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/*
* Copyright (c) 2023, 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 <arm_neon.h>
#include "config/aom_config.h"
#include "config/av1_rtcd.h"
#include "av1/encoder/encoder.h"
#include "av1/encoder/temporal_filter.h"
#include "aom_dsp/mathutils.h"
#include "aom_dsp/arm/mem_neon.h"
#include "aom_dsp/arm/sum_neon.h"
static INLINE void get_squared_error(
const uint16_t *frame1, const uint32_t stride1, const uint16_t *frame2,
const uint32_t stride2, const uint32_t block_width,
const uint32_t block_height, uint32_t *frame_sse,
const unsigned int dst_stride) {
uint32_t *dst = frame_sse;
uint32_t i = 0;
do {
uint32_t j = 0;
do {
uint16x8_t s = vld1q_u16(frame1 + i * stride1 + j);
uint16x8_t r = vld1q_u16(frame2 + i * stride2 + j);
uint16x8_t abs_diff = vabdq_u16(s, r);
uint32x4_t sse_lo =
vmull_u16(vget_low_u16(abs_diff), vget_low_u16(abs_diff));
uint32x4_t sse_hi =
vmull_u16(vget_high_u16(abs_diff), vget_high_u16(abs_diff));
vst1q_u32(dst + j, sse_lo);
vst1q_u32(dst + j + 4, sse_hi);
j += 8;
} while (j < block_width);
dst += dst_stride;
i++;
} while (i < block_height);
}
static uint32_t sum_kernel5x5_mask_single(const uint32x4_t vsrc[5][2],
const uint32x4_t mask_single) {
uint32x4_t vsums = vmulq_u32(vsrc[0][0], mask_single);
vsums = vmlaq_u32(vsums, vsrc[1][0], mask_single);
vsums = vmlaq_u32(vsums, vsrc[2][0], mask_single);
vsums = vmlaq_u32(vsums, vsrc[3][0], mask_single);
vsums = vmlaq_u32(vsums, vsrc[4][0], mask_single);
return horizontal_add_u32x4(vsums);
}
static uint32x4_t sum_kernel5x5_mask_double(const uint32x4_t vsrc[5][2],
const uint32x4_t mask1,
const uint32x4_t mask2) {
uint32x4_t vsums = vmulq_u32(vsrc[0][0], mask1);
vsums = vmlaq_u32(vsums, vsrc[1][0], mask1);
vsums = vmlaq_u32(vsums, vsrc[2][0], mask1);
vsums = vmlaq_u32(vsums, vsrc[3][0], mask1);
vsums = vmlaq_u32(vsums, vsrc[4][0], mask1);
vsums = vmlaq_u32(vsums, vsrc[0][1], mask2);
vsums = vmlaq_u32(vsums, vsrc[1][1], mask2);
vsums = vmlaq_u32(vsums, vsrc[2][1], mask2);
vsums = vmlaq_u32(vsums, vsrc[3][1], mask2);
vsums = vmlaq_u32(vsums, vsrc[4][1], mask2);
return vsums;
}
static void highbd_apply_temporal_filter(
const uint16_t *frame, const unsigned int stride,
const uint32_t block_width, const uint32_t block_height,
const int *subblock_mses, unsigned int *accumulator, uint16_t *count,
const uint32_t *frame_sse, const uint32_t frame_sse_stride,
const uint32_t *luma_sse_sum, const double inv_num_ref_pixels,
const double decay_factor, const double inv_factor,
const double weight_factor, const double *d_factor, int tf_wgt_calc_lvl,
int bd) {
assert(((block_width == 16) || (block_width == 32)) &&
((block_height == 16) || (block_height == 32)));
uint32_t acc_5x5_neon[BH][BW] = { 0 };
const int half_window = TF_WINDOW_LENGTH >> 1;
uint32x4_t vsrc[5][2] = { 0 };
const uint32x4_t k0000 = vdupq_n_u32(0);
const uint32x4_t k1111 = vdupq_n_u32(1);
const uint32_t k3110_u32[4] = { 0, 1, 1, 3 };
const uint32_t k2111_u32[4] = { 1, 1, 1, 2 };
const uint32_t k1112_u32[4] = { 2, 1, 1, 1 };
const uint32_t k0113_u32[4] = { 3, 1, 1, 0 };
const uint32x4_t k3110 = vld1q_u32(k3110_u32);
const uint32x4_t k2111 = vld1q_u32(k2111_u32);
const uint32x4_t k1112 = vld1q_u32(k1112_u32);
const uint32x4_t k0113 = vld1q_u32(k0113_u32);
uint32x4_t vmask1[4], vmask2[4];
vmask1[0] = k1111;
vmask2[0] = vextq_u32(k1111, k0000, 3);
vmask1[1] = vextq_u32(k0000, k1111, 3);
vmask2[1] = vextq_u32(k1111, k0000, 2);
vmask1[2] = vextq_u32(k0000, k1111, 2);
vmask2[2] = vextq_u32(k1111, k0000, 1);
vmask1[3] = vextq_u32(k0000, k1111, 1);
vmask2[3] = k1111;
uint32_t row = 0;
do {
uint32_t col = 0;
const uint32_t *src = frame_sse + row * frame_sse_stride;
if (row == 0) {
vsrc[2][0] = vld1q_u32(src);
vsrc[3][0] = vld1q_u32(src + frame_sse_stride);
vsrc[4][0] = vld1q_u32(src + 2 * frame_sse_stride);
// First 2 rows of the 5x5 matrix are padded from the 1st.
vsrc[0][0] = vsrc[2][0];
vsrc[1][0] = vsrc[2][0];
} else if (row == 1) {
vsrc[1][0] = vld1q_u32(src - frame_sse_stride);
vsrc[2][0] = vld1q_u32(src);
vsrc[3][0] = vld1q_u32(src + frame_sse_stride);
vsrc[4][0] = vld1q_u32(src + 2 * frame_sse_stride);
// First row of the 5x5 matrix are padded from the 1st.
vsrc[0][0] = vsrc[1][0];
} else if (row == block_height - 2) {
vsrc[0][0] = vld1q_u32(src - 2 * frame_sse_stride);
vsrc[1][0] = vld1q_u32(src - frame_sse_stride);
vsrc[2][0] = vld1q_u32(src);
vsrc[3][0] = vld1q_u32(src + frame_sse_stride);
// Last row of the 5x5 matrix are padded from the one before.
vsrc[4][0] = vsrc[3][0];
} else if (row == block_height - 1) {
vsrc[0][0] = vld1q_u32(src - 2 * frame_sse_stride);
vsrc[1][0] = vld1q_u32(src - frame_sse_stride);
vsrc[2][0] = vld1q_u32(src);
// Last 2 rows of the 5x5 matrix are padded from the 3rd.
vsrc[3][0] = vsrc[2][0];
vsrc[4][0] = vsrc[2][0];
} else {
vsrc[0][0] = vld1q_u32(src - 2 * frame_sse_stride);
vsrc[1][0] = vld1q_u32(src - frame_sse_stride);
vsrc[2][0] = vld1q_u32(src);
vsrc[3][0] = vld1q_u32(src + frame_sse_stride);
vsrc[4][0] = vld1q_u32(src + 2 * frame_sse_stride);
}
acc_5x5_neon[row][0] = sum_kernel5x5_mask_single(vsrc, k0113);
acc_5x5_neon[row][1] = sum_kernel5x5_mask_single(vsrc, k1112);
col += 4;
src += 4;
// Traverse 4 columns at a time
do {
if (row == 0) {
vsrc[2][1] = vld1q_u32(src);
vsrc[3][1] = vld1q_u32(src + frame_sse_stride);
vsrc[4][1] = vld1q_u32(src + 2 * frame_sse_stride);
// First 2 rows of the 5x5 matrix are padded from the 1st.
vsrc[0][1] = vsrc[2][1];
vsrc[1][1] = vsrc[2][1];
} else if (row == 1) {
vsrc[1][1] = vld1q_u32(src - frame_sse_stride);
vsrc[2][1] = vld1q_u32(src);
vsrc[3][1] = vld1q_u32(src + frame_sse_stride);
vsrc[4][1] = vld1q_u32(src + 2 * frame_sse_stride);
// First row of the 5x5 matrix are padded from the 1st.
vsrc[0][1] = vsrc[1][1];
} else if (row == block_height - 2) {
vsrc[0][1] = vld1q_u32(src - 2 * frame_sse_stride);
vsrc[1][1] = vld1q_u32(src - frame_sse_stride);
vsrc[2][1] = vld1q_u32(src);
vsrc[3][1] = vld1q_u32(src + frame_sse_stride);
// Last row of the 5x5 matrix are padded from the one before.
vsrc[4][1] = vsrc[3][1];
} else if (row == block_height - 1) {
vsrc[0][1] = vld1q_u32(src - 2 * frame_sse_stride);
vsrc[1][1] = vld1q_u32(src - frame_sse_stride);
vsrc[2][1] = vld1q_u32(src);
// Last 2 rows of the 5x5 matrix are padded from the 3rd.
vsrc[3][1] = vsrc[2][1];
vsrc[4][1] = vsrc[2][1];
} else {
vsrc[0][1] = vld1q_u32(src - 2 * frame_sse_stride);
vsrc[1][1] = vld1q_u32(src - frame_sse_stride);
vsrc[2][1] = vld1q_u32(src);
vsrc[3][1] = vld1q_u32(src + frame_sse_stride);
vsrc[4][1] = vld1q_u32(src + 2 * frame_sse_stride);
}
uint32x4_t sums[4];
sums[0] = sum_kernel5x5_mask_double(vsrc, vmask1[0], vmask2[0]);
sums[1] = sum_kernel5x5_mask_double(vsrc, vmask1[1], vmask2[1]);
sums[2] = sum_kernel5x5_mask_double(vsrc, vmask1[2], vmask2[2]);
sums[3] = sum_kernel5x5_mask_double(vsrc, vmask1[3], vmask2[3]);
vst1q_u32(&acc_5x5_neon[row][col - half_window],
horizontal_add_4d_u32x4(sums));
vsrc[0][0] = vsrc[0][1];
vsrc[1][0] = vsrc[1][1];
vsrc[2][0] = vsrc[2][1];
vsrc[3][0] = vsrc[3][1];
vsrc[4][0] = vsrc[4][1];
src += 4;
col += 4;
} while (col <= block_width - 4);
acc_5x5_neon[row][col - half_window] =
sum_kernel5x5_mask_single(vsrc, k2111);
acc_5x5_neon[row][col - half_window + 1] =
sum_kernel5x5_mask_single(vsrc, k3110);
row++;
} while (row < block_height);
// Perform filtering.
if (tf_wgt_calc_lvl == 0) {
for (unsigned int i = 0, k = 0; i < block_height; i++) {
for (unsigned int j = 0; j < block_width; j++, k++) {
const int pixel_value = frame[i * stride + j];
// Scale down the difference for high bit depth input.
const uint32_t diff_sse =
(acc_5x5_neon[i][j] + luma_sse_sum[i * BW + j]) >> ((bd - 8) * 2);
const double window_error = diff_sse * inv_num_ref_pixels;
const int subblock_idx =
(i >= block_height / 2) * 2 + (j >= block_width / 2);
const double block_error = (double)subblock_mses[subblock_idx];
const double combined_error =
weight_factor * window_error + block_error * inv_factor;
// Compute filter weight.
double scaled_error =
combined_error * d_factor[subblock_idx] * decay_factor;
scaled_error = AOMMIN(scaled_error, 7);
const int weight = (int)(exp(-scaled_error) * TF_WEIGHT_SCALE);
accumulator[k] += weight * pixel_value;
count[k] += weight;
}
}
} else {
for (unsigned int i = 0, k = 0; i < block_height; i++) {
for (unsigned int j = 0; j < block_width; j++, k++) {
const int pixel_value = frame[i * stride + j];
// Scale down the difference for high bit depth input.
const uint32_t diff_sse =
(acc_5x5_neon[i][j] + luma_sse_sum[i * BW + j]) >> ((bd - 8) * 2);
const double window_error = diff_sse * inv_num_ref_pixels;
const int subblock_idx =
(i >= block_height / 2) * 2 + (j >= block_width / 2);
const double block_error = (double)subblock_mses[subblock_idx];
const double combined_error =
weight_factor * window_error + block_error * inv_factor;
// Compute filter weight.
double scaled_error =
combined_error * d_factor[subblock_idx] * decay_factor;
scaled_error = AOMMIN(scaled_error, 7);
const float fweight =
approx_exp((float)-scaled_error) * TF_WEIGHT_SCALE;
const int weight = iroundpf(fweight);
accumulator[k] += weight * pixel_value;
count[k] += weight;
}
}
}
}
void av1_highbd_apply_temporal_filter_neon(
const YV12_BUFFER_CONFIG *frame_to_filter, const MACROBLOCKD *mbd,
const BLOCK_SIZE block_size, const int mb_row, const int mb_col,
const int num_planes, const double *noise_levels, const MV *subblock_mvs,
const int *subblock_mses, const int q_factor, const int filter_strength,
int tf_wgt_calc_lvl, const uint8_t *pred8, uint32_t *accum,
uint16_t *count) {
const int is_high_bitdepth = frame_to_filter->flags & YV12_FLAG_HIGHBITDEPTH;
assert(TF_WINDOW_LENGTH == 5 && "Only support window length 5 with Neon!");
assert(num_planes >= 1 && num_planes <= MAX_MB_PLANE);
(void)is_high_bitdepth;
assert(is_high_bitdepth);
// Block information.
const int mb_height = block_size_high[block_size];
const int mb_width = block_size_wide[block_size];
// Frame information.
const int frame_height = frame_to_filter->y_crop_height;
const int frame_width = frame_to_filter->y_crop_width;
const int min_frame_size = AOMMIN(frame_height, frame_width);
// Variables to simplify combined error calculation.
const double inv_factor = 1.0 / ((TF_WINDOW_BLOCK_BALANCE_WEIGHT + 1) *
TF_SEARCH_ERROR_NORM_WEIGHT);
const double weight_factor =
(double)TF_WINDOW_BLOCK_BALANCE_WEIGHT * inv_factor;
// Adjust filtering based on q.
// Larger q -> stronger filtering -> larger weight.
// Smaller q -> weaker filtering -> smaller weight.
double q_decay = pow((double)q_factor / TF_Q_DECAY_THRESHOLD, 2);
q_decay = CLIP(q_decay, 1e-5, 1);
if (q_factor >= TF_QINDEX_CUTOFF) {
// Max q_factor is 255, therefore the upper bound of q_decay is 8.
// We do not need a clip here.
q_decay = 0.5 * pow((double)q_factor / 64, 2);
}
// Smaller strength -> smaller filtering weight.
double s_decay = pow((double)filter_strength / TF_STRENGTH_THRESHOLD, 2);
s_decay = CLIP(s_decay, 1e-5, 1);
double d_factor[4] = { 0 };
uint32_t frame_sse[BW * BH] = { 0 };
uint32_t luma_sse_sum[BW * BH] = { 0 };
uint16_t *pred = CONVERT_TO_SHORTPTR(pred8);
for (int subblock_idx = 0; subblock_idx < 4; subblock_idx++) {
// Larger motion vector -> smaller filtering weight.
const MV mv = subblock_mvs[subblock_idx];
const double distance = sqrt(pow(mv.row, 2) + pow(mv.col, 2));
double distance_threshold = min_frame_size * TF_SEARCH_DISTANCE_THRESHOLD;
distance_threshold = AOMMAX(distance_threshold, 1);
d_factor[subblock_idx] = distance / distance_threshold;
d_factor[subblock_idx] = AOMMAX(d_factor[subblock_idx], 1);
}
// Handle planes in sequence.
int plane_offset = 0;
for (int plane = 0; plane < num_planes; ++plane) {
const uint32_t plane_h = mb_height >> mbd->plane[plane].subsampling_y;
const uint32_t plane_w = mb_width >> mbd->plane[plane].subsampling_x;
const uint32_t frame_stride =
frame_to_filter->strides[plane == AOM_PLANE_Y ? 0 : 1];
const uint32_t frame_sse_stride = plane_w;
const int frame_offset = mb_row * plane_h * frame_stride + mb_col * plane_w;
const uint16_t *ref =
CONVERT_TO_SHORTPTR(frame_to_filter->buffers[plane]) + frame_offset;
const int ss_x_shift =
mbd->plane[plane].subsampling_x - mbd->plane[AOM_PLANE_Y].subsampling_x;
const int ss_y_shift =
mbd->plane[plane].subsampling_y - mbd->plane[AOM_PLANE_Y].subsampling_y;
const int num_ref_pixels = TF_WINDOW_LENGTH * TF_WINDOW_LENGTH +
((plane) ? (1 << (ss_x_shift + ss_y_shift)) : 0);
const double inv_num_ref_pixels = 1.0 / num_ref_pixels;
// Larger noise -> larger filtering weight.
const double n_decay = 0.5 + log(2 * noise_levels[plane] + 5.0);
// Decay factors for non-local mean approach.
const double decay_factor = 1 / (n_decay * q_decay * s_decay);
// Filter U-plane and V-plane using Y-plane. This is because motion
// search is only done on Y-plane, so the information from Y-plane
// will be more accurate. The luma sse sum is reused in both chroma
// planes.
if (plane == AOM_PLANE_U) {
for (unsigned int i = 0; i < plane_h; i++) {
for (unsigned int j = 0; j < plane_w; j++) {
for (int ii = 0; ii < (1 << ss_y_shift); ++ii) {
for (int jj = 0; jj < (1 << ss_x_shift); ++jj) {
const int yy = (i << ss_y_shift) + ii; // Y-coord on Y-plane.
const int xx = (j << ss_x_shift) + jj; // X-coord on Y-plane.
const int ww = frame_sse_stride
<< ss_x_shift; // Width of Y-plane.
luma_sse_sum[i * BW + j] += frame_sse[yy * ww + xx];
}
}
}
}
}
get_squared_error(ref, frame_stride, pred + plane_offset, plane_w, plane_w,
plane_h, frame_sse, frame_sse_stride);
highbd_apply_temporal_filter(
pred + plane_offset, plane_w, plane_w, plane_h, subblock_mses,
accum + plane_offset, count + plane_offset, frame_sse, frame_sse_stride,
luma_sse_sum, inv_num_ref_pixels, decay_factor, inv_factor,
weight_factor, d_factor, tf_wgt_calc_lvl, mbd->bd);
plane_offset += plane_h * plane_w;
}
}
double av1_highbd_estimate_noise_from_single_plane_neon(const uint16_t *src,
int height, int width,
int stride,
int bitdepth,
int edge_thresh) {
uint16x8_t thresh = vdupq_n_u16(edge_thresh);
uint64x2_t acc = vdupq_n_u64(0);
// Count is in theory positive as it counts the number of times we're under
// the threshold, but it will be counted negatively in order to make best use
// of the vclt instruction, which sets every bit of a lane to 1 when the
// condition is true.
int32x4_t count = vdupq_n_s32(0);
int final_count = 0;
uint64_t final_acc = 0;
const uint16_t *src_start = src + stride + 1;
int h = 1;
do {
int w = 1;
const uint16_t *src_ptr = src_start;
while (w <= (width - 1) - 8) {
uint16x8_t mat[3][3];
mat[0][0] = vld1q_u16(src_ptr - stride - 1);
mat[0][1] = vld1q_u16(src_ptr - stride);
mat[0][2] = vld1q_u16(src_ptr - stride + 1);
mat[1][0] = vld1q_u16(src_ptr - 1);
mat[1][1] = vld1q_u16(src_ptr);
mat[1][2] = vld1q_u16(src_ptr + 1);
mat[2][0] = vld1q_u16(src_ptr + stride - 1);
mat[2][1] = vld1q_u16(src_ptr + stride);
mat[2][2] = vld1q_u16(src_ptr + stride + 1);
// Compute Sobel gradients.
uint16x8_t gxa = vaddq_u16(mat[0][0], mat[2][0]);
uint16x8_t gxb = vaddq_u16(mat[0][2], mat[2][2]);
gxa = vaddq_u16(gxa, vaddq_u16(mat[1][0], mat[1][0]));
gxb = vaddq_u16(gxb, vaddq_u16(mat[1][2], mat[1][2]));
uint16x8_t gya = vaddq_u16(mat[0][0], mat[0][2]);
uint16x8_t gyb = vaddq_u16(mat[2][0], mat[2][2]);
gya = vaddq_u16(gya, vaddq_u16(mat[0][1], mat[0][1]));
gyb = vaddq_u16(gyb, vaddq_u16(mat[2][1], mat[2][1]));
uint16x8_t ga = vabaq_u16(vabdq_u16(gxa, gxb), gya, gyb);
ga = vrshlq_u16(ga, vdupq_n_s16(8 - bitdepth));
// Check which vector elements are under the threshold. The Laplacian is
// then unconditionnally computed and we accumulate zeros if we're not
// under the threshold. This is much faster than using an if statement.
uint16x8_t thresh_u16 = vcltq_u16(ga, thresh);
uint16x8_t center = vshlq_n_u16(mat[1][1], 2);
uint16x8_t adj0 = vaddq_u16(mat[0][1], mat[2][1]);
uint16x8_t adj1 = vaddq_u16(mat[1][0], mat[1][2]);
uint16x8_t adj = vaddq_u16(adj0, adj1);
adj = vaddq_u16(adj, adj);
uint16x8_t diag0 = vaddq_u16(mat[0][0], mat[0][2]);
uint16x8_t diag1 = vaddq_u16(mat[2][0], mat[2][2]);
uint16x8_t diag = vaddq_u16(diag0, diag1);
uint16x8_t v = vabdq_u16(vaddq_u16(center, diag), adj);
v = vandq_u16(vrshlq_u16(v, vdupq_n_s16(8 - bitdepth)), thresh_u16);
uint32x4_t v_u32 = vpaddlq_u16(v);
acc = vpadalq_u32(acc, v_u32);
// Add -1 for each lane where the gradient is under the threshold.
count = vpadalq_s16(count, vreinterpretq_s16_u16(thresh_u16));
w += 8;
src_ptr += 8;
}
if (w <= (width - 1) - 4) {
uint16x4_t mat[3][3];
mat[0][0] = vld1_u16(src_ptr - stride - 1);
mat[0][1] = vld1_u16(src_ptr - stride);
mat[0][2] = vld1_u16(src_ptr - stride + 1);
mat[1][0] = vld1_u16(src_ptr - 1);
mat[1][1] = vld1_u16(src_ptr);
mat[1][2] = vld1_u16(src_ptr + 1);
mat[2][0] = vld1_u16(src_ptr + stride - 1);
mat[2][1] = vld1_u16(src_ptr + stride);
mat[2][2] = vld1_u16(src_ptr + stride + 1);
// Compute Sobel gradients.
uint16x4_t gxa = vadd_u16(mat[0][0], mat[2][0]);
uint16x4_t gxb = vadd_u16(mat[0][2], mat[2][2]);
gxa = vadd_u16(gxa, vadd_u16(mat[1][0], mat[1][0]));
gxb = vadd_u16(gxb, vadd_u16(mat[1][2], mat[1][2]));
uint16x4_t gya = vadd_u16(mat[0][0], mat[0][2]);
uint16x4_t gyb = vadd_u16(mat[2][0], mat[2][2]);
gya = vadd_u16(gya, vadd_u16(mat[0][1], mat[0][1]));
gyb = vadd_u16(gyb, vadd_u16(mat[2][1], mat[2][1]));
uint16x4_t ga = vaba_u16(vabd_u16(gxa, gxb), gya, gyb);
ga = vrshl_u16(ga, vdup_n_s16(8 - bitdepth));
// Check which vector elements are under the threshold. The Laplacian is
// then unconditionnally computed and we accumulate zeros if we're not
// under the threshold. This is much faster than using an if statement.
uint16x4_t thresh_u16 = vclt_u16(ga, vget_low_u16(thresh));
uint16x4_t center = vshl_n_u16(mat[1][1], 2);
uint16x4_t adj0 = vadd_u16(mat[0][1], mat[2][1]);
uint16x4_t adj1 = vadd_u16(mat[1][0], mat[1][2]);
uint16x4_t adj = vadd_u16(adj0, adj1);
adj = vadd_u16(adj, adj);
uint16x4_t diag0 = vadd_u16(mat[0][0], mat[0][2]);
uint16x4_t diag1 = vadd_u16(mat[2][0], mat[2][2]);
uint16x4_t diag = vadd_u16(diag0, diag1);
uint16x4_t v = vabd_u16(vadd_u16(center, diag), adj);
v = vand_u16(v, thresh_u16);
uint32x4_t v_u32 = vmovl_u16(vrshl_u16(v, vdup_n_s16(8 - bitdepth)));
acc = vpadalq_u32(acc, v_u32);
// Add -1 for each lane where the gradient is under the threshold.
count = vaddw_s16(count, vreinterpret_s16_u16(thresh_u16));
w += 4;
src_ptr += 4;
}
while (w < width - 1) {
int mat[3][3];
mat[0][0] = *(src_ptr - stride - 1);
mat[0][1] = *(src_ptr - stride);
mat[0][2] = *(src_ptr - stride + 1);
mat[1][0] = *(src_ptr - 1);
mat[1][1] = *(src_ptr);
mat[1][2] = *(src_ptr + 1);
mat[2][0] = *(src_ptr + stride - 1);
mat[2][1] = *(src_ptr + stride);
mat[2][2] = *(src_ptr + stride + 1);
// Compute Sobel gradients.
const int gx = (mat[0][0] - mat[0][2]) + (mat[2][0] - mat[2][2]) +
2 * (mat[1][0] - mat[1][2]);
const int gy = (mat[0][0] - mat[2][0]) + (mat[0][2] - mat[2][2]) +
2 * (mat[0][1] - mat[2][1]);
const int ga = ROUND_POWER_OF_TWO(abs(gx) + abs(gy), bitdepth - 8);
// Accumulate Laplacian.
const int is_under = ga < edge_thresh;
const int v = 4 * mat[1][1] -
2 * (mat[0][1] + mat[2][1] + mat[1][0] + mat[1][2]) +
(mat[0][0] + mat[0][2] + mat[2][0] + mat[2][2]);
final_acc += ROUND_POWER_OF_TWO(abs(v), bitdepth - 8) * is_under;
final_count += is_under;
src_ptr++;
w++;
}
src_start += stride;
} while (++h < height - 1);
// We counted negatively, so subtract to get the final value.
final_count -= horizontal_add_s32x4(count);
final_acc += horizontal_add_u64x2(acc);
return (final_count < 16)
? -1.0
: (double)final_acc / (6 * final_count) * SQRT_PI_BY_2;
}