lavf: use the io_open callbacks for files opened from open_input() as well
[libav.git] / libavformat / avformat.h
1 /*
2 * copyright (c) 2001 Fabrice Bellard
3 *
4 * This file is part of Libav.
5 *
6 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #ifndef AVFORMAT_AVFORMAT_H
22 #define AVFORMAT_AVFORMAT_H
23
24 /**
25 * @file
26 * @ingroup libavf
27 * Main libavformat public API header
28 */
29
30 /**
31 * @defgroup libavf I/O and Muxing/Demuxing Library
32 * @{
33 *
34 * Libavformat (lavf) is a library for dealing with various media container
35 * formats. Its main two purposes are demuxing - i.e. splitting a media file
36 * into component streams, and the reverse process of muxing - writing supplied
37 * data in a specified container format. It also has an @ref lavf_io
38 * "I/O module" which supports a number of protocols for accessing the data (e.g.
39 * file, tcp, http and others). Before using lavf, you need to call
40 * av_register_all() to register all compiled muxers, demuxers and protocols.
41 * Unless you are absolutely sure you won't use libavformat's network
42 * capabilities, you should also call avformat_network_init().
43 *
44 * A supported input format is described by an AVInputFormat struct, conversely
45 * an output format is described by AVOutputFormat. You can iterate over all
46 * registered input/output formats using the av_iformat_next() /
47 * av_oformat_next() functions. The protocols layer is not part of the public
48 * API, so you can only get the names of supported protocols with the
49 * avio_enum_protocols() function.
50 *
51 * Main lavf structure used for both muxing and demuxing is AVFormatContext,
52 * which exports all information about the file being read or written. As with
53 * most Libav structures, its size is not part of public ABI, so it cannot be
54 * allocated on stack or directly with av_malloc(). To create an
55 * AVFormatContext, use avformat_alloc_context() (some functions, like
56 * avformat_open_input() might do that for you).
57 *
58 * Most importantly an AVFormatContext contains:
59 * @li the @ref AVFormatContext.iformat "input" or @ref AVFormatContext.oformat
60 * "output" format. It is either autodetected or set by user for input;
61 * always set by user for output.
62 * @li an @ref AVFormatContext.streams "array" of AVStreams, which describe all
63 * elementary streams stored in the file. AVStreams are typically referred to
64 * using their index in this array.
65 * @li an @ref AVFormatContext.pb "I/O context". It is either opened by lavf or
66 * set by user for input, always set by user for output (unless you are dealing
67 * with an AVFMT_NOFILE format).
68 *
69 * @section lavf_options Passing options to (de)muxers
70 * Lavf allows to configure muxers and demuxers using the @ref avoptions
71 * mechanism. Generic (format-independent) libavformat options are provided by
72 * AVFormatContext, they can be examined from a user program by calling
73 * av_opt_next() / av_opt_find() on an allocated AVFormatContext (or its AVClass
74 * from avformat_get_class()). Private (format-specific) options are provided by
75 * AVFormatContext.priv_data if and only if AVInputFormat.priv_class /
76 * AVOutputFormat.priv_class of the corresponding format struct is non-NULL.
77 * Further options may be provided by the @ref AVFormatContext.pb "I/O context",
78 * if its AVClass is non-NULL, and the protocols layer. See the discussion on
79 * nesting in @ref avoptions documentation to learn how to access those.
80 *
81 * @defgroup lavf_decoding Demuxing
82 * @{
83 * Demuxers read a media file and split it into chunks of data (@em packets). A
84 * @ref AVPacket "packet" contains one or more encoded frames which belongs to a
85 * single elementary stream. In the lavf API this process is represented by the
86 * avformat_open_input() function for opening a file, av_read_frame() for
87 * reading a single packet and finally avformat_close_input(), which does the
88 * cleanup.
89 *
90 * @section lavf_decoding_open Opening a media file
91 * The minimum information required to open a file is its URL or filename, which
92 * is passed to avformat_open_input(), as in the following code:
93 * @code
94 * const char *url = "in.mp3";
95 * AVFormatContext *s = NULL;
96 * int ret = avformat_open_input(&s, url, NULL, NULL);
97 * if (ret < 0)
98 * abort();
99 * @endcode
100 * The above code attempts to allocate an AVFormatContext, open the
101 * specified file (autodetecting the format) and read the header, exporting the
102 * information stored there into s. Some formats do not have a header or do not
103 * store enough information there, so it is recommended that you call the
104 * avformat_find_stream_info() function which tries to read and decode a few
105 * frames to find missing information.
106 *
107 * In some cases you might want to preallocate an AVFormatContext yourself with
108 * avformat_alloc_context() and do some tweaking on it before passing it to
109 * avformat_open_input(). One such case is when you want to use custom functions
110 * for reading input data instead of lavf internal I/O layer.
111 * To do that, create your own AVIOContext with avio_alloc_context(), passing
112 * your reading callbacks to it. Then set the @em pb field of your
113 * AVFormatContext to newly created AVIOContext.
114 *
115 * Since the format of the opened file is in general not known until after
116 * avformat_open_input() has returned, it is not possible to set demuxer private
117 * options on a preallocated context. Instead, the options should be passed to
118 * avformat_open_input() wrapped in an AVDictionary:
119 * @code
120 * AVDictionary *options = NULL;
121 * av_dict_set(&options, "video_size", "640x480", 0);
122 * av_dict_set(&options, "pixel_format", "rgb24", 0);
123 *
124 * if (avformat_open_input(&s, url, NULL, &options) < 0)
125 * abort();
126 * av_dict_free(&options);
127 * @endcode
128 * This code passes the private options 'video_size' and 'pixel_format' to the
129 * demuxer. They would be necessary for e.g. the rawvideo demuxer, since it
130 * cannot know how to interpret raw video data otherwise. If the format turns
131 * out to be something different than raw video, those options will not be
132 * recognized by the demuxer and therefore will not be applied. Such unrecognized
133 * options are then returned in the options dictionary (recognized options are
134 * consumed). The calling program can handle such unrecognized options as it
135 * wishes, e.g.
136 * @code
137 * AVDictionaryEntry *e;
138 * if (e = av_dict_get(options, "", NULL, AV_DICT_IGNORE_SUFFIX)) {
139 * fprintf(stderr, "Option %s not recognized by the demuxer.\n", e->key);
140 * abort();
141 * }
142 * @endcode
143 *
144 * After you have finished reading the file, you must close it with
145 * avformat_close_input(). It will free everything associated with the file.
146 *
147 * @section lavf_decoding_read Reading from an opened file
148 * Reading data from an opened AVFormatContext is done by repeatedly calling
149 * av_read_frame() on it. Each call, if successful, will return an AVPacket
150 * containing encoded data for one AVStream, identified by
151 * AVPacket.stream_index. This packet may be passed straight into the libavcodec
152 * decoding functions avcodec_decode_video2(), avcodec_decode_audio4() or
153 * avcodec_decode_subtitle2() if the caller wishes to decode the data.
154 *
155 * AVPacket.pts, AVPacket.dts and AVPacket.duration timing information will be
156 * set if known. They may also be unset (i.e. AV_NOPTS_VALUE for
157 * pts/dts, 0 for duration) if the stream does not provide them. The timing
158 * information will be in AVStream.time_base units, i.e. it has to be
159 * multiplied by the timebase to convert them to seconds.
160 *
161 * If AVPacket.buf is set on the returned packet, then the packet is
162 * allocated dynamically and the user may keep it indefinitely.
163 * Otherwise, if AVPacket.buf is NULL, the packet data is backed by a
164 * static storage somewhere inside the demuxer and the packet is only valid
165 * until the next av_read_frame() call or closing the file. If the caller
166 * requires a longer lifetime, av_dup_packet() will make an av_malloc()ed copy
167 * of it.
168 * In both cases, the packet must be freed with av_packet_unref() when it is no
169 * longer needed.
170 *
171 * @section lavf_decoding_seek Seeking
172 * @}
173 *
174 * @defgroup lavf_encoding Muxing
175 * @{
176 * Muxers take encoded data in the form of @ref AVPacket "AVPackets" and write
177 * it into files or other output bytestreams in the specified container format.
178 *
179 * The main API functions for muxing are avformat_write_header() for writing the
180 * file header, av_write_frame() / av_interleaved_write_frame() for writing the
181 * packets and av_write_trailer() for finalizing the file.
182 *
183 * At the beginning of the muxing process, the caller must first call
184 * avformat_alloc_context() to create a muxing context. The caller then sets up
185 * the muxer by filling the various fields in this context:
186 *
187 * - The @ref AVFormatContext.oformat "oformat" field must be set to select the
188 * muxer that will be used.
189 * - Unless the format is of the AVFMT_NOFILE type, the @ref AVFormatContext.pb
190 * "pb" field must be set to an opened IO context, either returned from
191 * avio_open2() or a custom one.
192 * - Unless the format is of the AVFMT_NOSTREAMS type, at least one stream must
193 * be created with the avformat_new_stream() function. The caller should fill
194 * the @ref AVStream.codec "stream codec context" information, such as the
195 * codec @ref AVCodecContext.codec_type "type", @ref AVCodecContext.codec_id
196 * "id" and other parameters (e.g. width / height, the pixel or sample format,
197 * etc.) as known. The @ref AVStream.time_base "stream timebase" should
198 * be set to the timebase that the caller desires to use for this stream (note
199 * that the timebase actually used by the muxer can be different, as will be
200 * described later).
201 * - It is advised to manually initialize only the relevant fields in
202 * AVCodecContext, rather than using @ref avcodec_copy_context() during
203 * remuxing: there is no guarantee that the codec context values remain valid
204 * for both input and output format contexts.
205 * - The caller may fill in additional information, such as @ref
206 * AVFormatContext.metadata "global" or @ref AVStream.metadata "per-stream"
207 * metadata, @ref AVFormatContext.chapters "chapters", @ref
208 * AVFormatContext.programs "programs", etc. as described in the
209 * AVFormatContext documentation. Whether such information will actually be
210 * stored in the output depends on what the container format and the muxer
211 * support.
212 *
213 * When the muxing context is fully set up, the caller must call
214 * avformat_write_header() to initialize the muxer internals and write the file
215 * header. Whether anything actually is written to the IO context at this step
216 * depends on the muxer, but this function must always be called. Any muxer
217 * private options must be passed in the options parameter to this function.
218 *
219 * The data is then sent to the muxer by repeatedly calling av_write_frame() or
220 * av_interleaved_write_frame() (consult those functions' documentation for
221 * discussion on the difference between them; only one of them may be used with
222 * a single muxing context, they should not be mixed). Do note that the timing
223 * information on the packets sent to the muxer must be in the corresponding
224 * AVStream's timebase. That timebase is set by the muxer (in the
225 * avformat_write_header() step) and may be different from the timebase
226 * requested by the caller.
227 *
228 * Once all the data has been written, the caller must call av_write_trailer()
229 * to flush any buffered packets and finalize the output file, then close the IO
230 * context (if any) and finally free the muxing context with
231 * avformat_free_context().
232 * @}
233 *
234 * @defgroup lavf_io I/O Read/Write
235 * @{
236 * @}
237 *
238 * @defgroup lavf_codec Demuxers
239 * @{
240 * @defgroup lavf_codec_native Native Demuxers
241 * @{
242 * @}
243 * @defgroup lavf_codec_wrappers External library wrappers
244 * @{
245 * @}
246 * @}
247 * @defgroup lavf_protos I/O Protocols
248 * @{
249 * @}
250 * @defgroup lavf_internal Internal
251 * @{
252 * @}
253 * @}
254 */
255
256 #include <time.h>
257 #include <stdio.h> /* FILE */
258 #include "libavcodec/avcodec.h"
259 #include "libavutil/dict.h"
260 #include "libavutil/log.h"
261
262 #include "avio.h"
263 #include "libavformat/version.h"
264
265 struct AVFormatContext;
266
267
268 /**
269 * @defgroup metadata_api Public Metadata API
270 * @{
271 * @ingroup libavf
272 * The metadata API allows libavformat to export metadata tags to a client
273 * application when demuxing. Conversely it allows a client application to
274 * set metadata when muxing.
275 *
276 * Metadata is exported or set as pairs of key/value strings in the 'metadata'
277 * fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
278 * using the @ref lavu_dict "AVDictionary" API. Like all strings in Libav,
279 * metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
280 * exported by demuxers isn't checked to be valid UTF-8 in most cases.
281 *
282 * Important concepts to keep in mind:
283 * - Keys are unique; there can never be 2 tags with the same key. This is
284 * also meant semantically, i.e., a demuxer should not knowingly produce
285 * several keys that are literally different but semantically identical.
286 * E.g., key=Author5, key=Author6. In this example, all authors must be
287 * placed in the same tag.
288 * - Metadata is flat, not hierarchical; there are no subtags. If you
289 * want to store, e.g., the email address of the child of producer Alice
290 * and actor Bob, that could have key=alice_and_bobs_childs_email_address.
291 * - Several modifiers can be applied to the tag name. This is done by
292 * appending a dash character ('-') and the modifier name in the order
293 * they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
294 * - language -- a tag whose value is localized for a particular language
295 * is appended with the ISO 639-2/B 3-letter language code.
296 * For example: Author-ger=Michael, Author-eng=Mike
297 * The original/default language is in the unqualified "Author" tag.
298 * A demuxer should set a default if it sets any translated tag.
299 * - sorting -- a modified version of a tag that should be used for
300 * sorting will have '-sort' appended. E.g. artist="The Beatles",
301 * artist-sort="Beatles, The".
302 * - Some protocols and demuxers support metadata updates. After a successful
303 * call to av_read_packet(), AVFormatContext.event_flags or AVStream.event_flags
304 * will be updated to indicate if metadata changed. In order to detect metadata
305 * changes on a stream, you need to loop through all streams in the AVFormatContext
306 * and check their individual event_flags.
307 *
308 * - Demuxers attempt to export metadata in a generic format, however tags
309 * with no generic equivalents are left as they are stored in the container.
310 * Follows a list of generic tag names:
311 *
312 @verbatim
313 album -- name of the set this work belongs to
314 album_artist -- main creator of the set/album, if different from artist.
315 e.g. "Various Artists" for compilation albums.
316 artist -- main creator of the work
317 comment -- any additional description of the file.
318 composer -- who composed the work, if different from artist.
319 copyright -- name of copyright holder.
320 creation_time-- date when the file was created, preferably in ISO 8601.
321 date -- date when the work was created, preferably in ISO 8601.
322 disc -- number of a subset, e.g. disc in a multi-disc collection.
323 encoder -- name/settings of the software/hardware that produced the file.
324 encoded_by -- person/group who created the file.
325 filename -- original name of the file.
326 genre -- <self-evident>.
327 language -- main language in which the work is performed, preferably
328 in ISO 639-2 format. Multiple languages can be specified by
329 separating them with commas.
330 performer -- artist who performed the work, if different from artist.
331 E.g for "Also sprach Zarathustra", artist would be "Richard
332 Strauss" and performer "London Philharmonic Orchestra".
333 publisher -- name of the label/publisher.
334 service_name -- name of the service in broadcasting (channel name).
335 service_provider -- name of the service provider in broadcasting.
336 title -- name of the work.
337 track -- number of this work in the set, can be in form current/total.
338 variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
339 @endverbatim
340 *
341 * Look in the examples section for an application example how to use the Metadata API.
342 *
343 * @}
344 */
345
346 /* packet functions */
347
348
349 /**
350 * Allocate and read the payload of a packet and initialize its
351 * fields with default values.
352 *
353 * @param s associated IO context
354 * @param pkt packet
355 * @param size desired payload size
356 * @return >0 (read size) if OK, AVERROR_xxx otherwise
357 */
358 int av_get_packet(AVIOContext *s, AVPacket *pkt, int size);
359
360
361 /**
362 * Read data and append it to the current content of the AVPacket.
363 * If pkt->size is 0 this is identical to av_get_packet.
364 * Note that this uses av_grow_packet and thus involves a realloc
365 * which is inefficient. Thus this function should only be used
366 * when there is no reasonable way to know (an upper bound of)
367 * the final size.
368 *
369 * @param s associated IO context
370 * @param pkt packet
371 * @param size amount of data to read
372 * @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
373 * will not be lost even if an error occurs.
374 */
375 int av_append_packet(AVIOContext *s, AVPacket *pkt, int size);
376
377 #if FF_API_LAVF_FRAC
378 /*************************************************/
379 /* fractional numbers for exact pts handling */
380
381 /**
382 * The exact value of the fractional number is: 'val + num / den'.
383 * num is assumed to be 0 <= num < den.
384 */
385 typedef struct AVFrac {
386 int64_t val, num, den;
387 } AVFrac;
388 #endif
389
390 /*************************************************/
391 /* input/output formats */
392
393 struct AVCodecTag;
394
395 /**
396 * This structure contains the data a format has to probe a file.
397 */
398 typedef struct AVProbeData {
399 const char *filename;
400 unsigned char *buf; /**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */
401 int buf_size; /**< Size of buf except extra allocated bytes */
402 const char *mime_type; /**< mime_type, when known. */
403 } AVProbeData;
404
405 #define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
406 #define AVPROBE_SCORE_MIME 75 ///< score for file mime type
407 #define AVPROBE_SCORE_MAX 100 ///< maximum score
408
409 #define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
410
411 /// Demuxer will use avio_open, no opened file should be provided by the caller.
412 #define AVFMT_NOFILE 0x0001
413 #define AVFMT_NEEDNUMBER 0x0002 /**< Needs '%d' in filename. */
414 #define AVFMT_SHOW_IDS 0x0008 /**< Show format stream IDs numbers. */
415 #if FF_API_LAVF_FMT_RAWPICTURE
416 #define AVFMT_RAWPICTURE 0x0020 /**< Format wants AVPicture structure for
417 raw picture data. @deprecated Not used anymore */
418 #endif
419 #define AVFMT_GLOBALHEADER 0x0040 /**< Format wants global header. */
420 #define AVFMT_NOTIMESTAMPS 0x0080 /**< Format does not need / have any timestamps. */
421 #define AVFMT_GENERIC_INDEX 0x0100 /**< Use generic index building code. */
422 #define AVFMT_TS_DISCONT 0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
423 #define AVFMT_VARIABLE_FPS 0x0400 /**< Format allows variable fps. */
424 #define AVFMT_NODIMENSIONS 0x0800 /**< Format does not need width/height */
425 #define AVFMT_NOSTREAMS 0x1000 /**< Format does not require any streams */
426 #define AVFMT_NOBINSEARCH 0x2000 /**< Format does not allow to fall back on binary search via read_timestamp */
427 #define AVFMT_NOGENSEARCH 0x4000 /**< Format does not allow to fall back on generic search */
428 #define AVFMT_NO_BYTE_SEEK 0x8000 /**< Format does not allow seeking by bytes */
429 #define AVFMT_ALLOW_FLUSH 0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
430 #define AVFMT_TS_NONSTRICT 0x20000 /**< Format does not require strictly
431 increasing timestamps, but they must
432 still be monotonic */
433 #define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative
434 timestamps. If not set the timestamp
435 will be shifted in av_write_frame and
436 av_interleaved_write_frame so they
437 start from 0. */
438
439 /**
440 * @addtogroup lavf_encoding
441 * @{
442 */
443 typedef struct AVOutputFormat {
444 const char *name;
445 /**
446 * Descriptive name for the format, meant to be more human-readable
447 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
448 * to define it.
449 */
450 const char *long_name;
451 const char *mime_type;
452 const char *extensions; /**< comma-separated filename extensions */
453 /* output support */
454 enum AVCodecID audio_codec; /**< default audio codec */
455 enum AVCodecID video_codec; /**< default video codec */
456 enum AVCodecID subtitle_codec; /**< default subtitle codec */
457 /**
458 * can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER,
459 * AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
460 * AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
461 * AVFMT_TS_NONSTRICT
462 */
463 int flags;
464
465 /**
466 * List of supported codec_id-codec_tag pairs, ordered by "better
467 * choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
468 */
469 const struct AVCodecTag * const *codec_tag;
470
471
472 const AVClass *priv_class; ///< AVClass for the private context
473
474 /*****************************************************************
475 * No fields below this line are part of the public API. They
476 * may not be used outside of libavformat and can be changed and
477 * removed at will.
478 * New public fields should be added right above.
479 *****************************************************************
480 */
481 struct AVOutputFormat *next;
482 /**
483 * size of private data so that it can be allocated in the wrapper
484 */
485 int priv_data_size;
486
487 int (*write_header)(struct AVFormatContext *);
488 /**
489 * Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,
490 * pkt can be NULL in order to flush data buffered in the muxer.
491 * When flushing, return 0 if there still is more data to flush,
492 * or 1 if everything was flushed and there is no more buffered
493 * data.
494 */
495 int (*write_packet)(struct AVFormatContext *, AVPacket *pkt);
496 int (*write_trailer)(struct AVFormatContext *);
497 /**
498 * Currently only used to set pixel format if not YUV420P.
499 */
500 int (*interleave_packet)(struct AVFormatContext *, AVPacket *out,
501 AVPacket *in, int flush);
502 /**
503 * Test if the given codec can be stored in this container.
504 *
505 * @return 1 if the codec is supported, 0 if it is not.
506 * A negative number if unknown.
507 */
508 int (*query_codec)(enum AVCodecID id, int std_compliance);
509 } AVOutputFormat;
510 /**
511 * @}
512 */
513
514 /**
515 * @addtogroup lavf_decoding
516 * @{
517 */
518 typedef struct AVInputFormat {
519 /**
520 * A comma separated list of short names for the format. New names
521 * may be appended with a minor bump.
522 */
523 const char *name;
524
525 /**
526 * Descriptive name for the format, meant to be more human-readable
527 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
528 * to define it.
529 */
530 const char *long_name;
531
532 /**
533 * Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
534 * AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
535 * AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK.
536 */
537 int flags;
538
539 /**
540 * If extensions are defined, then no probe is done. You should
541 * usually not use extension format guessing because it is not
542 * reliable enough
543 */
544 const char *extensions;
545
546 const struct AVCodecTag * const *codec_tag;
547
548 const AVClass *priv_class; ///< AVClass for the private context
549
550 /**
551 * Comma-separated list of mime types.
552 * It is used check for matching mime types while probing.
553 * @see av_probe_input_format2
554 */
555 const char *mime_type;
556
557 /*****************************************************************
558 * No fields below this line are part of the public API. They
559 * may not be used outside of libavformat and can be changed and
560 * removed at will.
561 * New public fields should be added right above.
562 *****************************************************************
563 */
564 struct AVInputFormat *next;
565
566 /**
567 * Raw demuxers store their codec ID here.
568 */
569 int raw_codec_id;
570
571 /**
572 * Size of private data so that it can be allocated in the wrapper.
573 */
574 int priv_data_size;
575
576 /**
577 * Tell if a given file has a chance of being parsed as this format.
578 * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
579 * big so you do not have to check for that unless you need more.
580 */
581 int (*read_probe)(AVProbeData *);
582
583 /**
584 * Read the format header and initialize the AVFormatContext
585 * structure. Return 0 if OK. 'avformat_new_stream' should be
586 * called to create new streams.
587 */
588 int (*read_header)(struct AVFormatContext *);
589
590 /**
591 * Read one packet and put it in 'pkt'. pts and flags are also
592 * set. 'avformat_new_stream' can be called only if the flag
593 * AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
594 * background thread).
595 * @return 0 on success, < 0 on error.
596 * When returning an error, pkt must not have been allocated
597 * or must be freed before returning
598 */
599 int (*read_packet)(struct AVFormatContext *, AVPacket *pkt);
600
601 /**
602 * Close the stream. The AVFormatContext and AVStreams are not
603 * freed by this function
604 */
605 int (*read_close)(struct AVFormatContext *);
606
607 /**
608 * Seek to a given timestamp relative to the frames in
609 * stream component stream_index.
610 * @param stream_index Must not be -1.
611 * @param flags Selects which direction should be preferred if no exact
612 * match is available.
613 * @return >= 0 on success (but not necessarily the new offset)
614 */
615 int (*read_seek)(struct AVFormatContext *,
616 int stream_index, int64_t timestamp, int flags);
617
618 /**
619 * Get the next timestamp in stream[stream_index].time_base units.
620 * @return the timestamp or AV_NOPTS_VALUE if an error occurred
621 */
622 int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index,
623 int64_t *pos, int64_t pos_limit);
624
625 /**
626 * Start/resume playing - only meaningful if using a network-based format
627 * (RTSP).
628 */
629 int (*read_play)(struct AVFormatContext *);
630
631 /**
632 * Pause playing - only meaningful if using a network-based format
633 * (RTSP).
634 */
635 int (*read_pause)(struct AVFormatContext *);
636
637 /**
638 * Seek to timestamp ts.
639 * Seeking will be done so that the point from which all active streams
640 * can be presented successfully will be closest to ts and within min/max_ts.
641 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
642 */
643 int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
644 } AVInputFormat;
645 /**
646 * @}
647 */
648
649 enum AVStreamParseType {
650 AVSTREAM_PARSE_NONE,
651 AVSTREAM_PARSE_FULL, /**< full parsing and repack */
652 AVSTREAM_PARSE_HEADERS, /**< Only parse headers, do not repack. */
653 AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */
654 AVSTREAM_PARSE_FULL_ONCE, /**< full parsing and repack of the first frame only, only implemented for H.264 currently */
655 };
656
657 typedef struct AVIndexEntry {
658 int64_t pos;
659 int64_t timestamp;
660 #define AVINDEX_KEYFRAME 0x0001
661 int flags:2;
662 int size:30; //Yeah, trying to keep the size of this small to reduce memory requirements (it is 24 vs. 32 bytes due to possible 8-byte alignment).
663 int min_distance; /**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */
664 } AVIndexEntry;
665
666 #define AV_DISPOSITION_DEFAULT 0x0001
667 #define AV_DISPOSITION_DUB 0x0002
668 #define AV_DISPOSITION_ORIGINAL 0x0004
669 #define AV_DISPOSITION_COMMENT 0x0008
670 #define AV_DISPOSITION_LYRICS 0x0010
671 #define AV_DISPOSITION_KARAOKE 0x0020
672
673 /**
674 * Track should be used during playback by default.
675 * Useful for subtitle track that should be displayed
676 * even when user did not explicitly ask for subtitles.
677 */
678 #define AV_DISPOSITION_FORCED 0x0040
679 #define AV_DISPOSITION_HEARING_IMPAIRED 0x0080 /**< stream for hearing impaired audiences */
680 #define AV_DISPOSITION_VISUAL_IMPAIRED 0x0100 /**< stream for visual impaired audiences */
681 #define AV_DISPOSITION_CLEAN_EFFECTS 0x0200 /**< stream without voice */
682 /**
683 * The stream is stored in the file as an attached picture/"cover art" (e.g.
684 * APIC frame in ID3v2). The single packet associated with it will be returned
685 * among the first few packets read from the file unless seeking takes place.
686 * It can also be accessed at any time in AVStream.attached_pic.
687 */
688 #define AV_DISPOSITION_ATTACHED_PIC 0x0400
689
690 typedef struct AVStreamInternal AVStreamInternal;
691
692 /**
693 * Stream structure.
694 * New fields can be added to the end with minor version bumps.
695 * Removal, reordering and changes to existing fields require a major
696 * version bump.
697 * sizeof(AVStream) must not be used outside libav*.
698 */
699 typedef struct AVStream {
700 int index; /**< stream index in AVFormatContext */
701 /**
702 * Format-specific stream ID.
703 * decoding: set by libavformat
704 * encoding: set by the user, replaced by libavformat if left unset
705 */
706 int id;
707 /**
708 * Codec context associated with this stream. Allocated and freed by
709 * libavformat.
710 *
711 * - decoding: The demuxer exports codec information stored in the headers
712 * here.
713 * - encoding: The user sets codec information, the muxer writes it to the
714 * output. Mandatory fields as specified in AVCodecContext
715 * documentation must be set even if this AVCodecContext is
716 * not actually used for encoding.
717 */
718 AVCodecContext *codec;
719 void *priv_data;
720
721 #if FF_API_LAVF_FRAC
722 /**
723 * @deprecated this field is unused
724 */
725 attribute_deprecated
726 struct AVFrac pts;
727 #endif
728
729 /**
730 * This is the fundamental unit of time (in seconds) in terms
731 * of which frame timestamps are represented.
732 *
733 * decoding: set by libavformat
734 * encoding: May be set by the caller before avformat_write_header() to
735 * provide a hint to the muxer about the desired timebase. In
736 * avformat_write_header(), the muxer will overwrite this field
737 * with the timebase that will actually be used for the timestamps
738 * written into the file (which may or may not be related to the
739 * user-provided one, depending on the format).
740 */
741 AVRational time_base;
742
743 /**
744 * Decoding: pts of the first frame of the stream, in stream time base.
745 * Only set this if you are absolutely 100% sure that the value you set
746 * it to really is the pts of the first frame.
747 * This may be undefined (AV_NOPTS_VALUE).
748 */
749 int64_t start_time;
750
751 /**
752 * Decoding: duration of the stream, in stream time base.
753 * If a source file does not specify a duration, but does specify
754 * a bitrate, this value will be estimated from bitrate and file size.
755 */
756 int64_t duration;
757
758 int64_t nb_frames; ///< number of frames in this stream if known or 0
759
760 int disposition; /**< AV_DISPOSITION_* bit field */
761
762 enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
763
764 /**
765 * sample aspect ratio (0 if unknown)
766 * - encoding: Set by user.
767 * - decoding: Set by libavformat.
768 */
769 AVRational sample_aspect_ratio;
770
771 AVDictionary *metadata;
772
773 /**
774 * Average framerate
775 *
776 * - demuxing: May be set by libavformat when creating the stream or in
777 * avformat_find_stream_info().
778 * - muxing: May be set by the caller before avformat_write_header().
779 */
780 AVRational avg_frame_rate;
781
782 /**
783 * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
784 * will contain the attached picture.
785 *
786 * decoding: set by libavformat, must not be modified by the caller.
787 * encoding: unused
788 */
789 AVPacket attached_pic;
790
791 /**
792 * An array of side data that applies to the whole stream (i.e. the
793 * container does not allow it to change between packets).
794 *
795 * There may be no overlap between the side data in this array and side data
796 * in the packets. I.e. a given side data is either exported by the muxer
797 * (demuxing) / set by the caller (muxing) in this array, then it never
798 * appears in the packets, or the side data is exported / sent through
799 * the packets (always in the first packet where the value becomes known or
800 * changes), then it does not appear in this array.
801 *
802 * - demuxing: Set by libavformat when the stream is created.
803 * - muxing: May be set by the caller before avformat_write_header().
804 *
805 * Freed by libavformat in avformat_free_context().
806 */
807 AVPacketSideData *side_data;
808 /**
809 * The number of elements in the AVStream.side_data array.
810 */
811 int nb_side_data;
812
813 /**
814 * Flags for the user to detect events happening on the stream. Flags must
815 * be cleared by the user once the event has been handled.
816 * A combination of AVSTREAM_EVENT_FLAG_*.
817 */
818 int event_flags;
819 #define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
820
821 /*****************************************************************
822 * All fields below this line are not part of the public API. They
823 * may not be used outside of libavformat and can be changed and
824 * removed at will.
825 * New public fields should be added right above.
826 *****************************************************************
827 */
828
829 /**
830 * Stream information used internally by av_find_stream_info()
831 */
832 #define MAX_STD_TIMEBASES (60*12+5)
833 struct {
834 int nb_decoded_frames;
835 int found_decoder;
836
837 /**
838 * Those are used for average framerate estimation.
839 */
840 int64_t fps_first_dts;
841 int fps_first_dts_idx;
842 int64_t fps_last_dts;
843 int fps_last_dts_idx;
844
845 } *info;
846
847 int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
848
849 // Timestamp generation support:
850 int64_t first_dts;
851 int64_t cur_dts;
852 int64_t last_IP_pts;
853 int last_IP_duration;
854
855 /**
856 * Number of packets to buffer for codec probing
857 */
858 #define MAX_PROBE_PACKETS 2500
859 int probe_packets;
860
861 /**
862 * Number of frames that have been demuxed during av_find_stream_info()
863 */
864 int codec_info_nb_frames;
865
866 /* av_read_frame() support */
867 enum AVStreamParseType need_parsing;
868 struct AVCodecParserContext *parser;
869
870 /**
871 * last packet in packet_buffer for this stream when muxing.
872 */
873 struct AVPacketList *last_in_packet_buffer;
874 AVProbeData probe_data;
875 #define MAX_REORDER_DELAY 16
876 int64_t pts_buffer[MAX_REORDER_DELAY+1];
877
878 AVIndexEntry *index_entries; /**< Only used if the format does not
879 support seeking natively. */
880 int nb_index_entries;
881 unsigned int index_entries_allocated_size;
882
883 /**
884 * An opaque field for libavformat internal usage.
885 * Must not be accessed in any way by callers.
886 */
887 AVStreamInternal *internal;
888 } AVStream;
889
890 #define AV_PROGRAM_RUNNING 1
891
892 /**
893 * New fields can be added to the end with minor version bumps.
894 * Removal, reordering and changes to existing fields require a major
895 * version bump.
896 * sizeof(AVProgram) must not be used outside libav*.
897 */
898 typedef struct AVProgram {
899 int id;
900 int flags;
901 enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
902 unsigned int *stream_index;
903 unsigned int nb_stream_indexes;
904 AVDictionary *metadata;
905 } AVProgram;
906
907 #define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
908 (streams are added dynamically) */
909
910 typedef struct AVChapter {
911 int id; ///< unique ID to identify the chapter
912 AVRational time_base; ///< time base in which the start/end timestamps are specified
913 int64_t start, end; ///< chapter start/end time in time_base units
914 AVDictionary *metadata;
915 } AVChapter;
916
917 typedef struct AVFormatInternal AVFormatInternal;
918
919 /**
920 * Format I/O context.
921 * New fields can be added to the end with minor version bumps.
922 * Removal, reordering and changes to existing fields require a major
923 * version bump.
924 * sizeof(AVFormatContext) must not be used outside libav*, use
925 * avformat_alloc_context() to create an AVFormatContext.
926 */
927 typedef struct AVFormatContext {
928 /**
929 * A class for logging and @ref avoptions. Set by avformat_alloc_context().
930 * Exports (de)muxer private options if they exist.
931 */
932 const AVClass *av_class;
933
934 /**
935 * The input container format.
936 *
937 * Demuxing only, set by avformat_open_input().
938 */
939 struct AVInputFormat *iformat;
940
941 /**
942 * The output container format.
943 *
944 * Muxing only, must be set by the caller before avformat_write_header().
945 */
946 struct AVOutputFormat *oformat;
947
948 /**
949 * Format private data. This is an AVOptions-enabled struct
950 * if and only if iformat/oformat.priv_class is not NULL.
951 *
952 * - muxing: set by avformat_write_header()
953 * - demuxing: set by avformat_open_input()
954 */
955 void *priv_data;
956
957 /**
958 * I/O context.
959 *
960 * - demuxing: either set by the user before avformat_open_input() (then
961 * the user must close it manually) or set by avformat_open_input().
962 * - muxing: set by the user before avformat_write_header(). The caller must
963 * take care of closing / freeing the IO context.
964 *
965 * Do NOT set this field if AVFMT_NOFILE flag is set in
966 * iformat/oformat.flags. In such a case, the (de)muxer will handle
967 * I/O in some other way and this field will be NULL.
968 */
969 AVIOContext *pb;
970
971 /* stream info */
972 /**
973 * Flags signalling stream properties. A combination of AVFMTCTX_*.
974 * Set by libavformat.
975 */
976 int ctx_flags;
977
978 /**
979 * Number of elements in AVFormatContext.streams.
980 *
981 * Set by avformat_new_stream(), must not be modified by any other code.
982 */
983 unsigned int nb_streams;
984 /**
985 * A list of all streams in the file. New streams are created with
986 * avformat_new_stream().
987 *
988 * - demuxing: streams are created by libavformat in avformat_open_input().
989 * If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
990 * appear in av_read_frame().
991 * - muxing: streams are created by the user before avformat_write_header().
992 *
993 * Freed by libavformat in avformat_free_context().
994 */
995 AVStream **streams;
996
997 /**
998 * input or output filename
999 *
1000 * - demuxing: set by avformat_open_input()
1001 * - muxing: may be set by the caller before avformat_write_header()
1002 */
1003 char filename[1024];
1004
1005 /**
1006 * Position of the first frame of the component, in
1007 * AV_TIME_BASE fractional seconds. NEVER set this value directly:
1008 * It is deduced from the AVStream values.
1009 *
1010 * Demuxing only, set by libavformat.
1011 */
1012 int64_t start_time;
1013
1014 /**
1015 * Duration of the stream, in AV_TIME_BASE fractional
1016 * seconds. Only set this value if you know none of the individual stream
1017 * durations and also do not set any of them. This is deduced from the
1018 * AVStream values if not set.
1019 *
1020 * Demuxing only, set by libavformat.
1021 */
1022 int64_t duration;
1023
1024 /**
1025 * Total stream bitrate in bit/s, 0 if not
1026 * available. Never set it directly if the file_size and the
1027 * duration are known as Libav can compute it automatically.
1028 */
1029 int bit_rate;
1030
1031 unsigned int packet_size;
1032 int max_delay;
1033
1034 /**
1035 * Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
1036 * Set by the user before avformat_open_input() / avformat_write_header().
1037 */
1038 int flags;
1039 #define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
1040 #define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
1041 #define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
1042 #define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
1043 #define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container
1044 #define AVFMT_FLAG_NOPARSE 0x0020 ///< Do not use AVParsers, you also must set AVFMT_FLAG_NOFILLIN as the fillin code works on frames and no parsing -> no frames. Also seeking to frames can not work if parsing to find frame boundaries has been disabled
1045 #define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
1046 #define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
1047 #define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
1048 #define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
1049 /**
1050 * When muxing, try to avoid writing any random/volatile data to the output.
1051 * This includes any random IDs, real-time timestamps/dates, muxer version, etc.
1052 *
1053 * This flag is mainly intended for testing.
1054 */
1055 #define AVFMT_FLAG_BITEXACT 0x0400
1056
1057 /**
1058 * Maximum size of the data read from input for determining
1059 * the input container format.
1060 * Demuxing only, set by the caller before avformat_open_input().
1061 */
1062 unsigned int probesize;
1063
1064 /**
1065 * Maximum duration (in AV_TIME_BASE units) of the data read
1066 * from input in avformat_find_stream_info().
1067 * Demuxing only, set by the caller before avformat_find_stream_info().
1068 */
1069 int max_analyze_duration;
1070
1071 const uint8_t *key;
1072 int keylen;
1073
1074 unsigned int nb_programs;
1075 AVProgram **programs;
1076
1077 /**
1078 * Forced video codec_id.
1079 * Demuxing: Set by user.
1080 */
1081 enum AVCodecID video_codec_id;
1082
1083 /**
1084 * Forced audio codec_id.
1085 * Demuxing: Set by user.
1086 */
1087 enum AVCodecID audio_codec_id;
1088
1089 /**
1090 * Forced subtitle codec_id.
1091 * Demuxing: Set by user.
1092 */
1093 enum AVCodecID subtitle_codec_id;
1094
1095 /**
1096 * Maximum amount of memory in bytes to use for the index of each stream.
1097 * If the index exceeds this size, entries will be discarded as
1098 * needed to maintain a smaller size. This can lead to slower or less
1099 * accurate seeking (depends on demuxer).
1100 * Demuxers for which a full in-memory index is mandatory will ignore
1101 * this.
1102 * - muxing: unused
1103 * - demuxing: set by user
1104 */
1105 unsigned int max_index_size;
1106
1107 /**
1108 * Maximum amount of memory in bytes to use for buffering frames
1109 * obtained from realtime capture devices.
1110 */
1111 unsigned int max_picture_buffer;
1112
1113 /**
1114 * Number of chapters in AVChapter array.
1115 * When muxing, chapters are normally written in the file header,
1116 * so nb_chapters should normally be initialized before write_header
1117 * is called. Some muxers (e.g. mov and mkv) can also write chapters
1118 * in the trailer. To write chapters in the trailer, nb_chapters
1119 * must be zero when write_header is called and non-zero when
1120 * write_trailer is called.
1121 * - muxing: set by user
1122 * - demuxing: set by libavformat
1123 */
1124 unsigned int nb_chapters;
1125 AVChapter **chapters;
1126
1127 /**
1128 * Metadata that applies to the whole file.
1129 *
1130 * - demuxing: set by libavformat in avformat_open_input()
1131 * - muxing: may be set by the caller before avformat_write_header()
1132 *
1133 * Freed by libavformat in avformat_free_context().
1134 */
1135 AVDictionary *metadata;
1136
1137 /**
1138 * Start time of the stream in real world time, in microseconds
1139 * since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1140 * stream was captured at this real world time.
1141 * Muxing only, set by the caller before avformat_write_header().
1142 */
1143 int64_t start_time_realtime;
1144
1145 /**
1146 * The number of frames used for determining the framerate in
1147 * avformat_find_stream_info().
1148 * Demuxing only, set by the caller before avformat_find_stream_info().
1149 */
1150 int fps_probe_size;
1151
1152 /**
1153 * Error recognition; higher values will detect more errors but may
1154 * misdetect some more or less valid parts as errors.
1155 * Demuxing only, set by the caller before avformat_open_input().
1156 */
1157 int error_recognition;
1158
1159 /**
1160 * Custom interrupt callbacks for the I/O layer.
1161 *
1162 * demuxing: set by the user before avformat_open_input().
1163 * muxing: set by the user before avformat_write_header()
1164 * (mainly useful for AVFMT_NOFILE formats). The callback
1165 * should also be passed to avio_open2() if it's used to
1166 * open the file.
1167 */
1168 AVIOInterruptCB interrupt_callback;
1169
1170 /**
1171 * Flags to enable debugging.
1172 */
1173 int debug;
1174 #define FF_FDEBUG_TS 0x0001
1175
1176 /**
1177 * Maximum buffering duration for interleaving.
1178 *
1179 * To ensure all the streams are interleaved correctly,
1180 * av_interleaved_write_frame() will wait until it has at least one packet
1181 * for each stream before actually writing any packets to the output file.
1182 * When some streams are "sparse" (i.e. there are large gaps between
1183 * successive packets), this can result in excessive buffering.
1184 *
1185 * This field specifies the maximum difference between the timestamps of the
1186 * first and the last packet in the muxing queue, above which libavformat
1187 * will output a packet regardless of whether it has queued a packet for all
1188 * the streams.
1189 *
1190 * Muxing only, set by the caller before avformat_write_header().
1191 */
1192 int64_t max_interleave_delta;
1193
1194 /**
1195 * Allow non-standard and experimental extension
1196 * @see AVCodecContext.strict_std_compliance
1197 */
1198 int strict_std_compliance;
1199
1200 /**
1201 * Flags for the user to detect events happening on the file. Flags must
1202 * be cleared by the user once the event has been handled.
1203 * A combination of AVFMT_EVENT_FLAG_*.
1204 */
1205 int event_flags;
1206 #define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
1207
1208 /**
1209 * Maximum number of packets to read while waiting for the first timestamp.
1210 * Decoding only.
1211 */
1212 int max_ts_probe;
1213
1214 /**
1215 * Avoid negative timestamps during muxing.
1216 * Any value of the AVFMT_AVOID_NEG_TS_* constants.
1217 * Note, this only works when using av_interleaved_write_frame.
1218 * - muxing: Set by user
1219 * - demuxing: unused
1220 */
1221 int avoid_negative_ts;
1222 #define AVFMT_AVOID_NEG_TS_AUTO -1 ///< Enabled when required by target format
1223 #define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
1224 #define AVFMT_AVOID_NEG_TS_MAKE_ZERO 2 ///< Shift timestamps so that they start at 0
1225
1226 /**
1227 * An opaque field for libavformat internal usage.
1228 * Must not be accessed in any way by callers.
1229 */
1230 AVFormatInternal *internal;
1231
1232 /**
1233 * Arbitrary user data set by the caller.
1234 */
1235 void *opaque;
1236
1237 /**
1238 * A callback for opening new IO streams.
1239 *
1240 * Whenever a muxer or a demuxer needs to open an IO stream (typically from
1241 * avformat_open_input() for demuxers, but for certain formats can happen at
1242 * other times as well), it will call this callback to obtain an IO context.
1243 *
1244 * @param s the format context
1245 * @param pb on success, the newly opened IO context should be returned here
1246 * @param url the url to open
1247 * @param flags a combination of AVIO_FLAG_*
1248 * @param options a dictionary of additional options, with the same
1249 * semantics as in avio_open2()
1250 * @return 0 on success, a negative AVERROR code on failure
1251 *
1252 * @note Certain muxers and demuxers do nesting, i.e. they open one or more
1253 * additional internal format contexts. Thus the AVFormatContext pointer
1254 * passed to this callback may be different from the one facing the caller.
1255 * It will, however, have the same 'opaque' field.
1256 */
1257 int (*io_open)(struct AVFormatContext *s, AVIOContext **pb, const char *url,
1258 int flags, AVDictionary **options);
1259
1260 /**
1261 * A callback for closing the streams opened with AVFormatContext.io_open().
1262 */
1263 void (*io_close)(struct AVFormatContext *s, AVIOContext *pb);
1264 } AVFormatContext;
1265
1266 typedef struct AVPacketList {
1267 AVPacket pkt;
1268 struct AVPacketList *next;
1269 } AVPacketList;
1270
1271
1272 /**
1273 * @defgroup lavf_core Core functions
1274 * @ingroup libavf
1275 *
1276 * Functions for querying libavformat capabilities, allocating core structures,
1277 * etc.
1278 * @{
1279 */
1280
1281 /**
1282 * Return the LIBAVFORMAT_VERSION_INT constant.
1283 */
1284 unsigned avformat_version(void);
1285
1286 /**
1287 * Return the libavformat build-time configuration.
1288 */
1289 const char *avformat_configuration(void);
1290
1291 /**
1292 * Return the libavformat license.
1293 */
1294 const char *avformat_license(void);
1295
1296 /**
1297 * Initialize libavformat and register all the muxers, demuxers and
1298 * protocols. If you do not call this function, then you can select
1299 * exactly which formats you want to support.
1300 *
1301 * @see av_register_input_format()
1302 * @see av_register_output_format()
1303 * @see av_register_protocol()
1304 */
1305 void av_register_all(void);
1306
1307 void av_register_input_format(AVInputFormat *format);
1308 void av_register_output_format(AVOutputFormat *format);
1309
1310 /**
1311 * Do global initialization of network components. This is optional,
1312 * but recommended, since it avoids the overhead of implicitly
1313 * doing the setup for each session.
1314 *
1315 * Calling this function will become mandatory if using network
1316 * protocols at some major version bump.
1317 */
1318 int avformat_network_init(void);
1319
1320 /**
1321 * Undo the initialization done by avformat_network_init.
1322 */
1323 int avformat_network_deinit(void);
1324
1325 /**
1326 * If f is NULL, returns the first registered input format,
1327 * if f is non-NULL, returns the next registered input format after f
1328 * or NULL if f is the last one.
1329 */
1330 AVInputFormat *av_iformat_next(const AVInputFormat *f);
1331
1332 /**
1333 * If f is NULL, returns the first registered output format,
1334 * if f is non-NULL, returns the next registered output format after f
1335 * or NULL if f is the last one.
1336 */
1337 AVOutputFormat *av_oformat_next(const AVOutputFormat *f);
1338
1339 /**
1340 * Allocate an AVFormatContext.
1341 * avformat_free_context() can be used to free the context and everything
1342 * allocated by the framework within it.
1343 */
1344 AVFormatContext *avformat_alloc_context(void);
1345
1346 /**
1347 * Free an AVFormatContext and all its streams.
1348 * @param s context to free
1349 */
1350 void avformat_free_context(AVFormatContext *s);
1351
1352 /**
1353 * Get the AVClass for AVFormatContext. It can be used in combination with
1354 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
1355 *
1356 * @see av_opt_find().
1357 */
1358 const AVClass *avformat_get_class(void);
1359
1360 /**
1361 * Add a new stream to a media file.
1362 *
1363 * When demuxing, it is called by the demuxer in read_header(). If the
1364 * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
1365 * be called in read_packet().
1366 *
1367 * When muxing, should be called by the user before avformat_write_header().
1368 *
1369 * @param s media file handle
1370 * @param c If non-NULL, the AVCodecContext corresponding to the new stream
1371 * will be initialized to use this codec. This is needed for e.g. codec-specific
1372 * defaults to be set, so codec should be provided if it is known.
1373 *
1374 * @return newly created stream or NULL on error.
1375 */
1376 AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c);
1377
1378 /**
1379 * Allocate new information from stream.
1380 *
1381 * @param stream stream
1382 * @param type desired side information type
1383 * @param size side information size
1384 * @return pointer to fresh allocated data or NULL otherwise
1385 */
1386 uint8_t *av_stream_new_side_data(AVStream *stream,
1387 enum AVPacketSideDataType type, int size);
1388 /**
1389 * Get side information from stream.
1390 *
1391 * @param stream stream
1392 * @param type desired side information type
1393 * @param size pointer for side information size to store (optional)
1394 * @return pointer to data if present or NULL otherwise
1395 */
1396 uint8_t *av_stream_get_side_data(AVStream *stream,
1397 enum AVPacketSideDataType type, int *size);
1398
1399 AVProgram *av_new_program(AVFormatContext *s, int id);
1400
1401 /**
1402 * @}
1403 */
1404
1405
1406 /**
1407 * @addtogroup lavf_decoding
1408 * @{
1409 */
1410
1411 /**
1412 * Find AVInputFormat based on the short name of the input format.
1413 */
1414 AVInputFormat *av_find_input_format(const char *short_name);
1415
1416 /**
1417 * Guess the file format.
1418 *
1419 * @param pd data to be probed
1420 * @param is_opened Whether the file is already opened; determines whether
1421 * demuxers with or without AVFMT_NOFILE are probed.
1422 */
1423 AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened);
1424
1425 /**
1426 * Guess the file format.
1427 *
1428 * @param pd data to be probed
1429 * @param is_opened Whether the file is already opened; determines whether
1430 * demuxers with or without AVFMT_NOFILE are probed.
1431 * @param score_max A probe score larger that this is required to accept a
1432 * detection, the variable is set to the actual detection
1433 * score afterwards.
1434 * If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
1435 * to retry with a larger probe buffer.
1436 */
1437 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max);
1438
1439 /**
1440 * Probe a bytestream to determine the input format. Each time a probe returns
1441 * with a score that is too low, the probe buffer size is increased and another
1442 * attempt is made. When the maximum probe size is reached, the input format
1443 * with the highest score is returned.
1444 *
1445 * @param pb the bytestream to probe
1446 * @param fmt the input format is put here
1447 * @param filename the filename of the stream
1448 * @param logctx the log context
1449 * @param offset the offset within the bytestream to probe from
1450 * @param max_probe_size the maximum probe buffer size (zero for default)
1451 * @return 0 in case of success, a negative value corresponding to an
1452 * AVERROR code otherwise
1453 */
1454 int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
1455 const char *filename, void *logctx,
1456 unsigned int offset, unsigned int max_probe_size);
1457
1458 /**
1459 * Open an input stream and read the header. The codecs are not opened.
1460 * The stream must be closed with avformat_close_input().
1461 *
1462 * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
1463 * May be a pointer to NULL, in which case an AVFormatContext is allocated by this
1464 * function and written into ps.
1465 * Note that a user-supplied AVFormatContext will be freed on failure.
1466 * @param filename Name of the stream to open.
1467 * @param fmt If non-NULL, this parameter forces a specific input format.
1468 * Otherwise the format is autodetected.
1469 * @param options A dictionary filled with AVFormatContext and demuxer-private options.
1470 * On return this parameter will be destroyed and replaced with a dict containing
1471 * options that were not found. May be NULL.
1472 *
1473 * @return 0 on success, a negative AVERROR on failure.
1474 *
1475 * @note If you want to use custom IO, preallocate the format context and set its pb field.
1476 */
1477 int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options);
1478
1479 /**
1480 * Read packets of a media file to get stream information. This
1481 * is useful for file formats with no headers such as MPEG. This
1482 * function also computes the real framerate in case of MPEG-2 repeat
1483 * frame mode.
1484 * The logical file position is not changed by this function;
1485 * examined packets may be buffered for later processing.
1486 *
1487 * @param ic media file handle
1488 * @param options If non-NULL, an ic.nb_streams long array of pointers to
1489 * dictionaries, where i-th member contains options for
1490 * codec corresponding to i-th stream.
1491 * On return each dictionary will be filled with options that were not found.
1492 * @return >=0 if OK, AVERROR_xxx on error
1493 *
1494 * @note this function isn't guaranteed to open all the codecs, so
1495 * options being non-empty at return is a perfectly normal behavior.
1496 *
1497 * @todo Let the user decide somehow what information is needed so that
1498 * we do not waste time getting stuff the user does not need.
1499 */
1500 int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options);
1501
1502 /**
1503 * Find the "best" stream in the file.
1504 * The best stream is determined according to various heuristics as the most
1505 * likely to be what the user expects.
1506 * If the decoder parameter is non-NULL, av_find_best_stream will find the
1507 * default decoder for the stream's codec; streams for which no decoder can
1508 * be found are ignored.
1509 *
1510 * @param ic media file handle
1511 * @param type stream type: video, audio, subtitles, etc.
1512 * @param wanted_stream_nb user-requested stream number,
1513 * or -1 for automatic selection
1514 * @param related_stream try to find a stream related (eg. in the same
1515 * program) to this one, or -1 if none
1516 * @param decoder_ret if non-NULL, returns the decoder for the
1517 * selected stream
1518 * @param flags flags; none are currently defined
1519 * @return the non-negative stream number in case of success,
1520 * AVERROR_STREAM_NOT_FOUND if no stream with the requested type
1521 * could be found,
1522 * AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
1523 * @note If av_find_best_stream returns successfully and decoder_ret is not
1524 * NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
1525 */
1526 int av_find_best_stream(AVFormatContext *ic,
1527 enum AVMediaType type,
1528 int wanted_stream_nb,
1529 int related_stream,
1530 AVCodec **decoder_ret,
1531 int flags);
1532
1533 /**
1534 * Return the next frame of a stream.
1535 * This function returns what is stored in the file, and does not validate
1536 * that what is there are valid frames for the decoder. It will split what is
1537 * stored in the file into frames and return one for each call. It will not
1538 * omit invalid data between valid frames so as to give the decoder the maximum
1539 * information possible for decoding.
1540 *
1541 * If pkt->buf is NULL, then the packet is valid until the next
1542 * av_read_frame() or until avformat_close_input(). Otherwise the packet
1543 * is valid indefinitely. In both cases the packet must be freed with
1544 * av_packet_unref when it is no longer needed. For video, the packet contains
1545 * exactly one frame. For audio, it contains an integer number of frames if each
1546 * frame has a known fixed size (e.g. PCM or ADPCM data). If the audio frames
1547 * have a variable size (e.g. MPEG audio), then it contains one frame.
1548 *
1549 * pkt->pts, pkt->dts and pkt->duration are always set to correct
1550 * values in AVStream.time_base units (and guessed if the format cannot
1551 * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
1552 * has B-frames, so it is better to rely on pkt->dts if you do not
1553 * decompress the payload.
1554 *
1555 * @return 0 if OK, < 0 on error or end of file
1556 */
1557 int av_read_frame(AVFormatContext *s, AVPacket *pkt);
1558
1559 /**
1560 * Seek to the keyframe at timestamp.
1561 * 'timestamp' in 'stream_index'.
1562 *
1563 * @param s media file handle
1564 * @param stream_index If stream_index is (-1), a default
1565 * stream is selected, and timestamp is automatically converted
1566 * from AV_TIME_BASE units to the stream specific time_base.
1567 * @param timestamp Timestamp in AVStream.time_base units
1568 * or, if no stream is specified, in AV_TIME_BASE units.
1569 * @param flags flags which select direction and seeking mode
1570 * @return >= 0 on success
1571 */
1572 int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
1573 int flags);
1574
1575 /**
1576 * Seek to timestamp ts.
1577 * Seeking will be done so that the point from which all active streams
1578 * can be presented successfully will be closest to ts and within min/max_ts.
1579 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
1580 *
1581 * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
1582 * are the file position (this may not be supported by all demuxers).
1583 * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
1584 * in the stream with stream_index (this may not be supported by all demuxers).
1585 * Otherwise all timestamps are in units of the stream selected by stream_index
1586 * or if stream_index is -1, in AV_TIME_BASE units.
1587 * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
1588 * keyframes (this may not be supported by all demuxers).
1589 *
1590 * @param s media file handle
1591 * @param stream_index index of the stream which is used as time base reference
1592 * @param min_ts smallest acceptable timestamp
1593 * @param ts target timestamp
1594 * @param max_ts largest acceptable timestamp
1595 * @param flags flags
1596 * @return >=0 on success, error code otherwise
1597 *
1598 * @note This is part of the new seek API which is still under construction.
1599 * Thus do not use this yet. It may change at any time, do not expect
1600 * ABI compatibility yet!
1601 */
1602 int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
1603
1604 /**
1605 * Start playing a network-based stream (e.g. RTSP stream) at the
1606 * current position.
1607 */
1608 int av_read_play(AVFormatContext *s);
1609
1610 /**
1611 * Pause a network-based stream (e.g. RTSP stream).
1612 *
1613 * Use av_read_play() to resume it.
1614 */
1615 int av_read_pause(AVFormatContext *s);
1616
1617 /**
1618 * Close an opened input AVFormatContext. Free it and all its contents
1619 * and set *s to NULL.
1620 */
1621 void avformat_close_input(AVFormatContext **s);
1622 /**
1623 * @}
1624 */
1625
1626 #define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
1627 #define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
1628 #define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
1629 #define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
1630
1631 /**
1632 * @addtogroup lavf_encoding
1633 * @{
1634 */
1635 /**
1636 * Allocate the stream private data and write the stream header to
1637 * an output media file.
1638 *
1639 * @param s Media file handle, must be allocated with avformat_alloc_context().
1640 * Its oformat field must be set to the desired output format;
1641 * Its pb field must be set to an already opened AVIOContext.
1642 * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
1643 * On return this parameter will be destroyed and replaced with a dict containing
1644 * options that were not found. May be NULL.
1645 *
1646 * @return 0 on success, negative AVERROR on failure.
1647 *
1648 * @see av_opt_find, av_dict_set, avio_open, av_oformat_next.
1649 */
1650 int avformat_write_header(AVFormatContext *s, AVDictionary **options);
1651
1652 /**
1653 * Write a packet to an output media file.
1654 *
1655 * This function passes the packet directly to the muxer, without any buffering
1656 * or reordering. The caller is responsible for correctly interleaving the
1657 * packets if the format requires it. Callers that want libavformat to handle
1658 * the interleaving should call av_interleaved_write_frame() instead of this
1659 * function.
1660 *
1661 * @param s media file handle
1662 * @param pkt The packet containing the data to be written. Note that unlike
1663 * av_interleaved_write_frame(), this function does not take
1664 * ownership of the packet passed to it (though some muxers may make
1665 * an internal reference to the input packet).
1666 * <br>
1667 * This parameter can be NULL (at any time, not just at the end), in
1668 * order to immediately flush data buffered within the muxer, for
1669 * muxers that buffer up data internally before writing it to the
1670 * output.
1671 * <br>
1672 * Packet's @ref AVPacket.stream_index "stream_index" field must be
1673 * set to the index of the corresponding stream in @ref
1674 * AVFormatContext.streams "s->streams".
1675 * <br>
1676 * The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
1677 * must be set to correct values in the stream's timebase (unless the
1678 * output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
1679 * they can be set to AV_NOPTS_VALUE).
1680 * The dts for subsequent packets passed to this function must be strictly
1681 * increasing when compared in their respective timebases (unless the
1682 * output format is flagged with the AVFMT_TS_NONSTRICT, then they
1683 * merely have to be nondecreasing). @ref AVPacket.duration
1684 * "duration") should also be set if known.
1685 * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
1686 *
1687 * @see av_interleaved_write_frame()
1688 */
1689 int av_write_frame(AVFormatContext *s, AVPacket *pkt);
1690
1691 /**
1692 * Write a packet to an output media file ensuring correct interleaving.
1693 *
1694 * This function will buffer the packets internally as needed to make sure the
1695 * packets in the output file are properly interleaved in the order of
1696 * increasing dts. Callers doing their own interleaving should call
1697 * av_write_frame() instead of this function.
1698 *
1699 * @param s media file handle
1700 * @param pkt The packet containing the data to be written.
1701 * <br>
1702 * If the packet is reference-counted, this function will take
1703 * ownership of this reference and unreference it later when it sees
1704 * fit.
1705 * The caller must not access the data through this reference after
1706 * this function returns. If the packet is not reference-counted,
1707 * libavformat will make a copy.
1708 * <br>
1709 * This parameter can be NULL (at any time, not just at the end), to
1710 * flush the interleaving queues.
1711 * <br>
1712 * Packet's @ref AVPacket.stream_index "stream_index" field must be
1713 * set to the index of the corresponding stream in @ref
1714 * AVFormatContext.streams "s->streams".
1715 * <br>
1716 * The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
1717 * must be set to correct values in the stream's timebase (unless the
1718 * output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
1719 * they can be set to AV_NOPTS_VALUE).
1720 * The dts for subsequent packets in one stream must be strictly
1721 * increasing (unless the output format is flagged with the
1722 * AVFMT_TS_NONSTRICT, then they merely have to be nondecreasing).
1723 * @ref AVPacket.duration "duration") should also be set if known.
1724 *
1725 * @return 0 on success, a negative AVERROR on error. Libavformat will always
1726 * take care of freeing the packet, even if this function fails.
1727 *
1728 * @see av_write_frame(), AVFormatContext.max_interleave_delta
1729 */
1730 int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
1731
1732 /**
1733 * Write the stream trailer to an output media file and free the
1734 * file private data.
1735 *
1736 * May only be called after a successful call to avformat_write_header.
1737 *
1738 * @param s media file handle
1739 * @return 0 if OK, AVERROR_xxx on error
1740 */
1741 int av_write_trailer(AVFormatContext *s);
1742
1743 /**
1744 * Return the output format in the list of registered output formats
1745 * which best matches the provided parameters, or return NULL if
1746 * there is no match.
1747 *
1748 * @param short_name if non-NULL checks if short_name matches with the
1749 * names of the registered formats
1750 * @param filename if non-NULL checks if filename terminates with the
1751 * extensions of the registered formats
1752 * @param mime_type if non-NULL checks if mime_type matches with the
1753 * MIME type of the registered formats
1754 */
1755 AVOutputFormat *av_guess_format(const char *short_name,
1756 const char *filename,
1757 const char *mime_type);
1758
1759 /**
1760 * Guess the codec ID based upon muxer and filename.
1761 */
1762 enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
1763 const char *filename, const char *mime_type,
1764 enum AVMediaType type);
1765
1766 /**
1767 * @}
1768 */
1769
1770
1771 /**
1772 * @defgroup lavf_misc Utility functions
1773 * @ingroup libavf
1774 * @{
1775 *
1776 * Miscellaneous utility functions related to both muxing and demuxing
1777 * (or neither).
1778 */
1779
1780 /**
1781 * Send a nice hexadecimal dump of a buffer to the specified file stream.
1782 *
1783 * @param f The file stream pointer where the dump should be sent to.
1784 * @param buf buffer
1785 * @param size buffer size
1786 *
1787 * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
1788 */
1789 void av_hex_dump(FILE *f, const uint8_t *buf, int size);
1790
1791 /**
1792 * Send a nice hexadecimal dump of a buffer to the log.
1793 *
1794 * @param avcl A pointer to an arbitrary struct of which the first field is a
1795 * pointer to an AVClass struct.
1796 * @param level The importance level of the message, lower values signifying
1797 * higher importance.
1798 * @param buf buffer
1799 * @param size buffer size
1800 *
1801 * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
1802 */
1803 void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
1804
1805 /**
1806 * Send a nice dump of a packet to the specified file stream.
1807 *
1808 * @param f The file stream pointer where the dump should be sent to.
1809 * @param pkt packet to dump
1810 * @param dump_payload True if the payload must be displayed, too.
1811 * @param st AVStream that the packet belongs to
1812 */
1813 void av_pkt_dump2(FILE *f, AVPacket *pkt, int dump_payload, AVStream *st);
1814
1815
1816 /**
1817 * Send a nice dump of a packet to the log.
1818 *
1819 * @param avcl A pointer to an arbitrary struct of which the first field is a
1820 * pointer to an AVClass struct.
1821 * @param level The importance level of the message, lower values signifying
1822 * higher importance.
1823 * @param pkt packet to dump
1824 * @param dump_payload True if the payload must be displayed, too.
1825 * @param st AVStream that the packet belongs to
1826 */
1827 void av_pkt_dump_log2(void *avcl, int level, AVPacket *pkt, int dump_payload,
1828 AVStream *st);
1829
1830 /**
1831 * Get the AVCodecID for the given codec tag tag.
1832 * If no codec id is found returns AV_CODEC_ID_NONE.
1833 *
1834 * @param tags list of supported codec_id-codec_tag pairs, as stored
1835 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
1836 * @param tag codec tag to match to a codec ID
1837 */
1838 enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
1839
1840 /**
1841 * Get the codec tag for the given codec id id.
1842 * If no codec tag is found returns 0.
1843 *
1844 * @param tags list of supported codec_id-codec_tag pairs, as stored
1845 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
1846 * @param id codec ID to match to a codec tag
1847 */
1848 unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id);
1849
1850 int av_find_default_stream_index(AVFormatContext *s);
1851
1852 /**
1853 * Get the index for a specific timestamp.
1854 *
1855 * @param st stream that the timestamp belongs to
1856 * @param timestamp timestamp to retrieve the index for
1857 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
1858 * to the timestamp which is <= the requested one, if backward
1859 * is 0, then it will be >=
1860 * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
1861 * @return < 0 if no such timestamp could be found
1862 */
1863 int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
1864
1865 /**
1866 * Add an index entry into a sorted list. Update the entry if the list
1867 * already contains it.
1868 *
1869 * @param timestamp timestamp in the time base of the given stream
1870 */
1871 int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
1872 int size, int distance, int flags);
1873
1874
1875 /**
1876 * Split a URL string into components.
1877 *
1878 * The pointers to buffers for storing individual components may be null,
1879 * in order to ignore that component. Buffers for components not found are
1880 * set to empty strings. If the port is not found, it is set to a negative
1881 * value.
1882 *
1883 * @param proto the buffer for the protocol
1884 * @param proto_size the size of the proto buffer
1885 * @param authorization the buffer for the authorization
1886 * @param authorization_size the size of the authorization buffer
1887 * @param hostname the buffer for the host name
1888 * @param hostname_size the size of the hostname buffer
1889 * @param port_ptr a pointer to store the port number in
1890 * @param path the buffer for the path
1891 * @param path_size the size of the path buffer
1892 * @param url the URL to split
1893 */
1894 void av_url_split(char *proto, int proto_size,
1895 char *authorization, int authorization_size,
1896 char *hostname, int hostname_size,
1897 int *port_ptr,
1898 char *path, int path_size,
1899 const char *url);
1900
1901
1902 /**
1903 * Print detailed information about the input or output format, such as
1904 * duration, bitrate, streams, container, programs, metadata, side data,
1905 * codec and time base.
1906 *
1907 * @param ic the context to analyze
1908 * @param index the index to print, if you have multiple inputs or outputs
1909 * @param url the URL to print, such as source or destination file
1910 * @param is_output whether the context is input or ouput
1911 */
1912 void av_dump_format(AVFormatContext *ic,
1913 int index,
1914 const char *url,
1915 int is_output);
1916
1917 /**
1918 * Return in 'buf' the path with '%d' replaced by a number.
1919 *
1920 * Also handles the '%0nd' format where 'n' is the total number
1921 * of digits and '%%'.
1922 *
1923 * @param buf destination buffer
1924 * @param buf_size destination buffer size
1925 * @param path numbered sequence string
1926 * @param number frame number
1927 * @return 0 if OK, -1 on format error
1928 */
1929 int av_get_frame_filename(char *buf, int buf_size,
1930 const char *path, int number);
1931
1932 /**
1933 * Check whether filename actually is a numbered sequence generator.
1934 *
1935 * @param filename possible numbered sequence string
1936 * @return 1 if a valid numbered sequence string, 0 otherwise
1937 */
1938 int av_filename_number_test(const char *filename);
1939
1940 /**
1941 * Generate an SDP for an RTP session.
1942 *
1943 * Note, this overwrites the id values of AVStreams in the muxer contexts
1944 * for getting unique dynamic payload types.
1945 *
1946 * @param ac array of AVFormatContexts describing the RTP streams. If the
1947 * array is composed by only one context, such context can contain
1948 * multiple AVStreams (one AVStream per RTP stream). Otherwise,
1949 * all the contexts in the array (an AVCodecContext per RTP stream)
1950 * must contain only one AVStream.
1951 * @param n_files number of AVCodecContexts contained in ac
1952 * @param buf buffer where the SDP will be stored (must be allocated by
1953 * the caller)
1954 * @param size the size of the buffer
1955 * @return 0 if OK, AVERROR_xxx on error
1956 */
1957 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
1958
1959 /**
1960 * Return a positive value if the given filename has one of the given
1961 * extensions, 0 otherwise.
1962 *
1963 * @param filename file name to check against the given extensions
1964 * @param extensions a comma-separated list of filename extensions
1965 */
1966 int av_match_ext(const char *filename, const char *extensions);
1967
1968 /**
1969 * Test if the given container can store a codec.
1970 *
1971 * @param ofmt container to check for compatibility
1972 * @param codec_id codec to potentially store in container
1973 * @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
1974 *
1975 * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
1976 * A negative number if this information is not available.
1977 */
1978 int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id,
1979 int std_compliance);
1980
1981 /**
1982 * @defgroup riff_fourcc RIFF FourCCs
1983 * @{
1984 * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
1985 * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
1986 * following code:
1987 * @code
1988 * uint32_t tag = MKTAG('H', '2', '6', '4');
1989 * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
1990 * enum AVCodecID id = av_codec_get_id(table, tag);
1991 * @endcode
1992 */
1993 /**
1994 * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
1995 */
1996 const struct AVCodecTag *avformat_get_riff_video_tags(void);
1997 /**
1998 * @return the table mapping RIFF FourCCs for audio to AVCodecID.
1999 */
2000 const struct AVCodecTag *avformat_get_riff_audio_tags(void);
2001 /**
2002 * @}
2003 */
2004
2005 /**
2006 * @}
2007 */
2008
2009 #endif /* AVFORMAT_AVFORMAT_H */