vp9: compute skinmap only once before encoding.

This could save some cycles since skin detection is used in multiple
places in vp9.

1~2% speed up on ARM.

Change-Id: I86b731945f85215bbb0976021cd0f2040ff2687c

1 files changed, 58 insertions, 38 deletions

diff --git a/vp9/encoder/vp9_skin_detection.c b/vp9/encoder/vp9_skin_detection.c
index 175503ed4..cf6b364fe 100644
--- a/vp9/encoder/vp9_skin_detection.c
+++ b/vp9/encoder/vp9_skin_detection.c
@@ -36,44 +36,31 @@ int vp9_compute_skin_block(const uint8_t *y, const uint8_t *u, const uint8_t *v,
   }
 }
 
-#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, num_bl;
+void vp9_compute_skin_map(VP9_COMP *const cpi, BLOCK_SIZE bsize) {
+  int 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;
+  const int y_bsize = 4 << b_width_log2_lookup[bsize];
+  const int uv_bsize = y_bsize >> 1;
+  const int shy = (y_bsize == 8) ? 3 : 4;
+  const int shuv = shy - 1;
+  const int fac = y_bsize / 8;
   // Use center pixel or average of center 2x2 pixels.
-  int mode_filter = 0;
-  YV12_BUFFER_CONFIG skinmap;
-  memset(&skinmap, 0, sizeof(YV12_BUFFER_CONFIG));
-  if (vpx_alloc_frame_buffer(&skinmap, cm->width, cm->height, cm->subsampling_x,
-                             cm->subsampling_y, VP9_ENC_BORDER_IN_PIXELS,
-                             cm->byte_alignment)) {
-    vpx_free_frame_buffer(&skinmap);
-    return;
-  }
-  memset(skinmap.buffer_alloc, 128, skinmap.frame_size);
-  y = skinmap.y_buffer;
+  const int mode_filter = 0;
+
   // 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 += fac) {
     num_bl = 0;
     for (mi_col = 0; mi_col < cm->mi_cols - 1; mi_col += fac) {
       int is_skin = 0;
       if (mode_filter == 1) {
+        const int ypos = y_bsize >> 1;
+        const int uvpos = uv_bsize >> 1;
         // Use 2x2 average at center.
         uint8_t ysource = src_y[ypos * src_ystride + ypos];
         uint8_t usource = src_u[uvpos * src_uvstride + uvpos];
@@ -92,13 +79,12 @@ void vp9_compute_skin_map(VP9_COMP *const cpi, FILE *yuv_skinmap_file) {
         vsource = (vsource + vsource2 + vsource3 + vsource4) >> 2;
         is_skin = vpx_skin_pixel(ysource, usource, vsource, 1);
       } else {
-        int block_size = BLOCK_8X8;
         int consec_zeromv = 0;
         int bl_index = mi_row * cm->mi_cols + mi_col;
         int bl_index1 = bl_index + 1;
         int bl_index2 = bl_index + cm->mi_cols;
         int bl_index3 = bl_index2 + 1;
-        if (y_bsize == 8)
+        if (bsize == BLOCK_8X8)
           consec_zeromv = cpi->consec_zero_mv[bl_index];
         else
           consec_zeromv =
@@ -106,29 +92,63 @@ void vp9_compute_skin_map(VP9_COMP *const cpi, FILE *yuv_skinmap_file) {
                      VPXMIN(cpi->consec_zero_mv[bl_index1],
                             VPXMIN(cpi->consec_zero_mv[bl_index2],
                                    cpi->consec_zero_mv[bl_index3])));
-        if (y_bsize == 16) block_size = BLOCK_16X16;
-        is_skin =
-            vp9_compute_skin_block(src_y, src_u, src_v, src_ystride,
-                                   src_uvstride, block_size, consec_zeromv, 0);
+        is_skin = vp9_compute_skin_block(src_y, src_u, src_v, src_ystride,
+                                         src_uvstride, bsize, consec_zeromv, 0);
       }
+      cpi->skin_map[mi_row * cm->mi_cols + mi_col] = is_skin;
+      num_bl++;
+      src_y += y_bsize;
+      src_u += uv_bsize;
+      src_v += uv_bsize;
+    }
+    src_y += (src_ystride << shy) - (num_bl << shy);
+    src_u += (src_uvstride << shuv) - (num_bl << shuv);
+    src_v += (src_uvstride << shuv) - (num_bl << shuv);
+  }
+}
+
+#ifdef OUTPUT_YUV_SKINMAP
+// For viewing skin map on input source.
+void vp9_output_skin_map(VP9_COMP *const cpi, FILE *yuv_skinmap_file) {
+  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 int src_ystride = cpi->Source->y_stride;
+
+  const int y_bsize = 16;  // Use 8x8 or 16x16.
+  const int shy = (y_bsize == 8) ? 3 : 4;
+  const int fac = y_bsize / 8;
+
+  YV12_BUFFER_CONFIG skinmap;
+  memset(&skinmap, 0, sizeof(YV12_BUFFER_CONFIG));
+  if (vpx_alloc_frame_buffer(&skinmap, cm->width, cm->height, cm->subsampling_x,
+                             cm->subsampling_y, VP9_ENC_BORDER_IN_PIXELS,
+                             cm->byte_alignment)) {
+    vpx_free_frame_buffer(&skinmap);
+    return;
+  }
+  memset(skinmap.buffer_alloc, 128, skinmap.frame_size);
+  y = skinmap.y_buffer;
+  // 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 += fac) {
+    num_bl = 0;
+    for (mi_col = 0; mi_col < cm->mi_cols - 1; mi_col += fac) {
+      const int block_index = mi_row * cm->mi_cols + mi_col;
+      const int is_skin = cpi->skin_map[block_index];
       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[i * src_ystride + j] = is_skin ? 255 : src_y[i * src_ystride + j];
         }
       }
       num_bl++;
       y += y_bsize;
       src_y += y_bsize;
-      src_u += uv_bsize;
-      src_v += uv_bsize;
     }
     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);
   }
   vpx_write_yuv_frame(yuv_skinmap_file, &skinmap);
   vpx_free_frame_buffer(&skinmap);