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  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 decoder
  24.  * @see http://msdn.microsoft.com/en-us/library/ms971327.aspx
  25.  */
  26.  
  27. #include "ass.h"
  28. #include "libavutil/avstring.h"
  29. #include "libavutil/bprint.h"
  30.  
  31. typedef struct {
  32.     AVBPrint source;
  33.     AVBPrint content;
  34.     AVBPrint full;
  35. } SAMIContext;
  36.  
  37. static int sami_paragraph_to_ass(AVCodecContext *avctx, const char *src)
  38. {
  39.     SAMIContext *sami = avctx->priv_data;
  40.     int ret = 0;
  41.     char *tag = NULL;
  42.     char *dupsrc = av_strdup(src);
  43.     char *p = dupsrc;
  44.  
  45.     av_bprint_clear(&sami->content);
  46.     for (;;) {
  47.         char *saveptr = NULL;
  48.         int prev_chr_is_space = 0;
  49.         AVBPrint *dst = &sami->content;
  50.  
  51.         /* parse & extract paragraph tag */
  52.         p = av_stristr(p, "<P");
  53.         if (!p)
  54.             break;
  55.         if (p[2] != '>' && !av_isspace(p[2])) { // avoid confusion with tags such as <PRE>
  56.             p++;
  57.             continue;
  58.         }
  59.         if (dst->len) // add a separator with the previous paragraph if there was one
  60.             av_bprintf(dst, "\\N");
  61.         tag = av_strtok(p, ">", &saveptr);
  62.         if (!tag || !saveptr)
  63.             break;
  64.         p = saveptr;
  65.  
  66.         /* check if the current paragraph is the "source" (speaker name) */
  67.         if (av_stristr(tag, "ID=Source") || av_stristr(tag, "ID=\"Source\"")) {
  68.             dst = &sami->source;
  69.             av_bprint_clear(dst);
  70.         }
  71.  
  72.         /* if empty event -> skip subtitle */
  73.         while (av_isspace(*p))
  74.             p++;
  75.         if (!strncmp(p, "&nbsp;", 6)) {
  76.             ret = -1;
  77.             goto end;
  78.         }
  79.  
  80.         /* extract the text, stripping most of the tags */
  81.         while (*p) {
  82.             if (*p == '<') {
  83.                 if (!av_strncasecmp(p, "<P", 2) && (p[2] == '>' || av_isspace(p[2])))
  84.                     break;
  85.                 if (!av_strncasecmp(p, "<BR", 3))
  86.                     av_bprintf(dst, "\\N");
  87.                 p++;
  88.                 while (*p && *p != '>')
  89.                     p++;
  90.                 if (!*p)
  91.                     break;
  92.                 if (*p == '>')
  93.                     p++;
  94.             }
  95.             if (!av_isspace(*p))
  96.                 av_bprint_chars(dst, *p, 1);
  97.             else if (!prev_chr_is_space)
  98.                 av_bprint_chars(dst, ' ', 1);
  99.             prev_chr_is_space = av_isspace(*p);
  100.             p++;
  101.         }
  102.     }
  103.  
  104.     av_bprint_clear(&sami->full);
  105.     if (sami->source.len)
  106.         av_bprintf(&sami->full, "{\\i1}%s{\\i0}\\N", sami->source.str);
  107.     av_bprintf(&sami->full, "%s\r\n", sami->content.str);
  108.  
  109. end:
  110.     av_free(dupsrc);
  111.     return ret;
  112. }
  113.  
  114. static int sami_decode_frame(AVCodecContext *avctx,
  115.                              void *data, int *got_sub_ptr, AVPacket *avpkt)
  116. {
  117.     AVSubtitle *sub = data;
  118.     const char *ptr = avpkt->data;
  119.     SAMIContext *sami = avctx->priv_data;
  120.  
  121.     if (ptr && avpkt->size > 0 && !sami_paragraph_to_ass(avctx, ptr)) {
  122.         int ts_start     = av_rescale_q(avpkt->pts, avctx->time_base, (AVRational){1,100});
  123.         int ts_duration  = avpkt->duration != -1 ?
  124.                            av_rescale_q(avpkt->duration, avctx->time_base, (AVRational){1,100}) : -1;
  125.         ff_ass_add_rect(sub, sami->full.str, ts_start, ts_duration, 0);
  126.     }
  127.     *got_sub_ptr = sub->num_rects > 0;
  128.     return avpkt->size;
  129. }
  130.  
  131. static av_cold int sami_init(AVCodecContext *avctx)
  132. {
  133.     SAMIContext *sami = avctx->priv_data;
  134.     av_bprint_init(&sami->source,  0, 2048);
  135.     av_bprint_init(&sami->content, 0, 2048);
  136.     av_bprint_init(&sami->full,    0, 2048);
  137.     return ff_ass_subtitle_header_default(avctx);
  138. }
  139.  
  140. static av_cold int sami_close(AVCodecContext *avctx)
  141. {
  142.     SAMIContext *sami = avctx->priv_data;
  143.     av_bprint_finalize(&sami->source,  NULL);
  144.     av_bprint_finalize(&sami->content, NULL);
  145.     av_bprint_finalize(&sami->full,    NULL);
  146.     return 0;
  147. }
  148.  
  149. AVCodec ff_sami_decoder = {
  150.     .name           = "sami",
  151.     .long_name      = NULL_IF_CONFIG_SMALL("SAMI subtitle"),
  152.     .type           = AVMEDIA_TYPE_SUBTITLE,
  153.     .id             = AV_CODEC_ID_SAMI,
  154.     .priv_data_size = sizeof(SAMIContext),
  155.     .init           = sami_init,
  156.     .close          = sami_close,
  157.     .decode         = sami_decode_frame,
  158. };
  159.