/* * 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 #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; static const unsigned int SSE_THRESHOLD_HIGH = 16 * 16 * 60; /* * 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, int increase_denoising) { unsigned char *running_avg_y_start = running_avg_y; unsigned char *sig_start = sig; int sum_diff_thresh; int r, c; int sum_diff = 0; int adj_val[3] = {3, 4, 6}; int shift_inc1 = 0; int shift_inc2 = 1; /* If motion_magnitude is small, making the denoiser more aggressive by * increasing the adjustment for each level. Add another increment for * blocks that are labeled for increase denoising. */ if (motion_magnitude <= MOTION_MAGNITUDE_THRESHOLD) { if (increase_denoising) { shift_inc1 = 1; shift_inc2 = 2; } adj_val[0] += shift_inc2; adj_val[1] += shift_inc2; adj_val[2] += shift_inc2; } 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| <= |3 + shift_inc1|, use pixel value from // last denoised raw. if (absdiff <= 3 + shift_inc1) { 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; } sum_diff_thresh= SUM_DIFF_THRESHOLD; if (increase_denoising) sum_diff_thresh = SUM_DIFF_THRESHOLD_HIGH; if (abs(sum_diff) > sum_diff_thresh) { // Before returning to copy the block (i.e., apply no denoising), check // if we can still apply some (weaker) temporal filtering to this block, // that would otherwise not be denoised at all. Simplest is to apply // an additional adjustment to running_avg_y to bring it closer to sig. // The adjustment is capped by a maximum delta, and chosen such that // in most cases the resulting sum_diff will be within the // accceptable range given by sum_diff_thresh. // The delta is set by the excess of absolute pixel diff over threshold. int delta = ((abs(sum_diff) - sum_diff_thresh) >> 8) + 1; // Only apply the adjustment for max delta up to 3. if (delta < 4) { sig -= sig_stride * 16; mc_running_avg_y -= mc_avg_y_stride * 16; running_avg_y -= avg_y_stride * 16; for (r = 0; r < 16; ++r) { for (c = 0; c < 16; ++c) { int diff = mc_running_avg_y[c] - sig[c]; int adjustment = abs(diff); if (adjustment > delta) adjustment = delta; if (diff > 0) { // Bring denoised signal down. if (running_avg_y[c] - adjustment < 0) running_avg_y[c] = 0; else running_avg_y[c] = running_avg_y[c] - adjustment; sum_diff -= adjustment; } else if (diff < 0) { // Bring denoised signal up. if (running_avg_y[c] + adjustment > 255) running_avg_y[c] = 255; else running_avg_y[c] = running_avg_y[c] + adjustment; sum_diff += adjustment; } } // TODO(marpan): Check here if abs(sum_diff) has gone below the // threshold sum_diff_thresh, and if so, we can exit the row loop. sig += sig_stride; mc_running_avg_y += mc_avg_y_stride; running_avg_y += avg_y_stride; } if (abs(sum_diff) > sum_diff_thresh) return COPY_BLOCK; } else { return COPY_BLOCK; } } vp8_copy_mem16x16(running_avg_y_start, avg_y_stride, sig_start, sig_stride); return FILTER_BLOCK; } int vp8_denoiser_filter_uv_c(unsigned char *mc_running_avg_uv, int mc_avg_uv_stride, unsigned char *running_avg_uv, int avg_uv_stride, unsigned char *sig, int sig_stride, unsigned int motion_magnitude, int increase_denoising) { unsigned char *running_avg_uv_start = running_avg_uv; unsigned char *sig_start = sig; int sum_diff_thresh; int r, c; int sum_diff = 0; int sum_block = 0; int adj_val[3] = {3, 4, 6}; int shift_inc1 = 0; int shift_inc2 = 1; /* If motion_magnitude is small, making the denoiser more aggressive by * increasing the adjustment for each level. Add another increment for * blocks that are labeled for increase denoising. */ if (motion_magnitude <= MOTION_MAGNITUDE_THRESHOLD_UV) { if (increase_denoising) { shift_inc1 = 1; shift_inc2 = 2; } adj_val[0] += shift_inc2; adj_val[1] += shift_inc2; adj_val[2] += shift_inc2; } // Avoid denoising color signal if its close to average level. for (r = 0; r < 8; ++r) { for (c = 0; c < 8; ++c) { sum_block += sig[c]; } sig += sig_stride; } if (abs(sum_block - (128 * 8 * 8)) < SUM_DIFF_FROM_AVG_THRESH_UV) { return COPY_BLOCK; } sig -= sig_stride * 8; for (r = 0; r < 8; ++r) { for (c = 0; c < 8; ++c) { int diff = 0; int adjustment = 0; int absdiff = 0; diff = mc_running_avg_uv[c] - sig[c]; absdiff = abs(diff); // When |diff| <= |3 + shift_inc1|, use pixel value from // last denoised raw. if (absdiff <= 3 + shift_inc1) { running_avg_uv[c] = mc_running_avg_uv[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_uv[c] = 255; else running_avg_uv[c] = sig[c] + adjustment; sum_diff += adjustment; } else { if ((sig[c] - adjustment) < 0) running_avg_uv[c] = 0; else running_avg_uv[c] = sig[c] - adjustment; sum_diff -= adjustment; } } } /* Update pointers for next iteration. */ sig += sig_stride; mc_running_avg_uv += mc_avg_uv_stride; running_avg_uv += avg_uv_stride; } sum_diff_thresh= SUM_DIFF_THRESHOLD_UV; if (increase_denoising) sum_diff_thresh = SUM_DIFF_THRESHOLD_HIGH_UV; if (abs(sum_diff) > sum_diff_thresh) { // Before returning to copy the block (i.e., apply no denoising), check // if we can still apply some (weaker) temporal filtering to this block, // that would otherwise not be denoised at all. Simplest is to apply // an additional adjustment to running_avg_y to bring it closer to sig. // The adjustment is capped by a maximum delta, and chosen such that // in most cases the resulting sum_diff will be within the // accceptable range given by sum_diff_thresh. // The delta is set by the excess of absolute pixel diff over threshold. int delta = ((abs(sum_diff) - sum_diff_thresh) >> 8) + 1; // Only apply the adjustment for max delta up to 3. if (delta < 4) { sig -= sig_stride * 8; mc_running_avg_uv -= mc_avg_uv_stride * 8; running_avg_uv -= avg_uv_stride * 8; for (r = 0; r < 8; ++r) { for (c = 0; c < 8; ++c) { int diff = mc_running_avg_uv[c] - sig[c]; int adjustment = abs(diff); if (adjustment > delta) adjustment = delta; if (diff > 0) { // Bring denoised signal down. if (running_avg_uv[c] - adjustment < 0) running_avg_uv[c] = 0; else running_avg_uv[c] = running_avg_uv[c] - adjustment; sum_diff -= adjustment; } else if (diff < 0) { // Bring denoised signal up. if (running_avg_uv[c] + adjustment > 255) running_avg_uv[c] = 255; else running_avg_uv[c] = running_avg_uv[c] + adjustment; sum_diff += adjustment; } } // TODO(marpan): Check here if abs(sum_diff) has gone below the // threshold sum_diff_thresh, and if so, we can exit the row loop. sig += sig_stride; mc_running_avg_uv += mc_avg_uv_stride; running_avg_uv += avg_uv_stride; } if (abs(sum_diff) > sum_diff_thresh) return COPY_BLOCK; } else { return COPY_BLOCK; } } vp8_copy_mem8x8(running_avg_uv_start, avg_uv_stride, sig_start, sig_stride); return FILTER_BLOCK; } void vp8_denoiser_set_parameters(VP8_DENOISER *denoiser, int mode) { assert(mode > 0); // Denoiser is allocated only if mode > 0. if (mode == 1) { denoiser->denoiser_mode = kDenoiserOnYOnly; } else if (mode == 2) { denoiser->denoiser_mode = kDenoiserOnYUV; } else if (mode == 3) { denoiser->denoiser_mode = kDenoiserOnYUVAggressive; } else { denoiser->denoiser_mode = kDenoiserOnAdaptive; } if (denoiser->denoiser_mode != kDenoiserOnYUVAggressive) { denoiser->denoise_pars.scale_sse_thresh = 1; denoiser->denoise_pars.scale_motion_thresh = 8; denoiser->denoise_pars.scale_increase_filter = 0; denoiser->denoise_pars.denoise_mv_bias = 95; denoiser->denoise_pars.pickmode_mv_bias = 100; denoiser->denoise_pars.qp_thresh = 0; denoiser->denoise_pars.consec_zerolast = UINT_MAX; } else { denoiser->denoise_pars.scale_sse_thresh = 2; denoiser->denoise_pars.scale_motion_thresh = 16; denoiser->denoise_pars.scale_increase_filter = 1; denoiser->denoise_pars.denoise_mv_bias = 60; denoiser->denoise_pars.pickmode_mv_bias = 60; denoiser->denoise_pars.qp_thresh = 100; denoiser->denoise_pars.consec_zerolast = 10; } } int vp8_denoiser_allocate(VP8_DENOISER *denoiser, int width, int height, int num_mb_rows, int num_mb_cols, int mode) { int i; assert(denoiser); denoiser->num_mb_cols = num_mb_cols; 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); if (vp8_yv12_alloc_frame_buffer(&denoiser->yv12_last_source, width, height, VP8BORDERINPIXELS) < 0) { vp8_denoiser_free(denoiser); return 1; } vpx_memset(denoiser->yv12_last_source.buffer_alloc, 0, denoiser->yv12_last_source.frame_size); denoiser->denoise_state = vpx_calloc((num_mb_rows * num_mb_cols), 1); vpx_memset(denoiser->denoise_state, 0, (num_mb_rows * num_mb_cols)); vp8_denoiser_set_parameters(denoiser, mode); denoiser->nmse_source_diff = 0; denoiser->nmse_source_diff_count = 0; // TODO(marpan): Adjust thresholds, including effect on resolution. denoiser->threshold_aggressive_mode = 35; if (width * height > 640 * 480) denoiser->threshold_aggressive_mode = 150; else if (width * height > 1280 * 720) denoiser->threshold_aggressive_mode = 1400; 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); vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_last_source); vpx_free(denoiser->denoise_state); } 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, loop_filter_info_n *lfi_n, int mb_row, int mb_col, int block_index) { int mv_row; int mv_col; unsigned int motion_threshold; unsigned int motion_magnitude2; unsigned int sse_thresh; int sse_diff_thresh = 0; // Spatial loop filter: only applied selectively based on // temporal filter state of block relative to top/left neighbors. int apply_spatial_loop_filter = 1; 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; enum vp8_denoiser_decision decision_u = COPY_BLOCK; enum vp8_denoiser_decision decision_v = COPY_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 = 0; // Bias on zero motion vector sse. const int zero_bias = denoiser->denoise_pars.denoise_mv_bias; zero_mv_sse = (unsigned int)((int64_t)zero_mv_sse * zero_bias / 100); 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; // Bias to zero_mv if small amount of motion. // Note sse_diff_thresh is intialized to zero, so this ensures // we will always choose zero_mv for denoising if // zero_mv_see <= best_sse (i.e., sse_diff <= 0). if ((unsigned int)(mv_row * mv_row + mv_col * mv_col) <= NOISE_MOTION_THRESHOLD) sse_diff_thresh = (int)SSE_DIFF_THRESHOLD; if (frame == INTRA_FRAME || sse_diff <= sse_diff_thresh) { /* * 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; motion_threshold = denoiser->denoise_pars.scale_motion_thresh * NOISE_MOTION_THRESHOLD; if (motion_magnitude2 < denoiser->denoise_pars.scale_increase_filter * NOISE_MOTION_THRESHOLD) x->increase_denoising = 1; sse_thresh = denoiser->denoise_pars.scale_sse_thresh * SSE_THRESHOLD; if (x->increase_denoising) sse_thresh = denoiser->denoise_pars.scale_sse_thresh * SSE_THRESHOLD_HIGH; if (best_sse > sse_thresh || motion_magnitude2 > 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, x->increase_denoising); denoiser->denoise_state[block_index] = motion_magnitude2 > 0 ? kFilterNonZeroMV : kFilterZeroMV; // Only denoise UV for zero motion, and if y channel was denoised. if (denoiser->denoiser_mode != kDenoiserOnYOnly && motion_magnitude2 == 0 && decision == FILTER_BLOCK) { unsigned char *mc_running_avg_u = denoiser->yv12_mc_running_avg.u_buffer + recon_uvoffset; unsigned char *running_avg_u = denoiser->yv12_running_avg[INTRA_FRAME].u_buffer + recon_uvoffset; unsigned char *mc_running_avg_v = denoiser->yv12_mc_running_avg.v_buffer + recon_uvoffset; unsigned char *running_avg_v = denoiser->yv12_running_avg[INTRA_FRAME].v_buffer + recon_uvoffset; int mc_avg_uv_stride = denoiser->yv12_mc_running_avg.uv_stride; int avg_uv_stride = denoiser->yv12_running_avg[INTRA_FRAME].uv_stride; int signal_stride = x->block[16].src_stride; decision_u = vp8_denoiser_filter_uv(mc_running_avg_u, mc_avg_uv_stride, running_avg_u, avg_uv_stride, x->block[16].src + *x->block[16].base_src, signal_stride, motion_magnitude2, 0); decision_v = vp8_denoiser_filter_uv(mc_running_avg_v, mc_avg_uv_stride, running_avg_v, avg_uv_stride, x->block[20].src + *x->block[20].base_src, signal_stride, motion_magnitude2, 0); } } 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); denoiser->denoise_state[block_index] = kNoFilter; } if (denoiser->denoiser_mode != kDenoiserOnYOnly) { if (decision_u == COPY_BLOCK) { vp8_copy_mem8x8( x->block[16].src + *x->block[16].base_src, x->block[16].src_stride, denoiser->yv12_running_avg[INTRA_FRAME].u_buffer + recon_uvoffset, denoiser->yv12_running_avg[INTRA_FRAME].uv_stride); } if (decision_v == COPY_BLOCK) { vp8_copy_mem8x8( x->block[20].src + *x->block[20].base_src, x->block[16].src_stride, denoiser->yv12_running_avg[INTRA_FRAME].v_buffer + recon_uvoffset, denoiser->yv12_running_avg[INTRA_FRAME].uv_stride); } } // Option to selectively deblock the denoised signal, for y channel only. if (apply_spatial_loop_filter) { loop_filter_info lfi; int apply_filter_col = 0; int apply_filter_row = 0; int apply_filter = 0; int y_stride = denoiser->yv12_running_avg[INTRA_FRAME].y_stride; int uv_stride =denoiser->yv12_running_avg[INTRA_FRAME].uv_stride; // Fix filter level to some nominal value for now. int filter_level = 32; int hev_index = lfi_n->hev_thr_lut[INTER_FRAME][filter_level]; lfi.mblim = lfi_n->mblim[filter_level]; lfi.blim = lfi_n->blim[filter_level]; lfi.lim = lfi_n->lim[filter_level]; lfi.hev_thr = lfi_n->hev_thr[hev_index]; // Apply filter if there is a difference in the denoiser filter state // between the current and left/top block, or if non-zero motion vector // is used for the motion-compensated filtering. if (mb_col > 0) { apply_filter_col = !((denoiser->denoise_state[block_index] == denoiser->denoise_state[block_index - 1]) && denoiser->denoise_state[block_index] != kFilterNonZeroMV); if (apply_filter_col) { // Filter left vertical edge. apply_filter = 1; vp8_loop_filter_mbv( denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset, NULL, NULL, y_stride, uv_stride, &lfi); } } if (mb_row > 0) { apply_filter_row = !((denoiser->denoise_state[block_index] == denoiser->denoise_state[block_index - denoiser->num_mb_cols]) && denoiser->denoise_state[block_index] != kFilterNonZeroMV); if (apply_filter_row) { // Filter top horizontal edge. apply_filter = 1; vp8_loop_filter_mbh( denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset, NULL, NULL, y_stride, uv_stride, &lfi); } } if (apply_filter) { // Update the signal block |x|. Pixel changes are only to top and/or // left boundary pixels: can we avoid full block copy here. vp8_copy_mem16x16( denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset, y_stride, x->thismb, 16); } } }