FFmpeg
avio.c
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1 /*
2  * unbuffered I/O
3  * Copyright (c) 2001 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavutil/avstring.h"
23 #include "libavutil/dict.h"
24 #include "libavutil/opt.h"
25 #include "libavutil/time.h"
26 #include "libavutil/avassert.h"
27 #include "os_support.h"
28 #include "avformat.h"
29 #if CONFIG_NETWORK
30 #include "network.h"
31 #endif
32 #include "url.h"
33 
34 /** @name Logging context. */
35 /*@{*/
36 static const char *urlcontext_to_name(void *ptr)
37 {
38  URLContext *h = (URLContext *)ptr;
39  if (h->prot)
40  return h->prot->name;
41  else
42  return "NULL";
43 }
44 
45 static void *urlcontext_child_next(void *obj, void *prev)
46 {
47  URLContext *h = obj;
48  if (!prev && h->priv_data && h->prot->priv_data_class)
49  return h->priv_data;
50  return NULL;
51 }
52 
53 #define OFFSET(x) offsetof(URLContext,x)
54 #define E AV_OPT_FLAG_ENCODING_PARAM
55 #define D AV_OPT_FLAG_DECODING_PARAM
56 static const AVOption options[] = {
57  {"protocol_whitelist", "List of protocols that are allowed to be used", OFFSET(protocol_whitelist), AV_OPT_TYPE_STRING, { .str = NULL }, CHAR_MIN, CHAR_MAX, D },
58  {"protocol_blacklist", "List of protocols that are not allowed to be used", OFFSET(protocol_blacklist), AV_OPT_TYPE_STRING, { .str = NULL }, CHAR_MIN, CHAR_MAX, D },
59  {"rw_timeout", "Timeout for IO operations (in microseconds)", offsetof(URLContext, rw_timeout), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, AV_OPT_FLAG_ENCODING_PARAM | AV_OPT_FLAG_DECODING_PARAM },
60  { NULL }
61 };
62 
63 const AVClass ffurl_context_class = {
64  .class_name = "URLContext",
65  .item_name = urlcontext_to_name,
66  .option = options,
67  .version = LIBAVUTIL_VERSION_INT,
68  .child_next = urlcontext_child_next,
69  .child_class_next = ff_urlcontext_child_class_next,
70 };
71 /*@}*/
72 
73 static int url_alloc_for_protocol(URLContext **puc, const URLProtocol *up,
74  const char *filename, int flags,
75  const AVIOInterruptCB *int_cb)
76 {
77  URLContext *uc;
78  int err;
79 
80 #if CONFIG_NETWORK
81  if (up->flags & URL_PROTOCOL_FLAG_NETWORK && !ff_network_init())
82  return AVERROR(EIO);
83 #endif
84  if ((flags & AVIO_FLAG_READ) && !up->url_read) {
85  av_log(NULL, AV_LOG_ERROR,
86  "Impossible to open the '%s' protocol for reading\n", up->name);
87  return AVERROR(EIO);
88  }
89  if ((flags & AVIO_FLAG_WRITE) && !up->url_write) {
90  av_log(NULL, AV_LOG_ERROR,
91  "Impossible to open the '%s' protocol for writing\n", up->name);
92  return AVERROR(EIO);
93  }
94  uc = av_mallocz(sizeof(URLContext) + strlen(filename) + 1);
95  if (!uc) {
96  err = AVERROR(ENOMEM);
97  goto fail;
98  }
99  uc->av_class = &ffurl_context_class;
100  uc->filename = (char *)&uc[1];
101  strcpy(uc->filename, filename);
102  uc->prot = up;
103  uc->flags = flags;
104  uc->is_streamed = 0; /* default = not streamed */
105  uc->max_packet_size = 0; /* default: stream file */
106  if (up->priv_data_size) {
107  uc->priv_data = av_mallocz(up->priv_data_size);
108  if (!uc->priv_data) {
109  err = AVERROR(ENOMEM);
110  goto fail;
111  }
112  if (up->priv_data_class) {
113  int proto_len= strlen(up->name);
114  char *start = strchr(uc->filename, ',');
115  *(const AVClass **)uc->priv_data = up->priv_data_class;
116  av_opt_set_defaults(uc->priv_data);
117  if(!strncmp(up->name, uc->filename, proto_len) && uc->filename + proto_len == start){
118  int ret= 0;
119  char *p= start;
120  char sep= *++p;
121  char *key, *val;
122  p++;
123 
124  if (strcmp(up->name, "subfile"))
125  ret = AVERROR(EINVAL);
126 
127  while(ret >= 0 && (key= strchr(p, sep)) && p<key && (val = strchr(key+1, sep))){
128  *val= *key= 0;
129  if (strcmp(p, "start") && strcmp(p, "end")) {
130  ret = AVERROR_OPTION_NOT_FOUND;
131  } else
132  ret= av_opt_set(uc->priv_data, p, key+1, 0);
133  if (ret == AVERROR_OPTION_NOT_FOUND)
134  av_log(uc, AV_LOG_ERROR, "Key '%s' not found.\n", p);
135  *val= *key= sep;
136  p= val+1;
137  }
138  if(ret<0 || p!=key){
139  av_log(uc, AV_LOG_ERROR, "Error parsing options string %s\n", start);
140  av_freep(&uc->priv_data);
141  av_freep(&uc);
142  err = AVERROR(EINVAL);
143  goto fail;
144  }
145  memmove(start, key+1, strlen(key));
146  }
147  }
148  }
149  if (int_cb)
150  uc->interrupt_callback = *int_cb;
151 
152  *puc = uc;
153  return 0;
154 fail:
155  *puc = NULL;
156  if (uc)
157  av_freep(&uc->priv_data);
158  av_freep(&uc);
159 #if CONFIG_NETWORK
160  if (up->flags & URL_PROTOCOL_FLAG_NETWORK)
161  ff_network_close();
162 #endif
163  return err;
164 }
165 
166 int ffurl_connect(URLContext *uc, AVDictionary **options)
167 {
168  int err;
169  AVDictionary *tmp_opts = NULL;
170  AVDictionaryEntry *e;
171 
172  if (!options)
173  options = &tmp_opts;
174 
175  // Check that URLContext was initialized correctly and lists are matching if set
176  av_assert0(!(e=av_dict_get(*options, "protocol_whitelist", NULL, 0)) ||
177  (uc->protocol_whitelist && !strcmp(uc->protocol_whitelist, e->value)));
178  av_assert0(!(e=av_dict_get(*options, "protocol_blacklist", NULL, 0)) ||
179  (uc->protocol_blacklist && !strcmp(uc->protocol_blacklist, e->value)));
180 
181  if (uc->protocol_whitelist && av_match_list(uc->prot->name, uc->protocol_whitelist, ',') <= 0) {
182  av_log(uc, AV_LOG_ERROR, "Protocol '%s' not on whitelist '%s'!\n", uc->prot->name, uc->protocol_whitelist);
183  return AVERROR(EINVAL);
184  }
185 
186  if (uc->protocol_blacklist && av_match_list(uc->prot->name, uc->protocol_blacklist, ',') > 0) {
187  av_log(uc, AV_LOG_ERROR, "Protocol '%s' on blacklist '%s'!\n", uc->prot->name, uc->protocol_blacklist);
188  return AVERROR(EINVAL);
189  }
190 
191  if (!uc->protocol_whitelist && uc->prot->default_whitelist) {
192  av_log(uc, AV_LOG_DEBUG, "Setting default whitelist '%s'\n", uc->prot->default_whitelist);
193  uc->protocol_whitelist = av_strdup(uc->prot->default_whitelist);
194  if (!uc->protocol_whitelist) {
195  return AVERROR(ENOMEM);
196  }
197  } else if (!uc->protocol_whitelist)
198  av_log(uc, AV_LOG_DEBUG, "No default whitelist set\n"); // This should be an error once all declare a default whitelist
199 
200  if ((err = av_dict_set(options, "protocol_whitelist", uc->protocol_whitelist, 0)) < 0)
201  return err;
202  if ((err = av_dict_set(options, "protocol_blacklist", uc->protocol_blacklist, 0)) < 0)
203  return err;
204 
205  err =
206  uc->prot->url_open2 ? uc->prot->url_open2(uc,
207  uc->filename,
208  uc->flags,
209  options) :
210  uc->prot->url_open(uc, uc->filename, uc->flags);
211 
212  av_dict_set(options, "protocol_whitelist", NULL, 0);
213  av_dict_set(options, "protocol_blacklist", NULL, 0);
214 
215  if (err)
216  return err;
217  uc->is_connected = 1;
218  /* We must be careful here as ffurl_seek() could be slow,
219  * for example for http */
220  if ((uc->flags & AVIO_FLAG_WRITE) || !strcmp(uc->prot->name, "file"))
221  if (!uc->is_streamed && ffurl_seek(uc, 0, SEEK_SET) < 0)
222  uc->is_streamed = 1;
223  return 0;
224 }
225 
226 int ffurl_accept(URLContext *s, URLContext **c)
227 {
228  av_assert0(!*c);
229  if (s->prot->url_accept)
230  return s->prot->url_accept(s, c);
231  return AVERROR(EBADF);
232 }
233 
234 int ffurl_handshake(URLContext *c)
235 {
236  int ret;
237  if (c->prot->url_handshake) {
238  ret = c->prot->url_handshake(c);
239  if (ret)
240  return ret;
241  }
242  c->is_connected = 1;
243  return 0;
244 }
245 
246 #define URL_SCHEME_CHARS \
247  "abcdefghijklmnopqrstuvwxyz" \
248  "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
249  "0123456789+-."
250 
251 static const struct URLProtocol *url_find_protocol(const char *filename)
252 {
253  const URLProtocol **protocols;
254  char proto_str[128], proto_nested[128], *ptr;
255  size_t proto_len = strspn(filename, URL_SCHEME_CHARS);
256  int i;
257 
258  if (filename[proto_len] != ':' &&
259  (strncmp(filename, "subfile,", 8) || !strchr(filename + proto_len + 1, ':')) ||
260  is_dos_path(filename))
261  strcpy(proto_str, "file");
262  else
263  av_strlcpy(proto_str, filename,
264  FFMIN(proto_len + 1, sizeof(proto_str)));
265 
266  av_strlcpy(proto_nested, proto_str, sizeof(proto_nested));
267  if ((ptr = strchr(proto_nested, '+')))
268  *ptr = '\0';
269 
270  protocols = ffurl_get_protocols(NULL, NULL);
271  if (!protocols)
272  return NULL;
273  for (i = 0; protocols[i]; i++) {
274  const URLProtocol *up = protocols[i];
275  if (!strcmp(proto_str, up->name)) {
276  av_freep(&protocols);
277  return up;
278  }
279  if (up->flags & URL_PROTOCOL_FLAG_NESTED_SCHEME &&
280  !strcmp(proto_nested, up->name)) {
281  av_freep(&protocols);
282  return up;
283  }
284  }
285  av_freep(&protocols);
286 
287  return NULL;
288 }
289 
290 int ffurl_alloc(URLContext **puc, const char *filename, int flags,
291  const AVIOInterruptCB *int_cb)
292 {
293  const URLProtocol *p = NULL;
294 
295  p = url_find_protocol(filename);
296  if (p)
297  return url_alloc_for_protocol(puc, p, filename, flags, int_cb);
298 
299  *puc = NULL;
300  if (av_strstart(filename, "https:", NULL) || av_strstart(filename, "tls:", NULL))
301  av_log(NULL, AV_LOG_WARNING, "https protocol not found, recompile FFmpeg with "
302  "openssl, gnutls "
303  "or securetransport enabled.\n");
304  return AVERROR_PROTOCOL_NOT_FOUND;
305 }
306 
307 int ffurl_open_whitelist(URLContext **puc, const char *filename, int flags,
308  const AVIOInterruptCB *int_cb, AVDictionary **options,
309  const char *whitelist, const char* blacklist,
310  URLContext *parent)
311 {
312  AVDictionary *tmp_opts = NULL;
313  AVDictionaryEntry *e;
314  int ret = ffurl_alloc(puc, filename, flags, int_cb);
315  if (ret < 0)
316  return ret;
317  if (parent) {
318  ret = av_opt_copy(*puc, parent);
319  if (ret < 0)
320  goto fail;
321  }
322  if (options &&
323  (ret = av_opt_set_dict(*puc, options)) < 0)
324  goto fail;
325  if (options && (*puc)->prot->priv_data_class &&
326  (ret = av_opt_set_dict((*puc)->priv_data, options)) < 0)
327  goto fail;
328 
329  if (!options)
330  options = &tmp_opts;
331 
332  av_assert0(!whitelist ||
333  !(e=av_dict_get(*options, "protocol_whitelist", NULL, 0)) ||
334  !strcmp(whitelist, e->value));
335  av_assert0(!blacklist ||
336  !(e=av_dict_get(*options, "protocol_blacklist", NULL, 0)) ||
337  !strcmp(blacklist, e->value));
338 
339  if ((ret = av_dict_set(options, "protocol_whitelist", whitelist, 0)) < 0)
340  goto fail;
341 
342  if ((ret = av_dict_set(options, "protocol_blacklist", blacklist, 0)) < 0)
343  goto fail;
344 
345  if ((ret = av_opt_set_dict(*puc, options)) < 0)
346  goto fail;
347 
348  ret = ffurl_connect(*puc, options);
349 
350  if (!ret)
351  return 0;
352 fail:
353  ffurl_close(*puc);
354  *puc = NULL;
355  return ret;
356 }
357 
358 int ffurl_open(URLContext **puc, const char *filename, int flags,
359  const AVIOInterruptCB *int_cb, AVDictionary **options)
360 {
361  return ffurl_open_whitelist(puc, filename, flags,
362  int_cb, options, NULL, NULL, NULL);
363 }
364 
365 static inline int retry_transfer_wrapper(URLContext *h, uint8_t *buf,
366  int size, int size_min,
367  int (*transfer_func)(URLContext *h,
368  uint8_t *buf,
369  int size))
370 {
371  int ret, len;
372  int fast_retries = 5;
373  int64_t wait_since = 0;
374 
375  len = 0;
376  while (len < size_min) {
377  if (ff_check_interrupt(&h->interrupt_callback))
378  return AVERROR_EXIT;
379  ret = transfer_func(h, buf + len, size - len);
380  if (ret == AVERROR(EINTR))
381  continue;
382  if (h->flags & AVIO_FLAG_NONBLOCK)
383  return ret;
384  if (ret == AVERROR(EAGAIN)) {
385  ret = 0;
386  if (fast_retries) {
387  fast_retries--;
388  } else {
389  if (h->rw_timeout) {
390  if (!wait_since)
391  wait_since = av_gettime_relative();
392  else if (av_gettime_relative() > wait_since + h->rw_timeout)
393  return AVERROR(EIO);
394  }
395  av_usleep(1000);
396  }
397  } else if (ret == AVERROR_EOF)
398  return (len > 0) ? len : AVERROR_EOF;
399  else if (ret < 0)
400  return ret;
401  if (ret) {
402  fast_retries = FFMAX(fast_retries, 2);
403  wait_since = 0;
404  }
405  len += ret;
406  }
407  return len;
408 }
409 
410 int ffurl_read(URLContext *h, unsigned char *buf, int size)
411 {
412  if (!(h->flags & AVIO_FLAG_READ))
413  return AVERROR(EIO);
414  return retry_transfer_wrapper(h, buf, size, 1, h->prot->url_read);
415 }
416 
417 int ffurl_read_complete(URLContext *h, unsigned char *buf, int size)
418 {
419  if (!(h->flags & AVIO_FLAG_READ))
420  return AVERROR(EIO);
421  return retry_transfer_wrapper(h, buf, size, size, h->prot->url_read);
422 }
423 
424 int ffurl_write(URLContext *h, const unsigned char *buf, int size)
425 {
426  if (!(h->flags & AVIO_FLAG_WRITE))
427  return AVERROR(EIO);
428  /* avoid sending too big packets */
429  if (h->max_packet_size && size > h->max_packet_size)
430  return AVERROR(EIO);
431 
432  return retry_transfer_wrapper(h, (unsigned char *)buf, size, size,
433  (int (*)(struct URLContext *, uint8_t *, int))
434  h->prot->url_write);
435 }
436 
437 int64_t ffurl_seek(URLContext *h, int64_t pos, int whence)
438 {
439  int64_t ret;
440 
441  if (!h->prot->url_seek)
442  return AVERROR(ENOSYS);
443  ret = h->prot->url_seek(h, pos, whence & ~AVSEEK_FORCE);
444  return ret;
445 }
446 
447 int ffurl_closep(URLContext **hh)
448 {
449  URLContext *h= *hh;
450  int ret = 0;
451  if (!h)
452  return 0; /* can happen when ffurl_open fails */
453 
454  if (h->is_connected && h->prot->url_close)
455  ret = h->prot->url_close(h);
456 #if CONFIG_NETWORK
457  if (h->prot->flags & URL_PROTOCOL_FLAG_NETWORK)
458  ff_network_close();
459 #endif
460  if (h->prot->priv_data_size) {
461  if (h->prot->priv_data_class)
462  av_opt_free(h->priv_data);
463  av_freep(&h->priv_data);
464  }
465  av_opt_free(h);
466  av_freep(hh);
467  return ret;
468 }
469 
470 int ffurl_close(URLContext *h)
471 {
472  return ffurl_closep(&h);
473 }
474 
475 
476 const char *avio_find_protocol_name(const char *url)
477 {
478  const URLProtocol *p = url_find_protocol(url);
479 
480  return p ? p->name : NULL;
481 }
482 
483 int avio_check(const char *url, int flags)
484 {
485  URLContext *h;
486  int ret = ffurl_alloc(&h, url, flags, NULL);
487  if (ret < 0)
488  return ret;
489 
490  if (h->prot->url_check) {
491  ret = h->prot->url_check(h, flags);
492  } else {
493  ret = ffurl_connect(h, NULL);
494  if (ret >= 0)
495  ret = flags;
496  }
497 
498  ffurl_close(h);
499  return ret;
500 }
501 
502 int avpriv_io_move(const char *url_src, const char *url_dst)
503 {
504  URLContext *h_src, *h_dst;
505  int ret = ffurl_alloc(&h_src, url_src, AVIO_FLAG_READ_WRITE, NULL);
506  if (ret < 0)
507  return ret;
508  ret = ffurl_alloc(&h_dst, url_dst, AVIO_FLAG_WRITE, NULL);
509  if (ret < 0) {
510  ffurl_close(h_src);
511  return ret;
512  }
513 
514  if (h_src->prot == h_dst->prot && h_src->prot->url_move)
515  ret = h_src->prot->url_move(h_src, h_dst);
516  else
517  ret = AVERROR(ENOSYS);
518 
519  ffurl_close(h_src);
520  ffurl_close(h_dst);
521  return ret;
522 }
523 
524 int avpriv_io_delete(const char *url)
525 {
526  URLContext *h;
527  int ret = ffurl_alloc(&h, url, AVIO_FLAG_WRITE, NULL);
528  if (ret < 0)
529  return ret;
530 
531  if (h->prot->url_delete)
532  ret = h->prot->url_delete(h);
533  else
534  ret = AVERROR(ENOSYS);
535 
536  ffurl_close(h);
537  return ret;
538 }
539 
540 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options)
541 {
542  URLContext *h = NULL;
543  AVIODirContext *ctx = NULL;
544  int ret;
545  av_assert0(s);
546 
547  ctx = av_mallocz(sizeof(*ctx));
548  if (!ctx) {
549  ret = AVERROR(ENOMEM);
550  goto fail;
551  }
552 
553  if ((ret = ffurl_alloc(&h, url, AVIO_FLAG_READ, NULL)) < 0)
554  goto fail;
555 
556  if (h->prot->url_open_dir && h->prot->url_read_dir && h->prot->url_close_dir) {
557  if (options && h->prot->priv_data_class &&
558  (ret = av_opt_set_dict(h->priv_data, options)) < 0)
559  goto fail;
560  ret = h->prot->url_open_dir(h);
561  } else
562  ret = AVERROR(ENOSYS);
563  if (ret < 0)
564  goto fail;
565 
566  h->is_connected = 1;
567  ctx->url_context = h;
568  *s = ctx;
569  return 0;
570 
571  fail:
572  av_free(ctx);
573  *s = NULL;
574  ffurl_close(h);
575  return ret;
576 }
577 
578 int avio_read_dir(AVIODirContext *s, AVIODirEntry **next)
579 {
580  URLContext *h;
581  int ret;
582 
583  if (!s || !s->url_context)
584  return AVERROR(EINVAL);
585  h = s->url_context;
586  if ((ret = h->prot->url_read_dir(h, next)) < 0)
587  avio_free_directory_entry(next);
588  return ret;
589 }
590 
591 int avio_close_dir(AVIODirContext **s)
592 {
593  URLContext *h;
594 
595  av_assert0(s);
596  if (!(*s) || !(*s)->url_context)
597  return AVERROR(EINVAL);
598  h = (*s)->url_context;
599  h->prot->url_close_dir(h);
600  ffurl_close(h);
601  av_freep(s);
602  *s = NULL;
603  return 0;
604 }
605 
606 void avio_free_directory_entry(AVIODirEntry **entry)
607 {
608  if (!entry || !*entry)
609  return;
610  av_free((*entry)->name);
611  av_freep(entry);
612 }
613 
614 int64_t ffurl_size(URLContext *h)
615 {
616  int64_t pos, size;
617 
618  size = ffurl_seek(h, 0, AVSEEK_SIZE);
619  if (size < 0) {
620  pos = ffurl_seek(h, 0, SEEK_CUR);
621  if ((size = ffurl_seek(h, -1, SEEK_END)) < 0)
622  return size;
623  size++;
624  ffurl_seek(h, pos, SEEK_SET);
625  }
626  return size;
627 }
628 
629 int ffurl_get_file_handle(URLContext *h)
630 {
631  if (!h || !h->prot || !h->prot->url_get_file_handle)
632  return -1;
633  return h->prot->url_get_file_handle(h);
634 }
635 
636 int ffurl_get_multi_file_handle(URLContext *h, int **handles, int *numhandles)
637 {
638  if (!h || !h->prot)
639  return AVERROR(ENOSYS);
640  if (!h->prot->url_get_multi_file_handle) {
641  if (!h->prot->url_get_file_handle)
642  return AVERROR(ENOSYS);
643  *handles = av_malloc(sizeof(**handles));
644  if (!*handles)
645  return AVERROR(ENOMEM);
646  *numhandles = 1;
647  *handles[0] = h->prot->url_get_file_handle(h);
648  return 0;
649  }
650  return h->prot->url_get_multi_file_handle(h, handles, numhandles);
651 }
652 
653 int ffurl_get_short_seek(URLContext *h)
654 {
655  if (!h || !h->prot || !h->prot->url_get_short_seek)
656  return AVERROR(ENOSYS);
657  return h->prot->url_get_short_seek(h);
658 }
659 
660 int ffurl_shutdown(URLContext *h, int flags)
661 {
662  if (!h || !h->prot || !h->prot->url_shutdown)
663  return AVERROR(ENOSYS);
664  return h->prot->url_shutdown(h, flags);
665 }
666 
667 int ff_check_interrupt(AVIOInterruptCB *cb)
668 {
669  if (cb && cb->callback)
670  return cb->callback(cb->opaque);
671  return 0;
672 }
av_gettime_relative
int64_t av_gettime_relative(void)
Get the current time in microseconds since some unspecified starting point.
Definition: time.c:56
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
ffurl_context_class
const AVClass ffurl_context_class
Definition: avio.c:63
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
opt.h
URLContext::filename
char * filename
specified URL
Definition: url.h:42
av_opt_set_defaults
void av_opt_set_defaults(void *s)
Set the values of all AVOption fields to their default values.
Definition: opt.c:1305
URL_PROTOCOL_FLAG_NETWORK
#define URL_PROTOCOL_FLAG_NETWORK
Definition: url.h:34
URLProtocol::url_read
int(* url_read)(URLContext *h, unsigned char *buf, int size)
Read data from the protocol.
Definition: url.h:78
cb
static double cb(void *priv, double x, double y)
Definition: vf_geq.c:112
ffurl_seek
int64_t ffurl_seek(URLContext *h, int64_t pos, int whence)
Change the position that will be used by the next read/write operation on the resource accessed by h.
Definition: avio.c:437
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:55
AVIO_FLAG_READ_WRITE
#define AVIO_FLAG_READ_WRITE
read-write pseudo flag
Definition: avio.h:656
URLContext::max_packet_size
int max_packet_size
if non zero, the stream is packetized with this max packet size
Definition: url.h:44
AVOption
AVOption.
Definition: opt.h:246
AVSEEK_SIZE
#define AVSEEK_SIZE
ORing this as the "whence" parameter to a seek function causes it to return the filesize without seek...
Definition: avio.h:531
ffurl_close
int ffurl_close(URLContext *h)
Definition: avio.c:470
urlcontext_to_name
static const char * urlcontext_to_name(void *ptr)
Definition: avio.c:36
AVDictionary
Definition: dict.c:30
ff_network_close
void ff_network_close(void)
Definition: network.c:116
URLProtocol
Definition: url.h:54
os_support.h
ff_network_init
int ff_network_init(void)
Definition: network.c:58
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:31
AVIOInterruptCB
Callback for checking whether to abort blocking functions.
Definition: avio.h:58
URLContext::is_connected
int is_connected
Definition: url.h:46
fail
#define fail()
Definition: checkasm.h:120
start
void INT64 start
Definition: avisynth_c.h:767
ffurl_connect
int ffurl_connect(URLContext *uc, AVDictionary **options)
Connect an URLContext that has been allocated by ffurl_alloc.
Definition: avio.c:166
AVERROR_OPTION_NOT_FOUND
#define AVERROR_OPTION_NOT_FOUND
Option not found.
Definition: error.h:61
av_opt_set
int av_opt_set(void *obj, const char *name, const char *val, int search_flags)
Definition: opt.c:449
ff_check_interrupt
int ff_check_interrupt(AVIOInterruptCB *cb)
Check if the user has requested to interrupt a blocking function associated with cb.
Definition: avio.c:667
URLProtocol::url_open
int(* url_open)(URLContext *h, const char *url, int flags)
Definition: url.h:56
URLContext::priv_data
void * priv_data
Definition: url.h:41
avio_free_directory_entry
void avio_free_directory_entry(AVIODirEntry **entry)
Free entry allocated by avio_read_dir().
Definition: avio.c:606
URLProtocol::flags
int flags
Definition: url.h:92
avassert.h
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
buf
void * buf
Definition: avisynth_c.h:766
ffurl_open
int ffurl_open(URLContext **puc, const char *filename, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options)
Definition: avio.c:358
url_alloc_for_protocol
static int url_alloc_for_protocol(URLContext **puc, const URLProtocol *up, const char *filename, int flags, const AVIOInterruptCB *int_cb)
Definition: avio.c:73
av_dict_get
AVDictionaryEntry * av_dict_get(const AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
Get a dictionary entry with matching key.
Definition: dict.c:40
av_opt_set_dict
int av_opt_set_dict(void *obj, AVDictionary **options)
Set all the options from a given dictionary on an object.
Definition: opt.c:1603
ffurl_open_whitelist
int ffurl_open_whitelist(URLContext **puc, const char *filename, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options, const char *whitelist, const char *blacklist, URLContext *parent)
Create an URLContext for accessing to the resource indicated by url, and open it.
Definition: avio.c:307
retry_transfer_wrapper
static int retry_transfer_wrapper(URLContext *h, uint8_t *buf, int size, int size_min, int(*transfer_func)(URLContext *h, uint8_t *buf, int size))
Definition: avio.c:365
s
#define s(width, name)
Definition: cbs_vp9.c:257
AV_OPT_FLAG_ENCODING_PARAM
#define AV_OPT_FLAG_ENCODING_PARAM
a generic parameter which can be set by the user for muxing or encoding
Definition: opt.h:276
avpriv_io_move
int avpriv_io_move(const char *url_src, const char *url_dst)
Move or rename a resource.
Definition: avio.c:502
is_dos_path
static int is_dos_path(const char *path)
Definition: os_support.h:70
URLContext::flags
int flags
Definition: url.h:43
avio_close_dir
int avio_close_dir(AVIODirContext **s)
Close directory.
Definition: avio.c:591
AV_OPT_TYPE_INT64
@ AV_OPT_TYPE_INT64
Definition: opt.h:224
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
AVIO_FLAG_WRITE
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:655
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
ctx
AVFormatContext * ctx
Definition: movenc.c:48
key
const char * key
Definition: hwcontext_opencl.c:168
av_usleep
int av_usleep(unsigned usec)
Sleep for a period of time.
Definition: time.c:84
ffurl_accept
int ffurl_accept(URLContext *s, URLContext **c)
Accept an URLContext c on an URLContext s.
Definition: avio.c:226
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
ffurl_get_protocols
const URLProtocol ** ffurl_get_protocols(const char *whitelist, const char *blacklist)
Construct a list of protocols matching a given whitelist and/or blacklist.
Definition: protocols.c:109
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
URLContext::protocol_whitelist
const char * protocol_whitelist
Definition: url.h:49
D
#define D
Definition: avio.c:55
NULL
#define NULL
Definition: coverity.c:32
urlcontext_child_next
static void * urlcontext_child_next(void *obj, void *prev)
Definition: avio.c:45
av_match_list
int av_match_list(const char *name, const char *list, char separator)
Check if a name is in a list.
Definition: avstring.c:443
URLContext::protocol_blacklist
const char * protocol_blacklist
Definition: url.h:50
ffurl_shutdown
int ffurl_shutdown(URLContext *h, int flags)
Signal the URLContext that we are done reading or writing the stream.
Definition: avio.c:660
URL_SCHEME_CHARS
#define URL_SCHEME_CHARS
Definition: avio.c:246
av_opt_free
void av_opt_free(void *obj)
Free all allocated objects in obj.
Definition: opt.c:1558
time.h
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
avio_read_dir
int avio_read_dir(AVIODirContext *s, AVIODirEntry **next)
Get next directory entry.
Definition: avio.c:578
OFFSET
#define OFFSET(x)
Definition: avio.c:53
ffurl_get_multi_file_handle
int ffurl_get_multi_file_handle(URLContext *h, int **handles, int *numhandles)
Return the file descriptors associated with this URL.
Definition: avio.c:636
URLProtocol::priv_data_class
const AVClass * priv_data_class
Definition: url.h:91
FFMAX
#define FFMAX(a, b)
Definition: common.h:94
URL_PROTOCOL_FLAG_NESTED_SCHEME
#define URL_PROTOCOL_FLAG_NESTED_SCHEME
Definition: url.h:33
size
int size
Definition: twinvq_data.h:11134
AVIODirEntry
Describes single entry of the directory.
Definition: avio.h:86
URLProtocol::name
const char * name
Definition: url.h:55
URLProtocol::default_whitelist
const char * default_whitelist
Definition: url.h:99
avio_check
int avio_check(const char *url, int flags)
Return AVIO_FLAG_* access flags corresponding to the access permissions of the resource in url,...
Definition: avio.c:483
val
const char const char void * val
Definition: avisynth_c.h:863
avpriv_io_delete
int avpriv_io_delete(const char *url)
Delete a resource.
Definition: avio.c:524
FFMIN
#define FFMIN(a, b)
Definition: common.h:96
av_strstart
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
Definition: avstring.c:34
ffurl_get_short_seek
int ffurl_get_short_seek(URLContext *h)
Return the current short seek threshold value for this URL.
Definition: avio.c:653
ffurl_alloc
int ffurl_alloc(URLContext **puc, const char *filename, int flags, const AVIOInterruptCB *int_cb)
Create a URLContext for accessing to the resource indicated by url, but do not initiate the connectio...
Definition: avio.c:290
URLContext
Definition: url.h:38
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
URLContext::prot
const struct URLProtocol * prot
Definition: url.h:40
AV_OPT_FLAG_DECODING_PARAM
#define AV_OPT_FLAG_DECODING_PARAM
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:277
url.h
uint8_t
uint8_t
Definition: audio_convert.c:194
av_mallocz
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:236
avio_open_dir
int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options)
Open directory for reading.
Definition: avio.c:540
len
int len
Definition: vorbis_enc_data.h:452
int_cb
const AVIOInterruptCB int_cb
Definition: ffmpeg.c:481
ffurl_closep
int ffurl_closep(URLContext **hh)
Close the resource accessed by the URLContext h, and free the memory used by it.
Definition: avio.c:447
ret
ret
Definition: filter_design.txt:187
AVClass::class_name
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
AVIODirContext
Definition: avio.h:103
URLContext::interrupt_callback
AVIOInterruptCB interrupt_callback
Definition: url.h:47
avformat.h
dict.h
URLProtocol::url_move
int(* url_move)(URLContext *h_src, URLContext *h_dst)
Definition: url.h:98
network.h
options
static const AVOption options[]
Definition: avio.c:56
url_find_protocol
static const struct URLProtocol * url_find_protocol(const char *filename)
Definition: avio.c:251
ffurl_read
int ffurl_read(URLContext *h, unsigned char *buf, int size)
Read up to size bytes from the resource accessed by h, and store the read bytes in buf.
Definition: avio.c:410
ff_urlcontext_child_class_next
const AVClass * ff_urlcontext_child_class_next(const AVClass *prev)
Definition: protocols.c:74
URLContext::av_class
const AVClass * av_class
information for av_log().
Definition: url.h:39
ffurl_write
int ffurl_write(URLContext *h, const unsigned char *buf, int size)
Write size bytes from buf to the resource accessed by h.
Definition: avio.c:424
AVSEEK_FORCE
#define AVSEEK_FORCE
Passing this flag as the "whence" parameter to a seek function causes it to seek by any means (like r...
Definition: avio.h:539
URLContext::is_streamed
int is_streamed
true if streamed (no seek possible), default = false
Definition: url.h:45
AVIO_FLAG_READ
#define AVIO_FLAG_READ
read-only
Definition: avio.h:654
av_strdup
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:251
ffurl_read_complete
int ffurl_read_complete(URLContext *h, unsigned char *buf, int size)
Read as many bytes as possible (up to size), calling the read function multiple times if necessary.
Definition: avio.c:417
av_opt_copy
int av_opt_copy(void *dst, const void *src)
Copy options from src object into dest object.
Definition: opt.c:1716
URLProtocol::priv_data_size
int priv_data_size
Definition: url.h:90
av_free
#define av_free(p)
Definition: tableprint_vlc.h:34
AVDictionaryEntry
Definition: dict.h:81
ffurl_handshake
int ffurl_handshake(URLContext *c)
Perform one step of the protocol handshake to accept a new client.
Definition: avio.c:234
AVIO_FLAG_NONBLOCK
#define AVIO_FLAG_NONBLOCK
Use non-blocking mode.
Definition: avio.h:673
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
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
URLProtocol::url_write
int(* url_write)(URLContext *h, const unsigned char *buf, int size)
Definition: url.h:79
avio_find_protocol_name
const char * avio_find_protocol_name(const char *url)
Return the name of the protocol that will handle the passed URL.
Definition: avio.c:476
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:565
av_strlcpy
size_t av_strlcpy(char *dst, const char *src, size_t size)
Copy the string src to dst, but no more than size - 1 bytes, and null-terminate dst.
Definition: avstring.c:83
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
ffurl_size
int64_t ffurl_size(URLContext *h)
Return the filesize of the resource accessed by h, AVERROR(ENOSYS) if the operation is not supported ...
Definition: avio.c:614
h
h
Definition: vp9dsp_template.c:2038
AVERROR_EXIT
#define AVERROR_EXIT
Immediate exit was requested; the called function should not be restarted.
Definition: error.h:56
AVDictionaryEntry::value
char * value
Definition: dict.h:83
avstring.h
AV_OPT_TYPE_STRING
@ AV_OPT_TYPE_STRING
Definition: opt.h:227
AVERROR_PROTOCOL_NOT_FOUND
#define AVERROR_PROTOCOL_NOT_FOUND
Protocol not found.
Definition: error.h:63
ffurl_get_file_handle
int ffurl_get_file_handle(URLContext *h)
Return the file descriptor associated with this URL.
Definition: avio.c:629
URLProtocol::url_open2
int(* url_open2)(URLContext *h, const char *url, int flags, AVDictionary **options)
This callback is to be used by protocols which open further nested protocols.
Definition: url.h:62
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