text: /*
   * Copyright (c) 2020 Paul B Mahol
   *
   * 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/avstring.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"
  
  typedef struct ChromaNRContext {
      const AVClass *class;
  
      float threshold;
      float threshold_y;
      float threshold_u;
      float threshold_v;
      int thres;
      int thres_y;
      int thres_u;
      int thres_v;
      int sizew;
      int sizeh;
      int stepw;
      int steph;
      int depth;
      int chroma_w;
      int chroma_h;
      int nb_planes;
      int linesize[4];
      int planeheight[4];
      int planewidth[4];
  
      AVFrame *out;
      int (*filter_slice)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
  } ChromaNRContext;
  
  static int query_formats(AVFilterContext *ctx)
  {
      static const enum AVPixelFormat pix_fmts[] = {
          AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV444P,
          AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA444P,
          AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ411P,
          AV_PIX_FMT_YUV420P9,   AV_PIX_FMT_YUV422P9,   AV_PIX_FMT_YUV444P9,
          AV_PIX_FMT_YUV420P10,  AV_PIX_FMT_YUV422P10,  AV_PIX_FMT_YUV440P10, AV_PIX_FMT_YUV444P10,
          AV_PIX_FMT_YUV444P12,  AV_PIX_FMT_YUV422P12,  AV_PIX_FMT_YUV440P12, AV_PIX_FMT_YUV420P12,
          AV_PIX_FMT_YUV444P14,  AV_PIX_FMT_YUV422P14,  AV_PIX_FMT_YUV420P14,
          AV_PIX_FMT_YUV420P16,  AV_PIX_FMT_YUV422P16,  AV_PIX_FMT_YUV444P16,
          AV_PIX_FMT_YUVA420P9,  AV_PIX_FMT_YUVA422P9,  AV_PIX_FMT_YUVA444P9,
          AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA444P10,
          AV_PIX_FMT_YUVA422P12, AV_PIX_FMT_YUVA444P12,
          AV_PIX_FMT_YUVA420P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA444P16,
          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);
  }
  
  #define FILTER_FUNC(name, type)                                                        \
  static int filter_slice##name(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)   \
  {                                                                                        \
      ChromaNRContext *s = ctx->priv;                                                      \
      AVFrame *in = arg;                                                                   \
      AVFrame *out = s->out;                                                               \
      const int in_ylinesize = in->linesize[0];                                            \
      const int in_ulinesize = in->linesize[1];                                            \
      const int in_vlinesize = in->linesize[2];                                            \
      const int out_ulinesize = out->linesize[1];                                          \
      const int out_vlinesize = out->linesize[2];                                          \
      const int chroma_w = s->chroma_w;                                                    \
      const int chroma_h = s->chroma_h;                                                    \
      const int stepw = s->stepw;                                                          \
      const int steph = s->steph;                                                          \
      const int sizew = s->sizew;                                                          \
      const int sizeh = s->sizeh;                                                          \
      const int thres = s->thres;                                                          \
      const int thres_y = s->thres_y;                                                      \
      const int thres_u = s->thres_u;                                                      \
      const int thres_v = s->thres_v;                                                      \
      const int h = s->planeheight[1];                                                     \
      const int w = s->planewidth[1];                                                      \
      const int slice_start = (h * jobnr) / nb_jobs;                                       \
      const int slice_end = (h * (jobnr+1)) / nb_jobs;                                     \
      type *out_uptr = (type *)(out->data[1] + slice_start * out_ulinesize);               \
      type *out_vptr = (type *)(out->data[2] + slice_start * out_vlinesize);               \
                                                                                           \
      {                                                                                    \
          const int h = s->planeheight[0];                                                 \
          const int slice_start = (h * jobnr) / nb_jobs;                                   \
          const int slice_end = (h * (jobnr+1)) / nb_jobs;                                 \
                                                                                           \
          av_image_copy_plane(out->data[0] + slice_start * out->linesize[0],               \
                              out->linesize[0],                                            \
                              in->data[0] + slice_start * in->linesize[0],                 \
                              in->linesize[0],                                             \
                              s->linesize[0], slice_end - slice_start);                    \
                                                                                           \
          if (s->nb_planes == 4) {                                                         \
              av_image_copy_plane(out->data[3] + slice_start * out->linesize[3],           \
                                  out->linesize[3],                                        \
                                  in->data[3] + slice_start * in->linesize[3],             \
                                  in->linesize[3],                                         \
                                  s->linesize[3], slice_end - slice_start);                \
          }                                                                                \
      }                                                                                    \
                                                                                           \
      for (int y = slice_start; y < slice_end; y++) {                                      \
          const type *in_yptr = (const type *)(in->data[0] + y * chroma_h * in_ylinesize); \
          const type *in_uptr = (const type *)(in->data[1] + y * in_ulinesize);            \
          const type *in_vptr = (const type *)(in->data[2] + y * in_vlinesize);            \
                                                                                           \
          for (int x = 0; x < w; x++) {                                                    \
              const int cy = in_yptr[x * chroma_w];                                        \
              const int cu = in_uptr[x];                                                   \
              const int cv = in_vptr[x];                                                   \
              int su = cu;                                                                 \
              int sv = cv;                                                                 \
              int cn = 1;                                                                  \
                                                                                           \
              for (int yy = FFMAX(0, y - sizeh); yy < FFMIN(y + sizeh, h); yy += steph) {           \
                  const type *in_yptr = (const type *)(in->data[0] + yy * chroma_h * in_ylinesize); \
                  const type *in_uptr = (const type *)(in->data[1] + yy * in_ulinesize);            \
                  const type *in_vptr = (const type *)(in->data[2] + yy * in_vlinesize);            \
                                                                                                    \
                  for (int xx = FFMAX(0, x - sizew); xx < FFMIN(x + sizew, w); xx += stepw) {       \
                      const int Y = in_yptr[xx * chroma_w];                              \
                      const int U = in_uptr[xx];                                         \
                      const int V = in_vptr[xx];                                         \
                                                                                         \
                      if (FFABS(cu - U) + FFABS(cv - V) + FFABS(cy - Y) < thres &&       \
                          FFABS(cu - U) < thres_u && FFABS(cv - V) < thres_v &&          \
                          FFABS(cy - Y) < thres_y &&                                     \
                          xx != x && yy != y) {                                          \
                          su += U;                                                       \
                          sv += V;                                                       \
                          cn++;                                                          \
                      }                                                                  \
                  }                                                                      \
              }                                                                          \
                                                                                         \
              out_uptr[x] = su / cn;                                                     \
              out_vptr[x] = sv / cn;                                                     \
          }                                                                              \
                                                                                         \
          out_uptr += out_ulinesize / sizeof(type);                                      \
          out_vptr += out_vlinesize / sizeof(type);                                      \
      }                                                                                  \
                                                                                         \
      return 0;                                                                          \
  }
  
  FILTER_FUNC(8,  uint8_t)
  FILTER_FUNC(16, uint16_t)
  
  static int filter_frame(AVFilterLink *inlink, AVFrame *in)
  {
      AVFilterContext *ctx = inlink->dst;
      AVFilterLink *outlink = ctx->outputs[0];
      ChromaNRContext *s = ctx->priv;
      AVFrame *out;
  
      s->thres = s->threshold * (1 << (s->depth - 8));
      s->thres_y = s->threshold_y * (1 << (s->depth - 8));
      s->thres_u = s->threshold_u * (1 << (s->depth - 8));
      s->thres_v = s->threshold_v * (1 << (s->depth - 8));
  
      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);
      s->out = out;
      ctx->internal->execute(ctx, s->filter_slice, in, NULL,
                             FFMIN3(s->planeheight[1],
                                    s->planeheight[2],
                                    ff_filter_get_nb_threads(ctx)));
  
      av_frame_free(&in);
      return ff_filter_frame(outlink, out);
  }
  
  static int config_input(AVFilterLink *inlink)
  {
      AVFilterContext *ctx = inlink->dst;
      ChromaNRContext *s = ctx->priv;
      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
      int ret;
  
      s->nb_planes = desc->nb_components;
      s->depth = desc->comp[0].depth;
      s->filter_slice = s->depth <= 8 ? filter_slice8 : filter_slice16;
      s->chroma_w = 1 << desc->log2_chroma_w;
      s->chroma_h = 1 << desc->log2_chroma_h;
      s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
      s->planeheight[0] = s->planeheight[3] = inlink->h;
      s->planewidth[1] = s->planewidth[2] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
      s->planewidth[0] = s->planewidth[3] = inlink->w;
  
      if ((ret = av_image_fill_linesizes(s->linesize, inlink->format, inlink->w)) < 0)
          return ret;
  
      return 0;
  }
  
  #define OFFSET(x) offsetof(ChromaNRContext, x)
  #define VF AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_RUNTIME_PARAM
  
  static const AVOption chromanr_options[] = {
      { "thres", "set y+u+v threshold", OFFSET(threshold), AV_OPT_TYPE_FLOAT, {.dbl=30}, 1, 200, VF },
      { "sizew", "set horizontal size", OFFSET(sizew),     AV_OPT_TYPE_INT,   {.i64=5},  1, 100, VF },
      { "sizeh", "set vertical size",   OFFSET(sizeh),     AV_OPT_TYPE_INT,   {.i64=5},  1, 100, VF },
      { "stepw", "set horizontal step", OFFSET(stepw),     AV_OPT_TYPE_INT,   {.i64=1},  1,  50, VF },
      { "steph", "set vertical step",   OFFSET(steph),     AV_OPT_TYPE_INT,   {.i64=1},  1,  50, VF },
      { "threy", "set y threshold",   OFFSET(threshold_y), AV_OPT_TYPE_FLOAT, {.dbl=200},1, 200, VF },
      { "threu", "set u threshold",   OFFSET(threshold_u), AV_OPT_TYPE_FLOAT, {.dbl=200},1, 200, VF },
      { "threv", "set v threshold",   OFFSET(threshold_v), AV_OPT_TYPE_FLOAT, {.dbl=200},1, 200, VF },
      { NULL }
  };
  
  static const AVFilterPad inputs[] = {
      {
          .name         = "default",
          .type         = AVMEDIA_TYPE_VIDEO,
          .filter_frame = filter_frame,
          .config_props = config_input,
      },
      { NULL }
  };
  
  static const AVFilterPad outputs[] = {
      {
          .name = "default",
          .type = AVMEDIA_TYPE_VIDEO,
      },
      { NULL }
  };
  
  AVFILTER_DEFINE_CLASS(chromanr);
  
  AVFilter ff_vf_chromanr = {
      .name          = "chromanr",
      .description   = NULL_IF_CONFIG_SMALL("Reduce chrominance noise."),
      .priv_size     = sizeof(ChromaNRContext),
      .priv_class    = &chromanr_class,
      .query_formats = query_formats,
      .outputs       = outputs,
      .inputs        = inputs,
      .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
      .process_command = ff_filter_process_command,
  };
  