FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
avio.h
Go to the documentation of this file.
1 /*
2  * copyright (c) 2001 Fabrice Bellard
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 #ifndef AVFORMAT_AVIO_H
21 #define AVFORMAT_AVIO_H
22 
23 /**
24  * @file
25  * @ingroup lavf_io
26  * Buffered I/O operations
27  */
28 
29 #include <stdint.h>
30 
31 #include "libavutil/common.h"
32 #include "libavutil/dict.h"
33 #include "libavutil/log.h"
34 
35 #include "libavformat/version.h"
36 
37 /**
38  * Seeking works like for a local file.
39  */
40 #define AVIO_SEEKABLE_NORMAL (1 << 0)
41 
42 /**
43  * Seeking by timestamp with avio_seek_time() is possible.
44  */
45 #define AVIO_SEEKABLE_TIME (1 << 1)
46 
47 /**
48  * Callback for checking whether to abort blocking functions.
49  * AVERROR_EXIT is returned in this case by the interrupted
50  * function. During blocking operations, callback is called with
51  * opaque as parameter. If the callback returns 1, the
52  * blocking operation will be aborted.
53  *
54  * No members can be added to this struct without a major bump, if
55  * new elements have been added after this struct in AVFormatContext
56  * or AVIOContext.
57  */
58 typedef struct AVIOInterruptCB {
59  int (*callback)(void*);
60  void *opaque;
62 
63 /**
64  * Directory entry types.
65  */
78 };
79 
80 /**
81  * Describes single entry of the directory.
82  *
83  * Only name and type fields are guaranteed be set.
84  * Rest of fields are protocol or/and platform dependent and might be unknown.
85  */
86 typedef struct AVIODirEntry {
87  char *name; /**< Filename */
88  int type; /**< Type of the entry */
89  int utf8; /**< Set to 1 when name is encoded with UTF-8, 0 otherwise.
90  Name can be encoded with UTF-8 even though 0 is set. */
91  int64_t size; /**< File size in bytes, -1 if unknown. */
92  int64_t modification_timestamp; /**< Time of last modification in microseconds since unix
93  epoch, -1 if unknown. */
94  int64_t access_timestamp; /**< Time of last access in microseconds since unix epoch,
95  -1 if unknown. */
96  int64_t status_change_timestamp; /**< Time of last status change in microseconds since unix
97  epoch, -1 if unknown. */
98  int64_t user_id; /**< User ID of owner, -1 if unknown. */
99  int64_t group_id; /**< Group ID of owner, -1 if unknown. */
100  int64_t filemode; /**< Unix file mode, -1 if unknown. */
101 } AVIODirEntry;
102 
103 typedef struct AVIODirContext {
106 
107 /**
108  * Different data types that can be returned via the AVIO
109  * write_data_type callback.
110  */
112  /**
113  * Header data; this needs to be present for the stream to be decodeable.
114  */
116  /**
117  * A point in the output bytestream where a decoder can start decoding
118  * (i.e. a keyframe). A demuxer/decoder given the data flagged with
119  * AVIO_DATA_MARKER_HEADER, followed by any AVIO_DATA_MARKER_SYNC_POINT,
120  * should give decodeable results.
121  */
123  /**
124  * A point in the output bytestream where a demuxer can start parsing
125  * (for non self synchronizing bytestream formats). That is, any
126  * non-keyframe packet start point.
127  */
129  /**
130  * This is any, unlabelled data. It can either be a muxer not marking
131  * any positions at all, it can be an actual boundary/sync point
132  * that the muxer chooses not to mark, or a later part of a packet/fragment
133  * that is cut into multiple write callbacks due to limited IO buffer size.
134  */
136  /**
137  * Trailer data, which doesn't contain actual content, but only for
138  * finalizing the output file.
139  */
141  /**
142  * A point in the output bytestream where the underlying AVIOContext might
143  * flush the buffer depending on latency or buffering requirements. Typically
144  * means the end of a packet.
145  */
147 };
148 
149 /**
150  * Bytestream IO Context.
151  * New fields can be added to the end with minor version bumps.
152  * Removal, reordering and changes to existing fields require a major
153  * version bump.
154  * sizeof(AVIOContext) must not be used outside libav*.
155  *
156  * @note None of the function pointers in AVIOContext should be called
157  * directly, they should only be set by the client application
158  * when implementing custom I/O. Normally these are set to the
159  * function pointers specified in avio_alloc_context()
160  */
161 typedef struct AVIOContext {
162  /**
163  * A class for private options.
164  *
165  * If this AVIOContext is created by avio_open2(), av_class is set and
166  * passes the options down to protocols.
167  *
168  * If this AVIOContext is manually allocated, then av_class may be set by
169  * the caller.
170  *
171  * warning -- this field can be NULL, be sure to not pass this AVIOContext
172  * to any av_opt_* functions in that case.
173  */
175 
176  /*
177  * The following shows the relationship between buffer, buf_ptr,
178  * buf_ptr_max, buf_end, buf_size, and pos, when reading and when writing
179  * (since AVIOContext is used for both):
180  *
181  **********************************************************************************
182  * READING
183  **********************************************************************************
184  *
185  * | buffer_size |
186  * |---------------------------------------|
187  * | |
188  *
189  * buffer buf_ptr buf_end
190  * +---------------+-----------------------+
191  * |/ / / / / / / /|/ / / / / / /| |
192  * read buffer: |/ / consumed / | to be read /| |
193  * |/ / / / / / / /|/ / / / / / /| |
194  * +---------------+-----------------------+
195  *
196  * pos
197  * +-------------------------------------------+-----------------+
198  * input file: | | |
199  * +-------------------------------------------+-----------------+
200  *
201  *
202  **********************************************************************************
203  * WRITING
204  **********************************************************************************
205  *
206  * | buffer_size |
207  * |--------------------------------------|
208  * | |
209  *
210  * buf_ptr_max
211  * buffer (buf_ptr) buf_end
212  * +-----------------------+--------------+
213  * |/ / / / / / / / / / / /| |
214  * write buffer: | / / to be flushed / / | |
215  * |/ / / / / / / / / / / /| |
216  * +-----------------------+--------------+
217  * buf_ptr can be in this
218  * due to a backward seek
219  *
220  * pos
221  * +-------------+----------------------------------------------+
222  * output file: | | |
223  * +-------------+----------------------------------------------+
224  *
225  */
226  unsigned char *buffer; /**< Start of the buffer. */
227  int buffer_size; /**< Maximum buffer size */
228  unsigned char *buf_ptr; /**< Current position in the buffer */
229  unsigned char *buf_end; /**< End of the data, may be less than
230  buffer+buffer_size if the read function returned
231  less data than requested, e.g. for streams where
232  no more data has been received yet. */
233  void *opaque; /**< A private pointer, passed to the read/write/seek/...
234  functions. */
235  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
236  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
237  int64_t (*seek)(void *opaque, int64_t offset, int whence);
238  int64_t pos; /**< position in the file of the current buffer */
239  int must_flush; /**< unused */
240  int eof_reached; /**< true if eof reached */
241  int write_flag; /**< true if open for writing */
243  unsigned long checksum;
244  unsigned char *checksum_ptr;
245  unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
246  int error; /**< contains the error code or 0 if no error happened */
247  /**
248  * Pause or resume playback for network streaming protocols - e.g. MMS.
249  */
250  int (*read_pause)(void *opaque, int pause);
251  /**
252  * Seek to a given timestamp in stream with the specified stream_index.
253  * Needed for some network streaming protocols which don't support seeking
254  * to byte position.
255  */
256  int64_t (*read_seek)(void *opaque, int stream_index,
257  int64_t timestamp, int flags);
258  /**
259  * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
260  */
261  int seekable;
262 
263  /**
264  * max filesize, used to limit allocations
265  * This field is internal to libavformat and access from outside is not allowed.
266  */
267  int64_t maxsize;
268 
269  /**
270  * avio_read and avio_write should if possible be satisfied directly
271  * instead of going through a buffer, and avio_seek will always
272  * call the underlying seek function directly.
273  */
274  int direct;
275 
276  /**
277  * Bytes read statistic
278  * This field is internal to libavformat and access from outside is not allowed.
279  */
280  int64_t bytes_read;
281 
282  /**
283  * seek statistic
284  * This field is internal to libavformat and access from outside is not allowed.
285  */
287 
288  /**
289  * writeout statistic
290  * This field is internal to libavformat and access from outside is not allowed.
291  */
293 
294  /**
295  * Original buffer size
296  * used internally after probing and ensure seekback to reset the buffer size
297  * This field is internal to libavformat and access from outside is not allowed.
298  */
300 
301  /**
302  * Threshold to favor readahead over seek.
303  * This is current internal only, do not use from outside.
304  */
306 
307  /**
308  * ',' separated list of allowed protocols.
309  */
310  const char *protocol_whitelist;
311 
312  /**
313  * ',' separated list of disallowed protocols.
314  */
315  const char *protocol_blacklist;
316 
317  /**
318  * A callback that is used instead of write_packet.
319  */
320  int (*write_data_type)(void *opaque, uint8_t *buf, int buf_size,
321  enum AVIODataMarkerType type, int64_t time);
322  /**
323  * If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT,
324  * but ignore them and treat them as AVIO_DATA_MARKER_UNKNOWN (to avoid needlessly
325  * small chunks of data returned from the callback).
326  */
328 
329  /**
330  * Internal, not meant to be used from outside of AVIOContext.
331  */
333  int64_t last_time;
334 
335  /**
336  * A callback that is used instead of short_seek_threshold.
337  * This is current internal only, do not use from outside.
338  */
340 
341  int64_t written;
342 
343  /**
344  * Maximum reached position before a backward seek in the write buffer,
345  * used keeping track of already written data for a later flush.
346  */
347  unsigned char *buf_ptr_max;
348 
349  /**
350  * Try to buffer at least this amount of data before flushing it
351  */
353 } AVIOContext;
354 
355 /**
356  * Return the name of the protocol that will handle the passed URL.
357  *
358  * NULL is returned if no protocol could be found for the given URL.
359  *
360  * @return Name of the protocol or NULL.
361  */
362 const char *avio_find_protocol_name(const char *url);
363 
364 /**
365  * Return AVIO_FLAG_* access flags corresponding to the access permissions
366  * of the resource in url, or a negative value corresponding to an
367  * AVERROR code in case of failure. The returned access flags are
368  * masked by the value in flags.
369  *
370  * @note This function is intrinsically unsafe, in the sense that the
371  * checked resource may change its existence or permission status from
372  * one call to another. Thus you should not trust the returned value,
373  * unless you are sure that no other processes are accessing the
374  * checked resource.
375  */
376 int avio_check(const char *url, int flags);
377 
378 /**
379  * Move or rename a resource.
380  *
381  * @note url_src and url_dst should share the same protocol and authority.
382  *
383  * @param url_src url to resource to be moved
384  * @param url_dst new url to resource if the operation succeeded
385  * @return >=0 on success or negative on error.
386  */
387 int avpriv_io_move(const char *url_src, const char *url_dst);
388 
389 /**
390  * Delete a resource.
391  *
392  * @param url resource to be deleted.
393  * @return >=0 on success or negative on error.
394  */
395 int avpriv_io_delete(const char *url);
396 
397 /**
398  * Open directory for reading.
399  *
400  * @param s directory read context. Pointer to a NULL pointer must be passed.
401  * @param url directory to be listed.
402  * @param options A dictionary filled with protocol-private options. On return
403  * this parameter will be destroyed and replaced with a dictionary
404  * containing options that were not found. May be NULL.
405  * @return >=0 on success or negative on error.
406  */
407 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
408 
409 /**
410  * Get next directory entry.
411  *
412  * Returned entry must be freed with avio_free_directory_entry(). In particular
413  * it may outlive AVIODirContext.
414  *
415  * @param s directory read context.
416  * @param[out] next next entry or NULL when no more entries.
417  * @return >=0 on success or negative on error. End of list is not considered an
418  * error.
419  */
421 
422 /**
423  * Close directory.
424  *
425  * @note Entries created using avio_read_dir() are not deleted and must be
426  * freeded with avio_free_directory_entry().
427  *
428  * @param s directory read context.
429  * @return >=0 on success or negative on error.
430  */
432 
433 /**
434  * Free entry allocated by avio_read_dir().
435  *
436  * @param entry entry to be freed.
437  */
439 
440 /**
441  * Allocate and initialize an AVIOContext for buffered I/O. It must be later
442  * freed with avio_context_free().
443  *
444  * @param buffer Memory block for input/output operations via AVIOContext.
445  * The buffer must be allocated with av_malloc() and friends.
446  * It may be freed and replaced with a new buffer by libavformat.
447  * AVIOContext.buffer holds the buffer currently in use,
448  * which must be later freed with av_free().
449  * @param buffer_size The buffer size is very important for performance.
450  * For protocols with fixed blocksize it should be set to this blocksize.
451  * For others a typical size is a cache page, e.g. 4kb.
452  * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
453  * @param opaque An opaque pointer to user-specific data.
454  * @param read_packet A function for refilling the buffer, may be NULL.
455  * @param write_packet A function for writing the buffer contents, may be NULL.
456  * The function may not change the input buffers content.
457  * @param seek A function for seeking to specified byte position, may be NULL.
458  *
459  * @return Allocated AVIOContext or NULL on failure.
460  */
462  unsigned char *buffer,
463  int buffer_size,
464  int write_flag,
465  void *opaque,
466  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
467  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
468  int64_t (*seek)(void *opaque, int64_t offset, int whence));
469 
470 /**
471  * Free the supplied IO context and everything associated with it.
472  *
473  * @param s Double pointer to the IO context. This function will write NULL
474  * into s.
475  */
477 
478 void avio_w8(AVIOContext *s, int b);
479 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
480 void avio_wl64(AVIOContext *s, uint64_t val);
481 void avio_wb64(AVIOContext *s, uint64_t val);
482 void avio_wl32(AVIOContext *s, unsigned int val);
483 void avio_wb32(AVIOContext *s, unsigned int val);
484 void avio_wl24(AVIOContext *s, unsigned int val);
485 void avio_wb24(AVIOContext *s, unsigned int val);
486 void avio_wl16(AVIOContext *s, unsigned int val);
487 void avio_wb16(AVIOContext *s, unsigned int val);
488 
489 /**
490  * Write a NULL-terminated string.
491  * @return number of bytes written.
492  */
493 int avio_put_str(AVIOContext *s, const char *str);
494 
495 /**
496  * Convert an UTF-8 string to UTF-16LE and write it.
497  * @param s the AVIOContext
498  * @param str NULL-terminated UTF-8 string
499  *
500  * @return number of bytes written.
501  */
502 int avio_put_str16le(AVIOContext *s, const char *str);
503 
504 /**
505  * Convert an UTF-8 string to UTF-16BE and write it.
506  * @param s the AVIOContext
507  * @param str NULL-terminated UTF-8 string
508  *
509  * @return number of bytes written.
510  */
511 int avio_put_str16be(AVIOContext *s, const char *str);
512 
513 /**
514  * Mark the written bytestream as a specific type.
515  *
516  * Zero-length ranges are omitted from the output.
517  *
518  * @param time the stream time the current bytestream pos corresponds to
519  * (in AV_TIME_BASE units), or AV_NOPTS_VALUE if unknown or not
520  * applicable
521  * @param type the kind of data written starting at the current pos
522  */
523 void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type);
524 
525 /**
526  * ORing this as the "whence" parameter to a seek function causes it to
527  * return the filesize without seeking anywhere. Supporting this is optional.
528  * If it is not supported then the seek function will return <0.
529  */
530 #define AVSEEK_SIZE 0x10000
531 
532 /**
533  * Passing this flag as the "whence" parameter to a seek function causes it to
534  * seek by any means (like reopening and linear reading) or other normally unreasonable
535  * means that can be extremely slow.
536  * This may be ignored by the seek code.
537  */
538 #define AVSEEK_FORCE 0x20000
539 
540 /**
541  * fseek() equivalent for AVIOContext.
542  * @return new position or AVERROR.
543  */
544 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
545 
546 /**
547  * Skip given number of bytes forward
548  * @return new position or AVERROR.
549  */
550 int64_t avio_skip(AVIOContext *s, int64_t offset);
551 
552 /**
553  * ftell() equivalent for AVIOContext.
554  * @return position or AVERROR.
555  */
557 {
558  return avio_seek(s, 0, SEEK_CUR);
559 }
560 
561 /**
562  * Get the filesize.
563  * @return filesize or AVERROR
564  */
565 int64_t avio_size(AVIOContext *s);
566 
567 /**
568  * feof() equivalent for AVIOContext.
569  * @return non zero if and only if end of file
570  */
571 int avio_feof(AVIOContext *s);
572 #if FF_API_URL_FEOF
573 /**
574  * @deprecated use avio_feof()
575  */
577 int url_feof(AVIOContext *s);
578 #endif
579 
580 /** @warning Writes up to 4 KiB per call */
581 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
582 
583 /**
584  * Force flushing of buffered data.
585  *
586  * For write streams, force the buffered data to be immediately written to the output,
587  * without to wait to fill the internal buffer.
588  *
589  * For read streams, discard all currently buffered data, and advance the
590  * reported file position to that of the underlying stream. This does not
591  * read new data, and does not perform any seeks.
592  */
593 void avio_flush(AVIOContext *s);
594 
595 /**
596  * Read size bytes from AVIOContext into buf.
597  * @return number of bytes read or AVERROR
598  */
599 int avio_read(AVIOContext *s, unsigned char *buf, int size);
600 
601 /**
602  * Read size bytes from AVIOContext into buf. Unlike avio_read(), this is allowed
603  * to read fewer bytes than requested. The missing bytes can be read in the next
604  * call. This always tries to read at least 1 byte.
605  * Useful to reduce latency in certain cases.
606  * @return number of bytes read or AVERROR
607  */
608 int avio_read_partial(AVIOContext *s, unsigned char *buf, int size);
609 
610 /**
611  * @name Functions for reading from AVIOContext
612  * @{
613  *
614  * @note return 0 if EOF, so you cannot use it if EOF handling is
615  * necessary
616  */
617 int avio_r8 (AVIOContext *s);
618 unsigned int avio_rl16(AVIOContext *s);
619 unsigned int avio_rl24(AVIOContext *s);
620 unsigned int avio_rl32(AVIOContext *s);
621 uint64_t avio_rl64(AVIOContext *s);
622 unsigned int avio_rb16(AVIOContext *s);
623 unsigned int avio_rb24(AVIOContext *s);
624 unsigned int avio_rb32(AVIOContext *s);
625 uint64_t avio_rb64(AVIOContext *s);
626 /**
627  * @}
628  */
629 
630 /**
631  * Read a string from pb into buf. The reading will terminate when either
632  * a NULL character was encountered, maxlen bytes have been read, or nothing
633  * more can be read from pb. The result is guaranteed to be NULL-terminated, it
634  * will be truncated if buf is too small.
635  * Note that the string is not interpreted or validated in any way, it
636  * might get truncated in the middle of a sequence for multi-byte encodings.
637  *
638  * @return number of bytes read (is always <= maxlen).
639  * If reading ends on EOF or error, the return value will be one more than
640  * bytes actually read.
641  */
642 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
643 
644 /**
645  * Read a UTF-16 string from pb and convert it to UTF-8.
646  * The reading will terminate when either a null or invalid character was
647  * encountered or maxlen bytes have been read.
648  * @return number of bytes read (is always <= maxlen)
649  */
650 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
651 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
652 
653 
654 /**
655  * @name URL open modes
656  * The flags argument to avio_open must be one of the following
657  * constants, optionally ORed with other flags.
658  * @{
659  */
660 #define AVIO_FLAG_READ 1 /**< read-only */
661 #define AVIO_FLAG_WRITE 2 /**< write-only */
662 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
663 /**
664  * @}
665  */
666 
667 /**
668  * Use non-blocking mode.
669  * If this flag is set, operations on the context will return
670  * AVERROR(EAGAIN) if they can not be performed immediately.
671  * If this flag is not set, operations on the context will never return
672  * AVERROR(EAGAIN).
673  * Note that this flag does not affect the opening/connecting of the
674  * context. Connecting a protocol will always block if necessary (e.g. on
675  * network protocols) but never hang (e.g. on busy devices).
676  * Warning: non-blocking protocols is work-in-progress; this flag may be
677  * silently ignored.
678  */
679 #define AVIO_FLAG_NONBLOCK 8
680 
681 /**
682  * Use direct mode.
683  * avio_read and avio_write should if possible be satisfied directly
684  * instead of going through a buffer, and avio_seek will always
685  * call the underlying seek function directly.
686  */
687 #define AVIO_FLAG_DIRECT 0x8000
688 
689 /**
690  * Create and initialize a AVIOContext for accessing the
691  * resource indicated by url.
692  * @note When the resource indicated by url has been opened in
693  * read+write mode, the AVIOContext can be used only for writing.
694  *
695  * @param s Used to return the pointer to the created AVIOContext.
696  * In case of failure the pointed to value is set to NULL.
697  * @param url resource to access
698  * @param flags flags which control how the resource indicated by url
699  * is to be opened
700  * @return >= 0 in case of success, a negative value corresponding to an
701  * AVERROR code in case of failure
702  */
703 int avio_open(AVIOContext **s, const char *url, int flags);
704 
705 /**
706  * Create and initialize a AVIOContext for accessing the
707  * resource indicated by url.
708  * @note When the resource indicated by url has been opened in
709  * read+write mode, the AVIOContext can be used only for writing.
710  *
711  * @param s Used to return the pointer to the created AVIOContext.
712  * In case of failure the pointed to value is set to NULL.
713  * @param url resource to access
714  * @param flags flags which control how the resource indicated by url
715  * is to be opened
716  * @param int_cb an interrupt callback to be used at the protocols level
717  * @param options A dictionary filled with protocol-private options. On return
718  * this parameter will be destroyed and replaced with a dict containing options
719  * that were not found. May be NULL.
720  * @return >= 0 in case of success, a negative value corresponding to an
721  * AVERROR code in case of failure
722  */
723 int avio_open2(AVIOContext **s, const char *url, int flags,
725 
726 /**
727  * Close the resource accessed by the AVIOContext s and free it.
728  * This function can only be used if s was opened by avio_open().
729  *
730  * The internal buffer is automatically flushed before closing the
731  * resource.
732  *
733  * @return 0 on success, an AVERROR < 0 on error.
734  * @see avio_closep
735  */
736 int avio_close(AVIOContext *s);
737 
738 /**
739  * Close the resource accessed by the AVIOContext *s, free it
740  * and set the pointer pointing to it to NULL.
741  * This function can only be used if s was opened by avio_open().
742  *
743  * The internal buffer is automatically flushed before closing the
744  * resource.
745  *
746  * @return 0 on success, an AVERROR < 0 on error.
747  * @see avio_close
748  */
749 int avio_closep(AVIOContext **s);
750 
751 
752 /**
753  * Open a write only memory stream.
754  *
755  * @param s new IO context
756  * @return zero if no error.
757  */
759 
760 /**
761  * Return the written size and a pointer to the buffer.
762  * The AVIOContext stream is left intact.
763  * The buffer must NOT be freed.
764  * No padding is added to the buffer.
765  *
766  * @param s IO context
767  * @param pbuffer pointer to a byte buffer
768  * @return the length of the byte buffer
769  */
770 int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
771 
772 /**
773  * Return the written size and a pointer to the buffer. The buffer
774  * must be freed with av_free().
775  * Padding of AV_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
776  *
777  * @param s IO context
778  * @param pbuffer pointer to a byte buffer
779  * @return the length of the byte buffer
780  */
781 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
782 
783 /**
784  * Iterate through names of available protocols.
785  *
786  * @param opaque A private pointer representing current protocol.
787  * It must be a pointer to NULL on first iteration and will
788  * be updated by successive calls to avio_enum_protocols.
789  * @param output If set to 1, iterate over output protocols,
790  * otherwise over input protocols.
791  *
792  * @return A static string containing the name of current protocol or NULL
793  */
794 const char *avio_enum_protocols(void **opaque, int output);
795 
796 /**
797  * Pause and resume playing - only meaningful if using a network streaming
798  * protocol (e.g. MMS).
799  *
800  * @param h IO context from which to call the read_pause function pointer
801  * @param pause 1 for pause, 0 for resume
802  */
803 int avio_pause(AVIOContext *h, int pause);
804 
805 /**
806  * Seek to a given timestamp relative to some component stream.
807  * Only meaningful if using a network streaming protocol (e.g. MMS.).
808  *
809  * @param h IO context from which to call the seek function pointers
810  * @param stream_index The stream index that the timestamp is relative to.
811  * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
812  * units from the beginning of the presentation.
813  * If a stream_index >= 0 is used and the protocol does not support
814  * seeking based on component streams, the call will fail.
815  * @param timestamp timestamp in AVStream.time_base units
816  * or if there is no stream specified then in AV_TIME_BASE units.
817  * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
818  * and AVSEEK_FLAG_ANY. The protocol may silently ignore
819  * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
820  * fail if used and not supported.
821  * @return >= 0 on success
822  * @see AVInputFormat::read_seek
823  */
824 int64_t avio_seek_time(AVIOContext *h, int stream_index,
825  int64_t timestamp, int flags);
826 
827 /* Avoid a warning. The header can not be included because it breaks c++. */
828 struct AVBPrint;
829 
830 /**
831  * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
832  *
833  * @return 0 for success (max_size bytes read or EOF reached), negative error
834  * code otherwise
835  */
836 int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
837 
838 /**
839  * Accept and allocate a client context on a server context.
840  * @param s the server context
841  * @param c the client context, must be unallocated
842  * @return >= 0 on success or a negative value corresponding
843  * to an AVERROR on failure
844  */
846 
847 /**
848  * Perform one step of the protocol handshake to accept a new client.
849  * This function must be called on a client returned by avio_accept() before
850  * using it as a read/write context.
851  * It is separate from avio_accept() because it may block.
852  * A step of the handshake is defined by places where the application may
853  * decide to change the proceedings.
854  * For example, on a protocol with a request header and a reply header, each
855  * one can constitute a step because the application may use the parameters
856  * from the request to change parameters in the reply; or each individual
857  * chunk of the request can constitute a step.
858  * If the handshake is already finished, avio_handshake() does nothing and
859  * returns 0 immediately.
860  *
861  * @param c the client context to perform the handshake on
862  * @return 0 on a complete and successful handshake
863  * > 0 if the handshake progressed, but is not complete
864  * < 0 for an AVERROR code
865  */
867 #endif /* AVFORMAT_AVIO_H */
int avio_open(AVIOContext **s, const char *url, int flags)
Create and initialize a AVIOContext for accessing the resource indicated by url.
Definition: aviobuf.c:1076
static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int unqueue)
Definition: ffmpeg.c:671
void avio_wb64(AVIOContext *s, uint64_t val)
Definition: aviobuf.c:468
const char const char void * val
Definition: avisynth_c.h:771
void avio_wl16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:474
const char * s
Definition: avisynth_c.h:768
Bytestream IO Context.
Definition: avio.h:161
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:334
int64_t(* read_seek)(void *opaque, int stream_index, int64_t timestamp, int flags)
Seek to a given timestamp in stream with the specified stream_index.
Definition: avio.h:256
int avpriv_io_delete(const char *url)
Delete a resource.
Definition: avio.c:519
int avio_put_str16be(AVIOContext *s, const char *str)
Convert an UTF-8 string to UTF-16BE and write it.
int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
Definition: aviobuf.c:1342
int64_t filemode
Unix file mode, -1 if unknown.
Definition: avio.h:100
int(* short_seek_get)(void *opaque)
A callback that is used instead of short_seek_threshold.
Definition: avio.h:339
const char * fmt
Definition: avisynth_c.h:769
int64_t last_time
Definition: avio.h:333
unsigned char * buf_ptr
Current position in the buffer.
Definition: avio.h:228
int writeout_count
writeout statistic This field is internal to libavformat and access from outside is not allowed...
Definition: avio.h:292
unsigned char * buf_end
End of the data, may be less than buffer+buffer_size if the read function returned less data than req...
Definition: avio.h:229
int write_flag
true if open for writing
Definition: avio.h:241
int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size)
Read contents of h into print buffer, up to max_size bytes, or up to EOF.
Definition: aviobuf.c:1183
Describes single entry of the directory.
Definition: avio.h:86
const char * b
Definition: vf_curves.c:113
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:244
int min_packet_size
Try to buffer at least this amount of data before flushing it.
Definition: avio.h:352
unsigned char * buffer
Start of the buffer.
Definition: avio.h:226
int avio_read_partial(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:706
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:329
int64_t(* seek)(void *opaque, int64_t offset, int whence)
Definition: avio.h:237
void * opaque
A private pointer, passed to the read/write/seek/...
Definition: avio.h:233
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:775
int64_t maxsize
max filesize, used to limit allocations This field is internal to libavformat and access from outside...
Definition: avio.h:267
int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen)
Read a UTF-16 string from pb and convert it to UTF-8.
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1313
void * opaque
Definition: avio.h:60
Trailer data, which doesn't contain actual content, but only for finalizing the output file...
Definition: avio.h:140
int64_t modification_timestamp
Time of last modification in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:92
Public dictionary API.
int avio_accept(AVIOContext *s, AVIOContext **c)
Accept and allocate a client context on a server context.
Definition: aviobuf.c:1201
void avio_wl32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:374
uint8_t
A point in the output bytestream where the underlying AVIOContext might flush the buffer depending on...
Definition: avio.h:146
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:790
void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type)
Mark the written bytestream as a specific type.
Definition: aviobuf.c:498
const AVClass * av_class
A class for private options.
Definition: avio.h:174
A point in the output bytestream where a demuxer can start parsing (for non self synchronizing bytest...
Definition: avio.h:128
int64_t bytes_read
Bytes read statistic This field is internal to libavformat and access from outside is not allowed...
Definition: avio.h:280
static int flags
Definition: log.c:57
ptrdiff_t size
Definition: opengl_enc.c:101
uint64_t avio_rb64(AVIOContext *s)
Definition: aviobuf.c:857
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:556
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:216
const OptionDef options[]
Definition: ffserver.c:3952
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:637
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:478
void avio_wl64(AVIOContext *s, uint64_t val)
Definition: aviobuf.c:462
int max_packet_size
Definition: avio.h:242
Callback for checking whether to abort blocking functions.
Definition: avio.h:58
AVIOContext * avio_alloc_context(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))
Allocate and initialize an AVIOContext for buffered I/O.
Definition: aviobuf.c:129
char * name
Filename.
Definition: avio.h:87
int64_t written
Definition: avio.h:341
int(* write_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:236
int(* callback)(void *)
Definition: avio.h:59
const AVIOInterruptCB int_cb
Definition: ffmpeg.c:464
int(* read_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:235
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:759
const char * avio_enum_protocols(void **opaque, int output)
Iterate through names of available protocols.
Definition: protocols.c:96
int avio_close(AVIOContext *s)
Close the resource accessed by the AVIOContext s and free it.
Definition: aviobuf.c:1112
int utf8
Set to 1 when name is encoded with UTF-8, 0 otherwise.
Definition: avio.h:89
const char * protocol_whitelist
',' separated list of allowed protocols.
Definition: avio.h:310
unsigned long checksum
Definition: avio.h:243
static const uint8_t offset[127][2]
Definition: vf_spp.c:92
int direct
avio_read and avio_write should if possible be satisfied directly instead of going through a buffer...
Definition: avio.h:274
const char * protocol_blacklist
',' separated list of disallowed protocols.
Definition: avio.h:315
#define av_printf_format(fmtpos, attrpos)
Definition: attributes.h:155
int seek_count
seek statistic This field is internal to libavformat and access from outside is not allowed...
Definition: avio.h:286
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:628
int(* write_data_type)(void *opaque, uint8_t *buf, int buf_size, enum AVIODataMarkerType type, int64_t time)
A callback that is used instead of write_packet.
Definition: avio.h:320
This is any, unlabelled data.
Definition: avio.h:135
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:261
int void avio_flush(AVIOContext *s)
Force flushing of buffered data.
Definition: aviobuf.c:236
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:783
void avio_free_directory_entry(AVIODirEntry **entry)
Free entry allocated by avio_read_dir().
Definition: avio.c:601
int64_t access_timestamp
Time of last access in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:94
unsigned char * checksum_ptr
Definition: avio.h:244
AVIODataMarkerType
Different data types that can be returned via the AVIO write_data_type callback.
Definition: avio.h:111
void avio_wb24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:492
int must_flush
unused
Definition: avio.h:239
Libavformat version macros.
unsigned long(* update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size)
Definition: avio.h:245
int64_t size
File size in bytes, -1 if unknown.
Definition: avio.h:91
int buffer_size
Maximum buffer size.
Definition: avio.h:227
int avpriv_io_move(const char *url_src, const char *url_dst)
Move or rename a resource.
Definition: avio.c:497
int avio_put_str(AVIOContext *s, const char *str)
Write a NULL-terminated string.
Definition: aviobuf.c:390
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
int type
Type of the entry.
Definition: avio.h:88
void avio_w8(AVIOContext *s, int b)
Definition: aviobuf.c:194
void * buf
Definition: avisynth_c.h:690
Definition: url.h:38
GLint GLenum type
Definition: opengl_enc.c:105
Describe the class of an AVClass context structure.
Definition: log.h:67
int64_t group_id
Group ID of owner, -1 if unknown.
Definition: avio.h:99
const char * avio_find_protocol_name(const char *url)
Return the name of the protocol that will handle the passed URL.
Definition: avio.c:471
int avio_put_str16le(AVIOContext *s, const char *str)
Convert an UTF-8 string to UTF-16LE and write it.
int avio_open2(AVIOContext **s, const char *url, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options)
Create and initialize a AVIOContext for accessing the resource indicated by url.
Definition: aviobuf.c:1100
int short_seek_threshold
Threshold to favor readahead over seek.
Definition: avio.h:305
int avio_handshake(AVIOContext *c)
Perform one step of the protocol handshake to accept a new client.
Definition: aviobuf.c:1213
int avio_close_dir(AVIODirContext **s)
Close directory.
Definition: avio.c:586
int ignore_boundary_point
If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT, but ignore them and treat them as AVIO_DATA_MARKER_UNKNOWN (to avoid needlessly small chunks of data returned from the callback).
Definition: avio.h:327
int error
contains the error code or 0 if no error happened
Definition: avio.h:246
void avio_wl24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:486
int avio_pause(AVIOContext *h, int pause)
Pause and resume playing - only meaningful if using a network streaming protocol (e.g.
Definition: aviobuf.c:1157
int(* read_pause)(void *opaque, int pause)
Pause or resume playback for network streaming protocols - e.g.
Definition: avio.h:250
void avio_wb16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:480
#define attribute_deprecated
Definition: attributes.h:94
int orig_buffer_size
Original buffer size used internally after probing and ensure seekback to reset the buffer size This ...
Definition: avio.h:299
enum AVIODataMarkerType current_type
Internal, not meant to be used from outside of AVIOContext.
Definition: avio.h:332
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:743
int
common internal and external API header
int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen)
int64_t status_change_timestamp
Time of last status change in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:96
AVIODirEntryType
Directory entry types.
Definition: avio.h:66
static double c[64]
void avio_context_free(AVIOContext **s)
Free the supplied IO context and everything associated with it.
Definition: aviobuf.c:146
int64_t pos
position in the file of the current buffer
Definition: avio.h:238
int64_t avio_seek_time(AVIOContext *h, int stream_index, int64_t timestamp, int flags)
Seek to a given timestamp relative to some component stream.
Definition: aviobuf.c:1164
unsigned char * buf_ptr_max
Maximum reached position before a backward seek in the write buffer, used keeping track of already wr...
Definition: avio.h:347
int avio_read_dir(AVIODirContext *s, AVIODirEntry **next)
Get next directory entry.
Definition: avio.c:573
A point in the output bytestream where a decoder can start decoding (i.e.
Definition: avio.h:122
int eof_reached
true if eof reached
Definition: avio.h:240
int64_t user_id
User ID of owner, -1 if unknown.
Definition: avio.h:98
int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options)
Open directory for reading.
Definition: avio.c:535
void avio_wb32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:382
#define av_always_inline
Definition: attributes.h:39
int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen)
Read a string from pb into buf.
Definition: aviobuf.c:815
int avio_feof(AVIOContext *s)
feof() equivalent for AVIOContext.
Definition: aviobuf.c:356
unsigned int avio_rl24(AVIOContext *s)
Definition: aviobuf.c:751
struct URLContext * url_context
Definition: avio.h:104
int avio_closep(AVIOContext **s)
Close the resource accessed by the AVIOContext *s, free it and set the pointer pointing to it to NULL...
Definition: aviobuf.c:1137
uint64_t avio_rl64(AVIOContext *s)
Definition: aviobuf.c:767
Header data; this needs to be present for the stream to be decodeable.
Definition: avio.h:115
GLuint buffer
Definition: opengl_enc.c:102
int avio_printf(AVIOContext *s, const char *fmt,...) av_printf_format(2
int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
Definition: aviobuf.c:1325