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FFmpeg/libavutil/csp.h
Leo Izen d42b410e05 avutil/csp: create public API for colorspace structs
This commit moves some of the functionality from avfilter/colorspace
into avutil/csp and exposes it as a public API so it can be used by
libavcodec and/or libavformat. It also converts those structs from
double values to AVRational to make regression testing easier and
more consistent.

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
2022-06-01 13:52:38 -04:00

107 lines
3.3 KiB
C

/*
* Copyright (c) 2016 Ronald S. Bultje <rsbultje@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.
* @author Ronald S. Bultje <rsbultje@gmail.com>
* @author Leo Izen <leo.izen@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;
/**
* 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);
/**
* @}
*/
#endif /* AVUTIL_CSP_H */