1 /*
2 * Copyright (c) 2020 Björn Ottosson
3 * Copyright (c) 2022 Clément Bœsch <u pkh me>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
24
25 #define K ((1 << 16) - 1)
26 #define K2 ((int64_t)K*K)
27 #define P ((1 << 9) - 1)
28
29 /**
30 * Table mapping formula:
31 * f(x) = x < 0.04045 ? x/12.92 : ((x+0.055)/1.055)^2.4 (sRGB EOTF)
32 * Where x is the normalized index in the table and f(x) the value in the table.
33 * f(x) is remapped to [0;K] and rounded.
34 */
36 0x0000, 0x0014, 0x0028, 0x003c, 0x0050, 0x0063, 0x0077, 0x008b,
37 0x009f, 0x00b3, 0x00c7, 0x00db, 0x00f1, 0x0108, 0x0120, 0x0139,
38 0x0154, 0x016f, 0x018c, 0x01ab, 0x01ca, 0x01eb, 0x020e, 0x0232,
39 0x0257, 0x027d, 0x02a5, 0x02ce, 0x02f9, 0x0325, 0x0353, 0x0382,
40 0x03b3, 0x03e5, 0x0418, 0x044d, 0x0484, 0x04bc, 0x04f6, 0x0532,
41 0x056f, 0x05ad, 0x05ed, 0x062f, 0x0673, 0x06b8, 0x06fe, 0x0747,
42 0x0791, 0x07dd, 0x082a, 0x087a, 0x08ca, 0x091d, 0x0972, 0x09c8,
43 0x0a20, 0x0a79, 0x0ad5, 0x0b32, 0x0b91, 0x0bf2, 0x0c55, 0x0cba,
44 0x0d20, 0x0d88, 0x0df2, 0x0e5e, 0x0ecc, 0x0f3c, 0x0fae, 0x1021,
45 0x1097, 0x110e, 0x1188, 0x1203, 0x1280, 0x1300, 0x1381, 0x1404,
46 0x1489, 0x1510, 0x159a, 0x1625, 0x16b2, 0x1741, 0x17d3, 0x1866,
47 0x18fb, 0x1993, 0x1a2c, 0x1ac8, 0x1b66, 0x1c06, 0x1ca7, 0x1d4c,
48 0x1df2, 0x1e9a, 0x1f44, 0x1ff1, 0x20a0, 0x2150, 0x2204, 0x22b9,
49 0x2370, 0x242a, 0x24e5, 0x25a3, 0x2664, 0x2726, 0x27eb, 0x28b1,
50 0x297b, 0x2a46, 0x2b14, 0x2be3, 0x2cb6, 0x2d8a, 0x2e61, 0x2f3a,
51 0x3015, 0x30f2, 0x31d2, 0x32b4, 0x3399, 0x3480, 0x3569, 0x3655,
52 0x3742, 0x3833, 0x3925, 0x3a1a, 0x3b12, 0x3c0b, 0x3d07, 0x3e06,
53 0x3f07, 0x400a, 0x4110, 0x4218, 0x4323, 0x4430, 0x453f, 0x4651,
54 0x4765, 0x487c, 0x4995, 0x4ab1, 0x4bcf, 0x4cf0, 0x4e13, 0x4f39,
55 0x5061, 0x518c, 0x52b9, 0x53e9, 0x551b, 0x5650, 0x5787, 0x58c1,
56 0x59fe, 0x5b3d, 0x5c7e, 0x5dc2, 0x5f09, 0x6052, 0x619e, 0x62ed,
57 0x643e, 0x6591, 0x66e8, 0x6840, 0x699c, 0x6afa, 0x6c5b, 0x6dbe,
58 0x6f24, 0x708d, 0x71f8, 0x7366, 0x74d7, 0x764a, 0x77c0, 0x7939,
59 0x7ab4, 0x7c32, 0x7db3, 0x7f37, 0x80bd, 0x8246, 0x83d1, 0x855f,
60 0x86f0, 0x8884, 0x8a1b, 0x8bb4, 0x8d50, 0x8eef, 0x9090, 0x9235,
61 0x93dc, 0x9586, 0x9732, 0x98e2, 0x9a94, 0x9c49, 0x9e01, 0x9fbb,
62 0xa179, 0xa339, 0xa4fc, 0xa6c2, 0xa88b, 0xaa56, 0xac25, 0xadf6,
63 0xafca, 0xb1a1, 0xb37b, 0xb557, 0xb737, 0xb919, 0xbaff, 0xbce7,
64 0xbed2, 0xc0c0, 0xc2b1, 0xc4a5, 0xc69c, 0xc895, 0xca92, 0xcc91,
65 0xce94, 0xd099, 0xd2a1, 0xd4ad, 0xd6bb, 0xd8cc, 0xdae0, 0xdcf7,
66 0xdf11, 0xe12e, 0xe34e, 0xe571, 0xe797, 0xe9c0, 0xebec, 0xee1b,
67 0xf04d, 0xf282, 0xf4ba, 0xf6f5, 0xf933, 0xfb74, 0xfdb8, 0xffff,
68 };
69
70 /**
71 * Table mapping formula:
72 * f(x) = x < 0.0031308 ? x*12.92 : 1.055*x^(1/2.4)-0.055 (sRGB OETF)
73 * Where x is the normalized index in the table and f(x) the value in the table.
74 * f(x) is remapped to [0;0xff] and rounded.
75 *
76 * Since a 16-bit table is too large, we reduce its precision to 9-bit.
77 */
79 0x00, 0x06, 0x0d, 0x12, 0x16, 0x19, 0x1c, 0x1f, 0x22, 0x24, 0x26, 0x28, 0x2a, 0x2c, 0x2e, 0x30,
80 0x32, 0x33, 0x35, 0x36, 0x38, 0x39, 0x3b, 0x3c, 0x3d, 0x3e, 0x40, 0x41, 0x42, 0x43, 0x45, 0x46,
81 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56,
82 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5b, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 0x5f, 0x60, 0x61, 0x62, 0x62,
83 0x63, 0x64, 0x65, 0x65, 0x66, 0x67, 0x67, 0x68, 0x69, 0x6a, 0x6a, 0x6b, 0x6c, 0x6c, 0x6d, 0x6e,
84 0x6e, 0x6f, 0x6f, 0x70, 0x71, 0x71, 0x72, 0x73, 0x73, 0x74, 0x74, 0x75, 0x76, 0x76, 0x77, 0x77,
85 0x78, 0x79, 0x79, 0x7a, 0x7a, 0x7b, 0x7b, 0x7c, 0x7d, 0x7d, 0x7e, 0x7e, 0x7f, 0x7f, 0x80, 0x80,
86 0x81, 0x81, 0x82, 0x82, 0x83, 0x84, 0x84, 0x85, 0x85, 0x86, 0x86, 0x87, 0x87, 0x88, 0x88, 0x89,
87 0x89, 0x8a, 0x8a, 0x8b, 0x8b, 0x8c, 0x8c, 0x8c, 0x8d, 0x8d, 0x8e, 0x8e, 0x8f, 0x8f, 0x90, 0x90,
88 0x91, 0x91, 0x92, 0x92, 0x93, 0x93, 0x93, 0x94, 0x94, 0x95, 0x95, 0x96, 0x96, 0x97, 0x97, 0x97,
89 0x98, 0x98, 0x99, 0x99, 0x9a, 0x9a, 0x9a, 0x9b, 0x9b, 0x9c, 0x9c, 0x9c, 0x9d, 0x9d, 0x9e, 0x9e,
90 0x9f, 0x9f, 0x9f, 0xa0, 0xa0, 0xa1, 0xa1, 0xa1, 0xa2, 0xa2, 0xa3, 0xa3, 0xa3, 0xa4, 0xa4, 0xa5,
91 0xa5, 0xa5, 0xa6, 0xa6, 0xa6, 0xa7, 0xa7, 0xa8, 0xa8, 0xa8, 0xa9, 0xa9, 0xa9, 0xaa, 0xaa, 0xab,
92 0xab, 0xab, 0xac, 0xac, 0xac, 0xad, 0xad, 0xae, 0xae, 0xae, 0xaf, 0xaf, 0xaf, 0xb0, 0xb0, 0xb0,
93 0xb1, 0xb1, 0xb1, 0xb2, 0xb2, 0xb3, 0xb3, 0xb3, 0xb4, 0xb4, 0xb4, 0xb5, 0xb5, 0xb5, 0xb6, 0xb6,
94 0xb6, 0xb7, 0xb7, 0xb7, 0xb8, 0xb8, 0xb8, 0xb9, 0xb9, 0xb9, 0xba, 0xba, 0xba, 0xbb, 0xbb, 0xbb,
95 0xbc, 0xbc, 0xbc, 0xbd, 0xbd, 0xbd, 0xbe, 0xbe, 0xbe, 0xbf, 0xbf, 0xbf, 0xc0, 0xc0, 0xc0, 0xc1,
96 0xc1, 0xc1, 0xc1, 0xc2, 0xc2, 0xc2, 0xc3, 0xc3, 0xc3, 0xc4, 0xc4, 0xc4, 0xc5, 0xc5, 0xc5, 0xc6,
97 0xc6, 0xc6, 0xc6, 0xc7, 0xc7, 0xc7, 0xc8, 0xc8, 0xc8, 0xc9, 0xc9, 0xc9, 0xc9, 0xca, 0xca, 0xca,
98 0xcb, 0xcb, 0xcb, 0xcc, 0xcc, 0xcc, 0xcc, 0xcd, 0xcd, 0xcd, 0xce, 0xce, 0xce, 0xce, 0xcf, 0xcf,
99 0xcf, 0xd0, 0xd0, 0xd0, 0xd0, 0xd1, 0xd1, 0xd1, 0xd2, 0xd2, 0xd2, 0xd2, 0xd3, 0xd3, 0xd3, 0xd4,
100 0xd4, 0xd4, 0xd4, 0xd5, 0xd5, 0xd5, 0xd6, 0xd6, 0xd6, 0xd6, 0xd7, 0xd7, 0xd7, 0xd7, 0xd8, 0xd8,
101 0xd8, 0xd9, 0xd9, 0xd9, 0xd9, 0xda, 0xda, 0xda, 0xda, 0xdb, 0xdb, 0xdb, 0xdc, 0xdc, 0xdc, 0xdc,
102 0xdd, 0xdd, 0xdd, 0xdd, 0xde, 0xde, 0xde, 0xde, 0xdf, 0xdf, 0xdf, 0xe0, 0xe0, 0xe0, 0xe0, 0xe1,
103 0xe1, 0xe1, 0xe1, 0xe2, 0xe2, 0xe2, 0xe2, 0xe3, 0xe3, 0xe3, 0xe3, 0xe4, 0xe4, 0xe4, 0xe4, 0xe5,
104 0xe5, 0xe5, 0xe5, 0xe6, 0xe6, 0xe6, 0xe6, 0xe7, 0xe7, 0xe7, 0xe7, 0xe8, 0xe8, 0xe8, 0xe8, 0xe9,
105 0xe9, 0xe9, 0xe9, 0xea, 0xea, 0xea, 0xea, 0xeb, 0xeb, 0xeb, 0xeb, 0xec, 0xec, 0xec, 0xec, 0xed,
106 0xed, 0xed, 0xed, 0xee, 0xee, 0xee, 0xee, 0xef, 0xef, 0xef, 0xef, 0xef, 0xf0, 0xf0, 0xf0, 0xf0,
107 0xf1, 0xf1, 0xf1, 0xf1, 0xf2, 0xf2, 0xf2, 0xf2, 0xf3, 0xf3, 0xf3, 0xf3, 0xf3, 0xf4, 0xf4, 0xf4,
108 0xf4, 0xf5, 0xf5, 0xf5, 0xf5, 0xf6, 0xf6, 0xf6, 0xf6, 0xf6, 0xf7, 0xf7, 0xf7, 0xf7, 0xf8, 0xf8,
109 0xf8, 0xf8, 0xf9, 0xf9, 0xf9, 0xf9, 0xf9, 0xfa, 0xfa, 0xfa, 0xfa, 0xfb, 0xfb, 0xfb, 0xfb, 0xfb,
110 0xfc, 0xfc, 0xfc, 0xfc, 0xfd, 0xfd, 0xfd, 0xfd, 0xfd, 0xfe, 0xfe, 0xfe, 0xfe, 0xff, 0xff, 0xff,
111 };
112
114 {
115 if (x <= 0) {
116 return 0;
118 return 0xff;
119 } else {
125 return (m * (y1 - y0) +
K/2) /
K + y0;
126 }
127 }
128
129 /* Integer cube root, working only within [0;1] */
131 {
133
134 /* Approximation curve is for the [0;1] range */
135 if (x <= 0) return 0;
136 if (x >=
K)
return K;
137
138 /*
139 * Initial approximation: x3 - 2.19893x2 + 2.01593x + 0.219407
140 *
141 * We are not using any rounding here since the precision is not important
142 * at this stage and it would require the more expensive rounding function
143 * that deals with negative numbers.
144 */
145 u = x*(x*(x + -144107LL) /
K + 132114LL) /
K + 14379LL;
146
147 /*
148 * Refine with 2 Halley iterations:
149 * un+1 = un-2f(un)f'(un)/(2f'(un)2-f(un)f"(un))
150 * = un(2x+un3)/(x+2un3)
151 *
152 * Note: u is not expected to be < 0, so we can use the (a+b/2)/b rounding.
153 */
154 for (
int i = 0;
i < 2;
i++) {
157 u = (
u * (2*x + (u3 +
K2/2) /
K2) + den/2) / den;
158 }
159
161 }
162
164
166 {
170
171 // Note: lms can actually be slightly over K due to rounded coefficients
172 const int32_t l = (27015LL*
r + 35149LL*
g + 3372LL*
b +
K/2) /
K;
173 const int32_t m = (13887LL*
r + 44610LL*
g + 7038LL*
b +
K/2) /
K;
174 const int32_t s = ( 5787LL*
r + 18462LL*
g + 41286LL*
b +
K/2) /
K;
175
179
181 .L =
div_round64( 13792LL*l_ + 52010LL*m_ - 267LL*s_,
K),
182 .a =
div_round64(129628LL*l_ - 159158LL*m_ + 29530LL*s_,
K),
183 .b =
div_round64( 1698LL*l_ + 51299LL*m_ - 52997LL*s_,
K),
184 };
185
187 }
188
190 {
194
198
202
203 return r<<16 |
g<<8 |
b;
204 }
205
207 {
208 x ^= x >> 16;
209 x *= 0x7feb352d;
210 x ^= x >> 15;
211 x *= 0x846ca68b;
212 x ^= x >> 16;
213 return x;
214 }