339 строки
12 KiB
C
339 строки
12 KiB
C
/*
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* Copyright (c) 2016, Alliance for Open Media. All rights reserved
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*
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* This source code is subject to the terms of the BSD 2 Clause License and
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* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
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* was not distributed with this source code in the LICENSE file, you can
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* obtain it at www.aomedia.org/license/software. If the Alliance for Open
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* Media Patent License 1.0 was not distributed with this source code in the
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* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <stdlib.h>
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#include <math.h>
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#include "dering.h"
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const od_dering_opt_vtbl OD_DERING_VTBL_C = {
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{od_filter_dering_direction_4x4_c, od_filter_dering_direction_8x8_c},
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{od_filter_dering_orthogonal_4x4_c, od_filter_dering_orthogonal_8x8_c}
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};
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/* Generated from gen_filter_tables.c. */
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const int OD_DIRECTION_OFFSETS_TABLE[8][3] = {
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{-1*OD_FILT_BSTRIDE + 1, -2*OD_FILT_BSTRIDE + 2, -3*OD_FILT_BSTRIDE + 3 },
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{ 0*OD_FILT_BSTRIDE + 1, -1*OD_FILT_BSTRIDE + 2, -1*OD_FILT_BSTRIDE + 3 },
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{ 0*OD_FILT_BSTRIDE + 1, 0*OD_FILT_BSTRIDE + 2, 0*OD_FILT_BSTRIDE + 3 },
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{ 0*OD_FILT_BSTRIDE + 1, 1*OD_FILT_BSTRIDE + 2, 1*OD_FILT_BSTRIDE + 3 },
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{ 1*OD_FILT_BSTRIDE + 1, 2*OD_FILT_BSTRIDE + 2, 3*OD_FILT_BSTRIDE + 3 },
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{ 1*OD_FILT_BSTRIDE + 0, 2*OD_FILT_BSTRIDE + 1, 3*OD_FILT_BSTRIDE + 1 },
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{ 1*OD_FILT_BSTRIDE + 0, 2*OD_FILT_BSTRIDE + 0, 3*OD_FILT_BSTRIDE + 0 },
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{ 1*OD_FILT_BSTRIDE + 0, 2*OD_FILT_BSTRIDE - 1, 3*OD_FILT_BSTRIDE - 1 },
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};
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const double OD_DERING_GAIN_TABLE[OD_DERING_LEVELS] = {
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0, 0.5, 0.707, 1, 1.41, 2
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};
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/* Detect direction. 0 means 45-degree up-right, 2 is horizontal, and so on.
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The search minimizes the weighted variance along all the lines in a
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particular direction, i.e. the squared error between the input and a
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"predicted" block where each pixel is replaced by the average along a line
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in a particular direction. Since each direction have the same sum(x^2) term,
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that term is never computed. See Section 2, step 2, of:
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http://jmvalin.ca/notes/intra_paint.pdf */
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static int od_dir_find8(const od_dering_in *img, int stride, int32_t *var,
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int coeff_shift) {
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int i;
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int32_t cost[8] = {0};
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int partial[8][15] = {{0}};
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int32_t best_cost = 0;
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int best_dir = 0;
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/* Instead of dividing by n between 2 and 8, we multiply by 3*5*7*8/n.
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The output is then 840 times larger, but we don't care for finding
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the max. */
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static const int div_table[] = {0, 840, 420, 280, 210, 168, 140, 120, 105};
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for (i = 0; i < 8; i++) {
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int j;
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for (j = 0; j < 8; j++) {
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int x;
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/* We subtract 128 here to reduce the maximum range of the squared
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partial sums. */
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x = (img[i*stride + j] >> coeff_shift) - 128;
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partial[0][i + j] += x;
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partial[1][i + j/2] += x;
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partial[2][i] += x;
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partial[3][3 + i - j/2] += x;
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partial[4][7 + i - j] += x;
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partial[5][3 - i/2 + j] += x;
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partial[6][j] += x;
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partial[7][i/2 + j] += x;
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}
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}
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for (i = 0; i < 8; i++) {
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cost[2] += partial[2][i]*partial[2][i];
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cost[6] += partial[6][i]*partial[6][i];
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}
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cost[2] *= div_table[8];
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cost[6] *= div_table[8];
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for (i = 0; i < 7; i++) {
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cost[0] += (partial[0][i]*partial[0][i]
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+ partial[0][14 - i]*partial[0][14 - i])*div_table[i + 1];
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cost[4] += (partial[4][i]*partial[4][i]
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+ partial[4][14 - i]*partial[4][14 - i])*div_table[i + 1];
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}
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cost[0] += partial[0][7]*partial[0][7]*div_table[8];
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cost[4] += partial[4][7]*partial[4][7]*div_table[8];
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for (i = 1; i < 8; i += 2) {
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int j;
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for (j = 0; j < 4 + 1; j++) {
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cost[i] += partial[i][3 + j]*partial[i][3 + j];
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}
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cost[i] *= div_table[8];
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for (j = 0; j < 4 - 1; j++) {
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cost[i] += (partial[i][j]*partial[i][j]
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+ partial[i][10 - j]*partial[i][10 - j])*div_table[2*j + 2];
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}
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}
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for (i = 0; i < 8; i++) {
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if (cost[i] > best_cost) {
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best_cost = cost[i];
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best_dir = i;
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}
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}
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/* Difference between the optimal variance and the variance along the
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orthogonal direction. Again, the sum(x^2) terms cancel out. */
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*var = best_cost - cost[(best_dir + 4) & 7];
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/* We'd normally divide by 840, but dividing by 1024 is close enough
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for what we're going to do with this. */
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*var >>= 10;
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return best_dir;
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}
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#define OD_DERING_VERY_LARGE (30000)
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#define OD_DERING_INBUF_SIZE ((OD_BSIZE_MAX + 2*OD_FILT_BORDER)*\
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(OD_BSIZE_MAX + 2*OD_FILT_BORDER))
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/* Smooth in the direction detected. */
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void od_filter_dering_direction_c(int16_t *y, int ystride, const int16_t *in,
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int ln, int threshold, int dir) {
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int i;
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int j;
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int k;
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static const int taps[3] = {3, 2, 1};
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for (i = 0; i < 1 << ln; i++) {
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for (j = 0; j < 1 << ln; j++) {
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int16_t sum;
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int16_t xx;
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int16_t yy;
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xx = in[i*OD_FILT_BSTRIDE + j];
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sum= 0;
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for (k = 0; k < 3; k++) {
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int16_t p0;
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int16_t p1;
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p0 = in[i*OD_FILT_BSTRIDE + j + OD_DIRECTION_OFFSETS_TABLE[dir][k]]
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- xx;
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p1 = in[i*OD_FILT_BSTRIDE + j - OD_DIRECTION_OFFSETS_TABLE[dir][k]]
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- xx;
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if (abs(p0) < threshold) sum += taps[k]*p0;
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if (abs(p1) < threshold) sum += taps[k]*p1;
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}
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yy = xx + ((sum + 8) >> 4);
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y[i*ystride + j] = yy;
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}
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}
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}
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void od_filter_dering_direction_4x4_c(int16_t *y, int ystride,
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const int16_t *in, int threshold, int dir) {
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od_filter_dering_direction_c(y, ystride, in, 2, threshold, dir);
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}
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void od_filter_dering_direction_8x8_c(int16_t *y, int ystride,
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const int16_t *in, int threshold, int dir) {
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od_filter_dering_direction_c(y, ystride, in, 3, threshold, dir);
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}
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/* Smooth in the direction orthogonal to what was detected. */
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void od_filter_dering_orthogonal_c(int16_t *y, int ystride, const int16_t *in,
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const od_dering_in *x, int xstride, int ln, int threshold, int dir) {
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int i;
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int j;
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int offset;
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if (dir > 0 && dir < 4) offset = OD_FILT_BSTRIDE;
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else offset = 1;
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for (i = 0; i < 1 << ln; i++) {
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for (j = 0; j < 1 << ln; j++) {
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int16_t athresh;
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int16_t yy;
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int16_t sum;
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int16_t p;
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/* Deringing orthogonal to the direction uses a tighter threshold
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because we want to be conservative. We've presumably already
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achieved some deringing, so the amount of change is expected
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to be low. Also, since we might be filtering across an edge, we
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want to make sure not to blur it. That being said, we might want
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to be a little bit more aggressive on pure horizontal/vertical
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since the ringing there tends to be directional, so it doesn't
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get removed by the directional filtering. */
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athresh = OD_MINI(threshold, threshold/3
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+ abs(in[i*OD_FILT_BSTRIDE + j] - x[i*xstride + j]));
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yy = in[i*OD_FILT_BSTRIDE + j];
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sum = 0;
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p = in[i*OD_FILT_BSTRIDE + j + offset] - yy;
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if (abs(p) < athresh) sum += p;
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p = in[i*OD_FILT_BSTRIDE + j - offset] - yy;
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if (abs(p) < athresh) sum += p;
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p = in[i*OD_FILT_BSTRIDE + j + 2*offset] - yy;
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if (abs(p) < athresh) sum += p;
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p = in[i*OD_FILT_BSTRIDE + j - 2*offset] - yy;
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if (abs(p) < athresh) sum += p;
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y[i*ystride + j] = yy + ((3*sum + 8) >> 4);
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}
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}
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}
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void od_filter_dering_orthogonal_4x4_c(int16_t *y, int ystride,
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const int16_t *in, const od_dering_in *x, int xstride, int threshold,
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int dir) {
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od_filter_dering_orthogonal_c(y, ystride, in, x, xstride, 2, threshold, dir);
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}
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void od_filter_dering_orthogonal_8x8_c(int16_t *y, int ystride,
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const int16_t *in, const od_dering_in *x, int xstride, int threshold,
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int dir) {
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od_filter_dering_orthogonal_c(y, ystride, in, x, xstride, 3, threshold, dir);
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}
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/* This table approximates x^0.16 with the index being log2(x). It is clamped
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to [-.5, 3]. The table is computed as:
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round(256*min(3, max(.5, 1.08*(sqrt(2)*2.^([0:17]+8)/256/256).^.16))) */
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static const int16_t OD_THRESH_TABLE_Q8[18] = {
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128, 134, 150, 168, 188, 210, 234, 262,
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292, 327, 365, 408, 455, 509, 569, 635,
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710, 768,
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};
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/* Compute deringing filter threshold for each 8x8 block based on the
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directional variance difference. A high variance difference means that we
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have a highly directional pattern (e.g. a high contrast edge), so we can
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apply more deringing. A low variance means that we either have a low
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contrast edge, or a non-directional texture, so we want to be careful not
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to blur. */
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static void od_compute_thresh(int thresh[OD_DERING_NBLOCKS][OD_DERING_NBLOCKS],
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int threshold, int32_t var[OD_DERING_NBLOCKS][OD_DERING_NBLOCKS],
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int nhb, int nvb) {
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int bx;
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int by;
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for (by = 0; by < nvb; by++) {
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for (bx = 0; bx < nhb; bx++) {
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int v1;
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/* We use the variance of 8x8 blocks to adjust the threshold. */
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v1 = OD_MINI(32767, var[by][bx] >> 6);
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thresh[by][bx] = (threshold*OD_THRESH_TABLE_Q8[OD_ILOG(v1)] + 128) >> 8;
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}
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}
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}
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void od_dering(const od_dering_opt_vtbl *vtbl, int16_t *y, int ystride,
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const od_dering_in *x, int xstride, int nhb, int nvb, int sbx, int sby,
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int nhsb, int nvsb, int xdec, int dir[OD_DERING_NBLOCKS][OD_DERING_NBLOCKS],
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int pli, unsigned char *bskip, int skip_stride, int threshold, int overlap,
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int coeff_shift) {
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int i;
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int j;
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int bx;
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int by;
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int16_t inbuf[OD_DERING_INBUF_SIZE];
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int16_t *in;
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int bsize;
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int32_t var[OD_DERING_NBLOCKS][OD_DERING_NBLOCKS];
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int thresh[OD_DERING_NBLOCKS][OD_DERING_NBLOCKS];
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bsize = 3 - xdec;
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in = inbuf + OD_FILT_BORDER*OD_FILT_BSTRIDE + OD_FILT_BORDER;
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/* We avoid filtering the pixels for which some of the pixels to average
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are outside the frame. We could change the filter instead, but it would
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add special cases for any future vectorization. */
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for (i = 0; i < OD_DERING_INBUF_SIZE; i++) inbuf[i] = OD_DERING_VERY_LARGE;
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for (i = -OD_FILT_BORDER*(sby != 0); i < (nvb << bsize)
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+ OD_FILT_BORDER*(sby != nvsb - 1); i++) {
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for (j = -OD_FILT_BORDER*(sbx != 0); j < (nhb << bsize)
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+ OD_FILT_BORDER*(sbx != nhsb - 1); j++) {
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in[i*OD_FILT_BSTRIDE + j] = x[i*xstride + j];
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}
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}
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if (pli == 0) {
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for (by = 0; by < nvb; by++) {
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for (bx = 0; bx < nhb; bx++) {
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dir[by][bx] = od_dir_find8(&x[8*by*xstride + 8*bx], xstride,
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&var[by][bx], coeff_shift);
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}
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}
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od_compute_thresh(thresh, threshold, var, nhb, nvb);
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}
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else {
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for (by = 0; by < nvb; by++) {
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for (bx = 0; bx < nhb; bx++) {
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thresh[by][bx] = threshold;
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}
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}
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}
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for (by = 0; by < nvb; by++) {
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for (bx = 0; bx < nhb; bx++) {
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int skip;
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# if defined(DAALA_ODINTRIN)
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int xstart;
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int ystart;
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int xend;
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int yend;
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xstart = ystart = 0;
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xend = yend = (2 >> xdec);
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if (overlap) {
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xstart -= (sbx != 0);
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ystart -= (sby != 0);
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xend += (sbx != nhsb - 1);
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yend += (sby != nvsb - 1);
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}
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skip = 1;
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/* We look at whether the current block and its 4x4 surrounding (due to
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lapping) are skipped to avoid filtering the same content multiple
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times. */
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for (i = ystart; i < yend; i++) {
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for (j = xstart; j < xend; j++) {
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skip = skip && bskip[((by << 1 >> xdec) + i)*skip_stride
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+ (bx << 1 >> xdec) + j];
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}
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}
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#else
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(void)overlap;
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skip = bskip[by*skip_stride + bx];
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#endif
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if (skip) thresh[by][bx] = 0;
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}
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}
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for (by = 0; by < nvb; by++) {
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for (bx = 0; bx < nhb; bx++) {
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(vtbl->filter_dering_direction[bsize - OD_LOG_BSIZE0])(
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&y[(by*ystride << bsize) + (bx << bsize)], ystride,
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&in[(by*OD_FILT_BSTRIDE << bsize) + (bx << bsize)],
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thresh[by][bx], dir[by][bx]);
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}
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}
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for (i = 0; i < nvb << bsize; i++) {
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for (j = 0; j < nhb << bsize; j++) {
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in[i*OD_FILT_BSTRIDE + j] = y[i*ystride + j];
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}
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}
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for (by = 0; by < nvb; by++) {
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for (bx = 0; bx < nhb; bx++) {
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(vtbl->filter_dering_orthogonal[bsize - OD_LOG_BSIZE0])(
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&y[(by*ystride << bsize) + (bx << bsize)], ystride,
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&in[(by*OD_FILT_BSTRIDE << bsize) + (bx << bsize)],
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&x[(by*xstride << bsize) + (bx << bsize)], xstride,
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thresh[by][bx], dir[by][bx]);
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}
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}
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}
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