/*

 *  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.

 */

#include <limits.h>

#include <math.h>

#include "vp9/common/vp9_blockd.h"

#include "vp9/encoder/vp9_encoder.h"

#include "vp9/encoder/vp9_skin_detection.h"

int vp9_compute_skin_block(const uint8_t *y, const uint8_t *u, const uint8_t *v,

                           int stride, int strideuv, int bsize,

                           int consec_zeromv, int curr_motion_magn) {

  // No skin if block has been zero/small motion for long consecutive time.

  if (consec_zeromv > 60 && curr_motion_magn == 0) {

    return 0;

  } else {

    int motion = 1;

    // Take center pixel in block to determine is_skin.

    const int y_width_shift = (4 << b_width_log2_lookup[bsize]) >> 1;

    const int y_height_shift = (4 << b_height_log2_lookup[bsize]) >> 1;

    const int uv_width_shift = y_width_shift >> 1;

    const int uv_height_shift = y_height_shift >> 1;

    const uint8_t ysource = y[y_height_shift * stride + y_width_shift];

    const uint8_t usource = u[uv_height_shift * strideuv + uv_width_shift];

    const uint8_t vsource = v[uv_height_shift * strideuv + uv_width_shift];

    if (consec_zeromv > 25 && curr_motion_magn == 0) motion = 0;

    return vpx_skin_pixel(ysource, usource, vsource, motion);

  }

}

void vp9_compute_skin_sb(VP9_COMP *const cpi, BLOCK_SIZE bsize, int mi_row,

                         int mi_col) {

  int i, j, num_bl;

  VP9_COMMON *const cm = &cpi->common;

  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;

  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;

  const int y_shift = src_ystride * (mi_row << 3) + (mi_col << 3);

  const int uv_shift = src_uvstride * (mi_row << 2) + (mi_col << 2);

  const int mi_row_limit = VPXMIN(mi_row + 8, cm->mi_rows - 2);

  const int mi_col_limit = VPXMIN(mi_col + 8, cm->mi_cols - 2);

  src_y += y_shift;

  src_u += uv_shift;

  src_v += uv_shift;

  for (i = mi_row; i < mi_row_limit; i += fac) {

    num_bl = 0;

    for (j = mi_col; j < mi_col_limit; j += fac) {

      int consec_zeromv = 0;

      int bl_index = i * cm->mi_cols + j;

      int bl_index1 = bl_index + 1;

      int bl_index2 = bl_index + cm->mi_cols;

      int bl_index3 = bl_index2 + 1;

      // Don't detect skin on the boundary.

      if (i == 0 || j == 0) continue;

      if (bsize == BLOCK_8X8)

        consec_zeromv = cpi->consec_zero_mv[bl_index];

      else

        consec_zeromv = VPXMIN(cpi->consec_zero_mv[bl_index],

                               VPXMIN(cpi->consec_zero_mv[bl_index1],

                                      VPXMIN(cpi->consec_zero_mv[bl_index2],

                                             cpi->consec_zero_mv[bl_index3])));

      cpi->skin_map[bl_index] =

          vp9_compute_skin_block(src_y, src_u, src_v, src_ystride, src_uvstride,

                                 bsize, consec_zeromv, 0);

      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);

  }

  // Remove isolated skin blocks (none of its neighbors are skin) and isolated

  // non-skin blocks (all of its neighbors are skin).

  // Skip 4 corner blocks which have only 3 neighbors to remove isolated skin

  // blocks. Skip superblock borders to remove isolated non-skin blocks.

  for (i = mi_row; i < mi_row_limit; i += fac) {

    for (j = mi_col; j < mi_col_limit; j += fac) {

      int bl_index = i * cm->mi_cols + j;

      int num_neighbor = 0;

      int mi, mj;

      int non_skin_threshold = 8;

      // Skip 4 corners.

      if ((i == mi_row && (j == mi_col || j == mi_col_limit - fac)) ||

          (i == mi_row_limit - fac && (j == mi_col || j == mi_col_limit - fac)))

        continue;

      // There are only 5 neighbors for non-skin blocks on the border.

      if (i == mi_row || i == mi_row_limit - fac || j == mi_col ||

          j == mi_col_limit - fac)

        non_skin_threshold = 5;

      for (mi = -fac; mi <= fac; mi += fac) {

        for (mj = -fac; mj <= fac; mj += fac) {

          if (i + mi >= mi_row && i + mi < mi_row_limit && j + mj >= mi_col &&

              j + mj < mi_col_limit) {

            int bl_neighbor_index = (i + mi) * cm->mi_cols + j + mj;

            if (cpi->skin_map[bl_neighbor_index]) num_neighbor++;

          }

        }

      }

      if (cpi->skin_map[bl_index] && num_neighbor < 2)

        cpi->skin_map[bl_index] = 0;

      if (!cpi->skin_map[bl_index] && num_neighbor == non_skin_threshold)

        cpi->skin_map[bl_index] = 1;

    }

  }

}

#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++) {

          y[i * src_ystride + j] = is_skin ? 255 : src_y[i * src_ystride + j];

        }

      }

      num_bl++;

      y += y_bsize;

      src_y += y_bsize;

    }

    y += (src_ystride << shy) - (num_bl << shy);

    src_y += (src_ystride << shy) - (num_bl << shy);

  }

  vpx_write_yuv_frame(yuv_skinmap_file, &skinmap);

  vpx_free_frame_buffer(&skinmap);

}

#endif