libavformat/samidec.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  * SAMI subtitle demuxer
  24  * @see http://msdn.microsoft.com/en-us/library/ms971327.aspx
  25  */
  26
  27 #include "avformat.h"
  28 #include "demux.h"
  29 #include "internal.h"
  30 #include "subtitles.h"
  31 #include "libavutil/avstring.h"
  32 #include "libavutil/bprint.h"
  33
  34 typedef struct {
  35     FFDemuxSubtitlesQueue q;
  36 } SAMIContext;
  37
  38 static int sami_probe(const AVProbeData *p)
  39 {
  40     char buf[6];
  41     FFTextReader tr;
  42     ff_text_init_buf(&tr, p->buf, p->buf_size);
  43     ff_text_read(&tr, buf, sizeof(buf));
  44
  45     return !strncmp(buf, "<SAMI>", 6) ? AVPROBE_SCORE_MAX : 0;
  46 }
  47
  48 static int sami_read_header(AVFormatContext *s)
  49 {
  50     SAMIContext *sami = s->priv_data;
  51     AVStream *st = avformat_new_stream(s, NULL);
  52     AVBPrint buf, hdr_buf;
  53     char c = 0;
  54     int res = 0, got_first_sync_point = 0;
  55     FFTextReader tr;
  56     ff_text_init_avio(s, &tr, s->pb);
  57
  58     if (!st)
  59         return AVERROR(ENOMEM);
  60     avpriv_set_pts_info(st, 64, 1, 1000);
  61     st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
  62     st->codecpar->codec_id   = AV_CODEC_ID_SAMI;
  63
  64     av_bprint_init(&buf,     0, AV_BPRINT_SIZE_UNLIMITED);
  65     av_bprint_init(&hdr_buf, 0, AV_BPRINT_SIZE_UNLIMITED);
  66
  67     while (!ff_text_eof(&tr)) {
  68         AVPacket *sub;
  69         const int64_t pos = ff_text_pos(&tr) - (c != 0);
  70         int is_sync, is_body, n = ff_smil_extract_next_text_chunk(&tr, &buf, &c);
  71
  72         if (n < 0) {
  73             res = n;
  74             goto end;
  75         }
  76         if (n == 0)
  77             break;
  78
  79         is_body = !av_strncasecmp(buf.str, "</BODY", 6);
  80         if (is_body) {
  81              av_bprint_clear(&buf);
  82              break;
  83         }
  84
  85         is_sync = !av_strncasecmp(buf.str, "<SYNC", 5);
  86         if (is_sync)
  87             got_first_sync_point = 1;
  88
  89         if (!got_first_sync_point) {
  90             av_bprintf(&hdr_buf, "%s", buf.str);
  91         } else {
  92             sub = ff_subtitles_queue_insert_bprint(&sami->q, &buf, !is_sync);
  93             if (!sub) {
  94                 res = AVERROR(ENOMEM);
  95                 av_bprint_finalize(&hdr_buf, NULL);
  96                 goto end;
  97             }
  98             if (is_sync) {
  99                 const char *p = ff_smil_get_attr_ptr(buf.str, "Start");
 100                 sub->pos      = pos;
 101                 sub->pts      = p ? strtol(p, NULL, 10) : 0;
 102                 if (sub->pts <= INT64_MIN/2 || sub->pts >= INT64_MAX/2) {
 103                     res = AVERROR_PATCHWELCOME;
 104                     av_bprint_finalize(&hdr_buf, NULL);
 105                     goto end;
 106                 }
 107
 108                 sub->duration = -1;
 109             }
 110         }
 111         av_bprint_clear(&buf);
 112     }
 113
 114     res = ff_bprint_to_codecpar_extradata(st->codecpar, &hdr_buf);
 115     if (res < 0)
 116         goto end;
 117
 118     ff_subtitles_queue_finalize(s, &sami->q);
 119
 120 end:
 121     av_bprint_finalize(&buf, NULL);
 122     return res;
 123 }
 124
 125 const FFInputFormat ff_sami_demuxer = {
 126     .p.name         = "sami",
 127     .p.long_name    = NULL_IF_CONFIG_SMALL("SAMI subtitle format"),
 128     .p.extensions   = "smi,sami",
 129     .priv_data_size = sizeof(SAMIContext),
 130     .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,
 131     .read_probe     = sami_probe,
 132     .read_header    = sami_read_header,
 133     .read_packet    = ff_subtitles_read_packet,
 134     .read_seek2     = ff_subtitles_read_seek,
 135     .read_close     = ff_subtitles_read_close,
 136 };