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 "internal.h"
29 #include "subtitles.h"
30 #include "avio_internal.h"
31 #include "libavutil/avstring.h"
32 #include "libavutil/bprint.h"
33 #include "libavutil/intreadwrite.h"
34 
35 typedef struct {
38 
39 static int subviewer_probe(const AVProbeData *p)
40 {
41  char c;
42  const unsigned char *ptr = p->buf;
43 
44  if (AV_RB24(ptr) == 0xEFBBBF)
45  ptr += 3; /* skip UTF-8 BOM */
46  if (sscanf(ptr, "%*u:%*u:%*u.%*u,%*u:%*u:%*u.%*u%c", &c) == 1)
48  if (!strncmp(ptr, "[INFORMATION]", 13))
49  return AVPROBE_SCORE_MAX/3;
50  return 0;
51 }
52 
53 static int read_ts(const char *s, int64_t *start, int *duration)
54 {
55  int64_t end;
56  int hh1, mm1, ss1, ms1;
57  int hh2, mm2, ss2, ms2;
58  int multiplier = 1;
59 
60  if (sscanf(s, "%u:%u:%u.%2u,%u:%u:%u.%2u",
61  &hh1, &mm1, &ss1, &ms1, &hh2, &mm2, &ss2, &ms2) == 8) {
62  multiplier = 10;
63  } else if (sscanf(s, "%u:%u:%u.%1u,%u:%u:%u.%1u",
64  &hh1, &mm1, &ss1, &ms1, &hh2, &mm2, &ss2, &ms2) == 8) {
65  multiplier = 100;
66  }
67  if (sscanf(s, "%u:%u:%u.%u,%u:%u:%u.%u",
68  &hh1, &mm1, &ss1, &ms1, &hh2, &mm2, &ss2, &ms2) == 8) {
69  ms1 = FFMIN(ms1, 999);
70  ms2 = FFMIN(ms2, 999);
71  end = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2 * multiplier;
72  *start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1 * multiplier;
73  *duration = end - *start;
74  return 0;
75  }
76  return -1;
77 }
78 
80 {
81  SubViewerContext *subviewer = s->priv_data;
83  AVBPrint header;
84  int res = 0, new_event = 1;
85  int64_t pts_start = AV_NOPTS_VALUE;
86  int duration = -1;
87  AVPacket *sub = NULL;
88 
89  if (!st)
90  return AVERROR(ENOMEM);
91  res = ffio_ensure_seekback(s->pb, 3);
92  if (res < 0)
93  return res;
94  if (avio_rb24(s->pb) != 0xefbbbf)
95  avio_seek(s->pb, -3, SEEK_CUR);
96  avpriv_set_pts_info(st, 64, 1, 1000);
99 
101 
102  while (!avio_feof(s->pb)) {
103  char line[2048];
104  int64_t pos = 0;
105  int len = ff_get_line(s->pb, line, sizeof(line));
106 
107  if (!len)
108  break;
109 
110  line[strcspn(line, "\r\n")] = 0;
111 
112  if (line[0] == '[' && strncmp(line, "[br]", 4)) {
113 
114  /* ignore event style, XXX: add to side_data? */
115  if (strstr(line, "[COLF]") || strstr(line, "[SIZE]") ||
116  strstr(line, "[FONT]") || strstr(line, "[STYLE]"))
117  continue;
118 
119  if (!st->codecpar->extradata) { // header not finalized yet
120  av_bprintf(&header, "%s\n", line);
121  if (!strncmp(line, "[END INFORMATION]", 17) || !strncmp(line, "[SUBTITLE]", 10)) {
122  /* end of header */
124  if (res < 0)
125  goto end;
126  } else if (strncmp(line, "[INFORMATION]", 13)) {
127  /* assume file metadata at this point */
128  int i, j = 0;
129  char key[32], value[128];
130 
131  for (i = 1; i < sizeof(key) - 1 && line[i] && line[i] != ']'; i++)
132  key[i - 1] = av_tolower(line[i]);
133  key[i - 1] = 0;
134 
135  if (line[i] == ']')
136  i++;
137  while (line[i] == ' ')
138  i++;
139  while (j < sizeof(value) - 1 && line[i] && line[i] != ']')
140  value[j++] = line[i++];
141  value[j] = 0;
142 
143  av_dict_set(&s->metadata, key, value, 0);
144  }
145  }
146  } else if (read_ts(line, &pts_start, &duration) >= 0) {
147  new_event = 1;
148  pos = avio_tell(s->pb);
149  } else if (*line) {
150  if (pts_start == AV_NOPTS_VALUE) {
151  res = AVERROR_INVALIDDATA;
152  goto end;
153  }
154  if (!new_event) {
155  sub = ff_subtitles_queue_insert(&subviewer->q, "\n", 1, 1);
156  if (!sub) {
157  res = AVERROR(ENOMEM);
158  goto end;
159  }
160  }
161  sub = ff_subtitles_queue_insert(&subviewer->q, line, strlen(line), !new_event);
162  if (!sub) {
163  res = AVERROR(ENOMEM);
164  goto end;
165  }
166  if (new_event) {
167  sub->pos = pos;
168  sub->pts = pts_start;
169  sub->duration = duration;
170  }
171  new_event = 0;
172  }
173  }
174 
175  ff_subtitles_queue_finalize(s, &subviewer->q);
176 
177 end:
179  return res;
180 }
181 
183  .name = "subviewer",
184  .long_name = NULL_IF_CONFIG_SMALL("SubViewer subtitle format"),
185  .priv_data_size = sizeof(SubViewerContext),
186  .flags_internal = FF_FMT_INIT_CLEANUP,
189  .extensions = "sub",
191  .read_seek2 = ff_subtitles_read_seek,
193 };
AVMEDIA_TYPE_SUBTITLE
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
ff_subtitles_read_close
int ff_subtitles_read_close(AVFormatContext *s)
Definition: subtitles.c:329
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:75
FF_FMT_INIT_CLEANUP
#define FF_FMT_INIT_CLEANUP
For an AVInputFormat with this flag set read_close() needs to be called by the caller upon read_heade...
Definition: internal.h:48
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
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: options.c:237
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:57
av_bprint_finalize
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:235
av_bprint_init
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:69
sub
static float sub(float src0, float src1)
Definition: dnn_backend_native_layer_mathbinary.c:31
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:583
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:465
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:697
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:505
AV_CODEC_ID_SUBVIEWER
@ AV_CODEC_ID_SUBVIEWER
Definition: codec_id.h:543
AVInputFormat
Definition: avformat.h:656
ff_subtitles_read_packet
int ff_subtitles_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: subtitles.c:315
duration
int64_t duration
Definition: movenc.c:64
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:256
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:661
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:455
key
const char * key
Definition: hwcontext_opencl.c:174
AVFormatContext
Format I/O context.
Definition: avformat.h:1213
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1108
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:529
NULL
#define NULL
Definition: coverity.c:32
read_probe
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:453
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:463
avio_rb24
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:783
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:117
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:196
FFDemuxSubtitlesQueue
Definition: subtitles.h:103
header
static const uint8_t header[24]
Definition: sdr2.c:67
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:1055
line
Definition: graph2dot.c:48
subviewer_probe
static int subviewer_probe(const AVProbeData *p)
Definition: subviewerdec.c:39
SubViewerContext
Definition: subviewerdec.c:35
bprint.h
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
avio_internal.h
read_ts
static int read_ts(const char *s, int64_t *start, int *duration)
Definition: subviewerdec.c:53
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
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
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:321
ff_get_line
int ff_get_line(AVIOContext *s, char *buf, int maxlen)
Read a whole line of text from AVIOContext.
Definition: aviobuf.c:798
len
int len
Definition: vorbis_enc_data.h:426
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
AVStream
Stream structure.
Definition: avformat.h:948
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:260
pos
unsigned int pos
Definition: spdifenc.c:412
avformat.h
av_bprintf
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:94
subtitles.h
subviewer_read_header
static int subviewer_read_header(AVFormatContext *s)
Definition: subviewerdec.c:79
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:61
AVPacket
This structure stores compressed data.
Definition: packet.h:351
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:70
ff_subviewer_demuxer
const AVInputFormat ff_subviewer_demuxer
Definition: subviewerdec.c:182
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:36
av_tolower
static av_const int av_tolower(int c)
Locale-independent conversion of ASCII characters to lowercase.
Definition: avstring.h:246
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:375