text: /*
   * Copyright (c) 2003 Michael Niedermayer
   * Copyright (c) 2012 Jeremy Tran
   *
   * 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
   * Apply a hue/saturation filter to the input video
   * Ported from MPlayer libmpcodecs/vf_hue.c.
   */
  
  #include <float.h>
  #include "libavutil/eval.h"
  #include "libavutil/imgutils.h"
  #include "libavutil/opt.h"
  #include "libavutil/pixdesc.h"
  
  #include "avfilter.h"
  #include "formats.h"
  #include "internal.h"
  #include "video.h"
  
  #define SAT_MIN_VAL -10
  #define SAT_MAX_VAL 10
  
  static const char *const var_names[] = {
      "n",   // frame count
      "pts", // presentation timestamp expressed in AV_TIME_BASE units
      "r",   // frame rate
      "t",   // timestamp expressed in seconds
      "tb",  // timebase
      NULL
  };
  
  enum var_name {
      VAR_N,
      VAR_PTS,
      VAR_R,
      VAR_T,
      VAR_TB,
      VAR_NB
  };
  
  typedef struct HueContext {
      const    AVClass *class;
      float    hue_deg; /* hue expressed in degrees */
      float    hue; /* hue expressed in radians */
      char     *hue_deg_expr;
      char     *hue_expr;
      AVExpr   *hue_deg_pexpr;
      AVExpr   *hue_pexpr;
      float    saturation;
      char     *saturation_expr;
      AVExpr   *saturation_pexpr;
      float    brightness;
      char     *brightness_expr;
      AVExpr   *brightness_pexpr;
      int      hsub;
      int      vsub;
      int is_first;
      int32_t hue_sin;
      int32_t hue_cos;
      double   var_values[VAR_NB];
      uint8_t  lut_l[256];
      uint8_t  lut_u[256][256];
      uint8_t  lut_v[256][256];
      uint16_t  lut_l16[65536];
      uint16_t  lut_u10[1024][1024];
      uint16_t  lut_v10[1024][1024];
  } HueContext;
  
  #define OFFSET(x) offsetof(HueContext, x)
  #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
  static const AVOption hue_options[] = {
      { "h", "set the hue angle degrees expression", OFFSET(hue_deg_expr), AV_OPT_TYPE_STRING,
        { .str = NULL }, .flags = FLAGS },
      { "s", "set the saturation expression", OFFSET(saturation_expr), AV_OPT_TYPE_STRING,
        { .str = "1" }, .flags = FLAGS },
      { "H", "set the hue angle radians expression", OFFSET(hue_expr), AV_OPT_TYPE_STRING,
        { .str = NULL }, .flags = FLAGS },
      { "b", "set the brightness expression", OFFSET(brightness_expr), AV_OPT_TYPE_STRING,
        { .str = "0" }, .flags = FLAGS },
      { NULL }
  };
  
  AVFILTER_DEFINE_CLASS(hue);
  
  static inline void compute_sin_and_cos(HueContext *hue)
  {
      /*
       * Scale the value to the norm of the resulting (U,V) vector, that is
       * the saturation.
       * This will be useful in the apply_lut function.
       */
      hue->hue_sin = lrint(sin(hue->hue) * (1 << 16) * hue->saturation);
      hue->hue_cos = lrint(cos(hue->hue) * (1 << 16) * hue->saturation);
  }
  
  static inline void create_luma_lut(HueContext *h)
  {
      const float b = h->brightness;
      int i;
  
      for (i = 0; i < 256; i++) {
          h->lut_l[i] = av_clip_uint8(i + b * 25.5);
      }
      for (i = 0; i < 65536; i++) {
          h->lut_l16[i] = av_clip_uintp2(i + b * 102.4, 10);
      }
  }
  
  static inline void create_chrominance_lut(HueContext *h, const int32_t c,
                                            const int32_t s)
  {
      int32_t i, j, u, v, new_u, new_v;
  
      /*
       * If we consider U and V as the components of a 2D vector then its angle
       * is the hue and the norm is the saturation
       */
      for (i = 0; i < 256; i++) {
          for (j = 0; j < 256; j++) {
              /* Normalize the components from range [16;240] to [-112;112] */
              u = i - 128;
              v = j - 128;
              /*
               * Apply the rotation of the vector : (c * u) - (s * v)
               *                                    (s * u) + (c * v)
               * De-normalize the components (without forgetting to scale 128
               * by << 16)
               * Finally scale back the result by >> 16
               */
              new_u = ((c * u) - (s * v) + (1 << 15) + (128 << 16)) >> 16;
              new_v = ((s * u) + (c * v) + (1 << 15) + (128 << 16)) >> 16;
  
              /* Prevent a potential overflow */
              h->lut_u[i][j] = av_clip_uint8(new_u);
              h->lut_v[i][j] = av_clip_uint8(new_v);
          }
      }
      for (i = 0; i < 1024; i++) {
          for (j = 0; j < 1024; j++) {
              u = i - 512;
              v = j - 512;
              /*
               * Apply the rotation of the vector : (c * u) - (s * v)
               *                                    (s * u) + (c * v)
               * De-normalize the components (without forgetting to scale 512
               * by << 16)
               * Finally scale back the result by >> 16
               */
              new_u = ((c * u) - (s * v) + (1 << 15) + (512 << 16)) >> 16;
              new_v = ((s * u) + (c * v) + (1 << 15) + (512 << 16)) >> 16;
  
              /* Prevent a potential overflow */
              h->lut_u10[i][j] = av_clip_uintp2(new_u, 10);
              h->lut_v10[i][j] = av_clip_uintp2(new_v, 10);
          }
      }
  }
  
  static int set_expr(AVExpr **pexpr_ptr, char **expr_ptr,
                      const char *expr, const char *option, void *log_ctx)
  {
      int ret;
      AVExpr *new_pexpr;
      char *new_expr;
  
      new_expr = av_strdup(expr);
      if (!new_expr)
          return AVERROR(ENOMEM);
      ret = av_expr_parse(&new_pexpr, expr, var_names,
                          NULL, NULL, NULL, NULL, 0, log_ctx);
      if (ret < 0) {
          av_log(log_ctx, AV_LOG_ERROR,
                 "Error when evaluating the expression '%s' for %s\n",
                 expr, option);
          av_free(new_expr);
          return ret;
      }
  
      if (*pexpr_ptr)
          av_expr_free(*pexpr_ptr);
      *pexpr_ptr = new_pexpr;
      av_freep(expr_ptr);
      *expr_ptr = new_expr;
  
      return 0;
  }
  
  static av_cold int init(AVFilterContext *ctx)
  {
      HueContext *hue = ctx->priv;
      int ret;
  
      if (hue->hue_expr && hue->hue_deg_expr) {
          av_log(ctx, AV_LOG_ERROR,
                 "H and h options are incompatible and cannot be specified "
                 "at the same time\n");
          return AVERROR(EINVAL);
      }
  
  #define SET_EXPR(expr, option)                                          \
      if (hue->expr##_expr) do {                                          \
          ret = set_expr(&hue->expr##_pexpr, &hue->expr##_expr,           \
                         hue->expr##_expr, option, ctx);                  \
          if (ret < 0)                                                    \
              return ret;                                                 \
      } while (0)
      SET_EXPR(brightness, "b");
      SET_EXPR(saturation, "s");
      SET_EXPR(hue_deg,    "h");
      SET_EXPR(hue,        "H");
  #undef SET_EXPR
  
      av_log(ctx, AV_LOG_VERBOSE,
             "H_expr:%s h_deg_expr:%s s_expr:%s b_expr:%s\n",
             hue->hue_expr, hue->hue_deg_expr, hue->saturation_expr, hue->brightness_expr);
      compute_sin_and_cos(hue);
      hue->is_first = 1;
  
      return 0;
  }
  
  static av_cold void uninit(AVFilterContext *ctx)
  {
      HueContext *hue = ctx->priv;
  
      av_expr_free(hue->brightness_pexpr);
      av_expr_free(hue->hue_deg_pexpr);
      av_expr_free(hue->hue_pexpr);
      av_expr_free(hue->saturation_pexpr);
  }
  
  static int query_formats(AVFilterContext *ctx)
  {
      static const enum AVPixelFormat pix_fmts[] = {
          AV_PIX_FMT_YUV444P,      AV_PIX_FMT_YUV422P,
          AV_PIX_FMT_YUV420P,      AV_PIX_FMT_YUV411P,
          AV_PIX_FMT_YUV410P,      AV_PIX_FMT_YUV440P,
          AV_PIX_FMT_YUVA444P,     AV_PIX_FMT_YUVA422P,
          AV_PIX_FMT_YUVA420P,
          AV_PIX_FMT_YUV444P10,      AV_PIX_FMT_YUV422P10,
          AV_PIX_FMT_YUV420P10,
          AV_PIX_FMT_YUV440P10,
          AV_PIX_FMT_YUVA444P10,     AV_PIX_FMT_YUVA422P10,
          AV_PIX_FMT_YUVA420P10,
          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 config_props(AVFilterLink *inlink)
  {
      HueContext *hue = inlink->dst->priv;
      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
  
      hue->hsub = desc->log2_chroma_w;
      hue->vsub = desc->log2_chroma_h;
  
      hue->var_values[VAR_N]  = 0;
      hue->var_values[VAR_TB] = av_q2d(inlink->time_base);
      hue->var_values[VAR_R]  = inlink->frame_rate.num == 0 || inlink->frame_rate.den == 0 ?
          NAN : av_q2d(inlink->frame_rate);
  
      return 0;
  }
  
  static void apply_luma_lut(HueContext *s,
                             uint8_t *ldst, const int dst_linesize,
                             uint8_t *lsrc, const int src_linesize,
                             int w, int h)
  {
      int i;
  
      while (h--) {
          for (i = 0; i < w; i++)
              ldst[i] = s->lut_l[lsrc[i]];
  
          lsrc += src_linesize;
          ldst += dst_linesize;
      }
  }
  
  static void apply_luma_lut10(HueContext *s,
                               uint16_t *ldst, const int dst_linesize,
                               uint16_t *lsrc, const int src_linesize,
                               int w, int h)
  {
      int i;
  
      while (h--) {
          for (i = 0; i < w; i++)
              ldst[i] = s->lut_l16[lsrc[i]];
  
          lsrc += src_linesize;
          ldst += dst_linesize;
      }
  }
  
  static void apply_lut(HueContext *s,
                        uint8_t *udst, uint8_t *vdst, const int dst_linesize,
                        uint8_t *usrc, uint8_t *vsrc, const int src_linesize,
                        int w, int h)
  {
      int i;
  
      while (h--) {
          for (i = 0; i < w; i++) {
              const int u = usrc[i];
              const int v = vsrc[i];
  
              udst[i] = s->lut_u[u][v];
              vdst[i] = s->lut_v[u][v];
          }
  
          usrc += src_linesize;
          vsrc += src_linesize;
          udst += dst_linesize;
          vdst += dst_linesize;
      }
  }
  
  static void apply_lut10(HueContext *s,
                        uint16_t *udst, uint16_t *vdst, const int dst_linesize,
                        uint16_t *usrc, uint16_t *vsrc, const int src_linesize,
                        int w, int h)
  {
      int i;
  
      while (h--) {
          for (i = 0; i < w; i++) {
              const int u = av_clip_uintp2(usrc[i], 10);
              const int v = av_clip_uintp2(vsrc[i], 10);
  
              udst[i] = s->lut_u10[u][v];
              vdst[i] = s->lut_v10[u][v];
          }
  
          usrc += src_linesize;
          vsrc += src_linesize;
          udst += dst_linesize;
          vdst += dst_linesize;
      }
  }
  
  #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
  #define TS2T(ts, tb) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts) * av_q2d(tb))
  
  static int filter_frame(AVFilterLink *inlink, AVFrame *inpic)
  {
      HueContext *hue = inlink->dst->priv;
      AVFilterLink *outlink = inlink->dst->outputs[0];
      AVFrame *outpic;
      const int32_t old_hue_sin = hue->hue_sin, old_hue_cos = hue->hue_cos;
      const float old_brightness = hue->brightness;
      int direct = 0;
      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
      const int bps = desc->comp[0].depth > 8 ? 2 : 1;
  
      if (av_frame_is_writable(inpic)) {
          direct = 1;
          outpic = inpic;
      } else {
          outpic = ff_get_video_buffer(outlink, outlink->w, outlink->h);
          if (!outpic) {
              av_frame_free(&inpic);
              return AVERROR(ENOMEM);
          }
          av_frame_copy_props(outpic, inpic);
      }
  
      hue->var_values[VAR_N]   = inlink->frame_count_out;
      hue->var_values[VAR_T]   = TS2T(inpic->pts, inlink->time_base);
      hue->var_values[VAR_PTS] = TS2D(inpic->pts);
  
      if (hue->saturation_expr) {
          hue->saturation = av_expr_eval(hue->saturation_pexpr, hue->var_values, NULL);
  
          if (hue->saturation < SAT_MIN_VAL || hue->saturation > SAT_MAX_VAL) {
              hue->saturation = av_clip(hue->saturation, SAT_MIN_VAL, SAT_MAX_VAL);
              av_log(inlink->dst, AV_LOG_WARNING,
                     "Saturation value not in range [%d,%d]: clipping value to %0.1f\n",
                     SAT_MIN_VAL, SAT_MAX_VAL, hue->saturation);
          }
      }
  
      if (hue->brightness_expr) {
          hue->brightness = av_expr_eval(hue->brightness_pexpr, hue->var_values, NULL);
  
          if (hue->brightness < -10 || hue->brightness > 10) {
              hue->brightness = av_clipf(hue->brightness, -10, 10);
              av_log(inlink->dst, AV_LOG_WARNING,
                     "Brightness value not in range [%d,%d]: clipping value to %0.1f\n",
                     -10, 10, hue->brightness);
          }
      }
  
      if (hue->hue_deg_expr) {
          hue->hue_deg = av_expr_eval(hue->hue_deg_pexpr, hue->var_values, NULL);
          hue->hue = hue->hue_deg * M_PI / 180;
      } else if (hue->hue_expr) {
          hue->hue = av_expr_eval(hue->hue_pexpr, hue->var_values, NULL);
          hue->hue_deg = hue->hue * 180 / M_PI;
      }
  
      av_log(inlink->dst, AV_LOG_DEBUG,
             "H:%0.1f*PI h:%0.1f s:%0.1f b:%0.f t:%0.1f n:%d\n",
             hue->hue/M_PI, hue->hue_deg, hue->saturation, hue->brightness,
             hue->var_values[VAR_T], (int)hue->var_values[VAR_N]);
  
      compute_sin_and_cos(hue);
      if (hue->is_first || (old_hue_sin != hue->hue_sin || old_hue_cos != hue->hue_cos))
          create_chrominance_lut(hue, hue->hue_cos, hue->hue_sin);
  
      if (hue->is_first || (old_brightness != hue->brightness && hue->brightness))
          create_luma_lut(hue);
  
      if (!direct) {
          if (!hue->brightness)
              av_image_copy_plane(outpic->data[0], outpic->linesize[0],
                                  inpic->data[0],   inpic->linesize[0],
                                  inlink->w * bps, inlink->h);
          if (inpic->data[3])
              av_image_copy_plane(outpic->data[3], outpic->linesize[3],
                                  inpic->data[3],   inpic->linesize[3],
                                  inlink->w * bps, inlink->h);
      }
  
      if (bps > 1) {
          apply_lut10(hue, (uint16_t*)outpic->data[1], (uint16_t*)outpic->data[2], outpic->linesize[1]/2,
                           (uint16_t*) inpic->data[1], (uint16_t*) inpic->data[2],  inpic->linesize[1]/2,
                      AV_CEIL_RSHIFT(inlink->w, hue->hsub),
                      AV_CEIL_RSHIFT(inlink->h, hue->vsub));
          if (hue->brightness)
              apply_luma_lut10(hue, (uint16_t*)outpic->data[0], outpic->linesize[0]/2,
                                    (uint16_t*) inpic->data[0],  inpic->linesize[0]/2, inlink->w, inlink->h);
      } else {
          apply_lut(hue, outpic->data[1], outpic->data[2], outpic->linesize[1],
                         inpic->data[1],   inpic->data[2],  inpic->linesize[1],
                    AV_CEIL_RSHIFT(inlink->w, hue->hsub),
                    AV_CEIL_RSHIFT(inlink->h, hue->vsub));
          if (hue->brightness)
              apply_luma_lut(hue, outpic->data[0], outpic->linesize[0],
                                  inpic->data[0],  inpic->linesize[0], inlink->w, inlink->h);
      }
  
      if (!direct)
          av_frame_free(&inpic);
  
      hue->is_first = 0;
      return ff_filter_frame(outlink, outpic);
  }
  
  static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
                             char *res, int res_len, int flags)
  {
      HueContext *hue = ctx->priv;
      int ret;
  
  #define SET_EXPR(expr, option)                                          \
      do {                                                                \
          ret = set_expr(&hue->expr##_pexpr, &hue->expr##_expr,           \
                         args, option, ctx);                              \
          if (ret < 0)                                                    \
              return ret;                                                 \
      } while (0)
  
      if (!strcmp(cmd, "h")) {
          SET_EXPR(hue_deg, "h");
          av_freep(&hue->hue_expr);
      } else if (!strcmp(cmd, "H")) {
          SET_EXPR(hue, "H");
          av_freep(&hue->hue_deg_expr);
      } else if (!strcmp(cmd, "s")) {
          SET_EXPR(saturation, "s");
      } else if (!strcmp(cmd, "b")) {
          SET_EXPR(brightness, "b");
      } else
          return AVERROR(ENOSYS);
  
      return 0;
  }
  
  static const AVFilterPad hue_inputs[] = {
      {
          .name         = "default",
          .type         = AVMEDIA_TYPE_VIDEO,
          .filter_frame = filter_frame,
          .config_props = config_props,
      },
      { NULL }
  };
  
  static const AVFilterPad hue_outputs[] = {
      {
          .name = "default",
          .type = AVMEDIA_TYPE_VIDEO,
      },
      { NULL }
  };
  
  AVFilter ff_vf_hue = {
      .name            = "hue",
      .description     = NULL_IF_CONFIG_SMALL("Adjust the hue and saturation of the input video."),
      .priv_size       = sizeof(HueContext),
      .init            = init,
      .uninit          = uninit,
      .query_formats   = query_formats,
      .process_command = process_command,
      .inputs          = hue_inputs,
      .outputs         = hue_outputs,
      .priv_class      = &hue_class,
      .flags           = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
  };
  