From 56435bb7b6ed888572c8a20ce873e95afd9f1ee9 Mon Sep 17 00:00:00 2001 From: Marco Date: Tue, 3 Feb 2015 12:34:37 -0800 Subject: Add skin detection. Simple skin detection, from vp8; works reasonable on most of the RTC clips, but could miss sometimes. Added debug flag to write out skin map over source input. Change-Id: I2caea7592f1c459047aac46627eeb24a94946464 --- vp9/encoder/vp9_encoder.c | 21 ++++++-- vp9/encoder/vp9_skin_detection.c | 104 +++++++++++++++++++++++++++++++++++++++ vp9/encoder/vp9_skin_detection.h | 35 +++++++++++++ vp9/vp9cx.mk | 2 + 4 files changed, 157 insertions(+), 5 deletions(-) create mode 100644 vp9/encoder/vp9_skin_detection.c create mode 100644 vp9/encoder/vp9_skin_detection.h (limited to 'vp9') diff --git a/vp9/encoder/vp9_encoder.c b/vp9/encoder/vp9_encoder.c index eda38ff3d..e2ed95c3e 100644 --- a/vp9/encoder/vp9_encoder.c +++ b/vp9/encoder/vp9_encoder.c @@ -50,6 +50,7 @@ #include "vp9/encoder/vp9_temporal_filter.h" #include "vp9/encoder/vp9_resize.h" #include "vp9/encoder/vp9_svc_layercontext.h" +#include "vp9/encoder/vp9_skin_detection.h" #define SHARP_FILTER_QTHRESH 0 /* Q threshold for 8-tap sharp filter */ @@ -60,12 +61,14 @@ // mv. Choose a very high value for // now so that HIGH_PRECISION is always // chosen. - // #define OUTPUT_YUV_REC #ifdef OUTPUT_YUV_DENOISED FILE *yuv_denoised_file = NULL; #endif +#ifdef OUTPUT_YUV_SKINMAP +FILE *yuv_skinmap_file = NULL; +#endif #ifdef OUTPUT_YUV_REC FILE *yuv_rec_file; #endif @@ -1541,6 +1544,9 @@ VP9_COMP *vp9_create_compressor(VP9EncoderConfig *oxcf, yuv_denoised_file = fopen("denoised.yuv", "ab"); #endif #endif +#ifdef OUTPUT_YUV_SKINMAP + yuv_skinmap_file = fopen("skinmap.yuv", "ab"); +#endif #ifdef OUTPUT_YUV_REC yuv_rec_file = fopen("rec.yuv", "wb"); #endif @@ -1829,6 +1835,9 @@ void vp9_remove_compressor(VP9_COMP *cpi) { fclose(yuv_denoised_file); #endif #endif +#ifdef OUTPUT_YUV_SKINMAP + fclose(yuv_skinmap_file); +#endif #ifdef OUTPUT_YUV_REC fclose(yuv_rec_file); #endif @@ -2116,8 +2125,7 @@ int vp9_update_entropy(VP9_COMP * cpi, int update) { return 0; } -#if CONFIG_VP9_TEMPORAL_DENOISING -#if defined(OUTPUT_YUV_DENOISED) +#if defined(OUTPUT_YUV_DENOISED) || defined(OUTPUT_YUV_SKINMAP) // The denoiser buffer is allocated as a YUV 440 buffer. This function writes it // as YUV 420. We simply use the top-left pixels of the UV buffers, since we do // not denoise the UV channels at this time. If ever we implement UV channel @@ -2148,7 +2156,6 @@ void vp9_write_yuv_frame_420(YV12_BUFFER_CONFIG *s, FILE *f) { } while (--h); } #endif -#endif #ifdef OUTPUT_YUV_REC void vp9_write_yuv_rec_frame(VP9_COMMON *cm) { @@ -3299,7 +3306,11 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi, } #endif #endif - +#ifdef OUTPUT_YUV_SKINMAP + if (cpi->common.current_video_frame > 1) { + vp9_compute_skin_map(cpi, yuv_skinmap_file); + } +#endif // Special case code to reduce pulsing when key frames are forced at a // fixed interval. Note the reconstruction error if it is the frame before diff --git a/vp9/encoder/vp9_skin_detection.c b/vp9/encoder/vp9_skin_detection.c new file mode 100644 index 000000000..08ebcf8f1 --- /dev/null +++ b/vp9/encoder/vp9_skin_detection.c @@ -0,0 +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 +#include + +#include "vp9/common/vp9_blockd.h" +#include "vp9/encoder/vp9_encoder.h" +#include "vp9/encoder/vp9_skin_detection.h" + +// Fixed-point skin color model parameters. +static const int skin_mean[2] = {7463, 9614}; // q6 +static const int skin_inv_cov[4] = {4107, 1663, 1663, 2157}; // q16 +static const int skin_threshold = 1570636; // q18 + +// Thresholds on luminance. +static const int y_low = 20; +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) { + const int cb_q6 = cb << 6; + const int cr_q6 = cr << 6; + const int cb_diff_q12 = (cb_q6 - skin_mean[0]) * (cb_q6 - skin_mean[0]); + const int cbcr_diff_q12 = (cb_q6 - skin_mean[0]) * (cr_q6 - skin_mean[1]); + const int cr_diff_q12 = (cr_q6 - skin_mean[1]) * (cr_q6 - skin_mean[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) { + if (y < y_low || y > y_high) + return 0; + else + return (evaluate_skin_color_difference(cb, cr) < skin_threshold); +} + +#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; + 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; + YV12_BUFFER_CONFIG skinmap; + vpx_memset(&skinmap, 0, sizeof(YV12_BUFFER_CONFIG)); + if (vp9_alloc_frame_buffer(&skinmap, cm->width, cm->height, + cm->subsampling_x, cm->subsampling_y, + VP9_ENC_BORDER_IN_PIXELS, cm->byte_alignment)) { + vp9_free_frame_buffer(&skinmap); + return; + } + vpx_memset(skinmap.buffer_alloc, 128, skinmap.frame_size); + y = skinmap.y_buffer; + // Loop through 8x8 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) { + for (mi_col = 0; mi_col < cm->mi_cols - 1; ++mi_col) { + // Use middle pixel for each 8x8 block for skin detection. + // If middle pixel is skin, assign whole 8x8 block to skin. + const uint8_t ysource = src_y[4 * src_ystride + 4]; + const uint8_t usource = src_u[2 * src_uvstride + 2]; + const uint8_t vsource = src_v[2 * src_uvstride + 2]; + const int is_skin = vp9_skin_pixel(ysource, usource, vsource); + for (i = 0; i < 8; i++) { + for (j = 0; j < 8; j++) { + if (is_skin) + y[i * src_ystride + j] = 255; + else + y[i * src_ystride + j] = src_y[i * src_ystride + j]; + } + } + y += 8; + src_y += 8; + src_u += 4; + src_v += 4; + } + y += (src_ystride << 3) - ((cm->mi_cols - 1) << 3); + src_y += (src_ystride << 3) - ((cm->mi_cols - 1) << 3); + src_u += (src_uvstride << 2) - ((cm->mi_cols - 1) << 2); + src_v += (src_uvstride << 2) - ((cm->mi_cols - 1) << 2); + } + vp9_write_yuv_frame_420(&skinmap, yuv_skinmap_file); + vp9_free_frame_buffer(&skinmap); +} +#endif diff --git a/vp9/encoder/vp9_skin_detection.h b/vp9/encoder/vp9_skin_detection.h new file mode 100644 index 000000000..3d4e7375f --- /dev/null +++ b/vp9/encoder/vp9_skin_detection.h @@ -0,0 +1,35 @@ +/* + * 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 VP9_ENCODER_VP9_SKIN_MAP_H_ +#define VP9_ENCODER_VP9_SKIN_MAP_H_ + +#include "vp9/common/vp9_blockd.h" + +#ifdef __cplusplus +extern "C" { +#endif + +struct VP9_COMP; + +// #define OUTPUT_YUV_SKINMAP + +int vp9_skin_pixel(const uint8_t y, const uint8_t cb, const uint8_t cr); + +#ifdef OUTPUT_YUV_SKINMAP +// For viewing skin map on input source. +void vp9_compute_skin_map(VP9_COMP *const cpi, FILE *yuv_skinmap_file); +#endif + +#ifdef __cplusplus +} // extern "C" +#endif + +#endif // VP9_ENCODER_VP9_SKIN_MAP_H_ diff --git a/vp9/vp9cx.mk b/vp9/vp9cx.mk index fbdd4bad5..2b3f8945a 100644 --- a/vp9/vp9cx.mk +++ b/vp9/vp9cx.mk @@ -88,6 +88,8 @@ VP9_CX_SRCS-yes += encoder/vp9_aq_cyclicrefresh.c VP9_CX_SRCS-yes += encoder/vp9_aq_cyclicrefresh.h VP9_CX_SRCS-yes += encoder/vp9_aq_complexity.c VP9_CX_SRCS-yes += encoder/vp9_aq_complexity.h +VP9_CX_SRCS-yes += encoder/vp9_skin_detection.c +VP9_CX_SRCS-yes += encoder/vp9_skin_detection.h ifeq ($(CONFIG_VP9_POSTPROC),yes) VP9_CX_SRCS-$(CONFIG_INTERNAL_STATS) += common/vp9_postproc.h VP9_CX_SRCS-$(CONFIG_INTERNAL_STATS) += common/vp9_postproc.c -- cgit v1.2.3