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
|
/*
* Copyright (c) 2015 Kevin Wheatley <kevin.j.wheatley@gmail.com>
* Copyright (c) 2016 Ronald S. Bultje <rsbultje@gmail.com>
* Copyright (c) 2023 Leo Izen <leo.izen@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVUTIL_CSP_H
#define AVUTIL_CSP_H
#include "pixfmt.h"
#include "rational.h"
/**
* @file
* Colorspace value utility functions for libavutil.
* @ingroup lavu_math_csp
* @author Ronald S. Bultje <rsbultje@gmail.com>
* @author Leo Izen <leo.izen@gmail.com>
* @author Kevin Wheatley <kevin.j.wheatley@gmail.com>
*/
/**
* @defgroup lavu_math_csp Colorspace Utility
* @ingroup lavu_math
* @{
*/
/**
* Struct containing luma coefficients to be used for RGB to YUV/YCoCg, or similar
* calculations.
*/
typedef struct AVLumaCoefficients {
AVRational cr, cg, cb;
} AVLumaCoefficients;
/**
* Struct containing chromaticity x and y values for the standard CIE 1931
* chromaticity definition.
*/
typedef struct AVCIExy {
AVRational x, y;
} AVCIExy;
/**
* Struct defining the red, green, and blue primary locations in terms of CIE
* 1931 chromaticity x and y.
*/
typedef struct AVPrimaryCoefficients {
AVCIExy r, g, b;
} AVPrimaryCoefficients;
/**
* Struct defining white point location in terms of CIE 1931 chromaticity x
* and y.
*/
typedef AVCIExy AVWhitepointCoefficients;
/**
* Struct that contains both white point location and primaries location, providing
* the complete description of a color gamut.
*/
typedef struct AVColorPrimariesDesc {
AVWhitepointCoefficients wp;
AVPrimaryCoefficients prim;
} AVColorPrimariesDesc;
/**
* Function pointer representing a double -> double transfer function that performs
* an EOTF transfer inversion. This function outputs linear light.
*/
typedef double (*av_csp_trc_function)(double);
/**
* Retrieves the Luma coefficients necessary to construct a conversion matrix
* from an enum constant describing the colorspace.
* @param csp An enum constant indicating YUV or similar colorspace.
* @return The Luma coefficients associated with that colorspace, or NULL
* if the constant is unknown to libavutil.
*/
const AVLumaCoefficients *av_csp_luma_coeffs_from_avcsp(enum AVColorSpace csp);
/**
* Retrieves a complete gamut description from an enum constant describing the
* color primaries.
* @param prm An enum constant indicating primaries
* @return A description of the colorspace gamut associated with that enum
* constant, or NULL if the constant is unknown to libavutil.
*/
const AVColorPrimariesDesc *av_csp_primaries_desc_from_id(enum AVColorPrimaries prm);
/**
* Detects which enum AVColorPrimaries constant corresponds to the given complete
* gamut description.
* @see enum AVColorPrimaries
* @param prm A description of the colorspace gamut
* @return The enum constant associated with this gamut, or
* AVCOL_PRI_UNSPECIFIED if no clear match can be idenitified.
*/
enum AVColorPrimaries av_csp_primaries_id_from_desc(const AVColorPrimariesDesc *prm);
/**
* Determine a suitable 'gamma' value to match the supplied
* AVColorTransferCharacteristic.
*
* See Apple Technical Note TN2257 (https://developer.apple.com/library/mac/technotes/tn2257/_index.html)
*
* This function returns the gamma exponent for the OETF. For example, sRGB is approximated
* by gamma 2.2, not by gamma 0.45455.
*
* @return Will return an approximation to the simple gamma function matching
* the supplied Transfer Characteristic, Will return 0.0 for any
* we cannot reasonably match against.
*/
double av_csp_approximate_trc_gamma(enum AVColorTransferCharacteristic trc);
/**
* Determine the function needed to apply the given
* AVColorTransferCharacteristic to linear input.
*
* The function returned should expect a nominal domain and range of [0.0-1.0]
* values outside of this range maybe valid depending on the chosen
* characteristic function.
*
* @return Will return pointer to the function matching the
* supplied Transfer Characteristic. If unspecified will
* return NULL:
*/
av_csp_trc_function av_csp_trc_func_from_id(enum AVColorTransferCharacteristic trc);
/**
* @}
*/
#endif /* AVUTIL_CSP_H */
|
