FFmpeg
avio.h
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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 public fields can be added with minor version bumps.
152  * Removal, reordering and changes to existing public fields require
153  * a major 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 eof_reached; /**< true if was unable to read due to error or eof */
240  int error; /**< contains the error code or 0 if no error happened */
241  int write_flag; /**< true if open for writing */
243  int min_packet_size; /**< Try to buffer at least this amount of data
244  before flushing it. */
245  unsigned long checksum;
246  unsigned char *checksum_ptr;
247  unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
248  /**
249  * Pause or resume playback for network streaming protocols - e.g. MMS.
250  */
251  int (*read_pause)(void *opaque, int pause);
252  /**
253  * Seek to a given timestamp in stream with the specified stream_index.
254  * Needed for some network streaming protocols which don't support seeking
255  * to byte position.
256  */
257  int64_t (*read_seek)(void *opaque, int stream_index,
258  int64_t timestamp, int flags);
259  /**
260  * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
261  */
262  int seekable;
263 
264  /**
265  * avio_read and avio_write should if possible be satisfied directly
266  * instead of going through a buffer, and avio_seek will always
267  * call the underlying seek function directly.
268  */
269  int direct;
270 
271  /**
272  * ',' separated list of allowed protocols.
273  */
274  const char *protocol_whitelist;
275 
276  /**
277  * ',' separated list of disallowed protocols.
278  */
279  const char *protocol_blacklist;
280 
281  /**
282  * A callback that is used instead of write_packet.
283  */
284  int (*write_data_type)(void *opaque, uint8_t *buf, int buf_size,
285  enum AVIODataMarkerType type, int64_t time);
286  /**
287  * If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT,
288  * but ignore them and treat them as AVIO_DATA_MARKER_UNKNOWN (to avoid needlessly
289  * small chunks of data returned from the callback).
290  */
292 
293  int64_t written;
294 
295  /**
296  * Maximum reached position before a backward seek in the write buffer,
297  * used keeping track of already written data for a later flush.
298  */
299  unsigned char *buf_ptr_max;
300 } AVIOContext;
301 
302 /**
303  * Return the name of the protocol that will handle the passed URL.
304  *
305  * NULL is returned if no protocol could be found for the given URL.
306  *
307  * @return Name of the protocol or NULL.
308  */
309 const char *avio_find_protocol_name(const char *url);
310 
311 /**
312  * Return AVIO_FLAG_* access flags corresponding to the access permissions
313  * of the resource in url, or a negative value corresponding to an
314  * AVERROR code in case of failure. The returned access flags are
315  * masked by the value in flags.
316  *
317  * @note This function is intrinsically unsafe, in the sense that the
318  * checked resource may change its existence or permission status from
319  * one call to another. Thus you should not trust the returned value,
320  * unless you are sure that no other processes are accessing the
321  * checked resource.
322  */
323 int avio_check(const char *url, int flags);
324 
325 /**
326  * Open directory for reading.
327  *
328  * @param s directory read context. Pointer to a NULL pointer must be passed.
329  * @param url directory to be listed.
330  * @param options A dictionary filled with protocol-private options. On return
331  * this parameter will be destroyed and replaced with a dictionary
332  * containing options that were not found. May be NULL.
333  * @return >=0 on success or negative on error.
334  */
335 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
336 
337 /**
338  * Get next directory entry.
339  *
340  * Returned entry must be freed with avio_free_directory_entry(). In particular
341  * it may outlive AVIODirContext.
342  *
343  * @param s directory read context.
344  * @param[out] next next entry or NULL when no more entries.
345  * @return >=0 on success or negative on error. End of list is not considered an
346  * error.
347  */
349 
350 /**
351  * Close directory.
352  *
353  * @note Entries created using avio_read_dir() are not deleted and must be
354  * freeded with avio_free_directory_entry().
355  *
356  * @param s directory read context.
357  * @return >=0 on success or negative on error.
358  */
360 
361 /**
362  * Free entry allocated by avio_read_dir().
363  *
364  * @param entry entry to be freed.
365  */
367 
368 /**
369  * Allocate and initialize an AVIOContext for buffered I/O. It must be later
370  * freed with avio_context_free().
371  *
372  * @param buffer Memory block for input/output operations via AVIOContext.
373  * The buffer must be allocated with av_malloc() and friends.
374  * It may be freed and replaced with a new buffer by libavformat.
375  * AVIOContext.buffer holds the buffer currently in use,
376  * which must be later freed with av_free().
377  * @param buffer_size The buffer size is very important for performance.
378  * For protocols with fixed blocksize it should be set to this blocksize.
379  * For others a typical size is a cache page, e.g. 4kb.
380  * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
381  * @param opaque An opaque pointer to user-specific data.
382  * @param read_packet A function for refilling the buffer, may be NULL.
383  * For stream protocols, must never return 0 but rather
384  * a proper AVERROR code.
385  * @param write_packet A function for writing the buffer contents, may be NULL.
386  * The function may not change the input buffers content.
387  * @param seek A function for seeking to specified byte position, may be NULL.
388  *
389  * @return Allocated AVIOContext or NULL on failure.
390  */
392  unsigned char *buffer,
393  int buffer_size,
394  int write_flag,
395  void *opaque,
396  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
397  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
398  int64_t (*seek)(void *opaque, int64_t offset, int whence));
399 
400 /**
401  * Free the supplied IO context and everything associated with it.
402  *
403  * @param s Double pointer to the IO context. This function will write NULL
404  * into s.
405  */
407 
408 void avio_w8(AVIOContext *s, int b);
409 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
410 void avio_wl64(AVIOContext *s, uint64_t val);
411 void avio_wb64(AVIOContext *s, uint64_t val);
412 void avio_wl32(AVIOContext *s, unsigned int val);
413 void avio_wb32(AVIOContext *s, unsigned int val);
414 void avio_wl24(AVIOContext *s, unsigned int val);
415 void avio_wb24(AVIOContext *s, unsigned int val);
416 void avio_wl16(AVIOContext *s, unsigned int val);
417 void avio_wb16(AVIOContext *s, unsigned int val);
418 
419 /**
420  * Write a NULL-terminated string.
421  * @return number of bytes written.
422  */
423 int avio_put_str(AVIOContext *s, const char *str);
424 
425 /**
426  * Convert an UTF-8 string to UTF-16LE and write it.
427  * @param s the AVIOContext
428  * @param str NULL-terminated UTF-8 string
429  *
430  * @return number of bytes written.
431  */
432 int avio_put_str16le(AVIOContext *s, const char *str);
433 
434 /**
435  * Convert an UTF-8 string to UTF-16BE and write it.
436  * @param s the AVIOContext
437  * @param str NULL-terminated UTF-8 string
438  *
439  * @return number of bytes written.
440  */
441 int avio_put_str16be(AVIOContext *s, const char *str);
442 
443 /**
444  * Mark the written bytestream as a specific type.
445  *
446  * Zero-length ranges are omitted from the output.
447  *
448  * @param time the stream time the current bytestream pos corresponds to
449  * (in AV_TIME_BASE units), or AV_NOPTS_VALUE if unknown or not
450  * applicable
451  * @param type the kind of data written starting at the current pos
452  */
453 void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type);
454 
455 /**
456  * ORing this as the "whence" parameter to a seek function causes it to
457  * return the filesize without seeking anywhere. Supporting this is optional.
458  * If it is not supported then the seek function will return <0.
459  */
460 #define AVSEEK_SIZE 0x10000
461 
462 /**
463  * Passing this flag as the "whence" parameter to a seek function causes it to
464  * seek by any means (like reopening and linear reading) or other normally unreasonable
465  * means that can be extremely slow.
466  * This may be ignored by the seek code.
467  */
468 #define AVSEEK_FORCE 0x20000
469 
470 /**
471  * fseek() equivalent for AVIOContext.
472  * @return new position or AVERROR.
473  */
474 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
475 
476 /**
477  * Skip given number of bytes forward
478  * @return new position or AVERROR.
479  */
480 int64_t avio_skip(AVIOContext *s, int64_t offset);
481 
482 /**
483  * ftell() equivalent for AVIOContext.
484  * @return position or AVERROR.
485  */
487 {
488  return avio_seek(s, 0, SEEK_CUR);
489 }
490 
491 /**
492  * Get the filesize.
493  * @return filesize or AVERROR
494  */
495 int64_t avio_size(AVIOContext *s);
496 
497 /**
498  * Similar to feof() but also returns nonzero on read errors.
499  * @return non zero if and only if at end of file or a read error happened when reading.
500  */
501 int avio_feof(AVIOContext *s);
502 
503 /**
504  * Writes a formatted string to the context.
505  * @return number of bytes written, < 0 on error.
506  */
507 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
508 
509 /**
510  * Write a NULL terminated array of strings to the context.
511  * Usually you don't need to use this function directly but its macro wrapper,
512  * avio_print.
513  */
514 void avio_print_string_array(AVIOContext *s, const char *strings[]);
515 
516 /**
517  * Write strings (const char *) to the context.
518  * This is a convenience macro around avio_print_string_array and it
519  * automatically creates the string array from the variable argument list.
520  * For simple string concatenations this function is more performant than using
521  * avio_printf since it does not need a temporary buffer.
522  */
523 #define avio_print(s, ...) \
524  avio_print_string_array(s, (const char*[]){__VA_ARGS__, NULL})
525 
526 /**
527  * Force flushing of buffered data.
528  *
529  * For write streams, force the buffered data to be immediately written to the output,
530  * without to wait to fill the internal buffer.
531  *
532  * For read streams, discard all currently buffered data, and advance the
533  * reported file position to that of the underlying stream. This does not
534  * read new data, and does not perform any seeks.
535  */
536 void avio_flush(AVIOContext *s);
537 
538 /**
539  * Read size bytes from AVIOContext into buf.
540  * @return number of bytes read or AVERROR
541  */
542 int avio_read(AVIOContext *s, unsigned char *buf, int size);
543 
544 /**
545  * Read size bytes from AVIOContext into buf. Unlike avio_read(), this is allowed
546  * to read fewer bytes than requested. The missing bytes can be read in the next
547  * call. This always tries to read at least 1 byte.
548  * Useful to reduce latency in certain cases.
549  * @return number of bytes read or AVERROR
550  */
551 int avio_read_partial(AVIOContext *s, unsigned char *buf, int size);
552 
553 /**
554  * @name Functions for reading from AVIOContext
555  * @{
556  *
557  * @note return 0 if EOF, so you cannot use it if EOF handling is
558  * necessary
559  */
560 int avio_r8 (AVIOContext *s);
561 unsigned int avio_rl16(AVIOContext *s);
562 unsigned int avio_rl24(AVIOContext *s);
563 unsigned int avio_rl32(AVIOContext *s);
564 uint64_t avio_rl64(AVIOContext *s);
565 unsigned int avio_rb16(AVIOContext *s);
566 unsigned int avio_rb24(AVIOContext *s);
567 unsigned int avio_rb32(AVIOContext *s);
568 uint64_t avio_rb64(AVIOContext *s);
569 /**
570  * @}
571  */
572 
573 /**
574  * Read a string from pb into buf. The reading will terminate when either
575  * a NULL character was encountered, maxlen bytes have been read, or nothing
576  * more can be read from pb. The result is guaranteed to be NULL-terminated, it
577  * will be truncated if buf is too small.
578  * Note that the string is not interpreted or validated in any way, it
579  * might get truncated in the middle of a sequence for multi-byte encodings.
580  *
581  * @return number of bytes read (is always <= maxlen).
582  * If reading ends on EOF or error, the return value will be one more than
583  * bytes actually read.
584  */
585 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
586 
587 /**
588  * Read a UTF-16 string from pb and convert it to UTF-8.
589  * The reading will terminate when either a null or invalid character was
590  * encountered or maxlen bytes have been read.
591  * @return number of bytes read (is always <= maxlen)
592  */
593 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
594 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
595 
596 
597 /**
598  * @name URL open modes
599  * The flags argument to avio_open must be one of the following
600  * constants, optionally ORed with other flags.
601  * @{
602  */
603 #define AVIO_FLAG_READ 1 /**< read-only */
604 #define AVIO_FLAG_WRITE 2 /**< write-only */
605 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
606 /**
607  * @}
608  */
609 
610 /**
611  * Use non-blocking mode.
612  * If this flag is set, operations on the context will return
613  * AVERROR(EAGAIN) if they can not be performed immediately.
614  * If this flag is not set, operations on the context will never return
615  * AVERROR(EAGAIN).
616  * Note that this flag does not affect the opening/connecting of the
617  * context. Connecting a protocol will always block if necessary (e.g. on
618  * network protocols) but never hang (e.g. on busy devices).
619  * Warning: non-blocking protocols is work-in-progress; this flag may be
620  * silently ignored.
621  */
622 #define AVIO_FLAG_NONBLOCK 8
623 
624 /**
625  * Use direct mode.
626  * avio_read and avio_write should if possible be satisfied directly
627  * instead of going through a buffer, and avio_seek will always
628  * call the underlying seek function directly.
629  */
630 #define AVIO_FLAG_DIRECT 0x8000
631 
632 /**
633  * Create and initialize a AVIOContext for accessing the
634  * resource indicated by url.
635  * @note When the resource indicated by url has been opened in
636  * read+write mode, the AVIOContext can be used only for writing.
637  *
638  * @param s Used to return the pointer to the created AVIOContext.
639  * In case of failure the pointed to value is set to NULL.
640  * @param url resource to access
641  * @param flags flags which control how the resource indicated by url
642  * is to be opened
643  * @return >= 0 in case of success, a negative value corresponding to an
644  * AVERROR code in case of failure
645  */
646 int avio_open(AVIOContext **s, const char *url, int flags);
647 
648 /**
649  * Create and initialize a AVIOContext for accessing the
650  * resource indicated by url.
651  * @note When the resource indicated by url has been opened in
652  * read+write mode, the AVIOContext can be used only for writing.
653  *
654  * @param s Used to return the pointer to the created AVIOContext.
655  * In case of failure the pointed to value is set to NULL.
656  * @param url resource to access
657  * @param flags flags which control how the resource indicated by url
658  * is to be opened
659  * @param int_cb an interrupt callback to be used at the protocols level
660  * @param options A dictionary filled with protocol-private options. On return
661  * this parameter will be destroyed and replaced with a dict containing options
662  * that were not found. May be NULL.
663  * @return >= 0 in case of success, a negative value corresponding to an
664  * AVERROR code in case of failure
665  */
666 int avio_open2(AVIOContext **s, const char *url, int flags,
668 
669 /**
670  * Close the resource accessed by the AVIOContext s and free it.
671  * This function can only be used if s was opened by avio_open().
672  *
673  * The internal buffer is automatically flushed before closing the
674  * resource.
675  *
676  * @return 0 on success, an AVERROR < 0 on error.
677  * @see avio_closep
678  */
679 int avio_close(AVIOContext *s);
680 
681 /**
682  * Close the resource accessed by the AVIOContext *s, free it
683  * and set the pointer pointing to it to NULL.
684  * This function can only be used if s was opened by avio_open().
685  *
686  * The internal buffer is automatically flushed before closing the
687  * resource.
688  *
689  * @return 0 on success, an AVERROR < 0 on error.
690  * @see avio_close
691  */
692 int avio_closep(AVIOContext **s);
693 
694 
695 /**
696  * Open a write only memory stream.
697  *
698  * @param s new IO context
699  * @return zero if no error.
700  */
702 
703 /**
704  * Return the written size and a pointer to the buffer.
705  * The AVIOContext stream is left intact.
706  * The buffer must NOT be freed.
707  * No padding is added to the buffer.
708  *
709  * @param s IO context
710  * @param pbuffer pointer to a byte buffer
711  * @return the length of the byte buffer
712  */
713 int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
714 
715 /**
716  * Return the written size and a pointer to the buffer. The buffer
717  * must be freed with av_free().
718  * Padding of AV_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
719  *
720  * @param s IO context
721  * @param pbuffer pointer to a byte buffer
722  * @return the length of the byte buffer
723  */
724 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
725 
726 /**
727  * Iterate through names of available protocols.
728  *
729  * @param opaque A private pointer representing current protocol.
730  * It must be a pointer to NULL on first iteration and will
731  * be updated by successive calls to avio_enum_protocols.
732  * @param output If set to 1, iterate over output protocols,
733  * otherwise over input protocols.
734  *
735  * @return A static string containing the name of current protocol or NULL
736  */
737 const char *avio_enum_protocols(void **opaque, int output);
738 
739 /**
740  * Get AVClass by names of available protocols.
741  *
742  * @return A AVClass of input protocol name or NULL
743  */
744 const AVClass *avio_protocol_get_class(const char *name);
745 
746 /**
747  * Pause and resume playing - only meaningful if using a network streaming
748  * protocol (e.g. MMS).
749  *
750  * @param h IO context from which to call the read_pause function pointer
751  * @param pause 1 for pause, 0 for resume
752  */
753 int avio_pause(AVIOContext *h, int pause);
754 
755 /**
756  * Seek to a given timestamp relative to some component stream.
757  * Only meaningful if using a network streaming protocol (e.g. MMS.).
758  *
759  * @param h IO context from which to call the seek function pointers
760  * @param stream_index The stream index that the timestamp is relative to.
761  * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
762  * units from the beginning of the presentation.
763  * If a stream_index >= 0 is used and the protocol does not support
764  * seeking based on component streams, the call will fail.
765  * @param timestamp timestamp in AVStream.time_base units
766  * or if there is no stream specified then in AV_TIME_BASE units.
767  * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
768  * and AVSEEK_FLAG_ANY. The protocol may silently ignore
769  * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
770  * fail if used and not supported.
771  * @return >= 0 on success
772  * @see AVInputFormat::read_seek
773  */
774 int64_t avio_seek_time(AVIOContext *h, int stream_index,
775  int64_t timestamp, int flags);
776 
777 /* Avoid a warning. The header can not be included because it breaks c++. */
778 struct AVBPrint;
779 
780 /**
781  * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
782  *
783  * @return 0 for success (max_size bytes read or EOF reached), negative error
784  * code otherwise
785  */
786 int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
787 
788 /**
789  * Accept and allocate a client context on a server context.
790  * @param s the server context
791  * @param c the client context, must be unallocated
792  * @return >= 0 on success or a negative value corresponding
793  * to an AVERROR on failure
794  */
796 
797 /**
798  * Perform one step of the protocol handshake to accept a new client.
799  * This function must be called on a client returned by avio_accept() before
800  * using it as a read/write context.
801  * It is separate from avio_accept() because it may block.
802  * A step of the handshake is defined by places where the application may
803  * decide to change the proceedings.
804  * For example, on a protocol with a request header and a reply header, each
805  * one can constitute a step because the application may use the parameters
806  * from the request to change parameters in the reply; or each individual
807  * chunk of the request can constitute a step.
808  * If the handshake is already finished, avio_handshake() does nothing and
809  * returns 0 immediately.
810  *
811  * @param c the client context to perform the handshake on
812  * @return 0 on a complete and successful handshake
813  * > 0 if the handshake progressed, but is not complete
814  * < 0 for an AVERROR code
815  */
817 #endif /* AVFORMAT_AVIO_H */
name
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default minimum maximum flags name is the option name
Definition: writing_filters.txt:88
AVIO_DATA_MARKER_BOUNDARY_POINT
@ AVIO_DATA_MARKER_BOUNDARY_POINT
A point in the output bytestream where a demuxer can start parsing (for non self synchronizing bytest...
Definition: avio.h:128
avio_protocol_get_class
const AVClass * avio_protocol_get_class(const char *name)
Get AVClass by names of available protocols.
Definition: protocols.c:109
AVIOContext::seek
int64_t(* seek)(void *opaque, int64_t offset, int whence)
Definition: avio.h:237
avio_close
int avio_close(AVIOContext *s)
Close the resource accessed by the AVIOContext s and free it.
Definition: aviobuf.c:1213
avio_context_free
void avio_context_free(AVIOContext **s)
Free the supplied IO context and everything associated with it.
Definition: aviobuf.c:147
output
filter_frame For filters that do not use the this method is called when a frame is pushed to the filter s input It can be called at any time except in a reentrant way If the input frame is enough to produce output
Definition: filter_design.txt:225
avio_get_str16be
int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen)
AVIODirEntry::utf8
int utf8
Set to 1 when name is encoded with UTF-8, 0 otherwise.
Definition: avio.h:89
AVIOContext::protocol_blacklist
const char * protocol_blacklist
',' separated list of disallowed protocols.
Definition: avio.h:279
AVIODirEntry::type
int type
Type of the entry.
Definition: avio.h:88
avio_read_dir
int avio_read_dir(AVIODirContext *s, AVIODirEntry **next)
Get next directory entry.
Definition: avio.c:569
b
#define b
Definition: input.c:40
AVIO_ENTRY_NAMED_PIPE
@ AVIO_ENTRY_NAMED_PIPE
Definition: avio.h:71
avio_enum_protocols
const char * avio_enum_protocols(void **opaque, int output)
Iterate through names of available protocols.
Definition: protocols.c:94
AVIOContext::error
int error
contains the error code or 0 if no error happened
Definition: avio.h:240
avio_wl64
void avio_wl64(AVIOContext *s, uint64_t val)
Definition: aviobuf.c:439
AVIOContext::max_packet_size
int max_packet_size
Definition: avio.h:242
AVDictionary
Definition: dict.c:30
AVIODataMarkerType
AVIODataMarkerType
Different data types that can be returned via the AVIO write_data_type callback.
Definition: avio.h:111
avio_size
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:338
avio_get_dyn_buf
int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
Definition: aviobuf.c:1437
AVIO_ENTRY_UNKNOWN
@ AVIO_ENTRY_UNKNOWN
Definition: avio.h:67
AVIOInterruptCB
Callback for checking whether to abort blocking functions.
Definition: avio.h:58
AVIODirEntry::access_timestamp
int64_t access_timestamp
Time of last access in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:94
avio_wl16
void avio_wl16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:451
avio_handshake
int avio_handshake(AVIOContext *c)
Perform one step of the protocol handshake to accept a new client.
Definition: aviobuf.c:1326
avio_write_marker
void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type)
Mark the written bytestream as a specific type.
Definition: aviobuf.c:475
avio_open2
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:1207
avio_close_dir
int avio_close_dir(AVIODirContext **s)
Close directory.
Definition: avio.c:582
AVIO_ENTRY_DIRECTORY
@ AVIO_ENTRY_DIRECTORY
Definition: avio.h:70
avio_seek_time
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:1278
AVIO_ENTRY_CHARACTER_DEVICE
@ AVIO_ENTRY_CHARACTER_DEVICE
Definition: avio.h:69
AVIOContext::pos
int64_t pos
position in the file of the current buffer
Definition: avio.h:238
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:486
val
static double val(void *priv, double ch)
Definition: aeval.c:76
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition: writing_filters.txt:86
avio_rl16
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:726
AVIODirEntry::modification_timestamp
int64_t modification_timestamp
Time of last modification in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:92
avio_close_dyn_buf
int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
Definition: aviobuf.c:1470
avio_rb32
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:773
AVIO_ENTRY_SYMBOLIC_LINK
@ AVIO_ENTRY_SYMBOLIC_LINK
Definition: avio.h:72
avio_get_str16le
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.
avio_open_dyn_buf
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1425
s
#define s(width, name)
Definition: cbs_vp9.c:257
avio_free_directory_entry
void avio_free_directory_entry(AVIODirEntry **entry)
Free entry allocated by avio_read_dir().
Definition: avio.c:597
avio_read_to_bprint
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:1297
avio_print_string_array
int void avio_print_string_array(AVIOContext *s, const char *strings[])
Write a NULL terminated array of strings to the context.
Definition: aviobuf.c:1265
AVIOContext::write_flag
int write_flag
true if open for writing
Definition: avio.h:241
avio_flush
void avio_flush(AVIOContext *s)
Force flushing of buffered data.
Definition: aviobuf.c:238
AVIODirEntryType
AVIODirEntryType
Directory entry types.
Definition: avio.h:66
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
AVIOContext::min_packet_size
int min_packet_size
Try to buffer at least this amount of data before flushing it.
Definition: avio.h:243
AVIODirEntry::size
int64_t size
File size in bytes, -1 if unknown.
Definition: avio.h:91
AVIO_DATA_MARKER_TRAILER
@ AVIO_DATA_MARKER_TRAILER
Trailer data, which doesn't contain actual content, but only for finalizing the output file.
Definition: avio.h:140
AVIOContext::read_pause
int(* read_pause)(void *opaque, int pause)
Pause or resume playback for network streaming protocols - e.g.
Definition: avio.h:251
AVIODirEntry::name
char * name
Filename.
Definition: avio.h:87
avio_rb64
uint64_t avio_rb64(AVIOContext *s)
Definition: aviobuf.c:920
av_printf_format
#define av_printf_format(fmtpos, attrpos)
Definition: attributes.h:161
avio_accept
int avio_accept(AVIOContext *s, AVIOContext **c)
Accept and allocate a client context on a server context.
Definition: aviobuf.c:1315
AVIO_ENTRY_FILE
@ AVIO_ENTRY_FILE
Definition: avio.h:74
avio_pause
int avio_pause(AVIOContext *h, int pause)
Pause and resume playing - only meaningful if using a network streaming protocol (e....
Definition: aviobuf.c:1271
avio_w8
void avio_w8(AVIOContext *s, int b)
Definition: aviobuf.c:196
AVIODirEntry::group_id
int64_t group_id
Group ID of owner, -1 if unknown.
Definition: avio.h:99
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
AVIODirEntry::filemode
int64_t filemode
Unix file mode, -1 if unknown.
Definition: avio.h:100
AVIOContext::protocol_whitelist
const char * protocol_whitelist
',' separated list of allowed protocols.
Definition: avio.h:274
options
const OptionDef options[]
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:742
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
avio_rb24
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:766
AVIOContext::seekable
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:262
AVIOContext::buf_end
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
avio_get_str
int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen)
Read a string from pb into buf.
Definition: aviobuf.c:878
AVIOContext::write_data_type
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:284
size
int size
Definition: twinvq_data.h:10344
AVIODirEntry
Describes single entry of the directory.
Definition: avio.h:86
AVIO_DATA_MARKER_SYNC_POINT
@ AVIO_DATA_MARKER_SYNC_POINT
A point in the output bytestream where a decoder can start decoding (i.e.
Definition: avio.h:122
avio_write
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:218
avio_wb32
void avio_wb32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:379
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:616
AVIOContext::write_packet
int(* write_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:236
avio_wl32
void avio_wl32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:371
AVIOContext::checksum_ptr
unsigned char * checksum_ptr
Definition: avio.h:246
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
AVIODirEntry::status_change_timestamp
int64_t status_change_timestamp
Time of last status change in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:96
AVIO_ENTRY_SOCKET
@ AVIO_ENTRY_SOCKET
Definition: avio.h:73
write_packet
static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int unqueue)
Definition: ffmpeg.c:731
AVIODirEntry::user_id
int64_t user_id
User ID of owner, -1 if unknown.
Definition: avio.h:98
avio_closep
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:1239
AVIOContext::opaque
void * opaque
A private pointer, passed to the read/write/seek/...
Definition: avio.h:233
AVIOContext::direct
int direct
avio_read and avio_write should if possible be satisfied directly instead of going through a buffer,...
Definition: avio.h:269
URLContext
Definition: url.h:38
log.h
avio_rl24
unsigned int avio_rl24(AVIOContext *s)
Definition: aviobuf.c:734
common.h
av_always_inline
#define av_always_inline
Definition: attributes.h:49
avio_alloc_context
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:130
int_cb
const AVIOInterruptCB int_cb
Definition: ffmpeg.c:513
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:474
AVIOInterruptCB::opaque
void * opaque
Definition: avio.h:60
AVIO_DATA_MARKER_UNKNOWN
@ AVIO_DATA_MARKER_UNKNOWN
This is any, unlabelled data.
Definition: avio.h:135
version.h
AVIO_ENTRY_BLOCK_DEVICE
@ AVIO_ENTRY_BLOCK_DEVICE
Definition: avio.h:68
AVIOContext::checksum
unsigned long checksum
Definition: avio.h:245
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
AVIODirContext
Definition: avio.h:103
avio_rb16
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:758
AVIOContext::ignore_boundary_point
int ignore_boundary_point
If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT,...
Definition: avio.h:291
dict.h
AVIOContext::written
int64_t written
Definition: avio.h:293
avio_printf
int avio_printf(AVIOContext *s, const char *fmt,...) av_printf_format(2
Writes a formatted string to the context.
avio_put_str16be
int avio_put_str16be(AVIOContext *s, const char *str)
Convert an UTF-8 string to UTF-16BE and write it.
AVIOContext::buf_ptr_max
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:299
buffer
the frame and frame reference mechanism is intended to as much as expensive copies of that data while still allowing the filters to produce correct results The data is stored in buffers represented by AVFrame structures Several references can point to the same frame buffer
Definition: filter_design.txt:49
AVIOContext::update_checksum
unsigned long(* update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size)
Definition: avio.h:247
AVIO_DATA_MARKER_HEADER
@ AVIO_DATA_MARKER_HEADER
Header data; this needs to be present for the stream to be decodeable.
Definition: avio.h:115
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:625
AVIOContext::eof_reached
int eof_reached
true if was unable to read due to error or eof
Definition: avio.h:239
avio_open
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:1181
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:333
AVIO_ENTRY_WORKGROUP
@ AVIO_ENTRY_WORKGROUP
Definition: avio.h:77
avio_wb64
void avio_wb64(AVIOContext *s, uint64_t val)
Definition: aviobuf.c:445
AVIOContext::read_packet
int(* read_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:235
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:467
AVIOInterruptCB::callback
int(* callback)(void *)
Definition: avio.h:59
avio_wb24
void avio_wb24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:469
AVIOContext::buffer
unsigned char * buffer
Start of the buffer.
Definition: avio.h:226
avio_rl64
uint64_t avio_rl64(AVIOContext *s)
Definition: aviobuf.c:750
AVIO_ENTRY_SERVER
@ AVIO_ENTRY_SERVER
Definition: avio.h:75
AVIOContext::read_seek
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:257
AVIODirContext::url_context
struct URLContext * url_context
Definition: avio.h:104
avio_put_str16le
int avio_put_str16le(AVIOContext *s, const char *str)
Convert an UTF-8 string to UTF-16LE and write it.
convert_header.str
string str
Definition: convert_header.py:20
avio_wb16
void avio_wb16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:457
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
h
h
Definition: vp9dsp_template.c:2038
avio_wl24
void avio_wl24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:463
AVIOContext::buffer_size
int buffer_size
Maximum buffer size.
Definition: avio.h:227
avio_open_dir
int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options)
Open directory for reading.
Definition: avio.c:531
AVIOContext::buf_ptr
unsigned char * buf_ptr
Current position in the buffer.
Definition: avio.h:228
avio_put_str
int avio_put_str(AVIOContext *s, const char *str)
Write a NULL-terminated string.
Definition: aviobuf.c:387
int
int
Definition: ffmpeg_filter.c:156
avio_read_partial
int avio_read_partial(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:696
AVIOContext::av_class
const AVClass * av_class
A class for private options.
Definition: avio.h:174
AVIO_ENTRY_SHARE
@ AVIO_ENTRY_SHARE
Definition: avio.h:76
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:360
AVIO_DATA_MARKER_FLUSH_POINT
@ AVIO_DATA_MARKER_FLUSH_POINT
A point in the output bytestream where the underlying AVIOContext might flush the buffer depending on...
Definition: avio.h:146