text: /*
   * Copyright (C) 2012 British Broadcasting Corporation, All Rights Reserved
   * Author of de-interlace algorithm: Jim Easterbrook for BBC R&D
   * Based on the process described by Martin Weston for BBC R&D
   * Author of FFmpeg filter: Mark Himsley for BBC Broadcast Systems Development
   *
   * 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/common.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"
  #include "w3fdif.h"
  
  typedef struct W3FDIFContext {
      const AVClass *class;
      int filter;           ///< 0 is simple, 1 is more complex
      int deint;            ///< which frames to deinterlace
      int linesize[4];      ///< bytes of pixel data per line for each plane
      int planeheight[4];   ///< height of each plane
      int field;            ///< which field are we on, 0 or 1
      int eof;
      int nb_planes;
      AVFrame *prev, *cur, *next;  ///< previous, current, next frames
      int32_t **work_line;  ///< lines we are calculating
      int nb_threads;
  
      W3FDIFDSPContext dsp;
  } W3FDIFContext;
  
  #define OFFSET(x) offsetof(W3FDIFContext, x)
  #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
  #define CONST(name, help, val, unit) { name, help, 0, AV_OPT_TYPE_CONST, {.i64=val}, 0, 0, FLAGS, unit }
  
  static const AVOption w3fdif_options[] = {
      { "filter", "specify the filter", OFFSET(filter), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS, "filter" },
      CONST("simple",  NULL, 0, "filter"),
      CONST("complex", NULL, 1, "filter"),
      { "deint",  "specify which frames to deinterlace", OFFSET(deint), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "deint" },
      CONST("all",        "deinterlace all frames",                       0, "deint"),
      CONST("interlaced", "only deinterlace frames marked as interlaced", 1, "deint"),
      { NULL }
  };
  
  AVFILTER_DEFINE_CLASS(w3fdif);
  
  static int query_formats(AVFilterContext *ctx)
  {
      static const enum AVPixelFormat pix_fmts[] = {
          AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
          AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
          AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
          AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
          AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
          AV_PIX_FMT_YUVJ411P,
          AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA444P,
          AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,
          AV_PIX_FMT_GRAY8,
          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 void filter_simple_low(int32_t *work_line,
                                uint8_t *in_lines_cur[2],
                                const int16_t *coef, int linesize)
  {
      int i;
  
      for (i = 0; i < linesize; i++) {
          *work_line    = *in_lines_cur[0]++ * coef[0];
          *work_line++ += *in_lines_cur[1]++ * coef[1];
      }
  }
  
  static void filter_complex_low(int32_t *work_line,
                                 uint8_t *in_lines_cur[4],
                                 const int16_t *coef, int linesize)
  {
      int i;
  
      for (i = 0; i < linesize; i++) {
          *work_line    = *in_lines_cur[0]++ * coef[0];
          *work_line   += *in_lines_cur[1]++ * coef[1];
          *work_line   += *in_lines_cur[2]++ * coef[2];
          *work_line++ += *in_lines_cur[3]++ * coef[3];
      }
  }
  
  static void filter_simple_high(int32_t *work_line,
                                 uint8_t *in_lines_cur[3],
                                 uint8_t *in_lines_adj[3],
                                 const int16_t *coef, int linesize)
  {
      int i;
  
      for (i = 0; i < linesize; i++) {
          *work_line   += *in_lines_cur[0]++ * coef[0];
          *work_line   += *in_lines_adj[0]++ * coef[0];
          *work_line   += *in_lines_cur[1]++ * coef[1];
          *work_line   += *in_lines_adj[1]++ * coef[1];
          *work_line   += *in_lines_cur[2]++ * coef[2];
          *work_line++ += *in_lines_adj[2]++ * coef[2];
      }
  }
  
  static void filter_complex_high(int32_t *work_line,
                                  uint8_t *in_lines_cur[5],
                                  uint8_t *in_lines_adj[5],
                                  const int16_t *coef, int linesize)
  {
      int i;
  
      for (i = 0; i < linesize; i++) {
          *work_line   += *in_lines_cur[0]++ * coef[0];
          *work_line   += *in_lines_adj[0]++ * coef[0];
          *work_line   += *in_lines_cur[1]++ * coef[1];
          *work_line   += *in_lines_adj[1]++ * coef[1];
          *work_line   += *in_lines_cur[2]++ * coef[2];
          *work_line   += *in_lines_adj[2]++ * coef[2];
          *work_line   += *in_lines_cur[3]++ * coef[3];
          *work_line   += *in_lines_adj[3]++ * coef[3];
          *work_line   += *in_lines_cur[4]++ * coef[4];
          *work_line++ += *in_lines_adj[4]++ * coef[4];
      }
  }
  
  static void filter_scale(uint8_t *out_pixel, const int32_t *work_pixel, int linesize)
  {
      int j;
  
      for (j = 0; j < linesize; j++, out_pixel++, work_pixel++)
          *out_pixel = av_clip(*work_pixel, 0, 255 * 256 * 128) >> 15;
  }
  
  static int config_input(AVFilterLink *inlink)
  {
      AVFilterContext *ctx = inlink->dst;
      W3FDIFContext *s = ctx->priv;
      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
      int ret, i;
  
      if ((ret = av_image_fill_linesizes(s->linesize, inlink->format, inlink->w)) < 0)
          return ret;
  
      s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
      s->planeheight[0] = s->planeheight[3] = inlink->h;
  
      s->nb_planes = av_pix_fmt_count_planes(inlink->format);
      s->nb_threads = ff_filter_get_nb_threads(ctx);
      s->work_line = av_calloc(s->nb_threads, sizeof(*s->work_line));
      if (!s->work_line)
          return AVERROR(ENOMEM);
  
      for (i = 0; i < s->nb_threads; i++) {
          s->work_line[i] = av_calloc(FFALIGN(s->linesize[0], 32), sizeof(*s->work_line[0]));
          if (!s->work_line[i])
              return AVERROR(ENOMEM);
      }
  
      s->dsp.filter_simple_low   = filter_simple_low;
      s->dsp.filter_complex_low  = filter_complex_low;
      s->dsp.filter_simple_high  = filter_simple_high;
      s->dsp.filter_complex_high = filter_complex_high;
      s->dsp.filter_scale        = filter_scale;
  
      if (ARCH_X86)
          ff_w3fdif_init_x86(&s->dsp);
  
      return 0;
  }
  
  static int config_output(AVFilterLink *outlink)
  {
      AVFilterLink *inlink = outlink->src->inputs[0];
  
      outlink->time_base.num = inlink->time_base.num;
      outlink->time_base.den = inlink->time_base.den * 2;
      outlink->frame_rate.num = inlink->frame_rate.num * 2;
      outlink->frame_rate.den = inlink->frame_rate.den;
  
      return 0;
  }
  
  /*
   * Filter coefficients from PH-2071, scaled by 256 * 128.
   * Each set of coefficients has a set for low-frequencies and high-frequencies.
   * n_coef_lf[] and n_coef_hf[] are the number of coefs for simple and more-complex.
   * It is important for later that n_coef_lf[] is even and n_coef_hf[] is odd.
   * coef_lf[][] and coef_hf[][] are the coefficients for low-frequencies
   * and high-frequencies for simple and more-complex mode.
   */
  static const int8_t   n_coef_lf[2] = { 2, 4 };
  static const int16_t coef_lf[2][4] = {{ 16384, 16384,     0,    0},
                                        {  -852, 17236, 17236, -852}};
  static const int8_t   n_coef_hf[2] = { 3, 5 };
  static const int16_t coef_hf[2][5] = {{ -2048,  4096, -2048,     0,    0},
                                        {  1016, -3801,  5570, -3801, 1016}};
  
  typedef struct ThreadData {
      AVFrame *out, *cur, *adj;
      int plane;
  } ThreadData;
  
  static int deinterlace_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
  {
      W3FDIFContext *s = ctx->priv;
      ThreadData *td = arg;
      AVFrame *out = td->out;
      AVFrame *cur = td->cur;
      AVFrame *adj = td->adj;
      const int plane = td->plane;
      const int filter = s->filter;
      uint8_t *in_line, *in_lines_cur[5], *in_lines_adj[5];
      uint8_t *out_line, *out_pixel;
      int32_t *work_line, *work_pixel;
      uint8_t *cur_data = cur->data[plane];
      uint8_t *adj_data = adj->data[plane];
      uint8_t *dst_data = out->data[plane];
      const int linesize = s->linesize[plane];
      const int height   = s->planeheight[plane];
      const int cur_line_stride = cur->linesize[plane];
      const int adj_line_stride = adj->linesize[plane];
      const int dst_line_stride = out->linesize[plane];
      const int start = (height * jobnr) / nb_jobs;
      const int end = (height * (jobnr+1)) / nb_jobs;
      int j, y_in, y_out;
  
      /* copy unchanged the lines of the field */
      y_out = start + (s->field == cur->top_field_first) - (start & 1);
  
      in_line  = cur_data + (y_out * cur_line_stride);
      out_line = dst_data + (y_out * dst_line_stride);
  
      while (y_out < end) {
          memcpy(out_line, in_line, linesize);
          y_out += 2;
          in_line  += cur_line_stride * 2;
          out_line += dst_line_stride * 2;
      }
  
      /* interpolate other lines of the field */
      y_out = start + (s->field != cur->top_field_first) - (start & 1);
  
      out_line = dst_data + (y_out * dst_line_stride);
  
      while (y_out < end) {
          /* get low vertical frequencies from current field */
          for (j = 0; j < n_coef_lf[filter]; j++) {
              y_in = (y_out + 1) + (j * 2) - n_coef_lf[filter];
  
              while (y_in < 0)
                  y_in += 2;
              while (y_in >= height)
                  y_in -= 2;
  
              in_lines_cur[j] = cur_data + (y_in * cur_line_stride);
          }
  
          work_line = s->work_line[jobnr];
          switch (n_coef_lf[filter]) {
          case 2:
              s->dsp.filter_simple_low(work_line, in_lines_cur,
                                       coef_lf[filter], linesize);
              break;
          case 4:
              s->dsp.filter_complex_low(work_line, in_lines_cur,
                                        coef_lf[filter], linesize);
          }
  
          /* get high vertical frequencies from adjacent fields */
          for (j = 0; j < n_coef_hf[filter]; j++) {
              y_in = (y_out + 1) + (j * 2) - n_coef_hf[filter];
  
              while (y_in < 0)
                  y_in += 2;
              while (y_in >= height)
                  y_in -= 2;
  
              in_lines_cur[j] = cur_data + (y_in * cur_line_stride);
              in_lines_adj[j] = adj_data + (y_in * adj_line_stride);
          }
  
          work_line = s->work_line[jobnr];
          switch (n_coef_hf[filter]) {
          case 3:
              s->dsp.filter_simple_high(work_line, in_lines_cur, in_lines_adj,
                                        coef_hf[filter], linesize);
              break;
          case 5:
              s->dsp.filter_complex_high(work_line, in_lines_cur, in_lines_adj,
                                         coef_hf[filter], linesize);
          }
  
          /* save scaled result to the output frame, scaling down by 256 * 128 */
          work_pixel = s->work_line[jobnr];
          out_pixel = out_line;
  
          s->dsp.filter_scale(out_pixel, work_pixel, linesize);
  
          /* move on to next line */
          y_out += 2;
          out_line += dst_line_stride * 2;
      }
  
      return 0;
  }
  
  static int filter(AVFilterContext *ctx, int is_second)
  {
      W3FDIFContext *s = ctx->priv;
      AVFilterLink *outlink = ctx->outputs[0];
      AVFrame *out, *adj;
      ThreadData td;
      int plane;
  
      out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
      if (!out)
          return AVERROR(ENOMEM);
      av_frame_copy_props(out, s->cur);
      out->interlaced_frame = 0;
  
      if (!is_second) {
          if (out->pts != AV_NOPTS_VALUE)
              out->pts *= 2;
      } else {
          int64_t cur_pts  = s->cur->pts;
          int64_t next_pts = s->next->pts;
  
          if (next_pts != AV_NOPTS_VALUE && cur_pts != AV_NOPTS_VALUE) {
              out->pts = cur_pts + next_pts;
          } else {
              out->pts = AV_NOPTS_VALUE;
          }
      }
  
      adj = s->field ? s->next : s->prev;
      td.out = out; td.cur = s->cur; td.adj = adj;
      for (plane = 0; plane < s->nb_planes; plane++) {
          td.plane = plane;
          ctx->internal->execute(ctx, deinterlace_slice, &td, NULL, FFMIN(s->planeheight[plane], s->nb_threads));
      }
  
      s->field = !s->field;
  
      return ff_filter_frame(outlink, out);
  }
  
  static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
  {
      AVFilterContext *ctx = inlink->dst;
      W3FDIFContext *s = ctx->priv;
      int ret;
  
      av_frame_free(&s->prev);
      s->prev = s->cur;
      s->cur  = s->next;
      s->next = frame;
  
      if (!s->cur) {
          s->cur = av_frame_clone(s->next);
          if (!s->cur)
              return AVERROR(ENOMEM);
      }
  
      if ((s->deint && !s->cur->interlaced_frame) || ctx->is_disabled) {
          AVFrame *out = av_frame_clone(s->cur);
          if (!out)
              return AVERROR(ENOMEM);
  
          av_frame_free(&s->prev);
          if (out->pts != AV_NOPTS_VALUE)
              out->pts *= 2;
          return ff_filter_frame(ctx->outputs[0], out);
      }
  
      if (!s->prev)
          return 0;
  
      ret = filter(ctx, 0);
      if (ret < 0)
          return ret;
  
      return filter(ctx, 1);
  }
  
  static int request_frame(AVFilterLink *outlink)
  {
      AVFilterContext *ctx = outlink->src;
      W3FDIFContext *s = ctx->priv;
      int ret;
  
      if (s->eof)
          return AVERROR_EOF;
  
      ret = ff_request_frame(ctx->inputs[0]);
  
      if (ret == AVERROR_EOF && s->cur) {
          AVFrame *next = av_frame_clone(s->next);
          if (!next)
              return AVERROR(ENOMEM);
          next->pts = s->next->pts * 2 - s->cur->pts;
          filter_frame(ctx->inputs[0], next);
          s->eof = 1;
      } else if (ret < 0) {
          return ret;
      }
  
      return 0;
  }
  
  static av_cold void uninit(AVFilterContext *ctx)
  {
      W3FDIFContext *s = ctx->priv;
      int i;
  
      av_frame_free(&s->prev);
      av_frame_free(&s->cur );
      av_frame_free(&s->next);
  
      for (i = 0; i < s->nb_threads; i++)
          av_freep(&s->work_line[i]);
  
      av_freep(&s->work_line);
  }
  
  static const AVFilterPad w3fdif_inputs[] = {
      {
          .name          = "default",
          .type          = AVMEDIA_TYPE_VIDEO,
          .filter_frame  = filter_frame,
          .config_props  = config_input,
      },
      { NULL }
  };
  
  static const AVFilterPad w3fdif_outputs[] = {
      {
          .name          = "default",
          .type          = AVMEDIA_TYPE_VIDEO,
          .config_props  = config_output,
          .request_frame = request_frame,
      },
      { NULL }
  };
  
  AVFilter ff_vf_w3fdif = {
      .name          = "w3fdif",
      .description   = NULL_IF_CONFIG_SMALL("Apply Martin Weston three field deinterlace."),
      .priv_size     = sizeof(W3FDIFContext),
      .priv_class    = &w3fdif_class,
      .uninit        = uninit,
      .query_formats = query_formats,
      .inputs        = w3fdif_inputs,
      .outputs       = w3fdif_outputs,
      .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL | AVFILTER_FLAG_SLICE_THREADS,
  };
  