FFmpeg  4.4.6
subtitles.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2012-2013 Clément Bœsch <u pkh me>
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 #include "avformat.h"
22 #include "subtitles.h"
23 #include "avio_internal.h"
24 #include "libavutil/avassert.h"
25 #include "libavutil/avstring.h"
26 
28 {
29  int i;
30  r->pb = pb;
31  r->buf_pos = r->buf_len = 0;
32  r->type = FF_UTF_8;
33  for (i = 0; i < 2; i++)
34  r->buf[r->buf_len++] = avio_r8(r->pb);
35  if (strncmp("\xFF\xFE", r->buf, 2) == 0) {
36  r->type = FF_UTF16LE;
37  r->buf_pos += 2;
38  } else if (strncmp("\xFE\xFF", r->buf, 2) == 0) {
39  r->type = FF_UTF16BE;
40  r->buf_pos += 2;
41  } else {
42  r->buf[r->buf_len++] = avio_r8(r->pb);
43  if (strncmp("\xEF\xBB\xBF", r->buf, 3) == 0) {
44  // UTF8
45  r->buf_pos += 3;
46  }
47  }
48  if (s && (r->type == FF_UTF16LE || r->type == FF_UTF16BE))
50  "UTF16 is automatically converted to UTF8, do not specify a character encoding\n");
51 }
52 
53 void ff_text_init_buf(FFTextReader *r, void *buf, size_t size)
54 {
55  memset(&r->buf_pb, 0, sizeof(r->buf_pb));
56  ffio_init_context(&r->buf_pb, buf, size, 0, NULL, NULL, NULL, NULL);
57  ff_text_init_avio(NULL, r, &r->buf_pb);
58 }
59 
61 {
62  return avio_tell(r->pb) - r->buf_len + r->buf_pos;
63 }
64 
66 {
67  uint32_t val;
68  uint8_t tmp;
69  if (r->buf_pos < r->buf_len)
70  return r->buf[r->buf_pos++];
71  if (r->type == FF_UTF16LE) {
72  GET_UTF16(val, avio_rl16(r->pb), return 0;)
73  } else if (r->type == FF_UTF16BE) {
74  GET_UTF16(val, avio_rb16(r->pb), return 0;)
75  } else {
76  return avio_r8(r->pb);
77  }
78  if (!val)
79  return 0;
80  r->buf_pos = 0;
81  r->buf_len = 0;
82  PUT_UTF8(val, tmp, r->buf[r->buf_len++] = tmp;)
83  return r->buf[r->buf_pos++]; // buf_len is at least 1
84 }
85 
86 void ff_text_read(FFTextReader *r, char *buf, size_t size)
87 {
88  for ( ; size > 0; size--)
89  *buf++ = ff_text_r8(r);
90 }
91 
93 {
94  return r->buf_pos >= r->buf_len && avio_feof(r->pb);
95 }
96 
98 {
99  int c;
100  if (r->buf_pos < r->buf_len)
101  return r->buf[r->buf_pos];
102  c = ff_text_r8(r);
103  if (!avio_feof(r->pb)) {
104  r->buf_pos = 0;
105  r->buf_len = 1;
106  r->buf[0] = c;
107  }
108  return c;
109 }
110 
112  const uint8_t *event, size_t len, int merge)
113 {
114  AVPacket **subs, *sub;
115 
116  if (merge && q->nb_subs > 0) {
117  /* merge with previous event */
118 
119  int old_len;
120  sub = q->subs[q->nb_subs - 1];
121  old_len = sub->size;
122  if (av_grow_packet(sub, len) < 0)
123  return NULL;
124  memcpy(sub->data + old_len, event, len);
125  } else {
126  /* new event */
127 
128  if (q->nb_subs >= INT_MAX/sizeof(*q->subs) - 1)
129  return NULL;
130  subs = av_fast_realloc(q->subs, &q->allocated_size,
131  (q->nb_subs + 1) * sizeof(*q->subs));
132  if (!subs)
133  return NULL;
134  q->subs = subs;
135  sub = av_packet_alloc();
136  if (!sub)
137  return NULL;
138  if (av_new_packet(sub, len) < 0) {
140  return NULL;
141  }
142  subs[q->nb_subs++] = sub;
143  sub->flags |= AV_PKT_FLAG_KEY;
144  sub->pts = sub->dts = 0;
145  memcpy(sub->data, event, len);
146  }
147  return sub;
148 }
149 
150 static int cmp_pkt_sub_ts_pos(const void *a, const void *b)
151 {
152  const AVPacket *s1 = *(const AVPacket **)a;
153  const AVPacket *s2 = *(const AVPacket **)b;
154  if (s1->pts == s2->pts)
155  return FFDIFFSIGN(s1->pos, s2->pos);
156  return FFDIFFSIGN(s1->pts , s2->pts);
157 }
158 
159 static int cmp_pkt_sub_pos_ts(const void *a, const void *b)
160 {
161  const AVPacket *s1 = *(const AVPacket **)a;
162  const AVPacket *s2 = *(const AVPacket **)b;
163  if (s1->pos == s2->pos) {
164  if (s1->pts == s2->pts)
165  return 0;
166  return s1->pts > s2->pts ? 1 : -1;
167  }
168  return s1->pos > s2->pos ? 1 : -1;
169 }
170 
171 static void drop_dups(void *log_ctx, FFDemuxSubtitlesQueue *q)
172 {
173  int i, drop = 0;
174 
175  for (i = 1; i < q->nb_subs; i++) {
176  const int last_id = i - 1 - drop;
177  const AVPacket *last = q->subs[last_id];
178 
179  if (q->subs[i]->pts == last->pts &&
180  q->subs[i]->duration == last->duration &&
181  q->subs[i]->stream_index == last->stream_index &&
182  !strcmp(q->subs[i]->data, last->data)) {
183 
184  av_packet_free(&q->subs[i]);
185  drop++;
186  } else if (drop) {
187  q->subs[last_id + 1] = q->subs[i];
188  q->subs[i] = NULL;
189  }
190  }
191 
192  if (drop) {
193  q->nb_subs -= drop;
194  av_log(log_ctx, AV_LOG_WARNING, "Dropping %d duplicated subtitle events\n", drop);
195  }
196 }
197 
199 {
200  int i;
201 
202  if (!q->nb_subs)
203  return;
204 
205  qsort(q->subs, q->nb_subs, sizeof(*q->subs),
208  for (i = 0; i < q->nb_subs; i++)
209  if (q->subs[i]->duration < 0 && i < q->nb_subs - 1 && q->subs[i + 1]->pts - (uint64_t)q->subs[i]->pts <= INT64_MAX)
210  q->subs[i]->duration = q->subs[i + 1]->pts - q->subs[i]->pts;
211 
212  if (!q->keep_duplicates)
213  drop_dups(log_ctx, q);
214 }
215 
217 {
218  AVPacket *sub;
219  int ret;
220 
221  if (q->current_sub_idx == q->nb_subs)
222  return AVERROR_EOF;
223  sub = q->subs[q->current_sub_idx];
224  if ((ret = av_packet_ref(pkt, sub)) < 0) {
225  return ret;
226  }
227 
228  pkt->dts = pkt->pts;
229  q->current_sub_idx++;
230  return 0;
231 }
232 
234 {
235  int s1 = 0, s2 = q->nb_subs - 1;
236 
237  if (s2 < s1)
238  return AVERROR(ERANGE);
239 
240  for (;;) {
241  int mid;
242 
243  if (s1 == s2)
244  return s1;
245  if (s1 == s2 - 1)
246  return q->subs[s1]->pts <= q->subs[s2]->pts ? s1 : s2;
247  mid = (s1 + s2) / 2;
248  if (q->subs[mid]->pts <= ts)
249  s1 = mid;
250  else
251  s2 = mid;
252  }
253 }
254 
256  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
257 {
258  if (flags & AVSEEK_FLAG_BYTE) {
259  return AVERROR(ENOSYS);
260  } else if (flags & AVSEEK_FLAG_FRAME) {
261  if (ts < 0 || ts >= q->nb_subs)
262  return AVERROR(ERANGE);
263  q->current_sub_idx = ts;
264  } else {
265  int i, idx = search_sub_ts(q, ts);
266  int64_t ts_selected;
267 
268  if (idx < 0)
269  return idx;
270  for (i = idx; i < q->nb_subs && q->subs[i]->pts < min_ts; i++)
271  if (stream_index == -1 || q->subs[i]->stream_index == stream_index)
272  idx = i;
273  for (i = idx; i > 0 && q->subs[i]->pts > max_ts; i--)
274  if (stream_index == -1 || q->subs[i]->stream_index == stream_index)
275  idx = i;
276 
277  ts_selected = q->subs[idx]->pts;
278  if (ts_selected < min_ts || ts_selected > max_ts)
279  return AVERROR(ERANGE);
280 
281  /* look back in the latest subtitles for overlapping subtitles */
282  for (i = idx - 1; i >= 0; i--) {
283  int64_t pts = q->subs[i]->pts;
284  if (q->subs[i]->duration <= 0 ||
285  (stream_index != -1 && q->subs[i]->stream_index != stream_index))
286  continue;
287  if (pts >= min_ts && pts > ts_selected - q->subs[i]->duration)
288  idx = i;
289  else
290  break;
291  }
292 
293  /* If the queue is used to store multiple subtitles streams (like with
294  * VobSub) and the stream index is not specified, we need to make sure
295  * to focus on the smallest file position offset for a same timestamp;
296  * queue is ordered by pts and then filepos, so we can take the first
297  * entry for a given timestamp. */
298  if (stream_index == -1)
299  while (idx > 0 && q->subs[idx - 1]->pts == q->subs[idx]->pts)
300  idx--;
301 
302  q->current_sub_idx = idx;
303  }
304  return 0;
305 }
306 
308 {
309  int i;
310 
311  for (i = 0; i < q->nb_subs; i++)
312  av_packet_free(&q->subs[i]);
313  av_freep(&q->subs);
314  q->nb_subs = q->allocated_size = q->current_sub_idx = 0;
315 }
316 
317 int ff_smil_extract_next_text_chunk(FFTextReader *tr, AVBPrint *buf, char *c)
318 {
319  int i = 0;
320  char end_chr;
321 
322  if (!*c) // cached char?
323  *c = ff_text_r8(tr);
324  if (!*c)
325  return 0;
326 
327  end_chr = *c == '<' ? '>' : '<';
328  do {
329  av_bprint_chars(buf, *c, 1);
330  *c = ff_text_r8(tr);
331  i++;
332  } while (*c != end_chr && *c);
333  if (end_chr == '>') {
334  av_bprint_chars(buf, '>', 1);
335  *c = 0;
336  }
337  return i;
338 }
339 
340 const char *ff_smil_get_attr_ptr(const char *s, const char *attr)
341 {
342  int in_quotes = 0;
343  const size_t len = strlen(attr);
344 
345  while (*s) {
346  while (*s) {
347  if (!in_quotes && av_isspace(*s))
348  break;
349  in_quotes ^= *s == '"'; // XXX: support escaping?
350  s++;
351  }
352  while (av_isspace(*s))
353  s++;
354  if (!av_strncasecmp(s, attr, len) && s[len] == '=')
355  return s + len + 1 + (s[len + 1] == '"');
356  }
357  return NULL;
358 }
359 
360 static inline int is_eol(char c)
361 {
362  return c == '\r' || c == '\n';
363 }
364 
366 {
367  char eol_buf[5], last_was_cr = 0;
368  int n = 0, i = 0, nb_eol = 0;
369 
370  av_bprint_clear(buf);
371 
372  for (;;) {
373  char c = ff_text_r8(tr);
374 
375  if (!c)
376  break;
377 
378  /* ignore all initial line breaks */
379  if (n == 0 && is_eol(c))
380  continue;
381 
382  /* line break buffering: we don't want to add the trailing \r\n */
383  if (is_eol(c)) {
384  nb_eol += c == '\n' || last_was_cr;
385  if (nb_eol == 2)
386  break;
387  eol_buf[i++] = c;
388  if (i == sizeof(eol_buf) - 1)
389  break;
390  last_was_cr = c == '\r';
391  continue;
392  }
393 
394  /* only one line break followed by data: we flush the line breaks
395  * buffer */
396  if (i) {
397  eol_buf[i] = 0;
398  av_bprintf(buf, "%s", eol_buf);
399  i = nb_eol = 0;
400  }
401 
402  av_bprint_chars(buf, c, 1);
403  n++;
404  }
405 }
406 
407 void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
408 {
409  FFTextReader tr;
410  tr.buf_pos = tr.buf_len = 0;
411  tr.type = 0;
412  tr.pb = pb;
414 }
415 
416 ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size)
417 {
418  size_t cur = 0;
419  if (!size)
420  return 0;
421  buf[0] = '\0';
422  while (cur + 1 < size) {
423  unsigned char c = ff_text_r8(tr);
424  if (!c)
425  return ff_text_eof(tr) ? cur : AVERROR_INVALIDDATA;
426  if (c == '\r' || c == '\n')
427  break;
428  buf[cur++] = c;
429  buf[cur] = '\0';
430  }
431  while (ff_text_peek_r8(tr) == '\r')
432  ff_text_r8(tr);
433  if (ff_text_peek_r8(tr) == '\n')
434  ff_text_r8(tr);
435  return cur;
436 }
static double val(void *priv, double ch)
Definition: aeval.c:76
uint8_t
simple assert() macros that are a bit more flexible than ISO C assert().
Main libavformat public API header.
#define AVSEEK_FLAG_BYTE
seeking based on position in bytes
Definition: avformat.h:2416
#define AVSEEK_FLAG_FRAME
seeking based on frame number
Definition: avformat.h:2418
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:766
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:364
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:734
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:624
int ffio_init_context(AVIOContext *s, unsigned char *buffer, int buffer_size, int write_flag, void *opaque, int(*read_packet)(void *opaque, uint8_t *buf, int buf_size), int(*write_packet)(void *opaque, uint8_t *buf, int buf_size), int64_t(*seek)(void *opaque, int64_t offset, int whence))
Definition: aviobuf.c:88
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:94
void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
Append char c n times to a print buffer.
Definition: bprint.c:140
void av_bprint_clear(AVBPrint *buf)
Reset the string to "" but keep internal allocated data.
Definition: bprint.c:227
#define flags(name, subs,...)
Definition: cbs_av1.c:572
#define s(width, name)
Definition: cbs_vp9.c:257
#define GET_UTF16(val, GET_16BIT, ERROR)
Convert a UTF-16 character (2 or 4 bytes) to its 32-bit UCS-4 encoded form.
Definition: common.h:524
#define PUT_UTF8(val, tmp, PUT_BYTE)
Convert a 32-bit Unicode character to its UTF-8 encoded form (up to 4 bytes long).
Definition: common.h:552
#define FFDIFFSIGN(x, y)
Comparator.
Definition: common.h:101
#define NULL
Definition: coverity.c:32
long long int64_t
Definition: coverity.c:34
static float sub(float src0, float src1)
void av_packet_free(AVPacket **pkt)
Free the packet, if the packet is reference counted, it will be unreferenced first.
Definition: avpacket.c:75
int av_grow_packet(AVPacket *pkt, int grow_by)
Increase packet size, correctly zeroing padding.
Definition: avpacket.c:122
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:410
AVPacket * av_packet_alloc(void)
Allocate an AVPacket and set its fields to default values.
Definition: avpacket.c:64
int av_packet_ref(AVPacket *dst, const AVPacket *src)
Setup a new reference to the data described by a given packet.
Definition: avpacket.c:641
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:99
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define AVERROR(e)
Definition: error.h:43
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:200
#define AV_LOG_INFO
Standard information.
Definition: log.h:205
void * av_fast_realloc(void *ptr, unsigned int *size, size_t min_size)
Reallocate the given buffer if it is not large enough, otherwise do nothing.
Definition: mem.c:478
static av_const int av_isspace(int c)
Locale-independent conversion of ASCII isspace.
Definition: avstring.h:227
int av_strncasecmp(const char *a, const char *b, size_t n)
Locale-independent case-insensitive compare.
Definition: avstring.c:225
int i
Definition: input.c:407
static void merge(GetBitContext *gb, uint8_t *dst, uint8_t *src, int size)
Merge two consequent lists of equal size depending on bits read.
Definition: bink.c:219
#define s1
Definition: regdef.h:38
#define s2
Definition: regdef.h:39
Format I/O context.
Definition: avformat.h:1232
Bytestream IO Context.
Definition: avio.h:161
This structure stores compressed data.
Definition: packet.h:346
int stream_index
Definition: packet.h:371
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:387
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:362
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed.
Definition: packet.h:368
uint8_t * data
Definition: packet.h:369
int nb_subs
number of subtitles packets
Definition: subtitles.h:104
AVPacket ** subs
array of subtitles packets
Definition: subtitles.h:103
int allocated_size
allocated size for subs
Definition: subtitles.h:105
int current_sub_idx
current position for the read packet callback
Definition: subtitles.h:106
enum sub_sort sort
sort method to use when finalizing subtitles
Definition: subtitles.h:107
int keep_duplicates
set to 1 to keep duplicated subtitle events
Definition: subtitles.h:108
AVIOContext * pb
Definition: subtitles.h:42
ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size)
Read a line of text.
Definition: subtitles.c:416
int64_t ff_text_pos(FFTextReader *r)
Return the byte position of the next byte returned by ff_text_r8().
Definition: subtitles.c:60
void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
Same as ff_subtitles_read_text_chunk(), but read from an AVIOContext.
Definition: subtitles.c:407
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:255
void ff_text_read(FFTextReader *r, char *buf, size_t size)
Read the given number of bytes (in UTF-8).
Definition: subtitles.c:86
void ff_text_init_buf(FFTextReader *r, void *buf, size_t size)
Similar to ff_text_init_avio(), but sets it up to read from a bounded buffer.
Definition: subtitles.c:53
static int cmp_pkt_sub_ts_pos(const void *a, const void *b)
Definition: subtitles.c:150
int ff_text_eof(FFTextReader *r)
Return non-zero if EOF was reached.
Definition: subtitles.c:92
static int is_eol(char c)
Definition: subtitles.c:360
static void drop_dups(void *log_ctx, FFDemuxSubtitlesQueue *q)
Definition: subtitles.c:171
static int search_sub_ts(const FFDemuxSubtitlesQueue *q, int64_t ts)
Definition: subtitles.c:233
void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb)
Initialize the FFTextReader from the given AVIOContext.
Definition: subtitles.c:27
int ff_text_r8(FFTextReader *r)
Return the next byte.
Definition: subtitles.c:65
int ff_smil_extract_next_text_chunk(FFTextReader *tr, AVBPrint *buf, char *c)
SMIL helper to load next chunk ("<...>" or untagged content) in buf.
Definition: subtitles.c:317
static int cmp_pkt_sub_pos_ts(const void *a, const void *b)
Definition: subtitles.c:159
int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
Generic read_packet() callback for subtitles demuxers using this queue system.
Definition: subtitles.c:216
int ff_text_peek_r8(FFTextReader *r)
Like ff_text_r8(), but don't remove the byte from the buffer.
Definition: subtitles.c:97
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:198
void ff_subtitles_read_text_chunk(FFTextReader *tr, AVBPrint *buf)
Read a subtitles chunk from FFTextReader.
Definition: subtitles.c:365
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:307
const char * ff_smil_get_attr_ptr(const char *s, const char *attr)
SMIL helper to point on the value of an attribute in the given tag.
Definition: subtitles.c:340
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
@ FF_UTF16LE
Definition: subtitles.h:36
@ FF_UTF_8
Definition: subtitles.h:35
@ FF_UTF16BE
Definition: subtitles.h:37
@ SUB_SORT_TS_POS
sort by timestamps, then position
Definition: subtitles.h:30
#define av_freep(p)
#define av_log(a,...)
static uint8_t tmp[11]
Definition: aes_ctr.c:27
AVPacket * pkt
Definition: movenc.c:59
static int64_t pts
int size
const char * b
Definition: vf_curves.c:118
const char * r
Definition: vf_curves.c:116
int len
static double c[64]