1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
// 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.
#if defined(LIB_JXL_CMS_TONE_MAPPING_INL_H_) == defined(HWY_TARGET_TOGGLE)
#ifdef LIB_JXL_CMS_TONE_MAPPING_INL_H_
#undef LIB_JXL_CMS_TONE_MAPPING_INL_H_
#else
#define LIB_JXL_CMS_TONE_MAPPING_INL_H_
#endif
#include <hwy/highway.h>
#include "lib/jxl/cms/tone_mapping.h"
#include "lib/jxl/cms/transfer_functions-inl.h"
HWY_BEFORE_NAMESPACE();
namespace jxl {
namespace HWY_NAMESPACE {
namespace {
// These templates are not found via ADL.
using hwy::HWY_NAMESPACE::Clamp;
using hwy::HWY_NAMESPACE::Max;
using hwy::HWY_NAMESPACE::ZeroIfNegative;
template <typename D>
class Rec2408ToneMapper : Rec2408ToneMapperBase {
private:
using V = hwy::HWY_NAMESPACE::Vec<D>;
public:
using Rec2408ToneMapperBase::Rec2408ToneMapperBase;
void ToneMap(V* red, V* green, V* blue) const {
const V luminance = Mul(Set(df_, source_range_.second),
(MulAdd(Set(df_, red_Y_), *red,
MulAdd(Set(df_, green_Y_), *green,
Mul(Set(df_, blue_Y_), *blue)))));
const V pq_mastering_min = Set(df_, pq_mastering_min_);
const V inv_pq_mastering_range = Set(df_, inv_pq_mastering_range_);
const V normalized_pq = Min(
Set(df_, 1.f),
Mul(Sub(InvEOTF(luminance), pq_mastering_min), inv_pq_mastering_range));
const V ks = Set(df_, ks_);
const V e2 =
IfThenElse(Lt(normalized_pq, ks), normalized_pq, P(normalized_pq));
const V one_minus_e2 = Sub(Set(df_, 1), e2);
const V one_minus_e2_2 = Mul(one_minus_e2, one_minus_e2);
const V one_minus_e2_4 = Mul(one_minus_e2_2, one_minus_e2_2);
const V b = Set(df_, min_lum_);
const V e3 = MulAdd(b, one_minus_e2_4, e2);
const V pq_mastering_range = Set(df_, pq_mastering_range_);
const V e4 = MulAdd(e3, pq_mastering_range, pq_mastering_min);
const V new_luminance =
Min(Set(df_, target_range_.second),
ZeroIfNegative(tf_pq_.DisplayFromEncoded(df_, e4)));
const V min_luminance = Set(df_, 1e-6f);
const auto use_cap = Le(luminance, min_luminance);
const V ratio = Div(new_luminance, Max(luminance, min_luminance));
const V cap = Mul(new_luminance, Set(df_, inv_target_peak_));
const V normalizer = Set(df_, normalizer_);
const V multiplier = Mul(ratio, normalizer);
for (V* const val : {red, green, blue}) {
*val = IfThenElse(use_cap, cap, Mul(*val, multiplier));
}
}
private:
V InvEOTF(const V luminance) const {
return tf_pq_.EncodedFromDisplay(df_, luminance);
}
V T(const V a) const {
const V ks = Set(df_, ks_);
const V inv_one_minus_ks = Set(df_, inv_one_minus_ks_);
return Mul(Sub(a, ks), inv_one_minus_ks);
}
V P(const V b) const {
const V t_b = T(b);
const V t_b_2 = Mul(t_b, t_b);
const V t_b_3 = Mul(t_b_2, t_b);
const V ks = Set(df_, ks_);
const V max_lum = Set(df_, max_lum_);
return MulAdd(
MulAdd(Set(df_, 2), t_b_3, MulAdd(Set(df_, -3), t_b_2, Set(df_, 1))),
ks,
MulAdd(Add(t_b_3, MulAdd(Set(df_, -2), t_b_2, t_b)),
Sub(Set(df_, 1), ks),
Mul(MulAdd(Set(df_, -2), t_b_3, Mul(Set(df_, 3), t_b_2)),
max_lum)));
}
D df_;
const TF_PQ tf_pq_ = TF_PQ(/*display_intensity_target=*/1.0);
};
class HlgOOTF : HlgOOTF_Base {
public:
using HlgOOTF_Base::HlgOOTF_Base;
static HlgOOTF FromSceneLight(float display_luminance,
const Vector3& primaries_luminances) {
return HlgOOTF(/*gamma=*/1.2f *
std::pow(1.111f, std::log2(display_luminance / 1000.f)),
primaries_luminances);
}
static HlgOOTF ToSceneLight(float display_luminance,
const Vector3& primaries_luminances) {
return HlgOOTF(
/*gamma=*/(1 / 1.2f) *
std::pow(1.111f, -std::log2(display_luminance / 1000.f)),
primaries_luminances);
}
template <typename V>
void Apply(V* red, V* green, V* blue) const {
hwy::HWY_NAMESPACE::DFromV<V> df;
if (!apply_ootf_) return;
const V luminance =
MulAdd(Set(df, red_Y_), *red,
MulAdd(Set(df, green_Y_), *green, Mul(Set(df, blue_Y_), *blue)));
const V ratio =
Min(FastPowf(df, luminance, Set(df, exponent_)), Set(df, 1e9));
*red = Mul(*red, ratio);
*green = Mul(*green, ratio);
*blue = Mul(*blue, ratio);
}
bool WarrantsGamutMapping() const { return apply_ootf_ && exponent_ < 0; }
};
template <typename V>
void GamutMap(V* red, V* green, V* blue, const Vector3& primaries_luminances,
float preserve_saturation = 0.1f) {
hwy::HWY_NAMESPACE::DFromV<V> df;
const V luminance =
MulAdd(Set(df, primaries_luminances[0]), *red,
MulAdd(Set(df, primaries_luminances[1]), *green,
Mul(Set(df, primaries_luminances[2]), *blue)));
// Desaturate out-of-gamut pixels. This is done by mixing each pixel
// with just enough gray of the target luminance to make all
// components non-negative.
// - For saturation preservation, if a component is still larger than
// 1 then the pixel is normalized to have a maximum component of 1.
// That will reduce its luminance.
// - For luminance preservation, getting all components below 1 is
// done by mixing in yet more gray. That will desaturate it further.
const V zero = Zero(df);
const V one = Set(df, 1);
V gray_mix_saturation = zero;
V gray_mix_luminance = zero;
for (const V* ch : {red, green, blue}) {
const V& val = *ch;
const V val_minus_gray = Sub(val, luminance);
const V inv_val_minus_gray =
Div(one, IfThenElse(Eq(val_minus_gray, zero), one, val_minus_gray));
const V val_over_val_minus_gray = Mul(val, inv_val_minus_gray);
gray_mix_saturation =
IfThenElse(Ge(val_minus_gray, zero), gray_mix_saturation,
Max(gray_mix_saturation, val_over_val_minus_gray));
gray_mix_luminance =
Max(gray_mix_luminance,
IfThenElse(Le(val_minus_gray, zero), gray_mix_saturation,
Sub(val_over_val_minus_gray, inv_val_minus_gray)));
}
const V gray_mix = Clamp(
MulAdd(Set(df, preserve_saturation),
Sub(gray_mix_saturation, gray_mix_luminance), gray_mix_luminance),
zero, one);
for (V* const ch : {red, green, blue}) {
V& val = *ch;
val = MulAdd(gray_mix, Sub(luminance, val), val);
}
const V max_clr = Max(Max(one, *red), Max(*green, *blue));
const V normalizer = Div(one, max_clr);
for (V* const ch : {red, green, blue}) {
V& val = *ch;
val = Mul(val, normalizer);
}
}
} // namespace
// NOLINTNEXTLINE(google-readability-namespace-comments)
} // namespace HWY_NAMESPACE
} // namespace jxl
HWY_AFTER_NAMESPACE();
#endif // LIB_JXL_CMS_TONE_MAPPING_INL_H_
|
