ffmpeg/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 "internal.h"
  29 #include "subtitles.h"
  30 #include "libavcodec/internal.h"
  31 #include "libavutil/avstring.h"
  32 #include "libavutil/bprint.h"
  33 #include "libavutil/intreadwrite.h"
  34
  35 typedef struct {
  36     FFDemuxSubtitlesQueue q;
  37 } SAMIContext;
  38
  39 static int sami_probe(AVProbeData *p)
  40 {
  41     char buf[6];
  42     FFTextReader tr;
  43     ff_text_init_buf(&tr, p->buf, p->buf_size);
  44     ff_text_read(&tr, buf, sizeof(buf));
  45
  46     return !strncmp(buf, "<SAMI>", 6) ? AVPROBE_SCORE_MAX : 0;
  47 }
  48
  49 static int sami_read_header(AVFormatContext *s)
  50 {
  51     SAMIContext *sami = s->priv_data;
  52     AVStream *st = avformat_new_stream(s, NULL);
  53     AVBPrint buf, hdr_buf;
  54     char c = 0;
  55     int res = 0, got_first_sync_point = 0;
  56     FFTextReader tr;
  57     ff_text_init_avio(s, &tr, s->pb);
  58
  59     if (!st)
  60         return AVERROR(ENOMEM);
  61     avpriv_set_pts_info(st, 64, 1, 1000);
  62     st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
  63     st->codec->codec_id   = AV_CODEC_ID_SAMI;
  64
  65     av_bprint_init(&buf,     0, AV_BPRINT_SIZE_UNLIMITED);
  66     av_bprint_init(&hdr_buf, 0, AV_BPRINT_SIZE_UNLIMITED);
  67
  68     while (!ff_text_eof(&tr)) {
  69         AVPacket *sub;
  70         const int64_t pos = ff_text_pos(&tr) - (c != 0);
  71         int is_sync, n = ff_smil_extract_next_text_chunk(&tr, &buf, &c);
  72
  73         if (n == 0)
  74             break;
  75
  76         is_sync = !av_strncasecmp(buf.str, "<SYNC", 5);
  77         if (is_sync)
  78             got_first_sync_point = 1;
  79
  80         if (!got_first_sync_point) {
  81             av_bprintf(&hdr_buf, "%s", buf.str);
  82         } else {
  83             sub = ff_subtitles_queue_insert(&sami->q, buf.str, buf.len, !is_sync);
  84             if (!sub) {
  85                 res = AVERROR(ENOMEM);
  86                 goto end;
  87             }
  88             if (is_sync) {
  89                 const char *p = ff_smil_get_attr_ptr(buf.str, "Start");
  90                 sub->pos      = pos;
  91                 sub->pts      = p ? strtol(p, NULL, 10) : 0;
  92                 sub->duration = -1;
  93             }
  94         }
  95         av_bprint_clear(&buf);
  96     }
  97
  98     res = avpriv_bprint_to_extradata(st->codec, &hdr_buf);
  99     if (res < 0)
 100         goto end;
 101
 102     ff_subtitles_queue_finalize(&sami->q);
 103
 104 end:
 105     av_bprint_finalize(&buf, NULL);
 106     return res;
 107 }
 108
 109 static int sami_read_packet(AVFormatContext *s, AVPacket *pkt)
 110 {
 111     SAMIContext *sami = s->priv_data;
 112     return ff_subtitles_queue_read_packet(&sami->q, pkt);
 113 }
 114
 115 static int sami_read_seek(AVFormatContext *s, int stream_index,
 116                           int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
 117 {
 118     SAMIContext *sami = s->priv_data;
 119     return ff_subtitles_queue_seek(&sami->q, s, stream_index,
 120                                    min_ts, ts, max_ts, flags);
 121 }
 122
 123 static int sami_read_close(AVFormatContext *s)
 124 {
 125     SAMIContext *sami = s->priv_data;
 126     ff_subtitles_queue_clean(&sami->q);
 127     return 0;
 128 }
 129
 130 AVInputFormat ff_sami_demuxer = {
 131     .name           = "sami",
 132     .long_name      = NULL_IF_CONFIG_SMALL("SAMI subtitle format"),
 133     .priv_data_size = sizeof(SAMIContext),
 134     .read_probe     = sami_probe,
 135     .read_header    = sami_read_header,
 136     .read_packet    = sami_read_packet,
 137     .read_seek2     = sami_read_seek,
 138     .read_close     = sami_read_close,
 139     .extensions     = "smi,sami",
 140 };