text: /*
   * Copyright (c) 2011 Baptiste Coudurier
   * Copyright (c) 2011 Stefano Sabatini
   * Copyright (c) 2012 Clément Bœsch
   *
   * 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
   * Libass subtitles burning filter.
   *
   * @see{http://www.matroska.org/technical/specs/subtitles/ssa.html}
   */
  
  #include <ass/ass.h>
  
  #include "config.h"
  #if CONFIG_SUBTITLES_FILTER
  # include "libavcodec/avcodec.h"
  # include "libavformat/avformat.h"
  #endif
  #include "libavutil/avstring.h"
  #include "libavutil/imgutils.h"
  #include "libavutil/opt.h"
  #include "libavutil/parseutils.h"
  #include "drawutils.h"
  #include "avfilter.h"
  #include "internal.h"
  #include "formats.h"
  #include "video.h"
  
  typedef struct AssContext {
      const AVClass *class;
      ASS_Library  *library;
      ASS_Renderer *renderer;
      ASS_Track    *track;
      char *filename;
      char *fontsdir;
      char *charenc;
      char *force_style;
      int stream_index;
      int alpha;
      uint8_t rgba_map[4];
      int     pix_step[4];       ///< steps per pixel for each plane of the main output
      int original_w, original_h;
      int shaping;
      FFDrawContext draw;
  } AssContext;
  
  #define OFFSET(x) offsetof(AssContext, x)
  #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
  
  #define COMMON_OPTIONS \
      {"filename",       "set the filename of file to read",                         OFFSET(filename),   AV_OPT_TYPE_STRING,     {.str = NULL},  CHAR_MIN, CHAR_MAX, FLAGS }, \
      {"f",              "set the filename of file to read",                         OFFSET(filename),   AV_OPT_TYPE_STRING,     {.str = NULL},  CHAR_MIN, CHAR_MAX, FLAGS }, \
      {"original_size",  "set the size of the original video (used to scale fonts)", OFFSET(original_w), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL},  CHAR_MIN, CHAR_MAX, FLAGS }, \
      {"fontsdir",       "set the directory containing the fonts to read",           OFFSET(fontsdir),   AV_OPT_TYPE_STRING,     {.str = NULL},  CHAR_MIN, CHAR_MAX, FLAGS }, \
      {"alpha",          "enable processing of alpha channel",                       OFFSET(alpha),      AV_OPT_TYPE_BOOL,       {.i64 = 0   },         0,        1, FLAGS }, \
  
  /* libass supports a log level ranging from 0 to 7 */
  static const int ass_libavfilter_log_level_map[] = {
      [0] = AV_LOG_FATAL,     /* MSGL_FATAL */
      [1] = AV_LOG_ERROR,     /* MSGL_ERR */
      [2] = AV_LOG_WARNING,   /* MSGL_WARN */
      [3] = AV_LOG_WARNING,   /* <undefined> */
      [4] = AV_LOG_INFO,      /* MSGL_INFO */
      [5] = AV_LOG_INFO,      /* <undefined> */
      [6] = AV_LOG_VERBOSE,   /* MSGL_V */
      [7] = AV_LOG_DEBUG,     /* MSGL_DBG2 */
  };
  
  static void ass_log(int ass_level, const char *fmt, va_list args, void *ctx)
  {
      const int ass_level_clip = av_clip(ass_level, 0,
          FF_ARRAY_ELEMS(ass_libavfilter_log_level_map) - 1);
      const int level = ass_libavfilter_log_level_map[ass_level_clip];
  
      av_vlog(ctx, level, fmt, args);
      av_log(ctx, level, "\n");
  }
  
  static av_cold int init(AVFilterContext *ctx)
  {
      AssContext *ass = ctx->priv;
  
      if (!ass->filename) {
          av_log(ctx, AV_LOG_ERROR, "No filename provided!\n");
          return AVERROR(EINVAL);
      }
  
      ass->library = ass_library_init();
      if (!ass->library) {
          av_log(ctx, AV_LOG_ERROR, "Could not initialize libass.\n");
          return AVERROR(EINVAL);
      }
      ass_set_message_cb(ass->library, ass_log, ctx);
  
      ass_set_fonts_dir(ass->library, ass->fontsdir);
  
      ass->renderer = ass_renderer_init(ass->library);
      if (!ass->renderer) {
          av_log(ctx, AV_LOG_ERROR, "Could not initialize libass renderer.\n");
          return AVERROR(EINVAL);
      }
  
      return 0;
  }
  
  static av_cold void uninit(AVFilterContext *ctx)
  {
      AssContext *ass = ctx->priv;
  
      if (ass->track)
          ass_free_track(ass->track);
      if (ass->renderer)
          ass_renderer_done(ass->renderer);
      if (ass->library)
          ass_library_done(ass->library);
  }
  
  static int query_formats(AVFilterContext *ctx)
  {
      return ff_set_common_formats(ctx, ff_draw_supported_pixel_formats(0));
  }
  
  static int config_input(AVFilterLink *inlink)
  {
      AssContext *ass = inlink->dst->priv;
  
      ff_draw_init(&ass->draw, inlink->format, ass->alpha ? FF_DRAW_PROCESS_ALPHA : 0);
  
      ass_set_frame_size  (ass->renderer, inlink->w, inlink->h);
      if (ass->original_w && ass->original_h)
          ass_set_aspect_ratio(ass->renderer, (double)inlink->w / inlink->h,
                               (double)ass->original_w / ass->original_h);
      if (ass->shaping != -1)
          ass_set_shaper(ass->renderer, ass->shaping);
  
      return 0;
  }
  
  /* libass stores an RGBA color in the format RRGGBBTT, where TT is the transparency level */
  #define AR(c)  ( (c)>>24)
  #define AG(c)  (((c)>>16)&0xFF)
  #define AB(c)  (((c)>>8) &0xFF)
  #define AA(c)  ((0xFF-(c)) &0xFF)
  
  static void overlay_ass_image(AssContext *ass, AVFrame *picref,
                                const ASS_Image *image)
  {
      for (; image; image = image->next) {
          uint8_t rgba_color[] = {AR(image->color), AG(image->color), AB(image->color), AA(image->color)};
          FFDrawColor color;
          ff_draw_color(&ass->draw, &color, rgba_color);
          ff_blend_mask(&ass->draw, &color,
                        picref->data, picref->linesize,
                        picref->width, picref->height,
                        image->bitmap, image->stride, image->w, image->h,
                        3, 0, image->dst_x, image->dst_y);
      }
  }
  
  static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
  {
      AVFilterContext *ctx = inlink->dst;
      AVFilterLink *outlink = ctx->outputs[0];
      AssContext *ass = ctx->priv;
      int detect_change = 0;
      double time_ms = picref->pts * av_q2d(inlink->time_base) * 1000;
      ASS_Image *image = ass_render_frame(ass->renderer, ass->track,
                                          time_ms, &detect_change);
  
      if (detect_change)
          av_log(ctx, AV_LOG_DEBUG, "Change happened at time ms:%f\n", time_ms);
  
      overlay_ass_image(ass, picref, image);
  
      return ff_filter_frame(outlink, picref);
  }
  
  static const AVFilterPad ass_inputs[] = {
      {
          .name             = "default",
          .type             = AVMEDIA_TYPE_VIDEO,
          .filter_frame     = filter_frame,
          .config_props     = config_input,
          .needs_writable   = 1,
      },
      { NULL }
  };
  
  static const AVFilterPad ass_outputs[] = {
      {
          .name = "default",
          .type = AVMEDIA_TYPE_VIDEO,
      },
      { NULL }
  };
  
  #if CONFIG_ASS_FILTER
  
  static const AVOption ass_options[] = {
      COMMON_OPTIONS
      {"shaping", "set shaping engine", OFFSET(shaping), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 1, FLAGS, "shaping_mode"},
          {"auto", NULL,                 0, AV_OPT_TYPE_CONST, {.i64 = -1},                  INT_MIN, INT_MAX, FLAGS, "shaping_mode"},
          {"simple",  "simple shaping",  0, AV_OPT_TYPE_CONST, {.i64 = ASS_SHAPING_SIMPLE},  INT_MIN, INT_MAX, FLAGS, "shaping_mode"},
          {"complex", "complex shaping", 0, AV_OPT_TYPE_CONST, {.i64 = ASS_SHAPING_COMPLEX}, INT_MIN, INT_MAX, FLAGS, "shaping_mode"},
      {NULL},
  };
  
  AVFILTER_DEFINE_CLASS(ass);
  
  static av_cold int init_ass(AVFilterContext *ctx)
  {
      AssContext *ass = ctx->priv;
      int ret = init(ctx);
  
      if (ret < 0)
          return ret;
  
      /* Initialize fonts */
      ass_set_fonts(ass->renderer, NULL, NULL, 1, NULL, 1);
  
      ass->track = ass_read_file(ass->library, ass->filename, NULL);
      if (!ass->track) {
          av_log(ctx, AV_LOG_ERROR,
                 "Could not create a libass track when reading file '%s'\n",
                 ass->filename);
          return AVERROR(EINVAL);
      }
      return 0;
  }
  
  AVFilter ff_vf_ass = {
      .name          = "ass",
      .description   = NULL_IF_CONFIG_SMALL("Render ASS subtitles onto input video using the libass library."),
      .priv_size     = sizeof(AssContext),
      .init          = init_ass,
      .uninit        = uninit,
      .query_formats = query_formats,
      .inputs        = ass_inputs,
      .outputs       = ass_outputs,
      .priv_class    = &ass_class,
  };
  #endif
  
  #if CONFIG_SUBTITLES_FILTER
  
  static const AVOption subtitles_options[] = {
      COMMON_OPTIONS
      {"charenc",      "set input character encoding", OFFSET(charenc),      AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS},
      {"stream_index", "set stream index",             OFFSET(stream_index), AV_OPT_TYPE_INT,    { .i64 = -1 }, -1,       INT_MAX,  FLAGS},
      {"si",           "set stream index",             OFFSET(stream_index), AV_OPT_TYPE_INT,    { .i64 = -1 }, -1,       INT_MAX,  FLAGS},
      {"force_style",  "force subtitle style",         OFFSET(force_style),  AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS},
      {NULL},
  };
  
  static const char * const font_mimetypes[] = {
      "application/x-truetype-font",
      "application/vnd.ms-opentype",
      "application/x-font-ttf",
      NULL
  };
  
  static int attachment_is_font(AVStream * st)
  {
      const AVDictionaryEntry *tag = NULL;
      int n;
  
      tag = av_dict_get(st->metadata, "mimetype", NULL, AV_DICT_MATCH_CASE);
  
      if (tag) {
          for (n = 0; font_mimetypes[n]; n++) {
              if (av_strcasecmp(font_mimetypes[n], tag->value) == 0)
                  return 1;
          }
      }
      return 0;
  }
  
  AVFILTER_DEFINE_CLASS(subtitles);
  
  static av_cold int init_subtitles(AVFilterContext *ctx)
  {
      int j, ret, sid;
      int k = 0;
      AVDictionary *codec_opts = NULL;
      AVFormatContext *fmt = NULL;
      AVCodecContext *dec_ctx = NULL;
      AVCodec *dec = NULL;
      const AVCodecDescriptor *dec_desc;
      AVStream *st;
      AVPacket pkt;
      AssContext *ass = ctx->priv;
  
      /* Init libass */
      ret = init(ctx);
      if (ret < 0)
          return ret;
      ass->track = ass_new_track(ass->library);
      if (!ass->track) {
          av_log(ctx, AV_LOG_ERROR, "Could not create a libass track\n");
          return AVERROR(EINVAL);
      }
  
      /* Open subtitles file */
      ret = avformat_open_input(&fmt, ass->filename, NULL, NULL);
      if (ret < 0) {
          av_log(ctx, AV_LOG_ERROR, "Unable to open %s\n", ass->filename);
          goto end;
      }
      ret = avformat_find_stream_info(fmt, NULL);
      if (ret < 0)
          goto end;
  
      /* Locate subtitles stream */
      if (ass->stream_index < 0)
          ret = av_find_best_stream(fmt, AVMEDIA_TYPE_SUBTITLE, -1, -1, NULL, 0);
      else {
          ret = -1;
          if (ass->stream_index < fmt->nb_streams) {
              for (j = 0; j < fmt->nb_streams; j++) {
                  if (fmt->streams[j]->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE) {
                      if (ass->stream_index == k) {
                          ret = j;
                          break;
                      }
                      k++;
                  }
              }
          }
      }
  
      if (ret < 0) {
          av_log(ctx, AV_LOG_ERROR, "Unable to locate subtitle stream in %s\n",
                 ass->filename);
          goto end;
      }
      sid = ret;
      st = fmt->streams[sid];
  
      /* Load attached fonts */
      for (j = 0; j < fmt->nb_streams; j++) {
          AVStream *st = fmt->streams[j];
          if (st->codecpar->codec_type == AVMEDIA_TYPE_ATTACHMENT &&
              attachment_is_font(st)) {
              const AVDictionaryEntry *tag = NULL;
              tag = av_dict_get(st->metadata, "filename", NULL,
                                AV_DICT_MATCH_CASE);
  
              if (tag) {
                  av_log(ctx, AV_LOG_DEBUG, "Loading attached font: %s\n",
                         tag->value);
                  ass_add_font(ass->library, tag->value,
                               st->codecpar->extradata,
                               st->codecpar->extradata_size);
              } else {
                  av_log(ctx, AV_LOG_WARNING,
                         "Font attachment has no filename, ignored.\n");
              }
          }
      }
  
      /* Initialize fonts */
      ass_set_fonts(ass->renderer, NULL, NULL, 1, NULL, 1);
  
      /* Open decoder */
      dec = avcodec_find_decoder(st->codecpar->codec_id);
      if (!dec) {
          av_log(ctx, AV_LOG_ERROR, "Failed to find subtitle codec %s\n",
                 avcodec_get_name(st->codecpar->codec_id));
          return AVERROR(EINVAL);
      }
      dec_desc = avcodec_descriptor_get(st->codecpar->codec_id);
      if (dec_desc && !(dec_desc->props & AV_CODEC_PROP_TEXT_SUB)) {
          av_log(ctx, AV_LOG_ERROR,
                 "Only text based subtitles are currently supported\n");
          return AVERROR_PATCHWELCOME;
      }
      if (ass->charenc)
          av_dict_set(&codec_opts, "sub_charenc", ass->charenc, 0);
      if (LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(57,26,100))
          av_dict_set(&codec_opts, "sub_text_format", "ass", 0);
  
      dec_ctx = avcodec_alloc_context3(dec);
      if (!dec_ctx)
          return AVERROR(ENOMEM);
  
      ret = avcodec_parameters_to_context(dec_ctx, st->codecpar);
      if (ret < 0)
          goto end;
  
      /*
       * This is required by the decoding process in order to rescale the
       * timestamps: in the current API the decoded subtitles have their pts
       * expressed in AV_TIME_BASE, and thus the lavc internals need to know the
       * stream time base in order to achieve the rescaling.
       *
       * That API is old and needs to be reworked to match behaviour with A/V.
       */
      av_codec_set_pkt_timebase(dec_ctx, st->time_base);
  
      ret = avcodec_open2(dec_ctx, NULL, &codec_opts);
      if (ret < 0)
          goto end;
  
      if (ass->force_style) {
          char **list = NULL;
          char *temp = NULL;
          char *ptr = av_strtok(ass->force_style, ",", &temp);
          int i = 0;
          while (ptr) {
              av_dynarray_add(&list, &i, ptr);
              if (!list) {
                  ret = AVERROR(ENOMEM);
                  goto end;
              }
              ptr = av_strtok(NULL, ",", &temp);
          }
          av_dynarray_add(&list, &i, NULL);
          if (!list) {
              ret = AVERROR(ENOMEM);
              goto end;
          }
          ass_set_style_overrides(ass->library, list);
          av_free(list);
      }
      /* Decode subtitles and push them into the renderer (libass) */
      if (dec_ctx->subtitle_header)
          ass_process_codec_private(ass->track,
                                    dec_ctx->subtitle_header,
                                    dec_ctx->subtitle_header_size);
      av_init_packet(&pkt);
      pkt.data = NULL;
      pkt.size = 0;
      while (av_read_frame(fmt, &pkt) >= 0) {
          int i, got_subtitle;
          AVSubtitle sub = {0};
  
          if (pkt.stream_index == sid) {
              ret = avcodec_decode_subtitle2(dec_ctx, &sub, &got_subtitle, &pkt);
              if (ret < 0) {
                  av_log(ctx, AV_LOG_WARNING, "Error decoding: %s (ignored)\n",
                         av_err2str(ret));
              } else if (got_subtitle) {
                  const int64_t start_time = av_rescale_q(sub.pts, AV_TIME_BASE_Q, av_make_q(1, 1000));
                  const int64_t duration   = sub.end_display_time;
                  for (i = 0; i < sub.num_rects; i++) {
                      char *ass_line = sub.rects[i]->ass;
                      if (!ass_line)
                          break;
                      if (LIBAVCODEC_VERSION_INT < AV_VERSION_INT(57,25,100))
                          ass_process_data(ass->track, ass_line, strlen(ass_line));
                      else
                          ass_process_chunk(ass->track, ass_line, strlen(ass_line),
                                            start_time, duration);
                  }
              }
          }
          av_packet_unref(&pkt);
          avsubtitle_free(&sub);
      }
  
  end:
      av_dict_free(&codec_opts);
      avcodec_close(dec_ctx);
      avcodec_free_context(&dec_ctx);
      avformat_close_input(&fmt);
      return ret;
  }
  
  AVFilter ff_vf_subtitles = {
      .name          = "subtitles",
      .description   = NULL_IF_CONFIG_SMALL("Render text subtitles onto input video using the libass library."),
      .priv_size     = sizeof(AssContext),
      .init          = init_subtitles,
      .uninit        = uninit,
      .query_formats = query_formats,
      .inputs        = ass_inputs,
      .outputs       = ass_outputs,
      .priv_class    = &subtitles_class,
  };
  #endif
  