2 * copyright (c) 2001 Fabrice Bellard
4 * This file is part of FFmpeg.
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.
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.
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
20 #ifndef AVFORMAT_AVIO_H
21 #define AVFORMAT_AVIO_H
26 * Buffered I/O operations
31 #include "libavutil/common.h"
32 #include "libavutil/dict.h"
33 #include "libavutil/log.h"
35 #include "libavformat/version.h"
38 #define AVIO_SEEKABLE_NORMAL 0x0001 /**< Seeking works like for a local file */
41 * Callback for checking whether to abort blocking functions.
42 * AVERROR_EXIT is returned in this case by the interrupted
43 * function. During blocking operations, callback is called with
44 * opaque as parameter. If the callback returns 1, the
45 * blocking operation will be aborted.
47 * No members can be added to this struct without a major bump, if
48 * new elements have been added after this struct in AVFormatContext
52 int (*callback)(void*);
57 * Bytestream IO Context.
58 * New fields can be added to the end with minor version bumps.
59 * Removal, reordering and changes to existing fields require a major
61 * sizeof(AVIOContext) must not be used outside libav*.
63 * @note None of the function pointers in AVIOContext should be called
64 * directly, they should only be set by the client application
65 * when implementing custom I/O. Normally these are set to the
66 * function pointers specified in avio_alloc_context()
71 * A class for private options.
73 * If this AVIOContext is created by avio_open2(), av_class is set and
74 * passes the options down to protocols.
76 * If this AVIOContext is manually allocated, then av_class may be set by
79 * warning -- this field can be NULL, be sure to not pass this AVIOContext
80 * to any av_opt_* functions in that case.
84 unsigned char *buffer; /**< Start of the buffer. */
85 int buffer_size; /**< Maximum buffer size */
86 unsigned char *buf_ptr; /**< Current position in the buffer */
87 unsigned char *buf_end; /**< End of the data, may be less than
88 buffer+buffer_size if the read function returned
89 less data than requested, e.g. for streams where
90 no more data has been received yet. */
91 void *opaque; /**< A private pointer, passed to the read/write/seek/...
93 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
94 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
95 int64_t (*seek)(void *opaque, int64_t offset, int whence);
96 int64_t pos; /**< position in the file of the current buffer */
97 int must_flush; /**< true if the next seek should flush */
98 int eof_reached; /**< true if eof reached */
99 int write_flag; /**< true if open for writing */
101 attribute_deprecated int is_streamed;
104 unsigned long checksum;
105 unsigned char *checksum_ptr;
106 unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
107 int error; /**< contains the error code or 0 if no error happened */
109 * Pause or resume playback for network streaming protocols - e.g. MMS.
111 int (*read_pause)(void *opaque, int pause);
113 * Seek to a given timestamp in stream with the specified stream_index.
114 * Needed for some network streaming protocols which don't support seeking
117 int64_t (*read_seek)(void *opaque, int stream_index,
118 int64_t timestamp, int flags);
120 * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
130 * New fields can be added to the end with minor version bumps.
131 * Removal, reordering and changes to existing fields require a major
133 * sizeof(URLContext) must not be used outside libav*.
134 * @deprecated This struct will be made private
136 typedef struct URLContext {
137 const AVClass *av_class; ///< information for av_log(). Set by url_open().
138 struct URLProtocol *prot;
140 int is_streamed; /**< true if streamed (no seek possible), default = false */
141 int max_packet_size; /**< if non zero, the stream is packetized with this max packet size */
143 char *filename; /**< specified URL */
145 AVIOInterruptCB interrupt_callback;
148 #define URL_PROTOCOL_FLAG_NESTED_SCHEME 1 /*< The protocol name can be the first part of a nested protocol scheme */
151 * @deprecated This struct is to be made private. Use the higher-level
152 * AVIOContext-based API instead.
154 typedef struct URLProtocol {
156 int (*url_open)(URLContext *h, const char *url, int flags);
157 int (*url_read)(URLContext *h, unsigned char *buf, int size);
158 int (*url_write)(URLContext *h, const unsigned char *buf, int size);
159 int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
160 int (*url_close)(URLContext *h);
161 struct URLProtocol *next;
162 int (*url_read_pause)(URLContext *h, int pause);
163 int64_t (*url_read_seek)(URLContext *h, int stream_index,
164 int64_t timestamp, int flags);
165 int (*url_get_file_handle)(URLContext *h);
167 const AVClass *priv_data_class;
169 int (*url_check)(URLContext *h, int mask);
172 typedef struct URLPollEntry {
178 /* not implemented */
179 attribute_deprecated int url_poll(URLPollEntry *poll_table, int n, int timeout);
182 * @name URL open modes
183 * The flags argument to url_open and cosins must be one of the following
184 * constants, optionally ORed with other flags.
187 #define URL_RDONLY 1 /**< read-only */
188 #define URL_WRONLY 2 /**< write-only */
189 #define URL_RDWR (URL_RDONLY|URL_WRONLY) /**< read-write */
195 * Use non-blocking mode.
196 * If this flag is set, operations on the context will return
197 * AVERROR(EAGAIN) if they can not be performed immediately.
198 * If this flag is not set, operations on the context will never return
200 * Note that this flag does not affect the opening/connecting of the
201 * context. Connecting a protocol will always block if necessary (e.g. on
202 * network protocols) but never hang (e.g. on busy devices).
203 * Warning: non-blocking protocols is work-in-progress; this flag may be
206 #define URL_FLAG_NONBLOCK 4
208 typedef int URLInterruptCB(void);
209 extern URLInterruptCB *url_interrupt_cb;
212 * @defgroup old_url_funcs Old url_* functions
213 * The following functions are deprecated. Use the buffered API based on #AVIOContext instead.
217 attribute_deprecated int url_open_protocol (URLContext **puc, struct URLProtocol *up,
218 const char *url, int flags);
219 attribute_deprecated int url_alloc(URLContext **h, const char *url, int flags);
220 attribute_deprecated int url_connect(URLContext *h);
221 attribute_deprecated int url_open(URLContext **h, const char *url, int flags);
222 attribute_deprecated int url_read(URLContext *h, unsigned char *buf, int size);
223 attribute_deprecated int url_read_complete(URLContext *h, unsigned char *buf, int size);
224 attribute_deprecated int url_write(URLContext *h, const unsigned char *buf, int size);
225 attribute_deprecated int64_t url_seek(URLContext *h, int64_t pos, int whence);
226 attribute_deprecated int url_close(URLContext *h);
227 attribute_deprecated int64_t url_filesize(URLContext *h);
228 attribute_deprecated int url_get_file_handle(URLContext *h);
229 attribute_deprecated int url_get_max_packet_size(URLContext *h);
230 attribute_deprecated void url_get_filename(URLContext *h, char *buf, int buf_size);
231 attribute_deprecated int av_url_read_pause(URLContext *h, int pause);
232 attribute_deprecated int64_t av_url_read_seek(URLContext *h, int stream_index,
233 int64_t timestamp, int flags);
234 attribute_deprecated void url_set_interrupt_cb(int (*interrupt_cb)(void));
237 * returns the next registered protocol after the given protocol (the first if
238 * NULL is given), or NULL if protocol is the last one.
240 URLProtocol *av_protocol_next(URLProtocol *p);
243 * Register the URLProtocol protocol.
245 * @param size the size of the URLProtocol struct referenced
247 attribute_deprecated int av_register_protocol2(URLProtocol *protocol, int size);
253 typedef attribute_deprecated AVIOContext ByteIOContext;
255 attribute_deprecated int init_put_byte(AVIOContext *s,
256 unsigned char *buffer,
260 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
261 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
262 int64_t (*seek)(void *opaque, int64_t offset, int whence));
263 attribute_deprecated AVIOContext *av_alloc_put_byte(
264 unsigned char *buffer,
268 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
269 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
270 int64_t (*seek)(void *opaque, int64_t offset, int whence));
273 * @defgroup old_avio_funcs Old put_/get_*() functions
274 * The following functions are deprecated. Use the "avio_"-prefixed functions instead.
278 attribute_deprecated int get_buffer(AVIOContext *s, unsigned char *buf, int size);
279 attribute_deprecated int get_partial_buffer(AVIOContext *s, unsigned char *buf, int size);
280 attribute_deprecated int get_byte(AVIOContext *s);
281 attribute_deprecated unsigned int get_le16(AVIOContext *s);
282 attribute_deprecated unsigned int get_le24(AVIOContext *s);
283 attribute_deprecated unsigned int get_le32(AVIOContext *s);
284 attribute_deprecated uint64_t get_le64(AVIOContext *s);
285 attribute_deprecated unsigned int get_be16(AVIOContext *s);
286 attribute_deprecated unsigned int get_be24(AVIOContext *s);
287 attribute_deprecated unsigned int get_be32(AVIOContext *s);
288 attribute_deprecated uint64_t get_be64(AVIOContext *s);
290 attribute_deprecated void put_byte(AVIOContext *s, int b);
291 attribute_deprecated void put_nbyte(AVIOContext *s, int b, int count);
292 attribute_deprecated void put_buffer(AVIOContext *s, const unsigned char *buf, int size);
293 attribute_deprecated void put_le64(AVIOContext *s, uint64_t val);
294 attribute_deprecated void put_be64(AVIOContext *s, uint64_t val);
295 attribute_deprecated void put_le32(AVIOContext *s, unsigned int val);
296 attribute_deprecated void put_be32(AVIOContext *s, unsigned int val);
297 attribute_deprecated void put_le24(AVIOContext *s, unsigned int val);
298 attribute_deprecated void put_be24(AVIOContext *s, unsigned int val);
299 attribute_deprecated void put_le16(AVIOContext *s, unsigned int val);
300 attribute_deprecated void put_be16(AVIOContext *s, unsigned int val);
301 attribute_deprecated void put_tag(AVIOContext *s, const char *tag);
306 attribute_deprecated int av_url_read_fpause(AVIOContext *h, int pause);
307 attribute_deprecated int64_t av_url_read_fseek (AVIOContext *h, int stream_index,
308 int64_t timestamp, int flags);
311 * @defgroup old_url_f_funcs Old url_f* functions
312 * The following functions are deprecated, use the "avio_"-prefixed functions instead.
316 attribute_deprecated int url_fopen( AVIOContext **s, const char *url, int flags);
317 attribute_deprecated int url_fclose(AVIOContext *s);
318 attribute_deprecated int64_t url_fseek(AVIOContext *s, int64_t offset, int whence);
319 attribute_deprecated int url_fskip(AVIOContext *s, int64_t offset);
320 attribute_deprecated int64_t url_ftell(AVIOContext *s);
321 attribute_deprecated int64_t url_fsize(AVIOContext *s);
323 attribute_deprecated int url_fgetc(AVIOContext *s);
324 attribute_deprecated int url_setbufsize(AVIOContext *s, int buf_size);
325 attribute_deprecated int url_fprintf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
326 attribute_deprecated void put_flush_packet(AVIOContext *s);
327 attribute_deprecated int url_open_dyn_buf(AVIOContext **s);
328 attribute_deprecated int url_open_dyn_packet_buf(AVIOContext **s, int max_packet_size);
329 attribute_deprecated int url_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
330 attribute_deprecated int url_fdopen(AVIOContext **s, URLContext *h);
335 attribute_deprecated int url_ferror(AVIOContext *s);
337 attribute_deprecated int udp_set_remote_url(URLContext *h, const char *uri);
338 attribute_deprecated int udp_get_local_port(URLContext *h);
340 attribute_deprecated void init_checksum(AVIOContext *s,
341 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
342 unsigned long checksum);
343 attribute_deprecated unsigned long get_checksum(AVIOContext *s);
344 attribute_deprecated void put_strz(AVIOContext *s, const char *buf);
345 /** @note unlike fgets, the EOL character is not returned and a whole
346 line is parsed. return NULL if first char read was EOF */
347 attribute_deprecated char *url_fgets(AVIOContext *s, char *buf, int buf_size);
349 * @deprecated use avio_get_str instead
351 attribute_deprecated char *get_strz(AVIOContext *s, char *buf, int maxlen);
353 * @deprecated Use AVIOContext.seekable field directly.
355 attribute_deprecated static inline int url_is_streamed(AVIOContext *s)
359 attribute_deprecated URLContext *url_fileno(AVIOContext *s);
362 * @deprecated use AVIOContext.max_packet_size directly.
364 attribute_deprecated int url_fget_max_packet_size(AVIOContext *s);
366 attribute_deprecated int url_open_buf(AVIOContext **s, uint8_t *buf, int buf_size, int flags);
368 /** return the written or read size */
369 attribute_deprecated int url_close_buf(AVIOContext *s);
372 * Return a non-zero value if the resource indicated by url
373 * exists, 0 otherwise.
374 * @deprecated Use avio_check instead.
376 attribute_deprecated int url_exist(const char *url);
377 #endif // FF_API_OLD_AVIO
380 * Return AVIO_FLAG_* access flags corresponding to the access permissions
381 * of the resource in url, or a negative value corresponding to an
382 * AVERROR code in case of failure. The returned access flags are
383 * masked by the value in flags.
385 * @note This function is intrinsically unsafe, in the sense that the
386 * checked resource may change its existence or permission status from
387 * one call to another. Thus you should not trust the returned value,
388 * unless you are sure that no other processes are accessing the
391 int avio_check(const char *url, int flags);
393 #if FF_API_OLD_INTERRUPT_CB
395 * The callback is called in blocking functions to test regulary if
396 * asynchronous interruption is needed. AVERROR_EXIT is returned
397 * in this case by the interrupted function. 'NULL' means no interrupt
399 * @deprecated Use interrupt_callback in AVFormatContext/avio_open2
402 attribute_deprecated void avio_set_interrupt_cb(int (*interrupt_cb)(void));
406 * Allocate and initialize an AVIOContext for buffered I/O. It must be later
407 * freed with av_free().
409 * @param buffer Memory block for input/output operations via AVIOContext.
410 * The buffer must be allocated with av_malloc() and friends.
411 * @param buffer_size The buffer size is very important for performance.
412 * For protocols with fixed blocksize it should be set to this blocksize.
413 * For others a typical size is a cache page, e.g. 4kb.
414 * @param write_flag Set to 1 if the buffer should be writable, 0 otherwise.
415 * @param opaque An opaque pointer to user-specific data.
416 * @param read_packet A function for refilling the buffer, may be NULL.
417 * @param write_packet A function for writing the buffer contents, may be NULL.
418 * @param seek A function for seeking to specified byte position, may be NULL.
420 * @return Allocated AVIOContext or NULL on failure.
422 AVIOContext *avio_alloc_context(
423 unsigned char *buffer,
427 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
428 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
429 int64_t (*seek)(void *opaque, int64_t offset, int whence));
431 void avio_w8(AVIOContext *s, int b);
432 void avio_write(AVIOContext *s, const unsigned char *buf, int size);
433 void avio_wl64(AVIOContext *s, uint64_t val);
434 void avio_wb64(AVIOContext *s, uint64_t val);
435 void avio_wl32(AVIOContext *s, unsigned int val);
436 void avio_wb32(AVIOContext *s, unsigned int val);
437 void avio_wl24(AVIOContext *s, unsigned int val);
438 void avio_wb24(AVIOContext *s, unsigned int val);
439 void avio_wl16(AVIOContext *s, unsigned int val);
440 void avio_wb16(AVIOContext *s, unsigned int val);
443 * Write a NULL-terminated string.
444 * @return number of bytes written.
446 int avio_put_str(AVIOContext *s, const char *str);
449 * Convert an UTF-8 string to UTF-16LE and write it.
450 * @return number of bytes written.
452 int avio_put_str16le(AVIOContext *s, const char *str);
455 * Passing this as the "whence" parameter to a seek function causes it to
456 * return the filesize without seeking anywhere. Supporting this is optional.
457 * If it is not supported then the seek function will return <0.
459 #define AVSEEK_SIZE 0x10000
462 * Oring this flag as into the "whence" parameter to a seek function causes it to
463 * seek by any means (like reopening and linear reading) or other normally unreasonble
464 * means that can be extreemly slow.
465 * This may be ignored by the seek code.
467 #define AVSEEK_FORCE 0x20000
470 * fseek() equivalent for AVIOContext.
471 * @return new position or AVERROR.
473 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
476 * Skip given number of bytes forward
477 * @return new position or AVERROR.
479 int64_t avio_skip(AVIOContext *s, int64_t offset);
482 * ftell() equivalent for AVIOContext.
483 * @return position or AVERROR.
485 static av_always_inline int64_t avio_tell(AVIOContext *s)
487 return avio_seek(s, 0, SEEK_CUR);
492 * @return filesize or AVERROR
494 int64_t avio_size(AVIOContext *s);
497 * feof() equivalent for AVIOContext.
498 * @return non zero if and only if end of file
500 int url_feof(AVIOContext *s);
502 /** @warning currently size is limited */
503 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
505 void avio_flush(AVIOContext *s);
509 * Read size bytes from AVIOContext into buf.
510 * @return number of bytes read or AVERROR
512 int avio_read(AVIOContext *s, unsigned char *buf, int size);
515 * @name Functions for reading from AVIOContext
518 * @note return 0 if EOF, so you cannot use it if EOF handling is
521 int avio_r8 (AVIOContext *s);
522 unsigned int avio_rl16(AVIOContext *s);
523 unsigned int avio_rl24(AVIOContext *s);
524 unsigned int avio_rl32(AVIOContext *s);
525 uint64_t avio_rl64(AVIOContext *s);
526 unsigned int avio_rb16(AVIOContext *s);
527 unsigned int avio_rb24(AVIOContext *s);
528 unsigned int avio_rb32(AVIOContext *s);
529 uint64_t avio_rb64(AVIOContext *s);
535 * Read a string from pb into buf. The reading will terminate when either
536 * a NULL character was encountered, maxlen bytes have been read, or nothing
537 * more can be read from pb. The result is guaranteed to be NULL-terminated, it
538 * will be truncated if buf is too small.
539 * Note that the string is not interpreted or validated in any way, it
540 * might get truncated in the middle of a sequence for multi-byte encodings.
542 * @return number of bytes read (is always <= maxlen).
543 * If reading ends on EOF or error, the return value will be one more than
544 * bytes actually read.
546 int avio_get_str(AVIOContext *pb, int maxlen, char *buf, int buflen);
549 * Read a UTF-16 string from pb and convert it to UTF-8.
550 * The reading will terminate when either a null or invalid character was
551 * encountered or maxlen bytes have been read.
552 * @return number of bytes read (is always <= maxlen)
554 int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
555 int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
559 * @name URL open modes
560 * The flags argument to avio_open must be one of the following
561 * constants, optionally ORed with other flags.
564 #define AVIO_FLAG_READ 1 /**< read-only */
565 #define AVIO_FLAG_WRITE 2 /**< write-only */
566 #define AVIO_FLAG_READ_WRITE (AVIO_FLAG_READ|AVIO_FLAG_WRITE) /**< read-write pseudo flag */
572 * Use non-blocking mode.
573 * If this flag is set, operations on the context will return
574 * AVERROR(EAGAIN) if they can not be performed immediately.
575 * If this flag is not set, operations on the context will never return
577 * Note that this flag does not affect the opening/connecting of the
578 * context. Connecting a protocol will always block if necessary (e.g. on
579 * network protocols) but never hang (e.g. on busy devices).
580 * Warning: non-blocking protocols is work-in-progress; this flag may be
583 #define AVIO_FLAG_NONBLOCK 8
586 * Create and initialize a AVIOContext for accessing the
587 * resource indicated by url.
588 * @note When the resource indicated by url has been opened in
589 * read+write mode, the AVIOContext can be used only for writing.
591 * @param s Used to return the pointer to the created AVIOContext.
592 * In case of failure the pointed to value is set to NULL.
593 * @param flags flags which control how the resource indicated by url
595 * @return 0 in case of success, a negative value corresponding to an
596 * AVERROR code in case of failure
598 int avio_open(AVIOContext **s, const char *url, int flags);
601 * Create and initialize a AVIOContext for accessing the
602 * resource indicated by url.
603 * @note When the resource indicated by url has been opened in
604 * read+write mode, the AVIOContext can be used only for writing.
606 * @param s Used to return the pointer to the created AVIOContext.
607 * In case of failure the pointed to value is set to NULL.
608 * @param flags flags which control how the resource indicated by url
610 * @param int_cb an interrupt callback to be used at the protocols level
611 * @param options A dictionary filled with protocol-private options. On return
612 * this parameter will be destroyed and replaced with a dict containing options
613 * that were not found. May be NULL.
614 * @return 0 in case of success, a negative value corresponding to an
615 * AVERROR code in case of failure
617 int avio_open2(AVIOContext **s, const char *url, int flags,
618 const AVIOInterruptCB *int_cb, AVDictionary **options);
621 * Close the resource accessed by the AVIOContext s and free it.
622 * This function can only be used if s was opened by avio_open().
624 * @return 0 on success, an AVERROR < 0 on error.
626 int avio_close(AVIOContext *s);
629 * Open a write only memory stream.
631 * @param s new IO context
632 * @return zero if no error.
634 int avio_open_dyn_buf(AVIOContext **s);
637 * Return the written size and a pointer to the buffer. The buffer
638 * must be freed with av_free().
639 * Padding of FF_INPUT_BUFFER_PADDING_SIZE is added to the buffer.
641 * @param s IO context
642 * @param pbuffer pointer to a byte buffer
643 * @return the length of the byte buffer
645 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
648 * Iterate through names of available protocols.
649 * @note it is recommanded to use av_protocol_next() instead of this
651 * @param opaque A private pointer representing current protocol.
652 * It must be a pointer to NULL on first iteration and will
653 * be updated by successive calls to avio_enum_protocols.
654 * @param output If set to 1, iterate over output protocols,
655 * otherwise over input protocols.
657 * @return A static string containing the name of current protocol or NULL
659 const char *avio_enum_protocols(void **opaque, int output);
662 * Pause and resume playing - only meaningful if using a network streaming
663 * protocol (e.g. MMS).
664 * @param pause 1 for pause, 0 for resume
666 int avio_pause(AVIOContext *h, int pause);
669 * Seek to a given timestamp relative to some component stream.
670 * Only meaningful if using a network streaming protocol (e.g. MMS.).
671 * @param stream_index The stream index that the timestamp is relative to.
672 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
673 * units from the beginning of the presentation.
674 * If a stream_index >= 0 is used and the protocol does not support
675 * seeking based on component streams, the call will fail with ENOTSUP.
676 * @param timestamp timestamp in AVStream.time_base units
677 * or if there is no stream specified then in AV_TIME_BASE units.
678 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
679 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
680 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
681 * fail with ENOTSUP if used and not supported.
682 * @return >= 0 on success
683 * @see AVInputFormat::read_seek
685 int64_t avio_seek_time(AVIOContext *h, int stream_index,
686 int64_t timestamp, int flags);
688 #endif /* AVFORMAT_AVIO_H */