/*
 * Copyright (c) 2013 Clément Bœsch
 *
 * 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
 */

/**
 * @file
 * 3D Lookup table filter
 */

#include "libavutil/opt.h"
#include "libavutil/file.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/avassert.h"
#include "libavutil/pixdesc.h"
#include "libavutil/avstring.h"
#include "avfilter.h"
#include "drawutils.h"
#include "dualinput.h"
#include "formats.h"
#include "internal.h"
#include "video.h"

#define R 0
#define G 1
#define B 2
#define A 3

enum interp_mode {
    INTERPOLATE_NEAREST,
    INTERPOLATE_TRILINEAR,
    INTERPOLATE_TETRAHEDRAL,
    NB_INTERP_MODE
};

struct rgbvec {
    float r, g, b;
};

/* 3D LUT don't often go up to level 32, but it is common to have a Hald CLUT
 * of 512x512 (64x64x64) */
#define MAX_LEVEL 64

typedef struct LUT3DContext {
    const AVClass *class;
    enum interp_mode interpolation;
    char *file;
    uint8_t rgba_map[4];
    int step;
    avfilter_action_func *interp;
    struct rgbvec lut[MAX_LEVEL][MAX_LEVEL][MAX_LEVEL];
    int lutsize;
#if CONFIG_HALDCLUT_FILTER
    uint8_t clut_rgba_map[4];
    int clut_step;
    int clut_is16bit;
    int clut_width;
    FFDualInputContext dinput;
#endif
} LUT3DContext;

typedef struct ThreadData {
    AVFrame *in, *out;
} ThreadData;

#define OFFSET(x) offsetof(LUT3DContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

#define COMMON_OPTIONS \
    { "interp", "select interpolation mode", OFFSET(interpolation), AV_OPT_TYPE_INT, {.i64=INTERPOLATE_TETRAHEDRAL}, 0, NB_INTERP_MODE-1, FLAGS, "interp_mode" }, \
        { "nearest",     "use values from the nearest defined points",            0, AV_OPT_TYPE_CONST, {.i64=INTERPOLATE_NEAREST},     INT_MIN, INT_MAX, FLAGS, "interp_mode" }, \
        { "trilinear",   "interpolate values using the 8 points defining a cube", 0, AV_OPT_TYPE_CONST, {.i64=INTERPOLATE_TRILINEAR},   INT_MIN, INT_MAX, FLAGS, "interp_mode" }, \
        { "tetrahedral", "interpolate values using a tetrahedron",                0, AV_OPT_TYPE_CONST, {.i64=INTERPOLATE_TETRAHEDRAL}, INT_MIN, INT_MAX, FLAGS, "interp_mode" }, \
    { NULL }

static inline float lerpf(float v0, float v1, float f)
{
    return v0 + (v1 - v0) * f;
}

static inline struct rgbvec lerp(const struct rgbvec *v0, const struct rgbvec *v1, float f)
{
    struct rgbvec v = {
        lerpf(v0->r, v1->r, f), lerpf(v0->g, v1->g, f), lerpf(v0->b, v1->b, f)
    };
    return v;
}

#define NEAR(x) ((int)((x) + .5))
#define PREV(x) ((int)(x))
#define NEXT(x) (FFMIN((int)(x) + 1, lut3d->lutsize - 1))

/**
 * Get the nearest defined point
 */
static inline struct rgbvec interp_nearest(const LUT3DContext *lut3d,
                                           const struct rgbvec *s)
{
    return lut3d->lut[NEAR(s->r)][NEAR(s->g)][NEAR(s->b)];
}

/**
 * Interpolate using the 8 vertices of a cube
 * @see https://en.wikipedia.org/wiki/Trilinear_interpolation
 */
static inline struct rgbvec interp_trilinear(const LUT3DContext *lut3d,
                                             const struct rgbvec *s)
{
    const int prev[] = {PREV(s->r), PREV(s->g), PREV(s->b)};
    const int next[] = {NEXT(s->r), NEXT(s->g), NEXT(s->b)};
    const struct rgbvec d = {s->r - prev[0], s->g - prev[1], s->b - prev[2]};
    const struct rgbvec c000 = lut3d->lut[prev[0]][prev[1]][prev[2]];
    const struct rgbvec c001 = lut3d->lut[prev[0]][prev[1]][next[2]];
    const struct rgbvec c010 = lut3d->lut[prev[0]][next[1]][prev[2]];
    const struct rgbvec c011 = lut3d->lut[prev[0]][next[1]][next[2]];
    const struct rgbvec c100 = lut3d->lut[next[0]][prev[1]][prev[2]];
    const struct rgbvec c101 = lut3d->lut[next[0]][prev[1]][next[2]];
    const struct rgbvec c110 = lut3d->lut[next[0]][next[1]][prev[2]];
    const struct rgbvec c111 = lut3d->lut[next[0]][next[1]][next[2]];
    const struct rgbvec c00  = lerp(&c000, &c100, d.r);
    const struct rgbvec c10  = lerp(&c010, &c110, d.r);
    const struct rgbvec c01  = lerp(&c001, &c101, d.r);
    const struct rgbvec c11  = lerp(&c011, &c111, d.r);
    const struct rgbvec c0   = lerp(&c00,  &c10,  d.g);
    const struct rgbvec c1   = lerp(&c01,  &c11,  d.g);
    const struct rgbvec c    = lerp(&c0,   &c1,   d.b);
    return c;
}

/**
 * Tetrahedral interpolation. Based on code found in Truelight Software Library paper.
 * @see http://www.filmlight.ltd.uk/pdf/whitepapers/FL-TL-TN-0057-SoftwareLib.pdf
 */
static inline struct rgbvec interp_tetrahedral(const LUT3DContext *lut3d,
                                               const struct rgbvec *s)
{
    const int prev[] = {PREV(s->r), PREV(s->g), PREV(s->b)};
    const int next[] = {NEXT(s->r), NEXT(s->g), NEXT(s->b)};
    const struct rgbvec d = {s->r - prev[0], s->g - prev[1], s->b - prev[2]};
    const struct rgbvec c000 = lut3d->lut[prev[0]][prev[1]][prev[2]];
    const struct rgbvec c111 = lut3d->lut[next[0]][next[1]][next[2]];
    struct rgbvec c;
    if (d.r > d.g) {
        if (d.g > d.b) {
            const struct rgbvec c100 = lut3d->lut[next[0]][prev[1]][prev[2]];
            const struct rgbvec c110 = lut3d->lut[next[0]][next[1]][prev[2]];
            c.r = (1-d.r) * c000.r + (d.r-d.g) * c100.r + (d.g-d.b) * c110.r + (d.b) * c111.r;
            c.g = (1-d.r) * c000.g + (d.r-d.g) * c100.g + (d.g-d.b) * c110.g + (d.b) * c111.g;
            c.b = (1-d.r) * c000.b + (d.r-d.g) * c100.b + (d.g-d.b) * c110.b + (d.b) * c111.b;
        } else if (d.r > d.b) {
            const struct rgbvec c100 = lut3d->lut[next[0]][prev[1]][prev[2]];
            const struct rgbvec c101 = lut3d->lut[next[0]][prev[1]][next[2]];
            c.r = (1-d.r) * c000.r + (d.r-d.b) * c100.r + (d.b-d.g) * c101.r + (d.g) * c111.r;
            c.g = (1-d.r) * c000.g + (d.r-d.b) * c100.g + (d.b-d.g) * c101.g + (d.g) * c111.g;
            c.b = (1-d.r) * c000.b + (d.r-d.b) * c100.b + (d.b-d.g) * c101.b + (d.g) * c111.b;
        } else {
            const struct rgbvec c001 = lut3d->lut[prev[0]][prev[1]][next[2]];
            const struct rgbvec c101 = lut3d->lut[next[0]][prev[1]][next[2]];
            c.r = (1-d.b) * c000.r + (d.b-d.r) * c001.r + (d.r-d.g) * c101.r + (d.g) * c111.r;
            c.g = (1-d.b) * c000.g + (d.b-d.r) * c001.g + (d.r-d.g) * c101.g + (d.g) * c111.g;
            c.b = (1-d.b) * c000.b + (d.b-d.r) * c001.b + (d.r-d.g) * c101.b + (d.g) * c111.b;
        }
    } else {
        if (d.b > d.g) {
            const struct rgbvec c001 = lut3d->lut[prev[0]][prev[1]][next[2]];
            const struct rgbvec c011 = lut3d->lut[prev[0]][next[1]][next[2]];
            c.r = (1-d.b) * c000.r + (d.b-d.g) * c001.r + (d.g-d.r) * c011.r + (d.r) * c111.r;
            c.g = (1-d.b) * c000.g + (d.b-d.g) * c001.g + (d.g-d.r) * c011.g + (d.r) * c111.g;
            c.b = (1-d.b) * c000.b + (d.b-d.g) * c001.b + (d.g-d.r) * c011.b + (d.r) * c111.b;
        } else if (d.b > d.r) {
            const struct rgbvec c010 = lut3d->lut[prev[0]][next[1]][prev[2]];
            const struct rgbvec c011 = lut3d->lut[prev[0]][next[1]][next[2]];
            c.r = (1-d.g) * c000.r + (d.g-d.b) * c010.r + (d.b-d.r) * c011.r + (d.r) * c111.r;
            c.g = (1-d.g) * c000.g + (d.g-d.b) * c010.g + (d.b-d.r) * c011.g + (d.r) * c111.g;
            c.b = (1-d.g) * c000.b + (d.g-d.b) * c010.b + (d.b-d.r) * c011.b + (d.r) * c111.b;
        } else {
            const struct rgbvec c010 = lut3d->lut[prev[0]][next[1]][prev[2]];
            const struct rgbvec c110 = lut3d->lut[next[0]][next[1]][prev[2]];
            c.r = (1-d.g) * c000.r + (d.g-d.r) * c010.r + (d.r-d.b) * c110.r + (d.b) * c111.r;
            c.g = (1-d.g) * c000.g + (d.g-d.r) * c010.g + (d.r-d.b) * c110.g + (d.b) * c111.g;
            c.b = (1-d.g) * c000.b + (d.g-d.r) * c010.b + (d.r-d.b) * c110.b + (d.b) * c111.b;
        }
    }
    return c;
}

#define DEFINE_INTERP_FUNC(name, nbits)                                                             \
static int interp_##nbits##_##name(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)         \
{                                                                                                   \
    int x, y;                                                                                       \
    const LUT3DContext *lut3d = ctx->priv;                                                          \
    const ThreadData *td = arg;                                                                     \
    const AVFrame *in  = td->in;                                                                    \
    const AVFrame *out = td->out;                                                                   \
    const int direct = out == in;                                                                   \
    const int step = lut3d->step;                                                                   \
    const uint8_t r = lut3d->rgba_map[R];                                                           \
    const uint8_t g = lut3d->rgba_map[G];                                                           \
    const uint8_t b = lut3d->rgba_map[B];                                                           \
    const uint8_t a = lut3d->rgba_map[A];                                                           \
    const int slice_start = (in->height *  jobnr   ) / nb_jobs;                                     \
    const int slice_end   = (in->height * (jobnr+1)) / nb_jobs;                                     \
    uint8_t       *dstrow = out->data[0] + slice_start * out->linesize[0];                          \
    const uint8_t *srcrow = in ->data[0] + slice_start * in ->linesize[0];                          \
    const float scale = (1. / ((1<<nbits) - 1)) * (lut3d->lutsize - 1);                             \
                                                                                                    \
    for (y = slice_start; y < slice_end; y++) {                                                     \
        uint##nbits##_t *dst = (uint##nbits##_t *)dstrow;                                           \
        const uint##nbits##_t *src = (const uint##nbits##_t *)srcrow;                               \
        for (x = 0; x < in->width * step; x += step) {                                              \
            const struct rgbvec scaled_rgb = {src[x + r] * scale,                                   \
                                              src[x + g] * scale,                                   \
                                              src[x + b] * scale};                                  \
            struct rgbvec vec = interp_##name(lut3d, &scaled_rgb);                                  \
            dst[x + r] = av_clip_uint##nbits(vec.r * (float)((1<<nbits) - 1));                      \
            dst[x + g] = av_clip_uint##nbits(vec.g * (float)((1<<nbits) - 1));                      \
            dst[x + b] = av_clip_uint##nbits(vec.b * (float)((1<<nbits) - 1));                      \
            if (!direct && step == 4)                                                               \
                dst[x + a] = src[x + a];                                                            \
        }                                                                                           \
        dstrow += out->linesize[0];                                                                 \
        srcrow += in ->linesize[0];                                                                 \
    }                                                                                               \
    return 0;                                                                                       \
}

DEFINE_INTERP_FUNC(nearest,     8)
DEFINE_INTERP_FUNC(trilinear,   8)
DEFINE_INTERP_FUNC(tetrahedral, 8)

DEFINE_INTERP_FUNC(nearest,     16)
DEFINE_INTERP_FUNC(trilinear,   16)
DEFINE_INTERP_FUNC(tetrahedral, 16)

#define MAX_LINE_SIZE 512

static int skip_line(const char *p)
{
    while (*p && av_isspace(*p))
        p++;
    return !*p || *p == '#';
}

#define NEXT_LINE(loop_cond) do {                           \
    if (!fgets(line, sizeof(line), f)) {                    \
        av_log(ctx, AV_LOG_ERROR, "Unexpected EOF\n");      \
        return AVERROR_INVALIDDATA;                         \
    }                                                       \
} while (loop_cond)

/* Basically r g and b float values on each line, with a facultative 3DLUTSIZE
 * directive; seems to be generated by Davinci */
static int parse_dat(AVFilterContext *ctx, FILE *f)
{
    LUT3DContext *lut3d = ctx->priv;
    char line[MAX_LINE_SIZE];
    int i, j, k, size;

    lut3d->lutsize = size = 33;

    NEXT_LINE(skip_line(line));
    if (!strncmp(line, "3DLUTSIZE ", 10)) {
        size = strtol(line + 10, NULL, 0);
        if (size < 2 || size > MAX_LEVEL) {
            av_log(ctx, AV_LOG_ERROR, "Too large or invalid 3D LUT size\n");
            return AVERROR(EINVAL);
        }
        lut3d->lutsize = size;
        NEXT_LINE(skip_line(line));
    }
    for (k = 0; k < size; k++) {
        for (j = 0; j < size; j++) {
            for (i = 0; i < size; i++) {
                struct rgbvec *vec = &lut3d->lut[k][j][i];
                if (k != 0 || j != 0 || i != 0)
                    NEXT_LINE(skip_line(line));
                if (sscanf(line, "%f %f %f", &vec->r, &vec->g, &vec->b) != 3)
                    return AVERROR_INVALIDDATA;
            }
        }
    }
    return 0;
}

/* Iridas format */
static int parse_cube(AVFilterContext *ctx, FILE *f)
{
    LUT3DContext *lut3d = ctx->priv;
    char line[MAX_LINE_SIZE];
    float min[3] = {0.0, 0.0, 0.0};
    float max[3] = {1.0, 1.0, 1.0};

    while (fgets(line, sizeof(line), f)) {
        if (!strncmp(line, "LUT_3D_SIZE ", 12)) {
            int i, j, k;
            const int size = strtol(line + 12, NULL, 0);

            if (size < 2 || size > MAX_LEVEL) {
                av_log(ctx, AV_LOG_ERROR, "Too large or invalid 3D LUT size\n");
                return AVERROR(EINVAL);
            }
            lut3d->lutsize = size;
            for (k = 0; k < size; k++) {
                for (j = 0; j < size; j++) {
                    for (i = 0; i < size; i++) {
                        struct rgbvec *vec = &lut3d->lut[i][j][k];

                        do {
                            NEXT_LINE(0);
                            if (!strncmp(line, "DOMAIN_", 7)) {
                                float *vals = NULL;
                                if      (!strncmp(line + 7, "MIN ", 4)) vals = min;
                                else if (!strncmp(line + 7, "MAX ", 4)) vals = max;
                                if (!vals)
                                    return AVERROR_INVALIDDATA;
                                sscanf(line + 11, "%f %f %f", vals, vals + 1, vals + 2);
                                av_log(ctx, AV_LOG_DEBUG, "min: %f %f %f | max: %f %f %f\n",
                                       min[0], min[1], min[2], max[0], max[1], max[2]);
                                continue;
                            }
                        } while (skip_line(line));
                        if (sscanf(line, "%f %f %f", &vec->r, &vec->g, &vec->b) != 3)
                            return AVERROR_INVALIDDATA;
                        vec->r *= max[0] - min[0];
                        vec->g *= max[1] - min[1];
                        vec->b *= max[2] - min[2];
                    }
                }
            }
            break;
        }
    }
    return 0;
}

/* Assume 17x17x17 LUT with a 16-bit depth
 * FIXME: it seems there are various 3dl formats */
static int parse_3dl(AVFilterContext *ctx, FILE *f)
{
    char line[MAX_LINE_SIZE];
    LUT3DContext *lut3d = ctx->priv;
    int i, j, k;
    const int size = 17;
    const float scale = 16*16*16;

    lut3d->lutsize = size;
    NEXT_LINE(skip_line(line));
    for (k = 0; k < size; k++) {
        for (j = 0; j < size; j++) {
            for (i = 0; i < size; i++) {
                int r, g, b;
                struct rgbvec *vec = &lut3d->lut[k][j][i];

                NEXT_LINE(skip_line(line));
                if (sscanf(line, "%d %d %d", &r, &g, &b) != 3)
                    return AVERROR_INVALIDDATA;
                vec->r = r / scale;
                vec->g = g / scale;
                vec->b = b / scale;
            }
        }
    }
    return 0;
}

/* Pandora format */
static int parse_m3d(AVFilterContext *ctx, FILE *f)
{
    LUT3DContext *lut3d = ctx->priv;
    float scale;
    int i, j, k, size, in = -1, out = -1;
    char line[MAX_LINE_SIZE];
    uint8_t rgb_map[3] = {0, 1, 2};

    while (fgets(line, sizeof(line), f)) {
        if      (!strncmp(line, "in",  2)) in  = strtol(line + 2, NULL, 0);
        else if (!strncmp(line, "out", 3)) out = strtol(line + 3, NULL, 0);
        else if (!strncmp(line, "values", 6)) {
            const char *p = line + 6;
#define SET_COLOR(id) do {                  \
    while (av_isspace(*p))                  \
        p++;                                \
    switch (*p) {                           \
    case 'r': rgb_map[id] = 0; break;       \
    case 'g': rgb_map[id] = 1; break;       \
    case 'b': rgb_map[id] = 2; break;       \
    }                                       \
    while (*p && !av_isspace(*p))           \
        p++;                                \
} while (0)
            SET_COLOR(0);
            SET_COLOR(1);
            SET_COLOR(2);
            break;
        }
    }

    if (in == -1 || out == -1) {
        av_log(ctx, AV_LOG_ERROR, "in and out must be defined\n");
        return AVERROR_INVALIDDATA;
    }
    if (in < 2 || out < 2 ||
        in  > MAX_LEVEL*MAX_LEVEL*MAX_LEVEL ||
        out > MAX_LEVEL*MAX_LEVEL*MAX_LEVEL) {
        av_log(ctx, AV_LOG_ERROR, "invalid in (%d) or out (%d)\n", in, out);
        return AVERROR_INVALIDDATA;
    }
    for (size = 1; size*size*size < in; size++);
    lut3d->lutsize = size;
    scale = 1. / (out - 1);

    for (k = 0; k < size; k++) {
        for (j = 0; j < size; j++) {
            for (i = 0; i < size; i++) {
                struct rgbvec *vec = &lut3d->lut[k][j][i];
                float val[3];

                NEXT_LINE(0);
                if (sscanf(line, "%f %f %f", val, val + 1, val + 2) != 3)
                    return AVERROR_INVALIDDATA;
                vec->r = val[rgb_map[0]] * scale;
                vec->g = val[rgb_map[1]] * scale;
                vec->b = val[rgb_map[2]] * scale;
            }
        }
    }
    return 0;
}

static void set_identity_matrix(LUT3DContext *lut3d, int size)
{
    int i, j, k;
    const float c = 1. / (size - 1);

    lut3d->lutsize = size;
    for (k = 0; k < size; k++) {
        for (j = 0; j < size; j++) {
            for (i = 0; i < size; i++) {
                struct rgbvec *vec = &lut3d->lut[k][j][i];
                vec->r = k * c;
                vec->g = j * c;
                vec->b = i * c;
            }
        }
    }
}

static int query_formats(AVFilterContext *ctx)
{
    static const enum AVPixelFormat pix_fmts[] = {
        AV_PIX_FMT_RGB24,  AV_PIX_FMT_BGR24,
        AV_PIX_FMT_RGBA,   AV_PIX_FMT_BGRA,
        AV_PIX_FMT_ARGB,   AV_PIX_FMT_ABGR,
        AV_PIX_FMT_0RGB,   AV_PIX_FMT_0BGR,
        AV_PIX_FMT_RGB0,   AV_PIX_FMT_BGR0,
        AV_PIX_FMT_RGB48,  AV_PIX_FMT_BGR48,
        AV_PIX_FMT_RGBA64, AV_PIX_FMT_BGRA64,
        AV_PIX_FMT_NONE
    };
    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
    return 0;
}

static int config_input(AVFilterLink *inlink)
{
    int is16bit = 0;
    LUT3DContext *lut3d = inlink->dst->priv;
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);

    switch (inlink->format) {
    case AV_PIX_FMT_RGB48:
    case AV_PIX_FMT_BGR48:
    case AV_PIX_FMT_RGBA64:
    case AV_PIX_FMT_BGRA64:
        is16bit = 1;
    }

    ff_fill_rgba_map(lut3d->rgba_map, inlink->format);
    lut3d->step = av_get_padded_bits_per_pixel(desc) >> (3 + is16bit);

#define SET_FUNC(name) do {                             \
    if (is16bit) lut3d->interp = interp_16_##name;      \
    else         lut3d->interp = interp_8_##name;       \
} while (0)

    switch (lut3d->interpolation) {
    case INTERPOLATE_NEAREST:     SET_FUNC(nearest);        break;
    case INTERPOLATE_TRILINEAR:   SET_FUNC(trilinear);      break;
    case INTERPOLATE_TETRAHEDRAL: SET_FUNC(tetrahedral);    break;
    default:
        av_assert0(0);
    }

    return 0;
}

static AVFrame *apply_lut(AVFilterLink *inlink, AVFrame *in)
{
    AVFilterContext *ctx = inlink->dst;
    LUT3DContext *lut3d = ctx->priv;
    AVFilterLink *outlink = inlink->dst->outputs[0];
    AVFrame *out;
    ThreadData td;

    if (av_frame_is_writable(in)) {
        out = in;
    } else {
        out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
        if (!out) {
            av_frame_free(&in);
            return NULL;
        }
        av_frame_copy_props(out, in);
    }

    td.in  = in;
    td.out = out;
    ctx->internal->execute(ctx, lut3d->interp, &td, NULL, FFMIN(outlink->h, ctx->graph->nb_threads));

    if (out != in)
        av_frame_free(&in);

    return out;
}

static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
    AVFilterLink *outlink = inlink->dst->outputs[0];
    AVFrame *out = apply_lut(inlink, in);
    if (!out)
        return AVERROR(ENOMEM);
    return ff_filter_frame(outlink, out);
}

#if CONFIG_LUT3D_FILTER
static const AVOption lut3d_options[] = {
	{ "file", "set 3D LUT file name", OFFSET(file), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
	COMMON_OPTIONS
};

AVFILTER_DEFINE_CLASS(lut3d);

static av_cold int lut3d_init(AVFilterContext *ctx)
{
    int ret;
    FILE *f;
    const char *ext;
    LUT3DContext *lut3d = ctx->priv;

    if (!lut3d->file) {
        set_identity_matrix(lut3d, 32);
        return 0;
    }

    f = fopen(lut3d->file, "r");
    if (!f) {
		ret = AVERROR(errno);
		av_log(ctx, AV_LOG_ERROR, "%s: %s\n", lut3d->file, av_err2str(ret));
		return ret;
    }

    ext = strrchr(lut3d->file, '.');
    if (!ext) {
        av_log(ctx, AV_LOG_ERROR, "Unable to guess the format from the extension\n");
        ret = AVERROR_INVALIDDATA;
        goto end;
    }
    ext++;

    if (!av_strcasecmp(ext, "dat")) {
        ret = parse_dat(ctx, f);
    } else if (!av_strcasecmp(ext, "3dl")) {
        ret = parse_3dl(ctx, f);
    } else if (!av_strcasecmp(ext, "cube")) {
        ret = parse_cube(ctx, f);
    } else if (!av_strcasecmp(ext, "m3d")) {
        ret = parse_m3d(ctx, f);
    } else {
        av_log(ctx, AV_LOG_ERROR, "Unrecognized '.%s' file type\n", ext);
        ret = AVERROR(EINVAL);
    }

    if (!ret && !lut3d->lutsize) {
        av_log(ctx, AV_LOG_ERROR, "3D LUT is empty\n");
        ret = AVERROR_INVALIDDATA;
    }

end:
    fclose(f);
    return ret;
}

static const AVFilterPad lut3d_inputs[] = {
    {
		.name         = "default",
        .type         = AVMEDIA_TYPE_VIDEO,
        .filter_frame = filter_frame,
        .config_props = config_input,
	},
    { NULL }
};

static const AVFilterPad lut3d_outputs[] = {
     {
		 .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
	 },
     { NULL }
};

AVFilter ff_vf_lut3d = {
	.name          = "lut3d",
    .description   = NULL_IF_CONFIG_SMALL("Adjust colors using a 3D LUT."),
    .priv_size     = sizeof(LUT3DContext),
    .init          = lut3d_init,
    .query_formats = query_formats,
    .inputs        = lut3d_inputs,
    .outputs       = lut3d_outputs,
    .priv_class    = &lut3d_class,
    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
};
#endif

#if CONFIG_HALDCLUT_FILTER

static void update_clut(LUT3DContext *lut3d, const AVFrame *frame)
{
    const uint8_t *data = frame->data[0];
    const int linesize  = frame->linesize[0];
    const int w = lut3d->clut_width;
    const int step = lut3d->clut_step;
    const uint8_t *rgba_map = lut3d->clut_rgba_map;
    const int level = lut3d->lutsize;

#define LOAD_CLUT(nbits) do {                                           \
    int i, j, k, x = 0, y = 0;                                          \
                                                                        \
    for (k = 0; k < level; k++) {                                       \
        for (j = 0; j < level; j++) {                                   \
            for (i = 0; i < level; i++) {                               \
                const uint##nbits##_t *src = (const uint##nbits##_t *)  \
                    (data + y*linesize + x*step);                       \
                struct rgbvec *vec = &lut3d->lut[i][j][k];              \
                vec->r = src[rgba_map[0]] / (float)((1<<(nbits)) - 1);  \
                vec->g = src[rgba_map[1]] / (float)((1<<(nbits)) - 1);  \
                vec->b = src[rgba_map[2]] / (float)((1<<(nbits)) - 1);  \
                if (++x == w) {                                         \
                    x = 0;                                              \
                    y++;                                                \
                }                                                       \
            }                                                           \
        }                                                               \
    }                                                                   \
} while (0)

    if (!lut3d->clut_is16bit) LOAD_CLUT(8);
    else                      LOAD_CLUT(16);
}


static int config_output(AVFilterLink *outlink)
{
    AVFilterContext *ctx = outlink->src;
    LUT3DContext *lut3d = ctx->priv;
    int ret;

    outlink->w = ctx->inputs[0]->w;
    outlink->h = ctx->inputs[0]->h;
    outlink->time_base = ctx->inputs[0]->time_base;
    if ((ret = ff_dualinput_init(ctx, &lut3d->dinput)) < 0)
        return ret;
    return 0;
}

static int filter_frame_hald(AVFilterLink *inlink, AVFrame *inpicref)
{
    LUT3DContext *s = inlink->dst->priv;
    return ff_dualinput_filter_frame(&s->dinput, inlink, inpicref);
}

static int request_frame(AVFilterLink *outlink)
{
    LUT3DContext *s = outlink->src->priv;
    return ff_dualinput_request_frame(&s->dinput, outlink);
}

static int config_clut(AVFilterLink *inlink)
{
    int size, level, w, h;
    AVFilterContext *ctx = inlink->dst;
    LUT3DContext *lut3d = ctx->priv;
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);

    lut3d->clut_is16bit = 0;
    switch (inlink->format) {
    case AV_PIX_FMT_RGB48:
    case AV_PIX_FMT_BGR48:
    case AV_PIX_FMT_RGBA64:
    case AV_PIX_FMT_BGRA64:
        lut3d->clut_is16bit = 1;
    }

    lut3d->clut_step = av_get_padded_bits_per_pixel(desc) >> 3;
    ff_fill_rgba_map(lut3d->clut_rgba_map, inlink->format);

    if (inlink->w > inlink->h)
        av_log(ctx, AV_LOG_INFO, "Padding on the right (%dpx) of the "
               "Hald CLUT will be ignored\n", inlink->w - inlink->h);
    else if (inlink->w < inlink->h)
        av_log(ctx, AV_LOG_INFO, "Padding at the bottom (%dpx) of the "
               "Hald CLUT will be ignored\n", inlink->h - inlink->w);
    lut3d->clut_width = w = h = FFMIN(inlink->w, inlink->h);

    for (level = 1; level*level*level < w; level++);
    size = level*level*level;
    if (size != w) {
        av_log(ctx, AV_LOG_WARNING, "The Hald CLUT width does not match the level\n");
        return AVERROR_INVALIDDATA;
    }
    av_assert0(w == h && w == size);
    level *= level;
    if (level > MAX_LEVEL) {
        const int max_clut_level = sqrt(MAX_LEVEL);
        const int max_clut_size  = max_clut_level*max_clut_level*max_clut_level;
        av_log(ctx, AV_LOG_ERROR, "Too large Hald CLUT "
               "(maximum level is %d, or %dx%d CLUT)\n",
               max_clut_level, max_clut_size, max_clut_size);
        return AVERROR(EINVAL);
    }
    lut3d->lutsize = level;

    return 0;
}

static AVFrame *update_apply_clut(AVFilterContext *ctx, AVFrame *main,
                                  const AVFrame *second)
{
    AVFilterLink *inlink = ctx->inputs[0];
    update_clut(ctx->priv, second);
    return apply_lut(inlink, main);
}

static av_cold int haldclut_init(AVFilterContext *ctx)
{
    LUT3DContext *lut3d = ctx->priv;
    lut3d->dinput.process = update_apply_clut;
    return 0;
}

static av_cold void haldclut_uninit(AVFilterContext *ctx)
{
    LUT3DContext *lut3d = ctx->priv;
    ff_dualinput_uninit(&lut3d->dinput);
}

static const AVOption haldclut_options[] = {
	{ "shortest",   "force termination when the shortest input terminates", OFFSET(dinput.shortest),   AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, FLAGS },
    { "repeatlast", "continue applying the last clut after eos",            OFFSET(dinput.repeatlast), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, FLAGS },
	COMMON_OPTIONS
};

AVFILTER_DEFINE_CLASS(haldclut);

static const AVFilterPad haldclut_inputs[] = {
    {
		.name         = "main",
        .type         = AVMEDIA_TYPE_VIDEO,
        .filter_frame = filter_frame_hald,
        .config_props = config_input,
	},{
		.name         = "clut",
        .type         = AVMEDIA_TYPE_VIDEO,
        .filter_frame = filter_frame_hald,
        .config_props = config_clut,
	},
    { NULL }
};

static const AVFilterPad haldclut_outputs[] = {
    {
		.name          = "default",
        .type          = AVMEDIA_TYPE_VIDEO,
        .request_frame = request_frame,
        .config_props  = config_output,
	},
    { NULL }
};

AVFilter ff_vf_haldclut = {
	.name          = "haldclut",
    .description   = NULL_IF_CONFIG_SMALL("Adjust colors using a Hald CLUT."),
    .priv_size     = sizeof(LUT3DContext),
    .init          = haldclut_init,
    .uninit        = haldclut_uninit,
    .query_formats = query_formats,
    .inputs        = haldclut_inputs,
    .outputs       = haldclut_outputs,
    .priv_class    = &haldclut_class,
    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL | AVFILTER_FLAG_SLICE_THREADS,
};
#endif
