2e674780b7
Logic is, for the most part, a straight port of similar logic in liplacebo's colorspace.c, with some general edits and refactors.
114 lines
3.5 KiB
C
114 lines
3.5 KiB
C
/*
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* Copyright (C) 2024 Niklas Haas
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef SWSCALE_CSPUTILS_H
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#define SWSCALE_CSPUTILS_H
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#include <stdint.h>
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#include <stdbool.h>
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#include <math.h>
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#include "libavutil/attributes.h"
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#include "libavutil/common.h"
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#include "libavutil/csp.h"
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#include "libavutil/pixfmt.h"
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/* Shared constants and helpers for colorspace mapping */
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#define fmixf(a, b, x) ((b) * (x) + (a) * (1 - (x)))
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static inline float smoothstepf(float edge0, float edge1, float x)
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{
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if (edge0 == edge1)
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return x >= edge0;
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x = (x - edge0) / (edge1 - edge0);
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x = av_clipf(x, 0.0f, 1.0f);
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return x * x * (3.0f - 2.0f * x);
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}
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/* 3x3 matrix math */
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typedef struct SwsMatrix3x3 {
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float m[3][3];
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} SwsMatrix3x3;
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void ff_sws_matrix3x3_mul(SwsMatrix3x3 *a, const SwsMatrix3x3 *b);
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void ff_sws_matrix3x3_rmul(const SwsMatrix3x3 *a, SwsMatrix3x3 *b);
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void ff_sws_matrix3x3_invert(SwsMatrix3x3 *mat);
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void ff_sws_matrix3x3_apply(const SwsMatrix3x3 *mat, float vec[3]);
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SwsMatrix3x3 ff_sws_ipt_rgb2lms(const AVColorPrimariesDesc *prim);
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SwsMatrix3x3 ff_sws_ipt_lms2rgb(const AVColorPrimariesDesc *prim);
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/* Converts to/from XYZ (relative to the given white point, no adaptation) */
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SwsMatrix3x3 ff_sws_rgb2xyz(const AVColorPrimariesDesc *prim);
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SwsMatrix3x3 ff_sws_xyz2rgb(const AVColorPrimariesDesc *prim);
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/* Returns an RGB -> RGB adaptation matrix */
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SwsMatrix3x3 ff_sws_get_adaptation(const AVPrimaryCoefficients *prim,
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AVWhitepointCoefficients from,
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AVWhitepointCoefficients to);
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/* Integer math definitions / helpers */
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typedef struct v3u8_t {
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uint8_t x, y, z;
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} v3u8_t;
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typedef struct v2u16_t {
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uint16_t x, y;
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} v2u16_t;
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typedef struct v3u16_t {
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uint16_t x, y, z;
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} v3u16_t;
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/* Fast perceptual quantizer */
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static const float PQ_M1 = 2610./4096 * 1./4,
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PQ_M2 = 2523./4096 * 128,
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PQ_C1 = 3424./4096,
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PQ_C2 = 2413./4096 * 32,
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PQ_C3 = 2392./4096 * 32;
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enum { PQ_LUT_SIZE = 1024 };
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extern const float ff_pq_eotf_lut[PQ_LUT_SIZE+1];
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static inline float pq_eotf(float x)
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{
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float idxf = av_clipf(x, 0.0f, 1.0f) * (PQ_LUT_SIZE - 1);
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int ipart = floorf(idxf);
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float fpart = idxf - ipart;
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return fmixf(ff_pq_eotf_lut[ipart], ff_pq_eotf_lut[ipart + 1], fpart);
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}
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static inline float pq_oetf(float x)
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{
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x = powf(fmaxf(x * 1e-4f, 0.0f), PQ_M1);
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x = (PQ_C1 + PQ_C2 * x) / (1.0f + PQ_C3 * x);
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return powf(x, PQ_M2);
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}
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/* Misc colorspace math / helpers */
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/**
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* Returns true if 'b' is entirely contained in 'a'. Useful for figuring out if
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* colorimetric clipping will occur or not.
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*/
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bool ff_prim_superset(const AVPrimaryCoefficients *a, const AVPrimaryCoefficients *b);
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#endif /* SWSCALE_CSPUTILS_H */
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