1 /*
2 * vivid-color.c - A table that converts colors to various colorspaces
3 *
4 * The test pattern generator uses the tpg_colors for its test patterns.
5 * For testing colorspaces the first 8 colors of that table need to be
6 * converted to their equivalent in the target colorspace.
7 *
8 * The tpg_csc_colors[] table is the result of that conversion and since
9 * it is precalculated the colorspace conversion is just a simple table
10 * lookup.
11 *
12 * This source also contains the code used to generate the tpg_csc_colors
13 * table. Run the following command to compile it:
14 *
15 * gcc vivid-colors.c -DCOMPILE_APP -o gen-colors -lm
16 *
17 * and run the utility.
18 *
19 * Note that the converted colors are in the range 0x000-0xff0 (so times 16)
20 * in order to preserve precision.
21 *
22 * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
23 *
24 * This program is free software; you may redistribute it and/or modify
25 * it under the terms of the GNU General Public License as published by
26 * the Free Software Foundation; version 2 of the License.
27 *
28 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
29 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
30 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
31 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
32 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
33 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
34 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
35 * SOFTWARE.
36 */
37
38 #include <linux/videodev2.h>
39
40 #include "vivid-tpg-colors.h"
41
42 /* sRGB colors with range [0-255] */
43 const struct color tpg_colors[TPG_COLOR_MAX] = {
44 /*
45 * Colors to test colorspace conversion: converting these colors
46 * to other colorspaces will never lead to out-of-gamut colors.
47 */
48 { 191, 191, 191 }, /* TPG_COLOR_CSC_WHITE */
49 { 191, 191, 50 }, /* TPG_COLOR_CSC_YELLOW */
50 { 50, 191, 191 }, /* TPG_COLOR_CSC_CYAN */
51 { 50, 191, 50 }, /* TPG_COLOR_CSC_GREEN */
52 { 191, 50, 191 }, /* TPG_COLOR_CSC_MAGENTA */
53 { 191, 50, 50 }, /* TPG_COLOR_CSC_RED */
54 { 50, 50, 191 }, /* TPG_COLOR_CSC_BLUE */
55 { 50, 50, 50 }, /* TPG_COLOR_CSC_BLACK */
56
57 /* 75% colors */
58 { 191, 191, 0 }, /* TPG_COLOR_75_YELLOW */
59 { 0, 191, 191 }, /* TPG_COLOR_75_CYAN */
60 { 0, 191, 0 }, /* TPG_COLOR_75_GREEN */
61 { 191, 0, 191 }, /* TPG_COLOR_75_MAGENTA */
62 { 191, 0, 0 }, /* TPG_COLOR_75_RED */
63 { 0, 0, 191 }, /* TPG_COLOR_75_BLUE */
64
65 /* 100% colors */
66 { 255, 255, 255 }, /* TPG_COLOR_100_WHITE */
67 { 255, 255, 0 }, /* TPG_COLOR_100_YELLOW */
68 { 0, 255, 255 }, /* TPG_COLOR_100_CYAN */
69 { 0, 255, 0 }, /* TPG_COLOR_100_GREEN */
70 { 255, 0, 255 }, /* TPG_COLOR_100_MAGENTA */
71 { 255, 0, 0 }, /* TPG_COLOR_100_RED */
72 { 0, 0, 255 }, /* TPG_COLOR_100_BLUE */
73 { 0, 0, 0 }, /* TPG_COLOR_100_BLACK */
74
75 { 0, 0, 0 }, /* TPG_COLOR_RANDOM placeholder */
76 };
77
78 #ifndef COMPILE_APP
79
80 /* Generated table */
81 const struct color16 tpg_csc_colors[V4L2_COLORSPACE_SRGB + 1][TPG_COLOR_CSC_BLACK + 1] = {
82 [V4L2_COLORSPACE_SMPTE170M][0] = { 2953, 2939, 2939 },
83 [V4L2_COLORSPACE_SMPTE170M][1] = { 2954, 2963, 585 },
84 [V4L2_COLORSPACE_SMPTE170M][2] = { 84, 2967, 2937 },
85 [V4L2_COLORSPACE_SMPTE170M][3] = { 93, 2990, 575 },
86 [V4L2_COLORSPACE_SMPTE170M][4] = { 3030, 259, 2933 },
87 [V4L2_COLORSPACE_SMPTE170M][5] = { 3031, 406, 557 },
88 [V4L2_COLORSPACE_SMPTE170M][6] = { 544, 428, 2931 },
89 [V4L2_COLORSPACE_SMPTE170M][7] = { 551, 547, 547 },
90 [V4L2_COLORSPACE_SMPTE240M][0] = { 2926, 2926, 2926 },
91 [V4L2_COLORSPACE_SMPTE240M][1] = { 2926, 2926, 857 },
92 [V4L2_COLORSPACE_SMPTE240M][2] = { 1594, 2901, 2901 },
93 [V4L2_COLORSPACE_SMPTE240M][3] = { 1594, 2901, 774 },
94 [V4L2_COLORSPACE_SMPTE240M][4] = { 2484, 618, 2858 },
95 [V4L2_COLORSPACE_SMPTE240M][5] = { 2484, 618, 617 },
96 [V4L2_COLORSPACE_SMPTE240M][6] = { 507, 507, 2832 },
97 [V4L2_COLORSPACE_SMPTE240M][7] = { 507, 507, 507 },
98 [V4L2_COLORSPACE_REC709][0] = { 2939, 2939, 2939 },
99 [V4L2_COLORSPACE_REC709][1] = { 2939, 2939, 547 },
100 [V4L2_COLORSPACE_REC709][2] = { 547, 2939, 2939 },
101 [V4L2_COLORSPACE_REC709][3] = { 547, 2939, 547 },
102 [V4L2_COLORSPACE_REC709][4] = { 2939, 547, 2939 },
103 [V4L2_COLORSPACE_REC709][5] = { 2939, 547, 547 },
104 [V4L2_COLORSPACE_REC709][6] = { 547, 547, 2939 },
105 [V4L2_COLORSPACE_REC709][7] = { 547, 547, 547 },
106 [V4L2_COLORSPACE_470_SYSTEM_M][0] = { 2894, 2988, 2808 },
107 [V4L2_COLORSPACE_470_SYSTEM_M][1] = { 2847, 3070, 843 },
108 [V4L2_COLORSPACE_470_SYSTEM_M][2] = { 1656, 2962, 2783 },
109 [V4L2_COLORSPACE_470_SYSTEM_M][3] = { 1572, 3045, 763 },
110 [V4L2_COLORSPACE_470_SYSTEM_M][4] = { 2477, 229, 2743 },
111 [V4L2_COLORSPACE_470_SYSTEM_M][5] = { 2422, 672, 614 },
112 [V4L2_COLORSPACE_470_SYSTEM_M][6] = { 725, 63, 2718 },
113 [V4L2_COLORSPACE_470_SYSTEM_M][7] = { 534, 561, 509 },
114 [V4L2_COLORSPACE_470_SYSTEM_BG][0] = { 2939, 2939, 2939 },
115 [V4L2_COLORSPACE_470_SYSTEM_BG][1] = { 2939, 2939, 621 },
116 [V4L2_COLORSPACE_470_SYSTEM_BG][2] = { 786, 2939, 2939 },
117 [V4L2_COLORSPACE_470_SYSTEM_BG][3] = { 786, 2939, 621 },
118 [V4L2_COLORSPACE_470_SYSTEM_BG][4] = { 2879, 547, 2923 },
119 [V4L2_COLORSPACE_470_SYSTEM_BG][5] = { 2879, 547, 547 },
120 [V4L2_COLORSPACE_470_SYSTEM_BG][6] = { 547, 547, 2923 },
121 [V4L2_COLORSPACE_470_SYSTEM_BG][7] = { 547, 547, 547 },
122 [V4L2_COLORSPACE_SRGB][0] = { 3056, 3056, 3056 },
123 [V4L2_COLORSPACE_SRGB][1] = { 3056, 3056, 800 },
124 [V4L2_COLORSPACE_SRGB][2] = { 800, 3056, 3056 },
125 [V4L2_COLORSPACE_SRGB][3] = { 800, 3056, 800 },
126 [V4L2_COLORSPACE_SRGB][4] = { 3056, 800, 3056 },
127 [V4L2_COLORSPACE_SRGB][5] = { 3056, 800, 800 },
128 [V4L2_COLORSPACE_SRGB][6] = { 800, 800, 3056 },
129 [V4L2_COLORSPACE_SRGB][7] = { 800, 800, 800 },
130 };
131
132 #else
133
134 /* This code generates the table above */
135
136 #include <math.h>
137 #include <stdio.h>
138 #include <stdlib.h>
139
140 static const double rec709_to_ntsc1953[3][3] = {
141 { 0.6698, 0.2678, 0.0323 },
142 { 0.0185, 1.0742, -0.0603 },
143 { 0.0162, 0.0432, 0.8551 }
144 };
145
146 static const double rec709_to_ebu[3][3] = {
147 { 0.9578, 0.0422, 0 },
148 { 0 , 1 , 0 },
149 { 0 , 0.0118, 0.9882 }
150 };
151
152 static const double rec709_to_170m[3][3] = {
153 { 1.0654, -0.0554, -0.0010 },
154 { -0.0196, 1.0364, -0.0167 },
155 { 0.0016, 0.0044, 0.9940 }
156 };
157
158 static const double rec709_to_240m[3][3] = {
159 { 0.7151, 0.2849, 0 },
160 { 0.0179, 0.9821, 0 },
161 { 0.0177, 0.0472, 0.9350 }
162 };
163
164
mult_matrix(double * r,double * g,double * b,const double m[3][3])165 static void mult_matrix(double *r, double *g, double *b, const double m[3][3])
166 {
167 double ir, ig, ib;
168
169 ir = m[0][0] * (*r) + m[0][1] * (*g) + m[0][2] * (*b);
170 ig = m[1][0] * (*r) + m[1][1] * (*g) + m[1][2] * (*b);
171 ib = m[2][0] * (*r) + m[2][1] * (*g) + m[2][2] * (*b);
172 *r = ir;
173 *g = ig;
174 *b = ib;
175 }
176
transfer_srgb_to_rgb(double v)177 static double transfer_srgb_to_rgb(double v)
178 {
179 return (v <= 0.03928) ? v / 12.92 : pow((v + 0.055) / 1.055, 2.4);
180 }
181
transfer_rgb_to_smpte240m(double v)182 static double transfer_rgb_to_smpte240m(double v)
183 {
184 return (v <= 0.0228) ? v * 4.0 : 1.1115 * pow(v, 0.45) - 0.1115;
185 }
186
transfer_rgb_to_rec709(double v)187 static double transfer_rgb_to_rec709(double v)
188 {
189 return (v < 0.018) ? v * 4.5 : 1.099 * pow(v, 0.45) - 0.099;
190 }
191
transfer_srgb_to_rec709(double v)192 static double transfer_srgb_to_rec709(double v)
193 {
194 return transfer_rgb_to_rec709(transfer_srgb_to_rgb(v));
195 }
196
csc(enum v4l2_colorspace colorspace,double * r,double * g,double * b)197 static void csc(enum v4l2_colorspace colorspace, double *r, double *g, double *b)
198 {
199 /* Convert the primaries of Rec. 709 Linear RGB */
200 switch (colorspace) {
201 case V4L2_COLORSPACE_SMPTE240M:
202 *r = transfer_srgb_to_rgb(*r);
203 *g = transfer_srgb_to_rgb(*g);
204 *b = transfer_srgb_to_rgb(*b);
205 mult_matrix(r, g, b, rec709_to_240m);
206 break;
207 case V4L2_COLORSPACE_SMPTE170M:
208 *r = transfer_srgb_to_rgb(*r);
209 *g = transfer_srgb_to_rgb(*g);
210 *b = transfer_srgb_to_rgb(*b);
211 mult_matrix(r, g, b, rec709_to_170m);
212 break;
213 case V4L2_COLORSPACE_470_SYSTEM_BG:
214 *r = transfer_srgb_to_rgb(*r);
215 *g = transfer_srgb_to_rgb(*g);
216 *b = transfer_srgb_to_rgb(*b);
217 mult_matrix(r, g, b, rec709_to_ebu);
218 break;
219 case V4L2_COLORSPACE_470_SYSTEM_M:
220 *r = transfer_srgb_to_rgb(*r);
221 *g = transfer_srgb_to_rgb(*g);
222 *b = transfer_srgb_to_rgb(*b);
223 mult_matrix(r, g, b, rec709_to_ntsc1953);
224 break;
225 case V4L2_COLORSPACE_SRGB:
226 case V4L2_COLORSPACE_REC709:
227 default:
228 break;
229 }
230
231 *r = ((*r) < 0) ? 0 : (((*r) > 1) ? 1 : (*r));
232 *g = ((*g) < 0) ? 0 : (((*g) > 1) ? 1 : (*g));
233 *b = ((*b) < 0) ? 0 : (((*b) > 1) ? 1 : (*b));
234
235 /* Encode to gamma corrected colorspace */
236 switch (colorspace) {
237 case V4L2_COLORSPACE_SMPTE240M:
238 *r = transfer_rgb_to_smpte240m(*r);
239 *g = transfer_rgb_to_smpte240m(*g);
240 *b = transfer_rgb_to_smpte240m(*b);
241 break;
242 case V4L2_COLORSPACE_SMPTE170M:
243 case V4L2_COLORSPACE_470_SYSTEM_M:
244 case V4L2_COLORSPACE_470_SYSTEM_BG:
245 *r = transfer_rgb_to_rec709(*r);
246 *g = transfer_rgb_to_rec709(*g);
247 *b = transfer_rgb_to_rec709(*b);
248 break;
249 case V4L2_COLORSPACE_SRGB:
250 break;
251 case V4L2_COLORSPACE_REC709:
252 default:
253 *r = transfer_srgb_to_rec709(*r);
254 *g = transfer_srgb_to_rec709(*g);
255 *b = transfer_srgb_to_rec709(*b);
256 break;
257 }
258 }
259
main(int argc,char ** argv)260 int main(int argc, char **argv)
261 {
262 static const unsigned colorspaces[] = {
263 0,
264 V4L2_COLORSPACE_SMPTE170M,
265 V4L2_COLORSPACE_SMPTE240M,
266 V4L2_COLORSPACE_REC709,
267 0,
268 V4L2_COLORSPACE_470_SYSTEM_M,
269 V4L2_COLORSPACE_470_SYSTEM_BG,
270 0,
271 V4L2_COLORSPACE_SRGB,
272 };
273 static const char * const colorspace_names[] = {
274 "",
275 "V4L2_COLORSPACE_SMPTE170M",
276 "V4L2_COLORSPACE_SMPTE240M",
277 "V4L2_COLORSPACE_REC709",
278 "",
279 "V4L2_COLORSPACE_470_SYSTEM_M",
280 "V4L2_COLORSPACE_470_SYSTEM_BG",
281 "",
282 "V4L2_COLORSPACE_SRGB",
283 };
284 int i;
285 int c;
286
287 printf("/* Generated table */\n");
288 printf("const struct color16 tpg_csc_colors[V4L2_COLORSPACE_SRGB + 1][TPG_COLOR_CSC_BLACK + 1] = {\n");
289 for (c = 0; c <= V4L2_COLORSPACE_SRGB; c++) {
290 for (i = 0; i <= TPG_COLOR_CSC_BLACK; i++) {
291 double r, g, b;
292
293 if (colorspaces[c] == 0)
294 continue;
295
296 r = tpg_colors[i].r / 255.0;
297 g = tpg_colors[i].g / 255.0;
298 b = tpg_colors[i].b / 255.0;
299
300 csc(c, &r, &g, &b);
301
302 printf("\t[%s][%d] = { %d, %d, %d },\n", colorspace_names[c], i,
303 (int)(r * 4080), (int)(g * 4080), (int)(b * 4080));
304 }
305 }
306 printf("};\n\n");
307 return 0;
308 }
309
310 #endif
311