d08b2ba172
Allow for an option to selectively apply the deblocking loop filter to the denoised raw block, based on the denoised state (no-filter, filter with zero motion, or filter with non-zero motion) of the current block and its upper and left denoised block. This helps to reduce some blocking artifacts from the motion-compensated denoising. Change-Id: I0ac4e70076df69a98c5391979e739a2681e24ae6
446 lines
17 KiB
C
446 lines
17 KiB
C
/*
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* Copyright (c) 2012 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "denoising.h"
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#include "vp8/common/reconinter.h"
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#include "vpx/vpx_integer.h"
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#include "vpx_mem/vpx_mem.h"
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#include "vp8_rtcd.h"
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static const unsigned int NOISE_MOTION_THRESHOLD = 25 * 25;
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/* SSE_DIFF_THRESHOLD is selected as ~95% confidence assuming
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* var(noise) ~= 100.
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*/
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static const unsigned int SSE_DIFF_THRESHOLD = 16 * 16 * 20;
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static const unsigned int SSE_THRESHOLD = 16 * 16 * 40;
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static const unsigned int SSE_THRESHOLD_HIGH = 16 * 16 * 60;
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/*
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* The filter function was modified to reduce the computational complexity.
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* Step 1:
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* Instead of applying tap coefficients for each pixel, we calculated the
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* pixel adjustments vs. pixel diff value ahead of time.
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* adjustment = filtered_value - current_raw
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* = (filter_coefficient * diff + 128) >> 8
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* where
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* filter_coefficient = (255 << 8) / (256 + ((absdiff * 330) >> 3));
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* filter_coefficient += filter_coefficient /
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* (3 + motion_magnitude_adjustment);
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* filter_coefficient is clamped to 0 ~ 255.
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*
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* Step 2:
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* The adjustment vs. diff curve becomes flat very quick when diff increases.
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* This allowed us to use only several levels to approximate the curve without
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* changing the filtering algorithm too much.
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* The adjustments were further corrected by checking the motion magnitude.
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* The levels used are:
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* diff adjustment w/o motion correction adjustment w/ motion correction
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* [-255, -16] -6 -7
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* [-15, -8] -4 -5
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* [-7, -4] -3 -4
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* [-3, 3] diff diff
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* [4, 7] 3 4
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* [8, 15] 4 5
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* [16, 255] 6 7
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*/
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int vp8_denoiser_filter_c(unsigned char *mc_running_avg_y, int mc_avg_y_stride,
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unsigned char *running_avg_y, int avg_y_stride,
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unsigned char *sig, int sig_stride,
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unsigned int motion_magnitude,
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int increase_denoising)
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{
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unsigned char *running_avg_y_start = running_avg_y;
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unsigned char *sig_start = sig;
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int sum_diff_thresh;
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int r, c;
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int sum_diff = 0;
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int adj_val[3] = {3, 4, 6};
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int shift_inc1 = 0;
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int shift_inc2 = 1;
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/* If motion_magnitude is small, making the denoiser more aggressive by
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* increasing the adjustment for each level. Add another increment for
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* blocks that are labeled for increase denoising. */
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if (motion_magnitude <= MOTION_MAGNITUDE_THRESHOLD)
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{
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if (increase_denoising) {
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shift_inc1 = 1;
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shift_inc2 = 2;
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}
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adj_val[0] += shift_inc2;
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adj_val[1] += shift_inc2;
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adj_val[2] += shift_inc2;
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}
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for (r = 0; r < 16; ++r)
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{
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for (c = 0; c < 16; ++c)
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{
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int diff = 0;
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int adjustment = 0;
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int absdiff = 0;
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diff = mc_running_avg_y[c] - sig[c];
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absdiff = abs(diff);
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// When |diff| <= |3 + shift_inc1|, use pixel value from
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// last denoised raw.
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if (absdiff <= 3 + shift_inc1)
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{
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running_avg_y[c] = mc_running_avg_y[c];
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sum_diff += diff;
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}
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else
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{
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if (absdiff >= 4 && absdiff <= 7)
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adjustment = adj_val[0];
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else if (absdiff >= 8 && absdiff <= 15)
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adjustment = adj_val[1];
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else
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adjustment = adj_val[2];
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if (diff > 0)
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{
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if ((sig[c] + adjustment) > 255)
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running_avg_y[c] = 255;
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else
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running_avg_y[c] = sig[c] + adjustment;
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sum_diff += adjustment;
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}
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else
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{
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if ((sig[c] - adjustment) < 0)
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running_avg_y[c] = 0;
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else
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running_avg_y[c] = sig[c] - adjustment;
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sum_diff -= adjustment;
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}
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}
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}
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/* Update pointers for next iteration. */
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sig += sig_stride;
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mc_running_avg_y += mc_avg_y_stride;
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running_avg_y += avg_y_stride;
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}
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sum_diff_thresh= SUM_DIFF_THRESHOLD;
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if (increase_denoising) sum_diff_thresh = SUM_DIFF_THRESHOLD_HIGH;
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if (abs(sum_diff) > sum_diff_thresh) {
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// Before returning to copy the block (i.e., apply no denoising), check
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// if we can still apply some (weaker) temporal filtering to this block,
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// that would otherwise not be denoised at all. Simplest is to apply
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// an additional adjustment to running_avg_y to bring it closer to sig.
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// The adjustment is capped by a maximum delta, and chosen such that
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// in most cases the resulting sum_diff will be within the
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// accceptable range given by sum_diff_thresh.
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// The delta is set by the excess of absolute pixel diff over threshold.
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int delta = ((abs(sum_diff) - sum_diff_thresh) >> 8) + 1;
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// Only apply the adjustment for max delta up to 3.
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if (delta < 4) {
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sig -= sig_stride * 16;
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mc_running_avg_y -= mc_avg_y_stride * 16;
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running_avg_y -= avg_y_stride * 16;
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for (r = 0; r < 16; ++r) {
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for (c = 0; c < 16; ++c) {
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int diff = mc_running_avg_y[c] - sig[c];
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int adjustment = abs(diff);
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if (adjustment > delta)
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adjustment = delta;
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if (diff > 0) {
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// Bring denoised signal down.
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if (running_avg_y[c] - adjustment < 0)
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running_avg_y[c] = 0;
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else
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running_avg_y[c] = running_avg_y[c] - adjustment;
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sum_diff -= adjustment;
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} else if (diff < 0) {
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// Bring denoised signal up.
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if (running_avg_y[c] + adjustment > 255)
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running_avg_y[c] = 255;
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else
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running_avg_y[c] = running_avg_y[c] + adjustment;
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sum_diff += adjustment;
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}
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}
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// TODO(marpan): Check here if abs(sum_diff) has gone below the
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// threshold sum_diff_thresh, and if so, we can exit the row loop.
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sig += sig_stride;
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mc_running_avg_y += mc_avg_y_stride;
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running_avg_y += avg_y_stride;
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}
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if (abs(sum_diff) > sum_diff_thresh)
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return COPY_BLOCK;
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} else {
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return COPY_BLOCK;
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}
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}
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vp8_copy_mem16x16(running_avg_y_start, avg_y_stride, sig_start, sig_stride);
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return FILTER_BLOCK;
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}
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int vp8_denoiser_allocate(VP8_DENOISER *denoiser, int width, int height,
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int num_mb_rows, int num_mb_cols)
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{
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int i;
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assert(denoiser);
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denoiser->num_mb_cols = num_mb_cols;
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for (i = 0; i < MAX_REF_FRAMES; i++)
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{
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denoiser->yv12_running_avg[i].flags = 0;
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if (vp8_yv12_alloc_frame_buffer(&(denoiser->yv12_running_avg[i]), width,
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height, VP8BORDERINPIXELS)
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< 0)
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{
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vp8_denoiser_free(denoiser);
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return 1;
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}
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vpx_memset(denoiser->yv12_running_avg[i].buffer_alloc, 0,
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denoiser->yv12_running_avg[i].frame_size);
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}
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denoiser->yv12_mc_running_avg.flags = 0;
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if (vp8_yv12_alloc_frame_buffer(&(denoiser->yv12_mc_running_avg), width,
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height, VP8BORDERINPIXELS) < 0)
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{
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vp8_denoiser_free(denoiser);
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return 1;
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}
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vpx_memset(denoiser->yv12_mc_running_avg.buffer_alloc, 0,
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denoiser->yv12_mc_running_avg.frame_size);
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denoiser->denoise_state = vpx_calloc((num_mb_rows * num_mb_cols), 1);
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vpx_memset(denoiser->denoise_state, 0, (num_mb_rows * num_mb_cols));
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return 0;
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}
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void vp8_denoiser_free(VP8_DENOISER *denoiser)
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{
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int i;
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assert(denoiser);
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for (i = 0; i < MAX_REF_FRAMES ; i++)
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{
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vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_running_avg[i]);
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}
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vp8_yv12_de_alloc_frame_buffer(&denoiser->yv12_mc_running_avg);
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}
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void vp8_denoiser_denoise_mb(VP8_DENOISER *denoiser,
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MACROBLOCK *x,
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unsigned int best_sse,
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unsigned int zero_mv_sse,
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int recon_yoffset,
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int recon_uvoffset,
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loop_filter_info_n *lfi_n,
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int mb_row,
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int mb_col,
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int block_index)
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{
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int mv_row;
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int mv_col;
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unsigned int motion_magnitude2;
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unsigned int sse_thresh;
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int sse_diff_thresh = 0;
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// Spatial loop filter: only applied selectively based on
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// temporal filter state of block relative to top/left neighbors.
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int apply_spatial_loop_filter = 1;
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MV_REFERENCE_FRAME frame = x->best_reference_frame;
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MV_REFERENCE_FRAME zero_frame = x->best_zeromv_reference_frame;
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enum vp8_denoiser_decision decision = FILTER_BLOCK;
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if (zero_frame)
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{
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YV12_BUFFER_CONFIG *src = &denoiser->yv12_running_avg[frame];
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YV12_BUFFER_CONFIG *dst = &denoiser->yv12_mc_running_avg;
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YV12_BUFFER_CONFIG saved_pre,saved_dst;
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MB_MODE_INFO saved_mbmi;
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MACROBLOCKD *filter_xd = &x->e_mbd;
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MB_MODE_INFO *mbmi = &filter_xd->mode_info_context->mbmi;
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int sse_diff = zero_mv_sse - best_sse;
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saved_mbmi = *mbmi;
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/* Use the best MV for the compensation. */
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mbmi->ref_frame = x->best_reference_frame;
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mbmi->mode = x->best_sse_inter_mode;
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mbmi->mv = x->best_sse_mv;
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mbmi->need_to_clamp_mvs = x->need_to_clamp_best_mvs;
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mv_col = x->best_sse_mv.as_mv.col;
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mv_row = x->best_sse_mv.as_mv.row;
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// Bias to zero_mv if small amount of motion.
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// Note sse_diff_thresh is intialized to zero, so this ensures
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// we will always choose zero_mv for denoising if
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// zero_mv_see <= best_sse (i.e., sse_diff <= 0).
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if ((unsigned int)(mv_row * mv_row + mv_col * mv_col)
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<= NOISE_MOTION_THRESHOLD)
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sse_diff_thresh = (int)SSE_DIFF_THRESHOLD;
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if (frame == INTRA_FRAME ||
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sse_diff <= sse_diff_thresh)
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{
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/*
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* Handle intra blocks as referring to last frame with zero motion
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* and let the absolute pixel difference affect the filter factor.
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* Also consider small amount of motion as being random walk due
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* to noise, if it doesn't mean that we get a much bigger error.
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* Note that any changes to the mode info only affects the
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* denoising.
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*/
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mbmi->ref_frame =
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x->best_zeromv_reference_frame;
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src = &denoiser->yv12_running_avg[zero_frame];
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mbmi->mode = ZEROMV;
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mbmi->mv.as_int = 0;
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x->best_sse_inter_mode = ZEROMV;
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x->best_sse_mv.as_int = 0;
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best_sse = zero_mv_sse;
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}
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saved_pre = filter_xd->pre;
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saved_dst = filter_xd->dst;
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/* Compensate the running average. */
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filter_xd->pre.y_buffer = src->y_buffer + recon_yoffset;
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filter_xd->pre.u_buffer = src->u_buffer + recon_uvoffset;
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filter_xd->pre.v_buffer = src->v_buffer + recon_uvoffset;
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/* Write the compensated running average to the destination buffer. */
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filter_xd->dst.y_buffer = dst->y_buffer + recon_yoffset;
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filter_xd->dst.u_buffer = dst->u_buffer + recon_uvoffset;
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filter_xd->dst.v_buffer = dst->v_buffer + recon_uvoffset;
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if (!x->skip)
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{
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vp8_build_inter_predictors_mb(filter_xd);
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}
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else
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{
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vp8_build_inter16x16_predictors_mb(filter_xd,
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filter_xd->dst.y_buffer,
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filter_xd->dst.u_buffer,
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filter_xd->dst.v_buffer,
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filter_xd->dst.y_stride,
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filter_xd->dst.uv_stride);
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}
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filter_xd->pre = saved_pre;
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filter_xd->dst = saved_dst;
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*mbmi = saved_mbmi;
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}
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mv_row = x->best_sse_mv.as_mv.row;
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mv_col = x->best_sse_mv.as_mv.col;
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motion_magnitude2 = mv_row * mv_row + mv_col * mv_col;
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sse_thresh = SSE_THRESHOLD;
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if (x->increase_denoising) sse_thresh = SSE_THRESHOLD_HIGH;
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if (best_sse > sse_thresh || motion_magnitude2
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> 8 * NOISE_MOTION_THRESHOLD)
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{
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decision = COPY_BLOCK;
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}
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if (decision == FILTER_BLOCK)
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{
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unsigned char *mc_running_avg_y =
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denoiser->yv12_mc_running_avg.y_buffer + recon_yoffset;
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int mc_avg_y_stride = denoiser->yv12_mc_running_avg.y_stride;
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unsigned char *running_avg_y =
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denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset;
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int avg_y_stride = denoiser->yv12_running_avg[INTRA_FRAME].y_stride;
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/* Filter. */
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decision = vp8_denoiser_filter(mc_running_avg_y, mc_avg_y_stride,
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running_avg_y, avg_y_stride,
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x->thismb, 16, motion_magnitude2,
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x->increase_denoising);
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denoiser->denoise_state[block_index] = motion_magnitude2 > 0 ?
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kFilterNonZeroMV : kFilterZeroMV;
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}
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if (decision == COPY_BLOCK)
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{
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/* No filtering of this block; it differs too much from the predictor,
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* or the motion vector magnitude is considered too big.
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*/
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vp8_copy_mem16x16(
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x->thismb, 16,
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denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset,
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denoiser->yv12_running_avg[INTRA_FRAME].y_stride);
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denoiser->denoise_state[block_index] = kNoFilter;
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}
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// Option to selectively deblock the denoised signal.
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if (apply_spatial_loop_filter) {
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loop_filter_info lfi;
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int apply_filter_col = 0;
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int apply_filter_row = 0;
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int apply_filter = 0;
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int y_stride = denoiser->yv12_running_avg[INTRA_FRAME].y_stride;
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int uv_stride =denoiser->yv12_running_avg[INTRA_FRAME].uv_stride;
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// Fix filter level to some nominal value for now.
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int filter_level = 32;
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int hev_index = lfi_n->hev_thr_lut[INTER_FRAME][filter_level];
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lfi.mblim = lfi_n->mblim[filter_level];
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lfi.blim = lfi_n->blim[filter_level];
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lfi.lim = lfi_n->lim[filter_level];
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lfi.hev_thr = lfi_n->hev_thr[hev_index];
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// Apply filter if there is a difference in the denoiser filter state
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// between the current and left/top block, or if non-zero motion vector
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// is used for the motion-compensated filtering.
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if (mb_col > 0) {
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apply_filter_col = !((denoiser->denoise_state[block_index] ==
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denoiser->denoise_state[block_index - 1]) &&
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denoiser->denoise_state[block_index] != kFilterNonZeroMV);
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if (apply_filter_col) {
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// Filter left vertical edge.
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apply_filter = 1;
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vp8_loop_filter_mbv(
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denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset,
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NULL, NULL, y_stride, uv_stride, &lfi);
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}
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}
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if (mb_row > 0) {
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apply_filter_row = !((denoiser->denoise_state[block_index] ==
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denoiser->denoise_state[block_index - denoiser->num_mb_cols]) &&
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denoiser->denoise_state[block_index] != kFilterNonZeroMV);
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if (apply_filter_row) {
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// Filter top horizontal edge.
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apply_filter = 1;
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vp8_loop_filter_mbh(
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denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset,
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NULL, NULL, y_stride, uv_stride, &lfi);
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}
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}
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if (apply_filter) {
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// Update the signal block |x|. Pixel changes are only to top and/or
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// left boundary pixels: can we avoid full block copy here.
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vp8_copy_mem16x16(
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denoiser->yv12_running_avg[INTRA_FRAME].y_buffer + recon_yoffset,
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y_stride, x->thismb, 16);
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}
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}
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}
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