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 #include "internal.h"
29 
30 /* Parser (mostly) copied from dvdsub.c */
31 
32 #define PARSE_BUF_SIZE (65536)
33 
34 
35 /* parser definition */
36 typedef struct DVBSubParseContext {
39  int in_packet;
42 
44  AVCodecContext *avctx,
45  const uint8_t **poutbuf, int *poutbuf_size,
46  const uint8_t *buf, int buf_size)
47 {
48  DVBSubParseContext *pc = s->priv_data;
49  uint8_t *p, *p_end;
50  int i, len, buf_pos = 0;
51  int out_size = 0;
52 
53  ff_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
54  s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
55 
56  for (i=0; i < buf_size; i++)
57  {
58  ff_dlog(avctx, "%02x ", buf[i]);
59  if (i % 16 == 15)
60  ff_dlog(avctx, "\n");
61  }
62 
63  if (i % 16 != 0)
64  ff_dlog(avctx, "\n");
65 
66  *poutbuf = buf;
67  *poutbuf_size = buf_size;
68 
69  s->fetch_timestamp = 1;
70 
71  if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
72  {
73  if (pc->packet_index != pc->packet_start)
74  {
75  ff_dlog(avctx, "Discarding %d bytes\n",
76  pc->packet_index - pc->packet_start);
77  }
78 
79  pc->packet_start = 0;
80  pc->packet_index = 0;
81 
82  if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
83  ff_dlog(avctx, "Bad packet header\n");
84  return buf_size;
85  }
86 
87  buf_pos = 2;
88 
89  pc->in_packet = 1;
90  } else {
91  if (pc->packet_start != 0)
92  {
93  if (pc->packet_index != pc->packet_start)
94  {
95  memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
96  pc->packet_index - pc->packet_start);
97 
98  pc->packet_index -= pc->packet_start;
99  pc->packet_start = 0;
100  } else {
101  pc->packet_start = 0;
102  pc->packet_index = 0;
103  }
104  }
105  }
106 
107  if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
108  return buf_size;
109 
110 /* if not currently in a packet, pass data */
111  if (pc->in_packet == 0)
112  return buf_size;
113 
114  memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
115  pc->packet_index += buf_size - buf_pos;
116 
117  p = pc->packet_buf;
118  p_end = pc->packet_buf + pc->packet_index;
119 
120  while (p < p_end)
121  {
122  if (*p == 0x0f)
123  {
124  if (6 <= p_end - p)
125  {
126  len = AV_RB16(p + 4);
127 
128  if (len + 6 <= p_end - p)
129  {
130  out_size += len + 6;
131 
132  p += len + 6;
133  } else
134  break;
135  } else
136  break;
137  } else if (*p == 0xff) {
138  if (1 < p_end - p)
139  {
140  ff_dlog(avctx, "Junk at end of packet\n");
141  }
142  pc->packet_index = p - pc->packet_buf;
143  pc->in_packet = 0;
144  break;
145  } else {
146  av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
147 
148  pc->packet_index = p - pc->packet_buf;
149  pc->in_packet = 0;
150  break;
151  }
152  }
153 
154  if (out_size > 0)
155  {
156  *poutbuf = pc->packet_buf;
157  *poutbuf_size = out_size;
158  pc->packet_start = *poutbuf_size;
159  }
160 
161  if (s->pts == AV_NOPTS_VALUE)
162  s->pts = s->last_pts;
163 
164  return buf_size;
165 }
166 
169  .priv_data_size = sizeof(DVBSubParseContext),
170  .parser_parse = dvbsub_parse,
171 };
DVBSubParseContext::packet_start
int packet_start
Definition: dvbsub_parser.c:37
out_size
int out_size
Definition: movenc.c:55
internal.h
DVBSubParseContext::packet_index
int packet_index
Definition: dvbsub_parser.c:38
AV_CODEC_ID_DVB_SUBTITLE
@ AV_CODEC_ID_DVB_SUBTITLE
Definition: codec_id.h:522
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:257
DVBSubParseContext::packet_buf
uint8_t packet_buf[PARSE_BUF_SIZE]
Definition: dvbsub_parser.c:40
ff_dlog
#define ff_dlog(a,...)
Definition: tableprint_vlc.h:29
AVCodecParser::codec_ids
int codec_ids[7]
Definition: avcodec.h:2935
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:32
DVBSubParseContext
Definition: dvbsub_parser.c:36
i
int i
Definition: input.c:406
len
int len
Definition: vorbis_enc_data.h:426
avcodec.h
AVCodecParserContext
Definition: avcodec.h:2775
DVBSubParseContext::in_packet
int in_packet
Definition: dvbsub_parser.c:39
AVCodecContext
main external API structure.
Definition: avcodec.h:383
ff_dvbsub_parser
const AVCodecParser ff_dvbsub_parser
Definition: dvbsub_parser.c:167
AVCodecParser
Definition: avcodec.h:2934
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
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:43
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