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  1. /*
  2.  * This file is part of FFmpeg.
  3.  *
  4.  * FFmpeg is free software; you can redistribute it and/or
  5.  * modify it under the terms of the GNU Lesser General Public
  6.  * License as published by the Free Software Foundation; either
  7.  * version 2.1 of the License, or (at your option) any later version.
  8.  *
  9.  * FFmpeg is distributed in the hope that it will be useful,
  10.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12.  * Lesser General Public License for more details.
  13.  *
  14.  * You should have received a copy of the GNU Lesser General Public
  15.  * License along with FFmpeg; if not, write to the Free Software
  16.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17.  */
  18.  
  19. #include "avformat.h"
  20. #include "internal.h"
  21. #include "libavutil/intreadwrite.h"
  22.  
  23. #define SUP_PGS_MAGIC 0x5047 /* "PG", big endian */
  24.  
  25. static int sup_read_header(AVFormatContext *s)
  26. {
  27.     AVStream *st = avformat_new_stream(s, NULL);
  28.     if (!st)
  29.         return AVERROR(ENOMEM);
  30.     st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
  31.     st->codec->codec_id = AV_CODEC_ID_HDMV_PGS_SUBTITLE;
  32.     avpriv_set_pts_info(st, 32, 1, 90000);
  33.  
  34.     return 0;
  35. }
  36.  
  37. static int sup_read_packet(AVFormatContext *s, AVPacket *pkt)
  38. {
  39.     int64_t pts, dts, pos;
  40.     int ret;
  41.  
  42.     pos = avio_tell(s->pb);
  43.  
  44.     if (avio_rb16(s->pb) != SUP_PGS_MAGIC)
  45.         return avio_feof(s->pb) ? AVERROR_EOF : AVERROR_INVALIDDATA;
  46.  
  47.     pts = avio_rb32(s->pb);
  48.     dts = avio_rb32(s->pb);
  49.  
  50.     if ((ret = av_get_packet(s->pb, pkt, 3)) < 0)
  51.         return ret;
  52.  
  53.     pkt->stream_index = 0;
  54.     pkt->flags |= AV_PKT_FLAG_KEY;
  55.     pkt->pos = pos;
  56.     pkt->pts = pts;
  57.     // Many files have DTS set to 0 for all packets, so assume 0 means unset.
  58.     pkt->dts = dts ? dts : AV_NOPTS_VALUE;
  59.  
  60.     if (pkt->size >= 3) {
  61.         // The full packet size is stored as part of the packet.
  62.         size_t len = AV_RB16(pkt->data + 1);
  63.  
  64.         if ((ret = av_append_packet(s->pb, pkt, len)) < 0)
  65.             return ret;
  66.     }
  67.  
  68.     return 0;
  69. }
  70.  
  71. static int sup_probe(AVProbeData *p)
  72. {
  73.     unsigned char *buf = p->buf;
  74.     size_t buf_size = p->buf_size;
  75.     int nb_packets;
  76.  
  77.     for (nb_packets = 0; nb_packets < 10; nb_packets++) {
  78.         size_t full_packet_size;
  79.         if (buf_size < 10 + 3)
  80.             break;
  81.         if (AV_RB16(buf) != SUP_PGS_MAGIC)
  82.             return 0;
  83.         full_packet_size = AV_RB16(buf + 10 + 1) + 10 + 3;
  84.         if (buf_size < full_packet_size)
  85.             break;
  86.         buf += full_packet_size;
  87.         buf_size -= full_packet_size;
  88.     }
  89.     if (!nb_packets)
  90.         return 0;
  91.     if (nb_packets < 2)
  92.         return AVPROBE_SCORE_RETRY / 2;
  93.     if (nb_packets < 4)
  94.         return AVPROBE_SCORE_RETRY;
  95.     if (nb_packets < 10)
  96.         return AVPROBE_SCORE_EXTENSION;
  97.     return AVPROBE_SCORE_MAX;
  98. }
  99.  
  100. AVInputFormat ff_sup_demuxer = {
  101.     .name           = "sup",
  102.     .long_name      = NULL_IF_CONFIG_SMALL("raw HDMV Presentation Graphic Stream subtitles"),
  103.     .extensions     = "sup",
  104.     .mime_type      = "application/x-pgs",
  105.     .read_probe     = sup_probe,
  106.     .read_header    = sup_read_header,
  107.     .read_packet    = sup_read_packet,
  108.     .flags          = AVFMT_GENERIC_INDEX,
  109. };
  110.