text: /*
   * Original copyright (c) 2002 Remi Guyomarch <rguyom@pobox.com>
   * Port copyright (c) 2010 Daniel G. Taylor <dan@programmer-art.org>
   * Relicensed to the LGPL with permission from Remi Guyomarch.
   *
   * 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
   * blur / sharpen filter, ported to FFmpeg from MPlayer
   * libmpcodecs/unsharp.c.
   *
   * This code is based on:
   *
   * An Efficient algorithm for Gaussian blur using finite-state machines
   * Frederick M. Waltz and John W. V. Miller
   *
   * SPIE Conf. on Machine Vision Systems for Inspection and Metrology VII
   * Originally published Boston, Nov 98
   *
   * http://www.engin.umd.umich.edu/~jwvm/ece581/21_GBlur.pdf
   */
  
  #include "avfilter.h"
  #include "libavutil/common.h"
  #include "libavutil/mem.h"
  #include "libavutil/pixdesc.h"
  
  #define MIN_SIZE 3
  #define MAX_SIZE 13
  
  #define CHROMA_WIDTH(link)  -((-link->w) >> av_pix_fmt_descriptors[link->format].log2_chroma_w)
  #define CHROMA_HEIGHT(link) -((-link->h) >> av_pix_fmt_descriptors[link->format].log2_chroma_h)
  
  typedef struct FilterParam {
      int msize_x;                             ///< matrix width
      int msize_y;                             ///< matrix height
      int amount;                              ///< effect amount
      int steps_x;                             ///< horizontal step count
      int steps_y;                             ///< vertical step count
      int scalebits;                           ///< bits to shift pixel
      int32_t halfscale;                       ///< amount to add to pixel
      uint32_t *sc[(MAX_SIZE * MAX_SIZE) - 1]; ///< finite state machine storage
  } FilterParam;
  
  typedef struct {
      FilterParam luma;   ///< luma parameters (width, height, amount)
      FilterParam chroma; ///< chroma parameters (width, height, amount)
  } UnsharpContext;
  
  static void unsharpen(uint8_t *dst, const uint8_t *src, int dst_stride, int src_stride, int width, int height, FilterParam *fp)
  {
      uint32_t **sc = fp->sc;
      uint32_t sr[(MAX_SIZE * MAX_SIZE) - 1], tmp1, tmp2;
  
      int32_t res;
      int x, y, z;
  
      if (!fp->amount) {
          if (dst_stride == src_stride)
              memcpy(dst, src, src_stride * height);
          else
              for (y = 0; y < height; y++, dst += dst_stride, src += src_stride)
                  memcpy(dst, src, width);
          return;
      }
  
      for (y = 0; y < 2 * fp->steps_y; y++)
          memset(sc[y], 0, sizeof(sc[y][0]) * (width + 2 * fp->steps_x));
  
      for (y = -fp->steps_y; y < height + fp->steps_y; y++) {
          memset(sr, 0, sizeof(sr[0]) * (2 * fp->steps_x - 1));
          for (x = -fp->steps_x; x < width + fp->steps_x; x++) {
              tmp1 = x <= 0 ? src[0] : x >= width ? src[width-1] : src[x];
              for (z = 0; z < fp->steps_x * 2; z += 2) {
                  tmp2 = sr[z + 0] + tmp1; sr[z + 0] = tmp1;
                  tmp1 = sr[z + 1] + tmp2; sr[z + 1] = tmp2;
              }
              for (z = 0; z < fp->steps_y * 2; z += 2) {
                  tmp2 = sc[z + 0][x + fp->steps_x] + tmp1; sc[z + 0][x + fp->steps_x] = tmp1;
                  tmp1 = sc[z + 1][x + fp->steps_x] + tmp2; sc[z + 1][x + fp->steps_x] = tmp2;
              }
              if (x >= fp->steps_x && y >= fp->steps_y) {
                  const uint8_t* srx = src - fp->steps_y * src_stride + x - fp->steps_x;
                  uint8_t* dsx = dst - fp->steps_y * dst_stride + x - fp->steps_x;
  
                  res = (int32_t)*srx + ((((int32_t) * srx - (int32_t)((tmp1 + fp->halfscale) >> fp->scalebits)) * fp->amount) >> 16);
                  *dsx = av_clip_uint8(res);
              }
          }
          if (y >= 0) {
              dst += dst_stride;
              src += src_stride;
          }
      }
  }
  
  static void set_filter_param(FilterParam *fp, int msize_x, int msize_y, double amount)
  {
      fp->msize_x = msize_x;
      fp->msize_y = msize_y;
      fp->amount = amount * 65536.0;
  
      fp->steps_x = msize_x / 2;
      fp->steps_y = msize_y / 2;
      fp->scalebits = (fp->steps_x + fp->steps_y) * 2;
      fp->halfscale = 1 << (fp->scalebits - 1);
  }
  
  static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
  {
      UnsharpContext *unsharp = ctx->priv;
      int lmsize_x = 5, cmsize_x = 0;
      int lmsize_y = 5, cmsize_y = 0;
      double lamount = 1.0f, camount = 0.0f;
  
      if (args)
          sscanf(args, "%d:%d:%lf:%d:%d:%lf", &lmsize_x, &lmsize_y, &lamount,
                                              &cmsize_x, &cmsize_y, &camount);
  
      if ((lamount && (lmsize_x < 2 || lmsize_y < 2)) ||
          (camount && (cmsize_x < 2 || cmsize_y < 2))) {
          av_log(ctx, AV_LOG_ERROR,
                 "Invalid value <2 for lmsize_x:%d or lmsize_y:%d or cmsize_x:%d or cmsize_y:%d\n",
                 lmsize_x, lmsize_y, cmsize_x, cmsize_y);
          return AVERROR(EINVAL);
      }
  
      set_filter_param(&unsharp->luma,   lmsize_x, lmsize_y, lamount);
      set_filter_param(&unsharp->chroma, cmsize_x, cmsize_y, camount);
  
      return 0;
  }
  
  static int query_formats(AVFilterContext *ctx)
  {
      enum PixelFormat pix_fmts[] = {
          PIX_FMT_YUV420P,  PIX_FMT_YUV422P,  PIX_FMT_YUV444P,  PIX_FMT_YUV410P,
          PIX_FMT_YUV411P,  PIX_FMT_YUV440P,  PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P,
          PIX_FMT_YUVJ444P, PIX_FMT_YUVJ440P, PIX_FMT_NONE
      };
  
      avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));
  
      return 0;
  }
  
  static void init_filter_param(AVFilterContext *ctx, FilterParam *fp, const char *effect_type, int width)
  {
      int z;
      const char *effect;
  
      effect = fp->amount == 0 ? "none" : fp->amount < 0 ? "blur" : "sharpen";
  
      av_log(ctx, AV_LOG_INFO, "effect:%s type:%s msize_x:%d msize_y:%d amount:%0.2f\n",
             effect, effect_type, fp->msize_x, fp->msize_y, fp->amount / 65535.0);
  
      for (z = 0; z < 2 * fp->steps_y; z++)
          fp->sc[z] = av_malloc(sizeof(*(fp->sc[z])) * (width + 2 * fp->steps_x));
  }
  
  static int config_props(AVFilterLink *link)
  {
      UnsharpContext *unsharp = link->dst->priv;
  
      init_filter_param(link->dst, &unsharp->luma,   "luma",   link->w);
      init_filter_param(link->dst, &unsharp->chroma, "chroma", CHROMA_WIDTH(link));
  
      return 0;
  }
  
  static void free_filter_param(FilterParam *fp)
  {
      int z;
  
      for (z = 0; z < 2 * fp->steps_y; z++)
          av_free(fp->sc[z]);
  }
  
  static av_cold void uninit(AVFilterContext *ctx)
  {
      UnsharpContext *unsharp = ctx->priv;
  
      free_filter_param(&unsharp->luma);
      free_filter_param(&unsharp->chroma);
  }
  
  static void end_frame(AVFilterLink *link)
  {
      UnsharpContext *unsharp = link->dst->priv;
      AVFilterBufferRef *in  = link->cur_buf;
      AVFilterBufferRef *out = link->dst->outputs[0]->out_buf;
  
      unsharpen(out->data[0], in->data[0], out->linesize[0], in->linesize[0], link->w,            link->h,             &unsharp->luma);
      unsharpen(out->data[1], in->data[1], out->linesize[1], in->linesize[1], CHROMA_WIDTH(link), CHROMA_HEIGHT(link), &unsharp->chroma);
      unsharpen(out->data[2], in->data[2], out->linesize[2], in->linesize[2], CHROMA_WIDTH(link), CHROMA_HEIGHT(link), &unsharp->chroma);
  
      avfilter_unref_buffer(in);
      avfilter_draw_slice(link->dst->outputs[0], 0, link->h, 1);
      avfilter_end_frame(link->dst->outputs[0]);
      avfilter_unref_buffer(out);
  }
  
  static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
  {
  }
  
  AVFilter avfilter_vf_unsharp = {
      .name      = "unsharp",
      .description = NULL_IF_CONFIG_SMALL("Sharpen or blur the input video."),
  
      .priv_size = sizeof(UnsharpContext),
  
      .init = init,
      .uninit = uninit,
      .query_formats = query_formats,
  
      .inputs    = (AVFilterPad[]) {{ .name             = "default",
                                      .type             = AVMEDIA_TYPE_VIDEO,
                                      .draw_slice       = draw_slice,
                                      .end_frame        = end_frame,
                                      .config_props     = config_props,
                                      .min_perms        = AV_PERM_READ, },
                                    { .name = NULL}},
  
      .outputs   = (AVFilterPad[]) {{ .name             = "default",
                                      .type             = AVMEDIA_TYPE_VIDEO, },
                                    { .name = NULL}},
  };
  