FFmpeg
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 {
40  int in_packet;
43 
45  AVCodecContext *avctx,
46  const uint8_t **poutbuf, int *poutbuf_size,
47  const uint8_t *buf, int buf_size)
48 {
50  uint8_t *p, *p_end;
51  int i, len, buf_pos = 0;
52  int out_size = 0;
53 
54  ff_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
56 
57  for (i=0; i < buf_size; i++)
58  {
59  ff_dlog(avctx, "%02x ", buf[i]);
60  if (i % 16 == 15)
61  ff_dlog(avctx, "\n");
62  }
63 
64  if (i % 16 != 0)
65  ff_dlog(avctx, "\n");
66 
67  *poutbuf = buf;
68  *poutbuf_size = buf_size;
69 
70  s->fetch_timestamp = 1;
71 
72  if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
73  {
74  if (pc->packet_index != pc->packet_start)
75  {
76  ff_dlog(avctx, "Discarding %d bytes\n",
77  pc->packet_index - pc->packet_start);
78  }
79 
80  pc->packet_start = 0;
81  pc->packet_index = 0;
82 
83  if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
84  ff_dlog(avctx, "Bad packet header\n");
85  return buf_size;
86  }
87 
88  buf_pos = 2;
89 
90  pc->in_packet = 1;
91  } else {
92  if (pc->packet_start != 0)
93  {
94  if (pc->packet_index != pc->packet_start)
95  {
96  memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
97  pc->packet_index - pc->packet_start);
98 
99  pc->packet_index -= pc->packet_start;
100  pc->packet_start = 0;
101  } else {
102  pc->packet_start = 0;
103  pc->packet_index = 0;
104  }
105  }
106  }
107 
108  if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
109  return buf_size;
110 
111 /* if not currently in a packet, pass data */
112  if (pc->in_packet == 0)
113  return buf_size;
114 
115  memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
116  pc->packet_index += buf_size - buf_pos;
117 
118  p = pc->packet_buf;
119  p_end = pc->packet_buf + pc->packet_index;
120 
121  while (p < p_end)
122  {
123  if (*p == 0x0f)
124  {
125  if (6 <= p_end - p)
126  {
127  len = AV_RB16(p + 4);
128 
129  if (len + 6 <= p_end - p)
130  {
131  out_size += len + 6;
132 
133  p += len + 6;
134  } else
135  break;
136  } else
137  break;
138  } else if (*p == 0xff) {
139  if (1 < p_end - p)
140  {
141  ff_dlog(avctx, "Junk at end of packet\n");
142  }
143  pc->packet_index = p - pc->packet_buf;
144  pc->in_packet = 0;
145  break;
146  } else {
147  av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
148 
149  pc->packet_index = p - pc->packet_buf;
150  pc->in_packet = 0;
151  break;
152  }
153  }
154 
155  if (out_size > 0)
156  {
157  *poutbuf = pc->packet_buf;
158  *poutbuf_size = out_size;
159  pc->packet_start = *poutbuf_size;
160  }
161 
162  if (s->pts == AV_NOPTS_VALUE)
163  s->pts = s->last_pts;
164 
165  return buf_size;
166 }
167 
170  .priv_data_size = sizeof(DVBSubParseContext),
171  .parser_parse = dvbsub_parse,
172 };
AVCodecParser ff_dvbsub_parser
Memory handling functions.
uint8_t packet_buf[PARSE_BUF_SIZE]
Definition: dvbsub_parser.c:41
int codec_ids[5]
Definition: avcodec.h:3521
int out_size
Definition: movenc.c:55
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 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:44
uint8_t
#define ff_dlog(a,...)
#define av_log(a,...)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
#define PARSE_BUF_SIZE
Definition: dvbsub_parser.c:33
#define s(width, name)
Definition: cbs_vp9.c:257
int64_t cur_frame_pts[AV_PARSER_PTS_NB]
Definition: avcodec.h:3383
Libavcodec external API header.
main external API structure.
Definition: avcodec.h:526
common internal api header.
int len
int i
Definition: input.c:407
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248