FFmpeg
subviewerdec.c
Go to the documentation of this file.
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 "internal.h"
29 #include "subtitles.h"
30 #include "avio_internal.h"
31 #include "libavcodec/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 read_ts(const char *s, int64_t *start, int *duration)
55 {
56  int64_t end;
57  int hh1, mm1, ss1, ms1;
58  int hh2, mm2, ss2, ms2;
59  int multiplier = 1;
60 
61  if (sscanf(s, "%u:%u:%u.%2u,%u:%u:%u.%2u",
62  &hh1, &mm1, &ss1, &ms1, &hh2, &mm2, &ss2, &ms2) == 8) {
63  multiplier = 10;
64  } else if (sscanf(s, "%u:%u:%u.%1u,%u:%u:%u.%1u",
65  &hh1, &mm1, &ss1, &ms1, &hh2, &mm2, &ss2, &ms2) == 8) {
66  multiplier = 100;
67  }
68  if (sscanf(s, "%u:%u:%u.%u,%u:%u:%u.%u",
69  &hh1, &mm1, &ss1, &ms1, &hh2, &mm2, &ss2, &ms2) == 8) {
70  ms1 = FFMIN(ms1, 999);
71  ms2 = FFMIN(ms2, 999);
72  end = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2 * multiplier;
73  *start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1 * multiplier;
74  *duration = end - *start;
75  return 0;
76  }
77  return -1;
78 }
79 
81 {
82  SubViewerContext *subviewer = s->priv_data;
84  AVBPrint header;
85  int res = 0, new_event = 1;
86  int64_t pts_start = AV_NOPTS_VALUE;
87  int duration = -1;
88  AVPacket *sub = NULL;
89 
90  if (!st)
91  return AVERROR(ENOMEM);
92  res = ffio_ensure_seekback(s->pb, 3);
93  if (res < 0)
94  return res;
95  if (avio_rb24(s->pb) != 0xefbbbf)
96  avio_seek(s->pb, -3, SEEK_CUR);
97  avpriv_set_pts_info(st, 64, 1, 1000);
100 
102 
103  while (!avio_feof(s->pb)) {
104  char line[2048];
105  int64_t pos = 0;
106  int len = ff_get_line(s->pb, line, sizeof(line));
107 
108  if (!len)
109  break;
110 
111  line[strcspn(line, "\r\n")] = 0;
112 
113  if (line[0] == '[' && strncmp(line, "[br]", 4)) {
114 
115  /* ignore event style, XXX: add to side_data? */
116  if (strstr(line, "[COLF]") || strstr(line, "[SIZE]") ||
117  strstr(line, "[FONT]") || strstr(line, "[STYLE]"))
118  continue;
119 
120  if (!st->codecpar->extradata) { // header not finalized yet
121  av_bprintf(&header, "%s\n", line);
122  if (!strncmp(line, "[END INFORMATION]", 17) || !strncmp(line, "[SUBTITLE]", 10)) {
123  /* end of header */
124  res = ff_bprint_to_codecpar_extradata(st->codecpar, &header);
125  if (res < 0)
126  goto end;
127  } else if (strncmp(line, "[INFORMATION]", 13)) {
128  /* assume file metadata at this point */
129  int i, j = 0;
130  char key[32], value[128];
131 
132  for (i = 1; i < sizeof(key) - 1 && line[i] && line[i] != ']'; i++)
133  key[i - 1] = av_tolower(line[i]);
134  key[i - 1] = 0;
135 
136  if (line[i] == ']')
137  i++;
138  while (line[i] == ' ')
139  i++;
140  while (j < sizeof(value) - 1 && line[i] && line[i] != ']')
141  value[j++] = line[i++];
142  value[j] = 0;
143 
144  av_dict_set(&s->metadata, key, value, 0);
145  }
146  }
147  } else if (read_ts(line, &pts_start, &duration) >= 0) {
148  new_event = 1;
149  pos = avio_tell(s->pb);
150  } else if (*line) {
151  if (pts_start == AV_NOPTS_VALUE) {
152  res = AVERROR_INVALIDDATA;
153  goto end;
154  }
155  if (!new_event) {
156  sub = ff_subtitles_queue_insert(&subviewer->q, "\n", 1, 1);
157  if (!sub) {
158  res = AVERROR(ENOMEM);
159  goto end;
160  }
161  }
162  sub = ff_subtitles_queue_insert(&subviewer->q, line, strlen(line), !new_event);
163  if (!sub) {
164  res = AVERROR(ENOMEM);
165  goto end;
166  }
167  if (new_event) {
168  sub->pos = pos;
169  sub->pts = pts_start;
170  sub->duration = duration;
171  }
172  new_event = 0;
173  }
174  }
175 
176  ff_subtitles_queue_finalize(s, &subviewer->q);
177 
178 end:
179  if (res < 0)
180  ff_subtitles_queue_clean(&subviewer->q);
181  av_bprint_finalize(&header, NULL);
182  return res;
183 }
184 
186 {
187  SubViewerContext *subviewer = s->priv_data;
188  return ff_subtitles_queue_read_packet(&subviewer->q, pkt);
189 }
190 
191 static int subviewer_read_seek(AVFormatContext *s, int stream_index,
192  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
193 {
194  SubViewerContext *subviewer = s->priv_data;
195  return ff_subtitles_queue_seek(&subviewer->q, s, stream_index,
196  min_ts, ts, max_ts, flags);
197 }
198 
200 {
201  SubViewerContext *subviewer = s->priv_data;
202  ff_subtitles_queue_clean(&subviewer->q);
203  return 0;
204 }
205 
207  .name = "subviewer",
208  .long_name = NULL_IF_CONFIG_SMALL("SubViewer subtitle format"),
209  .priv_data_size = sizeof(SubViewerContext),
213  .read_seek2 = subviewer_read_seek,
215  .extensions = "sub",
216 };
#define NULL
Definition: coverity.c:32
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:94
static int subviewer_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Definition: subviewerdec.c:191
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:383
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4871
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:253
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:302
const char * key
static AVPacket pkt
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:235
Format I/O context.
Definition: avformat.h:1239
int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
Generic read_packet() callback for subtitles demuxers using this queue system.
Definition: subtitles.c:212
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:92
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:381
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
GLsizei GLboolean const GLfloat * value
Definition: opengl_enc.c:108
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4453
int64_t duration
Definition: movenc.c:63
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:145
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
static const uint8_t header[24]
Definition: sdr2.c:67
static av_const int av_tolower(int c)
Locale-independent conversion of ASCII characters to lowercase.
Definition: avstring.h:246
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1479
#define AV_BPRINT_SIZE_UNLIMITED
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:69
unsigned int pos
Definition: spdifenc.c:410
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
Definition: graph2dot.c:48
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:776
#define FFMIN(a, b)
Definition: common.h:96
#define s(width, name)
Definition: cbs_vp9.c:257
int ff_get_line(AVIOContext *s, char *buf, int maxlen)
Read a whole line of text from AVIOContext.
Definition: aviobuf.c:791
static int subviewer_probe(const AVProbeData *p)
Definition: subviewerdec.c:40
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:527
Stream structure.
Definition: avformat.h:880
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Update current_sub_idx to emulate a seek.
Definition: subtitles.c:250
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:91
AVIOContext * pb
I/O context.
Definition: avformat.h:1281
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:70
int ff_bprint_to_codecpar_extradata(AVCodecParameters *par, struct AVBPrint *buf)
Finalize buf into extradata and set its size appropriately.
Definition: utils.c:5681
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:451
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
static int read_ts(const char *s, int64_t *start, int *duration)
Definition: subviewerdec.c:54
#define flags(name, subs,...)
Definition: cbs_av1.c:560
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)
Ensures that the requested seekback buffer size will be available.
Definition: aviobuf.c:1000
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
Main libavformat public API header.
common internal api header.
static int subviewer_read_header(AVFormatContext *s)
Definition: subviewerdec.c:80
AVInputFormat ff_subviewer_demuxer
Definition: subviewerdec.c:206
int len
static int subviewer_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: subviewerdec.c:185
void * priv_data
Format private data.
Definition: avformat.h:1267
static int subviewer_read_close(AVFormatContext *s)
Definition: subviewerdec.c:199
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: codec_par.h:74
FFDemuxSubtitlesQueue q
Definition: subviewerdec.c:37
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:652
static float sub(float src0, float src1)
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1045
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:368
AVPacket * ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q, const uint8_t *event, size_t len, int merge)
Insert a new subtitle event.
Definition: subtitles.c:111
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
This structure stores compressed data.
Definition: packet.h:340
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:194
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:356
int i
Definition: input.c:407
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248