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 
27 #include "avcodec.h"
28 
29 /* Parser (mostly) copied from dvdsub.c */
30 
31 #define PARSE_BUF_SIZE (65536)
32 
33 
34 /* parser definition */
35 typedef struct DVBSubParseContext {
38  int in_packet;
41 
43  AVCodecContext *avctx,
44  const uint8_t **poutbuf, int *poutbuf_size,
45  const uint8_t *buf, int buf_size)
46 {
47  DVBSubParseContext *pc = s->priv_data;
48  uint8_t *p, *p_end;
49  int i, len, buf_pos = 0;
50  int out_size = 0;
51 
52  ff_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
53  s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
54 
55  for (i=0; i < buf_size; i++)
56  {
57  ff_dlog(avctx, "%02x ", buf[i]);
58  if (i % 16 == 15)
59  ff_dlog(avctx, "\n");
60  }
61 
62  if (i % 16 != 0)
63  ff_dlog(avctx, "\n");
64 
65  *poutbuf = buf;
66  *poutbuf_size = buf_size;
67 
68  s->fetch_timestamp = 1;
69 
70  if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
71  {
72  if (pc->packet_index != pc->packet_start)
73  {
74  ff_dlog(avctx, "Discarding %d bytes\n",
75  pc->packet_index - pc->packet_start);
76  }
77 
78  pc->packet_start = 0;
79  pc->packet_index = 0;
80 
81  if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
82  ff_dlog(avctx, "Bad packet header\n");
83  return buf_size;
84  }
85 
86  buf_pos = 2;
87 
88  pc->in_packet = 1;
89  } else {
90  if (pc->packet_start != 0)
91  {
92  if (pc->packet_index != pc->packet_start)
93  {
94  memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
95  pc->packet_index - pc->packet_start);
96 
97  pc->packet_index -= pc->packet_start;
98  pc->packet_start = 0;
99  } else {
100  pc->packet_start = 0;
101  pc->packet_index = 0;
102  }
103  }
104  }
105 
106  if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
107  return buf_size;
108 
109 /* if not currently in a packet, pass data */
110  if (pc->in_packet == 0)
111  return buf_size;
112 
113  memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
114  pc->packet_index += buf_size - buf_pos;
115 
116  p = pc->packet_buf;
117  p_end = pc->packet_buf + pc->packet_index;
118 
119  while (p < p_end)
120  {
121  if (*p == 0x0f)
122  {
123  if (6 <= p_end - p)
124  {
125  len = AV_RB16(p + 4);
126 
127  if (len + 6 <= p_end - p)
128  {
129  out_size += len + 6;
130 
131  p += len + 6;
132  } else
133  break;
134  } else
135  break;
136  } else if (*p == 0xff) {
137  if (1 < p_end - p)
138  {
139  ff_dlog(avctx, "Junk at end of packet\n");
140  }
141  pc->packet_index = p - pc->packet_buf;
142  pc->in_packet = 0;
143  break;
144  } else {
145  av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
146 
147  pc->packet_index = p - pc->packet_buf;
148  pc->in_packet = 0;
149  break;
150  }
151  }
152 
153  if (out_size > 0)
154  {
155  *poutbuf = pc->packet_buf;
156  *poutbuf_size = out_size;
157  pc->packet_start = *poutbuf_size;
158  }
159 
160  if (s->pts == AV_NOPTS_VALUE)
161  s->pts = s->last_pts;
162 
163  return buf_size;
164 }
165 
168  .priv_data_size = sizeof(DVBSubParseContext),
169  .parser_parse = dvbsub_parse,
170 };
DVBSubParseContext::packet_start
int packet_start
Definition: dvbsub_parser.c:36
out_size
int out_size
Definition: movenc.c:55
DVBSubParseContext::packet_index
int packet_index
Definition: dvbsub_parser.c:37
AV_CODEC_ID_DVB_SUBTITLE
@ AV_CODEC_ID_DVB_SUBTITLE
Definition: codec_id.h:526
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:256
DVBSubParseContext::packet_buf
uint8_t packet_buf[PARSE_BUF_SIZE]
Definition: dvbsub_parser.c:39
ff_dlog
#define ff_dlog(a,...)
Definition: tableprint_vlc.h:28
AVCodecParser::codec_ids
int codec_ids[7]
Definition: avcodec.h:2950
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
PARSE_BUF_SIZE
#define PARSE_BUF_SIZE
Definition: dvbsub_parser.c:31
DVBSubParseContext
Definition: dvbsub_parser.c:35
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
len
int len
Definition: vorbis_enc_data.h:426
avcodec.h
AVCodecParserContext
Definition: avcodec.h:2790
DVBSubParseContext::in_packet
int in_packet
Definition: dvbsub_parser.c:38
AVCodecContext
main external API structure.
Definition: avcodec.h:389
ff_dvbsub_parser
const AVCodecParser ff_dvbsub_parser
Definition: dvbsub_parser.c:166
AVCodecParser
Definition: avcodec.h:2949
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
dvbsub_parse
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:42
AV_RB16
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:98