libavformat/subviewerdec.c

   1 /*
   2  * Copyright (c) 2012 Clément Bœsch
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file
  23  * SubViewer subtitle demuxer
  24  * @see https://en.wikipedia.org/wiki/SubViewer
  25  */
  26
  27 #include "avformat.h"
  28 #include "demux.h"
  29 #include "internal.h"
  30 #include "subtitles.h"
  31 #include "avio_internal.h"
  32 #include "libavutil/avstring.h"
  33 #include "libavutil/bprint.h"
  34 #include "libavutil/intreadwrite.h"
  35
  36 typedef struct {
  37     FFDemuxSubtitlesQueue q;
  38 } SubViewerContext;
  39
  40 static int subviewer_probe(const AVProbeData *p)
  41 {
  42     char c;
  43     const unsigned char *ptr = p->buf;
  44
  45     if (AV_RB24(ptr) == 0xEFBBBF)
  46         ptr += 3;  /* skip UTF-8 BOM */
  47     if (sscanf(ptr, "%*u:%*u:%*u.%*u,%*u:%*u:%*u.%*u%c", &c) == 1)
  48         return AVPROBE_SCORE_EXTENSION;
  49     if (!strncmp(ptr, "[INFORMATION]", 13))
  50         return AVPROBE_SCORE_MAX/3;
  51     return 0;
  52 }
  53
  54 static int get_multiplier(int e) {
  55     switch (e) {
  56     case 1  : return 100;
  57     case 2  : return 10;
  58     case 3  : return 1;
  59     default : return -1;
  60     }
  61 }
  62
  63 static int read_ts(const char *s, int64_t *start, int *duration)
  64 {
  65     int64_t end;
  66     int hh1, mm1, ss1, ms1;
  67     int hh2, mm2, ss2, ms2;
  68     int multiplier1, multiplier2;
  69     int ms1p1, ms1p2, ms2p1, ms2p2;
  70
  71     if (sscanf(s, "%u:%u:%u.%n%u%n,%u:%u:%u.%n%u%n",
  72                &hh1, &mm1, &ss1, &ms1p1, &ms1, &ms1p2, &hh2, &mm2, &ss2, &ms2p1, &ms2, &ms2p2) == 8) {
  73         multiplier1 = get_multiplier(ms1p2 - ms1p1);
  74         multiplier2 = get_multiplier(ms2p2 - ms2p1);
  75         if (multiplier1 <= 0 ||multiplier2 <= 0)
  76             return -1;
  77
  78         end    = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2 * multiplier2;
  79         *start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1 * multiplier1;
  80         *duration = end - *start;
  81         return 0;
  82     }
  83     return -1;
  84 }
  85
  86 static int subviewer_read_header(AVFormatContext *s)
  87 {
  88     SubViewerContext *subviewer = s->priv_data;
  89     AVStream *st = avformat_new_stream(s, NULL);
  90     AVBPrint header;
  91     int res = 0, new_event = 1;
  92     int64_t pts_start = AV_NOPTS_VALUE;
  93     int duration = -1;
  94     AVPacket *sub = NULL;
  95
  96     if (!st)
  97         return AVERROR(ENOMEM);
  98     res = ffio_ensure_seekback(s->pb, 3);
  99     if (res < 0)
 100         return res;
 101     if (avio_rb24(s->pb) != 0xefbbbf)
 102         avio_seek(s->pb, -3, SEEK_CUR);
 103     avpriv_set_pts_info(st, 64, 1, 1000);
 104     st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
 105     st->codecpar->codec_id   = AV_CODEC_ID_SUBVIEWER;
 106
 107     av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
 108
 109     while (!avio_feof(s->pb)) {
 110         char line[2048];
 111         int64_t pos = 0;
 112         int len = ff_get_line(s->pb, line, sizeof(line));
 113
 114         if (!len)
 115             break;
 116
 117         line[strcspn(line, "\r\n")] = 0;
 118
 119         if (line[0] == '[' && strncmp(line, "[br]", 4)) {
 120
 121             /* ignore event style, XXX: add to side_data? */
 122             if (strstr(line, "[COLF]") || strstr(line, "[SIZE]") ||
 123                 strstr(line, "[FONT]") || strstr(line, "[STYLE]"))
 124                 continue;
 125
 126             if (!st->codecpar->extradata) { // header not finalized yet
 127                 av_bprintf(&header, "%s\n", line);
 128                 if (!strncmp(line, "[END INFORMATION]", 17) || !strncmp(line, "[SUBTITLE]", 10)) {
 129                     /* end of header */
 130                     res = ff_bprint_to_codecpar_extradata(st->codecpar, &header);
 131                     if (res < 0)
 132                         goto end;
 133                 } else if (strncmp(line, "[INFORMATION]", 13)) {
 134                     /* assume file metadata at this point */
 135                     int i, j = 0;
 136                     char key[32], value[128];
 137
 138                     for (i = 1; i < sizeof(key) - 1 && line[i] && line[i] != ']'; i++)
 139                         key[i - 1] = av_tolower(line[i]);
 140                     key[i - 1] = 0;
 141
 142                     if (line[i] == ']')
 143                         i++;
 144                     while (line[i] == ' ')
 145                         i++;
 146                     while (j < sizeof(value) - 1 && line[i] && line[i] != ']')
 147                         value[j++] = line[i++];
 148                     value[j] = 0;
 149
 150                     av_dict_set(&s->metadata, key, value, 0);
 151                 }
 152             }
 153         } else if (read_ts(line, &pts_start, &duration) >= 0) {
 154             new_event = 1;
 155             pos = avio_tell(s->pb);
 156         } else if (*line) {
 157             if (pts_start == AV_NOPTS_VALUE) {
 158                 res = AVERROR_INVALIDDATA;
 159                 goto end;
 160             }
 161             if (!new_event) {
 162                 sub = ff_subtitles_queue_insert(&subviewer->q, "\n", 1, 1);
 163                 if (!sub) {
 164                     res = AVERROR(ENOMEM);
 165                     goto end;
 166                 }
 167             }
 168             sub = ff_subtitles_queue_insert(&subviewer->q, line, strlen(line), !new_event);
 169             if (!sub) {
 170                 res = AVERROR(ENOMEM);
 171                 goto end;
 172             }
 173             if (new_event) {
 174                 sub->pos = pos;
 175                 sub->pts = pts_start;
 176                 sub->duration = duration;
 177             }
 178             new_event = 0;
 179         }
 180     }
 181
 182     ff_subtitles_queue_finalize(s, &subviewer->q);
 183
 184 end:
 185     av_bprint_finalize(&header, NULL);
 186     return res;
 187 }
 188
 189 const FFInputFormat ff_subviewer_demuxer = {
 190     .p.name         = "subviewer",
 191     .p.long_name    = NULL_IF_CONFIG_SMALL("SubViewer subtitle format"),
 192     .p.extensions   = "sub",
 193     .priv_data_size = sizeof(SubViewerContext),
 194     .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,
 195     .read_probe     = subviewer_probe,
 196     .read_header    = subviewer_read_header,
 197     .read_packet    = ff_subtitles_read_packet,
 198     .read_seek2     = ff_subtitles_read_seek,
 199     .read_close     = ff_subtitles_read_close,
 200 };