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 #include <stdio.h>
31 
32 #include "libavutil/attributes.h"
33 #include "libavutil/dict.h"
34 #include "libavutil/log.h"
35 
37 
38 /**
39  * Seeking works like for a local file.
40  */
41 #define AVIO_SEEKABLE_NORMAL (1 << 0)
42 
43 /**
44  * Seeking by timestamp with avio_seek_time() is possible.
45  */
46 #define AVIO_SEEKABLE_TIME (1 << 1)
47 
48 /**
49  * Callback for checking whether to abort blocking functions.
50  * AVERROR_EXIT is returned in this case by the interrupted
51  * function. During blocking operations, callback is called with
52  * opaque as parameter. If the callback returns 1, the
53  * blocking operation will be aborted.
54  *
55  * No members can be added to this struct without a major bump, if
56  * new elements have been added after this struct in AVFormatContext
57  * or AVIOContext.
58  */
59 typedef struct AVIOInterruptCB {
60  int (*callback)(void*);
61  void *opaque;
63 
64 /**
65  * Directory entry types.
66  */
79 };
80 
81 /**
82  * Describes single entry of the directory.
83  *
84  * Only name and type fields are guaranteed be set.
85  * Rest of fields are protocol or/and platform dependent and might be unknown.
86  */
87 typedef struct AVIODirEntry {
88  char *name; /**< Filename */
89  int type; /**< Type of the entry */
90  int utf8; /**< Set to 1 when name is encoded with UTF-8, 0 otherwise.
91  Name can be encoded with UTF-8 even though 0 is set. */
92  int64_t size; /**< File size in bytes, -1 if unknown. */
93  int64_t modification_timestamp; /**< Time of last modification in microseconds since unix
94  epoch, -1 if unknown. */
95  int64_t access_timestamp; /**< Time of last access in microseconds since unix epoch,
96  -1 if unknown. */
97  int64_t status_change_timestamp; /**< Time of last status change in microseconds since unix
98  epoch, -1 if unknown. */
99  int64_t user_id; /**< User ID of owner, -1 if unknown. */
100  int64_t group_id; /**< Group ID of owner, -1 if unknown. */
101  int64_t filemode; /**< Unix file mode, -1 if unknown. */
102 } AVIODirEntry;
103 
104 typedef struct AVIODirContext AVIODirContext;
105 
106 /**
107  * Different data types that can be returned via the AVIO
108  * write_data_type callback.
109  */
111  /**
112  * Header data; this needs to be present for the stream to be decodeable.
113  */
115  /**
116  * A point in the output bytestream where a decoder can start decoding
117  * (i.e. a keyframe). A demuxer/decoder given the data flagged with
118  * AVIO_DATA_MARKER_HEADER, followed by any AVIO_DATA_MARKER_SYNC_POINT,
119  * should give decodeable results.
120  */
122  /**
123  * A point in the output bytestream where a demuxer can start parsing
124  * (for non self synchronizing bytestream formats). That is, any
125  * non-keyframe packet start point.
126  */
128  /**
129  * This is any, unlabelled data. It can either be a muxer not marking
130  * any positions at all, it can be an actual boundary/sync point
131  * that the muxer chooses not to mark, or a later part of a packet/fragment
132  * that is cut into multiple write callbacks due to limited IO buffer size.
133  */
135  /**
136  * Trailer data, which doesn't contain actual content, but only for
137  * finalizing the output file.
138  */
140  /**
141  * A point in the output bytestream where the underlying AVIOContext might
142  * flush the buffer depending on latency or buffering requirements. Typically
143  * means the end of a packet.
144  */
146 };
147 
148 /**
149  * Bytestream IO Context.
150  * New public fields can be added with minor version bumps.
151  * Removal, reordering and changes to existing public fields require
152  * a major version bump.
153  * sizeof(AVIOContext) must not be used outside libav*.
154  *
155  * @note None of the function pointers in AVIOContext should be called
156  * directly, they should only be set by the client application
157  * when implementing custom I/O. Normally these are set to the
158  * function pointers specified in avio_alloc_context()
159  */
160 typedef struct AVIOContext {
161  /**
162  * A class for private options.
163  *
164  * If this AVIOContext is created by avio_open2(), av_class is set and
165  * passes the options down to protocols.
166  *
167  * If this AVIOContext is manually allocated, then av_class may be set by
168  * the caller.
169  *
170  * warning -- this field can be NULL, be sure to not pass this AVIOContext
171  * to any av_opt_* functions in that case.
172  */
174 
175  /*
176  * The following shows the relationship between buffer, buf_ptr,
177  * buf_ptr_max, buf_end, buf_size, and pos, when reading and when writing
178  * (since AVIOContext is used for both):
179  *
180  **********************************************************************************
181  * READING
182  **********************************************************************************
183  *
184  * | buffer_size |
185  * |---------------------------------------|
186  * | |
187  *
188  * buffer buf_ptr buf_end
189  * +---------------+-----------------------+
190  * |/ / / / / / / /|/ / / / / / /| |
191  * read buffer: |/ / consumed / | to be read /| |
192  * |/ / / / / / / /|/ / / / / / /| |
193  * +---------------+-----------------------+
194  *
195  * pos
196  * +-------------------------------------------+-----------------+
197  * input file: | | |
198  * +-------------------------------------------+-----------------+
199  *
200  *
201  **********************************************************************************
202  * WRITING
203  **********************************************************************************
204  *
205  * | buffer_size |
206  * |--------------------------------------|
207  * | |
208  *
209  * buf_ptr_max
210  * buffer (buf_ptr) buf_end
211  * +-----------------------+--------------+
212  * |/ / / / / / / / / / / /| |
213  * write buffer: | / / to be flushed / / | |
214  * |/ / / / / / / / / / / /| |
215  * +-----------------------+--------------+
216  * buf_ptr can be in this
217  * due to a backward seek
218  *
219  * pos
220  * +-------------+----------------------------------------------+
221  * output file: | | |
222  * +-------------+----------------------------------------------+
223  *
224  */
225  unsigned char *buffer; /**< Start of the buffer. */
226  int buffer_size; /**< Maximum buffer size */
227  unsigned char *buf_ptr; /**< Current position in the buffer */
228  unsigned char *buf_end; /**< End of the data, may be less than
229  buffer+buffer_size if the read function returned
230  less data than requested, e.g. for streams where
231  no more data has been received yet. */
232  void *opaque; /**< A private pointer, passed to the read/write/seek/...
233  functions. */
234  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
235  int (*write_packet)(void *opaque, const uint8_t *buf, int buf_size);
236  int64_t (*seek)(void *opaque, int64_t offset, int whence);
237  int64_t pos; /**< position in the file of the current buffer */
238  int eof_reached; /**< true if was unable to read due to error or eof */
239  int error; /**< contains the error code or 0 if no error happened */
240  int write_flag; /**< true if open for writing */
242  int min_packet_size; /**< Try to buffer at least this amount of data
243  before flushing it. */
244  unsigned long checksum;
245  unsigned char *checksum_ptr;
246  unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
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  * avio_read and avio_write should if possible be satisfied directly
265  * instead of going through a buffer, and avio_seek will always
266  * call the underlying seek function directly.
267  */
268  int direct;
269 
270  /**
271  * ',' separated list of allowed protocols.
272  */
273  const char *protocol_whitelist;
274 
275  /**
276  * ',' separated list of disallowed protocols.
277  */
278  const char *protocol_blacklist;
279 
280  /**
281  * A callback that is used instead of write_packet.
282  */
283  int (*write_data_type)(void *opaque, const uint8_t *buf, int buf_size,
284  enum AVIODataMarkerType type, int64_t time);
285  /**
286  * If set, don't call write_data_type separately for AVIO_DATA_MARKER_BOUNDARY_POINT,
287  * but ignore them and treat them as AVIO_DATA_MARKER_UNKNOWN (to avoid needlessly
288  * small chunks of data returned from the callback).
289  */
291 
292  /**
293  * Maximum reached position before a backward seek in the write buffer,
294  * used keeping track of already written data for a later flush.
295  */
296  unsigned char *buf_ptr_max;
297 
298  /**
299  * Read-only statistic of bytes read for this AVIOContext.
300  */
301  int64_t bytes_read;
302 
303  /**
304  * Read-only statistic of bytes written for this AVIOContext.
305  */
306  int64_t bytes_written;
307 } AVIOContext;
308 
309 /**
310  * Return the name of the protocol that will handle the passed URL.
311  *
312  * NULL is returned if no protocol could be found for the given URL.
313  *
314  * @return Name of the protocol or NULL.
315  */
316 const char *avio_find_protocol_name(const char *url);
317 
318 /**
319  * Return AVIO_FLAG_* access flags corresponding to the access permissions
320  * of the resource in url, or a negative value corresponding to an
321  * AVERROR code in case of failure. The returned access flags are
322  * masked by the value in flags.
323  *
324  * @note This function is intrinsically unsafe, in the sense that the
325  * checked resource may change its existence or permission status from
326  * one call to another. Thus you should not trust the returned value,
327  * unless you are sure that no other processes are accessing the
328  * checked resource.
329  */
330 int avio_check(const char *url, int flags);
331 
332 /**
333  * Open directory for reading.
334  *
335  * @param s directory read context. Pointer to a NULL pointer must be passed.
336  * @param url directory to be listed.
337  * @param options A dictionary filled with protocol-private options. On return
338  * this parameter will be destroyed and replaced with a dictionary
339  * containing options that were not found. May be NULL.
340  * @return >=0 on success or negative on error.
341  */
342 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
343 
344 /**
345  * Get next directory entry.
346  *
347  * Returned entry must be freed with avio_free_directory_entry(). In particular
348  * it may outlive AVIODirContext.
349  *
350  * @param s directory read context.
351  * @param[out] next next entry or NULL when no more entries.
352  * @return >=0 on success or negative on error. End of list is not considered an
353  * error.
354  */
356 
357 /**
358  * Close directory.
359  *
360  * @note Entries created using avio_read_dir() are not deleted and must be
361  * freeded with avio_free_directory_entry().
362  *
363  * @param s directory read context.
364  * @return >=0 on success or negative on error.
365  */
367 
368 /**
369  * Free entry allocated by avio_read_dir().
370  *
371  * @param entry entry to be freed.
372  */
374 
375 /**
376  * Allocate and initialize an AVIOContext for buffered I/O. It must be later
377  * freed with avio_context_free().
378  *
379  * @param buffer Memory block for input/output operations via AVIOContext.
380  * The buffer must be allocated with av_malloc() and friends.
381  * It may be freed and replaced with a new buffer by libavformat.
382  * AVIOContext.buffer holds the buffer currently in use,
383  * which must be later freed with av_free().
384  * @param buffer_size The buffer size is very important for performance.
385  * For protocols with fixed blocksize it should be set to this blocksize.
386  * For others a typical size is a cache page, e.g. 4kb.
387  * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
388  * @param opaque An opaque pointer to user-specific data.
389  * @param read_packet A function for refilling the buffer, may be NULL.
390  * For stream protocols, must never return 0 but rather
391  * a proper AVERROR code.
392  * @param write_packet A function for writing the buffer contents, may be NULL.
393  * The function may not change the input buffers content.
394  * @param seek A function for seeking to specified byte position, may be NULL.
395  *
396  * @return Allocated AVIOContext or NULL on failure.
397  */
399  unsigned char *buffer,
400  int buffer_size,
401  int write_flag,
402  void *opaque,
403  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
404  int (*write_packet)(void *opaque, const uint8_t *buf, int buf_size),
405  int64_t (*seek)(void *opaque, int64_t offset, int whence));
406 
407 /**
408  * Free the supplied IO context and everything associated with it.
409  *
410  * @param s Double pointer to the IO context. This function will write NULL
411  * into s.
412  */
414 
415 void avio_w8(AVIOContext *s, int b);
416 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
417 void avio_wl64(AVIOContext *s, uint64_t val);
418 void avio_wb64(AVIOContext *s, uint64_t val);
419 void avio_wl32(AVIOContext *s, unsigned int val);
420 void avio_wb32(AVIOContext *s, unsigned int val);
421 void avio_wl24(AVIOContext *s, unsigned int val);
422 void avio_wb24(AVIOContext *s, unsigned int val);
423 void avio_wl16(AVIOContext *s, unsigned int val);
424 void avio_wb16(AVIOContext *s, unsigned int val);
425 
426 /**
427  * Write a NULL-terminated string.
428  * @return number of bytes written.
429  */
430 int avio_put_str(AVIOContext *s, const char *str);
431 
432 /**
433  * Convert an UTF-8 string to UTF-16LE and write it.
434  * @param s the AVIOContext
435  * @param str NULL-terminated UTF-8 string
436  *
437  * @return number of bytes written.
438  */
439 int avio_put_str16le(AVIOContext *s, const char *str);
440 
441 /**
442  * Convert an UTF-8 string to UTF-16BE and write it.
443  * @param s the AVIOContext
444  * @param str NULL-terminated UTF-8 string
445  *
446  * @return number of bytes written.
447  */
448 int avio_put_str16be(AVIOContext *s, const char *str);
449 
450 /**
451  * Mark the written bytestream as a specific type.
452  *
453  * Zero-length ranges are omitted from the output.
454  *
455  * @param s the AVIOContext
456  * @param time the stream time the current bytestream pos corresponds to
457  * (in AV_TIME_BASE units), or AV_NOPTS_VALUE if unknown or not
458  * applicable
459  * @param type the kind of data written starting at the current pos
460  */
461 void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type);
462 
463 /**
464  * ORing this as the "whence" parameter to a seek function causes it to
465  * return the filesize without seeking anywhere. Supporting this is optional.
466  * If it is not supported then the seek function will return <0.
467  */
468 #define AVSEEK_SIZE 0x10000
469 
470 /**
471  * Passing this flag as the "whence" parameter to a seek function causes it to
472  * seek by any means (like reopening and linear reading) or other normally unreasonable
473  * means that can be extremely slow.
474  * This may be ignored by the seek code.
475  */
476 #define AVSEEK_FORCE 0x20000
477 
478 /**
479  * fseek() equivalent for AVIOContext.
480  * @return new position or AVERROR.
481  */
482 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
483 
484 /**
485  * Skip given number of bytes forward
486  * @return new position or AVERROR.
487  */
488 int64_t avio_skip(AVIOContext *s, int64_t offset);
489 
490 /**
491  * ftell() equivalent for AVIOContext.
492  * @return position or AVERROR.
493  */
495 {
496  return avio_seek(s, 0, SEEK_CUR);
497 }
498 
499 /**
500  * Get the filesize.
501  * @return filesize or AVERROR
502  */
503 int64_t avio_size(AVIOContext *s);
504 
505 /**
506  * Similar to feof() but also returns nonzero on read errors.
507  * @return non zero if and only if at end of file or a read error happened when reading.
508  */
509 int avio_feof(AVIOContext *s);
510 
511 /**
512  * Writes a formatted string to the context taking a va_list.
513  * @return number of bytes written, < 0 on error.
514  */
515 int avio_vprintf(AVIOContext *s, const char *fmt, va_list ap);
516 
517 /**
518  * Writes a formatted string to the context.
519  * @return number of bytes written, < 0 on error.
520  */
521 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
522 
523 /**
524  * Write a NULL terminated array of strings to the context.
525  * Usually you don't need to use this function directly but its macro wrapper,
526  * avio_print.
527  */
528 void avio_print_string_array(AVIOContext *s, const char * const strings[]);
529 
530 /**
531  * Write strings (const char *) to the context.
532  * This is a convenience macro around avio_print_string_array and it
533  * automatically creates the string array from the variable argument list.
534  * For simple string concatenations this function is more performant than using
535  * avio_printf since it does not need a temporary buffer.
536  */
537 #define avio_print(s, ...) \
538  avio_print_string_array(s, (const char*[]){__VA_ARGS__, NULL})
539 
540 /**
541  * Force flushing of buffered data.
542  *
543  * For write streams, force the buffered data to be immediately written to the output,
544  * without to wait to fill the internal buffer.
545  *
546  * For read streams, discard all currently buffered data, and advance the
547  * reported file position to that of the underlying stream. This does not
548  * read new data, and does not perform any seeks.
549  */
550 void avio_flush(AVIOContext *s);
551 
552 /**
553  * Read size bytes from AVIOContext into buf.
554  * @return number of bytes read or AVERROR
555  */
556 int avio_read(AVIOContext *s, unsigned char *buf, int size);
557 
558 /**
559  * Read size bytes from AVIOContext into buf. Unlike avio_read(), this is allowed
560  * to read fewer bytes than requested. The missing bytes can be read in the next
561  * call. This always tries to read at least 1 byte.
562  * Useful to reduce latency in certain cases.
563  * @return number of bytes read or AVERROR
564  */
565 int avio_read_partial(AVIOContext *s, unsigned char *buf, int size);
566 
567 /**
568  * @name Functions for reading from AVIOContext
569  * @{
570  *
571  * @note return 0 if EOF, so you cannot use it if EOF handling is
572  * necessary
573  */
574 int avio_r8 (AVIOContext *s);
575 unsigned int avio_rl16(AVIOContext *s);
576 unsigned int avio_rl24(AVIOContext *s);
577 unsigned int avio_rl32(AVIOContext *s);
578 uint64_t avio_rl64(AVIOContext *s);
579 unsigned int avio_rb16(AVIOContext *s);
580 unsigned int avio_rb24(AVIOContext *s);
581 unsigned int avio_rb32(AVIOContext *s);
582 uint64_t avio_rb64(AVIOContext *s);
583 /**
584  * @}
585  */
586 
587 /**
588  * Read a string from pb into buf. The reading will terminate when either
589  * a NULL character was encountered, maxlen bytes have been read, or nothing
590  * more can be read from pb. The result is guaranteed to be NULL-terminated, it
591  * will be truncated if buf is too small.
592  * Note that the string is not interpreted or validated in any way, it
593  * might get truncated in the middle of a sequence for multi-byte encodings.
594  *
595  * @return number of bytes read (is always <= maxlen).
596  * If reading ends on EOF or error, the return value will be one more than
597  * bytes actually read.
598  */
599 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
600 
601 /**
602  * Read a UTF-16 string from pb and convert it to UTF-8.
603  * The reading will terminate when either a null or invalid character was
604  * encountered or maxlen bytes have been read.
605  * @return number of bytes read (is always <= maxlen)
606  */
607 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
608 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
609 
610 
611 /**
612  * @name URL open modes
613  * The flags argument to avio_open must be one of the following
614  * constants, optionally ORed with other flags.
615  * @{
616  */
617 #define AVIO_FLAG_READ 1 /**< read-only */
618 #define AVIO_FLAG_WRITE 2 /**< write-only */
619 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
620 /**
621  * @}
622  */
623 
624 /**
625  * Use non-blocking mode.
626  * If this flag is set, operations on the context will return
627  * AVERROR(EAGAIN) if they can not be performed immediately.
628  * If this flag is not set, operations on the context will never return
629  * AVERROR(EAGAIN).
630  * Note that this flag does not affect the opening/connecting of the
631  * context. Connecting a protocol will always block if necessary (e.g. on
632  * network protocols) but never hang (e.g. on busy devices).
633  * Warning: non-blocking protocols is work-in-progress; this flag may be
634  * silently ignored.
635  */
636 #define AVIO_FLAG_NONBLOCK 8
637 
638 /**
639  * Use direct mode.
640  * avio_read and avio_write should if possible be satisfied directly
641  * instead of going through a buffer, and avio_seek will always
642  * call the underlying seek function directly.
643  */
644 #define AVIO_FLAG_DIRECT 0x8000
645 
646 /**
647  * Create and initialize a AVIOContext for accessing the
648  * resource indicated by url.
649  * @note When the resource indicated by url has been opened in
650  * read+write mode, the AVIOContext can be used only for writing.
651  *
652  * @param s Used to return the pointer to the created AVIOContext.
653  * In case of failure the pointed to value is set to NULL.
654  * @param url resource to access
655  * @param flags flags which control how the resource indicated by url
656  * is to be opened
657  * @return >= 0 in case of success, a negative value corresponding to an
658  * AVERROR code in case of failure
659  */
660 int avio_open(AVIOContext **s, const char *url, int flags);
661 
662 /**
663  * Create and initialize a AVIOContext for accessing the
664  * resource indicated by url.
665  * @note When the resource indicated by url has been opened in
666  * read+write mode, the AVIOContext can be used only for writing.
667  *
668  * @param s Used to return the pointer to the created AVIOContext.
669  * In case of failure the pointed to value is set to NULL.
670  * @param url resource to access
671  * @param flags flags which control how the resource indicated by url
672  * is to be opened
673  * @param int_cb an interrupt callback to be used at the protocols level
674  * @param options A dictionary filled with protocol-private options. On return
675  * this parameter will be destroyed and replaced with a dict containing options
676  * that were not found. May be NULL.
677  * @return >= 0 in case of success, a negative value corresponding to an
678  * AVERROR code in case of failure
679  */
680 int avio_open2(AVIOContext **s, const char *url, int flags,
682 
683 /**
684  * Close the resource accessed by the AVIOContext s and free it.
685  * This function can only be used if s was opened by avio_open().
686  *
687  * The internal buffer is automatically flushed before closing the
688  * resource.
689  *
690  * @return 0 on success, an AVERROR < 0 on error.
691  * @see avio_closep
692  */
693 int avio_close(AVIOContext *s);
694 
695 /**
696  * Close the resource accessed by the AVIOContext *s, free it
697  * and set the pointer pointing to it to NULL.
698  * This function can only be used if s was opened by avio_open().
699  *
700  * The internal buffer is automatically flushed before closing the
701  * resource.
702  *
703  * @return 0 on success, an AVERROR < 0 on error.
704  * @see avio_close
705  */
706 int avio_closep(AVIOContext **s);
707 
708 
709 /**
710  * Open a write only memory stream.
711  *
712  * @param s new IO context
713  * @return zero if no error.
714  */
716 
717 /**
718  * Return the written size and a pointer to the buffer.
719  * The AVIOContext stream is left intact.
720  * The buffer must NOT be freed.
721  * No padding is added to the buffer.
722  *
723  * @param s IO context
724  * @param pbuffer pointer to a byte buffer
725  * @return the length of the byte buffer
726  */
727 int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
728 
729 /**
730  * Return the written size and a pointer to the buffer. The buffer
731  * must be freed with av_free().
732  * Padding of AV_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
733  *
734  * @param s IO context
735  * @param pbuffer pointer to a byte buffer
736  * @return the length of the byte buffer
737  */
738 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
739 
740 /**
741  * Iterate through names of available protocols.
742  *
743  * @param opaque A private pointer representing current protocol.
744  * It must be a pointer to NULL on first iteration and will
745  * be updated by successive calls to avio_enum_protocols.
746  * @param output If set to 1, iterate over output protocols,
747  * otherwise over input protocols.
748  *
749  * @return A static string containing the name of current protocol or NULL
750  */
751 const char *avio_enum_protocols(void **opaque, int output);
752 
753 /**
754  * Get AVClass by names of available protocols.
755  *
756  * @return A AVClass of input protocol name or NULL
757  */
758 const AVClass *avio_protocol_get_class(const char *name);
759 
760 /**
761  * Pause and resume playing - only meaningful if using a network streaming
762  * protocol (e.g. MMS).
763  *
764  * @param h IO context from which to call the read_pause function pointer
765  * @param pause 1 for pause, 0 for resume
766  */
767 int avio_pause(AVIOContext *h, int pause);
768 
769 /**
770  * Seek to a given timestamp relative to some component stream.
771  * Only meaningful if using a network streaming protocol (e.g. MMS.).
772  *
773  * @param h IO context from which to call the seek function pointers
774  * @param stream_index The stream index that the timestamp is relative to.
775  * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
776  * units from the beginning of the presentation.
777  * If a stream_index >= 0 is used and the protocol does not support
778  * seeking based on component streams, the call will fail.
779  * @param timestamp timestamp in AVStream.time_base units
780  * or if there is no stream specified then in AV_TIME_BASE units.
781  * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
782  * and AVSEEK_FLAG_ANY. The protocol may silently ignore
783  * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
784  * fail if used and not supported.
785  * @return >= 0 on success
786  * @see AVInputFormat::read_seek
787  */
788 int64_t avio_seek_time(AVIOContext *h, int stream_index,
789  int64_t timestamp, int flags);
790 
791 /* Avoid a warning. The header can not be included because it breaks c++. */
792 struct AVBPrint;
793 
794 /**
795  * Read contents of h into print buffer, up to max_size bytes, or up to EOF.
796  *
797  * @return 0 for success (max_size bytes read or EOF reached), negative error
798  * code otherwise
799  */
800 int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
801 
802 /**
803  * Accept and allocate a client context on a server context.
804  * @param s the server context
805  * @param c the client context, must be unallocated
806  * @return >= 0 on success or a negative value corresponding
807  * to an AVERROR on failure
808  */
810 
811 /**
812  * Perform one step of the protocol handshake to accept a new client.
813  * This function must be called on a client returned by avio_accept() before
814  * using it as a read/write context.
815  * It is separate from avio_accept() because it may block.
816  * A step of the handshake is defined by places where the application may
817  * decide to change the proceedings.
818  * For example, on a protocol with a request header and a reply header, each
819  * one can constitute a step because the application may use the parameters
820  * from the request to change parameters in the reply; or each individual
821  * chunk of the request can constitute a step.
822  * If the handshake is already finished, avio_handshake() does nothing and
823  * returns 0 immediately.
824  *
825  * @param c the client context to perform the handshake on
826  * @return 0 on a complete and successful handshake
827  * > 0 if the handshake progressed, but is not complete
828  * < 0 for an AVERROR code
829  */
831 #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:127
avio_protocol_get_class
const AVClass * avio_protocol_get_class(const char *name)
Get AVClass by names of available protocols.
Definition: protocols.c:113
AVIOContext::seek
int64_t(* seek)(void *opaque, int64_t offset, int whence)
Definition: avio.h:236
avio_close
int avio_close(AVIOContext *s)
Close the resource accessed by the AVIOContext s and free it.
Definition: avio.c:615
avio_context_free
void avio_context_free(AVIOContext **s)
Free the supplied IO context and everything associated with it.
Definition: aviobuf.c:125
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:90
AVIOContext::protocol_blacklist
const char * protocol_blacklist
',' separated list of disallowed protocols.
Definition: avio.h:278
AVIODirEntry::type
int type
Type of the entry.
Definition: avio.h:89
avio_read_dir
int avio_read_dir(AVIODirContext *s, AVIODirEntry **next)
Get next directory entry.
Definition: avio.c:762
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, const 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:108
b
#define b
Definition: input.c:41
AVIO_ENTRY_NAMED_PIPE
@ AVIO_ENTRY_NAMED_PIPE
Definition: avio.h:72
avio_enum_protocols
const char * avio_enum_protocols(void **opaque, int output)
Iterate through names of available protocols.
Definition: protocols.c:98
AVIOContext::error
int error
contains the error code or 0 if no error happened
Definition: avio.h:239
avio_wl64
void avio_wl64(AVIOContext *s, uint64_t val)
Definition: aviobuf.c:424
AVIOContext::max_packet_size
int max_packet_size
Definition: avio.h:241
AVDictionary
Definition: dict.c:34
AVIODataMarkerType
AVIODataMarkerType
Different data types that can be returned via the AVIO write_data_type callback.
Definition: avio.h:110
avio_size
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:322
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:1373
AVIO_ENTRY_UNKNOWN
@ AVIO_ENTRY_UNKNOWN
Definition: avio.h:68
AVIOInterruptCB
Callback for checking whether to abort blocking functions.
Definition: avio.h:59
AVIODirEntry::access_timestamp
int64_t access_timestamp
Time of last access in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:95
avio_print_string_array
int void avio_print_string_array(AVIOContext *s, const char *const strings[])
Write a NULL terminated array of strings to the context.
Definition: aviobuf.c:1218
avio_wl16
void avio_wl16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:436
avio_handshake
int avio_handshake(AVIOContext *c)
Perform one step of the protocol handshake to accept a new client.
Definition: avio.c:295
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:460
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: avio.c:490
avio_close_dir
int avio_close_dir(AVIODirContext **s)
Close directory.
Definition: avio.c:775
AVIO_ENTRY_DIRECTORY
@ AVIO_ENTRY_DIRECTORY
Definition: avio.h:71
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:1231
AVIOContext::write_data_type
int(* write_data_type)(void *opaque, const uint8_t *buf, int buf_size, enum AVIODataMarkerType type, int64_t time)
A callback that is used instead of write_packet.
Definition: avio.h:283
AVIO_ENTRY_CHARACTER_DEVICE
@ AVIO_ENTRY_CHARACTER_DEVICE
Definition: avio.h:70
AVIOContext::pos
int64_t pos
position in the file of the current buffer
Definition: avio.h:237
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:494
val
static double val(void *priv, double ch)
Definition: aeval.c:78
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:713
AVIODirEntry::modification_timestamp
int64_t modification_timestamp
Time of last modification in microseconds since unix epoch, -1 if unknown.
Definition: avio.h:93
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:1406
avio_rb32
unsigned int avio_rb32(AVIOContext *s)
Definition: aviobuf.c:760
AVIO_ENTRY_SYMBOLIC_LINK
@ AVIO_ENTRY_SYMBOLIC_LINK
Definition: avio.h:73
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_read_callback.c:41
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:1361
s
#define s(width, name)
Definition: cbs_vp9.c:198
avio_free_directory_entry
void avio_free_directory_entry(AVIODirEntry **entry)
Free entry allocated by avio_read_dir().
Definition: avio.c:790
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:1250
version_major.h
AVIOContext::write_flag
int write_flag
true if open for writing
Definition: avio.h:240
avio_flush
void avio_flush(AVIOContext *s)
Force flushing of buffered data.
Definition: aviobuf.c:222
AVIODirEntryType
AVIODirEntryType
Directory entry types.
Definition: avio.h:67
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:242
AVIODirEntry::size
int64_t size
File size in bytes, -1 if unknown.
Definition: avio.h:92
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:139
AVIOContext::read_pause
int(* read_pause)(void *opaque, int pause)
Pause or resume playback for network streaming protocols - e.g.
Definition: avio.h:250
AVIODirEntry::name
char * name
Filename.
Definition: avio.h:88
avio_rb64
uint64_t avio_rb64(AVIOContext *s)
Definition: aviobuf.c:907
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: avio.c:272
AVIO_ENTRY_FILE
@ AVIO_ENTRY_FILE
Definition: avio.h:75
seek
static void BS_FUNC() seek(BSCTX *bc, unsigned pos)
Seek to the given bit position.
Definition: bitstream_template.h:399
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:1224
avio_w8
void avio_w8(AVIOContext *s, int b)
Definition: aviobuf.c:178
AVIODirEntry::group_id
int64_t group_id
Group ID of owner, -1 if unknown.
Definition: avio.h:100
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:101
AVIOContext::protocol_whitelist
const char * protocol_whitelist
',' separated list of allowed protocols.
Definition: avio.h:273
options
const OptionDef options[]
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:729
AVIOContext
Bytestream IO Context.
Definition: avio.h:160
avio_rb24
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:753
AVIOContext::seekable
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:261
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:228
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:865
size
int size
Definition: twinvq_data.h:10344
AVIODirEntry
Describes single entry of the directory.
Definition: avio.h:87
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:121
avio_write
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:200
avio_wb32
void avio_wb32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:364
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:602
avio_wl32
void avio_wl32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:356
AVIOContext::bytes_written
int64_t bytes_written
Read-only statistic of bytes written for this AVIOContext.
Definition: avio.h:306
AVIOContext::checksum_ptr
unsigned char * checksum_ptr
Definition: avio.h:245
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
attributes.h
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:97
AVIO_ENTRY_SOCKET
@ AVIO_ENTRY_SOCKET
Definition: avio.h:74
AVIODirEntry::user_id
int64_t user_id
User ID of owner, -1 if unknown.
Definition: avio.h:99
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: avio.c:648
AVIOContext::opaque
void * opaque
A private pointer, passed to the read/write/seek/...
Definition: avio.h:232
AVIOContext::bytes_read
int64_t bytes_read
Read-only statistic of bytes read for this AVIOContext.
Definition: avio.h:301
AVIOContext::direct
int direct
avio_read and avio_write should if possible be satisfied directly instead of going through a buffer,...
Definition: avio.h:268
log.h
avio_rl24
unsigned int avio_rl24(AVIOContext *s)
Definition: aviobuf.c:721
av_always_inline
#define av_always_inline
Definition: attributes.h:49
int_cb
const AVIOInterruptCB int_cb
Definition: ffmpeg.c:327
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:663
AVIOInterruptCB::opaque
void * opaque
Definition: avio.h:61
write_packet
static int write_packet(Muxer *mux, OutputStream *ost, AVPacket *pkt)
Definition: ffmpeg_mux.c:209
AVIO_DATA_MARKER_UNKNOWN
@ AVIO_DATA_MARKER_UNKNOWN
This is any, unlabelled data.
Definition: avio.h:134
AVIO_ENTRY_BLOCK_DEVICE
@ AVIO_ENTRY_BLOCK_DEVICE
Definition: avio.h:69
AVIOContext::checksum
unsigned long checksum
Definition: avio.h:244
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:230
AVIODirContext
Definition: avio.c:720
avio_rb16
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:745
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:290
dict.h
avio_vprintf
int avio_vprintf(AVIOContext *s, const char *fmt, va_list ap)
Writes a formatted string to the context taking a va_list.
Definition: aviobuf.c:1190
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:296
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:246
AVIO_DATA_MARKER_HEADER
@ AVIO_DATA_MARKER_HEADER
Header data; this needs to be present for the stream to be decodeable.
Definition: avio.h:114
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:611
AVIOContext::eof_reached
int eof_reached
true if was unable to read due to error or eof
Definition: avio.h:238
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: avio.c:496
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:317
AVIO_ENTRY_WORKGROUP
@ AVIO_ENTRY_WORKGROUP
Definition: avio.h:78
avio_wb64
void avio_wb64(AVIOContext *s, uint64_t val)
Definition: aviobuf.c:430
AVIOContext::write_packet
int(* write_packet)(void *opaque, const uint8_t *buf, int buf_size)
Definition: avio.h:235
AVIOContext::read_packet
int(* read_packet)(void *opaque, uint8_t *buf, int buf_size)
Definition: avio.h:234
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:656
AVIOInterruptCB::callback
int(* callback)(void *)
Definition: avio.h:60
avio_wb24
void avio_wb24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:454
AVIOContext::buffer
unsigned char * buffer
Start of the buffer.
Definition: avio.h:225
avio_rl64
uint64_t avio_rl64(AVIOContext *s)
Definition: aviobuf.c:737
AVIO_ENTRY_SERVER
@ AVIO_ENTRY_SERVER
Definition: avio.h:76
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:256
avio_put_str16le
int avio_put_str16le(AVIOContext *s, const char *str)
Convert an UTF-8 string to UTF-16LE and write it.
avio_wb16
void avio_wb16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:442
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:474
h
h
Definition: vp9dsp_template.c:2038
avio_wl24
void avio_wl24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:448
AVIOContext::buffer_size
int buffer_size
Maximum buffer size.
Definition: avio.h:226
avio_open_dir
int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options)
Open directory for reading.
Definition: avio.c:724
AVIOContext::buf_ptr
unsigned char * buf_ptr
Current position in the buffer.
Definition: avio.h:227
avio_put_str
int avio_put_str(AVIOContext *s, const char *str)
Write a NULL-terminated string.
Definition: aviobuf.c:372
int
int
Definition: ffmpeg_filter.c:425
avio_read_partial
int avio_read_partial(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:683
AVIOContext::av_class
const AVClass * av_class
A class for private options.
Definition: avio.h:173
AVIO_ENTRY_SHARE
@ AVIO_ENTRY_SHARE
Definition: avio.h:77
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:345
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:145