209 lines
8.1 KiB
C
209 lines
8.1 KiB
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.
|
|
*/
|
|
|
|
#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"
|
|
|
|
#define MODEL_MODE 1
|
|
|
|
// Fixed-point skin color model parameters.
|
|
static const int skin_mean[5][2] = {
|
|
{7463, 9614}, {6400, 10240}, {7040, 10240}, {8320, 9280}, {6800, 9614}};
|
|
static const int skin_inv_cov[4] = {4107, 1663, 1663, 2157}; // q16
|
|
static const int skin_threshold[6] = {1570636, 1400000, 800000, 800000, 800000,
|
|
800000}; // q18
|
|
|
|
// Thresholds on luminance.
|
|
static const int y_low = 40;
|
|
static const int y_high = 220;
|
|
|
|
// Evaluates the Mahalanobis distance measure for the input CbCr values.
|
|
static int evaluate_skin_color_difference(int cb, int cr, int idx) {
|
|
const int cb_q6 = cb << 6;
|
|
const int cr_q6 = cr << 6;
|
|
const int cb_diff_q12 =
|
|
(cb_q6 - skin_mean[idx][0]) * (cb_q6 - skin_mean[idx][0]);
|
|
const int cbcr_diff_q12 =
|
|
(cb_q6 - skin_mean[idx][0]) * (cr_q6 - skin_mean[idx][1]);
|
|
const int cr_diff_q12 =
|
|
(cr_q6 - skin_mean[idx][1]) * (cr_q6 - skin_mean[idx][1]);
|
|
const int cb_diff_q2 = (cb_diff_q12 + (1 << 9)) >> 10;
|
|
const int cbcr_diff_q2 = (cbcr_diff_q12 + (1 << 9)) >> 10;
|
|
const int cr_diff_q2 = (cr_diff_q12 + (1 << 9)) >> 10;
|
|
const int skin_diff = skin_inv_cov[0] * cb_diff_q2 +
|
|
skin_inv_cov[1] * cbcr_diff_q2 +
|
|
skin_inv_cov[2] * cbcr_diff_q2 +
|
|
skin_inv_cov[3] * cr_diff_q2;
|
|
return skin_diff;
|
|
}
|
|
|
|
int vp9_skin_pixel(const uint8_t y, const uint8_t cb, const uint8_t cr,
|
|
int motion) {
|
|
if (y < y_low || y > y_high) {
|
|
return 0;
|
|
} else {
|
|
if (MODEL_MODE == 0) {
|
|
return (evaluate_skin_color_difference(cb, cr, 0) < skin_threshold[0]);
|
|
} else {
|
|
int i = 0;
|
|
// Exit on grey.
|
|
if (cb == 128 && cr == 128)
|
|
return 0;
|
|
// Exit on very strong cb.
|
|
if (cb > 150 && cr < 110)
|
|
return 0;
|
|
for (; i < 5; i++) {
|
|
int skin_color_diff = evaluate_skin_color_difference(cb, cr, i);
|
|
if (skin_color_diff < skin_threshold[i + 1]) {
|
|
if (y < 60 && skin_color_diff > 3 * (skin_threshold[i + 1] >> 2))
|
|
return 0;
|
|
else if (motion == 0 &&
|
|
skin_color_diff > (skin_threshold[i + 1] >> 1))
|
|
return 0;
|
|
else
|
|
return 1;
|
|
}
|
|
// Exit if difference is much large than the threshold.
|
|
if (skin_color_diff > (skin_threshold[i + 1] << 3)) {
|
|
return 0;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
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 vp9_skin_pixel(ysource, usource, vsource, motion);
|
|
}
|
|
}
|
|
|
|
|
|
#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;
|
|
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 = 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;
|
|
// 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) {
|
|
// Use 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)];
|
|
ysource = (ysource + ysource2 + ysource3 + ysource4) >> 2;
|
|
usource = (usource + usource2 + usource3 + usource4) >> 2;
|
|
vsource = (vsource + vsource2 + vsource3 + vsource4) >> 2;
|
|
is_skin = vp9_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)
|
|
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])));
|
|
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);
|
|
}
|
|
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];
|
|
}
|
|
}
|
|
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);
|
|
}
|
|
vp9_write_yuv_frame_420(&skinmap, yuv_skinmap_file);
|
|
vpx_free_frame_buffer(&skinmap);
|
|
}
|
|
#endif
|