FFmpeg: libavcodec/dvbsub_parser.c Source File

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 #include "avcodec.h"
22 #include "get_bits.h"
23 #include "internal.h"
24 
25 /* Parser (mostly) copied from dvdsub.c */
26 
27  #define PARSE_BUF_SIZE (65536)
28 
29 
30 /* parser definition */
31  typedef struct DVBSubParseContext {
32   uint8_t *packet_buf;
33   int packet_start;
34   int packet_index;
35   int in_packet;
36 } DVBSubParseContext;
37 
38  static av_cold int dvbsub_parse_init(AVCodecParserContext *s)
39 {
40  DVBSubParseContext *pc = s->priv_data;
41  pc->packet_buf = av_malloc(PARSE_BUF_SIZE);
42 
43  return 0;
44 }
45 
46  static int dvbsub_parse(AVCodecParserContext *s,
47  AVCodecContext *avctx,
48  const uint8_t **poutbuf, int *poutbuf_size,
49  const uint8_t *buf, int buf_size)
50 {
51  DVBSubParseContext *pc = s->priv_data;
52  uint8_t *p, *p_end;
53  int i, len, buf_pos = 0;
54 
55  ff_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
56  s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
57 
58  for (i=0; i < buf_size; i++)
59  {
60  ff_dlog(avctx, "%02x ", buf[i]);
61  if (i % 16 == 15)
62  ff_dlog(avctx, "\n");
63  }
64 
65  if (i % 16 != 0)
66  ff_dlog(avctx, "\n");
67 
68  *poutbuf = NULL;
69  *poutbuf_size = 0;
70 
71  s->fetch_timestamp = 1;
72 
73  if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
74  {
75  if (pc->packet_index != pc->packet_start)
76  {
77  ff_dlog(avctx, "Discarding %d bytes\n",
78  pc->packet_index - pc->packet_start);
79  }
80 
81  pc->packet_start = 0;
82  pc->packet_index = 0;
83 
84  if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
85  ff_dlog(avctx, "Bad packet header\n");
86  return -1;
87  }
88 
89  buf_pos = 2;
90 
91  pc->in_packet = 1;
92  } else {
93  if (pc->packet_start != 0)
94  {
95  if (pc->packet_index != pc->packet_start)
96  {
97  memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
98  pc->packet_index - pc->packet_start);
99 
100  pc->packet_index -= pc->packet_start;
101  pc->packet_start = 0;
102  } else {
103  pc->packet_start = 0;
104  pc->packet_index = 0;
105  }
106  }
107  }
108 
109  if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
110  return -1;
111 
112 /* if not currently in a packet, discard data */
113  if (pc->in_packet == 0)
114  return buf_size;
115 
116  memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
117  pc->packet_index += buf_size - buf_pos;
118 
119  p = pc->packet_buf;
120  p_end = pc->packet_buf + pc->packet_index;
121 
122  while (p < p_end)
123  {
124  if (*p == 0x0f)
125  {
126  if (6 <= p_end - p)
127  {
128  len = AV_RB16(p + 4);
129 
130  if (len + 6 <= p_end - p)
131  {
132  *poutbuf_size += len + 6;
133 
134  p += len + 6;
135  } else
136  break;
137  } else
138  break;
139  } else if (*p == 0xff) {
140  if (1 < p_end - p)
141  {
142  ff_dlog(avctx, "Junk at end of packet\n");
143  }
144  pc->packet_index = p - pc->packet_buf;
145  pc->in_packet = 0;
146  break;
147  } else {
148  av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
149 
150  pc->packet_index = p - pc->packet_buf;
151  pc->in_packet = 0;
152  break;
153  }
154  }
155 
156  if (*poutbuf_size > 0)
157  {
158  *poutbuf = pc->packet_buf;
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 
168  static av_cold void dvbsub_parse_close(AVCodecParserContext *s)
169 {
170  DVBSubParseContext *pc = s->priv_data;
171  av_freep(&pc->packet_buf);
172 }
173 
174  AVCodecParser ff_dvbsub_parser = {
175  .codec_ids = { AV_CODEC_ID_DVB_SUBTITLE },
176  .priv_data_size = sizeof(DVBSubParseContext),
177  .parser_init = dvbsub_parse_init,
178  .parser_parse = dvbsub_parse,
179  .parser_close = dvbsub_parse_close,
180 };
ff_dvbsub_parser
AVCodecParser ff_dvbsub_parser
Definition: dvbsub_parser.c:174
NULL
#define NULL
Definition: coverity.c:32
s
const char * s
Definition: avisynth_c.h:631
dvbsub_parse_close
static av_cold void dvbsub_parse_close(AVCodecParserContext *s)
Definition: dvbsub_parser.c:168
AVCodecParser::codec_ids
int codec_ids[5]
Definition: avcodec.h:4589
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:87
dvbsub_parse_init
static av_cold int dvbsub_parse_init(AVCodecParserContext *s)
Definition: dvbsub_parser.c:38
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:46
uint8_t
uint8_t
Definition: audio_convert.c:194
av_cold
#define av_cold
Definition: attributes.h:82
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:31
ff_dlog
#define ff_dlog(a,...)
Definition: tableprint_vlc.h:29
get_bits.h
bitstream reader API header.
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
PARSE_BUF_SIZE
#define PARSE_BUF_SIZE
Definition: dvbsub_parser.c:27
AVCodecParserContext::priv_data
void * priv_data
Definition: avcodec.h:4422
DVBSubParseContext::packet_buf
uint8_t * packet_buf
Definition: dvbsub_parser.c:32
AVCodecParserContext::cur_frame_pts
int64_t cur_frame_pts[AV_PARSER_PTS_NB]
Definition: avcodec.h:4451
avcodec.h
Libavcodec external API header.
AVCodecContext
main external API structure.
Definition: avcodec.h:1532
AVCodecParserContext::cur_frame_start_index
int cur_frame_start_index
Definition: avcodec.h:4449
AV_CODEC_ID_DVB_SUBTITLE
Definition: avcodec.h:507
buf
void * buf
Definition: avisynth_c.h:553
internal.h
common internal api header.
AVCodecParserContext::last_pts
int64_t last_pts
Definition: avcodec.h:4444
len
int len
Definition: vorbis_enc_data.h:452
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:240
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