ref: a9299113397b234e979e5406607f39d40f82d9fa
dir: /vp8/common/vp8_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.
*/
#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 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;
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.
// Ignore rightmost/bottom boundary blocks.
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) {
int is_skin = 0;
int consec_zeromv = 0;
const int bl_index = mb_row * cm->mb_cols + mb_col;
const int bl_index1 = bl_index + 1;
const int bl_index2 = bl_index + cm->mb_cols;
const int bl_index3 = bl_index2 + 1;
consec_zeromv = VPXMIN(cpi->consec_zero_last[bl_index],
VPXMIN(cpi->consec_zero_last[bl_index1],
VPXMIN(cpi->consec_zero_last[bl_index2],
cpi->consec_zero_last[bl_index3])));
is_skin =
vp8_compute_skin_block(src_y, src_u, src_v, src_ystride, src_uvstride,
SKIN_8X8, consec_zeromv, 0);
for (i = 0; i < 16; i++) {
for (j = 0; j < 16; 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 += 16;
src_y += 16;
src_u += 8;
src_v += 8;
}
y += (src_ystride << 4) - (num_bl << 4);
src_y += (src_ystride << 4) - (num_bl << 4);
src_u += (src_uvstride << 3) - (num_bl << 3);
src_v += (src_uvstride << 3) - (num_bl << 3);
}
vpx_write_yuv_frame(yuv_skinmap_file, &skinmap);
vpx_free_frame_buffer(&skinmap);
}
#endif // OUTPUT_YUV_SKINMAP