ref: 327c9bb1da0e0ceac4293ab42fa8c25e8f1706c9
parent: de1a9c77a7e54f6c0dce272850c43251f38b6c6c
author: Jerome Jiang <jianj@google.com>
date: Thu May 25 09:58:20 EDT 2017
Refactor: Move vp8 skin detection to new files. Change-Id: If760f28cbbf22beac1cc9bd1546f13831e9dd3f0
--- /dev/null
+++ b/vp8/common/skin_detection.c
@@ -1,0 +1,104 @@
+/*
+ * 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/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;
+}
+
+// Checks if the input yCbCr values corresponds to skin color.
+int skin_pixel(int y, int cb, int 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 compute_skin_block(const uint8_t *y, const uint8_t *u, const uint8_t *v,
+ int stride, int strideuv, 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 ysource = (y[7 * stride + 7] + y[7 * stride + 8] +
+ y[8 * stride + 7] + y[8 * stride + 8]) >>
+ 2;
+ const int usource = (u[3 * strideuv + 3] + u[3 * strideuv + 4] +
+ u[4 * strideuv + 3] + u[4 * strideuv + 4]) >>
+ 2;
+ const int vsource = (v[3 * strideuv + 3] + v[3 * strideuv + 4] +
+ v[4 * strideuv + 3] + v[4 * strideuv + 4]) >>
+ 2;
+ if (consec_zeromv > 25 && curr_motion_magn == 0) motion = 0;
+ return skin_pixel(ysource, usource, vsource, motion);
+ }
+}
--- /dev/null
+++ b/vp8/common/skin_detection.h
@@ -1,0 +1,30 @@
+/*
+ * 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.
+ */
+
+#ifndef VP8_ENCODER_SKIN_DETECTION_H_
+#define VP8_ENCODER_SKIN_DETECTION_H_
+
+#include "vpx/vpx_integer.h"
+
+#ifdef __cplusplus
+extern "C" {+#endif
+
+int skin_pixel(int y, int cb, int cr, int motion);
+
+int compute_skin_block(const uint8_t *y, const uint8_t *u, const uint8_t *v,
+ int stride, int strideuv, int consec_zeromv,
+ int curr_motion_magn);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif // VP8_ENCODER_SKIN_DETECTION_H_
--- a/vp8/encoder/pickinter.c
+++ b/vp8/encoder/pickinter.c
@@ -25,6 +25,7 @@
#include "vp8/common/reconintra4x4.h"
#include "vpx_dsp/variance.h"
#include "mcomp.h"
+#include "vp8/common/skin_detection.h"
#include "rdopt.h"
#include "vpx_dsp/vpx_dsp_common.h"
#include "vpx_mem/vpx_mem.h"
@@ -36,82 +37,9 @@
extern unsigned int cnt_pm;
#endif
-#define MODEL_MODE 1
-
extern const int vp8_ref_frame_order[MAX_MODES];
extern const MB_PREDICTION_MODE vp8_mode_order[MAX_MODES];
-// Fixed point implementation of a skin color classifier. Skin color
-// is model by a Gaussian distribution in the CbCr color space.
-// See ../../test/skin_color_detector_test.cc where the reference
-// skin color classifier is defined.
-
-// 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
-
-// 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;
-}
-
-// Checks if the input yCbCr values corresponds to skin color.
-static int is_skin_color(int y, int cb, int cr, int consec_zeromv) {- if (y < 40 || y > 220) {- return 0;
- } else {- if (MODEL_MODE == 0) {- return (evaluate_skin_color_difference(cb, cr, 0) < skin_threshold[0]);
- } else {- int i = 0;
- // No skin if block has been zero motion for long consecutive time.
- if (consec_zeromv > 60) return 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 (consec_zeromv > 25 &&
- 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;
- }
- }
-}
-
static int macroblock_corner_grad(unsigned char *signal, int stride,
int offsetx, int offsety, int sgnx,
int sgny) {@@ -760,27 +688,12 @@
#endif
// Check if current macroblock is in skin area.
- {- const int y = (x->src.y_buffer[7 * x->src.y_stride + 7] +
- x->src.y_buffer[7 * x->src.y_stride + 8] +
- x->src.y_buffer[8 * x->src.y_stride + 7] +
- x->src.y_buffer[8 * x->src.y_stride + 8]) >>
- 2;
- const int cb = (x->src.u_buffer[3 * x->src.uv_stride + 3] +
- x->src.u_buffer[3 * x->src.uv_stride + 4] +
- x->src.u_buffer[4 * x->src.uv_stride + 3] +
- x->src.u_buffer[4 * x->src.uv_stride + 4]) >>
- 2;
- const int cr = (x->src.v_buffer[3 * x->src.uv_stride + 3] +
- x->src.v_buffer[3 * x->src.uv_stride + 4] +
- x->src.v_buffer[4 * x->src.uv_stride + 3] +
- x->src.v_buffer[4 * x->src.uv_stride + 4]) >>
- 2;
- x->is_skin = 0;
- if (!cpi->oxcf.screen_content_mode) {- int block_index = mb_row * cpi->common.mb_cols + mb_col;
- x->is_skin = is_skin_color(y, cb, cr, cpi->consec_zero_last[block_index]);
- }
+ x->is_skin = 0;
+ if (!cpi->oxcf.screen_content_mode) {+ int block_index = mb_row * cpi->common.mb_cols + mb_col;
+ x->is_skin = compute_skin_block(
+ x->src.y_buffer, x->src.u_buffer, x->src.v_buffer, x->src.y_stride,
+ x->src.uv_stride, cpi->consec_zero_last[block_index], 0);
}
#if CONFIG_TEMPORAL_DENOISING
if (cpi->oxcf.noise_sensitivity) {--- a/vp8/vp8cx.mk
+++ b/vp8/vp8cx.mk
@@ -61,6 +61,8 @@
VP8_CX_SRCS-yes += encoder/rdopt.c
VP8_CX_SRCS-yes += encoder/segmentation.c
VP8_CX_SRCS-yes += encoder/segmentation.h
+VP8_CX_SRCS-yes += common/skin_detection.c
+VP8_CX_SRCS-yes += common/skin_detection.h
VP8_CX_SRCS-yes += encoder/tokenize.c
VP8_CX_SRCS-yes += encoder/dct_value_cost.h
VP8_CX_SRCS-yes += encoder/dct_value_tokens.h