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dvbsub_parser.c
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1 /*
2  * DVB subtitle parser for FFmpeg
3  * Copyright (c) 2005 Ian Caulfield
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <inttypes.h>
23 #include <string.h>
24 
25 #include "libavutil/intreadwrite.h"
26 #include "libavutil/mem.h"
27 
28 #include "avcodec.h"
29 #include "internal.h"
30 
31 /* Parser (mostly) copied from dvdsub.c */
32 
33 #define PARSE_BUF_SIZE (65536)
34 
35 
36 /* parser definition */
37 typedef struct DVBSubParseContext {
41  int in_packet;
43 
45 {
48 
49  return 0;
50 }
51 
53  AVCodecContext *avctx,
54  const uint8_t **poutbuf, int *poutbuf_size,
55  const uint8_t *buf, int buf_size)
56 {
58  uint8_t *p, *p_end;
59  int i, len, buf_pos = 0;
60 
61  ff_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
63 
64  for (i=0; i < buf_size; i++)
65  {
66  ff_dlog(avctx, "%02x ", buf[i]);
67  if (i % 16 == 15)
68  ff_dlog(avctx, "\n");
69  }
70 
71  if (i % 16 != 0)
72  ff_dlog(avctx, "\n");
73 
74  *poutbuf = NULL;
75  *poutbuf_size = 0;
76 
77  s->fetch_timestamp = 1;
78 
79  if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
80  {
81  if (pc->packet_index != pc->packet_start)
82  {
83  ff_dlog(avctx, "Discarding %d bytes\n",
84  pc->packet_index - pc->packet_start);
85  }
86 
87  pc->packet_start = 0;
88  pc->packet_index = 0;
89 
90  if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
91  ff_dlog(avctx, "Bad packet header\n");
92  return -1;
93  }
94 
95  buf_pos = 2;
96 
97  pc->in_packet = 1;
98  } else {
99  if (pc->packet_start != 0)
100  {
101  if (pc->packet_index != pc->packet_start)
102  {
103  memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
104  pc->packet_index - pc->packet_start);
105 
106  pc->packet_index -= pc->packet_start;
107  pc->packet_start = 0;
108  } else {
109  pc->packet_start = 0;
110  pc->packet_index = 0;
111  }
112  }
113  }
114 
115  if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
116  return -1;
117 
118 /* if not currently in a packet, discard data */
119  if (pc->in_packet == 0)
120  return buf_size;
121 
122  memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
123  pc->packet_index += buf_size - buf_pos;
124 
125  p = pc->packet_buf;
126  p_end = pc->packet_buf + pc->packet_index;
127 
128  while (p < p_end)
129  {
130  if (*p == 0x0f)
131  {
132  if (6 <= p_end - p)
133  {
134  len = AV_RB16(p + 4);
135 
136  if (len + 6 <= p_end - p)
137  {
138  *poutbuf_size += len + 6;
139 
140  p += len + 6;
141  } else
142  break;
143  } else
144  break;
145  } else if (*p == 0xff) {
146  if (1 < p_end - p)
147  {
148  ff_dlog(avctx, "Junk at end of packet\n");
149  }
150  pc->packet_index = p - pc->packet_buf;
151  pc->in_packet = 0;
152  break;
153  } else {
154  av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
155 
156  pc->packet_index = p - pc->packet_buf;
157  pc->in_packet = 0;
158  break;
159  }
160  }
161 
162  if (*poutbuf_size > 0)
163  {
164  *poutbuf = pc->packet_buf;
165  pc->packet_start = *poutbuf_size;
166  }
167 
168  if (s->pts == AV_NOPTS_VALUE)
169  s->pts = s->last_pts;
170 
171  return buf_size;
172 }
173 
175 {
176  DVBSubParseContext *pc = s->priv_data;
177  av_freep(&pc->packet_buf);
178 }
179 
182  .priv_data_size = sizeof(DVBSubParseContext),
183  .parser_init = dvbsub_parse_init,
184  .parser_parse = dvbsub_parse,
185  .parser_close = dvbsub_parse_close,
186 };
AVCodecParser ff_dvbsub_parser
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
static av_cold void dvbsub_parse_close(AVCodecParserContext *s)
Memory handling functions.
int codec_ids[5]
Definition: avcodec.h:5138
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:87
static av_cold int dvbsub_parse_init(AVCodecParserContext *s)
Definition: dvbsub_parser.c:44
static int dvbsub_parse(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: dvbsub_parser.c:52
uint8_t
#define av_cold
Definition: attributes.h:82
#define av_malloc(s)
#define ff_dlog(a,...)
#define av_log(a,...)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define PARSE_BUF_SIZE
Definition: dvbsub_parser.c:33
uint8_t * packet_buf
Definition: dvbsub_parser.c:38
int64_t cur_frame_pts[AV_PARSER_PTS_NB]
Definition: avcodec.h:5000
Libavcodec external API header.
main external API structure.
Definition: avcodec.h:1675
void * buf
Definition: avisynth_c.h:690
common internal api header.
int len
#define av_freep(p)
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:242