = 0; mi_row < cm->mi_rows - 1; ++mi_row) {
-    for (mi_col = 0; mi_col < cm->mi_cols - 1; ++mi_col) {
-      // Use middle pixel for each 8x8 block for skin detection.
-      // If middle pixel is skin, assign whole 8x8 block to skin.
-      const uint8_t ysource = src_y[4 * src_ystride + 4];
-      const uint8_t usource = src_u[2 * src_uvstride + 2];
-      const uint8_t vsource = src_v[2 * src_uvstride + 2];
+  for (mi_row = 0; mi_row < cm->mi_rows - 1; mi_row += fac) {
+    num_bl = 0;
+    for (mi_col = 0; mi_col < cm->mi_cols - 1; mi_col += fac) {
+      // Select pixel for each block for skin detection.
+      // Use center pixel, or 2x2 average at center.
+      uint8_t ysource = src_y[ypos * src_ystride + ypos];
+      uint8_t usource = src_u[uvpos * src_uvstride + uvpos];
+      uint8_t vsource = src_v[uvpos * src_uvstride + uvpos];
+      uint8_t ysource2 = src_y[(ypos + 1) * src_ystride + ypos];
+      uint8_t usource2 = src_u[(uvpos + 1) * src_uvstride + uvpos];
+      uint8_t vsource2 = src_v[(uvpos + 1) * src_uvstride + uvpos];
+      uint8_t ysource3 = src_y[ypos * src_ystride + (ypos + 1)];
+      uint8_t usource3 = src_u[uvpos * src_uvstride + (uvpos  + 1)];
+      uint8_t vsource3 = src_v[uvpos * src_uvstride + (uvpos +  1)];
+      uint8_t ysource4 = src_y[(ypos + 1) * src_ystride + (ypos + 1)];
+      uint8_t usource4 = src_u[(uvpos + 1) * src_uvstride + (uvpos  + 1)];
+      uint8_t vsource4 = src_v[(uvpos + 1) * src_uvstride + (uvpos +  1)];
+      if (mode_filter == 1) {
+        ysource = (ysource + ysource2 + ysource3 + ysource4) >> 2;
+        usource = (usource + usource2 + usource3 + usource4) >> 2;
+        vsource = (vsource + vsource2 + vsource3 + vsource4) >> 2;
+      }
       const int is_skin = vp9_skin_pixel(ysource, usource, vsource);
-      for (i = 0; i < 8; i++) {
-        for (j = 0; j < 8; j++) {
+      for (i = 0; i < y_bsize; i++) {
+        for (j = 0; j < y_bsize; j++) {
           if (is_skin)
             y[i * src_ystride + j] = 255;
           else
             y[i * src_ystride + j] = src_y[i * src_ystride + j];
         }
       }
-      y += 8;
-      src_y += 8;
-      src_u += 4;
-      src_v += 4;
+      num_bl++;
+      y += y_bsize;
+      src_y += y_bsize;
+      src_u += uv_bsize;
+      src_v += uv_bsize;
     }
-    y += (src_ystride << 3) - ((cm->mi_cols - 1) << 3);
-    src_y += (src_ystride << 3) - ((cm->mi_cols - 1) << 3);
-    src_u += (src_uvstride << 2) - ((cm->mi_cols - 1) << 2);
-    src_v += (src_uvstride << 2) - ((cm->mi_cols - 1) << 2);
+    y += (src_ystride << shy) - (num_bl << shy);
+    src_y += (src_ystride << shy) - (num_bl << shy);
+    src_u += (src_uvstride << shuv) - (num_bl << shuv);
+    src_v += (src_uvstride << shuv) - (num_bl << shuv);
   }
   vp9_write_yuv_frame_420(&skinmap, yuv_skinmap_file);
-  vp9_free_frame_buffer(&skinmap);
+  vpx_free_frame_buffer(&skinmap);
 }
 #endif