/* * Copyright (c) 2012 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 "denoising.h" #include "vp8/common/reconinter.h" #include "vpx/vpx_integer.h" #include "vpx_mem/vpx_mem.h" #include "vp8_rtcd.h" static const unsigned int NOISE_MOTION_THRESHOLD = 25 * 25; /* SSE_DIFF_THRESHOLD is selected as ~95% confidence assuming * var(noise) ~= 100. */ static const unsigned int SSE_DIFF_THRESHOLD = 16 * 16 * 20; static const unsigned int SSE_THRESHOLD = 16 * 16 * 40; /* * The filter function was modified to reduce the computational complexity. * Step 1: * Instead of applying tap coefficients for each pixel, we calculated the * pixel adjustments vs. pixel diff value ahead of time. * adjustment = filtered_value - current_raw * = (filter_coefficient * diff + 128) >> 8 * where * filter_coefficient = (255 << 8) / (256 + ((absdiff * 330) >> 3)); * filter_coefficient += filter_coefficient / * (3 + motion_magnitude_adjustment); * filter_coefficient is clamped to 0 ~ 255. * * Step 2: * The adjustment vs. diff curve becomes flat very quick when diff increases. * This allowed us to use only several levels to approximate the curve without * changing the filtering algorithm too much. * The adjustments were further corrected by checking the motion magnitude. * The levels used are: * diff adjustment w/o motion correction adjustment w/ motion correction * [-255, -16] -6 -7 * [-15, -8] -4 -5 * [-7, -4] -3 -4 * [-3, 3] diff diff * [4, 7] 3 4 * [8, 15] 4 5 * [16, 255] 6 7 */ int vp8_denoiser_filter_c(unsigned char *mc_running_avg_y, int mc_avg_y_stride, unsigned char *running_avg_y, int avg_y_stride, unsigned char *sig, int sig_stride, unsigned int motion_magnitude) { unsigned char *running_avg_y_start = running_avg_y; unsigned char *sig_start = sig; int r, c, i; int sum_diff = 0; int adj_val[3] = {3, 4, 6}; /* If motion_magnitude is small, making the denoiser more aggressive by * increasing the adjustment for each level. */ if (motion_magnitude <= MOTION_MAGNITUDE_THRESHOLD) { for (i = 0; i < 3; i++) adj_val[i] += 1; } for (r = 0; r < 16; ++r) { for (c = 0; c < 16; ++c) { int diff = 0; int adjustment = 0; int absdiff = 0; diff = mc_running_avg_y[c] - sig[c]; absdiff = abs(diff); /* When |diff| < 4, use pixel value from last denoised raw. */ if (absdiff <= 3) { running_avg_y[c] = mc_running_avg_y[c]; sum_diff += diff; } else { if (absdiff >= 4 && absdiff <= 7) adjustment = adj_val[0]; else if (absdiff >= 8 && absdiff <= 15) adjustment = adj_val[1]; else adjustment = adj_val[2]; if (diff > 0) { if ((sig[c] + adjustment) > 255) running_avg_y[c] = 255; else running_avg_y[c] = sig[c] + adjustment; sum_diff += adjustment; } else { if ((sig[c] - adjustment) < 0) running_avg_y[c] = 0; else running_avg_y[c] = sig[c] - adjustment; sum_diff -= adjustment; } } } /* Update pointers for next iteration. */ sig += sig_stride; mc_running_avg_y += mc_avg_y_stride; running_avg_y += avg_y_stride; } if (abs(sum_diff) > SUM_DIFF_THRESHOLD) return COPY_BLOCK; vp8_copy_mem16x16(running_avg_y_start, avg_y_stride, sig_start, sig_stride); return FILTER_BLOCK; } int vp8_denoiser_allocate(VP8_DENOISER *denoiser, int width, int height) { int i; assert(denoiser); for (i = 0; i < MAX_REF_FRAMES; i++) { denoiser->yv12_running_avg[i].flags = 0; if (vp8_yv12_alloc_frame_buffer(&(denoiser->yv12_running_avg[i]), width, height, VP8BORDERINPIXELS) < 0) { vp8_denoiser_free(denoiser); return 1; } vpx_memset(denoiser->yv12_running_avg[i].buffer_alloc, 0, denoiser->yv12_running_avg[i].frame_size); } denoiser->yv12_mc_running_avg.flags = 0; if (vp8_yv12_alloc_frame_buffer(&(denoiser->yv12_mc_running_avg), width, height, VP8BORDERINPIXELS) < 0) { vp8_denoiser_free(denoiser); return 1; } vpx_memset(denoiser->yv12_mc_running_avg.buffer_alloc, 0, denoiser->yv12_mc_running_avg.frame_size); return 0; } void vp8_denoiser_free(VP8_DENOISER *denoiser) { int i; assert(denoiser); for (i = 0; i < MAX_REF_FRAMES ; i++) { vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_running_avg[i]); } vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_mc_running_avg); } void vp8_denoiser_denoise_mb(VP8_DENOISER *denoiser, MACROBLOCK *x, unsigned int best_sse, unsigned int zero_mv_sse, int recon_yoffset, int recon_uvoffset) { int mv_row; int mv_col; unsigned int motion_magnitude2; MV_REFERENCE_FRAME frame = x->best_reference_frame; MV_REFERENCE_FRAME zero_frame = x->best_zeromv_reference_frame; enum vp8_denoiser_decision decision = FILTER_BLOCK; if (zero_frame) { YV12_BUFFER_CONFIG *src = &denoiser->yv12_running_avg[frame]; YV12_BUFFER_CONFIG *dst = &denoiser->yv12_mc_running_avg; YV12_BUFFER_CONFIG saved_pre,saved_dst; MB_MODE_INFO saved_mbmi; MACROBLOCKD *filter_xd = &x->e_mbd; MB_MODE_INFO *mbmi = &filter_xd->mode_info_context->mbmi; int sse_diff = zero_mv_sse - best_sse; saved_mbmi = *mbmi; /* Use the best MV for the compensation. */ mbmi->ref_frame = x->best_reference_frame; mbmi->mode = x->best_sse_inter_mode; mbmi->mv = x->best_sse_mv; mbmi->need_to_clamp_mvs = x->need_to_clamp_best_mvs; mv_col = x->best_sse_mv.as_mv.col; mv_row = x->best_sse_mv.as_mv.row; if (frame == INTRA_FRAME || ((unsigned int)(mv_row *mv_row + mv_col *mv_col) <= NOISE_MOTION_THRESHOLD && sse_diff < (int)SSE_DIFF_THRESHOLD)) { /* * Handle intra blocks as referring to last frame with zero motion * and let the absolute pixel difference affect the filter factor. * Also consider small amount of motion as being random walk due * to noise, if it doesn't mean that we get a much bigger error. * Note that any changes to the mode info only affects the * denoising. */ mbmi->ref_frame = x->best_zeromv_reference_frame; src = &denoiser->yv12_running_avg[zero_frame]; mbmi->mode = ZEROMV; mbmi->mv.as_int = 0; x->best_sse_inter_mode = ZEROMV; x->best_sse_mv.as_int = 0; best_sse = zero_mv_sse; } saved_pre = filter_xd->pre; saved_dst = filter_xd->dst; /* Compensate the running average. */ filter_xd->pre.y_buffer = src->y_buffer + recon_yoffset; filter_xd->pre.u_buffer = src->u_buffer + recon_uvoffset; filter_xd->pre.v_buffer = src->v_buffer + recon_uvoffset; /* Write the compensated running average to the destination buffer. */ filter_xd->dst.y_buffer = dst->y_buffer + recon_yoffset; filter_xd->dst.u_buffer = dst->u_buffer + recon_uvoffset; filter_xd->dst.v_buffer = dst->v_buffer + recon_uvoffset; if (!x->skip) { vp8_build_inter_predictors_mb(filter_xd); } else { vp8_build_inter16x16_predictors_mb(filter_xd, filter_xd->dst.y_buffer, filter_xd->dst.u_buffer, filter_xd->dst.v_buffer, filter_xd->dst.y_stride, filter_xd->dst.uv_stride); } filter_xd->pre = saved_pre; filter_xd->dst = saved_dst; *mbmi = saved_mbmi; } mv_row = x->best_sse_mv.as_mv.row; mv_col = x->best_sse_mv.as_mv.col; motion_magnitude2 = mv_row * mv_row + mv_col * mv_col; if (best_sse > SSE_THRESHOLD || motion_magnitude2 > 8 * NOISE_MOTION_THRESHOLD) { decision = COPY_BLOCK; } if (decision == FILTER_BLOCK) { unsigned char *mc_running_avg_y = denoiser->yv12_mc_running_avg.y_buffer + recon_yoffset; int mc_avg_y_stride = denoiser->yv12_mc_running_avg.y_stride; unsigned char *running_avg_y = denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset; int avg_y_stride = denoiser->yv12_running_avg[INTRA_FRAME].y_stride; /* Filter. */ decision = vp8_denoiser_filter(mc_running_avg_y, mc_avg_y_stride, running_avg_y, avg_y_stride, x->thismb, 16, motion_magnitude2); } if (decision == COPY_BLOCK) { /* No filtering of this block; it differs too much from the predictor, * or the motion vector magnitude is considered too big. */ vp8_copy_mem16x16( x->thismb, 16, denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset, denoiser->yv12_running_avg[INTRA_FRAME].y_stride); } }