text: /*
   * Copyright (c) 2015 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/parseutils.h"
  #include "libavutil/pixdesc.h"
  
  #include "avfilter.h"
  #include "drawutils.h"
  #include "formats.h"
  #include "internal.h"
  #include "framesync.h"
  #include "video.h"
  
  typedef struct StackItem {
      int x[4], y[4];
      int linesize[4];
      int height[4];
  } StackItem;
  
  typedef struct StackContext {
      const AVClass *class;
      const AVPixFmtDescriptor *desc;
      int nb_inputs;
      char *layout;
      int shortest;
      int is_vertical;
      int is_horizontal;
      int nb_planes;
      uint8_t fillcolor[4];
      char *fillcolor_str;
      int fillcolor_enable;
  
      FFDrawContext draw;
      FFDrawColor color;
  
      StackItem *items;
      AVFrame **frames;
      FFFrameSync fs;
  } StackContext;
  
  static int query_formats(AVFilterContext *ctx)
  {
      AVFilterFormats *pix_fmts = NULL;
      StackContext *s = ctx->priv;
      int fmt, ret;
  
      if (s->fillcolor_enable) {
          return ff_set_common_formats(ctx, ff_draw_supported_pixel_formats(0));
      }
  
      for (fmt = 0; av_pix_fmt_desc_get(fmt); fmt++) {
          const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
          if (!(desc->flags & AV_PIX_FMT_FLAG_PAL ||
                desc->flags & AV_PIX_FMT_FLAG_HWACCEL ||
                desc->flags & AV_PIX_FMT_FLAG_BITSTREAM) &&
              (ret = ff_add_format(&pix_fmts, fmt)) < 0)
              return ret;
      }
  
      return ff_set_common_formats(ctx, pix_fmts);
  }
  
  static av_cold int init(AVFilterContext *ctx)
  {
      StackContext *s = ctx->priv;
      int i, ret;
  
      if (!strcmp(ctx->filter->name, "vstack"))
          s->is_vertical = 1;
  
      if (!strcmp(ctx->filter->name, "hstack"))
          s->is_horizontal = 1;
  
      s->frames = av_calloc(s->nb_inputs, sizeof(*s->frames));
      if (!s->frames)
          return AVERROR(ENOMEM);
  
      s->items = av_calloc(s->nb_inputs, sizeof(*s->items));
      if (!s->items)
          return AVERROR(ENOMEM);
  
      if (!strcmp(ctx->filter->name, "xstack")) {
          if (strcmp(s->fillcolor_str, "none") &&
              av_parse_color(s->fillcolor, s->fillcolor_str, -1, ctx) >= 0) {
              s->fillcolor_enable = 1;
          } else {
              s->fillcolor_enable = 0;
          }
          if (!s->layout) {
              if (s->nb_inputs == 2) {
                  s->layout = av_strdup("0_0|w0_0");
                  if (!s->layout)
                      return AVERROR(ENOMEM);
              } else {
                  av_log(ctx, AV_LOG_ERROR, "No layout specified.\n");
                  return AVERROR(EINVAL);
              }
          }
      }
  
      for (i = 0; i < s->nb_inputs; i++) {
          AVFilterPad pad = { 0 };
  
          pad.type = AVMEDIA_TYPE_VIDEO;
          pad.name = av_asprintf("input%d", i);
          if (!pad.name)
              return AVERROR(ENOMEM);
  
          if ((ret = ff_insert_inpad(ctx, i, &pad)) < 0) {
              av_freep(&pad.name);
              return ret;
          }
      }
  
      return 0;
  }
  
  static int process_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
  {
      StackContext *s = ctx->priv;
      AVFrame *out = arg;
      AVFrame **in = s->frames;
      const int start = (s->nb_inputs *  job   ) / nb_jobs;
      const int end   = (s->nb_inputs * (job+1)) / nb_jobs;
  
      for (int i = start; i < end; i++) {
          StackItem *item = &s->items[i];
  
          for (int p = 0; p < s->nb_planes; p++) {
              av_image_copy_plane(out->data[p] + out->linesize[p] * item->y[p] + item->x[p],
                                  out->linesize[p],
                                  in[i]->data[p],
                                  in[i]->linesize[p],
                                  item->linesize[p], item->height[p]);
          }
      }
  
      return 0;
  }
  
  static int process_frame(FFFrameSync *fs)
  {
      AVFilterContext *ctx = fs->parent;
      AVFilterLink *outlink = ctx->outputs[0];
      StackContext *s = fs->opaque;
      AVFrame **in = s->frames;
      AVFrame *out;
      int i, ret;
  
      for (i = 0; i < s->nb_inputs; i++) {
          if ((ret = ff_framesync_get_frame(&s->fs, i, &in[i], 0)) < 0)
              return ret;
      }
  
      out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
      if (!out)
          return AVERROR(ENOMEM);
      out->pts = av_rescale_q(s->fs.pts, s->fs.time_base, outlink->time_base);
      out->sample_aspect_ratio = outlink->sample_aspect_ratio;
  
      if (s->fillcolor_enable)
          ff_fill_rectangle(&s->draw, &s->color, out->data, out->linesize,
                            0, 0, outlink->w, outlink->h);
  
      ctx->internal->execute(ctx, process_slice, out, NULL, FFMIN(s->nb_inputs, ff_filter_get_nb_threads(ctx)));
  
      return ff_filter_frame(outlink, out);
  }
  
  static int config_output(AVFilterLink *outlink)
  {
      AVFilterContext *ctx = outlink->src;
      StackContext *s = ctx->priv;
      AVRational frame_rate = ctx->inputs[0]->frame_rate;
      AVRational sar = ctx->inputs[0]->sample_aspect_ratio;
      int height = ctx->inputs[0]->h;
      int width = ctx->inputs[0]->w;
      FFFrameSyncIn *in;
      int i, ret;
  
      s->desc = av_pix_fmt_desc_get(outlink->format);
      if (!s->desc)
          return AVERROR_BUG;
  
      if (s->is_vertical) {
          for (i = 0; i < s->nb_inputs; i++) {
              AVFilterLink *inlink = ctx->inputs[i];
              StackItem *item = &s->items[i];
  
              if (ctx->inputs[i]->w != width) {
                  av_log(ctx, AV_LOG_ERROR, "Input %d width %d does not match input %d width %d.\n", i, ctx->inputs[i]->w, 0, width);
                  return AVERROR(EINVAL);
              }
  
              if ((ret = av_image_fill_linesizes(item->linesize, inlink->format, inlink->w)) < 0) {
                  return ret;
              }
  
              item->height[1] = item->height[2] = AV_CEIL_RSHIFT(inlink->h, s->desc->log2_chroma_h);
              item->height[0] = item->height[3] = inlink->h;
  
              if (i) {
                  item->y[1] = item->y[2] = AV_CEIL_RSHIFT(height, s->desc->log2_chroma_h);
                  item->y[0] = item->y[3] = height;
  
                  height += ctx->inputs[i]->h;
              }
          }
      } else if (s->is_horizontal) {
          for (i = 0; i < s->nb_inputs; i++) {
              AVFilterLink *inlink = ctx->inputs[i];
              StackItem *item = &s->items[i];
  
              if (ctx->inputs[i]->h != height) {
                  av_log(ctx, AV_LOG_ERROR, "Input %d height %d does not match input %d height %d.\n", i, ctx->inputs[i]->h, 0, height);
                  return AVERROR(EINVAL);
              }
  
              if ((ret = av_image_fill_linesizes(item->linesize, inlink->format, inlink->w)) < 0) {
                  return ret;
              }
  
              item->height[1] = item->height[2] = AV_CEIL_RSHIFT(inlink->h, s->desc->log2_chroma_h);
              item->height[0] = item->height[3] = inlink->h;
  
              if (i) {
                  if ((ret = av_image_fill_linesizes(item->x, inlink->format, width)) < 0) {
                      return ret;
                  }
  
                  width += ctx->inputs[i]->w;
              }
          }
      } else {
          char *arg, *p = s->layout, *saveptr = NULL;
          char *arg2, *p2, *saveptr2 = NULL;
          char *arg3, *p3, *saveptr3 = NULL;
          int inw, inh, size;
  
          if (s->fillcolor_enable) {
              ff_draw_init(&s->draw, ctx->inputs[0]->format, 0);
              ff_draw_color(&s->draw, &s->color, s->fillcolor);
          }
  
          for (i = 0; i < s->nb_inputs; i++) {
              AVFilterLink *inlink = ctx->inputs[i];
              StackItem *item = &s->items[i];
  
              if (!(arg = av_strtok(p, "|", &saveptr)))
                  return AVERROR(EINVAL);
  
              p = NULL;
  
              if ((ret = av_image_fill_linesizes(item->linesize, inlink->format, inlink->w)) < 0) {
                  return ret;
              }
  
              item->height[1] = item->height[2] = AV_CEIL_RSHIFT(inlink->h, s->desc->log2_chroma_h);
              item->height[0] = item->height[3] = inlink->h;
  
              p2 = arg;
              inw = inh = 0;
  
              for (int j = 0; j < 2; j++) {
                  if (!(arg2 = av_strtok(p2, "_", &saveptr2)))
                      return AVERROR(EINVAL);
  
                  p2 = NULL;
                  p3 = arg2;
                  while ((arg3 = av_strtok(p3, "+", &saveptr3))) {
                      p3 = NULL;
                      if (sscanf(arg3, "w%d", &size) == 1) {
                          if (size == i || size < 0 || size >= s->nb_inputs)
                              return AVERROR(EINVAL);
  
                          if (!j)
                              inw += ctx->inputs[size]->w;
                          else
                              inh += ctx->inputs[size]->w;
                      } else if (sscanf(arg3, "h%d", &size) == 1) {
                          if (size == i || size < 0 || size >= s->nb_inputs)
                              return AVERROR(EINVAL);
  
                          if (!j)
                              inw += ctx->inputs[size]->h;
                          else
                              inh += ctx->inputs[size]->h;
                      } else if (sscanf(arg3, "%d", &size) == 1) {
                          if (size < 0)
                              return AVERROR(EINVAL);
  
                          if (!j)
                              inw += size;
                          else
                              inh += size;
                      } else {
                          return AVERROR(EINVAL);
                      }
                  }
              }
  
              if ((ret = av_image_fill_linesizes(item->x, inlink->format, inw)) < 0) {
                  return ret;
              }
  
              item->y[1] = item->y[2] = AV_CEIL_RSHIFT(inh, s->desc->log2_chroma_h);
              item->y[0] = item->y[3] = inh;
  
              width  = FFMAX(width,  inlink->w + inw);
              height = FFMAX(height, inlink->h + inh);
          }
      }
  
      s->nb_planes = av_pix_fmt_count_planes(outlink->format);
  
      outlink->w          = width;
      outlink->h          = height;
      outlink->frame_rate = frame_rate;
      outlink->sample_aspect_ratio = sar;
  
      for (i = 1; i < s->nb_inputs; i++) {
          AVFilterLink *inlink = ctx->inputs[i];
          if (outlink->frame_rate.num != inlink->frame_rate.num ||
              outlink->frame_rate.den != inlink->frame_rate.den) {
              av_log(ctx, AV_LOG_VERBOSE,
                      "Video inputs have different frame rates, output will be VFR\n");
              outlink->frame_rate = av_make_q(1, 0);
              break;
          }
      }
  
      if ((ret = ff_framesync_init(&s->fs, ctx, s->nb_inputs)) < 0)
          return ret;
  
      in = s->fs.in;
      s->fs.opaque = s;
      s->fs.on_event = process_frame;
  
      for (i = 0; i < s->nb_inputs; i++) {
          AVFilterLink *inlink = ctx->inputs[i];
  
          in[i].time_base = inlink->time_base;
          in[i].sync   = 1;
          in[i].before = EXT_STOP;
          in[i].after  = s->shortest ? EXT_STOP : EXT_INFINITY;
      }
  
      ret = ff_framesync_configure(&s->fs);
      outlink->time_base = s->fs.time_base;
  
      return ret;
  }
  
  static av_cold void uninit(AVFilterContext *ctx)
  {
      StackContext *s = ctx->priv;
      int i;
  
      ff_framesync_uninit(&s->fs);
      av_freep(&s->frames);
      av_freep(&s->items);
  
      for (i = 0; i < ctx->nb_inputs; i++)
          av_freep(&ctx->input_pads[i].name);
  }
  
  static int activate(AVFilterContext *ctx)
  {
      StackContext *s = ctx->priv;
      return ff_framesync_activate(&s->fs);
  }
  
  #define OFFSET(x) offsetof(StackContext, x)
  #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
  static const AVOption stack_options[] = {
      { "inputs", "set number of inputs", OFFSET(nb_inputs), AV_OPT_TYPE_INT, {.i64=2}, 2, INT_MAX, .flags = FLAGS },
      { "shortest", "force termination when the shortest input terminates", OFFSET(shortest), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, .flags = FLAGS },
      { NULL },
  };
  
  static const AVFilterPad outputs[] = {
      {
          .name          = "default",
          .type          = AVMEDIA_TYPE_VIDEO,
          .config_props  = config_output,
      },
      { NULL }
  };
  
  #if CONFIG_HSTACK_FILTER
  
  #define hstack_options stack_options
  AVFILTER_DEFINE_CLASS(hstack);
  
  AVFilter ff_vf_hstack = {
      .name          = "hstack",
      .description   = NULL_IF_CONFIG_SMALL("Stack video inputs horizontally."),
      .priv_size     = sizeof(StackContext),
      .priv_class    = &hstack_class,
      .query_formats = query_formats,
      .outputs       = outputs,
      .init          = init,
      .uninit        = uninit,
      .activate      = activate,
      .flags         = AVFILTER_FLAG_DYNAMIC_INPUTS | AVFILTER_FLAG_SLICE_THREADS,
  };
  
  #endif /* CONFIG_HSTACK_FILTER */
  
  #if CONFIG_VSTACK_FILTER
  
  #define vstack_options stack_options
  AVFILTER_DEFINE_CLASS(vstack);
  
  AVFilter ff_vf_vstack = {
      .name          = "vstack",
      .description   = NULL_IF_CONFIG_SMALL("Stack video inputs vertically."),
      .priv_size     = sizeof(StackContext),
      .priv_class    = &vstack_class,
      .query_formats = query_formats,
      .outputs       = outputs,
      .init          = init,
      .uninit        = uninit,
      .activate      = activate,
      .flags         = AVFILTER_FLAG_DYNAMIC_INPUTS | AVFILTER_FLAG_SLICE_THREADS,
  };
  
  #endif /* CONFIG_VSTACK_FILTER */
  
  #if CONFIG_XSTACK_FILTER
  
  static const AVOption xstack_options[] = {
      { "inputs", "set number of inputs", OFFSET(nb_inputs), AV_OPT_TYPE_INT, {.i64=2}, 2, INT_MAX, .flags = FLAGS },
      { "layout", "set custom layout", OFFSET(layout), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, .flags = FLAGS },
      { "shortest", "force termination when the shortest input terminates", OFFSET(shortest), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, .flags = FLAGS },
      { "fill",  "set the color for unused pixels", OFFSET(fillcolor_str), AV_OPT_TYPE_STRING, {.str = "none"}, .flags = FLAGS },
      { NULL },
  };
  
  AVFILTER_DEFINE_CLASS(xstack);
  
  AVFilter ff_vf_xstack = {
      .name          = "xstack",
      .description   = NULL_IF_CONFIG_SMALL("Stack video inputs into custom layout."),
      .priv_size     = sizeof(StackContext),
      .priv_class    = &xstack_class,
      .query_formats = query_formats,
      .outputs       = outputs,
      .init          = init,
      .uninit        = uninit,
      .activate      = activate,
      .flags         = AVFILTER_FLAG_DYNAMIC_INPUTS | AVFILTER_FLAG_SLICE_THREADS,
  };
  
  #endif /* CONFIG_XSTACK_FILTER */
  