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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "lib/jpegli/downsample.h"
#undef HWY_TARGET_INCLUDE
#define HWY_TARGET_INCLUDE "lib/jpegli/downsample.cc"
#include <hwy/foreach_target.h>
#include <hwy/highway.h>
#include "lib/jpegli/encode_internal.h"
#include "lib/jpegli/error.h"
HWY_BEFORE_NAMESPACE();
namespace jpegli {
namespace HWY_NAMESPACE {
// These templates are not found via ADL.
using hwy::HWY_NAMESPACE::Add;
using hwy::HWY_NAMESPACE::Mul;
using hwy::HWY_NAMESPACE::Vec;
using D = HWY_CAPPED(float, 8);
constexpr D d;
void DownsampleRow2x1(const float* row_in, size_t len, float* row_out) {
const size_t N = Lanes(d);
const size_t len_out = len / 2;
const auto mul = Set(d, 0.5f);
Vec<D> v0, v1; // NOLINT
for (size_t x = 0; x < len_out; x += N) {
LoadInterleaved2(d, row_in + 2 * x, v0, v1);
Store(Mul(mul, Add(v0, v1)), d, row_out + x);
}
}
void DownsampleRow3x1(const float* row_in, size_t len, float* row_out) {
const size_t N = Lanes(d);
const size_t len_out = len / 3;
const auto mul = Set(d, 1.0f / 3);
Vec<D> v0, v1, v2; // NOLINT
for (size_t x = 0; x < len_out; x += N) {
LoadInterleaved3(d, row_in + 3 * x, v0, v1, v2);
Store(Mul(mul, Add(Add(v0, v1), v2)), d, row_out + x);
}
}
void DownsampleRow4x1(const float* row_in, size_t len, float* row_out) {
const size_t N = Lanes(d);
const size_t len_out = len / 4;
const auto mul = Set(d, 0.25f);
Vec<D> v0, v1, v2, v3; // NOLINT
for (size_t x = 0; x < len_out; x += N) {
LoadInterleaved4(d, row_in + 4 * x, v0, v1, v2, v3);
Store(Mul(mul, Add(Add(v0, v1), Add(v2, v3))), d, row_out + x);
}
}
void Downsample2x1(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
DownsampleRow2x1(rows_in[0], len, row_out);
}
void Downsample3x1(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
DownsampleRow3x1(rows_in[0], len, row_out);
}
void Downsample4x1(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
DownsampleRow4x1(rows_in[0], len, row_out);
}
void Downsample1x2(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
const size_t N = Lanes(d);
const auto mul = Set(d, 0.5f);
float* row0 = rows_in[0];
float* row1 = rows_in[1];
for (size_t x = 0; x < len; x += N) {
Store(Mul(mul, Add(Load(d, row0 + x), Load(d, row1 + x))), d, row_out + x);
}
}
void Downsample2x2(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
const size_t N = Lanes(d);
const size_t len_out = len / 2;
const auto mul = Set(d, 0.25f);
float* row0 = rows_in[0];
float* row1 = rows_in[1];
Vec<D> v0, v1, v2, v3; // NOLINT
for (size_t x = 0; x < len_out; x += N) {
LoadInterleaved2(d, row0 + 2 * x, v0, v1);
LoadInterleaved2(d, row1 + 2 * x, v2, v3);
Store(Mul(mul, Add(Add(v0, v1), Add(v2, v3))), d, row_out + x);
}
}
void Downsample3x2(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
DownsampleRow3x1(rows_in[0], len, rows_in[0]);
DownsampleRow3x1(rows_in[1], len, rows_in[1]);
Downsample1x2(rows_in, len / 3, row_out);
}
void Downsample4x2(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
DownsampleRow4x1(rows_in[0], len, rows_in[0]);
DownsampleRow4x1(rows_in[1], len, rows_in[1]);
Downsample1x2(rows_in, len / 4, row_out);
}
void Downsample1x3(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
const size_t N = Lanes(d);
const auto mul = Set(d, 1.0f / 3);
float* row0 = rows_in[0];
float* row1 = rows_in[1];
float* row2 = rows_in[2];
for (size_t x = 0; x < len; x += N) {
const auto in0 = Load(d, row0 + x);
const auto in1 = Load(d, row1 + x);
const auto in2 = Load(d, row2 + x);
Store(Mul(mul, Add(Add(in0, in1), in2)), d, row_out + x);
}
}
void Downsample2x3(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
DownsampleRow2x1(rows_in[0], len, rows_in[0]);
DownsampleRow2x1(rows_in[1], len, rows_in[1]);
DownsampleRow2x1(rows_in[2], len, rows_in[2]);
Downsample1x3(rows_in, len / 2, row_out);
}
void Downsample3x3(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
DownsampleRow3x1(rows_in[0], len, rows_in[0]);
DownsampleRow3x1(rows_in[1], len, rows_in[1]);
DownsampleRow3x1(rows_in[2], len, rows_in[2]);
Downsample1x3(rows_in, len / 3, row_out);
}
void Downsample4x3(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
DownsampleRow4x1(rows_in[0], len, rows_in[0]);
DownsampleRow4x1(rows_in[1], len, rows_in[1]);
DownsampleRow4x1(rows_in[2], len, rows_in[2]);
Downsample1x3(rows_in, len / 4, row_out);
}
void Downsample1x4(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
const size_t N = Lanes(d);
const auto mul = Set(d, 0.25f);
float* row0 = rows_in[0];
float* row1 = rows_in[1];
float* row2 = rows_in[2];
float* row3 = rows_in[3];
for (size_t x = 0; x < len; x += N) {
const auto in0 = Load(d, row0 + x);
const auto in1 = Load(d, row1 + x);
const auto in2 = Load(d, row2 + x);
const auto in3 = Load(d, row3 + x);
Store(Mul(mul, Add(Add(in0, in1), Add(in2, in3))), d, row_out + x);
}
}
void Downsample2x4(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
DownsampleRow2x1(rows_in[0], len, rows_in[0]);
DownsampleRow2x1(rows_in[1], len, rows_in[1]);
DownsampleRow2x1(rows_in[2], len, rows_in[2]);
DownsampleRow2x1(rows_in[3], len, rows_in[3]);
Downsample1x4(rows_in, len / 2, row_out);
}
void Downsample3x4(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
DownsampleRow3x1(rows_in[0], len, rows_in[0]);
DownsampleRow3x1(rows_in[1], len, rows_in[1]);
DownsampleRow3x1(rows_in[2], len, rows_in[2]);
DownsampleRow3x1(rows_in[3], len, rows_in[3]);
Downsample1x4(rows_in, len / 3, row_out);
}
void Downsample4x4(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {
DownsampleRow4x1(rows_in[0], len, rows_in[0]);
DownsampleRow4x1(rows_in[1], len, rows_in[1]);
DownsampleRow4x1(rows_in[2], len, rows_in[2]);
DownsampleRow4x1(rows_in[3], len, rows_in[3]);
Downsample1x4(rows_in, len / 4, row_out);
}
// NOLINTNEXTLINE(google-readability-namespace-comments)
} // namespace HWY_NAMESPACE
} // namespace jpegli
HWY_AFTER_NAMESPACE();
#if HWY_ONCE
namespace jpegli {
HWY_EXPORT(Downsample1x2);
HWY_EXPORT(Downsample1x3);
HWY_EXPORT(Downsample1x4);
HWY_EXPORT(Downsample2x1);
HWY_EXPORT(Downsample2x2);
HWY_EXPORT(Downsample2x3);
HWY_EXPORT(Downsample2x4);
HWY_EXPORT(Downsample3x1);
HWY_EXPORT(Downsample3x2);
HWY_EXPORT(Downsample3x3);
HWY_EXPORT(Downsample3x4);
HWY_EXPORT(Downsample4x1);
HWY_EXPORT(Downsample4x2);
HWY_EXPORT(Downsample4x3);
HWY_EXPORT(Downsample4x4);
void NullDownsample(float* rows_in[MAX_SAMP_FACTOR], size_t len,
float* row_out) {}
void ChooseDownsampleMethods(j_compress_ptr cinfo) {
jpeg_comp_master* m = cinfo->master;
for (int c = 0; c < cinfo->num_components; c++) {
m->downsample_method[c] = nullptr;
jpeg_component_info* comp = &cinfo->comp_info[c];
const int h_factor = cinfo->max_h_samp_factor / comp->h_samp_factor;
const int v_factor = cinfo->max_v_samp_factor / comp->v_samp_factor;
if (v_factor == 1) {
if (h_factor == 1) {
m->downsample_method[c] = NullDownsample;
} else if (h_factor == 2) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample2x1);
} else if (h_factor == 3) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample3x1);
} else if (h_factor == 4) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample4x1);
}
} else if (v_factor == 2) {
if (h_factor == 1) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample1x2);
} else if (h_factor == 2) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample2x2);
} else if (h_factor == 3) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample3x2);
} else if (h_factor == 4) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample4x2);
}
} else if (v_factor == 3) {
if (h_factor == 1) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample1x2);
} else if (h_factor == 2) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample2x2);
} else if (h_factor == 3) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample3x2);
} else if (h_factor == 4) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample4x2);
}
} else if (v_factor == 4) {
if (h_factor == 1) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample1x4);
} else if (h_factor == 2) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample2x4);
} else if (h_factor == 3) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample3x4);
} else if (h_factor == 4) {
m->downsample_method[c] = HWY_DYNAMIC_DISPATCH(Downsample4x4);
}
}
if (m->downsample_method[c] == nullptr) {
JPEGLI_ERROR("Unsupported downsampling ratio %dx%d", h_factor, v_factor);
}
}
}
void DownsampleInputBuffer(j_compress_ptr cinfo) {
if (cinfo->max_h_samp_factor == 1 && cinfo->max_v_samp_factor == 1) {
return;
}
jpeg_comp_master* m = cinfo->master;
const size_t iMCU_height = DCTSIZE * cinfo->max_v_samp_factor;
const size_t y0 = m->next_iMCU_row * iMCU_height;
const size_t y1 = y0 + iMCU_height;
const size_t xsize_padded = m->xsize_blocks * DCTSIZE;
for (int c = 0; c < cinfo->num_components; c++) {
jpeg_component_info* comp = &cinfo->comp_info[c];
const int h_factor = cinfo->max_h_samp_factor / comp->h_samp_factor;
const int v_factor = cinfo->max_v_samp_factor / comp->v_samp_factor;
if (h_factor == 1 && v_factor == 1) {
continue;
}
auto& input = *m->smooth_input[c];
auto& output = *m->raw_data[c];
const size_t y_out0 = y0 / v_factor;
float* rows_in[MAX_SAMP_FACTOR];
for (size_t y_in = y0, y_out = y_out0; y_in < y1;
y_in += v_factor, ++y_out) {
for (int iy = 0; iy < v_factor; ++iy) {
rows_in[iy] = input.Row(y_in + iy);
}
float* row_out = output.Row(y_out);
(*m->downsample_method[c])(rows_in, xsize_padded, row_out);
}
}
}
void ApplyInputSmoothing(j_compress_ptr cinfo) {
if (!cinfo->smoothing_factor) {
return;
}
jpeg_comp_master* m = cinfo->master;
const float kW1 = cinfo->smoothing_factor / 1024.0;
const float kW0 = 1.0f - 8.0f * kW1;
const size_t iMCU_height = DCTSIZE * cinfo->max_v_samp_factor;
const ssize_t y0 = m->next_iMCU_row * iMCU_height;
const ssize_t y1 = y0 + iMCU_height;
const ssize_t xsize_padded = m->xsize_blocks * DCTSIZE;
for (int c = 0; c < cinfo->num_components; c++) {
auto& input = m->input_buffer[c];
auto& output = *m->smooth_input[c];
if (m->next_iMCU_row == 0) {
input.CopyRow(-1, 0, 1);
}
if (m->next_iMCU_row + 1 == cinfo->total_iMCU_rows) {
size_t last_row = m->ysize_blocks * DCTSIZE - 1;
input.CopyRow(last_row + 1, last_row, 1);
}
// TODO(szabadka) SIMDify this.
for (ssize_t y = y0; y < y1; ++y) {
const float* row_t = input.Row(y - 1);
const float* row_m = input.Row(y);
const float* row_b = input.Row(y + 1);
float* row_out = output.Row(y);
for (ssize_t x = 0; x < xsize_padded; ++x) {
float val_tl = row_t[x - 1];
float val_tm = row_t[x];
float val_tr = row_t[x + 1];
float val_ml = row_m[x - 1];
float val_mm = row_m[x];
float val_mr = row_m[x + 1];
float val_bl = row_b[x - 1];
float val_bm = row_b[x];
float val_br = row_b[x + 1];
float val1 = (val_tl + val_tm + val_tr + val_ml + val_mr + val_bl +
val_bm + val_br);
row_out[x] = val_mm * kW0 + val1 * kW1;
}
}
}
}
} // namespace jpegli
#endif // HWY_ONCE