1 /*
2 * Copyright (c) 2016 Ronald S. Bultje <rsbultje@gmail.com>
3 * This file is part of FFmpeg.
4 *
5 * FFmpeg is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * FFmpeg is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with FFmpeg; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20 /**
21 * @file Colorspace functions for libavutil
22 * @author Ronald S. Bultje <rsbultje@gmail.com>
23 * @author Leo Izen <leo.izen@gmail.com>
24 */
25
26 #include <stdlib.h>
27
28 #include "attributes.h"
29 #include "csp.h"
30 #include "pixfmt.h"
31 #include "rational.h"
32
33 #define AVR(d) { (int)(d * 100000 + 0.5), 100000 }
34
35 /*
36 * All constants explained in e.g. https://linuxtv.org/downloads/v4l-dvb-apis/ch02s06.html
37 * The older ones (bt470bg/m) are also explained in their respective ITU docs
38 * (e.g. https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.470-5-199802-S!!PDF-E.pdf)
39 * whereas the newer ones can typically be copied directly from wikipedia :)
40 */
41 static const struct AVLumaCoefficients luma_coefficients[AVCOL_SPC_NB] = {
42 [AVCOL_SPC_FCC] = { AVR(0.30), AVR(0.59), AVR(0.11) },
43 [AVCOL_SPC_BT470BG] = { AVR(0.299), AVR(0.587), AVR(0.114) },
44 [AVCOL_SPC_SMPTE170M] = { AVR(0.299), AVR(0.587), AVR(0.114) },
45 [AVCOL_SPC_BT709] = { AVR(0.2126), AVR(0.7152), AVR(0.0722) },
46 [AVCOL_SPC_SMPTE240M] = { AVR(0.212), AVR(0.701), AVR(0.087) },
47 [AVCOL_SPC_YCOCG] = { AVR(0.25), AVR(0.5), AVR(0.25) },
48 [AVCOL_SPC_RGB] = { AVR(1), AVR(1), AVR(1) },
49 [AVCOL_SPC_BT2020_NCL] = { AVR(0.2627), AVR(0.6780), AVR(0.0593) },
50 [AVCOL_SPC_BT2020_CL] = { AVR(0.2627), AVR(0.6780), AVR(0.0593) },
51 };
52
av_csp_luma_coeffs_from_avcsp(enum AVColorSpace csp)53 const struct AVLumaCoefficients *av_csp_luma_coeffs_from_avcsp(enum AVColorSpace csp)
54 {
55 const AVLumaCoefficients *coeffs;
56
57 if (csp >= AVCOL_SPC_NB)
58 return NULL;
59 coeffs = &luma_coefficients[csp];
60 if (!coeffs->cr.num)
61 return NULL;
62
63 return coeffs;
64 }
65
66 #define WP_D65 { AVR(0.3127), AVR(0.3290) }
67 #define WP_C { AVR(0.3100), AVR(0.3160) }
68 #define WP_DCI { AVR(0.3140), AVR(0.3510) }
69 #define WP_E { {1, 3}, {1, 3} }
70
71 static const AVColorPrimariesDesc color_primaries[AVCOL_PRI_NB] = {
72 [AVCOL_PRI_BT709] = { WP_D65, { { AVR(0.640), AVR(0.330) }, { AVR(0.300), AVR(0.600) }, { AVR(0.150), AVR(0.060) } } },
73 [AVCOL_PRI_BT470M] = { WP_C, { { AVR(0.670), AVR(0.330) }, { AVR(0.210), AVR(0.710) }, { AVR(0.140), AVR(0.080) } } },
74 [AVCOL_PRI_BT470BG] = { WP_D65, { { AVR(0.640), AVR(0.330) }, { AVR(0.290), AVR(0.600) }, { AVR(0.150), AVR(0.060) } } },
75 [AVCOL_PRI_SMPTE170M] = { WP_D65, { { AVR(0.630), AVR(0.340) }, { AVR(0.310), AVR(0.595) }, { AVR(0.155), AVR(0.070) } } },
76 [AVCOL_PRI_SMPTE240M] = { WP_D65, { { AVR(0.630), AVR(0.340) }, { AVR(0.310), AVR(0.595) }, { AVR(0.155), AVR(0.070) } } },
77 [AVCOL_PRI_SMPTE428] = { WP_E, { { AVR(0.735), AVR(0.265) }, { AVR(0.274), AVR(0.718) }, { AVR(0.167), AVR(0.009) } } },
78 [AVCOL_PRI_SMPTE431] = { WP_DCI, { { AVR(0.680), AVR(0.320) }, { AVR(0.265), AVR(0.690) }, { AVR(0.150), AVR(0.060) } } },
79 [AVCOL_PRI_SMPTE432] = { WP_D65, { { AVR(0.680), AVR(0.320) }, { AVR(0.265), AVR(0.690) }, { AVR(0.150), AVR(0.060) } } },
80 [AVCOL_PRI_FILM] = { WP_C, { { AVR(0.681), AVR(0.319) }, { AVR(0.243), AVR(0.692) }, { AVR(0.145), AVR(0.049) } } },
81 [AVCOL_PRI_BT2020] = { WP_D65, { { AVR(0.708), AVR(0.292) }, { AVR(0.170), AVR(0.797) }, { AVR(0.131), AVR(0.046) } } },
82 [AVCOL_PRI_JEDEC_P22] = { WP_D65, { { AVR(0.630), AVR(0.340) }, { AVR(0.295), AVR(0.605) }, { AVR(0.155), AVR(0.077) } } },
83 };
84
av_csp_primaries_desc_from_id(enum AVColorPrimaries prm)85 const AVColorPrimariesDesc *av_csp_primaries_desc_from_id(enum AVColorPrimaries prm)
86 {
87 const AVColorPrimariesDesc *p;
88
89 if (prm >= AVCOL_PRI_NB)
90 return NULL;
91 p = &color_primaries[prm];
92 if (!p->prim.r.x.num)
93 return NULL;
94
95 return p;
96 }
97
abs_sub_q(AVRational r1,AVRational r2)98 static av_always_inline AVRational abs_sub_q(AVRational r1, AVRational r2)
99 {
100 AVRational diff = av_sub_q(r1, r2);
101 /* denominator assumed to be positive */
102 return av_make_q(abs(diff.num), diff.den);
103 }
104
av_csp_primaries_id_from_desc(const AVColorPrimariesDesc * prm)105 enum AVColorPrimaries av_csp_primaries_id_from_desc(const AVColorPrimariesDesc *prm)
106 {
107 AVRational delta;
108
109 for (enum AVColorPrimaries p = 0; p < AVCOL_PRI_NB; p++) {
110 const AVColorPrimariesDesc *ref = &color_primaries[p];
111 if (!ref->prim.r.x.num)
112 continue;
113
114 delta = abs_sub_q(prm->prim.r.x, ref->prim.r.x);
115 delta = av_add_q(delta, abs_sub_q(prm->prim.r.y, ref->prim.r.y));
116 delta = av_add_q(delta, abs_sub_q(prm->prim.g.x, ref->prim.g.x));
117 delta = av_add_q(delta, abs_sub_q(prm->prim.g.y, ref->prim.g.y));
118 delta = av_add_q(delta, abs_sub_q(prm->prim.b.x, ref->prim.b.x));
119 delta = av_add_q(delta, abs_sub_q(prm->prim.b.y, ref->prim.b.y));
120 delta = av_add_q(delta, abs_sub_q(prm->wp.x, ref->wp.x));
121 delta = av_add_q(delta, abs_sub_q(prm->wp.y, ref->wp.y));
122
123 if (av_cmp_q(delta, av_make_q(1, 1000)) < 0)
124 return p;
125 }
126
127 return AVCOL_PRI_UNSPECIFIED;
128 }
129