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 
60  if (sscanf(s, "%u:%u:%u.%u,%u:%u:%u.%u",
61  &hh1, &mm1, &ss1, &ms1, &hh2, &mm2, &ss2, &ms2) == 8) {
62  end = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
63  *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
64  *duration = end - *start;
65  return 0;
66  }
67  return -1;
68 }
69 
71 {
72  SubViewerContext *subviewer = s->priv_data;
74  AVBPrint header;
75  int res = 0, new_event = 1;
76  int64_t pts_start = AV_NOPTS_VALUE;
77  int duration = -1;
78  AVPacket *sub = NULL;
79 
80  if (!st)
81  return AVERROR(ENOMEM);
82  res = ffio_ensure_seekback(s->pb, 3);
83  if (res < 0)
84  return res;
85  if (avio_rb24(s->pb) != 0xefbbbf)
86  avio_seek(s->pb, -3, SEEK_CUR);
87  avpriv_set_pts_info(st, 64, 1, 100);
90 
92 
93  while (!avio_feof(s->pb)) {
94  char line[2048];
95  int64_t pos = 0;
96  int len = ff_get_line(s->pb, line, sizeof(line));
97 
98  if (!len)
99  break;
100 
101  line[strcspn(line, "\r\n")] = 0;
102 
103  if (line[0] == '[' && strncmp(line, "[br]", 4)) {
104 
105  /* ignore event style, XXX: add to side_data? */
106  if (strstr(line, "[COLF]") || strstr(line, "[SIZE]") ||
107  strstr(line, "[FONT]") || strstr(line, "[STYLE]"))
108  continue;
109 
110  if (!st->codecpar->extradata) { // header not finalized yet
111  av_bprintf(&header, "%s\n", line);
112  if (!strncmp(line, "[END INFORMATION]", 17) || !strncmp(line, "[SUBTITLE]", 10)) {
113  /* end of header */
114  res = ff_bprint_to_codecpar_extradata(st->codecpar, &header);
115  if (res < 0)
116  goto end;
117  } else if (strncmp(line, "[INFORMATION]", 13)) {
118  /* assume file metadata at this point */
119  int i, j = 0;
120  char key[32], value[128];
121 
122  for (i = 1; i < sizeof(key) - 1 && line[i] && line[i] != ']'; i++)
123  key[i - 1] = av_tolower(line[i]);
124  key[i - 1] = 0;
125 
126  if (line[i] == ']')
127  i++;
128  while (line[i] == ' ')
129  i++;
130  while (j < sizeof(value) - 1 && line[i] && line[i] != ']')
131  value[j++] = line[i++];
132  value[j] = 0;
133 
134  av_dict_set(&s->metadata, key, value, 0);
135  }
136  }
137  } else if (read_ts(line, &pts_start, &duration) >= 0) {
138  new_event = 1;
139  pos = avio_tell(s->pb);
140  } else if (*line) {
141  if (!new_event) {
142  sub = ff_subtitles_queue_insert(&subviewer->q, "\n", 1, 1);
143  if (!sub) {
144  res = AVERROR(ENOMEM);
145  goto end;
146  }
147  }
148  sub = ff_subtitles_queue_insert(&subviewer->q, line, strlen(line), !new_event);
149  if (!sub) {
150  res = AVERROR(ENOMEM);
151  goto end;
152  }
153  if (new_event) {
154  sub->pos = pos;
155  sub->pts = pts_start;
156  sub->duration = duration;
157  }
158  new_event = 0;
159  }
160  }
161 
162  ff_subtitles_queue_finalize(s, &subviewer->q);
163 
164 end:
165  av_bprint_finalize(&header, NULL);
166  return res;
167 }
168 
170 {
171  SubViewerContext *subviewer = s->priv_data;
172  return ff_subtitles_queue_read_packet(&subviewer->q, pkt);
173 }
174 
175 static int subviewer_read_seek(AVFormatContext *s, int stream_index,
176  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
177 {
178  SubViewerContext *subviewer = s->priv_data;
179  return ff_subtitles_queue_seek(&subviewer->q, s, stream_index,
180  min_ts, ts, max_ts, flags);
181 }
182 
184 {
185  SubViewerContext *subviewer = s->priv_data;
186  ff_subtitles_queue_clean(&subviewer->q);
187  return 0;
188 }
189 
191  .name = "subviewer",
192  .long_name = NULL_IF_CONFIG_SMALL("SubViewer subtitle format"),
193  .priv_data_size = sizeof(SubViewerContext),
197  .read_seek2 = subviewer_read_seek,
199  .extensions = "sub",
200 };
#define NULL
Definition: coverity.c:32
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:175
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1502
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:4929
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3970
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:300
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:1358
int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
Generic read_packet() callback for subtitles demuxers using this queue system.
Definition: subtitles.c:211
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:1500
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:4502
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:241
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1598
#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:186
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:69
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3966
Definition: graph2dot.c:48
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:796
#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:811
static int subviewer_probe(const AVProbeData *p)
Definition: subviewerdec.c:40
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:530
Stream structure.
Definition: avformat.h:881
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:248
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:87
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
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:5747
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
static int read_ts(const char *s, int64_t *start, int *duration)
Definition: subviewerdec.c:54
#define flags(name, subs,...)
Definition: cbs_av1.c:561
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:1054
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
Main libavformat public API header.
common internal api header.
static int subviewer_read_header(AVFormatContext *s)
Definition: subviewerdec.c:70
AVInputFormat ff_subviewer_demuxer
Definition: subviewerdec.c:190
int len
static int subviewer_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: subviewerdec.c:169
void * priv_data
Format private data.
Definition: avformat.h:1386
static int subviewer_read_close(AVFormatContext *s)
Definition: subviewerdec.c:183
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: avcodec.h:3984
FFDemuxSubtitlesQueue q
Definition: subviewerdec.c:37
void INT64 start
Definition: avisynth_c.h:766
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:654
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:361
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: avcodec.h:1459
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:193
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1475
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248