libavcodec/realtextdec.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  * RealText subtitle decoder
  24  * @see http://service.real.com/help/library/guides/ProductionGuide/prodguide/htmfiles/realtext.htm
  25  */
  26
  27 #include "avcodec.h"
  28 #include "ass.h"
  29 #include "codec_internal.h"
  30 #include "libavutil/avstring.h"
  31 #include "libavutil/bprint.h"
  32
  33 static int rt_event_to_ass(AVBPrint *buf, const char *p)
  34 {
  35     int prev_chr_is_space = 1;
  36
  37     while (*p) {
  38         if (*p != '<') {
  39             if (!av_isspace(*p))
  40                 av_bprint_chars(buf, *p, 1);
  41             else if (!prev_chr_is_space)
  42                 av_bprint_chars(buf, ' ', 1);
  43             prev_chr_is_space = av_isspace(*p);
  44         } else {
  45             const char *end = strchr(p, '>');
  46             if (!end)
  47                 break;
  48             if (!av_strncasecmp(p, "<br/>", 5) ||
  49                 !av_strncasecmp(p, "<br>",  4)) {
  50                 av_bprintf(buf, "\\N");
  51             }
  52             p = end;
  53         }
  54         p++;
  55     }
  56     return 0;
  57 }
  58
  59 static int realtext_decode_frame(AVCodecContext *avctx, AVSubtitle *sub,
  60                                  int *got_sub_ptr, const AVPacket *avpkt)
  61 {
  62     int ret = 0;
  63     const char *ptr = avpkt->data;
  64     FFASSDecoderContext *s = avctx->priv_data;
  65     AVBPrint buf;
  66
  67     av_bprint_init(&buf, 0, 4096);
  68     if (ptr && avpkt->size > 0 && !rt_event_to_ass(&buf, ptr))
  69         ret = ff_ass_add_rect(sub, buf.str, s->readorder++, 0, NULL, NULL);
  70     av_bprint_finalize(&buf, NULL);
  71     if (ret < 0)
  72         return ret;
  73     *got_sub_ptr = sub->num_rects > 0;
  74     return avpkt->size;
  75 }
  76
  77 const FFCodec ff_realtext_decoder = {
  78     .p.name         = "realtext",
  79     CODEC_LONG_NAME("RealText subtitle"),
  80     .p.type         = AVMEDIA_TYPE_SUBTITLE,
  81     .p.id           = AV_CODEC_ID_REALTEXT,
  82     FF_CODEC_DECODE_SUB_CB(realtext_decode_frame),
  83     .init           = ff_ass_subtitle_header_default,
  84     .flush          = ff_ass_decoder_flush,
  85     .priv_data_size = sizeof(FFASSDecoderContext),
  86 };