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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  int out_size = 0;
61 
62  ff_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
64 
65  for (i=0; i < buf_size; i++)
66  {
67  ff_dlog(avctx, "%02x ", buf[i]);
68  if (i % 16 == 15)
69  ff_dlog(avctx, "\n");
70  }
71 
72  if (i % 16 != 0)
73  ff_dlog(avctx, "\n");
74 
75  *poutbuf = buf;
76  *poutbuf_size = buf_size;
77 
78  s->fetch_timestamp = 1;
79 
80  if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
81  {
82  if (pc->packet_index != pc->packet_start)
83  {
84  ff_dlog(avctx, "Discarding %d bytes\n",
85  pc->packet_index - pc->packet_start);
86  }
87 
88  pc->packet_start = 0;
89  pc->packet_index = 0;
90 
91  if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
92  ff_dlog(avctx, "Bad packet header\n");
93  return buf_size;
94  }
95 
96  buf_pos = 2;
97 
98  pc->in_packet = 1;
99  } else {
100  if (pc->packet_start != 0)
101  {
102  if (pc->packet_index != pc->packet_start)
103  {
104  memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
105  pc->packet_index - pc->packet_start);
106 
107  pc->packet_index -= pc->packet_start;
108  pc->packet_start = 0;
109  } else {
110  pc->packet_start = 0;
111  pc->packet_index = 0;
112  }
113  }
114  }
115 
116  if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
117  return buf_size;
118 
119 /* if not currently in a packet, pass data */
120  if (pc->in_packet == 0)
121  return buf_size;
122 
123  memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
124  pc->packet_index += buf_size - buf_pos;
125 
126  p = pc->packet_buf;
127  p_end = pc->packet_buf + pc->packet_index;
128 
129  while (p < p_end)
130  {
131  if (*p == 0x0f)
132  {
133  if (6 <= p_end - p)
134  {
135  len = AV_RB16(p + 4);
136 
137  if (len + 6 <= p_end - p)
138  {
139  out_size += len + 6;
140 
141  p += len + 6;
142  } else
143  break;
144  } else
145  break;
146  } else if (*p == 0xff) {
147  if (1 < p_end - p)
148  {
149  ff_dlog(avctx, "Junk at end of packet\n");
150  }
151  pc->packet_index = p - pc->packet_buf;
152  pc->in_packet = 0;
153  break;
154  } else {
155  av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
156 
157  pc->packet_index = p - pc->packet_buf;
158  pc->in_packet = 0;
159  break;
160  }
161  }
162 
163  if (out_size > 0)
164  {
165  *poutbuf = pc->packet_buf;
166  *poutbuf_size = out_size;
167  pc->packet_start = *poutbuf_size;
168  }
169 
170  if (s->pts == AV_NOPTS_VALUE)
171  s->pts = s->last_pts;
172 
173  return buf_size;
174 }
175 
177 {
178  DVBSubParseContext *pc = s->priv_data;
179  av_freep(&pc->packet_buf);
180 }
181 
184  .priv_data_size = sizeof(DVBSubParseContext),
185  .parser_init = dvbsub_parse_init,
186  .parser_parse = dvbsub_parse,
187  .parser_close = dvbsub_parse_close,
188 };
AVCodecParser ff_dvbsub_parser
static av_cold void dvbsub_parse_close(AVCodecParserContext *s)
Memory handling functions.
int codec_ids[5]
Definition: avcodec.h:5215
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 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
#define s(width, name)
Definition: cbs_vp9.c:257
int64_t cur_frame_pts[AV_PARSER_PTS_NB]
Definition: avcodec.h:5077
Libavcodec external API header.
main external API structure.
Definition: avcodec.h:1532
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:248