/*

 *  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 "vp8/common/alloccommon.h"

#include "vp8/common/vp8_skin_detection.h"

#include "vpx_dsp/vpx_dsp_common.h"

#include "vpx_mem/vpx_mem.h"

#include "vpx_util/vpx_write_yuv_frame.h"

static int avg_2x2(const uint8_t *s, int p) {

  int i, j;

  int sum = 0;

  for (i = 0; i < 2; ++i, s += p) {

    for (j = 0; j < 2; ++j) {

      sum += s[j];

    }

  }

  return (sum + 2) >> 2;

}

int vp8_compute_skin_block(const uint8_t *y, const uint8_t *u, const uint8_t *v,

                           int stride, int strideuv,

                           SKIN_DETECTION_BLOCK_SIZE 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;

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

    if (bsize == SKIN_16X16) {

      // Take the average of center 2x2 pixels.

      const int ysource = avg_2x2(y + 7 * stride + 7, stride);

      const int usource = avg_2x2(u + 3 * strideuv + 3, strideuv);

      const int vsource = avg_2x2(v + 3 * strideuv + 3, strideuv);

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

    } else {

      int num_skin = 0;

      int i, j;

      for (i = 0; i < 2; i++) {

        for (j = 0; j < 2; j++) {

          // Take the average of center 2x2 pixels.

          const int ysource = avg_2x2(y + 3 * stride + 3, stride);

          const int usource = avg_2x2(u + strideuv + 1, strideuv);

          const int vsource = avg_2x2(v + strideuv + 1, strideuv);

          num_skin += vpx_skin_pixel(ysource, usource, vsource, motion);

          if (num_skin >= 2) return 1;

          y += 8;

          u += 4;

          v += 4;

        }

        y += (stride << 3) - 16;

        u += (strideuv << 2) - 8;

        v += (strideuv << 2) - 8;

      }

      return 0;

    }

  }

}

#ifdef OUTPUT_YUV_SKINMAP

// For viewing skin map on input source.

void vp8_compute_skin_map(VP8_COMP *const cpi, FILE *yuv_skinmap_file) {

  int i, j, mb_row, mb_col, num_bl;

  VP8_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;

  int offset = 0;

  YV12_BUFFER_CONFIG skinmap;

  memset(&skinmap, 0, sizeof(skinmap));

  if (vp8_yv12_alloc_frame_buffer(&skinmap, cm->Width, cm->Height,

                                  VP8BORDERINPIXELS) < 0) {

    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.

  for (mb_row = 0; mb_row < cm->mb_rows; mb_row += 1) {

    num_bl = 0;

    for (mb_col = 0; mb_col < cm->mb_cols; mb_col += 1) {

      const int is_skin = cpi->skin_map[offset++];

      for (i = 0; i < 16; i++) {

        for (j = 0; j < 16; j++) {

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

        }

      }

      num_bl++;

      y += 16;

      src_y += 16;

    }

    y += (src_ystride << 4) - (num_bl << 4);

    src_y += (src_ystride << 4) - (num_bl << 4);

  }

  vpx_write_yuv_frame(yuv_skinmap_file, &skinmap);

  vpx_free_frame_buffer(&skinmap);

}

#endif  // OUTPUT_YUV_SKINMAP