FFmpeg
subviewerdec.c
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1 /*
2  * Copyright (c) 2012 Clément Bœsch
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * SubViewer subtitle demuxer
24  * @see https://en.wikipedia.org/wiki/SubViewer
25  */
26 
27 #include "avformat.h"
28 #include "demux.h"
29 #include "internal.h"
30 #include "subtitles.h"
31 #include "avio_internal.h"
32 #include "libavutil/avstring.h"
33 #include "libavutil/bprint.h"
34 #include "libavutil/intreadwrite.h"
35 
36 typedef struct {
39 
40 static int subviewer_probe(const AVProbeData *p)
41 {
42  char c;
43  const unsigned char *ptr = p->buf;
44 
45  if (AV_RB24(ptr) == 0xEFBBBF)
46  ptr += 3; /* skip UTF-8 BOM */
47  if (sscanf(ptr, "%*u:%*u:%*u.%*u,%*u:%*u:%*u.%*u%c", &c) == 1)
49  if (!strncmp(ptr, "[INFORMATION]", 13))
50  return AVPROBE_SCORE_MAX/3;
51  return 0;
52 }
53 
54 static int get_multiplier(int e) {
55  switch (e) {
56  case 1 : return 100;
57  case 2 : return 10;
58  case 3 : return 1;
59  default : return -1;
60  }
61 }
62 
63 static int read_ts(const char *s, int64_t *start, int *duration)
64 {
65  int64_t end;
66  int hh1, mm1, ss1, ms1;
67  int hh2, mm2, ss2, ms2;
68  int multiplier1, multiplier2;
69  int ms1p1, ms1p2, ms2p1, ms2p2;
70 
71  if (sscanf(s, "%u:%u:%u.%n%u%n,%u:%u:%u.%n%u%n",
72  &hh1, &mm1, &ss1, &ms1p1, &ms1, &ms1p2, &hh2, &mm2, &ss2, &ms2p1, &ms2, &ms2p2) == 8) {
73  multiplier1 = get_multiplier(ms1p2 - ms1p1);
74  multiplier2 = get_multiplier(ms2p2 - ms2p1);
75  if (multiplier1 <= 0 ||multiplier2 <= 0)
76  return -1;
77 
78  end = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2 * multiplier2;
79  *start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1 * multiplier1;
80  *duration = end - *start;
81  return 0;
82  }
83  return -1;
84 }
85 
87 {
88  SubViewerContext *subviewer = s->priv_data;
90  AVBPrint header;
91  int res = 0, new_event = 1;
92  int64_t pts_start = AV_NOPTS_VALUE;
93  int duration = -1;
94  AVPacket *sub = NULL;
95 
96  if (!st)
97  return AVERROR(ENOMEM);
98  res = ffio_ensure_seekback(s->pb, 3);
99  if (res < 0)
100  return res;
101  if (avio_rb24(s->pb) != 0xefbbbf)
102  avio_seek(s->pb, -3, SEEK_CUR);
103  avpriv_set_pts_info(st, 64, 1, 1000);
106 
108 
109  while (!avio_feof(s->pb)) {
110  char line[2048];
111  int64_t pos = 0;
112  int len = ff_get_line(s->pb, line, sizeof(line));
113 
114  if (!len)
115  break;
116 
117  line[strcspn(line, "\r\n")] = 0;
118 
119  if (line[0] == '[' && strncmp(line, "[br]", 4)) {
120 
121  /* ignore event style, XXX: add to side_data? */
122  if (strstr(line, "[COLF]") || strstr(line, "[SIZE]") ||
123  strstr(line, "[FONT]") || strstr(line, "[STYLE]"))
124  continue;
125 
126  if (!st->codecpar->extradata) { // header not finalized yet
127  av_bprintf(&header, "%s\n", line);
128  if (!strncmp(line, "[END INFORMATION]", 17) || !strncmp(line, "[SUBTITLE]", 10)) {
129  /* end of header */
131  if (res < 0)
132  goto end;
133  } else if (strncmp(line, "[INFORMATION]", 13)) {
134  /* assume file metadata at this point */
135  int i, j = 0;
136  char key[32], value[128];
137 
138  for (i = 1; i < sizeof(key) - 1 && line[i] && line[i] != ']'; i++)
139  key[i - 1] = av_tolower(line[i]);
140  key[i - 1] = 0;
141 
142  if (line[i] == ']')
143  i++;
144  while (line[i] == ' ')
145  i++;
146  while (j < sizeof(value) - 1 && line[i] && line[i] != ']')
147  value[j++] = line[i++];
148  value[j] = 0;
149 
150  av_dict_set(&s->metadata, key, value, 0);
151  }
152  }
153  } else if (read_ts(line, &pts_start, &duration) >= 0) {
154  new_event = 1;
155  pos = avio_tell(s->pb);
156  } else if (*line) {
157  if (pts_start == AV_NOPTS_VALUE) {
158  res = AVERROR_INVALIDDATA;
159  goto end;
160  }
161  if (!new_event) {
162  sub = ff_subtitles_queue_insert(&subviewer->q, "\n", 1, 1);
163  if (!sub) {
164  res = AVERROR(ENOMEM);
165  goto end;
166  }
167  }
168  sub = ff_subtitles_queue_insert(&subviewer->q, line, strlen(line), !new_event);
169  if (!sub) {
170  res = AVERROR(ENOMEM);
171  goto end;
172  }
173  if (new_event) {
174  sub->pos = pos;
175  sub->pts = pts_start;
176  sub->duration = duration;
177  }
178  new_event = 0;
179  }
180  }
181 
182  ff_subtitles_queue_finalize(s, &subviewer->q);
183 
184 end:
186  return res;
187 }
188 
190  .p.name = "subviewer",
191  .p.long_name = NULL_IF_CONFIG_SMALL("SubViewer subtitle format"),
192  .p.extensions = "sub",
193  .priv_data_size = sizeof(SubViewerContext),
194  .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,
198  .read_seek2 = ff_subtitles_read_seek,
200 };
AVMEDIA_TYPE_SUBTITLE
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
ff_subtitles_read_close
int ff_subtitles_read_close(AVFormatContext *s)
Definition: subtitles.c:337
AV_BPRINT_SIZE_UNLIMITED
#define AV_BPRINT_SIZE_UNLIMITED
AVCodecParameters::extradata
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: codec_par.h:69
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:51
av_bprint_init
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:69
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const struct AVCodec *c)
Add a new stream to a media file.
AVPacket::duration
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:540
ff_bprint_to_codecpar_extradata
int ff_bprint_to_codecpar_extradata(AVCodecParameters *par, struct AVBPrint *buf)
Finalize buf into extradata and set its size appropriately.
Definition: utils.c:584
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:463
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: avformat.c:853
read_close
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:143
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:494
AV_CODEC_ID_SUBVIEWER
@ AV_CODEC_ID_SUBVIEWER
Definition: codec_id.h:565
ff_subtitles_read_packet
int ff_subtitles_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: subtitles.c:323
duration
int64_t duration
Definition: movenc.c:64
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_read_callback.c:41
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:198
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:553
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:453
key
const char * key
Definition: hwcontext_opencl.c:189
FF_INFMT_FLAG_INIT_CLEANUP
#define FF_INFMT_FLAG_INIT_CLEANUP
For an FFInputFormat with this flag set read_close() needs to be called by the caller upon read_heade...
Definition: demux.h:35
AVFormatContext
Format I/O context.
Definition: avformat.h:1255
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:766
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:550
NULL
#define NULL
Definition: coverity.c:32
get_multiplier
static int get_multiplier(int e)
Definition: subviewerdec.c:54
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:451
ff_subtitles_queue_insert
AVPacket * ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q, const uint8_t *event, size_t len, int merge)
Insert a new subtitle event.
Definition: subtitles.c:109
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:461
avio_rb24
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:753
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:106
av_bprint_finalize
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:240
ff_subviewer_demuxer
const FFInputFormat ff_subviewer_demuxer
Definition: subviewerdec.c:189
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
ff_subtitles_queue_finalize
void ff_subtitles_queue_finalize(void *log_ctx, FFDemuxSubtitlesQueue *q)
Set missing durations, sort subtitles by PTS (and then byte position), and drop duplicated events.
Definition: subtitles.c:204
FFDemuxSubtitlesQueue
Definition: subtitles.h:103
FFInputFormat::p
AVInputFormat p
The public AVInputFormat.
Definition: demux.h:41
header
static const uint8_t header[24]
Definition: sdr2.c:68
ffio_ensure_seekback
int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)
Ensures that the requested seekback buffer size will be available.
Definition: aviobuf.c:1022
line
Definition: graph2dot.c:48
subviewer_probe
static int subviewer_probe(const AVProbeData *p)
Definition: subviewerdec.c:40
SubViewerContext
Definition: subviewerdec.c:36
bprint.h
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:255
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:515
avio_internal.h
read_ts
static int read_ts(const char *s, int64_t *start, int *duration)
Definition: subviewerdec.c:63
value
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default value
Definition: writing_filters.txt:86
ff_subtitles_read_seek
int ff_subtitles_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Definition: subtitles.c:329
ff_get_line
int ff_get_line(AVIOContext *s, char *buf, int maxlen)
Read a whole line of text from AVIOContext.
Definition: aviobuf.c:768
demux.h
len
int len
Definition: vorbis_enc_data.h:426
AVStream
Stream structure.
Definition: avformat.h:743
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:230
pos
unsigned int pos
Definition: spdifenc.c:413
avformat.h
av_bprintf
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:99
subtitles.h
read_probe
static int read_probe(const AVProbeData *p)
Definition: cdg.c:30
subviewer_read_header
static int subviewer_read_header(AVFormatContext *s)
Definition: subviewerdec.c:86
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:55
AVPacket
This structure stores compressed data.
Definition: packet.h:499
av_dict_set
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:88
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:542
FFInputFormat
Definition: demux.h:37
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
avstring.h
AV_RB24
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_RB24
Definition: bytestream.h:97
SubViewerContext::q
FFDemuxSubtitlesQueue q
Definition: subviewerdec.c:37
av_tolower
static av_const int av_tolower(int c)
Locale-independent conversion of ASCII characters to lowercase.
Definition: avstring.h:237
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:345