text: /*
   * Copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
   * Copyright (c) 2013 Clément Bœsch <ubitux@gmail.com>
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 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 General Public License for more details.
   *
   * You should have received a copy of the GNU 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.
   */
  
  /**
   * @todo try to change to int
   * @todo try lifting based implementation
   * @todo optimize optimize optimize
   * @todo hard thresholding
   * @todo use QP to decide filter strength
   * @todo wavelet normalization / least squares optimal signal vs. noise thresholds
   */
  
  #include "libavutil/imgutils.h"
  #include "libavutil/opt.h"
  #include "libavutil/pixdesc.h"
  #include "avfilter.h"
  #include "internal.h"
  
  typedef struct {
      const AVClass *class;
      double luma_strength;
      double chroma_strength;
      int depth;
      float *plane[16+1][4];
      int linesize;
      int hsub, vsub;
  } OWDenoiseContext;
  
  #define OFFSET(x) offsetof(OWDenoiseContext, x)
  #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
  static const AVOption owdenoise_options[] = {
      { "depth",           "set depth",           OFFSET(depth),           AV_OPT_TYPE_INT,    {.i64 =   8}, 8,   16, FLAGS },
      { "luma_strength",   "set luma strength",   OFFSET(luma_strength),   AV_OPT_TYPE_DOUBLE, {.dbl = 1.0}, 0, 1000, FLAGS },
      { "ls",              "set luma strength",   OFFSET(luma_strength),   AV_OPT_TYPE_DOUBLE, {.dbl = 1.0}, 0, 1000, FLAGS },
      { "chroma_strength", "set chroma strength", OFFSET(chroma_strength), AV_OPT_TYPE_DOUBLE, {.dbl = 1.0}, 0, 1000, FLAGS },
      { "cs",              "set chroma strength", OFFSET(chroma_strength), AV_OPT_TYPE_DOUBLE, {.dbl = 1.0}, 0, 1000, FLAGS },
      { NULL }
  };
  
  AVFILTER_DEFINE_CLASS(owdenoise);
  
  DECLARE_ALIGNED(8, static const uint8_t, dither)[8][8] = {
      {  0,  48,  12,  60,   3,  51,  15,  63 },
      { 32,  16,  44,  28,  35,  19,  47,  31 },
      {  8,  56,   4,  52,  11,  59,   7,  55 },
      { 40,  24,  36,  20,  43,  27,  39,  23 },
      {  2,  50,  14,  62,   1,  49,  13,  61 },
      { 34,  18,  46,  30,  33,  17,  45,  29 },
      { 10,  58,   6,  54,   9,  57,   5,  53 },
      { 42,  26,  38,  22,  41,  25,  37,  21 },
  };
  
  static const double coeff[2][5] = {
      {
           0.6029490182363579  * M_SQRT2,
           0.2668641184428723  * M_SQRT2,
          -0.07822326652898785 * M_SQRT2,
          -0.01686411844287495 * M_SQRT2,
           0.02674875741080976 * M_SQRT2,
      },{
           1.115087052456994   / M_SQRT2,
          -0.5912717631142470  / M_SQRT2,
          -0.05754352622849957 / M_SQRT2,
           0.09127176311424948 / M_SQRT2,
      }
  };
  
  static const double icoeff[2][5] = {
      {
           1.115087052456994   / M_SQRT2,
           0.5912717631142470  / M_SQRT2,
          -0.05754352622849957 / M_SQRT2,
          -0.09127176311424948 / M_SQRT2,
      },{
           0.6029490182363579  * M_SQRT2,
          -0.2668641184428723  * M_SQRT2,
          -0.07822326652898785 * M_SQRT2,
           0.01686411844287495 * M_SQRT2,
           0.02674875741080976 * M_SQRT2,
      }
  };
  
  static inline int mirror(int x, int w)
  {
      while ((unsigned)x > (unsigned)w) {
          x = -x;
          if (x < 0)
              x += 2 * w;
      }
      return x;
  }
  
  static inline void decompose(float *dst_l, float *dst_h, const float *src,
                               int linesize, int w)
  {
      int x, i;
      for (x = 0; x < w; x++) {
          double sum_l = src[x * linesize] * coeff[0][0];
          double sum_h = src[x * linesize] * coeff[1][0];
          for (i = 1; i <= 4; i++) {
              const double s = src[mirror(x - i, w - 1) * linesize]
                             + src[mirror(x + i, w - 1) * linesize];
  
              sum_l += coeff[0][i] * s;
              sum_h += coeff[1][i] * s;
          }
          dst_l[x * linesize] = sum_l;
          dst_h[x * linesize] = sum_h;
      }
  }
  
  static inline void compose(float *dst, const float *src_l, const float *src_h,
                             int linesize, int w)
  {
      int x, i;
      for (x = 0; x < w; x++) {
          double sum_l = src_l[x * linesize] * icoeff[0][0];
          double sum_h = src_h[x * linesize] * icoeff[1][0];
          for (i = 1; i <= 4; i++) {
              const int x0 = mirror(x - i, w - 1) * linesize;
              const int x1 = mirror(x + i, w - 1) * linesize;
  
              sum_l += icoeff[0][i] * (src_l[x0] + src_l[x1]);
              sum_h += icoeff[1][i] * (src_h[x0] + src_h[x1]);
          }
          dst[x * linesize] = (sum_l + sum_h) * 0.5;
      }
  }
  
  static inline void decompose2D(float *dst_l, float *dst_h, const float *src,
                                 int xlinesize, int ylinesize,
                                 int step, int w, int h)
  {
      int y, x;
      for (y = 0; y < h; y++)
          for (x = 0; x < step; x++)
              decompose(dst_l + ylinesize*y + xlinesize*x,
                        dst_h + ylinesize*y + xlinesize*x,
                        src   + ylinesize*y + xlinesize*x,
                        step * xlinesize, (w - x + step - 1) / step);
  }
  
  static inline void compose2D(float *dst, const float *src_l, const float *src_h,
                               int xlinesize, int ylinesize,
                               int step, int w, int h)
  {
      int y, x;
      for (y = 0; y < h; y++)
          for (x = 0; x < step; x++)
              compose(dst   + ylinesize*y + xlinesize*x,
                      src_l + ylinesize*y + xlinesize*x,
                      src_h + ylinesize*y + xlinesize*x,
                      step * xlinesize, (w - x + step - 1) / step);
  }
  
  static void decompose2D2(float *dst[4], float *src, float *temp[2],
                           int linesize, int step, int w, int h)
  {
      decompose2D(temp[0], temp[1], src,     1, linesize, step, w, h);
      decompose2D( dst[0],  dst[1], temp[0], linesize, 1, step, h, w);
      decompose2D( dst[2],  dst[3], temp[1], linesize, 1, step, h, w);
  }
  
  static void compose2D2(float *dst, float *src[4], float *temp[2],
                         int linesize, int step, int w, int h)
  {
      compose2D(temp[0],  src[0],  src[1], linesize, 1, step, h, w);
      compose2D(temp[1],  src[2],  src[3], linesize, 1, step, h, w);
      compose2D(dst,     temp[0], temp[1], 1, linesize, step, w, h);
  }
  
  static void filter(OWDenoiseContext *s,
                     uint8_t       *dst, int dst_linesize,
                     const uint8_t *src, int src_linesize,
                     int width, int height, double strength)
  {
      int x, y, i, j, depth = s->depth;
  
      while (1<<depth > width || 1<<depth > height)
          depth--;
  
      for (y = 0; y < height; y++)
          for(x = 0; x < width; x++)
              s->plane[0][0][y*s->linesize + x] = src[y*src_linesize + x];
  
      for (i = 0; i < depth; i++)
          decompose2D2(s->plane[i + 1], s->plane[i][0], s->plane[0] + 1, s->linesize, 1<<i, width, height);
  
      for (i = 0; i < depth; i++) {
          for (j = 1; j < 4; j++) {
              for (y = 0; y < height; y++) {
                  for (x = 0; x < width; x++) {
                      double v = s->plane[i + 1][j][y*s->linesize + x];
                      if      (v >  strength) v -= strength;
                      else if (v < -strength) v += strength;
                      else                    v  = 0;
                      s->plane[i + 1][j][x + y*s->linesize] = v;
                  }
              }
          }
      }
      for (i = depth-1; i >= 0; i--)
          compose2D2(s->plane[i][0], s->plane[i + 1], s->plane[0] + 1, s->linesize, 1<<i, width, height);
  
      for (y = 0; y < height; y++) {
          for (x = 0; x < width; x++) {
              i = s->plane[0][0][y*s->linesize + x] + dither[x&7][y&7]*(1.0/64) + 1.0/128; // yes the rounding is insane but optimal :)
              if ((unsigned)i > 255U) i = ~(i >> 31);
              dst[y*dst_linesize + x] = i;
          }
      }
  }
  
  static int filter_frame(AVFilterLink *inlink, AVFrame *in)
  {
      int direct = 0;
      AVFilterContext *ctx = inlink->dst;
      OWDenoiseContext *s = ctx->priv;
      AVFilterLink *outlink = ctx->outputs[0];
      AVFrame *out;
      const int cw = FF_CEIL_RSHIFT(inlink->w, s->hsub);
      const int ch = FF_CEIL_RSHIFT(inlink->h, s->vsub);
  
      if (av_frame_is_writable(in)) {
          direct = 1;
          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);
      }
  
      filter(s, out->data[0], out->linesize[0], in->data[0], in->linesize[0], inlink->w, inlink->h, s->luma_strength);
      filter(s, out->data[1], out->linesize[1], in->data[1], in->linesize[1], cw,        ch,        s->chroma_strength);
      filter(s, out->data[2], out->linesize[2], in->data[2], in->linesize[2], cw,        ch,        s->chroma_strength);
  
      if (!direct) {
          if (in->data[3])
              av_image_copy_plane(out->data[3], out->linesize[3],
                                  in ->data[3], in ->linesize[3],
                                  inlink->w, inlink->h);
          av_frame_free(&in);
      }
  
      return ff_filter_frame(outlink, out);
  }
  
  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_NONE
      };
      ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
      return 0;
  }
  
  static int config_input(AVFilterLink *inlink)
  {
      int i, j;
      OWDenoiseContext *s = inlink->dst->priv;
      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
      const int h = FFALIGN(inlink->h, 16);
  
      s->hsub = desc->log2_chroma_w;
      s->vsub = desc->log2_chroma_h;
  
      s->linesize = FFALIGN(inlink->w, 16);
      for (j = 0; j < 4; j++) {
          for (i = 0; i <= s->depth; i++) {
              s->plane[i][j] = av_malloc(s->linesize * h * sizeof(s->plane[0][0][0]));
              if (!s->plane[i][j])
                  return AVERROR(ENOMEM);
          }
      }
      return 0;
  }
  
  static av_cold void uninit(AVFilterContext *ctx)
  {
      int i, j;
      OWDenoiseContext *s = ctx->priv;
  
      for (j = 0; j < 4; j++)
          for (i = 0; i <= s->depth; i++)
              av_freep(&s->plane[i][j]);
  }
  
  static const AVFilterPad owdenoise_inputs[] = {
      {
          .name         = "default",
          .type         = AVMEDIA_TYPE_VIDEO,
          .filter_frame = filter_frame,
          .config_props = config_input,
      },
      { NULL }
  };
  
  static const AVFilterPad owdenoise_outputs[] = {
       {
           .name = "default",
           .type = AVMEDIA_TYPE_VIDEO,
       },
       { NULL }
  };
  
  AVFilter avfilter_vf_owdenoise = {
      .name          = "owdenoise",
      .description   = NULL_IF_CONFIG_SMALL("Denoise using wavelets."),
      .priv_size     = sizeof(OWDenoiseContext),
      .uninit        = uninit,
      .query_formats = query_formats,
      .inputs        = owdenoise_inputs,
      .outputs       = owdenoise_outputs,
      .priv_class    = &owdenoise_class,
      .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
  };
  