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  1. /*
  2.  * SubRip subtitle demuxer
  3.  * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. #include "avformat.h"
  23. #include "internal.h"
  24. #include "subtitles.h"
  25. #include "libavutil/bprint.h"
  26. #include "libavutil/intreadwrite.h"
  27.  
  28. typedef struct {
  29.     FFDemuxSubtitlesQueue q;
  30. } SRTContext;
  31.  
  32. static int srt_probe(AVProbeData *p)
  33. {
  34.     const unsigned char *ptr = p->buf;
  35.     int i, v, num = 0;
  36.  
  37.     if (AV_RB24(ptr) == 0xEFBBBF)
  38.         ptr += 3;  /* skip UTF-8 BOM */
  39.  
  40.     while (*ptr == '\r' || *ptr == '\n')
  41.         ptr++;
  42.     for (i=0; i<2; i++) {
  43.         if ((num == i || num + 1 == i)
  44.             && sscanf(ptr, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
  45.             return AVPROBE_SCORE_MAX;
  46.         num = atoi(ptr);
  47.         ptr += ff_subtitles_next_line(ptr);
  48.     }
  49.     return 0;
  50. }
  51.  
  52. static int64_t get_pts(const char **buf, int *duration,
  53.                        int32_t *x1, int32_t *y1, int32_t *x2, int32_t *y2)
  54. {
  55.     int i;
  56.  
  57.     for (i=0; i<2; i++) {
  58.         int hh1, mm1, ss1, ms1;
  59.         int hh2, mm2, ss2, ms2;
  60.         if (sscanf(*buf, "%d:%2d:%2d%*1[,.]%3d --> %d:%2d:%2d%*1[,.]%3d"
  61.                    "%*[ ]X1:%u X2:%u Y1:%u Y2:%u",
  62.                    &hh1, &mm1, &ss1, &ms1,
  63.                    &hh2, &mm2, &ss2, &ms2,
  64.                    x1, x2, y1, y2) >= 8) {
  65.             int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
  66.             int64_t end   = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
  67.             *duration = end - start;
  68.             *buf += ff_subtitles_next_line(*buf);
  69.             return start;
  70.         }
  71.         *buf += ff_subtitles_next_line(*buf);
  72.     }
  73.     return AV_NOPTS_VALUE;
  74. }
  75.  
  76. static int srt_read_header(AVFormatContext *s)
  77. {
  78.     SRTContext *srt = s->priv_data;
  79.     AVBPrint buf;
  80.     AVStream *st = avformat_new_stream(s, NULL);
  81.     int res = 0;
  82.  
  83.     if (!st)
  84.         return AVERROR(ENOMEM);
  85.     avpriv_set_pts_info(st, 64, 1, 1000);
  86.     st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
  87.     st->codec->codec_id   = AV_CODEC_ID_SUBRIP;
  88.  
  89.     av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
  90.  
  91.     while (!url_feof(s->pb)) {
  92.         ff_subtitles_read_chunk(s->pb, &buf);
  93.  
  94.         if (buf.len) {
  95.             int64_t pos = avio_tell(s->pb);
  96.             int64_t pts;
  97.             int duration;
  98.             const char *ptr = buf.str;
  99.             int32_t x1 = -1, y1 = -1, x2 = -1, y2 = -1;
  100.             AVPacket *sub;
  101.  
  102.             pts = get_pts(&ptr, &duration, &x1, &y1, &x2, &y2);
  103.             if (pts != AV_NOPTS_VALUE) {
  104.                 int len = buf.len - (ptr - buf.str);
  105.                 if (len <= 0)
  106.                     continue;
  107.                 sub = ff_subtitles_queue_insert(&srt->q, ptr, len, 0);
  108.                 if (!sub) {
  109.                     res = AVERROR(ENOMEM);
  110.                     goto end;
  111.                 }
  112.                 sub->pos = pos;
  113.                 sub->pts = pts;
  114.                 sub->duration = duration;
  115.                 if (x1 != -1) {
  116.                     uint8_t *p = av_packet_new_side_data(sub, AV_PKT_DATA_SUBTITLE_POSITION, 16);
  117.                     if (p) {
  118.                         AV_WL32(p,      x1);
  119.                         AV_WL32(p +  4, y1);
  120.                         AV_WL32(p +  8, x2);
  121.                         AV_WL32(p + 12, y2);
  122.                     }
  123.                 }
  124.             }
  125.         }
  126.     }
  127.  
  128.     ff_subtitles_queue_finalize(&srt->q);
  129.  
  130. end:
  131.     av_bprint_finalize(&buf, NULL);
  132.     return res;
  133. }
  134.  
  135. static int srt_read_packet(AVFormatContext *s, AVPacket *pkt)
  136. {
  137.     SRTContext *srt = s->priv_data;
  138.     return ff_subtitles_queue_read_packet(&srt->q, pkt);
  139. }
  140.  
  141. static int srt_read_seek(AVFormatContext *s, int stream_index,
  142.                          int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
  143. {
  144.     SRTContext *srt = s->priv_data;
  145.     return ff_subtitles_queue_seek(&srt->q, s, stream_index,
  146.                                    min_ts, ts, max_ts, flags);
  147. }
  148.  
  149. static int srt_read_close(AVFormatContext *s)
  150. {
  151.     SRTContext *srt = s->priv_data;
  152.     ff_subtitles_queue_clean(&srt->q);
  153.     return 0;
  154. }
  155.  
  156. AVInputFormat ff_srt_demuxer = {
  157.     .name        = "srt",
  158.     .long_name   = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
  159.     .priv_data_size = sizeof(SRTContext),
  160.     .read_probe  = srt_probe,
  161.     .read_header = srt_read_header,
  162.     .read_packet = srt_read_packet,
  163.     .read_seek2  = srt_read_seek,
  164.     .read_close  = srt_read_close,
  165. };
  166.