text: /*
   * 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
   */
  
  #include "libavutil/opt.h"
  #include "libavutil/bprint.h"
  #include "libavutil/eval.h"
  #include "libavutil/file.h"
  #include "libavutil/intreadwrite.h"
  #include "libavutil/avassert.h"
  #include "libavutil/pixdesc.h"
  #include "avfilter.h"
  #include "drawutils.h"
  #include "formats.h"
  #include "internal.h"
  #include "video.h"
  
  #define R 0
  #define G 1
  #define B 2
  #define A 3
  
  struct keypoint {
      double x, y;
      struct keypoint *next;
  };
  
  #define NB_COMP 3
  
  enum preset {
      PRESET_NONE,
      PRESET_COLOR_NEGATIVE,
      PRESET_CROSS_PROCESS,
      PRESET_DARKER,
      PRESET_INCREASE_CONTRAST,
      PRESET_LIGHTER,
      PRESET_LINEAR_CONTRAST,
      PRESET_MEDIUM_CONTRAST,
      PRESET_NEGATIVE,
      PRESET_STRONG_CONTRAST,
      PRESET_VINTAGE,
      NB_PRESETS,
  };
  
  typedef struct CurvesContext {
      const AVClass *class;
      int preset;
      char *comp_points_str[NB_COMP + 1];
      char *comp_points_str_all;
      uint16_t *graph[NB_COMP + 1];
      int lut_size;
      char *psfile;
      uint8_t rgba_map[4];
      int step;
      char *plot_filename;
      int saved_plot;
      int is_16bit;
      int depth;
      int parsed_psfile;
  
      int (*filter_slice)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
  } CurvesContext;
  
  typedef struct ThreadData {
      AVFrame *in, *out;
  } ThreadData;
  
  #define OFFSET(x) offsetof(CurvesContext, x)
  #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
  static const AVOption curves_options[] = {
      { "preset", "select a color curves preset", OFFSET(preset), AV_OPT_TYPE_INT, {.i64=PRESET_NONE}, PRESET_NONE, NB_PRESETS-1, FLAGS, "preset_name" },
          { "none",               NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_NONE},                 0, 0, FLAGS, "preset_name" },
          { "color_negative",     NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_COLOR_NEGATIVE},       0, 0, FLAGS, "preset_name" },
          { "cross_process",      NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_CROSS_PROCESS},        0, 0, FLAGS, "preset_name" },
          { "darker",             NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_DARKER},               0, 0, FLAGS, "preset_name" },
          { "increase_contrast",  NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_INCREASE_CONTRAST},    0, 0, FLAGS, "preset_name" },
          { "lighter",            NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_LIGHTER},              0, 0, FLAGS, "preset_name" },
          { "linear_contrast",    NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_LINEAR_CONTRAST},      0, 0, FLAGS, "preset_name" },
          { "medium_contrast",    NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_MEDIUM_CONTRAST},      0, 0, FLAGS, "preset_name" },
          { "negative",           NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_NEGATIVE},             0, 0, FLAGS, "preset_name" },
          { "strong_contrast",    NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_STRONG_CONTRAST},      0, 0, FLAGS, "preset_name" },
          { "vintage",            NULL, 0, AV_OPT_TYPE_CONST, {.i64=PRESET_VINTAGE},              0, 0, FLAGS, "preset_name" },
      { "master","set master points coordinates",OFFSET(comp_points_str[NB_COMP]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
      { "m",     "set master points coordinates",OFFSET(comp_points_str[NB_COMP]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
      { "red",   "set red points coordinates",   OFFSET(comp_points_str[0]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
      { "r",     "set red points coordinates",   OFFSET(comp_points_str[0]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
      { "green", "set green points coordinates", OFFSET(comp_points_str[1]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
      { "g",     "set green points coordinates", OFFSET(comp_points_str[1]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
      { "blue",  "set blue points coordinates",  OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
      { "b",     "set blue points coordinates",  OFFSET(comp_points_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
      { "all",   "set points coordinates for all components", OFFSET(comp_points_str_all), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
      { "psfile", "set Photoshop curves file name", OFFSET(psfile), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
      { "plot", "save Gnuplot script of the curves in specified file", OFFSET(plot_filename), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
      { NULL }
  };
  
  AVFILTER_DEFINE_CLASS(curves);
  
  static const struct {
      const char *r;
      const char *g;
      const char *b;
      const char *master;
  } curves_presets[] = {
      [PRESET_COLOR_NEGATIVE] = {
          "0.129/1 0.466/0.498 0.725/0",
          "0.109/1 0.301/0.498 0.517/0",
          "0.098/1 0.235/0.498 0.423/0",
      },
      [PRESET_CROSS_PROCESS] = {
          "0/0 0.25/0.156 0.501/0.501 0.686/0.745 1/1",
          "0/0 0.25/0.188 0.38/0.501 0.745/0.815 1/0.815",
          "0/0 0.231/0.094 0.709/0.874 1/1",
      },
      [PRESET_DARKER]             = { .master = "0/0 0.5/0.4 1/1" },
      [PRESET_INCREASE_CONTRAST]  = { .master = "0/0 0.149/0.066 0.831/0.905 0.905/0.98 1/1" },
      [PRESET_LIGHTER]            = { .master = "0/0 0.4/0.5 1/1" },
      [PRESET_LINEAR_CONTRAST]    = { .master = "0/0 0.305/0.286 0.694/0.713 1/1" },
      [PRESET_MEDIUM_CONTRAST]    = { .master = "0/0 0.286/0.219 0.639/0.643 1/1" },
      [PRESET_NEGATIVE]           = { .master = "0/1 1/0" },
      [PRESET_STRONG_CONTRAST]    = { .master = "0/0 0.301/0.196 0.592/0.6 0.686/0.737 1/1" },
      [PRESET_VINTAGE] = {
          "0/0.11 0.42/0.51 1/0.95",
          "0/0 0.50/0.48 1/1",
          "0/0.22 0.49/0.44 1/0.8",
      }
  };
  
  static struct keypoint *make_point(double x, double y, struct keypoint *next)
  {
      struct keypoint *point = av_mallocz(sizeof(*point));
  
      if (!point)
          return NULL;
      point->x = x;
      point->y = y;
      point->next = next;
      return point;
  }
  
  static int parse_points_str(AVFilterContext *ctx, struct keypoint **points, const char *s,
                              int lut_size)
  {
      char *p = (char *)s; // strtod won't alter the string
      struct keypoint *last = NULL;
      const int scale = lut_size - 1;
  
      /* construct a linked list based on the key points string */
      while (p && *p) {
          struct keypoint *point = make_point(0, 0, NULL);
          if (!point)
              return AVERROR(ENOMEM);
          point->x = av_strtod(p, &p); if (p && *p) p++;
          point->y = av_strtod(p, &p); if (p && *p) p++;
          if (point->x < 0 || point->x > 1 || point->y < 0 || point->y > 1) {
              av_log(ctx, AV_LOG_ERROR, "Invalid key point coordinates (%f;%f), "
                     "x and y must be in the [0;1] range.\n", point->x, point->y);
              return AVERROR(EINVAL);
          }
          if (!*points)
              *points = point;
          if (last) {
              if ((int)(last->x * scale) >= (int)(point->x * scale)) {
                  av_log(ctx, AV_LOG_ERROR, "Key point coordinates (%f;%f) "
                         "and (%f;%f) are too close from each other or not "
                         "strictly increasing on the x-axis\n",
                         last->x, last->y, point->x, point->y);
                  return AVERROR(EINVAL);
              }
              last->next = point;
          }
          last = point;
      }
  
      if (*points && !(*points)->next) {
          av_log(ctx, AV_LOG_WARNING, "Only one point (at (%f;%f)) is defined, "
                 "this is unlikely to behave as you expect. You probably want"
                 "at least 2 points.",
                 (*points)->x, (*points)->y);
      }
  
      return 0;
  }
  
  static int get_nb_points(const struct keypoint *d)
  {
      int n = 0;
      while (d) {
          n++;
          d = d->next;
      }
      return n;
  }
  
  /**
   * Natural cubic spline interpolation
   * Finding curves using Cubic Splines notes by Steven Rauch and John Stockie.
   * @see http://people.math.sfu.ca/~stockie/teaching/macm316/notes/splines.pdf
   */
  
  #define CLIP(v) (nbits == 8 ? av_clip_uint8(v) : av_clip_uintp2_c(v, nbits))
  
  static inline int interpolate(void *log_ctx, uint16_t *y,
                                const struct keypoint *points, int nbits)
  {
      int i, ret = 0;
      const struct keypoint *point = points;
      double xprev = 0;
      const int lut_size = 1<<nbits;
      const int scale = lut_size - 1;
  
      double (*matrix)[3];
      double *h, *r;
      const int n = get_nb_points(points); // number of splines
  
      if (n == 0) {
          for (i = 0; i < lut_size; i++)
              y[i] = i;
          return 0;
      }
  
      if (n == 1) {
          for (i = 0; i < lut_size; i++)
              y[i] = CLIP(point->y * scale);
          return 0;
      }
  
      matrix = av_calloc(n, sizeof(*matrix));
      h = av_malloc((n - 1) * sizeof(*h));
      r = av_calloc(n, sizeof(*r));
  
      if (!matrix || !h || !r) {
          ret = AVERROR(ENOMEM);
          goto end;
      }
  
      /* h(i) = x(i+1) - x(i) */
      i = -1;
      for (point = points; point; point = point->next) {
          if (i != -1)
              h[i] = point->x - xprev;
          xprev = point->x;
          i++;
      }
  
      /* right-side of the polynomials, will be modified to contains the solution */
      point = points;
      for (i = 1; i < n - 1; i++) {
          const double yp = point->y;
          const double yc = point->next->y;
          const double yn = point->next->next->y;
          r[i] = 6 * ((yn-yc)/h[i] - (yc-yp)/h[i-1]);
          point = point->next;
      }
  
  #define BD 0 /* sub  diagonal (below main) */
  #define MD 1 /* main diagonal (center) */
  #define AD 2 /* sup  diagonal (above main) */
  
      /* left side of the polynomials into a tridiagonal matrix. */
      matrix[0][MD] = matrix[n - 1][MD] = 1;
      for (i = 1; i < n - 1; i++) {
          matrix[i][BD] = h[i-1];
          matrix[i][MD] = 2 * (h[i-1] + h[i]);
          matrix[i][AD] = h[i];
      }
  
      /* tridiagonal solving of the linear system */
      for (i = 1; i < n; i++) {
          const double den = matrix[i][MD] - matrix[i][BD] * matrix[i-1][AD];
          const double k = den ? 1./den : 1.;
          matrix[i][AD] *= k;
          r[i] = (r[i] - matrix[i][BD] * r[i - 1]) * k;
      }
      for (i = n - 2; i >= 0; i--)
          r[i] = r[i] - matrix[i][AD] * r[i + 1];
  
      point = points;
  
      /* left padding */
      for (i = 0; i < (int)(point->x * scale); i++)
          y[i] = CLIP(point->y * scale);
  
      /* compute the graph with x=[x0..xN] */
      i = 0;
      av_assert0(point->next); // always at least 2 key points
      while (point->next) {
          const double yc = point->y;
          const double yn = point->next->y;
  
          const double a = yc;
          const double b = (yn-yc)/h[i] - h[i]*r[i]/2. - h[i]*(r[i+1]-r[i])/6.;
          const double c = r[i] / 2.;
          const double d = (r[i+1] - r[i]) / (6.*h[i]);
  
          int x;
          const int x_start = point->x       * scale;
          const int x_end   = point->next->x * scale;
  
          av_assert0(x_start >= 0 && x_start < lut_size &&
                     x_end   >= 0 && x_end   < lut_size);
  
          for (x = x_start; x <= x_end; x++) {
              const double xx = (x - x_start) * 1./scale;
              const double yy = a + b*xx + c*xx*xx + d*xx*xx*xx;
              y[x] = CLIP(yy * scale);
              av_log(log_ctx, AV_LOG_DEBUG, "f(%f)=%f -> y[%d]=%d\n", xx, yy, x, y[x]);
          }
  
          point = point->next;
          i++;
      }
  
      /* right padding */
      for (i = (int)(point->x * scale); i < lut_size; i++)
          y[i] = CLIP(point->y * scale);
  
  end:
      av_free(matrix);
      av_free(h);
      av_free(r);
      return ret;
  }
  
  #define DECLARE_INTERPOLATE_FUNC(nbits)                                     \
  static int interpolate##nbits(void *log_ctx, uint16_t *y,                   \
                                const struct keypoint *points)                \
  {                                                                           \
      return interpolate(log_ctx, y, points, nbits);                          \
  }
  
  DECLARE_INTERPOLATE_FUNC(8)
  DECLARE_INTERPOLATE_FUNC(9)
  DECLARE_INTERPOLATE_FUNC(10)
  DECLARE_INTERPOLATE_FUNC(12)
  DECLARE_INTERPOLATE_FUNC(14)
  DECLARE_INTERPOLATE_FUNC(16)
  
  static int parse_psfile(AVFilterContext *ctx, const char *fname)
  {
      CurvesContext *curves = ctx->priv;
      uint8_t *buf;
      size_t size;
      int i, ret, av_unused(version), nb_curves;
      AVBPrint ptstr;
      static const int comp_ids[] = {3, 0, 1, 2};
  
      av_bprint_init(&ptstr, 0, AV_BPRINT_SIZE_AUTOMATIC);
  
      ret = av_file_map(fname, &buf, &size, 0, NULL);
      if (ret < 0)
          return ret;
  
  #define READ16(dst) do {                \
      if (size < 2) {                     \
          ret = AVERROR_INVALIDDATA;      \
          goto end;                       \
      }                                   \
      dst = AV_RB16(buf);                 \
      buf  += 2;                          \
      size -= 2;                          \
  } while (0)
  
      READ16(version);
      READ16(nb_curves);
      for (i = 0; i < FFMIN(nb_curves, FF_ARRAY_ELEMS(comp_ids)); i++) {
          int nb_points, n;
          av_bprint_clear(&ptstr);
          READ16(nb_points);
          for (n = 0; n < nb_points; n++) {
              int y, x;
              READ16(y);
              READ16(x);
              av_bprintf(&ptstr, "%f/%f ", x / 255., y / 255.);
          }
          if (*ptstr.str) {
              char **pts = &curves->comp_points_str[comp_ids[i]];
              if (!*pts) {
                  *pts = av_strdup(ptstr.str);
                  av_log(ctx, AV_LOG_DEBUG, "curves %d (intid=%d) [%d points]: [%s]\n",
                         i, comp_ids[i], nb_points, *pts);
                  if (!*pts) {
                      ret = AVERROR(ENOMEM);
                      goto end;
                  }
              }
          }
      }
  end:
      av_bprint_finalize(&ptstr, NULL);
      av_file_unmap(buf, size);
      return ret;
  }
  
  static int dump_curves(const char *fname, uint16_t *graph[NB_COMP + 1],
                         struct keypoint *comp_points[NB_COMP + 1],
                         int lut_size)
  {
      int i;
      AVBPrint buf;
      const double scale = 1. / (lut_size - 1);
      static const char * const colors[] = { "red", "green", "blue", "#404040", };
      FILE *f = av_fopen_utf8(fname, "w");
  
      av_assert0(FF_ARRAY_ELEMS(colors) == NB_COMP + 1);
  
      if (!f) {
          int ret = AVERROR(errno);
          av_log(NULL, AV_LOG_ERROR, "Cannot open file '%s' for writing: %s\n",
                 fname, av_err2str(ret));
          return ret;
      }
  
      av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
  
      av_bprintf(&buf, "set xtics 0.1\n");
      av_bprintf(&buf, "set ytics 0.1\n");
      av_bprintf(&buf, "set size square\n");
      av_bprintf(&buf, "set grid\n");
  
      for (i = 0; i < FF_ARRAY_ELEMS(colors); i++) {
          av_bprintf(&buf, "%s'-' using 1:2 with lines lc '%s' title ''",
                     i ? ", " : "plot ", colors[i]);
          if (comp_points[i])
              av_bprintf(&buf, ", '-' using 1:2 with points pointtype 3 lc '%s' title ''",
                      colors[i]);
      }
      av_bprintf(&buf, "\n");
  
      for (i = 0; i < FF_ARRAY_ELEMS(colors); i++) {
          int x;
  
          /* plot generated values */
          for (x = 0; x < lut_size; x++)
              av_bprintf(&buf, "%f %f\n", x * scale, graph[i][x] * scale);
          av_bprintf(&buf, "e\n");
  
          /* plot user knots */
          if (comp_points[i]) {
              const struct keypoint *point = comp_points[i];
  
              while (point) {
                  av_bprintf(&buf, "%f %f\n", point->x, point->y);
                  point = point->next;
              }
              av_bprintf(&buf, "e\n");
          }
      }
  
      fwrite(buf.str, 1, buf.len, f);
      fclose(f);
      av_bprint_finalize(&buf, NULL);
      return 0;
  }
  
  static av_cold int curves_init(AVFilterContext *ctx)
  {
      int i, ret;
      CurvesContext *curves = ctx->priv;
      char **pts = curves->comp_points_str;
      const char *allp = curves->comp_points_str_all;
  
      //if (!allp && curves->preset != PRESET_NONE && curves_presets[curves->preset].all)
      //    allp = curves_presets[curves->preset].all;
  
      if (allp) {
          for (i = 0; i < NB_COMP; i++) {
              if (!pts[i])
                  pts[i] = av_strdup(allp);
              if (!pts[i])
                  return AVERROR(ENOMEM);
          }
      }
  
      if (curves->psfile && !curves->parsed_psfile) {
          ret = parse_psfile(ctx, curves->psfile);
          if (ret < 0)
              return ret;
          curves->parsed_psfile = 1;
      }
  
      if (curves->preset != PRESET_NONE) {
  #define SET_COMP_IF_NOT_SET(n, name) do {                           \
      if (!pts[n] && curves_presets[curves->preset].name) {           \
          pts[n] = av_strdup(curves_presets[curves->preset].name);    \
          if (!pts[n])                                                \
              return AVERROR(ENOMEM);                                 \
      }                                                               \
  } while (0)
          SET_COMP_IF_NOT_SET(0, r);
          SET_COMP_IF_NOT_SET(1, g);
          SET_COMP_IF_NOT_SET(2, b);
          SET_COMP_IF_NOT_SET(3, master);
          curves->preset = PRESET_NONE;
      }
  
      return 0;
  }
  
  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_GBRP,   AV_PIX_FMT_GBRAP,
          AV_PIX_FMT_GBRP9,
          AV_PIX_FMT_GBRP10, AV_PIX_FMT_GBRAP10,
          AV_PIX_FMT_GBRP12, AV_PIX_FMT_GBRAP12,
          AV_PIX_FMT_GBRP14,
          AV_PIX_FMT_GBRP16, AV_PIX_FMT_GBRAP16,
          AV_PIX_FMT_NONE
      };
      AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
      if (!fmts_list)
          return AVERROR(ENOMEM);
      return ff_set_common_formats(ctx, fmts_list);
  }
  
  static int filter_slice_packed(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
  {
      int x, y;
      const CurvesContext *curves = ctx->priv;
      const ThreadData *td = arg;
      const AVFrame *in  = td->in;
      const AVFrame *out = td->out;
      const int direct = out == in;
      const int step = curves->step;
      const uint8_t r = curves->rgba_map[R];
      const uint8_t g = curves->rgba_map[G];
      const uint8_t b = curves->rgba_map[B];
      const uint8_t a = curves->rgba_map[A];
      const int slice_start = (in->height *  jobnr   ) / nb_jobs;
      const int slice_end   = (in->height * (jobnr+1)) / nb_jobs;
  
      if (curves->is_16bit) {
          for (y = slice_start; y < slice_end; y++) {
              uint16_t       *dstp = (      uint16_t *)(out->data[0] + y * out->linesize[0]);
              const uint16_t *srcp = (const uint16_t *)(in ->data[0] + y *  in->linesize[0]);
  
              for (x = 0; x < in->width * step; x += step) {
                  dstp[x + r] = curves->graph[R][srcp[x + r]];
                  dstp[x + g] = curves->graph[G][srcp[x + g]];
                  dstp[x + b] = curves->graph[B][srcp[x + b]];
                  if (!direct && step == 4)
                      dstp[x + a] = srcp[x + a];
              }
          }
      } else {
          uint8_t       *dst = out->data[0] + slice_start * out->linesize[0];
          const uint8_t *src =  in->data[0] + slice_start *  in->linesize[0];
  
          for (y = slice_start; y < slice_end; y++) {
              for (x = 0; x < in->width * step; x += step) {
                  dst[x + r] = curves->graph[R][src[x + r]];
                  dst[x + g] = curves->graph[G][src[x + g]];
                  dst[x + b] = curves->graph[B][src[x + b]];
                  if (!direct && step == 4)
                      dst[x + a] = src[x + a];
              }
              dst += out->linesize[0];
              src += in ->linesize[0];
          }
      }
      return 0;
  }
  
  static int filter_slice_planar(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
  {
      int x, y;
      const CurvesContext *curves = ctx->priv;
      const ThreadData *td = arg;
      const AVFrame *in  = td->in;
      const AVFrame *out = td->out;
      const int direct = out == in;
      const int step = curves->step;
      const uint8_t r = curves->rgba_map[R];
      const uint8_t g = curves->rgba_map[G];
      const uint8_t b = curves->rgba_map[B];
      const uint8_t a = curves->rgba_map[A];
      const int slice_start = (in->height *  jobnr   ) / nb_jobs;
      const int slice_end   = (in->height * (jobnr+1)) / nb_jobs;
  
      if (curves->is_16bit) {
          for (y = slice_start; y < slice_end; y++) {
              uint16_t       *dstrp = (      uint16_t *)(out->data[r] + y * out->linesize[r]);
              uint16_t       *dstgp = (      uint16_t *)(out->data[g] + y * out->linesize[g]);
              uint16_t       *dstbp = (      uint16_t *)(out->data[b] + y * out->linesize[b]);
              uint16_t       *dstap = (      uint16_t *)(out->data[a] + y * out->linesize[a]);
              const uint16_t *srcrp = (const uint16_t *)(in ->data[r] + y *  in->linesize[r]);
              const uint16_t *srcgp = (const uint16_t *)(in ->data[g] + y *  in->linesize[g]);
              const uint16_t *srcbp = (const uint16_t *)(in ->data[b] + y *  in->linesize[b]);
              const uint16_t *srcap = (const uint16_t *)(in ->data[a] + y *  in->linesize[a]);
  
              for (x = 0; x < in->width; x++) {
                  dstrp[x] = curves->graph[R][srcrp[x]];
                  dstgp[x] = curves->graph[G][srcgp[x]];
                  dstbp[x] = curves->graph[B][srcbp[x]];
                  if (!direct && step == 4)
                      dstap[x] = srcap[x];
              }
          }
      } else {
          uint8_t       *dstr = out->data[r] + slice_start * out->linesize[r];
          uint8_t       *dstg = out->data[g] + slice_start * out->linesize[g];
          uint8_t       *dstb = out->data[b] + slice_start * out->linesize[b];
          uint8_t       *dsta = out->data[a] + slice_start * out->linesize[a];
          const uint8_t *srcr =  in->data[r] + slice_start *  in->linesize[r];
          const uint8_t *srcg =  in->data[g] + slice_start *  in->linesize[g];
          const uint8_t *srcb =  in->data[b] + slice_start *  in->linesize[b];
          const uint8_t *srca =  in->data[a] + slice_start *  in->linesize[a];
  
          for (y = slice_start; y < slice_end; y++) {
              for (x = 0; x < in->width; x++) {
                  dstr[x] = curves->graph[R][srcr[x]];
                  dstg[x] = curves->graph[G][srcg[x]];
                  dstb[x] = curves->graph[B][srcb[x]];
                  if (!direct && step == 4)
                      dsta[x] = srca[x];
              }
              dstr += out->linesize[r];
              dstg += out->linesize[g];
              dstb += out->linesize[b];
              dsta += out->linesize[a];
              srcr += in ->linesize[r];
              srcg += in ->linesize[g];
              srcb += in ->linesize[b];
              srca += in ->linesize[a];
          }
      }
      return 0;
  }
  
  static int config_input(AVFilterLink *inlink)
  {
      int i, j, ret;
      AVFilterContext *ctx = inlink->dst;
      CurvesContext *curves = ctx->priv;
      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
      char **pts = curves->comp_points_str;
      struct keypoint *comp_points[NB_COMP + 1] = {0};
  
      ff_fill_rgba_map(curves->rgba_map, inlink->format);
      curves->is_16bit = desc->comp[0].depth > 8;
      curves->depth = desc->comp[0].depth;
      curves->lut_size = 1 << curves->depth;
      curves->step = av_get_padded_bits_per_pixel(desc) >> (3 + curves->is_16bit);
      curves->filter_slice = desc->flags & AV_PIX_FMT_FLAG_PLANAR ? filter_slice_planar : filter_slice_packed;
  
      for (i = 0; i < NB_COMP + 1; i++) {
          if (!curves->graph[i])
              curves->graph[i] = av_mallocz_array(curves->lut_size, sizeof(*curves->graph[0]));
          if (!curves->graph[i])
              return AVERROR(ENOMEM);
          ret = parse_points_str(ctx, comp_points + i, curves->comp_points_str[i], curves->lut_size);
          if (ret < 0)
              return ret;
          switch (curves->depth) {
          case  8: ret = interpolate8 (ctx, curves->graph[i], comp_points[i]); break;
          case  9: ret = interpolate9 (ctx, curves->graph[i], comp_points[i]); break;
          case 10: ret = interpolate10(ctx, curves->graph[i], comp_points[i]); break;
          case 12: ret = interpolate12(ctx, curves->graph[i], comp_points[i]); break;
          case 14: ret = interpolate14(ctx, curves->graph[i], comp_points[i]); break;
          case 16: ret = interpolate16(ctx, curves->graph[i], comp_points[i]); break;
          }
          if (ret < 0)
              return ret;
      }
  
      if (pts[NB_COMP]) {
          for (i = 0; i < NB_COMP; i++)
              for (j = 0; j < curves->lut_size; j++)
                  curves->graph[i][j] = curves->graph[NB_COMP][curves->graph[i][j]];
      }
  
      if (av_log_get_level() >= AV_LOG_VERBOSE) {
          for (i = 0; i < NB_COMP; i++) {
              const struct keypoint *point = comp_points[i];
              av_log(ctx, AV_LOG_VERBOSE, "#%d points:", i);
              while (point) {
                  av_log(ctx, AV_LOG_VERBOSE, " (%f;%f)", point->x, point->y);
                  point = point->next;
              }
          }
      }
  
      if (curves->plot_filename && !curves->saved_plot) {
          dump_curves(curves->plot_filename, curves->graph, comp_points, curves->lut_size);
          curves->saved_plot = 1;
      }
  
      for (i = 0; i < NB_COMP + 1; i++) {
          struct keypoint *point = comp_points[i];
          while (point) {
              struct keypoint *next = point->next;
              av_free(point);
              point = next;
          }
      }
  
      return 0;
  }
  
  static int filter_frame(AVFilterLink *inlink, AVFrame *in)
  {
      AVFilterContext *ctx = inlink->dst;
      CurvesContext *curves = ctx->priv;
      AVFilterLink *outlink = ctx->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 AVERROR(ENOMEM);
          }
          av_frame_copy_props(out, in);
      }
  
      td.in  = in;
      td.out = out;
      ctx->internal->execute(ctx, curves->filter_slice, &td, NULL, FFMIN(outlink->h, ff_filter_get_nb_threads(ctx)));
  
      if (out != in)
          av_frame_free(&in);
  
      return ff_filter_frame(outlink, out);
  }
  
  static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
                             char *res, int res_len, int flags)
  {
      CurvesContext *curves = ctx->priv;
      int ret;
  
      if (!strcmp(cmd, "plot")) {
          curves->saved_plot = 0;
      } else if (!strcmp(cmd, "all") || !strcmp(cmd, "preset") || !strcmp(cmd, "psfile")) {
          if (!strcmp(cmd, "psfile"))
              curves->parsed_psfile = 0;
          av_freep(&curves->comp_points_str_all);
          av_freep(&curves->comp_points_str[0]);
          av_freep(&curves->comp_points_str[1]);
          av_freep(&curves->comp_points_str[2]);
          av_freep(&curves->comp_points_str[NB_COMP]);
      } else if (!strcmp(cmd, "red") || !strcmp(cmd, "r")) {
          av_freep(&curves->comp_points_str[0]);
      } else if (!strcmp(cmd, "green") || !strcmp(cmd, "g")) {
          av_freep(&curves->comp_points_str[1]);
      } else if (!strcmp(cmd, "blue") || !strcmp(cmd, "b")) {
          av_freep(&curves->comp_points_str[2]);
      } else if (!strcmp(cmd, "master") || !strcmp(cmd, "m")) {
          av_freep(&curves->comp_points_str[NB_COMP]);
      }
  
      ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
      if (ret < 0)
          return ret;
  
      ret = curves_init(ctx);
      if (ret < 0)
          return ret;
      return config_input(ctx->inputs[0]);
  }
  
  static av_cold void curves_uninit(AVFilterContext *ctx)
  {
      int i;
      CurvesContext *curves = ctx->priv;
  
      for (i = 0; i < NB_COMP + 1; i++)
          av_freep(&curves->graph[i]);
  }
  
  static const AVFilterPad curves_inputs[] = {
      {
          .name         = "default",
          .type         = AVMEDIA_TYPE_VIDEO,
          .filter_frame = filter_frame,
          .config_props = config_input,
      },
      { NULL }
  };
  
  static const AVFilterPad curves_outputs[] = {
      {
          .name = "default",
          .type = AVMEDIA_TYPE_VIDEO,
      },
      { NULL }
  };
  
  AVFilter ff_vf_curves = {
      .name          = "curves",
      .description   = NULL_IF_CONFIG_SMALL("Adjust components curves."),
      .priv_size     = sizeof(CurvesContext),
      .init          = curves_init,
      .uninit        = curves_uninit,
      .query_formats = query_formats,
      .inputs        = curves_inputs,
      .outputs       = curves_outputs,
      .priv_class    = &curves_class,
      .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
      .process_command = process_command,
  };
  