lut3d.h

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/*
 * Copyright (C) 2024 Niklas Haas
 *
 * 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 SWSCALE_LUT3D_H
#define SWSCALE_LUT3D_H
 
#include <stdint.h>
 
#include "libavutil/csp.h"
#include "libavutil/pixfmt.h"
 
#include "cms.h"
#include "csputils.h"
#include "format.h"
 
enum {
    /* Input LUT size. This is only calculated once. */
    INPUT_LUT_BITS = 6,
    INPUT_LUT_SIZE = (1 << INPUT_LUT_BITS) + 1, /* +1 to simplify interpolation */
 
    /* Tone mapping LUT size. This is regenerated possibly per frame. */
    TONE_LUT_BITS = 8,
    TONE_LUT_SIZE = (1 << TONE_LUT_BITS) + 1,
 
    /* Output LUT size (for dynamic tone mapping). This is only calculated once. */
    OUTPUT_LUT_BITS_I  = 6,
    OUTPUT_LUT_BITS_PT = 7,
 
    OUTPUT_LUT_SIZE_I  = (1 << OUTPUT_LUT_BITS_I)  + 1,
    OUTPUT_LUT_SIZE_PT = (1 << OUTPUT_LUT_BITS_PT) + 1,
};
 
typedef struct SwsLut3D {
    SwsColorMap map;
    bool dynamic;
 
    /* Gamut mapping 3DLUT(s) */
    v3u16_t  input[INPUT_LUT_SIZE][INPUT_LUT_SIZE][INPUT_LUT_SIZE];
    v3u16_t output[OUTPUT_LUT_SIZE_PT][OUTPUT_LUT_SIZE_PT][OUTPUT_LUT_SIZE_I];
 
    /* Split tone mapping LUT (for dynamic tone mapping) */
    v2u16_t tone_map[TONE_LUT_SIZE + 1]; /* new luma, desaturation */
} SwsLut3D;
 
/**
 * Allocates a refstruct. Note that the LUT contents are not initialized.
 */
SwsLut3D *ff_sws_lut3d_alloc(void);
 
/**
 * Recalculate the (static) 3DLUT state with new settings. This will recompute
 * everything. To only update per-frame tone mapping state, instead call
 * ff_sws_lut3d_update().
 *
 * Returns 0 or a negative error code.
 */
int ff_sws_lut3d_generate(SwsLut3D *lut3d, const SwsColorMap *map);
 
/**
 * Update the tone mapping state. This will only use per-frame metadata. The
 * static metadata is ignored.
 */
void ff_sws_lut3d_update(SwsLut3D *lut3d, const SwsColor *new_src);
 
/**
 * Applies a color transformation to a plane in RGBA64 format.
 */
void ff_sws_lut3d_apply_rgba64(const SwsLut3D *lut3d, const uint8_t *in,
                               int in_stride, uint8_t *out, int out_stride,
                               int w, int h);
 
#endif /* SWSCALE_LUT3D_H */