FFmpeg  4.2.2
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 "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:1497
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:4886
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3957
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
#define AV_RB24
Definition: intreadwrite.h:64
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:1495
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4459
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 AVERROR(e)
Definition: error.h:43
#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:3953
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:793
#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:808
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
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
double value
Definition: eval.c:98
int ff_bprint_to_codecpar_extradata(AVCodecParameters *par, struct AVBPrint *buf)
Finalize buf into extradata and set its size appropriately.
Definition: utils.c:5704
#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:1051
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
Main libavformat public API header.
common internal api header.
static double c[64]
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:3971
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:358
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
This structure stores compressed data.
Definition: avcodec.h:1454
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:1470
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248