FFmpeg  2.8.17
avformat.h
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1 /*
2  * copyright (c) 2001 Fabrice Bellard
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
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 Libavformat 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  * It is possible to configure lavf 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  * @section urls
82  * URL strings in libavformat are made of a scheme/protocol, a ':', and a
83  * scheme specific string. URLs without a scheme and ':' used for local files
84  * are supported but deprecated. "file:" should be used for local files.
85  *
86  * It is important that the scheme string is not taken from untrusted
87  * sources without checks.
88  *
89  * Note that some schemes/protocols are quite powerful, allowing access to
90  * both local and remote files, parts of them, concatenations of them, local
91  * audio and video devices and so on.
92  *
93  * @defgroup lavf_decoding Demuxing
94  * @{
95  * Demuxers read a media file and split it into chunks of data (@em packets). A
96  * @ref AVPacket "packet" contains one or more encoded frames which belongs to a
97  * single elementary stream. In the lavf API this process is represented by the
98  * avformat_open_input() function for opening a file, av_read_frame() for
99  * reading a single packet and finally avformat_close_input(), which does the
100  * cleanup.
101  *
102  * @section lavf_decoding_open Opening a media file
103  * The minimum information required to open a file is its URL, which
104  * is passed to avformat_open_input(), as in the following code:
105  * @code
106  * const char *url = "file:in.mp3";
107  * AVFormatContext *s = NULL;
108  * int ret = avformat_open_input(&s, url, NULL, NULL);
109  * if (ret < 0)
110  * abort();
111  * @endcode
112  * The above code attempts to allocate an AVFormatContext, open the
113  * specified file (autodetecting the format) and read the header, exporting the
114  * information stored there into s. Some formats do not have a header or do not
115  * store enough information there, so it is recommended that you call the
116  * avformat_find_stream_info() function which tries to read and decode a few
117  * frames to find missing information.
118  *
119  * In some cases you might want to preallocate an AVFormatContext yourself with
120  * avformat_alloc_context() and do some tweaking on it before passing it to
121  * avformat_open_input(). One such case is when you want to use custom functions
122  * for reading input data instead of lavf internal I/O layer.
123  * To do that, create your own AVIOContext with avio_alloc_context(), passing
124  * your reading callbacks to it. Then set the @em pb field of your
125  * AVFormatContext to newly created AVIOContext.
126  *
127  * Since the format of the opened file is in general not known until after
128  * avformat_open_input() has returned, it is not possible to set demuxer private
129  * options on a preallocated context. Instead, the options should be passed to
130  * avformat_open_input() wrapped in an AVDictionary:
131  * @code
132  * AVDictionary *options = NULL;
133  * av_dict_set(&options, "video_size", "640x480", 0);
134  * av_dict_set(&options, "pixel_format", "rgb24", 0);
135  *
136  * if (avformat_open_input(&s, url, NULL, &options) < 0)
137  * abort();
138  * av_dict_free(&options);
139  * @endcode
140  * This code passes the private options 'video_size' and 'pixel_format' to the
141  * demuxer. They would be necessary for e.g. the rawvideo demuxer, since it
142  * cannot know how to interpret raw video data otherwise. If the format turns
143  * out to be something different than raw video, those options will not be
144  * recognized by the demuxer and therefore will not be applied. Such unrecognized
145  * options are then returned in the options dictionary (recognized options are
146  * consumed). The calling program can handle such unrecognized options as it
147  * wishes, e.g.
148  * @code
149  * AVDictionaryEntry *e;
150  * if (e = av_dict_get(options, "", NULL, AV_DICT_IGNORE_SUFFIX)) {
151  * fprintf(stderr, "Option %s not recognized by the demuxer.\n", e->key);
152  * abort();
153  * }
154  * @endcode
155  *
156  * After you have finished reading the file, you must close it with
157  * avformat_close_input(). It will free everything associated with the file.
158  *
159  * @section lavf_decoding_read Reading from an opened file
160  * Reading data from an opened AVFormatContext is done by repeatedly calling
161  * av_read_frame() on it. Each call, if successful, will return an AVPacket
162  * containing encoded data for one AVStream, identified by
163  * AVPacket.stream_index. This packet may be passed straight into the libavcodec
164  * decoding functions avcodec_decode_video2(), avcodec_decode_audio4() or
165  * avcodec_decode_subtitle2() if the caller wishes to decode the data.
166  *
167  * AVPacket.pts, AVPacket.dts and AVPacket.duration timing information will be
168  * set if known. They may also be unset (i.e. AV_NOPTS_VALUE for
169  * pts/dts, 0 for duration) if the stream does not provide them. The timing
170  * information will be in AVStream.time_base units, i.e. it has to be
171  * multiplied by the timebase to convert them to seconds.
172  *
173  * If AVPacket.buf is set on the returned packet, then the packet is
174  * allocated dynamically and the user may keep it indefinitely.
175  * Otherwise, if AVPacket.buf is NULL, the packet data is backed by a
176  * static storage somewhere inside the demuxer and the packet is only valid
177  * until the next av_read_frame() call or closing the file. If the caller
178  * requires a longer lifetime, av_dup_packet() will make an av_malloc()ed copy
179  * of it.
180  * In both cases, the packet must be freed with av_free_packet() when it is no
181  * longer needed.
182  *
183  * @section lavf_decoding_seek Seeking
184  * @}
185  *
186  * @defgroup lavf_encoding Muxing
187  * @{
188  * Muxers take encoded data in the form of @ref AVPacket "AVPackets" and write
189  * it into files or other output bytestreams in the specified container format.
190  *
191  * The main API functions for muxing are avformat_write_header() for writing the
192  * file header, av_write_frame() / av_interleaved_write_frame() for writing the
193  * packets and av_write_trailer() for finalizing the file.
194  *
195  * At the beginning of the muxing process, the caller must first call
196  * avformat_alloc_context() to create a muxing context. The caller then sets up
197  * the muxer by filling the various fields in this context:
198  *
199  * - The @ref AVFormatContext.oformat "oformat" field must be set to select the
200  * muxer that will be used.
201  * - Unless the format is of the AVFMT_NOFILE type, the @ref AVFormatContext.pb
202  * "pb" field must be set to an opened IO context, either returned from
203  * avio_open2() or a custom one.
204  * - Unless the format is of the AVFMT_NOSTREAMS type, at least one stream must
205  * be created with the avformat_new_stream() function. The caller should fill
206  * the @ref AVStream.codec "stream codec context" information, such as the
207  * codec @ref AVCodecContext.codec_type "type", @ref AVCodecContext.codec_id
208  * "id" and other parameters (e.g. width / height, the pixel or sample format,
209  * etc.) as known. The @ref AVStream.time_base "stream timebase" should
210  * be set to the timebase that the caller desires to use for this stream (note
211  * that the timebase actually used by the muxer can be different, as will be
212  * described later).
213  * - It is advised to manually initialize only the relevant fields in
214  * AVCodecContext, rather than using @ref avcodec_copy_context() during
215  * remuxing: there is no guarantee that the codec context values remain valid
216  * for both input and output format contexts.
217  * - The caller may fill in additional information, such as @ref
218  * AVFormatContext.metadata "global" or @ref AVStream.metadata "per-stream"
219  * metadata, @ref AVFormatContext.chapters "chapters", @ref
220  * AVFormatContext.programs "programs", etc. as described in the
221  * AVFormatContext documentation. Whether such information will actually be
222  * stored in the output depends on what the container format and the muxer
223  * support.
224  *
225  * When the muxing context is fully set up, the caller must call
226  * avformat_write_header() to initialize the muxer internals and write the file
227  * header. Whether anything actually is written to the IO context at this step
228  * depends on the muxer, but this function must always be called. Any muxer
229  * private options must be passed in the options parameter to this function.
230  *
231  * The data is then sent to the muxer by repeatedly calling av_write_frame() or
232  * av_interleaved_write_frame() (consult those functions' documentation for
233  * discussion on the difference between them; only one of them may be used with
234  * a single muxing context, they should not be mixed). Do note that the timing
235  * information on the packets sent to the muxer must be in the corresponding
236  * AVStream's timebase. That timebase is set by the muxer (in the
237  * avformat_write_header() step) and may be different from the timebase
238  * requested by the caller.
239  *
240  * Once all the data has been written, the caller must call av_write_trailer()
241  * to flush any buffered packets and finalize the output file, then close the IO
242  * context (if any) and finally free the muxing context with
243  * avformat_free_context().
244  * @}
245  *
246  * @defgroup lavf_io I/O Read/Write
247  * @{
248  * @section lavf_io_dirlist Directory listing
249  * The directory listing API makes it possible to list files on remote servers.
250  *
251  * Some of possible use cases:
252  * - an "open file" dialog to choose files from a remote location,
253  * - a recursive media finder providing a player with an ability to play all
254  * files from a given directory.
255  *
256  * @subsection lavf_io_dirlist_open Opening a directory
257  * At first, a directory needs to be opened by calling avio_open_dir()
258  * supplied with a URL and, optionally, ::AVDictionary containing
259  * protocol-specific parameters. The function returns zero or positive
260  * integer and allocates AVIODirContext on success.
261  *
262  * @code
263  * AVIODirContext *ctx = NULL;
264  * if (avio_open_dir(&ctx, "smb://example.com/some_dir", NULL) < 0) {
265  * fprintf(stderr, "Cannot open directory.\n");
266  * abort();
267  * }
268  * @endcode
269  *
270  * This code tries to open a sample directory using smb protocol without
271  * any additional parameters.
272  *
273  * @subsection lavf_io_dirlist_read Reading entries
274  * Each directory's entry (i.e. file, another directory, anything else
275  * within ::AVIODirEntryType) is represented by AVIODirEntry.
276  * Reading consecutive entries from an opened AVIODirContext is done by
277  * repeatedly calling avio_read_dir() on it. Each call returns zero or
278  * positive integer if successful. Reading can be stopped right after the
279  * NULL entry has been read -- it means there are no entries left to be
280  * read. The following code reads all entries from a directory associated
281  * with ctx and prints their names to standard output.
282  * @code
283  * AVIODirEntry *entry = NULL;
284  * for (;;) {
285  * if (avio_read_dir(ctx, &entry) < 0) {
286  * fprintf(stderr, "Cannot list directory.\n");
287  * abort();
288  * }
289  * if (!entry)
290  * break;
291  * printf("%s\n", entry->name);
292  * avio_free_directory_entry(&entry);
293  * }
294  * @endcode
295  * @}
296  *
297  * @defgroup lavf_codec Demuxers
298  * @{
299  * @defgroup lavf_codec_native Native Demuxers
300  * @{
301  * @}
302  * @defgroup lavf_codec_wrappers External library wrappers
303  * @{
304  * @}
305  * @}
306  * @defgroup lavf_protos I/O Protocols
307  * @{
308  * @}
309  * @defgroup lavf_internal Internal
310  * @{
311  * @}
312  * @}
313  *
314  */
315 
316 #include <time.h>
317 #include <stdio.h> /* FILE */
318 #include "libavcodec/avcodec.h"
319 #include "libavutil/dict.h"
320 #include "libavutil/log.h"
321 
322 #include "avio.h"
323 #include "libavformat/version.h"
324 
325 struct AVFormatContext;
326 
327 struct AVDeviceInfoList;
329 
330 /**
331  * @defgroup metadata_api Public Metadata API
332  * @{
333  * @ingroup libavf
334  * The metadata API allows libavformat to export metadata tags to a client
335  * application when demuxing. Conversely it allows a client application to
336  * set metadata when muxing.
337  *
338  * Metadata is exported or set as pairs of key/value strings in the 'metadata'
339  * fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
340  * using the @ref lavu_dict "AVDictionary" API. Like all strings in FFmpeg,
341  * metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
342  * exported by demuxers isn't checked to be valid UTF-8 in most cases.
343  *
344  * Important concepts to keep in mind:
345  * - Keys are unique; there can never be 2 tags with the same key. This is
346  * also meant semantically, i.e., a demuxer should not knowingly produce
347  * several keys that are literally different but semantically identical.
348  * E.g., key=Author5, key=Author6. In this example, all authors must be
349  * placed in the same tag.
350  * - Metadata is flat, not hierarchical; there are no subtags. If you
351  * want to store, e.g., the email address of the child of producer Alice
352  * and actor Bob, that could have key=alice_and_bobs_childs_email_address.
353  * - Several modifiers can be applied to the tag name. This is done by
354  * appending a dash character ('-') and the modifier name in the order
355  * they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
356  * - language -- a tag whose value is localized for a particular language
357  * is appended with the ISO 639-2/B 3-letter language code.
358  * For example: Author-ger=Michael, Author-eng=Mike
359  * The original/default language is in the unqualified "Author" tag.
360  * A demuxer should set a default if it sets any translated tag.
361  * - sorting -- a modified version of a tag that should be used for
362  * sorting will have '-sort' appended. E.g. artist="The Beatles",
363  * artist-sort="Beatles, The".
364  * - Some protocols and demuxers support metadata updates. After a successful
365  * call to av_read_packet(), AVFormatContext.event_flags or AVStream.event_flags
366  * will be updated to indicate if metadata changed. In order to detect metadata
367  * changes on a stream, you need to loop through all streams in the AVFormatContext
368  * and check their individual event_flags.
369  *
370  * - Demuxers attempt to export metadata in a generic format, however tags
371  * with no generic equivalents are left as they are stored in the container.
372  * Follows a list of generic tag names:
373  *
374  @verbatim
375  album -- name of the set this work belongs to
376  album_artist -- main creator of the set/album, if different from artist.
377  e.g. "Various Artists" for compilation albums.
378  artist -- main creator of the work
379  comment -- any additional description of the file.
380  composer -- who composed the work, if different from artist.
381  copyright -- name of copyright holder.
382  creation_time-- date when the file was created, preferably in ISO 8601.
383  date -- date when the work was created, preferably in ISO 8601.
384  disc -- number of a subset, e.g. disc in a multi-disc collection.
385  encoder -- name/settings of the software/hardware that produced the file.
386  encoded_by -- person/group who created the file.
387  filename -- original name of the file.
388  genre -- <self-evident>.
389  language -- main language in which the work is performed, preferably
390  in ISO 639-2 format. Multiple languages can be specified by
391  separating them with commas.
392  performer -- artist who performed the work, if different from artist.
393  E.g for "Also sprach Zarathustra", artist would be "Richard
394  Strauss" and performer "London Philharmonic Orchestra".
395  publisher -- name of the label/publisher.
396  service_name -- name of the service in broadcasting (channel name).
397  service_provider -- name of the service provider in broadcasting.
398  title -- name of the work.
399  track -- number of this work in the set, can be in form current/total.
400  variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
401  @endverbatim
402  *
403  * Look in the examples section for an application example how to use the Metadata API.
404  *
405  * @}
406  */
407 
408 /* packet functions */
409 
410 
411 /**
412  * Allocate and read the payload of a packet and initialize its
413  * fields with default values.
414  *
415  * @param s associated IO context
416  * @param pkt packet
417  * @param size desired payload size
418  * @return >0 (read size) if OK, AVERROR_xxx otherwise
419  */
420 int av_get_packet(AVIOContext *s, AVPacket *pkt, int size);
421 
422 
423 /**
424  * Read data and append it to the current content of the AVPacket.
425  * If pkt->size is 0 this is identical to av_get_packet.
426  * Note that this uses av_grow_packet and thus involves a realloc
427  * which is inefficient. Thus this function should only be used
428  * when there is no reasonable way to know (an upper bound of)
429  * the final size.
430  *
431  * @param s associated IO context
432  * @param pkt packet
433  * @param size amount of data to read
434  * @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
435  * will not be lost even if an error occurs.
436  */
437 int av_append_packet(AVIOContext *s, AVPacket *pkt, int size);
438 
439 #if FF_API_LAVF_FRAC
440 /*************************************************/
441 /* fractional numbers for exact pts handling */
442 
443 /**
444  * The exact value of the fractional number is: 'val + num / den'.
445  * num is assumed to be 0 <= num < den.
446  */
447 typedef struct AVFrac {
448  int64_t val, num, den;
449 } AVFrac;
450 #endif
451 
452 /*************************************************/
453 /* input/output formats */
454 
455 struct AVCodecTag;
456 
457 /**
458  * This structure contains the data a format has to probe a file.
459  */
460 typedef struct AVProbeData {
461  const char *filename;
462  unsigned char *buf; /**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */
463  int buf_size; /**< Size of buf except extra allocated bytes */
464  const char *mime_type; /**< mime_type, when known. */
465 } AVProbeData;
466 
467 #define AVPROBE_SCORE_RETRY (AVPROBE_SCORE_MAX/4)
468 #define AVPROBE_SCORE_STREAM_RETRY (AVPROBE_SCORE_MAX/4-1)
469 
470 #define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
471 #define AVPROBE_SCORE_MIME 75 ///< score for file mime type
472 #define AVPROBE_SCORE_MAX 100 ///< maximum score
473 
474 #define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
475 
476 /// Demuxer will use avio_open, no opened file should be provided by the caller.
477 #define AVFMT_NOFILE 0x0001
478 #define AVFMT_NEEDNUMBER 0x0002 /**< Needs '%d' in filename. */
479 #define AVFMT_SHOW_IDS 0x0008 /**< Show format stream IDs numbers. */
480 #define AVFMT_RAWPICTURE 0x0020 /**< Format wants AVPicture structure for
481  raw picture data. */
482 #define AVFMT_GLOBALHEADER 0x0040 /**< Format wants global header. */
483 #define AVFMT_NOTIMESTAMPS 0x0080 /**< Format does not need / have any timestamps. */
484 #define AVFMT_GENERIC_INDEX 0x0100 /**< Use generic index building code. */
485 #define AVFMT_TS_DISCONT 0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
486 #define AVFMT_VARIABLE_FPS 0x0400 /**< Format allows variable fps. */
487 #define AVFMT_NODIMENSIONS 0x0800 /**< Format does not need width/height */
488 #define AVFMT_NOSTREAMS 0x1000 /**< Format does not require any streams */
489 #define AVFMT_NOBINSEARCH 0x2000 /**< Format does not allow to fall back on binary search via read_timestamp */
490 #define AVFMT_NOGENSEARCH 0x4000 /**< Format does not allow to fall back on generic search */
491 #define AVFMT_NO_BYTE_SEEK 0x8000 /**< Format does not allow seeking by bytes */
492 #define AVFMT_ALLOW_FLUSH 0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
493 #if LIBAVFORMAT_VERSION_MAJOR <= 54
494 #define AVFMT_TS_NONSTRICT 0x8020000 //we try to be compatible to the ABIs of ffmpeg and major forks
495 #else
496 #define AVFMT_TS_NONSTRICT 0x20000
497 #endif
498  /**< Format does not require strictly
499  increasing timestamps, but they must
500  still be monotonic */
501 #define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative
502  timestamps. If not set the timestamp
503  will be shifted in av_write_frame and
504  av_interleaved_write_frame so they
505  start from 0.
506  The user or muxer can override this through
507  AVFormatContext.avoid_negative_ts
508  */
509 
510 #define AVFMT_SEEK_TO_PTS 0x4000000 /**< Seeking is based on PTS */
511 
512 /**
513  * @addtogroup lavf_encoding
514  * @{
515  */
516 typedef struct AVOutputFormat {
517  const char *name;
518  /**
519  * Descriptive name for the format, meant to be more human-readable
520  * than name. You should use the NULL_IF_CONFIG_SMALL() macro
521  * to define it.
522  */
523  const char *long_name;
524  const char *mime_type;
525  const char *extensions; /**< comma-separated filename extensions */
526  /* output support */
527  enum AVCodecID audio_codec; /**< default audio codec */
528  enum AVCodecID video_codec; /**< default video codec */
529  enum AVCodecID subtitle_codec; /**< default subtitle codec */
530  /**
531  * can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_RAWPICTURE,
532  * AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
533  * AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
534  * AVFMT_TS_NONSTRICT
535  */
536  int flags;
538  /**
539  * List of supported codec_id-codec_tag pairs, ordered by "better
540  * choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
541  */
542  const struct AVCodecTag * const *codec_tag;
543 
545  const AVClass *priv_class; ///< AVClass for the private context
546 
547  /*****************************************************************
548  * No fields below this line are part of the public API. They
549  * may not be used outside of libavformat and can be changed and
550  * removed at will.
551  * New public fields should be added right above.
552  *****************************************************************
553  */
554  struct AVOutputFormat *next;
555  /**
556  * size of private data so that it can be allocated in the wrapper
557  */
558  int priv_data_size;
559 
560  int (*write_header)(struct AVFormatContext *);
561  /**
562  * Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,
563  * pkt can be NULL in order to flush data buffered in the muxer.
564  * When flushing, return 0 if there still is more data to flush,
565  * or 1 if everything was flushed and there is no more buffered
566  * data.
567  */
568  int (*write_packet)(struct AVFormatContext *, AVPacket *pkt);
569  int (*write_trailer)(struct AVFormatContext *);
570  /**
571  * Currently only used to set pixel format if not YUV420P.
572  */
573  int (*interleave_packet)(struct AVFormatContext *, AVPacket *out,
574  AVPacket *in, int flush);
575  /**
576  * Test if the given codec can be stored in this container.
577  *
578  * @return 1 if the codec is supported, 0 if it is not.
579  * A negative number if unknown.
580  * MKTAG('A', 'P', 'I', 'C') if the codec is only supported as AV_DISPOSITION_ATTACHED_PIC
581  */
582  int (*query_codec)(enum AVCodecID id, int std_compliance);
583 
584  void (*get_output_timestamp)(struct AVFormatContext *s, int stream,
585  int64_t *dts, int64_t *wall);
586  /**
587  * Allows sending messages from application to device.
588  */
589  int (*control_message)(struct AVFormatContext *s, int type,
590  void *data, size_t data_size);
591 
592  /**
593  * Write an uncoded AVFrame.
594  *
595  * See av_write_uncoded_frame() for details.
596  *
597  * The library will free *frame afterwards, but the muxer can prevent it
598  * by setting the pointer to NULL.
599  */
600  int (*write_uncoded_frame)(struct AVFormatContext *, int stream_index,
601  AVFrame **frame, unsigned flags);
602  /**
603  * Returns device list with it properties.
604  * @see avdevice_list_devices() for more details.
605  */
606  int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list);
607  /**
608  * Initialize device capabilities submodule.
609  * @see avdevice_capabilities_create() for more details.
610  */
611  int (*create_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);
612  /**
613  * Free device capabilities submodule.
614  * @see avdevice_capabilities_free() for more details.
615  */
616  int (*free_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);
617  enum AVCodecID data_codec; /**< default data codec */
618  /**
619  * Initialize format. May allocate data here, and set any AVFormatContext or
620  * AVStream parameters that need to be set before packets are sent.
621  * This method must not write output.
622  *
623  * Return 0 if streams were fully configured, 1 if not, negative AVERROR on failure
624  *
625  * Any allocations made here must be freed in deinit().
626  */
627  int (*init)(struct AVFormatContext *);
628  /**
629  * Deinitialize format. If present, this is called whenever the muxer is being
630  * destroyed, regardless of whether or not the header has been written.
631  *
632  * If a trailer is being written, this is called after write_trailer().
633  *
634  * This is called if init() fails as well.
635  */
636  void (*deinit)(struct AVFormatContext *);
638 /**
639  * @}
640  */
641 
642 /**
643  * @addtogroup lavf_decoding
644  * @{
645  */
646 typedef struct AVInputFormat {
647  /**
648  * A comma separated list of short names for the format. New names
649  * may be appended with a minor bump.
650  */
651  const char *name;
652 
653  /**
654  * Descriptive name for the format, meant to be more human-readable
655  * than name. You should use the NULL_IF_CONFIG_SMALL() macro
656  * to define it.
657  */
658  const char *long_name;
660  /**
661  * Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
662  * AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
663  * AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK, AVFMT_SEEK_TO_PTS.
664  */
665  int flags;
667  /**
668  * If extensions are defined, then no probe is done. You should
669  * usually not use extension format guessing because it is not
670  * reliable enough
671  */
672  const char *extensions;
674  const struct AVCodecTag * const *codec_tag;
675 
676  const AVClass *priv_class; ///< AVClass for the private context
677 
678  /**
679  * Comma-separated list of mime types.
680  * It is used check for matching mime types while probing.
681  * @see av_probe_input_format2
682  */
683  const char *mime_type;
685  /*****************************************************************
686  * No fields below this line are part of the public API. They
687  * may not be used outside of libavformat and can be changed and
688  * removed at will.
689  * New public fields should be added right above.
690  *****************************************************************
691  */
692  struct AVInputFormat *next;
693 
694  /**
695  * Raw demuxers store their codec ID here.
696  */
697  int raw_codec_id;
698 
699  /**
700  * Size of private data so that it can be allocated in the wrapper.
701  */
702  int priv_data_size;
703 
704  /**
705  * Tell if a given file has a chance of being parsed as this format.
706  * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
707  * big so you do not have to check for that unless you need more.
708  */
709  int (*read_probe)(AVProbeData *);
711  /**
712  * Read the format header and initialize the AVFormatContext
713  * structure. Return 0 if OK. 'avformat_new_stream' should be
714  * called to create new streams.
715  */
716  int (*read_header)(struct AVFormatContext *);
718  /**
719  * Read one packet and put it in 'pkt'. pts and flags are also
720  * set. 'avformat_new_stream' can be called only if the flag
721  * AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
722  * background thread).
723  * @return 0 on success, < 0 on error.
724  * When returning an error, pkt must not have been allocated
725  * or must be freed before returning
726  */
727  int (*read_packet)(struct AVFormatContext *, AVPacket *pkt);
728 
729  /**
730  * Close the stream. The AVFormatContext and AVStreams are not
731  * freed by this function
732  */
733  int (*read_close)(struct AVFormatContext *);
734 
735  /**
736  * Seek to a given timestamp relative to the frames in
737  * stream component stream_index.
738  * @param stream_index Must not be -1.
739  * @param flags Selects which direction should be preferred if no exact
740  * match is available.
741  * @return >= 0 on success (but not necessarily the new offset)
742  */
743  int (*read_seek)(struct AVFormatContext *,
744  int stream_index, int64_t timestamp, int flags);
745 
746  /**
747  * Get the next timestamp in stream[stream_index].time_base units.
748  * @return the timestamp or AV_NOPTS_VALUE if an error occurred
749  */
750  int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index,
751  int64_t *pos, int64_t pos_limit);
752 
753  /**
754  * Start/resume playing - only meaningful if using a network-based format
755  * (RTSP).
756  */
757  int (*read_play)(struct AVFormatContext *);
759  /**
760  * Pause playing - only meaningful if using a network-based format
761  * (RTSP).
762  */
763  int (*read_pause)(struct AVFormatContext *);
764 
765  /**
766  * Seek to timestamp ts.
767  * Seeking will be done so that the point from which all active streams
768  * can be presented successfully will be closest to ts and within min/max_ts.
769  * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
770  */
771  int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
772 
773  /**
774  * Returns device list with it properties.
775  * @see avdevice_list_devices() for more details.
776  */
777  int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list);
778 
779  /**
780  * Initialize device capabilities submodule.
781  * @see avdevice_capabilities_create() for more details.
782  */
783  int (*create_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);
784 
785  /**
786  * Free device capabilities submodule.
787  * @see avdevice_capabilities_free() for more details.
788  */
789  int (*free_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);
790 } AVInputFormat;
791 /**
792  * @}
793  */
794 
795 enum AVStreamParseType {
797  AVSTREAM_PARSE_FULL, /**< full parsing and repack */
798  AVSTREAM_PARSE_HEADERS, /**< Only parse headers, do not repack. */
799  AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */
800  AVSTREAM_PARSE_FULL_ONCE, /**< full parsing and repack of the first frame only, only implemented for H.264 currently */
801  AVSTREAM_PARSE_FULL_RAW=MKTAG(0,'R','A','W'), /**< full parsing and repack with timestamp and position generation by parser for raw
802  this assumes that each packet in the file contains no demuxer level headers and
803  just codec level data, otherwise position generation would fail */
804 };
806 typedef struct AVIndexEntry {
807  int64_t pos;
808  int64_t timestamp; /**<
809  * Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are available
810  * when seeking to this entry. That means preferable PTS on keyframe based formats.
811  * But demuxers can choose to store a different timestamp, if it is more convenient for the implementation or nothing better
812  * is known
813  */
814 #define AVINDEX_KEYFRAME 0x0001
815  int flags:2;
816  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).
817  int min_distance; /**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */
818 } AVIndexEntry;
819 
820 #define AV_DISPOSITION_DEFAULT 0x0001
821 #define AV_DISPOSITION_DUB 0x0002
822 #define AV_DISPOSITION_ORIGINAL 0x0004
823 #define AV_DISPOSITION_COMMENT 0x0008
824 #define AV_DISPOSITION_LYRICS 0x0010
825 #define AV_DISPOSITION_KARAOKE 0x0020
826 
827 /**
828  * Track should be used during playback by default.
829  * Useful for subtitle track that should be displayed
830  * even when user did not explicitly ask for subtitles.
831  */
832 #define AV_DISPOSITION_FORCED 0x0040
833 #define AV_DISPOSITION_HEARING_IMPAIRED 0x0080 /**< stream for hearing impaired audiences */
834 #define AV_DISPOSITION_VISUAL_IMPAIRED 0x0100 /**< stream for visual impaired audiences */
835 #define AV_DISPOSITION_CLEAN_EFFECTS 0x0200 /**< stream without voice */
836 /**
837  * The stream is stored in the file as an attached picture/"cover art" (e.g.
838  * APIC frame in ID3v2). The single packet associated with it will be returned
839  * among the first few packets read from the file unless seeking takes place.
840  * It can also be accessed at any time in AVStream.attached_pic.
841  */
842 #define AV_DISPOSITION_ATTACHED_PIC 0x0400
844 /**
845  * To specify text track kind (different from subtitles default).
846  */
847 #define AV_DISPOSITION_CAPTIONS 0x10000
848 #define AV_DISPOSITION_DESCRIPTIONS 0x20000
849 #define AV_DISPOSITION_METADATA 0x40000
851 /**
852  * Options for behavior on timestamp wrap detection.
853  */
854 #define AV_PTS_WRAP_IGNORE 0 ///< ignore the wrap
855 #define AV_PTS_WRAP_ADD_OFFSET 1 ///< add the format specific offset on wrap detection
856 #define AV_PTS_WRAP_SUB_OFFSET -1 ///< subtract the format specific offset on wrap detection
858 /**
859  * Stream structure.
860  * New fields can be added to the end with minor version bumps.
861  * Removal, reordering and changes to existing fields require a major
862  * version bump.
863  * sizeof(AVStream) must not be used outside libav*.
864  */
865 typedef struct AVStream {
866  int index; /**< stream index in AVFormatContext */
867  /**
868  * Format-specific stream ID.
869  * decoding: set by libavformat
870  * encoding: set by the user, replaced by libavformat if left unset
871  */
872  int id;
873  /**
874  * Codec context associated with this stream. Allocated and freed by
875  * libavformat.
876  *
877  * - decoding: The demuxer exports codec information stored in the headers
878  * here.
879  * - encoding: The user sets codec information, the muxer writes it to the
880  * output. Mandatory fields as specified in AVCodecContext
881  * documentation must be set even if this AVCodecContext is
882  * not actually used for encoding.
883  */
884  AVCodecContext *codec;
885  void *priv_data;
886 
887 #if FF_API_LAVF_FRAC
888  /**
889  * @deprecated this field is unused
890  */
892  struct AVFrac pts;
893 #endif
894 
895  /**
896  * This is the fundamental unit of time (in seconds) in terms
897  * of which frame timestamps are represented.
898  *
899  * decoding: set by libavformat
900  * encoding: May be set by the caller before avformat_write_header() to
901  * provide a hint to the muxer about the desired timebase. In
902  * avformat_write_header(), the muxer will overwrite this field
903  * with the timebase that will actually be used for the timestamps
904  * written into the file (which may or may not be related to the
905  * user-provided one, depending on the format).
906  */
907  AVRational time_base;
908 
909  /**
910  * Decoding: pts of the first frame of the stream in presentation order, in stream time base.
911  * Only set this if you are absolutely 100% sure that the value you set
912  * it to really is the pts of the first frame.
913  * This may be undefined (AV_NOPTS_VALUE).
914  * @note The ASF header does NOT contain a correct start_time the ASF
915  * demuxer must NOT set this.
916  */
917  int64_t start_time;
918 
919  /**
920  * Decoding: duration of the stream, in stream time base.
921  * If a source file does not specify a duration, but does specify
922  * a bitrate, this value will be estimated from bitrate and file size.
923  */
924  int64_t duration;
926  int64_t nb_frames; ///< number of frames in this stream if known or 0
927 
928  int disposition; /**< AV_DISPOSITION_* bit field */
929 
930  enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
931 
932  /**
933  * sample aspect ratio (0 if unknown)
934  * - encoding: Set by user.
935  * - decoding: Set by libavformat.
936  */
937  AVRational sample_aspect_ratio;
939  AVDictionary *metadata;
940 
941  /**
942  * Average framerate
943  *
944  * - demuxing: May be set by libavformat when creating the stream or in
945  * avformat_find_stream_info().
946  * - muxing: May be set by the caller before avformat_write_header().
947  */
948  AVRational avg_frame_rate;
949 
950  /**
951  * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
952  * will contain the attached picture.
953  *
954  * decoding: set by libavformat, must not be modified by the caller.
955  * encoding: unused
956  */
957  AVPacket attached_pic;
958 
959  /**
960  * An array of side data that applies to the whole stream (i.e. the
961  * container does not allow it to change between packets).
962  *
963  * There may be no overlap between the side data in this array and side data
964  * in the packets. I.e. a given side data is either exported by the muxer
965  * (demuxing) / set by the caller (muxing) in this array, then it never
966  * appears in the packets, or the side data is exported / sent through
967  * the packets (always in the first packet where the value becomes known or
968  * changes), then it does not appear in this array.
969  *
970  * - demuxing: Set by libavformat when the stream is created.
971  * - muxing: May be set by the caller before avformat_write_header().
972  *
973  * Freed by libavformat in avformat_free_context().
974  *
975  * @see av_format_inject_global_side_data()
976  */
977  AVPacketSideData *side_data;
978  /**
979  * The number of elements in the AVStream.side_data array.
980  */
981  int nb_side_data;
982 
983  /**
984  * Flags for the user to detect events happening on the stream. Flags must
985  * be cleared by the user once the event has been handled.
986  * A combination of AVSTREAM_EVENT_FLAG_*.
987  */
988  int event_flags;
989 #define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
990 
991  /*****************************************************************
992  * All fields below this line are not part of the public API. They
993  * may not be used outside of libavformat and can be changed and
994  * removed at will.
995  * New public fields should be added right above.
996  *****************************************************************
997  */
998 
999  /**
1000  * Stream information used internally by av_find_stream_info()
1001  */
1002 #define MAX_STD_TIMEBASES (30*12+30+3+6)
1003  struct {
1004  int64_t last_dts;
1005  int64_t duration_gcd;
1006  int duration_count;
1007  int64_t rfps_duration_sum;
1008  double (*duration_error)[2][MAX_STD_TIMEBASES];
1009  int64_t codec_info_duration;
1010  int64_t codec_info_duration_fields;
1011 
1012  /**
1013  * 0 -> decoder has not been searched for yet.
1014  * >0 -> decoder found
1015  * <0 -> decoder with codec_id == -found_decoder has not been found
1016  */
1017  int found_decoder;
1019  int64_t last_duration;
1020 
1021  /**
1022  * Those are used for average framerate estimation.
1023  */
1024  int64_t fps_first_dts;
1025  int fps_first_dts_idx;
1026  int64_t fps_last_dts;
1027  int fps_last_dts_idx;
1028 
1029  } *info;
1030 
1031  int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
1033  // Timestamp generation support:
1034  /**
1035  * Timestamp corresponding to the last dts sync point.
1036  *
1037  * Initialized when AVCodecParserContext.dts_sync_point >= 0 and
1038  * a DTS is received from the underlying container. Otherwise set to
1039  * AV_NOPTS_VALUE by default.
1040  */
1041  int64_t first_dts;
1042  int64_t cur_dts;
1043  int64_t last_IP_pts;
1044  int last_IP_duration;
1045 
1046  /**
1047  * Number of packets to buffer for codec probing
1048  */
1049  int probe_packets;
1051  /**
1052  * Number of frames that have been demuxed during av_find_stream_info()
1053  */
1054  int codec_info_nb_frames;
1055 
1056  /* av_read_frame() support */
1057  enum AVStreamParseType need_parsing;
1058  struct AVCodecParserContext *parser;
1059 
1060  /**
1061  * last packet in packet_buffer for this stream when muxing.
1062  */
1063  struct AVPacketList *last_in_packet_buffer;
1064  AVProbeData probe_data;
1065 #define MAX_REORDER_DELAY 16
1066  int64_t pts_buffer[MAX_REORDER_DELAY+1];
1067 
1068  AVIndexEntry *index_entries; /**< Only used if the format does not
1069  support seeking natively. */
1070  int nb_index_entries;
1071  unsigned int index_entries_allocated_size;
1073  /**
1074  * Real base framerate of the stream.
1075  * This is the lowest framerate with which all timestamps can be
1076  * represented accurately (it is the least common multiple of all
1077  * framerates in the stream). Note, this value is just a guess!
1078  * For example, if the time base is 1/90000 and all frames have either
1079  * approximately 3600 or 1800 timer ticks, then r_frame_rate will be 50/1.
1080  *
1081  * Code outside avformat should access this field using:
1082  * av_stream_get/set_r_frame_rate(stream)
1083  */
1084  AVRational r_frame_rate;
1085 
1086  /**
1087  * Stream Identifier
1088  * This is the MPEG-TS stream identifier +1
1089  * 0 means unknown
1090  */
1091  int stream_identifier;
1093  int64_t interleaver_chunk_size;
1094  int64_t interleaver_chunk_duration;
1095 
1096  /**
1097  * stream probing state
1098  * -1 -> probing finished
1099  * 0 -> no probing requested
1100  * rest -> perform probing with request_probe being the minimum score to accept.
1101  * NOT PART OF PUBLIC API
1102  */
1103  int request_probe;
1104  /**
1105  * Indicates that everything up to the next keyframe
1106  * should be discarded.
1107  */
1108  int skip_to_keyframe;
1109 
1110  /**
1111  * Number of samples to skip at the start of the frame decoded from the next packet.
1112  */
1113  int skip_samples;
1114 
1115  /**
1116  * If not 0, the number of samples that should be skipped from the start of
1117  * the stream (the samples are removed from packets with pts==0, which also
1118  * assumes negative timestamps do not happen).
1119  * Intended for use with formats such as mp3 with ad-hoc gapless audio
1120  * support.
1121  */
1122  int64_t start_skip_samples;
1123 
1124  /**
1125  * If not 0, the first audio sample that should be discarded from the stream.
1126  * This is broken by design (needs global sample count), but can't be
1127  * avoided for broken by design formats such as mp3 with ad-hoc gapless
1128  * audio support.
1129  */
1130  int64_t first_discard_sample;
1131 
1132  /**
1133  * The sample after last sample that is intended to be discarded after
1134  * first_discard_sample. Works on frame boundaries only. Used to prevent
1135  * early EOF if the gapless info is broken (considered concatenated mp3s).
1136  */
1137  int64_t last_discard_sample;
1139  /**
1140  * Number of internally decoded frames, used internally in libavformat, do not access
1141  * its lifetime differs from info which is why it is not in that structure.
1142  */
1143  int nb_decoded_frames;
1144 
1145  /**
1146  * Timestamp offset added to timestamps before muxing
1147  * NOT PART OF PUBLIC API
1148  */
1149  int64_t mux_ts_offset;
1150 
1151  /**
1152  * Internal data to check for wrapping of the time stamp
1153  */
1154  int64_t pts_wrap_reference;
1155 
1156  /**
1157  * Options for behavior, when a wrap is detected.
1158  *
1159  * Defined by AV_PTS_WRAP_ values.
1160  *
1161  * If correction is enabled, there are two possibilities:
1162  * If the first time stamp is near the wrap point, the wrap offset
1163  * will be subtracted, which will create negative time stamps.
1164  * Otherwise the offset will be added.
1165  */
1166  int pts_wrap_behavior;
1167 
1168  /**
1169  * Internal data to prevent doing update_initial_durations() twice
1170  */
1171  int update_initial_durations_done;
1172 
1173  /**
1174  * Internal data to generate dts from pts
1175  */
1176  int64_t pts_reorder_error[MAX_REORDER_DELAY+1];
1177  uint8_t pts_reorder_error_count[MAX_REORDER_DELAY+1];
1178 
1179  /**
1180  * Internal data to analyze DTS and detect faulty mpeg streams
1181  */
1182  int64_t last_dts_for_order_check;
1183  uint8_t dts_ordered;
1184  uint8_t dts_misordered;
1186  /**
1187  * Internal data to inject global side data
1188  */
1189  int inject_global_side_data;
1191  /**
1192  * String containing paris of key and values describing recommended encoder configuration.
1193  * Paris are separated by ','.
1194  * Keys are separated from values by '='.
1195  */
1196  char *recommended_encoder_configuration;
1198  /**
1199  * display aspect ratio (0 if unknown)
1200  * - encoding: unused
1201  * - decoding: Set by libavformat to calculate sample_aspect_ratio internally
1202  */
1203  AVRational display_aspect_ratio;
1205  struct FFFrac *priv_pts;
1206 } AVStream;
1207 
1212 void av_stream_set_recommended_encoder_configuration(AVStream *s, char *configuration);
1214 /**
1215  * Returns the pts of the last muxed packet + its duration
1216  *
1217  * the retuned value is undefined when used with a demuxer.
1218  */
1219 int64_t av_stream_get_end_pts(const AVStream *st);
1220 
1221 #define AV_PROGRAM_RUNNING 1
1222 
1223 /**
1224  * New fields can be added to the end with minor version bumps.
1225  * Removal, reordering and changes to existing fields require a major
1226  * version bump.
1227  * sizeof(AVProgram) must not be used outside libav*.
1228  */
1229 typedef struct AVProgram {
1230  int id;
1231  int flags;
1232  enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
1233  unsigned int *stream_index;
1234  unsigned int nb_stream_indexes;
1235  AVDictionary *metadata;
1236 
1237  int program_num;
1238  int pmt_pid;
1239  int pcr_pid;
1241  /*****************************************************************
1242  * All fields below this line are not part of the public API. They
1243  * may not be used outside of libavformat and can be changed and
1244  * removed at will.
1245  * New public fields should be added right above.
1246  *****************************************************************
1247  */
1248  int64_t start_time;
1249  int64_t end_time;
1250 
1251  int64_t pts_wrap_reference; ///< reference dts for wrap detection
1252  int pts_wrap_behavior; ///< behavior on wrap detection
1253 } AVProgram;
1254 
1255 #define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
1256  (streams are added dynamically) */
1258 typedef struct AVChapter {
1259  int id; ///< unique ID to identify the chapter
1260  AVRational time_base; ///< time base in which the start/end timestamps are specified
1261  int64_t start, end; ///< chapter start/end time in time_base units
1262  AVDictionary *metadata;
1264 
1265 
1266 /**
1267  * Callback used by devices to communicate with application.
1268  */
1269 typedef int (*av_format_control_message)(struct AVFormatContext *s, int type,
1270  void *data, size_t data_size);
1272 typedef int (*AVOpenCallback)(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags,
1273  const AVIOInterruptCB *int_cb, AVDictionary **options);
1274 
1275 /**
1276  * The duration of a video can be estimated through various ways, and this enum can be used
1277  * to know how the duration was estimated.
1278  */
1280  AVFMT_DURATION_FROM_PTS, ///< Duration accurately estimated from PTSes
1281  AVFMT_DURATION_FROM_STREAM, ///< Duration estimated from a stream with a known duration
1282  AVFMT_DURATION_FROM_BITRATE ///< Duration estimated from bitrate (less accurate)
1283 };
1284 
1285 typedef struct AVFormatInternal AVFormatInternal;
1286 
1287 /**
1288  * Format I/O context.
1289  * New fields can be added to the end with minor version bumps.
1290  * Removal, reordering and changes to existing fields require a major
1291  * version bump.
1292  * sizeof(AVFormatContext) must not be used outside libav*, use
1293  * avformat_alloc_context() to create an AVFormatContext.
1294  */
1295 typedef struct AVFormatContext {
1296  /**
1297  * A class for logging and @ref avoptions. Set by avformat_alloc_context().
1298  * Exports (de)muxer private options if they exist.
1299  */
1300  const AVClass *av_class;
1301 
1302  /**
1303  * The input container format.
1304  *
1305  * Demuxing only, set by avformat_open_input().
1306  */
1307  struct AVInputFormat *iformat;
1308 
1309  /**
1310  * The output container format.
1311  *
1312  * Muxing only, must be set by the caller before avformat_write_header().
1313  */
1314  struct AVOutputFormat *oformat;
1315 
1316  /**
1317  * Format private data. This is an AVOptions-enabled struct
1318  * if and only if iformat/oformat.priv_class is not NULL.
1319  *
1320  * - muxing: set by avformat_write_header()
1321  * - demuxing: set by avformat_open_input()
1322  */
1323  void *priv_data;
1324 
1325  /**
1326  * I/O context.
1327  *
1328  * - demuxing: either set by the user before avformat_open_input() (then
1329  * the user must close it manually) or set by avformat_open_input().
1330  * - muxing: set by the user before avformat_write_header(). The caller must
1331  * take care of closing / freeing the IO context.
1332  *
1333  * Do NOT set this field if AVFMT_NOFILE flag is set in
1334  * iformat/oformat.flags. In such a case, the (de)muxer will handle
1335  * I/O in some other way and this field will be NULL.
1336  */
1337  AVIOContext *pb;
1338 
1339  /* stream info */
1340  /**
1341  * Flags signalling stream properties. A combination of AVFMTCTX_*.
1342  * Set by libavformat.
1343  */
1344  int ctx_flags;
1345 
1346  /**
1347  * Number of elements in AVFormatContext.streams.
1348  *
1349  * Set by avformat_new_stream(), must not be modified by any other code.
1350  */
1351  unsigned int nb_streams;
1352  /**
1353  * A list of all streams in the file. New streams are created with
1354  * avformat_new_stream().
1355  *
1356  * - demuxing: streams are created by libavformat in avformat_open_input().
1357  * If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
1358  * appear in av_read_frame().
1359  * - muxing: streams are created by the user before avformat_write_header().
1360  *
1361  * Freed by libavformat in avformat_free_context().
1362  */
1363  AVStream **streams;
1364 
1365  /**
1366  * input or output filename
1367  *
1368  * - demuxing: set by avformat_open_input()
1369  * - muxing: may be set by the caller before avformat_write_header()
1370  */
1371  char filename[1024];
1373  /**
1374  * Position of the first frame of the component, in
1375  * AV_TIME_BASE fractional seconds. NEVER set this value directly:
1376  * It is deduced from the AVStream values.
1377  *
1378  * Demuxing only, set by libavformat.
1379  */
1380  int64_t start_time;
1381 
1382  /**
1383  * Duration of the stream, in AV_TIME_BASE fractional
1384  * seconds. Only set this value if you know none of the individual stream
1385  * durations and also do not set any of them. This is deduced from the
1386  * AVStream values if not set.
1387  *
1388  * Demuxing only, set by libavformat.
1389  */
1390  int64_t duration;
1391 
1392  /**
1393  * Total stream bitrate in bit/s, 0 if not
1394  * available. Never set it directly if the file_size and the
1395  * duration are known as FFmpeg can compute it automatically.
1396  */
1397  int bit_rate;
1398 
1399  unsigned int packet_size;
1400  int max_delay;
1401 
1402  /**
1403  * Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
1404  * Set by the user before avformat_open_input() / avformat_write_header().
1405  */
1406  int flags;
1407 #define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
1408 #define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
1409 #define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
1410 #define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
1411 #define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container
1412 #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
1413 #define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
1414 #define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
1415 #define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
1416 #define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
1417 /**
1418  * When muxing, try to avoid writing any random/volatile data to the output.
1419  * This includes any random IDs, real-time timestamps/dates, muxer version, etc.
1420  *
1421  * This flag is mainly intended for testing.
1422  */
1423 #define AVFMT_FLAG_BITEXACT 0x0400
1424 #define AVFMT_FLAG_MP4A_LATM 0x8000 ///< Enable RTP MP4A-LATM payload
1425 #define AVFMT_FLAG_SORT_DTS 0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
1426 #define AVFMT_FLAG_PRIV_OPT 0x20000 ///< Enable use of private options by delaying codec open (this could be made default once all code is converted)
1427 #define AVFMT_FLAG_KEEP_SIDE_DATA 0x40000 ///< Don't merge side data but keep it separate.
1428 #define AVFMT_FLAG_FAST_SEEK 0x80000 ///< Enable fast, but inaccurate seeks for some formats
1429 
1430 #if FF_API_PROBESIZE_32
1431  /**
1432  * @deprecated deprecated in favor of probesize2
1433  */
1434  unsigned int probesize;
1436  /**
1437  * @deprecated deprecated in favor of max_analyze_duration2
1438  */
1440  int max_analyze_duration;
1441 #endif
1442 
1443  const uint8_t *key;
1444  int keylen;
1445 
1446  unsigned int nb_programs;
1447  AVProgram **programs;
1448 
1449  /**
1450  * Forced video codec_id.
1451  * Demuxing: Set by user.
1452  */
1453  enum AVCodecID video_codec_id;
1454 
1455  /**
1456  * Forced audio codec_id.
1457  * Demuxing: Set by user.
1458  */
1459  enum AVCodecID audio_codec_id;
1460 
1461  /**
1462  * Forced subtitle codec_id.
1463  * Demuxing: Set by user.
1464  */
1465  enum AVCodecID subtitle_codec_id;
1466 
1467  /**
1468  * Maximum amount of memory in bytes to use for the index of each stream.
1469  * If the index exceeds this size, entries will be discarded as
1470  * needed to maintain a smaller size. This can lead to slower or less
1471  * accurate seeking (depends on demuxer).
1472  * Demuxers for which a full in-memory index is mandatory will ignore
1473  * this.
1474  * - muxing: unused
1475  * - demuxing: set by user
1476  */
1477  unsigned int max_index_size;
1478 
1479  /**
1480  * Maximum amount of memory in bytes to use for buffering frames
1481  * obtained from realtime capture devices.
1482  */
1483  unsigned int max_picture_buffer;
1484 
1485  /**
1486  * Number of chapters in AVChapter array.
1487  * When muxing, chapters are normally written in the file header,
1488  * so nb_chapters should normally be initialized before write_header
1489  * is called. Some muxers (e.g. mov and mkv) can also write chapters
1490  * in the trailer. To write chapters in the trailer, nb_chapters
1491  * must be zero when write_header is called and non-zero when
1492  * write_trailer is called.
1493  * - muxing: set by user
1494  * - demuxing: set by libavformat
1495  */
1496  unsigned int nb_chapters;
1497  AVChapter **chapters;
1498 
1499  /**
1500  * Metadata that applies to the whole file.
1501  *
1502  * - demuxing: set by libavformat in avformat_open_input()
1503  * - muxing: may be set by the caller before avformat_write_header()
1504  *
1505  * Freed by libavformat in avformat_free_context().
1506  */
1507  AVDictionary *metadata;
1508 
1509  /**
1510  * Start time of the stream in real world time, in microseconds
1511  * since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1512  * stream was captured at this real world time.
1513  * - muxing: Set by the caller before avformat_write_header(). If set to
1514  * either 0 or AV_NOPTS_VALUE, then the current wall-time will
1515  * be used.
1516  * - demuxing: Set by libavformat. AV_NOPTS_VALUE if unknown. Note that
1517  * the value may become known after some number of frames
1518  * have been received.
1519  */
1520  int64_t start_time_realtime;
1521 
1522  /**
1523  * The number of frames used for determining the framerate in
1524  * avformat_find_stream_info().
1525  * Demuxing only, set by the caller before avformat_find_stream_info().
1526  */
1527  int fps_probe_size;
1528 
1529  /**
1530  * Error recognition; higher values will detect more errors but may
1531  * misdetect some more or less valid parts as errors.
1532  * Demuxing only, set by the caller before avformat_open_input().
1533  */
1534  int error_recognition;
1535 
1536  /**
1537  * Custom interrupt callbacks for the I/O layer.
1538  *
1539  * demuxing: set by the user before avformat_open_input().
1540  * muxing: set by the user before avformat_write_header()
1541  * (mainly useful for AVFMT_NOFILE formats). The callback
1542  * should also be passed to avio_open2() if it's used to
1543  * open the file.
1544  */
1545  AVIOInterruptCB interrupt_callback;
1546 
1547  /**
1548  * Flags to enable debugging.
1549  */
1550  int debug;
1551 #define FF_FDEBUG_TS 0x0001
1552 
1553  /**
1554  * Maximum buffering duration for interleaving.
1555  *
1556  * To ensure all the streams are interleaved correctly,
1557  * av_interleaved_write_frame() will wait until it has at least one packet
1558  * for each stream before actually writing any packets to the output file.
1559  * When some streams are "sparse" (i.e. there are large gaps between
1560  * successive packets), this can result in excessive buffering.
1561  *
1562  * This field specifies the maximum difference between the timestamps of the
1563  * first and the last packet in the muxing queue, above which libavformat
1564  * will output a packet regardless of whether it has queued a packet for all
1565  * the streams.
1566  *
1567  * Muxing only, set by the caller before avformat_write_header().
1568  */
1569  int64_t max_interleave_delta;
1570 
1571  /**
1572  * Allow non-standard and experimental extension
1573  * @see AVCodecContext.strict_std_compliance
1574  */
1575  int strict_std_compliance;
1576 
1577  /**
1578  * Flags for the user to detect events happening on the file. Flags must
1579  * be cleared by the user once the event has been handled.
1580  * A combination of AVFMT_EVENT_FLAG_*.
1581  */
1582  int event_flags;
1583 #define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
1585  /**
1586  * Maximum number of packets to read while waiting for the first timestamp.
1587  * Decoding only.
1588  */
1589  int max_ts_probe;
1590 
1591  /**
1592  * Avoid negative timestamps during muxing.
1593  * Any value of the AVFMT_AVOID_NEG_TS_* constants.
1594  * Note, this only works when using av_interleaved_write_frame. (interleave_packet_per_dts is in use)
1595  * - muxing: Set by user
1596  * - demuxing: unused
1597  */
1598  int avoid_negative_ts;
1599 #define AVFMT_AVOID_NEG_TS_AUTO -1 ///< Enabled when required by target format
1600 #define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
1601 #define AVFMT_AVOID_NEG_TS_MAKE_ZERO 2 ///< Shift timestamps so that they start at 0
1602 
1603  /**
1604  * Transport stream id.
1605  * This will be moved into demuxer private options. Thus no API/ABI compatibility
1606  */
1607  int ts_id;
1609  /**
1610  * Audio preload in microseconds.
1611  * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1612  * - encoding: Set by user via AVOptions (NO direct access)
1613  * - decoding: unused
1614  */
1615  int audio_preload;
1617  /**
1618  * Max chunk time in microseconds.
1619  * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1620  * - encoding: Set by user via AVOptions (NO direct access)
1621  * - decoding: unused
1622  */
1623  int max_chunk_duration;
1625  /**
1626  * Max chunk size in bytes
1627  * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1628  * - encoding: Set by user via AVOptions (NO direct access)
1629  * - decoding: unused
1630  */
1631  int max_chunk_size;
1633  /**
1634  * forces the use of wallclock timestamps as pts/dts of packets
1635  * This has undefined results in the presence of B frames.
1636  * - encoding: unused
1637  * - decoding: Set by user via AVOptions (NO direct access)
1638  */
1639  int use_wallclock_as_timestamps;
1641  /**
1642  * avio flags, used to force AVIO_FLAG_DIRECT.
1643  * - encoding: unused
1644  * - decoding: Set by user via AVOptions (NO direct access)
1645  */
1646  int avio_flags;
1647 
1648  /**
1649  * The duration field can be estimated through various ways, and this field can be used
1650  * to know how the duration was estimated.
1651  * - encoding: unused
1652  * - decoding: Read by user via AVOptions (NO direct access)
1653  */
1654  enum AVDurationEstimationMethod duration_estimation_method;
1656  /**
1657  * Skip initial bytes when opening stream
1658  * - encoding: unused
1659  * - decoding: Set by user via AVOptions (NO direct access)
1660  */
1661  int64_t skip_initial_bytes;
1662 
1663  /**
1664  * Correct single timestamp overflows
1665  * - encoding: unused
1666  * - decoding: Set by user via AVOptions (NO direct access)
1667  */
1668  unsigned int correct_ts_overflow;
1669 
1670  /**
1671  * Force seeking to any (also non key) frames.
1672  * - encoding: unused
1673  * - decoding: Set by user via AVOptions (NO direct access)
1674  */
1675  int seek2any;
1676 
1677  /**
1678  * Flush the I/O context after each packet.
1679  * - encoding: Set by user via AVOptions (NO direct access)
1680  * - decoding: unused
1681  */
1682  int flush_packets;
1683 
1684  /**
1685  * format probing score.
1686  * The maximal score is AVPROBE_SCORE_MAX, its set when the demuxer probes
1687  * the format.
1688  * - encoding: unused
1689  * - decoding: set by avformat, read by user via av_format_get_probe_score() (NO direct access)
1690  */
1691  int probe_score;
1692 
1693  /**
1694  * number of bytes to read maximally to identify format.
1695  * - encoding: unused
1696  * - decoding: set by user through AVOPtions (NO direct access)
1697  */
1698  int format_probesize;
1699 
1700  /**
1701  * ',' separated list of allowed decoders.
1702  * If NULL then all are allowed
1703  * - encoding: unused
1704  * - decoding: set by user through AVOptions (NO direct access)
1705  */
1706  char *codec_whitelist;
1708  /**
1709  * ',' separated list of allowed demuxers.
1710  * If NULL then all are allowed
1711  * - encoding: unused
1712  * - decoding: set by user through AVOptions (NO direct access)
1713  */
1714  char *format_whitelist;
1716  /**
1717  * An opaque field for libavformat internal usage.
1718  * Must not be accessed in any way by callers.
1719  */
1720  AVFormatInternal *internal;
1721 
1722  /**
1723  * IO repositioned flag.
1724  * This is set by avformat when the underlaying IO context read pointer
1725  * is repositioned, for example when doing byte based seeking.
1726  * Demuxers can use the flag to detect such changes.
1727  */
1728  int io_repositioned;
1730  /**
1731  * Forced video codec.
1732  * This allows forcing a specific decoder, even when there are multiple with
1733  * the same codec_id.
1734  * Demuxing: Set by user via av_format_set_video_codec (NO direct access).
1735  */
1738  /**
1739  * Forced audio codec.
1740  * This allows forcing a specific decoder, even when there are multiple with
1741  * the same codec_id.
1742  * Demuxing: Set by user via av_format_set_audio_codec (NO direct access).
1743  */
1746  /**
1747  * Forced subtitle codec.
1748  * This allows forcing a specific decoder, even when there are multiple with
1749  * the same codec_id.
1750  * Demuxing: Set by user via av_format_set_subtitle_codec (NO direct access).
1751  */
1754  /**
1755  * Forced data codec.
1756  * This allows forcing a specific decoder, even when there are multiple with
1757  * the same codec_id.
1758  * Demuxing: Set by user via av_format_set_data_codec (NO direct access).
1759  */
1762  /**
1763  * Number of bytes to be written as padding in a metadata header.
1764  * Demuxing: Unused.
1765  * Muxing: Set by user via av_format_set_metadata_header_padding.
1766  */
1767  int metadata_header_padding;
1768 
1769  /**
1770  * User data.
1771  * This is a place for some private data of the user.
1772  * Mostly usable with control_message_cb or any future callbacks in device's context.
1773  */
1774  void *opaque;
1775 
1776  /**
1777  * Callback used by devices to communicate with application.
1778  */
1779  av_format_control_message control_message_cb;
1780 
1781  /**
1782  * Output timestamp offset, in microseconds.
1783  * Muxing: set by user via AVOptions (NO direct access)
1784  */
1785  int64_t output_ts_offset;
1786 
1787  /**
1788  * Maximum duration (in AV_TIME_BASE units) of the data read
1789  * from input in avformat_find_stream_info().
1790  * Demuxing only, set by the caller before avformat_find_stream_info()
1791  * via AVOptions (NO direct access).
1792  * Can be set to 0 to let avformat choose using a heuristic.
1793  */
1794 #if FF_API_PROBESIZE_32
1795  int64_t max_analyze_duration2;
1796 #else
1797  int64_t max_analyze_duration;
1798 #endif
1799 
1800  /**
1801  * Maximum size of the data read from input for determining
1802  * the input container format.
1803  * Demuxing only, set by the caller before avformat_open_input()
1804  * via AVOptions (NO direct access).
1805  */
1806 #if FF_API_PROBESIZE_32
1807  int64_t probesize2;
1808 #else
1809  int64_t probesize;
1810 #endif
1811 
1812  /**
1813  * dump format separator.
1814  * can be ", " or "\n " or anything else
1815  * Code outside libavformat should access this field using AVOptions
1816  * (NO direct access).
1817  * - muxing: Set by user.
1818  * - demuxing: Set by user.
1819  */
1820  uint8_t *dump_separator;
1821 
1822  /**
1823  * Forced Data codec_id.
1824  * Demuxing: Set by user.
1825  */
1826  enum AVCodecID data_codec_id;
1827 
1828  /**
1829  * Called to open further IO contexts when needed for demuxing.
1830  *
1831  * This can be set by the user application to perform security checks on
1832  * the URLs before opening them.
1833  * The function should behave like avio_open2(), AVFormatContext is provided
1834  * as contextual information and to reach AVFormatContext.opaque.
1835  *
1836  * If NULL then some simple checks are used together with avio_open2().
1837  *
1838  * Must not be accessed directly from outside avformat.
1839  * @See av_format_set_open_cb()
1840  *
1841  * Demuxing: Set by user.
1842  */
1843  int (*open_cb)(struct AVFormatContext *s, AVIOContext **p, const char *url, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options);
1844 
1845  /**
1846  * The maximum number of streams.
1847  * - encoding: unused
1848  * - decoding: set by user through AVOptions (NO direct access)
1849  */
1850  int max_streams;
1851 } AVFormatContext;
1864 void * av_format_get_opaque(const AVFormatContext *s);
1870 
1871 /**
1872  * This function will cause global side data to be injected in the next packet
1873  * of each stream as well as after any subsequent seek.
1874  */
1876 
1877 /**
1878  * Returns the method used to set ctx->duration.
1879  *
1880  * @return AVFMT_DURATION_FROM_PTS, AVFMT_DURATION_FROM_STREAM, or AVFMT_DURATION_FROM_BITRATE.
1881  */
1883 
1884 typedef struct AVPacketList {
1885  AVPacket pkt;
1886  struct AVPacketList *next;
1887 } AVPacketList;
1888 
1889 
1890 /**
1891  * @defgroup lavf_core Core functions
1892  * @ingroup libavf
1893  *
1894  * Functions for querying libavformat capabilities, allocating core structures,
1895  * etc.
1896  * @{
1897  */
1898 
1899 /**
1900  * Return the LIBAVFORMAT_VERSION_INT constant.
1901  */
1902 unsigned avformat_version(void);
1903 
1904 /**
1905  * Return the libavformat build-time configuration.
1906  */
1907 const char *avformat_configuration(void);
1908 
1909 /**
1910  * Return the libavformat license.
1911  */
1912 const char *avformat_license(void);
1913 
1914 /**
1915  * Initialize libavformat and register all the muxers, demuxers and
1916  * protocols. If you do not call this function, then you can select
1917  * exactly which formats you want to support.
1918  *
1919  * @see av_register_input_format()
1920  * @see av_register_output_format()
1921  */
1922 void av_register_all(void);
1923 
1926 
1927 /**
1928  * Do global initialization of network components. This is optional,
1929  * but recommended, since it avoids the overhead of implicitly
1930  * doing the setup for each session.
1931  *
1932  * Calling this function will become mandatory if using network
1933  * protocols at some major version bump.
1934  */
1935 int avformat_network_init(void);
1936 
1937 /**
1938  * Undo the initialization done by avformat_network_init.
1939  */
1940 int avformat_network_deinit(void);
1941 
1942 /**
1943  * If f is NULL, returns the first registered input format,
1944  * if f is non-NULL, returns the next registered input format after f
1945  * or NULL if f is the last one.
1946  */
1948 
1949 /**
1950  * If f is NULL, returns the first registered output format,
1951  * if f is non-NULL, returns the next registered output format after f
1952  * or NULL if f is the last one.
1953  */
1955 
1956 /**
1957  * Allocate an AVFormatContext.
1958  * avformat_free_context() can be used to free the context and everything
1959  * allocated by the framework within it.
1960  */
1962 
1963 /**
1964  * Free an AVFormatContext and all its streams.
1965  * @param s context to free
1966  */
1968 
1969 /**
1970  * Get the AVClass for AVFormatContext. It can be used in combination with
1971  * AV_OPT_SEARCH_FAKE_OBJ for examining options.
1972  *
1973  * @see av_opt_find().
1974  */
1975 const AVClass *avformat_get_class(void);
1976 
1977 /**
1978  * Add a new stream to a media file.
1979  *
1980  * When demuxing, it is called by the demuxer in read_header(). If the
1981  * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
1982  * be called in read_packet().
1983  *
1984  * When muxing, should be called by the user before avformat_write_header().
1985  *
1986  * User is required to call avcodec_close() and avformat_free_context() to
1987  * clean up the allocation by avformat_new_stream().
1988  *
1989  * @param s media file handle
1990  * @param c If non-NULL, the AVCodecContext corresponding to the new stream
1991  * will be initialized to use this codec. This is needed for e.g. codec-specific
1992  * defaults to be set, so codec should be provided if it is known.
1993  *
1994  * @return newly created stream or NULL on error.
1995  */
1997 
1998 /**
1999  * Get side information from stream.
2000  *
2001  * @param stream stream
2002  * @param type desired side information type
2003  * @param size pointer for side information size to store (optional)
2004  * @return pointer to data if present or NULL otherwise
2005  */
2006 uint8_t *av_stream_get_side_data(AVStream *stream,
2007  enum AVPacketSideDataType type, int *size);
2008 
2010 
2011 /**
2012  * @}
2013  */
2014 
2015 
2016 /**
2017  * Allocate an AVFormatContext for an output format.
2018  * avformat_free_context() can be used to free the context and
2019  * everything allocated by the framework within it.
2020  *
2021  * @param *ctx is set to the created format context, or to NULL in
2022  * case of failure
2023  * @param oformat format to use for allocating the context, if NULL
2024  * format_name and filename are used instead
2025  * @param format_name the name of output format to use for allocating the
2026  * context, if NULL filename is used instead
2027  * @param filename the name of the filename to use for allocating the
2028  * context, may be NULL
2029  * @return >= 0 in case of success, a negative AVERROR code in case of
2030  * failure
2031  */
2033  const char *format_name, const char *filename);
2034 
2035 /**
2036  * @addtogroup lavf_decoding
2037  * @{
2038  */
2039 
2040 /**
2041  * Find AVInputFormat based on the short name of the input format.
2042  */
2043 AVInputFormat *av_find_input_format(const char *short_name);
2044 
2045 /**
2046  * Guess the file format.
2047  *
2048  * @param pd data to be probed
2049  * @param is_opened Whether the file is already opened; determines whether
2050  * demuxers with or without AVFMT_NOFILE are probed.
2051  */
2052 AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened);
2053 
2054 /**
2055  * Guess the file format.
2056  *
2057  * @param pd data to be probed
2058  * @param is_opened Whether the file is already opened; determines whether
2059  * demuxers with or without AVFMT_NOFILE are probed.
2060  * @param score_max A probe score larger that this is required to accept a
2061  * detection, the variable is set to the actual detection
2062  * score afterwards.
2063  * If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
2064  * to retry with a larger probe buffer.
2065  */
2066 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max);
2067 
2068 /**
2069  * Guess the file format.
2070  *
2071  * @param is_opened Whether the file is already opened; determines whether
2072  * demuxers with or without AVFMT_NOFILE are probed.
2073  * @param score_ret The score of the best detection.
2074  */
2075 AVInputFormat *av_probe_input_format3(AVProbeData *pd, int is_opened, int *score_ret);
2076 
2077 /**
2078  * Probe a bytestream to determine the input format. Each time a probe returns
2079  * with a score that is too low, the probe buffer size is increased and another
2080  * attempt is made. When the maximum probe size is reached, the input format
2081  * with the highest score is returned.
2082  *
2083  * @param pb the bytestream to probe
2084  * @param fmt the input format is put here
2085  * @param url the url of the stream
2086  * @param logctx the log context
2087  * @param offset the offset within the bytestream to probe from
2088  * @param max_probe_size the maximum probe buffer size (zero for default)
2089  * @return the score in case of success, a negative value corresponding to an
2090  * the maximal score is AVPROBE_SCORE_MAX
2091  * AVERROR code otherwise
2092  */
2094  const char *url, void *logctx,
2095  unsigned int offset, unsigned int max_probe_size);
2096 
2097 /**
2098  * Like av_probe_input_buffer2() but returns 0 on success
2099  */
2101  const char *url, void *logctx,
2102  unsigned int offset, unsigned int max_probe_size);
2103 
2104 /**
2105  * Open an input stream and read the header. The codecs are not opened.
2106  * The stream must be closed with avformat_close_input().
2107  *
2108  * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
2109  * May be a pointer to NULL, in which case an AVFormatContext is allocated by this
2110  * function and written into ps.
2111  * Note that a user-supplied AVFormatContext will be freed on failure.
2112  * @param url URL of the stream to open.
2113  * @param fmt If non-NULL, this parameter forces a specific input format.
2114  * Otherwise the format is autodetected.
2115  * @param options A dictionary filled with AVFormatContext and demuxer-private options.
2116  * On return this parameter will be destroyed and replaced with a dict containing
2117  * options that were not found. May be NULL.
2118  *
2119  * @return 0 on success, a negative AVERROR on failure.
2120  *
2121  * @note If you want to use custom IO, preallocate the format context and set its pb field.
2122  */
2123 int avformat_open_input(AVFormatContext **ps, const char *url, AVInputFormat *fmt, AVDictionary **options);
2124 
2127 
2128 /**
2129  * Read packets of a media file to get stream information. This
2130  * is useful for file formats with no headers such as MPEG. This
2131  * function also computes the real framerate in case of MPEG-2 repeat
2132  * frame mode.
2133  * The logical file position is not changed by this function;
2134  * examined packets may be buffered for later processing.
2135  *
2136  * @param ic media file handle
2137  * @param options If non-NULL, an ic.nb_streams long array of pointers to
2138  * dictionaries, where i-th member contains options for
2139  * codec corresponding to i-th stream.
2140  * On return each dictionary will be filled with options that were not found.
2141  * @return >=0 if OK, AVERROR_xxx on error
2142  *
2143  * @note this function isn't guaranteed to open all the codecs, so
2144  * options being non-empty at return is a perfectly normal behavior.
2145  *
2146  * @todo Let the user decide somehow what information is needed so that
2147  * we do not waste time getting stuff the user does not need.
2148  */
2150 
2151 /**
2152  * Find the programs which belong to a given stream.
2153  *
2154  * @param ic media file handle
2155  * @param last the last found program, the search will start after this
2156  * program, or from the beginning if it is NULL
2157  * @param s stream index
2158  * @return the next program which belongs to s, NULL if no program is found or
2159  * the last program is not among the programs of ic.
2160  */
2162 
2163 /**
2164  * Find the "best" stream in the file.
2165  * The best stream is determined according to various heuristics as the most
2166  * likely to be what the user expects.
2167  * If the decoder parameter is non-NULL, av_find_best_stream will find the
2168  * default decoder for the stream's codec; streams for which no decoder can
2169  * be found are ignored.
2170  *
2171  * @param ic media file handle
2172  * @param type stream type: video, audio, subtitles, etc.
2173  * @param wanted_stream_nb user-requested stream number,
2174  * or -1 for automatic selection
2175  * @param related_stream try to find a stream related (eg. in the same
2176  * program) to this one, or -1 if none
2177  * @param decoder_ret if non-NULL, returns the decoder for the
2178  * selected stream
2179  * @param flags flags; none are currently defined
2180  * @return the non-negative stream number in case of success,
2181  * AVERROR_STREAM_NOT_FOUND if no stream with the requested type
2182  * could be found,
2183  * AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
2184  * @note If av_find_best_stream returns successfully and decoder_ret is not
2185  * NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
2186  */
2188  enum AVMediaType type,
2189  int wanted_stream_nb,
2190  int related_stream,
2191  AVCodec **decoder_ret,
2192  int flags);
2193 
2194 /**
2195  * Return the next frame of a stream.
2196  * This function returns what is stored in the file, and does not validate
2197  * that what is there are valid frames for the decoder. It will split what is
2198  * stored in the file into frames and return one for each call. It will not
2199  * omit invalid data between valid frames so as to give the decoder the maximum
2200  * information possible for decoding.
2201  *
2202  * If pkt->buf is NULL, then the packet is valid until the next
2203  * av_read_frame() or until avformat_close_input(). Otherwise the packet
2204  * is valid indefinitely. In both cases the packet must be freed with
2205  * av_free_packet when it is no longer needed. For video, the packet contains
2206  * exactly one frame. For audio, it contains an integer number of frames if each
2207  * frame has a known fixed size (e.g. PCM or ADPCM data). If the audio frames
2208  * have a variable size (e.g. MPEG audio), then it contains one frame.
2209  *
2210  * pkt->pts, pkt->dts and pkt->duration are always set to correct
2211  * values in AVStream.time_base units (and guessed if the format cannot
2212  * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
2213  * has B-frames, so it is better to rely on pkt->dts if you do not
2214  * decompress the payload.
2215  *
2216  * @return 0 if OK, < 0 on error or end of file
2217  */
2219 
2220 /**
2221  * Seek to the keyframe at timestamp.
2222  * 'timestamp' in 'stream_index'.
2223  *
2224  * @param s media file handle
2225  * @param stream_index If stream_index is (-1), a default
2226  * stream is selected, and timestamp is automatically converted
2227  * from AV_TIME_BASE units to the stream specific time_base.
2228  * @param timestamp Timestamp in AVStream.time_base units
2229  * or, if no stream is specified, in AV_TIME_BASE units.
2230  * @param flags flags which select direction and seeking mode
2231  * @return >= 0 on success
2232  */
2233 int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
2234  int flags);
2235 
2236 /**
2237  * Seek to timestamp ts.
2238  * Seeking will be done so that the point from which all active streams
2239  * can be presented successfully will be closest to ts and within min/max_ts.
2240  * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
2241  *
2242  * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
2243  * are the file position (this may not be supported by all demuxers).
2244  * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
2245  * in the stream with stream_index (this may not be supported by all demuxers).
2246  * Otherwise all timestamps are in units of the stream selected by stream_index
2247  * or if stream_index is -1, in AV_TIME_BASE units.
2248  * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
2249  * keyframes (this may not be supported by all demuxers).
2250  * If flags contain AVSEEK_FLAG_BACKWARD, it is ignored.
2251  *
2252  * @param s media file handle
2253  * @param stream_index index of the stream which is used as time base reference
2254  * @param min_ts smallest acceptable timestamp
2255  * @param ts target timestamp
2256  * @param max_ts largest acceptable timestamp
2257  * @param flags flags
2258  * @return >=0 on success, error code otherwise
2259  *
2260  * @note This is part of the new seek API which is still under construction.
2261  * Thus do not use this yet. It may change at any time, do not expect
2262  * ABI compatibility yet!
2263  */
2264 int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
2265 
2266 /**
2267  * Discard all internally buffered data. This can be useful when dealing with
2268  * discontinuities in the byte stream. Generally works only with formats that
2269  * can resync. This includes headerless formats like MPEG-TS/TS but should also
2270  * work with NUT, Ogg and in a limited way AVI for example.
2271  *
2272  * The set of streams, the detected duration, stream parameters and codecs do
2273  * not change when calling this function. If you want a complete reset, it's
2274  * better to open a new AVFormatContext.
2275  *
2276  * This does not flush the AVIOContext (s->pb). If necessary, call
2277  * avio_flush(s->pb) before calling this function.
2278  *
2279  * @param s media file handle
2280  * @return >=0 on success, error code otherwise
2281  */
2283 
2284 /**
2285  * Start playing a network-based stream (e.g. RTSP stream) at the
2286  * current position.
2287  */
2289 
2290 /**
2291  * Pause a network-based stream (e.g. RTSP stream).
2292  *
2293  * Use av_read_play() to resume it.
2294  */
2296 
2297 /**
2298  * Close an opened input AVFormatContext. Free it and all its contents
2299  * and set *s to NULL.
2300  */
2302 /**
2303  * @}
2304  */
2305 
2306 #define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
2307 #define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
2308 #define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
2309 #define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
2310 
2311 /**
2312  * @addtogroup lavf_encoding
2313  * @{
2314  */
2315 /**
2316  * Allocate the stream private data and write the stream header to
2317  * an output media file.
2318  *
2319  * @param s Media file handle, must be allocated with avformat_alloc_context().
2320  * Its oformat field must be set to the desired output format;
2321  * Its pb field must be set to an already opened AVIOContext.
2322  * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
2323  * On return this parameter will be destroyed and replaced with a dict containing
2324  * options that were not found. May be NULL.
2325  *
2326  * @return 0 on success, negative AVERROR on failure.
2327  *
2328  * @see av_opt_find, av_dict_set, avio_open, av_oformat_next.
2329  */
2331 
2332 /**
2333  * Write a packet to an output media file.
2334  *
2335  * This function passes the packet directly to the muxer, without any buffering
2336  * or reordering. The caller is responsible for correctly interleaving the
2337  * packets if the format requires it. Callers that want libavformat to handle
2338  * the interleaving should call av_interleaved_write_frame() instead of this
2339  * function.
2340  *
2341  * @param s media file handle
2342  * @param pkt The packet containing the data to be written. Note that unlike
2343  * av_interleaved_write_frame(), this function does not take
2344  * ownership of the packet passed to it (though some muxers may make
2345  * an internal reference to the input packet).
2346  * <br>
2347  * This parameter can be NULL (at any time, not just at the end), in
2348  * order to immediately flush data buffered within the muxer, for
2349  * muxers that buffer up data internally before writing it to the
2350  * output.
2351  * <br>
2352  * Packet's @ref AVPacket.stream_index "stream_index" field must be
2353  * set to the index of the corresponding stream in @ref
2354  * AVFormatContext.streams "s->streams". It is very strongly
2355  * recommended that timing information (@ref AVPacket.pts "pts", @ref
2356  * AVPacket.dts "dts", @ref AVPacket.duration "duration") is set to
2357  * correct values.
2358  * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
2359  *
2360  * @see av_interleaved_write_frame()
2361  */
2363 
2364 /**
2365  * Write a packet to an output media file ensuring correct interleaving.
2366  *
2367  * This function will buffer the packets internally as needed to make sure the
2368  * packets in the output file are properly interleaved in the order of
2369  * increasing dts. Callers doing their own interleaving should call
2370  * av_write_frame() instead of this function.
2371  *
2372  * @param s media file handle
2373  * @param pkt The packet containing the data to be written.
2374  * <br>
2375  * If the packet is reference-counted, this function will take
2376  * ownership of this reference and unreference it later when it sees
2377  * fit.
2378  * The caller must not access the data through this reference after
2379  * this function returns. If the packet is not reference-counted,
2380  * libavformat will make a copy.
2381  * <br>
2382  * This parameter can be NULL (at any time, not just at the end), to
2383  * flush the interleaving queues.
2384  * <br>
2385  * Packet's @ref AVPacket.stream_index "stream_index" field must be
2386  * set to the index of the corresponding stream in @ref
2387  * AVFormatContext.streams "s->streams". It is very strongly
2388  * recommended that timing information (@ref AVPacket.pts "pts", @ref
2389  * AVPacket.dts "dts", @ref AVPacket.duration "duration") is set to
2390  * correct values.
2391  *
2392  * @return 0 on success, a negative AVERROR on error. Libavformat will always
2393  * take care of freeing the packet, even if this function fails.
2394  *
2395  * @see av_write_frame(), AVFormatContext.max_interleave_delta
2396  */
2398 
2399 /**
2400  * Write a uncoded frame to an output media file.
2401  *
2402  * The frame must be correctly interleaved according to the container
2403  * specification; if not, then av_interleaved_write_frame() must be used.
2404  *
2405  * See av_interleaved_write_frame() for details.
2406  */
2407 int av_write_uncoded_frame(AVFormatContext *s, int stream_index,
2408  AVFrame *frame);
2409 
2410 /**
2411  * Write a uncoded frame to an output media file.
2412  *
2413  * If the muxer supports it, this function makes it possible to write an AVFrame
2414  * structure directly, without encoding it into a packet.
2415  * It is mostly useful for devices and similar special muxers that use raw
2416  * video or PCM data and will not serialize it into a byte stream.
2417  *
2418  * To test whether it is possible to use it with a given muxer and stream,
2419  * use av_write_uncoded_frame_query().
2420  *
2421  * The caller gives up ownership of the frame and must not access it
2422  * afterwards.
2423  *
2424  * @return >=0 for success, a negative code on error
2425  */
2426 int av_interleaved_write_uncoded_frame(AVFormatContext *s, int stream_index,
2427  AVFrame *frame);
2428 
2429 /**
2430  * Test whether a muxer supports uncoded frame.
2431  *
2432  * @return >=0 if an uncoded frame can be written to that muxer and stream,
2433  * <0 if not
2434  */
2435 int av_write_uncoded_frame_query(AVFormatContext *s, int stream_index);
2436 
2437 /**
2438  * Write the stream trailer to an output media file and free the
2439  * file private data.
2440  *
2441  * May only be called after a successful call to avformat_write_header.
2442  *
2443  * @param s media file handle
2444  * @return 0 if OK, AVERROR_xxx on error
2445  */
2447 
2448 /**
2449  * Return the output format in the list of registered output formats
2450  * which best matches the provided parameters, or return NULL if
2451  * there is no match.
2452  *
2453  * @param short_name if non-NULL checks if short_name matches with the
2454  * names of the registered formats
2455  * @param filename if non-NULL checks if filename terminates with the
2456  * extensions of the registered formats
2457  * @param mime_type if non-NULL checks if mime_type matches with the
2458  * MIME type of the registered formats
2459  */
2460 AVOutputFormat *av_guess_format(const char *short_name,
2461  const char *filename,
2462  const char *mime_type);
2463 
2464 /**
2465  * Guess the codec ID based upon muxer and filename.
2466  */
2467 enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
2468  const char *filename, const char *mime_type,
2469  enum AVMediaType type);
2470 
2471 /**
2472  * Get timing information for the data currently output.
2473  * The exact meaning of "currently output" depends on the format.
2474  * It is mostly relevant for devices that have an internal buffer and/or
2475  * work in real time.
2476  * @param s media file handle
2477  * @param stream stream in the media file
2478  * @param[out] dts DTS of the last packet output for the stream, in stream
2479  * time_base units
2480  * @param[out] wall absolute time when that packet whas output,
2481  * in microsecond
2482  * @return 0 if OK, AVERROR(ENOSYS) if the format does not support it
2483  * Note: some formats or devices may not allow to measure dts and wall
2484  * atomically.
2485  */
2486 int av_get_output_timestamp(struct AVFormatContext *s, int stream,
2487  int64_t *dts, int64_t *wall);
2488 
2489 
2490 /**
2491  * @}
2492  */
2493 
2494 
2495 /**
2496  * @defgroup lavf_misc Utility functions
2497  * @ingroup libavf
2498  * @{
2499  *
2500  * Miscellaneous utility functions related to both muxing and demuxing
2501  * (or neither).
2502  */
2503 
2504 /**
2505  * Send a nice hexadecimal dump of a buffer to the specified file stream.
2506  *
2507  * @param f The file stream pointer where the dump should be sent to.
2508  * @param buf buffer
2509  * @param size buffer size
2510  *
2511  * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
2512  */
2513 void av_hex_dump(FILE *f, const uint8_t *buf, int size);
2514 
2515 /**
2516  * Send a nice hexadecimal dump of a buffer to the log.
2517  *
2518  * @param avcl A pointer to an arbitrary struct of which the first field is a
2519  * pointer to an AVClass struct.
2520  * @param level The importance level of the message, lower values signifying
2521  * higher importance.
2522  * @param buf buffer
2523  * @param size buffer size
2524  *
2525  * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
2526  */
2527 void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
2528 
2529 /**
2530  * Send a nice dump of a packet to the specified file stream.
2531  *
2532  * @param f The file stream pointer where the dump should be sent to.
2533  * @param pkt packet to dump
2534  * @param dump_payload True if the payload must be displayed, too.
2535  * @param st AVStream that the packet belongs to
2536  */
2537 void av_pkt_dump2(FILE *f, const AVPacket *pkt, int dump_payload, const AVStream *st);
2538 
2539 
2540 /**
2541  * Send a nice dump of a packet to the log.
2542  *
2543  * @param avcl A pointer to an arbitrary struct of which the first field is a
2544  * pointer to an AVClass struct.
2545  * @param level The importance level of the message, lower values signifying
2546  * higher importance.
2547  * @param pkt packet to dump
2548  * @param dump_payload True if the payload must be displayed, too.
2549  * @param st AVStream that the packet belongs to
2550  */
2551 void av_pkt_dump_log2(void *avcl, int level, const AVPacket *pkt, int dump_payload,
2552  const AVStream *st);
2553 
2554 /**
2555  * Get the AVCodecID for the given codec tag tag.
2556  * If no codec id is found returns AV_CODEC_ID_NONE.
2557  *
2558  * @param tags list of supported codec_id-codec_tag pairs, as stored
2559  * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2560  * @param tag codec tag to match to a codec ID
2561  */
2562 enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
2563 
2564 /**
2565  * Get the codec tag for the given codec id id.
2566  * If no codec tag is found returns 0.
2567  *
2568  * @param tags list of supported codec_id-codec_tag pairs, as stored
2569  * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2570  * @param id codec ID to match to a codec tag
2571  */
2572 unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id);
2573 
2574 /**
2575  * Get the codec tag for the given codec id.
2576  *
2577  * @param tags list of supported codec_id - codec_tag pairs, as stored
2578  * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2579  * @param id codec id that should be searched for in the list
2580  * @param tag A pointer to the found tag
2581  * @return 0 if id was not found in tags, > 0 if it was found
2582  */
2583 int av_codec_get_tag2(const struct AVCodecTag * const *tags, enum AVCodecID id,
2584  unsigned int *tag);
2585 
2587 
2588 /**
2589  * Get the index for a specific timestamp.
2590  *
2591  * @param st stream that the timestamp belongs to
2592  * @param timestamp timestamp to retrieve the index for
2593  * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
2594  * to the timestamp which is <= the requested one, if backward
2595  * is 0, then it will be >=
2596  * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
2597  * @return < 0 if no such timestamp could be found
2598  */
2599 int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
2600 
2601 /**
2602  * Add an index entry into a sorted list. Update the entry if the list
2603  * already contains it.
2604  *
2605  * @param timestamp timestamp in the time base of the given stream
2606  */
2607 int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
2608  int size, int distance, int flags);
2609 
2610 
2611 /**
2612  * Split a URL string into components.
2613  *
2614  * The pointers to buffers for storing individual components may be null,
2615  * in order to ignore that component. Buffers for components not found are
2616  * set to empty strings. If the port is not found, it is set to a negative
2617  * value.
2618  *
2619  * @param proto the buffer for the protocol
2620  * @param proto_size the size of the proto buffer
2621  * @param authorization the buffer for the authorization
2622  * @param authorization_size the size of the authorization buffer
2623  * @param hostname the buffer for the host name
2624  * @param hostname_size the size of the hostname buffer
2625  * @param port_ptr a pointer to store the port number in
2626  * @param path the buffer for the path
2627  * @param path_size the size of the path buffer
2628  * @param url the URL to split
2629  */
2630 void av_url_split(char *proto, int proto_size,
2631  char *authorization, int authorization_size,
2632  char *hostname, int hostname_size,
2633  int *port_ptr,
2634  char *path, int path_size,
2635  const char *url);
2636 
2637 
2638 /**
2639  * Print detailed information about the input or output format, such as
2640  * duration, bitrate, streams, container, programs, metadata, side data,
2641  * codec and time base.
2642  *
2643  * @param ic the context to analyze
2644  * @param index index of the stream to dump information about
2645  * @param url the URL to print, such as source or destination file
2646  * @param is_output Select whether the specified context is an input(0) or output(1)
2647  */
2649  int index,
2650  const char *url,
2651  int is_output);
2652 
2653 /**
2654  * Return in 'buf' the path with '%d' replaced by a number.
2655  *
2656  * Also handles the '%0nd' format where 'n' is the total number
2657  * of digits and '%%'.
2658  *
2659  * @param buf destination buffer
2660  * @param buf_size destination buffer size
2661  * @param path numbered sequence string
2662  * @param number frame number
2663  * @return 0 if OK, -1 on format error
2664  */
2665 int av_get_frame_filename(char *buf, int buf_size,
2666  const char *path, int number);
2667 
2668 /**
2669  * Check whether filename actually is a numbered sequence generator.
2670  *
2671  * @param filename possible numbered sequence string
2672  * @return 1 if a valid numbered sequence string, 0 otherwise
2673  */
2674 int av_filename_number_test(const char *filename);
2675 
2676 /**
2677  * Generate an SDP for an RTP session.
2678  *
2679  * Note, this overwrites the id values of AVStreams in the muxer contexts
2680  * for getting unique dynamic payload types.
2681  *
2682  * @param ac array of AVFormatContexts describing the RTP streams. If the
2683  * array is composed by only one context, such context can contain
2684  * multiple AVStreams (one AVStream per RTP stream). Otherwise,
2685  * all the contexts in the array (an AVCodecContext per RTP stream)
2686  * must contain only one AVStream.
2687  * @param n_files number of AVCodecContexts contained in ac
2688  * @param buf buffer where the SDP will be stored (must be allocated by
2689  * the caller)
2690  * @param size the size of the buffer
2691  * @return 0 if OK, AVERROR_xxx on error
2692  */
2693 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
2694 
2695 /**
2696  * Return a positive value if the given filename has one of the given
2697  * extensions, 0 otherwise.
2698  *
2699  * @param filename file name to check against the given extensions
2700  * @param extensions a comma-separated list of filename extensions
2701  */
2702 int av_match_ext(const char *filename, const char *extensions);
2703 
2704 /**
2705  * Test if the given container can store a codec.
2706  *
2707  * @param ofmt container to check for compatibility
2708  * @param codec_id codec to potentially store in container
2709  * @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
2710  *
2711  * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
2712  * A negative number if this information is not available.
2713  */
2714 int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id,
2715  int std_compliance);
2716 
2717 /**
2718  * @defgroup riff_fourcc RIFF FourCCs
2719  * @{
2720  * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
2721  * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
2722  * following code:
2723  * @code
2724  * uint32_t tag = MKTAG('H', '2', '6', '4');
2725  * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
2726  * enum AVCodecID id = av_codec_get_id(table, tag);
2727  * @endcode
2728  */
2729 /**
2730  * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
2731  */
2732 const struct AVCodecTag *avformat_get_riff_video_tags(void);
2733 /**
2734  * @return the table mapping RIFF FourCCs for audio to AVCodecID.
2735  */
2736 const struct AVCodecTag *avformat_get_riff_audio_tags(void);
2737 /**
2738  * @return the table mapping MOV FourCCs for video to libavcodec AVCodecID.
2739  */
2740 const struct AVCodecTag *avformat_get_mov_video_tags(void);
2741 /**
2742  * @return the table mapping MOV FourCCs for audio to AVCodecID.
2743  */
2744 const struct AVCodecTag *avformat_get_mov_audio_tags(void);
2745 
2746 /**
2747  * @}
2748  */
2749 
2750 /**
2751  * Guess the sample aspect ratio of a frame, based on both the stream and the
2752  * frame aspect ratio.
2753  *
2754  * Since the frame aspect ratio is set by the codec but the stream aspect ratio
2755  * is set by the demuxer, these two may not be equal. This function tries to
2756  * return the value that you should use if you would like to display the frame.
2757  *
2758  * Basic logic is to use the stream aspect ratio if it is set to something sane
2759  * otherwise use the frame aspect ratio. This way a container setting, which is
2760  * usually easy to modify can override the coded value in the frames.
2761  *
2762  * @param format the format context which the stream is part of
2763  * @param stream the stream which the frame is part of
2764  * @param frame the frame with the aspect ratio to be determined
2765  * @return the guessed (valid) sample_aspect_ratio, 0/1 if no idea
2766  */
2768 
2769 /**
2770  * Guess the frame rate, based on both the container and codec information.
2771  *
2772  * @param ctx the format context which the stream is part of
2773  * @param stream the stream which the frame is part of
2774  * @param frame the frame for which the frame rate should be determined, may be NULL
2775  * @return the guessed (valid) frame rate, 0/1 if no idea
2776  */
2778 
2779 /**
2780  * Check if the stream st contained in s is matched by the stream specifier
2781  * spec.
2782  *
2783  * See the "stream specifiers" chapter in the documentation for the syntax
2784  * of spec.
2785  *
2786  * @return >0 if st is matched by spec;
2787  * 0 if st is not matched by spec;
2788  * AVERROR code if spec is invalid
2789  *
2790  * @note A stream specifier can match several streams in the format.
2791  */
2793  const char *spec);
2794 
2796 
2797 
2798 /**
2799  * @}
2800  */
2801 
2802 #endif /* AVFORMAT_AVFORMAT_H */
void av_url_split(char *proto, int proto_size, char *authorization, int authorization_size, char *hostname, int hostname_size, int *port_ptr, char *path, int path_size, const char *url)
Split a URL string into components.
full parsing and interpolation of timestamps for frames not starting on a packet boundary ...
Definition: avformat.h:807
Bytestream IO Context.
Definition: avio.h:111
void av_pkt_dump2(FILE *f, const AVPacket *pkt, int dump_payload, const AVStream *st)
Send a nice dump of a packet to the specified file stream.
Buffered I/O operations.
AVPacketSideDataType
Definition: avcodec.h:1224
attribute_deprecated int av_demuxer_open(AVFormatContext *ic)
This structure describes decoded (raw) audio or video data.
Definition: frame.h:171
AVCodec * av_format_get_video_codec(const AVFormatContext *s)
int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
Write a packet to an output media file ensuring correct interleaving.
int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp, int size, int distance, int flags)
Add an index entry into a sorted list.
int avformat_write_header(AVFormatContext *s, AVDictionary **options)
Allocate the stream private data and write the stream header to an output media file.
int av_write_frame(AVFormatContext *s, AVPacket *pkt)
Write a packet to an output media file.
const char * filename
Definition: avformat.h:461
AVRational av_guess_sample_aspect_ratio(AVFormatContext *format, AVStream *stream, AVFrame *frame)
Guess the sample aspect ratio of a frame, based on both the stream and the frame aspect ratio...
enum AVCodecID video_codec
default video codec
Definition: avformat.h:536
void av_stream_set_r_frame_rate(AVStream *s, AVRational r)
uint8_t * av_stream_get_side_data(AVStream *stream, enum AVPacketSideDataType type, int *size)
Get side information from stream.
int av_get_output_timestamp(struct AVFormatContext *s, int stream, int64_t *dts, int64_t *wall)
Get timing information for the data currently output.
AVInputFormat * av_probe_input_format3(AVProbeData *pd, int is_opened, int *score_ret)
Guess the file format.
static AVPacket pkt
int av_write_uncoded_frame_query(AVFormatContext *s, int stream_index)
Test whether a muxer supports uncoded frame.
int priv_data_size
Size of private data so that it can be allocated in the wrapper.
Definition: avformat.h:710
AVCodec.
Definition: avcodec.h:3482
void av_format_set_subtitle_codec(AVFormatContext *s, AVCodec *c)
enum AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext *ctx)
Returns the method used to set ctx->duration.
Format I/O context.
Definition: avformat.h:1304
AVRational av_guess_frame_rate(AVFormatContext *ctx, AVStream *stream, AVFrame *frame)
Guess the frame rate, based on both the container and codec information.
const struct AVCodecTag * avformat_get_mov_audio_tags(void)
Public dictionary API.
int flags
can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_RAWPICTURE, AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS, AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH, AVFMT_TS_NONSTRICT
Definition: avformat.h:544
const struct AVCodecTag * avformat_get_riff_video_tags(void)
enum AVCodecID av_codec_get_id(const struct AVCodecTag *const *tags, unsigned int tag)
Get the AVCodecID for the given codec tag tag.
unsigned avformat_version(void)
Return the LIBAVFORMAT_VERSION_INT constant.
const char * avformat_license(void)
Return the libavformat license.
struct AVFormatInternal AVFormatInternal
Definition: avformat.h:1294
int priv_data_size
size of private data so that it can be allocated in the wrapper
Definition: avformat.h:566
int avformat_match_stream_specifier(AVFormatContext *s, AVStream *st, const char *spec)
Check if the stream st contained in s is matched by the stream specifier spec.
AVDurationEstimationMethod
The duration of a video can be estimated through various ways, and this enum can be used to know how ...
Definition: avformat.h:1288
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
int av_codec_get_tag2(const struct AVCodecTag *const *tags, enum AVCodecID id, unsigned int *tag)
Get the codec tag for the given codec id.
static AVFrame * frame
AVFormatContext * avformat_alloc_context(void)
Allocate an AVFormatContext.
void av_pkt_dump_log2(void *avcl, int level, const AVPacket *pkt, int dump_payload, const AVStream *st)
Send a nice dump of a packet to the log.
const char * avformat_configuration(void)
Return the libavformat build-time configuration.
#define MAX_REORDER_DELAY
Definition: avformat.h:1073
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1415
AVProgram * av_new_program(AVFormatContext *s, int id)
int avformat_network_init(void)
Do global initialization of network components.
const struct AVCodecTag * avformat_get_riff_audio_tags(void)
int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size)
Generate an SDP for an RTP session.
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
int av_match_ext(const char *filename, const char *extensions)
Return a positive value if the given filename has one of the given extensions, 0 otherwise.
const AVClass * avformat_get_class(void)
Get the AVClass for AVFormatContext.
int av_probe_input_buffer2(AVIOContext *pb, AVInputFormat **fmt, const char *url, void *logctx, unsigned int offset, unsigned int max_probe_size)
Probe a bytestream to determine the input format.
AVCodec * av_format_get_audio_codec(const AVFormatContext *s)
full parsing and repack with timestamp and position generation by parser for raw this assumes that ea...
Definition: avformat.h:809
Duration estimated from bitrate (less accurate)
Definition: avformat.h:1291
int av_append_packet(AVIOContext *s, AVPacket *pkt, int size)
Read data and append it to the current content of the AVPacket.
const struct AVCodecTag * avformat_get_mov_video_tags(void)
int avformat_alloc_output_context2(AVFormatContext **ctx, AVOutputFormat *oformat, const char *format_name, const char *filename)
Allocate an AVFormatContext for an output format.
void av_dump_format(AVFormatContext *ic, int index, const char *url, int is_output)
Print detailed information about the input or output format, such as duration, bitrate, streams, container, programs, metadata, side data, codec and time base.
Callback for checking whether to abort blocking functions.
Definition: avio.h:50
int av_find_best_stream(AVFormatContext *ic, enum AVMediaType type, int wanted_stream_nb, int related_stream, AVCodec **decoder_ret, int flags)
Find the "best" stream in the file.
int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt, const char *url, void *logctx, unsigned int offset, unsigned int max_probe_size)
Like av_probe_input_buffer2() but returns 0 on success.
AVProgram * av_find_program_from_stream(AVFormatContext *ic, AVProgram *last, int s)
Find the programs which belong to a given stream.
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:102
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
void av_hex_dump(FILE *f, const uint8_t *buf, int size)
Send a nice hexadecimal dump of a buffer to the specified file stream.
struct AVCodecParser * parser
Definition: avcodec.h:4551
void av_format_set_data_codec(AVFormatContext *s, AVCodec *c)
AVCodec * av_format_get_subtitle_codec(const AVFormatContext *s)
struct AVCodecParserContext * av_stream_get_parser(const AVStream *s)
struct AVDictionary AVDictionary
Definition: dict.h:91
int av_read_play(AVFormatContext *s)
Start playing a network-based stream (e.g.
New fields can be added to the end with minor version bumps.
Definition: avformat.h:1237
Libavcodec external API header.
AVInputFormat * av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
Guess the file format.
void * opaque
User data.
Definition: avformat.h:1783
Only parse headers, do not repack.
Definition: avformat.h:806
int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id, int std_compliance)
Test if the given container can store a codec.
const char * mime_type
mime_type, when known.
Definition: avformat.h:464
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:463
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:462
void av_format_inject_global_side_data(AVFormatContext *s)
This function will cause global side data to be injected in the next packet of each stream as well as...
void av_stream_set_recommended_encoder_configuration(AVStream *s, char *configuration)
int av_read_pause(AVFormatContext *s)
Pause a network-based stream (e.g.
AVInputFormat * av_find_input_format(const char *short_name)
Find AVInputFormat based on the short name of the input format.
int(* write_header)(struct AVFormatContext *)
Definition: avformat.h:568
int(* av_format_control_message)(struct AVFormatContext *s, int type, void *data, size_t data_size)
Callback used by devices to communicate with application.
Definition: avformat.h:1278
enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name, const char *filename, const char *mime_type, enum AVMediaType type)
Guess the codec ID based upon muxer and filename.
int max_streams
The maximum number of streams.
Definition: avformat.h:1859
int av_find_default_stream_index(AVFormatContext *s)
void av_format_set_opaque(AVFormatContext *s, void *opaque)
Duration estimated from a stream with a known duration.
Definition: avformat.h:1290
AVOutputFormat * av_guess_format(const char *short_name, const char *filename, const char *mime_type)
Return the output format in the list of registered output formats which best matches the provided par...
void av_register_input_format(AVInputFormat *format)
void av_format_set_audio_codec(AVFormatContext *s, AVCodec *c)
Libavformat version macros.
int(* AVOpenCallback)(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options)
Definition: avformat.h:1281
AVOutputFormat * av_oformat_next(const AVOutputFormat *f)
If f is NULL, returns the first registered output format, if f is non-NULL, returns the next register...
void * av_format_get_opaque(const AVFormatContext *s)
int av_get_frame_filename(char *buf, int buf_size, const char *path, int number)
Return in &#39;buf&#39; the path with &#39;d&#39; replaced by a number.
int av_format_get_probe_score(const AVFormatContext *s)
Stream structure.
Definition: avformat.h:873
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
int avformat_queue_attached_pictures(AVFormatContext *s)
void av_register_output_format(AVOutputFormat *format)
int avformat_network_deinit(void)
Undo the initialization done by avformat_network_init.
struct AVOutputFormat * next
Definition: avformat.h:562
AVIOContext * pb
I/O context.
Definition: avformat.h:1346
main external API structure.
Definition: avcodec.h:1512
int av_filename_number_test(const char *filename)
Check whether filename actually is a numbered sequence generator.
void av_format_set_video_codec(AVFormatContext *s, AVCodec *c)
Describe the class of an AVClass context structure.
Definition: log.h:67
enum AVCodecID subtitle_codec
default subtitle codec
Definition: avformat.h:537
rational number numerator/denominator
Definition: rational.h:43
AVRational av_stream_get_r_frame_rate(const AVStream *s)
AVMediaType
Definition: avutil.h:191
void av_format_set_open_cb(AVFormatContext *s, AVOpenCallback callback)
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
This structure contains the data a format has to probe a file.
Definition: avformat.h:460
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
List of devices.
Definition: avdevice.h:459
int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Seek to timestamp ts.
full parsing and repack of the first frame only, only implemented for H.264 currently ...
Definition: avformat.h:808
int raw_codec_id
Raw demuxers store their codec ID here.
Definition: avformat.h:705
static int64_t pts
Global timestamp for the audio frames.
av_format_control_message av_format_get_control_message_cb(const AVFormatContext *s)
#define attribute_deprecated
Definition: attributes.h:86
Duration accurately estimated from PTSes.
Definition: avformat.h:1289
int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Seek to the keyframe at timestamp.
AVOpenCallback av_format_get_open_cb(const AVFormatContext *s)
full parsing and repack
Definition: avformat.h:805
int av_interleaved_write_uncoded_frame(AVFormatContext *s, int stream_index, AVFrame *frame)
Write a uncoded frame to an output media file.
struct AVPacketList * next
Definition: avformat.h:1895
enum AVCodecID data_codec
default data codec
Definition: avformat.h:625
int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
Read packets of a media file to get stream information.
AVStreamParseType
Definition: avformat.h:803
void avformat_close_input(AVFormatContext **s)
Close an opened input AVFormatContext.
int av_write_uncoded_frame(AVFormatContext *s, int stream_index, AVFrame *frame)
Write a uncoded frame to an output media file.
int(* read_header)(struct AVFormatContext *)
Read the format header and initialize the AVFormatContext structure.
Definition: avformat.h:724
enum AVCodecID audio_codec
default audio codec
Definition: avformat.h:535
void av_format_set_control_message_cb(AVFormatContext *s, av_format_control_message callback)
int avformat_open_input(AVFormatContext **ps, const char *url, AVInputFormat *fmt, AVDictionary **options)
Open an input stream and read the header.
AVDiscard
Definition: avcodec.h:680
int av_format_get_metadata_header_padding(const AVFormatContext *s)
char * av_stream_get_recommended_encoder_configuration(const AVStream *s)
int av_write_trailer(AVFormatContext *s)
Write the stream trailer to an output media file and free the file private data.
int avformat_flush(AVFormatContext *s)
Discard all internally buffered data.
void av_format_set_metadata_header_padding(AVFormatContext *s, int c)
int(* read_probe)(AVProbeData *)
Tell if a given file has a chance of being parsed as this format.
Definition: avformat.h:717
void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size)
Send a nice hexadecimal dump of a buffer to the log.
struct AVInputFormat * next
Definition: avformat.h:700
AVCodec * av_format_get_data_codec(const AVFormatContext *s)
#define MKTAG(a, b, c, d)
Definition: common.h:341
unsigned int av_codec_get_tag(const struct AVCodecTag *const *tags, enum AVCodecID id)
Get the codec tag for the given codec id id.
AVInputFormat * av_probe_input_format(AVProbeData *pd, int is_opened)
Guess the file format.
Following API allows user to probe device capabilities (supported codecs, pixel formats, sample formats, resolutions, channel counts, etc).
Definition: avdevice.h:399
This structure stores compressed data.
Definition: avcodec.h:1410
void av_register_all(void)
Initialize libavformat and register all the muxers, demuxers and protocols.
#define MAX_STD_TIMEBASES
Stream information used internally by av_find_stream_info()
Definition: avformat.h:1010
int64_t av_stream_get_end_pts(const AVStream *st)
Returns the pts of the last muxed packet + its duration.
AVInputFormat * av_iformat_next(const AVInputFormat *f)
If f is NULL, returns the first registered input format, if f is non-NULL, returns the next registere...