aom/av1/common/od_dering.c

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16 KiB
C

/*
* Copyright (c) 2016, Alliance for Open Media. All rights reserved
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/
#include <math.h>
#include <stdlib.h>
#ifdef HAVE_CONFIG_H
#include "./config.h"
#endif
#include "./aom_dsp_rtcd.h"
#include "./av1_rtcd.h"
#include "./cdef.h"
/* Generated from gen_filter_tables.c. */
const int OD_DIRECTION_OFFSETS_TABLE[8][3] = {
{ -1 * OD_FILT_BSTRIDE + 1, -2 * OD_FILT_BSTRIDE + 2,
-3 * OD_FILT_BSTRIDE + 3 },
{ 0 * OD_FILT_BSTRIDE + 1, -1 * OD_FILT_BSTRIDE + 2,
-1 * OD_FILT_BSTRIDE + 3 },
{ 0 * OD_FILT_BSTRIDE + 1, 0 * OD_FILT_BSTRIDE + 2, 0 * OD_FILT_BSTRIDE + 3 },
{ 0 * OD_FILT_BSTRIDE + 1, 1 * OD_FILT_BSTRIDE + 2, 1 * OD_FILT_BSTRIDE + 3 },
{ 1 * OD_FILT_BSTRIDE + 1, 2 * OD_FILT_BSTRIDE + 2, 3 * OD_FILT_BSTRIDE + 3 },
{ 1 * OD_FILT_BSTRIDE + 0, 2 * OD_FILT_BSTRIDE + 1, 3 * OD_FILT_BSTRIDE + 1 },
{ 1 * OD_FILT_BSTRIDE + 0, 2 * OD_FILT_BSTRIDE + 0, 3 * OD_FILT_BSTRIDE + 0 },
{ 1 * OD_FILT_BSTRIDE + 0, 2 * OD_FILT_BSTRIDE - 1, 3 * OD_FILT_BSTRIDE - 1 },
};
/* Detect direction. 0 means 45-degree up-right, 2 is horizontal, and so on.
The search minimizes the weighted variance along all the lines in a
particular direction, i.e. the squared error between the input and a
"predicted" block where each pixel is replaced by the average along a line
in a particular direction. Since each direction have the same sum(x^2) term,
that term is never computed. See Section 2, step 2, of:
http://jmvalin.ca/notes/intra_paint.pdf */
int od_dir_find8_c(const uint16_t *img, int stride, int32_t *var,
int coeff_shift) {
int i;
int32_t cost[8] = { 0 };
int partial[8][15] = { { 0 } };
int32_t best_cost = 0;
int best_dir = 0;
/* Instead of dividing by n between 2 and 8, we multiply by 3*5*7*8/n.
The output is then 840 times larger, but we don't care for finding
the max. */
static const int div_table[] = { 0, 840, 420, 280, 210, 168, 140, 120, 105 };
for (i = 0; i < 8; i++) {
int j;
for (j = 0; j < 8; j++) {
int x;
/* We subtract 128 here to reduce the maximum range of the squared
partial sums. */
x = (img[i * stride + j] >> coeff_shift) - 128;
partial[0][i + j] += x;
partial[1][i + j / 2] += x;
partial[2][i] += x;
partial[3][3 + i - j / 2] += x;
partial[4][7 + i - j] += x;
partial[5][3 - i / 2 + j] += x;
partial[6][j] += x;
partial[7][i / 2 + j] += x;
}
}
for (i = 0; i < 8; i++) {
cost[2] += partial[2][i] * partial[2][i];
cost[6] += partial[6][i] * partial[6][i];
}
cost[2] *= div_table[8];
cost[6] *= div_table[8];
for (i = 0; i < 7; i++) {
cost[0] += (partial[0][i] * partial[0][i] +
partial[0][14 - i] * partial[0][14 - i]) *
div_table[i + 1];
cost[4] += (partial[4][i] * partial[4][i] +
partial[4][14 - i] * partial[4][14 - i]) *
div_table[i + 1];
}
cost[0] += partial[0][7] * partial[0][7] * div_table[8];
cost[4] += partial[4][7] * partial[4][7] * div_table[8];
for (i = 1; i < 8; i += 2) {
int j;
for (j = 0; j < 4 + 1; j++) {
cost[i] += partial[i][3 + j] * partial[i][3 + j];
}
cost[i] *= div_table[8];
for (j = 0; j < 4 - 1; j++) {
cost[i] += (partial[i][j] * partial[i][j] +
partial[i][10 - j] * partial[i][10 - j]) *
div_table[2 * j + 2];
}
}
for (i = 0; i < 8; i++) {
if (cost[i] > best_cost) {
best_cost = cost[i];
best_dir = i;
}
}
/* Difference between the optimal variance and the variance along the
orthogonal direction. Again, the sum(x^2) terms cancel out. */
*var = best_cost - cost[(best_dir + 4) & 7];
/* We'd normally divide by 840, but dividing by 1024 is close enough
for what we're going to do with this. */
*var >>= 10;
return best_dir;
}
/* Smooth in the direction detected. */
void od_filter_dering_direction_8x8_c(uint16_t *y, int ystride,
const uint16_t *in, int threshold,
int dir, int damping) {
int i;
int j;
int k;
static const int taps[3] = { 3, 2, 1 };
for (i = 0; i < 8; i++) {
for (j = 0; j < 8; j++) {
int16_t sum;
int16_t xx;
int16_t yy;
xx = in[i * OD_FILT_BSTRIDE + j];
sum = 0;
for (k = 0; k < 3; k++) {
int16_t p0;
int16_t p1;
p0 = in[i * OD_FILT_BSTRIDE + j + OD_DIRECTION_OFFSETS_TABLE[dir][k]] -
xx;
p1 = in[i * OD_FILT_BSTRIDE + j - OD_DIRECTION_OFFSETS_TABLE[dir][k]] -
xx;
sum += taps[k] * constrain(p0, threshold, damping);
sum += taps[k] * constrain(p1, threshold, damping);
}
sum = (sum + 8) >> 4;
yy = xx + sum;
y[i * ystride + j] = yy;
}
}
}
/* Smooth in the direction detected. */
void od_filter_dering_direction_4x4_c(uint16_t *y, int ystride,
const uint16_t *in, int threshold,
int dir, int damping) {
int i;
int j;
int k;
static const int taps[2] = { 4, 1 };
for (i = 0; i < 4; i++) {
for (j = 0; j < 4; j++) {
int16_t sum;
int16_t xx;
int16_t yy;
xx = in[i * OD_FILT_BSTRIDE + j];
sum = 0;
for (k = 0; k < 2; k++) {
int16_t p0;
int16_t p1;
p0 = in[i * OD_FILT_BSTRIDE + j + OD_DIRECTION_OFFSETS_TABLE[dir][k]] -
xx;
p1 = in[i * OD_FILT_BSTRIDE + j - OD_DIRECTION_OFFSETS_TABLE[dir][k]] -
xx;
sum += taps[k] * constrain(p0, threshold, damping);
sum += taps[k] * constrain(p1, threshold, damping);
}
sum = (sum + 8) >> 4;
yy = xx + sum;
y[i * ystride + j] = yy;
}
}
}
/* This table approximates x^0.16 with the index being log2(x). It is clamped
to [-.5, 3]. The table is computed as:
round(256*min(3, max(.5, 1.08*(sqrt(2)*2.^([0:17]+8)/256/256).^.16))) */
static const int16_t OD_THRESH_TABLE_Q8[18] = {
128, 134, 150, 168, 188, 210, 234, 262, 292,
327, 365, 408, 455, 509, 569, 635, 710, 768,
};
/* Compute deringing filter threshold for an 8x8 block based on the
directional variance difference. A high variance difference means that we
have a highly directional pattern (e.g. a high contrast edge), so we can
apply more deringing. A low variance means that we either have a low
contrast edge, or a non-directional texture, so we want to be careful not
to blur. */
static INLINE int od_adjust_thresh(int threshold, int32_t var) {
int v1;
/* We use the variance of 8x8 blocks to adjust the threshold. */
v1 = OD_MINI(32767, var >> 6);
return (threshold * OD_THRESH_TABLE_Q8[OD_ILOG(v1)] + 128) >> 8;
}
void copy_8x8_16bit_to_16bit_c(uint16_t *dst, int dstride, const uint16_t *src,
int sstride) {
int i, j;
for (i = 0; i < 8; i++)
for (j = 0; j < 8; j++) dst[i * dstride + j] = src[i * sstride + j];
}
void copy_4x4_16bit_to_16bit_c(uint16_t *dst, int dstride, const uint16_t *src,
int sstride) {
int i, j;
for (i = 0; i < 4; i++)
for (j = 0; j < 4; j++) dst[i * dstride + j] = src[i * sstride + j];
}
void copy_dering_16bit_to_16bit(uint16_t *dst, int dstride, uint16_t *src,
dering_list *dlist, int dering_count,
int bsize) {
int bi, bx, by;
if (bsize == BLOCK_8X8) {
for (bi = 0; bi < dering_count; bi++) {
by = dlist[bi].by;
bx = dlist[bi].bx;
copy_8x8_16bit_to_16bit(&dst[(by << 3) * dstride + (bx << 3)], dstride,
&src[bi << (3 + 3)], 8);
}
} else if (bsize == BLOCK_4X8) {
for (bi = 0; bi < dering_count; bi++) {
by = dlist[bi].by;
bx = dlist[bi].bx;
copy_4x4_16bit_to_16bit(&dst[(by << 3) * dstride + (bx << 2)], dstride,
&src[bi << (3 + 2)], 4);
copy_4x4_16bit_to_16bit(&dst[((by << 3) + 4) * dstride + (bx << 2)],
dstride, &src[(bi << (3 + 2)) + 4 * 4], 4);
}
} else if (bsize == BLOCK_8X4) {
for (bi = 0; bi < dering_count; bi++) {
by = dlist[bi].by;
bx = dlist[bi].bx;
copy_4x4_16bit_to_16bit(&dst[(by << 2) * dstride + (bx << 3)], dstride,
&src[bi << (2 + 3)], 8);
copy_4x4_16bit_to_16bit(&dst[(by << 2) * dstride + (bx << 3) + 4],
dstride, &src[(bi << (2 + 3)) + 4], 8);
}
} else {
assert(bsize == BLOCK_4X4);
for (bi = 0; bi < dering_count; bi++) {
by = dlist[bi].by;
bx = dlist[bi].bx;
copy_4x4_16bit_to_16bit(&dst[(by << 2) * dstride + (bx << 2)], dstride,
&src[bi << (2 + 2)], 4);
}
}
}
void copy_8x8_16bit_to_8bit_c(uint8_t *dst, int dstride, const uint16_t *src,
int sstride) {
int i, j;
for (i = 0; i < 8; i++)
for (j = 0; j < 8; j++)
dst[i * dstride + j] = (uint8_t)src[i * sstride + j];
}
void copy_4x4_16bit_to_8bit_c(uint8_t *dst, int dstride, const uint16_t *src,
int sstride) {
int i, j;
for (i = 0; i < 4; i++)
for (j = 0; j < 4; j++)
dst[i * dstride + j] = (uint8_t)src[i * sstride + j];
}
static void copy_dering_16bit_to_8bit(uint8_t *dst, int dstride,
const uint16_t *src, dering_list *dlist,
int dering_count, int bsize) {
int bi, bx, by;
if (bsize == BLOCK_8X8) {
for (bi = 0; bi < dering_count; bi++) {
by = dlist[bi].by;
bx = dlist[bi].bx;
copy_8x8_16bit_to_8bit(&dst[(by << 3) * dstride + (bx << 3)], dstride,
&src[bi << (3 + 3)], 8);
}
} else if (bsize == BLOCK_4X8) {
for (bi = 0; bi < dering_count; bi++) {
by = dlist[bi].by;
bx = dlist[bi].bx;
copy_4x4_16bit_to_8bit(&dst[(by << 3) * dstride + (bx << 2)], dstride,
&src[bi << (3 + 2)], 4);
copy_4x4_16bit_to_8bit(&dst[((by << 3) + 4) * dstride + (bx << 2)],
dstride, &src[(bi << (3 + 2)) + 4 * 4], 4);
}
} else if (bsize == BLOCK_8X4) {
for (bi = 0; bi < dering_count; bi++) {
by = dlist[bi].by;
bx = dlist[bi].bx;
copy_4x4_16bit_to_8bit(&dst[(by << 2) * dstride + (bx << 3)], dstride,
&src[bi << (2 + 3)], 8);
copy_4x4_16bit_to_8bit(&dst[(by << 2) * dstride + (bx << 3) + 4], dstride,
&src[(bi << (2 + 3)) + 4], 8);
}
} else {
assert(bsize == BLOCK_4X4);
for (bi = 0; bi < dering_count; bi++) {
by = dlist[bi].by;
bx = dlist[bi].bx;
copy_4x4_16bit_to_8bit(&dst[(by << 2) * dstride + (bx << 2)], dstride,
&src[bi << (2 * 2)], 4);
}
}
}
int get_filter_skip(int level) {
int filter_skip = level & 1;
if (level == 1) filter_skip = 0;
return filter_skip;
}
void od_dering(uint8_t *dst, int dstride, uint16_t *y, uint16_t *in, int xdec,
int ydec, int dir[OD_DERING_NBLOCKS][OD_DERING_NBLOCKS],
int *dirinit, int var[OD_DERING_NBLOCKS][OD_DERING_NBLOCKS],
int pli, dering_list *dlist, int dering_count, int level,
int clpf_strength, int clpf_damping, int coeff_shift,
int skip_dering, int hbd) {
int bi;
int bx;
int by;
int bsize, bsizex, bsizey;
int threshold = (level >> 1) << coeff_shift;
int dering_damping = 5 + !pli + coeff_shift;
int filter_skip = get_filter_skip(level);
if (level == 1) threshold = 31 << coeff_shift;
od_filter_dering_direction_func filter_dering_direction[] = {
od_filter_dering_direction_4x4, od_filter_dering_direction_8x8
};
clpf_damping += coeff_shift;
bsize =
ydec ? (xdec ? BLOCK_4X4 : BLOCK_8X4) : (xdec ? BLOCK_4X8 : BLOCK_8X8);
bsizex = 3 - xdec;
bsizey = 3 - ydec;
if (!skip_dering) {
if (pli == 0) {
if (!dirinit || !*dirinit) {
for (bi = 0; bi < dering_count; bi++) {
by = dlist[bi].by;
bx = dlist[bi].bx;
dir[by][bx] =
od_dir_find8(&in[8 * by * OD_FILT_BSTRIDE + 8 * bx],
OD_FILT_BSTRIDE, &var[by][bx], coeff_shift);
}
if (dirinit) *dirinit = 1;
}
}
// Only run dering for non-zero threshold (which is always the case for
// 4:2:2 or 4:4:0). If we don't dering, we still need to eventually write
// something out in y[] later.
if (threshold != 0) {
assert(bsize == BLOCK_8X8 || bsize == BLOCK_4X4);
for (bi = 0; bi < dering_count; bi++) {
int t = !filter_skip && dlist[bi].skip ? 0 : threshold;
by = dlist[bi].by;
bx = dlist[bi].bx;
(filter_dering_direction[bsize == BLOCK_8X8])(
&y[bi << (bsizex + bsizey)], 1 << bsizex,
&in[(by * OD_FILT_BSTRIDE << bsizey) + (bx << bsizex)],
pli ? t : od_adjust_thresh(t, var[by][bx]), dir[by][bx],
dering_damping);
}
}
}
if (clpf_strength) {
if (threshold && !skip_dering)
copy_dering_16bit_to_16bit(in, OD_FILT_BSTRIDE, y, dlist, dering_count,
bsize);
for (bi = 0; bi < dering_count; bi++) {
by = dlist[bi].by;
bx = dlist[bi].bx;
int py = by << bsizey;
int px = bx << bsizex;
if (!filter_skip && dlist[bi].skip) continue;
if (!dst || hbd) {
// 16 bit destination if high bitdepth or 8 bit destination not given
(!threshold || (dir[by][bx] < 4 && dir[by][bx]) ? aom_clpf_block_hbd
: aom_clpf_hblock_hbd)(
dst ? (uint16_t *)dst + py * dstride + px
: &y[bi << (bsizex + bsizey)],
in + py * OD_FILT_BSTRIDE + px, dst && hbd ? dstride : 1 << bsizex,
OD_FILT_BSTRIDE, 1 << bsizex, 1 << bsizey,
clpf_strength << coeff_shift, clpf_damping);
} else {
// Do clpf and write the result to an 8 bit destination
(!threshold || (dir[by][bx] < 4 && dir[by][bx]) ? aom_clpf_block
: aom_clpf_hblock)(
dst + py * dstride + px, in + py * OD_FILT_BSTRIDE + px, dstride,
OD_FILT_BSTRIDE, 1 << bsizex, 1 << bsizey,
clpf_strength << coeff_shift, clpf_damping);
}
}
} else if (threshold != 0) {
// No clpf, so copy instead
if (hbd) {
copy_dering_16bit_to_16bit((uint16_t *)dst, dstride, y, dlist,
dering_count, bsize);
} else {
copy_dering_16bit_to_8bit(dst, dstride, y, dlist, dering_count, bsize);
}
} else if (dirinit) {
// If we're here, both dering and clpf are off, and we still haven't written
// anything to y[] yet, so we just copy the input to y[]. This is necessary
// only for av1_cdef_search() and only av1_cdef_search() sets dirinit.
for (bi = 0; bi < dering_count; bi++) {
by = dlist[bi].by;
bx = dlist[bi].bx;
int iy, ix;
// TODO(stemidts/jmvalin): SIMD optimisations
for (iy = 0; iy < 1 << bsizey; iy++)
for (ix = 0; ix < 1 << bsizex; ix++)
y[(bi << (bsizex + bsizey)) + (iy << bsizex) + ix] =
in[((by << bsizey) + iy) * OD_FILT_BSTRIDE + (bx << bsizex) + ix];
}
}
}