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+/*
+ * 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 */