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samidec.c
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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 {
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", sami->content.str);
108 
109 end:
110  av_free(dupsrc);
111  return ret;
112 }
113 
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  int ret = ff_ass_add_rect_bprint(sub, &sami->full, ts_start, ts_duration);
126  if (ret < 0)
127  return ret;
128  }
129  *got_sub_ptr = sub->num_rects > 0;
130  return avpkt->size;
131 }
132 
133 static av_cold int sami_init(AVCodecContext *avctx)
134 {
135  SAMIContext *sami = avctx->priv_data;
136  av_bprint_init(&sami->source, 0, 2048);
137  av_bprint_init(&sami->content, 0, 2048);
138  av_bprint_init(&sami->full, 0, 2048);
139  return ff_ass_subtitle_header_default(avctx);
140 }
141 
143 {
144  SAMIContext *sami = avctx->priv_data;
145  av_bprint_finalize(&sami->source, NULL);
146  av_bprint_finalize(&sami->content, NULL);
147  av_bprint_finalize(&sami->full, NULL);
148  return 0;
149 }
150 
152  .name = "sami",
153  .long_name = NULL_IF_CONFIG_SMALL("SAMI subtitle"),
154  .type = AVMEDIA_TYPE_SUBTITLE,
155  .id = AV_CODEC_ID_SAMI,
156  .priv_data_size = sizeof(SAMIContext),
157  .init = sami_init,
158  .close = sami_close,
160 };