FFmpeg: libavutil/csp.c Source File

FFmpeg

libavutil

csp.c

Go to the documentation of this file.

1 /*

2 * Copyright (c) 2015 Kevin Wheatley <kevin.j.wheatley@gmail.com>

3 * Copyright (c) 2016 Ronald S. Bultje <rsbultje@gmail.com>

4 * Copyright (c) 2023 Leo Izen <leo.izen@gmail.com>

5 *

6 * This file is part of FFmpeg.

7 *

8 * FFmpeg is free software; you can redistribute it and/or

9 * modify it under the terms of the GNU Lesser General Public

10 * License as published by the Free Software Foundation; either

11 * version 2.1 of the License, or (at your option) any later version.

12 *

13 * FFmpeg is distributed in the hope that it will be useful,

14 * but WITHOUT ANY WARRANTY; without even the implied warranty of

15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

16 * Lesser General Public License for more details.

17 *

18 * You should have received a copy of the GNU Lesser General Public

19 * License along with FFmpeg; if not, write to the Free Software

20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

21 */

22

23 /**

24 * @file Colorspace functions for libavutil

25 * @author Ronald S. Bultje <rsbultje@gmail.com>

26 * @author Leo Izen <leo.izen@gmail.com>

27 * @author Kevin Wheatley <kevin.j.wheatley@gmail.com>

28 */

29

30 #include <stdlib.h>

31 #include <math.h>

32

33 #include "attributes.h"

34 #include "csp.h"

35 #include "pixfmt.h"

36 #include "rational.h"

37

38 #define AVR(d) { (int)(d * 100000 + 0.5), 100000 }

39

40 /*

41 * All constants explained in e.g. https://linuxtv.org/downloads/v4l-dvb-apis/ch02s06.html

42 * The older ones (bt470bg/m) are also explained in their respective ITU docs

43 * (e.g. https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.470-5-199802-S!!PDF-E.pdf)

44 * whereas the newer ones can typically be copied directly from wikipedia :)

45 */

46 static const struct AVLumaCoefficients luma_coefficients[AVCOL_SPC_NB] = {

47 [AVCOL_SPC_FCC] = { AVR(0.30), AVR(0.59), AVR(0.11) },

48 [AVCOL_SPC_BT470BG] = { AVR(0.299), AVR(0.587), AVR(0.114) },

49 [AVCOL_SPC_SMPTE170M] = { AVR(0.299), AVR(0.587), AVR(0.114) },

50 [AVCOL_SPC_BT709] = { AVR(0.2126), AVR(0.7152), AVR(0.0722) },

51 [AVCOL_SPC_SMPTE240M] = { AVR(0.212), AVR(0.701), AVR(0.087) },

52 [AVCOL_SPC_YCOCG] = { AVR(0.25), AVR(0.5), AVR(0.25) },

53 [AVCOL_SPC_RGB] = { AVR(1), AVR(1), AVR(1) },

54 [AVCOL_SPC_BT2020_NCL] = { AVR(0.2627), AVR(0.6780), AVR(0.0593) },

55 [AVCOL_SPC_BT2020_CL] = { AVR(0.2627), AVR(0.6780), AVR(0.0593) },

56 };

57

58 const struct AVLumaCoefficients *av_csp_luma_coeffs_from_avcsp(enum AVColorSpace csp)

59 {

60 const AVLumaCoefficients *coeffs;

61

62 if (csp >= AVCOL_SPC_NB)

63 return NULL;

64 coeffs = &luma_coefficients[csp];

65 if (!coeffs->cr.num)

66 return NULL;

67

68 return coeffs;

69 }

70

71 #define WP_D65 { AVR(0.3127), AVR(0.3290) }

72 #define WP_C { AVR(0.3100), AVR(0.3160) }

73 #define WP_DCI { AVR(0.3140), AVR(0.3510) }

74 #define WP_E { {1, 3}, {1, 3} }

75

76 static const AVColorPrimariesDesc color_primaries[AVCOL_PRI_NB] = {

77 [AVCOL_PRI_BT709] = { WP_D65, { { AVR(0.640), AVR(0.330) }, { AVR(0.300), AVR(0.600) }, { AVR(0.150), AVR(0.060) } } },

78 [AVCOL_PRI_BT470M] = { WP_C, { { AVR(0.670), AVR(0.330) }, { AVR(0.210), AVR(0.710) }, { AVR(0.140), AVR(0.080) } } },

79 [AVCOL_PRI_BT470BG] = { WP_D65, { { AVR(0.640), AVR(0.330) }, { AVR(0.290), AVR(0.600) }, { AVR(0.150), AVR(0.060) } } },

80 [AVCOL_PRI_SMPTE170M] = { WP_D65, { { AVR(0.630), AVR(0.340) }, { AVR(0.310), AVR(0.595) }, { AVR(0.155), AVR(0.070) } } },

81 [AVCOL_PRI_SMPTE240M] = { WP_D65, { { AVR(0.630), AVR(0.340) }, { AVR(0.310), AVR(0.595) }, { AVR(0.155), AVR(0.070) } } },

82 [AVCOL_PRI_SMPTE428] = { WP_E, { { AVR(0.735), AVR(0.265) }, { AVR(0.274), AVR(0.718) }, { AVR(0.167), AVR(0.009) } } },

83 [AVCOL_PRI_SMPTE431] = { WP_DCI, { { AVR(0.680), AVR(0.320) }, { AVR(0.265), AVR(0.690) }, { AVR(0.150), AVR(0.060) } } },

84 [AVCOL_PRI_SMPTE432] = { WP_D65, { { AVR(0.680), AVR(0.320) }, { AVR(0.265), AVR(0.690) }, { AVR(0.150), AVR(0.060) } } },

85 [AVCOL_PRI_FILM] = { WP_C, { { AVR(0.681), AVR(0.319) }, { AVR(0.243), AVR(0.692) }, { AVR(0.145), AVR(0.049) } } },

86 [AVCOL_PRI_BT2020] = { WP_D65, { { AVR(0.708), AVR(0.292) }, { AVR(0.170), AVR(0.797) }, { AVR(0.131), AVR(0.046) } } },

87 [AVCOL_PRI_JEDEC_P22] = { WP_D65, { { AVR(0.630), AVR(0.340) }, { AVR(0.295), AVR(0.605) }, { AVR(0.155), AVR(0.077) } } },

88 };

89

90 const AVColorPrimariesDesc *av_csp_primaries_desc_from_id(enum AVColorPrimaries prm)

91 {

92 const AVColorPrimariesDesc *p;

93

94 if (prm >= AVCOL_PRI_NB)

95 return NULL;

96 p = &color_primaries[prm];

97 if (!p->prim.r.x.num)

98 return NULL;

99

100 return p;

101 }

102

103 static av_always_inline AVRational abs_sub_q(AVRational r1, AVRational r2)

104 {

105 AVRational diff = av_sub_q(r1, r2);

106 /* denominator assumed to be positive */

107 return av_make_q(abs(diff.num), diff.den);

108 }

109

110 enum AVColorPrimaries av_csp_primaries_id_from_desc(const AVColorPrimariesDesc *prm)

111 {

112 AVRational delta;

113

114 for (enum AVColorPrimaries p = 0; p < AVCOL_PRI_NB; p++) {

115 const AVColorPrimariesDesc *ref = &color_primaries[p];

116 if (!ref->prim.r.x.num)

117 continue;

118

119 delta = abs_sub_q(prm->prim.r.x, ref->prim.r.x);

120 delta = av_add_q(delta, abs_sub_q(prm->prim.r.y, ref->prim.r.y));

121 delta = av_add_q(delta, abs_sub_q(prm->prim.g.x, ref->prim.g.x));

122 delta = av_add_q(delta, abs_sub_q(prm->prim.g.y, ref->prim.g.y));

123 delta = av_add_q(delta, abs_sub_q(prm->prim.b.x, ref->prim.b.x));

124 delta = av_add_q(delta, abs_sub_q(prm->prim.b.y, ref->prim.b.y));

125 delta = av_add_q(delta, abs_sub_q(prm->wp.x, ref->wp.x));

126 delta = av_add_q(delta, abs_sub_q(prm->wp.y, ref->wp.y));

127

128 if (av_cmp_q(delta, av_make_q(1, 1000)) < 0)

129 return p;

130 }

131

132 return AVCOL_PRI_UNSPECIFIED;

133 }

134

135 static const double approximate_gamma[AVCOL_TRC_NB] = {

136 [AVCOL_TRC_BT709] = 1.961,

137 [AVCOL_TRC_SMPTE170M] = 1.961,

138 [AVCOL_TRC_SMPTE240M] = 1.961,

139 [AVCOL_TRC_BT1361_ECG] = 1.961,

140 [AVCOL_TRC_BT2020_10] = 1.961,

141 [AVCOL_TRC_BT2020_12] = 1.961,

142 [AVCOL_TRC_GAMMA22] = 2.2,

143 [AVCOL_TRC_IEC61966_2_1] = 2.2,

144 [AVCOL_TRC_GAMMA28] = 2.8,

145 [AVCOL_TRC_LINEAR] = 1.0,

146 [AVCOL_TRC_SMPTE428] = 2.6,

147 };

148

149 double av_csp_approximate_trc_gamma(enum AVColorTransferCharacteristic trc)

150 {

151 double gamma;

152 if (trc >= AVCOL_TRC_NB)

153 return 0.0;

154 gamma = approximate_gamma[trc];

155 if (gamma > 0)

156 return gamma;

157 return 0.0;

158 }

159

160 #define BT709_alpha 1.099296826809442

161 #define BT709_beta 0.018053968510807

162

163 static double trc_bt709(double Lc)

164 {

165 const double a = BT709_alpha;

166 const double b = BT709_beta;

167

168 return (0.0 > Lc) ? 0.0

169 : ( b > Lc) ? 4.500 * Lc

170 : a * pow(Lc, 0.45) - (a - 1.0);

171 }

172

173 static double trc_gamma22(double Lc)

174 {

175 return (0.0 > Lc) ? 0.0 : pow(Lc, 1.0/ 2.2);

176 }

177

178 static double trc_gamma28(double Lc)

179 {

180 return (0.0 > Lc) ? 0.0 : pow(Lc, 1.0/ 2.8);

181 }

182

183 static double trc_smpte240M(double Lc)

184 {

185 const double a = 1.1115;

186 const double b = 0.0228;

187

188 return (0.0 > Lc) ? 0.0

189 : ( b > Lc) ? 4.000 * Lc

190 : a * pow(Lc, 0.45) - (a - 1.0);

191 }

192

193 static double trc_linear(double Lc)

194 {

195 return Lc;

196 }

197

198 static double trc_log(double Lc)

199 {

200 return (0.01 > Lc) ? 0.0 : 1.0 + log10(Lc) / 2.0;

201 }

202

203 static double trc_log_sqrt(double Lc)

204 {

205 // sqrt(10) / 1000

206 return (0.00316227766 > Lc) ? 0.0 : 1.0 + log10(Lc) / 2.5;

207 }

208

209 static double trc_iec61966_2_4(double Lc)

210 {

211 const double a = BT709_alpha;

212 const double b = BT709_beta;

213

214 return (-b >= Lc) ? -a * pow(-Lc, 0.45) + (a - 1.0)

215 : ( b > Lc) ? 4.500 * Lc

216 : a * pow( Lc, 0.45) - (a - 1.0);

217 }

218

219 static double trc_bt1361(double Lc)

220 {

221 const double a = BT709_alpha;

222 const double b = BT709_beta;

223

224 return (-0.0045 >= Lc) ? -(a * pow(-4.0 * Lc, 0.45) + (a - 1.0)) / 4.0

225 : ( b > Lc) ? 4.500 * Lc

226 : a * pow( Lc, 0.45) - (a - 1.0);

227 }

228

229 static double trc_iec61966_2_1(double Lc)

230 {

231 const double a = 1.055;

232 const double b = 0.0031308;

233

234 return (0.0 > Lc) ? 0.0

235 : ( b > Lc) ? 12.92 * Lc

236 : a * pow(Lc, 1.0 / 2.4) - (a - 1.0);

237 }

238

239 static double trc_smpte_st2084(double Lc)

240 {

241 const double c1 = 3424.0 / 4096.0; // c3-c2 + 1

242 const double c2 = 32.0 * 2413.0 / 4096.0;

243 const double c3 = 32.0 * 2392.0 / 4096.0;

244 const double m = 128.0 * 2523.0 / 4096.0;

245 const double n = 0.25 * 2610.0 / 4096.0;

246 const double L = Lc / 10000.0;

247 const double Ln = pow(L, n);

248

249 return (0.0 > Lc) ? 0.0

250 : pow((c1 + c2 * Ln) / (1.0 + c3 * Ln), m);

251

252 }

253

254 static double trc_smpte_st428_1(double Lc)

255 {

256 return (0.0 > Lc) ? 0.0

257 : pow(48.0 * Lc / 52.37, 1.0 / 2.6);

258 }

259

260

261 static double trc_arib_std_b67(double Lc) {

262 // The function uses the definition from HEVC, which assumes that the peak

263 // white is input level = 1. (this is equivalent to scaling E = Lc * 12 and

264 // using the definition from the ARIB STD-B67 spec)

265 const double a = 0.17883277;

266 const double b = 0.28466892;

267 const double c = 0.55991073;

268 return (0.0 > Lc) ? 0.0 :

269 (Lc <= 1.0 / 12.0 ? sqrt(3.0 * Lc) : a * log(12.0 * Lc - b) + c);

270 }

271

272 static const av_csp_trc_function trc_funcs[AVCOL_TRC_NB] = {

273 [AVCOL_TRC_BT709] = trc_bt709,

274 [AVCOL_TRC_GAMMA22] = trc_gamma22,

275 [AVCOL_TRC_GAMMA28] = trc_gamma28,

276 [AVCOL_TRC_SMPTE170M] = trc_bt709,

277 [AVCOL_TRC_SMPTE240M] = trc_smpte240M,

278 [AVCOL_TRC_LINEAR] = trc_linear,

279 [AVCOL_TRC_LOG] = trc_log,

280 [AVCOL_TRC_LOG_SQRT] = trc_log_sqrt,

281 [AVCOL_TRC_IEC61966_2_4] = trc_iec61966_2_4,

282 [AVCOL_TRC_BT1361_ECG] = trc_bt1361,

283 [AVCOL_TRC_IEC61966_2_1] = trc_iec61966_2_1,

284 [AVCOL_TRC_BT2020_10] = trc_bt709,

285 [AVCOL_TRC_BT2020_12] = trc_bt709,

286 [AVCOL_TRC_SMPTE2084] = trc_smpte_st2084,

287 [AVCOL_TRC_SMPTE428] = trc_smpte_st428_1,

288 [AVCOL_TRC_ARIB_STD_B67] = trc_arib_std_b67,

289 };

290

291 av_csp_trc_function av_csp_trc_func_from_id(enum AVColorTransferCharacteristic trc)

292 {

293 av_csp_trc_function func;

294 if (trc >= AVCOL_TRC_NB)

295 return NULL;

296 func = trc_funcs[trc];

297 if (!func)

298 return NULL;

299 return func;

300 }

AVLumaCoefficients::cr

AVRational cr

Definition: csp.h:49

int(* func)(AVBPrint *dst, const char *in, const char *arg)

Definition: jacosubdec.c:68

static av_always_inline AVRational abs_sub_q(AVRational r1, AVRational r2)

Definition: csp.c:103

AVColorTransferCharacteristic

AVColorTransferCharacteristic

Color Transfer Characteristic.

Definition: pixfmt.h:580

AVColorPrimariesDesc::wp

AVWhitepointCoefficients wp

Definition: csp.h:79

static double trc_smpte240M(double Lc)

Definition: csp.c:183

AVColorPrimariesDesc

Struct that contains both white point location and primaries location, providing the complete descrip...

Definition: csp.h:78

#define WP_D65

Definition: csp.c:71

AVCOL_TRC_LINEAR

@ AVCOL_TRC_LINEAR

"Linear transfer characteristics"

Definition: pixfmt.h:589

log

Definition: normalize.py:21

@ AVCOL_TRC_NB

Not part of ABI.

Definition: pixfmt.h:602

AVCOL_SPC_YCOCG

@ AVCOL_SPC_YCOCG

Definition: pixfmt.h:619

av_csp_luma_coeffs_from_avcsp

const struct AVLumaCoefficients * av_csp_luma_coeffs_from_avcsp(enum AVColorSpace csp)

Retrieves the Luma coefficients necessary to construct a conversion matrix from an enum constant desc...

Definition: csp.c:58

@ AVCOL_SPC_NB

Not part of ABI.

Definition: pixfmt.h:626

b

#define b

Definition: input.c:41

AVCOL_PRI_JEDEC_P22

@ AVCOL_PRI_JEDEC_P22

Definition: pixfmt.h:572

@ AVCOL_SPC_RGB

order of coefficients is actually GBR, also IEC 61966-2-1 (sRGB), YZX and ST 428-1

Definition: pixfmt.h:610

AVCOL_TRC_BT2020_12

@ AVCOL_TRC_BT2020_12

ITU-R BT2020 for 12-bit system.

Definition: pixfmt.h:596

AVLumaCoefficients

Struct containing luma coefficients to be used for RGB to YUV/YCoCg, or similar calculations.

Definition: csp.h:48

AVColorPrimaries

AVColorPrimaries

Chromaticity coordinates of the source primaries.

Definition: pixfmt.h:555

static const uint64_t c1

Definition: murmur3.c:52

AVRational av_sub_q(AVRational b, AVRational c)

Subtract one rational from another.

Definition: rational.c:101

AVCOL_SPC_BT2020_CL

@ AVCOL_SPC_BT2020_CL

ITU-R BT2020 constant luminance system.

Definition: pixfmt.h:621

av_csp_trc_func_from_id

av_csp_trc_function av_csp_trc_func_from_id(enum AVColorTransferCharacteristic trc)

Determine the function needed to apply the given AVColorTransferCharacteristic to linear input.

Definition: csp.c:291

AVCOL_SPC_BT470BG

@ AVCOL_SPC_BT470BG

also ITU-R BT601-6 625 / ITU-R BT1358 625 / ITU-R BT1700 625 PAL & SECAM / IEC 61966-2-4 xvYCC601

Definition: pixfmt.h:615

AVCOL_TRC_IEC61966_2_1

@ AVCOL_TRC_IEC61966_2_1

IEC 61966-2-1 (sRGB or sYCC)

Definition: pixfmt.h:594

#define WP_C

Definition: csp.c:72

#define BT709_alpha

Definition: csp.c:160

AVCOL_TRC_GAMMA28

@ AVCOL_TRC_GAMMA28

also ITU-R BT470BG

Definition: pixfmt.h:586

static double trc_gamma22(double Lc)

Definition: csp.c:173

AVCOL_TRC_LOG_SQRT

@ AVCOL_TRC_LOG_SQRT

"Logarithmic transfer characteristic (100 * Sqrt(10) : 1 range)"

Definition: pixfmt.h:591

AVRational::num

int num

Numerator.

Definition: rational.h:59

AVCOL_TRC_GAMMA22

@ AVCOL_TRC_GAMMA22

also ITU-R BT470M / ITU-R BT1700 625 PAL & SECAM

Definition: pixfmt.h:585

trc_iec61966_2_1

static double trc_iec61966_2_1(double Lc)

Definition: csp.c:229

@ AVCOL_PRI_NB

Not part of ABI.

Definition: pixfmt.h:573

av_csp_primaries_desc_from_id

const AVColorPrimariesDesc * av_csp_primaries_desc_from_id(enum AVColorPrimaries prm)

Retrieves a complete gamut description from an enum constant describing the color primaries.

Definition: csp.c:90

AVCOL_TRC_BT1361_ECG

@ AVCOL_TRC_BT1361_ECG

ITU-R BT1361 Extended Colour Gamut.

Definition: pixfmt.h:593

AVCOL_SPC_SMPTE170M

@ AVCOL_SPC_SMPTE170M

also ITU-R BT601-6 525 / ITU-R BT1358 525 / ITU-R BT1700 NTSC / functionally identical to above

Definition: pixfmt.h:616

approximate_gamma

static const double approximate_gamma[AVCOL_TRC_NB]

Definition: csp.c:135

AVCOL_PRI_SMPTE428

@ AVCOL_PRI_SMPTE428

SMPTE ST 428-1 (CIE 1931 XYZ)

Definition: pixfmt.h:567

av_csp_primaries_id_from_desc

enum AVColorPrimaries av_csp_primaries_id_from_desc(const AVColorPrimariesDesc *prm)

Detects which enum AVColorPrimaries constant corresponds to the given complete gamut description.

Definition: csp.c:110

AVCOL_PRI_SMPTE240M

@ AVCOL_PRI_SMPTE240M

identical to above, also called "SMPTE C" even though it uses D65

Definition: pixfmt.h:564

AVCOL_PRI_UNSPECIFIED

@ AVCOL_PRI_UNSPECIFIED

Definition: pixfmt.h:558

AVCOL_PRI_BT470BG

@ AVCOL_PRI_BT470BG

also ITU-R BT601-6 625 / ITU-R BT1358 625 / ITU-R BT1700 625 PAL & SECAM

Definition: pixfmt.h:562

AVCOL_PRI_SMPTE170M

@ AVCOL_PRI_SMPTE170M

also ITU-R BT601-6 525 / ITU-R BT1358 525 / ITU-R BT1700 NTSC

Definition: pixfmt.h:563

#define NULL

Definition: coverity.c:32

Rational number (pair of numerator and denominator).

Definition: rational.h:58

AVCOL_TRC_IEC61966_2_4

@ AVCOL_TRC_IEC61966_2_4

IEC 61966-2-4.

Definition: pixfmt.h:592

static const av_csp_trc_function trc_funcs[AVCOL_TRC_NB]

Definition: csp.c:272

AVCOL_PRI_BT709

@ AVCOL_PRI_BT709

also ITU-R BT1361 / IEC 61966-2-4 / SMPTE RP 177 Annex B

Definition: pixfmt.h:557

#define BT709_beta

Definition: csp.c:161

static double trc_bt1361(double Lc)

Definition: csp.c:219

AVCOL_TRC_BT2020_10

@ AVCOL_TRC_BT2020_10

ITU-R BT2020 for 10-bit system.

Definition: pixfmt.h:595

#define abs(x)

Definition: cuda_runtime.h:35

c

Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c

Definition: undefined.txt:32

AVCOL_PRI_BT2020

@ AVCOL_PRI_BT2020

ITU-R BT2020.

Definition: pixfmt.h:566

AVRational x

Definition: csp.h:57

color_primaries

static const AVColorPrimariesDesc color_primaries[AVCOL_PRI_NB]

Definition: csp.c:76

AVCOL_TRC_SMPTE2084

@ AVCOL_TRC_SMPTE2084

SMPTE ST 2084 for 10-, 12-, 14- and 16-bit systems.

Definition: pixfmt.h:597

AVPrimaryCoefficients::b

AVCIExy b

Definition: csp.h:65

AVCOL_PRI_SMPTE431

@ AVCOL_PRI_SMPTE431

SMPTE ST 431-2 (2011) / DCI P3.

Definition: pixfmt.h:569

AVPrimaryCoefficients::r

AVCIExy r

Definition: csp.h:65

AVCOL_TRC_SMPTE240M

@ AVCOL_TRC_SMPTE240M

Definition: pixfmt.h:588

@ AVCOL_PRI_FILM

colour filters using Illuminant C

Definition: pixfmt.h:565

static double trc_log(double Lc)

Definition: csp.c:198

@ AVCOL_TRC_LOG

"Logarithmic transfer characteristic (100:1 range)"

Definition: pixfmt.h:590

trc_smpte_st2084

static double trc_smpte_st2084(double Lc)

Definition: csp.c:239

static AVRational av_make_q(int num, int den)

Create an AVRational.

Definition: rational.h:71

av_csp_approximate_trc_gamma

double av_csp_approximate_trc_gamma(enum AVColorTransferCharacteristic trc)

Determine a suitable 'gamma' value to match the supplied AVColorTransferCharacteristic.

Definition: csp.c:149

AVPrimaryCoefficients::g

AVCIExy g

Definition: csp.h:65

static av_always_inline int diff(const struct color_info *a, const struct color_info *b, const int trans_thresh)

Definition: vf_paletteuse.c:164

a

The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a

Definition: undefined.txt:41

AVCOL_TRC_BT709

@ AVCOL_TRC_BT709

also ITU-R BT1361

Definition: pixfmt.h:582

AVCOL_SPC_SMPTE240M

@ AVCOL_SPC_SMPTE240M

derived from 170M primaries and D65 white point, 170M is derived from BT470 System M's primaries

Definition: pixfmt.h:617

av_csp_trc_function

double(* av_csp_trc_function)(double)

Function pointer representing a double -> double transfer function that performs an EOTF transfer inv...

Definition: csp.h:87

AVCOL_SPC_BT2020_NCL

@ AVCOL_SPC_BT2020_NCL

ITU-R BT2020 non-constant luminance system.

Definition: pixfmt.h:620

AVColorSpace

YUV colorspace type.

Definition: pixfmt.h:609

static double trc_bt709(double Lc)

Definition: csp.c:163

float delta

Definition: vorbis_enc_data.h:430

av_always_inline

#define av_always_inline

Definition: attributes.h:49

static int av_cmp_q(AVRational a, AVRational b)

Compare two rationals.

Definition: rational.h:89

AVCOL_PRI_BT470M

@ AVCOL_PRI_BT470M

also FCC Title 47 Code of Federal Regulations 73.682 (a)(20)

Definition: pixfmt.h:560

#define WP_E

Definition: csp.c:74

#define AVR(d)

Definition: csp.c:38

AVRational y

Definition: csp.h:57

static double trc_linear(double Lc)

Definition: csp.c:193

#define WP_DCI

Definition: csp.c:73

static const uint64_t c2

Definition: murmur3.c:53

AVCOL_TRC_ARIB_STD_B67

@ AVCOL_TRC_ARIB_STD_B67

ARIB STD-B67, known as "Hybrid log-gamma".

Definition: pixfmt.h:601

static double trc_gamma28(double Lc)

Definition: csp.c:178

@ AVCOL_SPC_FCC

FCC Title 47 Code of Federal Regulations 73.682 (a)(20)

Definition: pixfmt.h:614

static int ref[MAX_W *MAX_W]

Definition: jpeg2000dwt.c:112

L

#define L(x)

Definition: vpx_arith.h:36

AVCOL_TRC_SMPTE170M

@ AVCOL_TRC_SMPTE170M

also ITU-R BT601-6 525 or 625 / ITU-R BT1358 525 or 625 / ITU-R BT1700 NTSC

Definition: pixfmt.h:587

static double trc_log_sqrt(double Lc)

Definition: csp.c:203

AVCOL_PRI_SMPTE432

@ AVCOL_PRI_SMPTE432

SMPTE ST 432-1 (2010) / P3 D65 / Display P3.

Definition: pixfmt.h:570

AVRational av_add_q(AVRational b, AVRational c)

Add two rationals.

Definition: rational.c:93

AVColorPrimariesDesc::prim

AVPrimaryCoefficients prim

Definition: csp.h:80

luma_coefficients

static const struct AVLumaCoefficients luma_coefficients[AVCOL_SPC_NB]

Definition: csp.c:46

AVCOL_TRC_SMPTE428

@ AVCOL_TRC_SMPTE428

SMPTE ST 428-1.

Definition: pixfmt.h:599

trc_arib_std_b67

static double trc_arib_std_b67(double Lc)

Definition: csp.c:261

trc_smpte_st428_1

static double trc_smpte_st428_1(double Lc)

Definition: csp.c:254

AVCOL_SPC_BT709

@ AVCOL_SPC_BT709

also ITU-R BT1361 / IEC 61966-2-4 xvYCC709 / derived in SMPTE RP 177 Annex B

Definition: pixfmt.h:611

trc_iec61966_2_4

static double trc_iec61966_2_4(double Lc)

Definition: csp.c:209

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