avformat.h source code [include/libavformat/avformat.h]

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 libavformat
32	* I/O and Muxing/Demuxing Library
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).
40	* Unless you are absolutely sure you won't use libavformat's network
41	* capabilities, you should also call avformat_network_init().
42	*
43	* A supported input format is described by an AVInputFormat struct, conversely
44	* an output format is described by AVOutputFormat. You can iterate over all
45	* input/output formats using the av_demuxer_iterate / av_muxer_iterate() functions.
46	* The protocols layer is not part of the public API, so you can only get the names
47	* of supported protocols with the avio_enum_protocols() function.
48	*
49	* Main lavf structure used for both muxing and demuxing is AVFormatContext,
50	* which exports all information about the file being read or written. As with
51	* most Libavformat structures, its size is not part of public ABI, so it cannot be
52	* allocated on stack or directly with av_malloc(). To create an
53	* AVFormatContext, use avformat_alloc_context() (some functions, like
54	* avformat_open_input() might do that for you).
55	*
56	* Most importantly an AVFormatContext contains:
57	* @li the @ref AVFormatContext.iformat "input" or @ref AVFormatContext.oformat
58	* "output" format. It is either autodetected or set by user for input;
59	* always set by user for output.
60	* @li an @ref AVFormatContext.streams "array" of AVStreams, which describe all
61	* elementary streams stored in the file. AVStreams are typically referred to
62	* using their index in this array.
63	* @li an @ref AVFormatContext.pb "I/O context". It is either opened by lavf or
64	* set by user for input, always set by user for output (unless you are dealing
65	* with an AVFMT_NOFILE format).
66	*
67	* @section lavf_options Passing options to (de)muxers
68	* It is possible to configure lavf muxers and demuxers using the @ref avoptions
69	* mechanism. Generic (format-independent) libavformat options are provided by
70	* AVFormatContext, they can be examined from a user program by calling
71	* av_opt_next() / av_opt_find() on an allocated AVFormatContext (or its AVClass
72	* from avformat_get_class()). Private (format-specific) options are provided by
73	* AVFormatContext.priv_data if and only if AVInputFormat.priv_class /
74	* AVOutputFormat.priv_class of the corresponding format struct is non-NULL.
75	* Further options may be provided by the @ref AVFormatContext.pb "I/O context",
76	* if its AVClass is non-NULL, and the protocols layer. See the discussion on
77	* nesting in @ref avoptions documentation to learn how to access those.
78	*
79	* @section urls
80	* URL strings in libavformat are made of a scheme/protocol, a ':', and a
81	* scheme specific string. URLs without a scheme and ':' used for local files
82	* are supported but deprecated. "file:" should be used for local files.
83	*
84	* It is important that the scheme string is not taken from untrusted
85	* sources without checks.
86	*
87	* Note that some schemes/protocols are quite powerful, allowing access to
88	* both local and remote files, parts of them, concatenations of them, local
89	* audio and video devices and so on.
90	*
91	* @{
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_send_packet() or avcodec_decode_subtitle2() if the
165	* 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	* A packet returned by av_read_frame() is always reference-counted,
174	* i.e. AVPacket.buf is set and the user may keep it indefinitely.
175	* The packet must be freed with av_packet_unref() when it is no
176	* longer needed.
177	*
178	* @section lavf_decoding_seek Seeking
179	* @}
180	*
181	* @defgroup lavf_encoding Muxing
182	* @{
183	* Muxers take encoded data in the form of @ref AVPacket "AVPackets" and write
184	* it into files or other output bytestreams in the specified container format.
185	*
186	* The main API functions for muxing are avformat_write_header() for writing the
187	* file header, av_write_frame() / av_interleaved_write_frame() for writing the
188	* packets and av_write_trailer() for finalizing the file.
189	*
190	* At the beginning of the muxing process, the caller must first call
191	* avformat_alloc_context() to create a muxing context. The caller then sets up
192	* the muxer by filling the various fields in this context:
193	*
194	* - The @ref AVFormatContext.oformat "oformat" field must be set to select the
195	* muxer that will be used.
196	* - Unless the format is of the AVFMT_NOFILE type, the @ref AVFormatContext.pb
197	* "pb" field must be set to an opened IO context, either returned from
198	* avio_open2() or a custom one.
199	* - Unless the format is of the AVFMT_NOSTREAMS type, at least one stream must
200	* be created with the avformat_new_stream() function. The caller should fill
201	* the @ref AVStream.codecpar "stream codec parameters" information, such as the
202	* codec @ref AVCodecParameters.codec_type "type", @ref AVCodecParameters.codec_id
203	* "id" and other parameters (e.g. width / height, the pixel or sample format,
204	* etc.) as known. The @ref AVStream.time_base "stream timebase" should
205	* be set to the timebase that the caller desires to use for this stream (note
206	* that the timebase actually used by the muxer can be different, as will be
207	* described later).
208	* - It is advised to manually initialize only the relevant fields in
209	* AVCodecParameters, rather than using @ref avcodec_parameters_copy() during
210	* remuxing: there is no guarantee that the codec context values remain valid
211	* for both input and output format contexts.
212	* - The caller may fill in additional information, such as @ref
213	* AVFormatContext.metadata "global" or @ref AVStream.metadata "per-stream"
214	* metadata, @ref AVFormatContext.chapters "chapters", @ref
215	* AVFormatContext.programs "programs", etc. as described in the
216	* AVFormatContext documentation. Whether such information will actually be
217	* stored in the output depends on what the container format and the muxer
218	* support.
219	*
220	* When the muxing context is fully set up, the caller must call
221	* avformat_write_header() to initialize the muxer internals and write the file
222	* header. Whether anything actually is written to the IO context at this step
223	* depends on the muxer, but this function must always be called. Any muxer
224	* private options must be passed in the options parameter to this function.
225	*
226	* The data is then sent to the muxer by repeatedly calling av_write_frame() or
227	* av_interleaved_write_frame() (consult those functions' documentation for
228	* discussion on the difference between them; only one of them may be used with
229	* a single muxing context, they should not be mixed). Do note that the timing
230	* information on the packets sent to the muxer must be in the corresponding
231	* AVStream's timebase. That timebase is set by the muxer (in the
232	* avformat_write_header() step) and may be different from the timebase
233	* requested by the caller.
234	*
235	* Once all the data has been written, the caller must call av_write_trailer()
236	* to flush any buffered packets and finalize the output file, then close the IO
237	* context (if any) and finally free the muxing context with
238	* avformat_free_context().
239	* @}
240	*
241	* @defgroup lavf_io I/O Read/Write
242	* @{
243	* @section lavf_io_dirlist Directory listing
244	* The directory listing API makes it possible to list files on remote servers.
245	*
246	* Some of possible use cases:
247	* - an "open file" dialog to choose files from a remote location,
248	* - a recursive media finder providing a player with an ability to play all
249	* files from a given directory.
250	*
251	* @subsection lavf_io_dirlist_open Opening a directory
252	* At first, a directory needs to be opened by calling avio_open_dir()
253	* supplied with a URL and, optionally, ::AVDictionary containing
254	* protocol-specific parameters. The function returns zero or positive
255	* integer and allocates AVIODirContext on success.
256	*
257	* @code
258	* AVIODirContext *ctx = NULL;
259	* if (avio_open_dir(&ctx, "smb://example.com/some_dir", NULL) < 0) {
260	* fprintf(stderr, "Cannot open directory.\n");
261	* abort();
262	* }
263	* @endcode
264	*
265	* This code tries to open a sample directory using smb protocol without
266	* any additional parameters.
267	*
268	* @subsection lavf_io_dirlist_read Reading entries
269	* Each directory's entry (i.e. file, another directory, anything else
270	* within ::AVIODirEntryType) is represented by AVIODirEntry.
271	* Reading consecutive entries from an opened AVIODirContext is done by
272	* repeatedly calling avio_read_dir() on it. Each call returns zero or
273	* positive integer if successful. Reading can be stopped right after the
274	* NULL entry has been read -- it means there are no entries left to be
275	* read. The following code reads all entries from a directory associated
276	* with ctx and prints their names to standard output.
277	* @code
278	* AVIODirEntry *entry = NULL;
279	* for (;;) {
280	* if (avio_read_dir(ctx, &entry) < 0) {
281	* fprintf(stderr, "Cannot list directory.\n");
282	* abort();
283	* }
284	* if (!entry)
285	* break;
286	* printf("%s\n", entry->name);
287	* avio_free_directory_entry(&entry);
288	* }
289	* @endcode
290	* @}
291	*
292	* @defgroup lavf_codec Demuxers
293	* @{
294	* @defgroup lavf_codec_native Native Demuxers
295	* @{
296	* @}
297	* @defgroup lavf_codec_wrappers External library wrappers
298	* @{
299	* @}
300	* @}
301	* @defgroup lavf_protos I/O Protocols
302	* @{
303	* @}
304	* @defgroup lavf_internal Internal
305	* @{
306	* @}
307	* @}
308	*/
309
310	#include <stdio.h> /* FILE */
311
312	#include "libavcodec/codec_par.h"
313	#include "libavcodec/defs.h"
314	#include "libavcodec/packet.h"
315
316	#include "libavutil/dict.h"
317	#include "libavutil/log.h"
318
319	#include "avio.h"
320	#include "libavformat/version_major.h"
321	#ifndef HAVE_AV_CONFIG_H
322	/ When included as part of the ffmpeg build, only include the major version*
323	* to avoid unnecessary rebuilds. When included externally, keep including
324	* the full version information. */
325	#include "libavformat/version.h"
326
327	#include "libavutil/frame.h"
328	#include "libavcodec/codec.h"
329	#endif
330
331	struct AVFormatContext;
332	struct AVFrame;
333	struct AVDeviceInfoList;
334
335	/**
336	* @defgroup metadata_api Public Metadata API
337	* @{
338	* @ingroup libavf
339	* The metadata API allows libavformat to export metadata tags to a client
340	* application when demuxing. Conversely it allows a client application to
341	* set metadata when muxing.
342	*
343	* Metadata is exported or set as pairs of key/value strings in the 'metadata'
344	* fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
345	* using the @ref lavu_dict "AVDictionary" API. Like all strings in FFmpeg,
346	* metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
347	* exported by demuxers isn't checked to be valid UTF-8 in most cases.
348	*
349	* Important concepts to keep in mind:
350	* - Keys are unique; there can never be 2 tags with the same key. This is
351	* also meant semantically, i.e., a demuxer should not knowingly produce
352	* several keys that are literally different but semantically identical.
353	* E.g., key=Author5, key=Author6. In this example, all authors must be
354	* placed in the same tag.
355	* - Metadata is flat, not hierarchical; there are no subtags. If you
356	* want to store, e.g., the email address of the child of producer Alice
357	* and actor Bob, that could have key=alice_and_bobs_childs_email_address.
358	* - Several modifiers can be applied to the tag name. This is done by
359	* appending a dash character ('-') and the modifier name in the order
360	* they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
361	* - language -- a tag whose value is localized for a particular language
362	* is appended with the ISO 639-2/B 3-letter language code.
363	* For example: Author-ger=Michael, Author-eng=Mike
364	* The original/default language is in the unqualified "Author" tag.
365	* A demuxer should set a default if it sets any translated tag.
366	* - sorting -- a modified version of a tag that should be used for
367	* sorting will have '-sort' appended. E.g. artist="The Beatles",
368	* artist-sort="Beatles, The".
369	* - Some protocols and demuxers support metadata updates. After a successful
370	* call to av_read_frame(), AVFormatContext.event_flags or AVStream.event_flags
371	* will be updated to indicate if metadata changed. In order to detect metadata
372	* changes on a stream, you need to loop through all streams in the AVFormatContext
373	* and check their individual event_flags.
374	*
375	* - Demuxers attempt to export metadata in a generic format, however tags
376	* with no generic equivalents are left as they are stored in the container.
377	* Follows a list of generic tag names:
378	*
379	@verbatim
380	album -- name of the set this work belongs to
381	album_artist -- main creator of the set/album, if different from artist.
382	e.g. "Various Artists" for compilation albums.
383	artist -- main creator of the work
384	comment -- any additional description of the file.
385	composer -- who composed the work, if different from artist.
386	copyright -- name of copyright holder.
387	creation_time-- date when the file was created, preferably in ISO 8601.
388	date -- date when the work was created, preferably in ISO 8601.
389	disc -- number of a subset, e.g. disc in a multi-disc collection.
390	encoder -- name/settings of the software/hardware that produced the file.
391	encoded_by -- person/group who created the file.
392	filename -- original name of the file.
393	genre -- <self-evident>.
394	language -- main language in which the work is performed, preferably
395	in ISO 639-2 format. Multiple languages can be specified by
396	separating them with commas.
397	performer -- artist who performed the work, if different from artist.
398	E.g for "Also sprach Zarathustra", artist would be "Richard
399	Strauss" and performer "London Philharmonic Orchestra".
400	publisher -- name of the label/publisher.
401	service_name -- name of the service in broadcasting (channel name).
402	service_provider -- name of the service provider in broadcasting.
403	title -- name of the work.
404	track -- number of this work in the set, can be in form current/total.
405	variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
406	@endverbatim
407	*
408	* Look in the examples section for an application example how to use the Metadata API.
409	*
410	* @}
411	*/
412
413	/ packet functions /
414
415
416	/**
417	* Allocate and read the payload of a packet and initialize its
418	* fields with default values.
419	*
420	* @param s associated IO context
421	* @param pkt packet
422	* @param size desired payload size
423	* @return >0 (read size) if OK, AVERROR_xxx otherwise
424	*/
425	int av_get_packet(AVIOContext s, AVPacket pkt, int size);
426
427
428	/**
429	* Read data and append it to the current content of the AVPacket.
430	* If pkt->size is 0 this is identical to av_get_packet.
431	* Note that this uses av_grow_packet and thus involves a realloc
432	* which is inefficient. Thus this function should only be used
433	* when there is no reasonable way to know (an upper bound of)
434	* the final size.
435	*
436	* @param s associated IO context
437	* @param pkt packet
438	* @param size amount of data to read
439	* @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
440	* will not be lost even if an error occurs.
441	*/
442	int av_append_packet(AVIOContext s, AVPacket pkt, int size);
443
444	/***********************************************/
445	/ input/output formats /
446
447	struct AVCodecTag;
448
449	/**
450	* This structure contains the data a format has to probe a file.
451	*/
452	typedef struct AVProbeData {
453	const char *filename;
454	unsigned char buf; /*< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. /*
455	int buf_size; /< Size of buf except extra allocated bytes /*
456	const char mime_type; /*< mime_type, when known. /*
457	} AVProbeData;
458
459	#define AVPROBE_SCORE_RETRY (AVPROBE_SCORE_MAX/4)
460	#define AVPROBE_SCORE_STREAM_RETRY (AVPROBE_SCORE_MAX/4-1)
461
462	#define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
463	#define AVPROBE_SCORE_MIME 75 ///< score for file mime type
464	#define AVPROBE_SCORE_MAX 100 ///< maximum score
465
466	#define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
467
468	/// Demuxer will use avio_open, no opened file should be provided by the caller.
469	#define AVFMT_NOFILE 0x0001
470	#define AVFMT_NEEDNUMBER 0x0002 /*< Needs '%d' in filename. /
471	/**
472	* The muxer/demuxer is experimental and should be used with caution.
473	*
474	* - demuxers: will not be selected automatically by probing, must be specified
475	* explicitly.
476	*/
477	#define AVFMT_EXPERIMENTAL 0x0004
478	#define AVFMT_SHOW_IDS 0x0008 /*< Show format stream IDs numbers. /
479	#define AVFMT_GLOBALHEADER 0x0040 /*< Format wants global header. /
480	#define AVFMT_NOTIMESTAMPS 0x0080 /*< Format does not need / have any timestamps. /
481	#define AVFMT_GENERIC_INDEX 0x0100 /*< Use generic index building code. /
482	#define AVFMT_TS_DISCONT 0x0200 /*< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps /
483	#define AVFMT_VARIABLE_FPS 0x0400 /*< Format allows variable fps. /
484	#define AVFMT_NODIMENSIONS 0x0800 /*< Format does not need width/height /
485	#define AVFMT_NOSTREAMS 0x1000 /*< Format does not require any streams /
486	#define AVFMT_NOBINSEARCH 0x2000 /*< Format does not allow to fall back on binary search via read_timestamp /
487	#define AVFMT_NOGENSEARCH 0x4000 /*< Format does not allow to fall back on generic search /
488	#define AVFMT_NO_BYTE_SEEK 0x8000 /*< Format does not allow seeking by bytes /
489	#if FF_API_ALLOW_FLUSH
490	#define AVFMT_ALLOW_FLUSH 0x10000 /*< @deprecated: Just send a NULL packet if you want to flush a muxer. /
491	#endif
492	#define AVFMT_TS_NONSTRICT 0x20000 /**< Format does not require strictly
493	increasing timestamps, but they must
494	still be monotonic */
495	#define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative
496	timestamps. If not set the timestamp
497	will be shifted in av_write_frame and
498	av_interleaved_write_frame so they
499	start from 0.
500	The user or muxer can override this through
501	AVFormatContext.avoid_negative_ts
502	*/
503
504	#define AVFMT_SEEK_TO_PTS 0x4000000 /*< Seeking is based on PTS /
505
506	/**
507	* @addtogroup lavf_encoding
508	* @{
509	*/
510	typedef struct AVOutputFormat {
511	const char *name;
512	/**
513	* Descriptive name for the format, meant to be more human-readable
514	* than name. You should use the NULL_IF_CONFIG_SMALL() macro
515	* to define it.
516	*/
517	const char *long_name;
518	const char *mime_type;
519	const char extensions; /*< comma-separated filename extensions /*
520	/ output support /
521	enum AVCodecID audio_codec; /< default audio codec /*
522	enum AVCodecID video_codec; /< default video codec /*
523	enum AVCodecID subtitle_codec; /< default subtitle codec /*
524	/**
525	* can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER,
526	* AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
527	* AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS,
528	* AVFMT_TS_NONSTRICT, AVFMT_TS_NEGATIVE
529	*/
530	int flags;
531
532	/**
533	* List of supported codec_id-codec_tag pairs, ordered by "better
534	* choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
535	*/
536	const struct AVCodecTag * const *codec_tag;
537
538
539	const AVClass priv_class; ///< AVClass for the private context*
540	} AVOutputFormat;
541	/**
542	* @}
543	*/
544
545	/**
546	* @addtogroup lavf_decoding
547	* @{
548	*/
549	typedef struct AVInputFormat {
550	/**
551	* A comma separated list of short names for the format. New names
552	* may be appended with a minor bump.
553	*/
554	const char *name;
555
556	/**
557	* Descriptive name for the format, meant to be more human-readable
558	* than name. You should use the NULL_IF_CONFIG_SMALL() macro
559	* to define it.
560	*/
561	const char *long_name;
562
563	/**
564	* Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
565	* AVFMT_NOTIMESTAMPS, AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
566	* AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK, AVFMT_SEEK_TO_PTS.
567	*/
568	int flags;
569
570	/**
571	* If extensions are defined, then no probe is done. You should
572	* usually not use extension format guessing because it is not
573	* reliable enough
574	*/
575	const char *extensions;
576
577	const struct AVCodecTag * const *codec_tag;
578
579	const AVClass priv_class; ///< AVClass for the private context*
580
581	/**
582	* Comma-separated list of mime types.
583	* It is used check for matching mime types while probing.
584	* @see av_probe_input_format2
585	*/
586	const char *mime_type;
587
588	/*****************************************************************
589	* No fields below this line are part of the public API. They
590	* may not be used outside of libavformat and can be changed and
591	* removed at will.
592	* New public fields should be added right above.
593	*****************************************************************
594	*/
595	/**
596	* Raw demuxers store their codec ID here.
597	*/
598	int raw_codec_id;
599
600	/**
601	* Size of private data so that it can be allocated in the wrapper.
602	*/
603	int priv_data_size;
604
605	/**
606	* Internal flags. See FF_FMT_FLAG_* in internal.h.
607	*/
608	int flags_internal;
609
610	/**
611	* Tell if a given file has a chance of being parsed as this format.
612	* The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
613	* big so you do not have to check for that unless you need more.
614	*/
615	int (read_probe)(const* AVProbeData *);
616
617	/**
618	* Read the format header and initialize the AVFormatContext
619	* structure. Return 0 if OK. 'avformat_new_stream' should be
620	* called to create new streams.
621	*/
622	int (read_header)(struct* AVFormatContext *);
623
624	/**
625	* Read one packet and put it in 'pkt'. pts and flags are also
626	* set. 'avformat_new_stream' can be called only if the flag
627	* AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
628	* background thread).
629	* @return 0 on success, < 0 on error.
630	* Upon returning an error, pkt must be unreferenced by the caller.
631	*/
632	int (read_packet)(struct* AVFormatContext , AVPacket pkt);
633
634	/**
635	* Close the stream. The AVFormatContext and AVStreams are not
636	* freed by this function
637	*/
638	int (read_close)(struct* AVFormatContext *);
639
640	/**
641	* Seek to a given timestamp relative to the frames in
642	* stream component stream_index.
643	* @param stream_index Must not be -1.
644	* @param flags Selects which direction should be preferred if no exact
645	* match is available.
646	* @return >= 0 on success (but not necessarily the new offset)
647	*/
648	int (read_seek)(struct* AVFormatContext *,
649	int stream_index, int64_t timestamp, int flags);
650
651	/**
652	* Get the next timestamp in stream[stream_index].time_base units.
653	* @return the timestamp or AV_NOPTS_VALUE if an error occurred
654	*/
655	int64_t (read_timestamp)(struct* AVFormatContext s, int* stream_index,
656	int64_t *pos, int64_t pos_limit);
657
658	/**
659	* Start/resume playing - only meaningful if using a network-based format
660	* (RTSP).
661	*/
662	int (read_play)(struct* AVFormatContext *);
663
664	/**
665	* Pause playing - only meaningful if using a network-based format
666	* (RTSP).
667	*/
668	int (read_pause)(struct* AVFormatContext *);
669
670	/**
671	* Seek to timestamp ts.
672	* Seeking will be done so that the point from which all active streams
673	* can be presented successfully will be closest to ts and within min/max_ts.
674	* Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
675	*/
676	int (read_seek2)(struct* AVFormatContext s, int* stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
677
678	/**
679	* Returns device list with it properties.
680	* @see avdevice_list_devices() for more details.
681	*/
682	int (get_device_list)(struct* AVFormatContext s, struct* AVDeviceInfoList *device_list);
683
684	} AVInputFormat;
685	/**
686	* @}
687	*/
688
689	enum AVStreamParseType {
690	AVSTREAM_PARSE_NONE,
691	AVSTREAM_PARSE_FULL, /< full parsing and repack /*
692	AVSTREAM_PARSE_HEADERS, /< Only parse headers, do not repack. /*
693	AVSTREAM_PARSE_TIMESTAMPS, /< full parsing and interpolation of timestamps for frames not starting on a packet boundary /*
694	AVSTREAM_PARSE_FULL_ONCE, /< full parsing and repack of the first frame only, only implemented for H.264 currently /*
695	AVSTREAM_PARSE_FULL_RAW, /< full parsing and repack with timestamp and position generation by parser for raw
696	this assumes that each packet in the file contains no demuxer level headers and
697	just codec level data, otherwise position generation would fail /*
698	};
699
700	typedef struct AVIndexEntry {
701	int64_t pos;
702	int64_t timestamp; /<
703	* Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are available
704	* when seeking to this entry. That means preferable PTS on keyframe based formats.
705	* But demuxers can choose to store a different timestamp, if it is more convenient for the implementation or nothing better
706	* is known
707	*/
708	#define AVINDEX_KEYFRAME 0x0001
709	#define AVINDEX_DISCARD_FRAME 0x0002 /**
710	* Flag is used to indicate which frame should be discarded after decoding.
711	*/
712	int flags:`2`;
713	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).
714	int min_distance; /< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. /*
715	} AVIndexEntry;
716
717	/**
718	* The stream should be chosen by default among other streams of the same type,
719	* unless the user has explicitly specified otherwise.
720	*/
721	#define AV_DISPOSITION_DEFAULT (1 << 0)
722	/**
723	* The stream is not in original language.
724	*
725	* @note AV_DISPOSITION_ORIGINAL is the inverse of this disposition. At most
726	* one of them should be set in properly tagged streams.
727	* @note This disposition may apply to any stream type, not just audio.
728	*/
729	#define AV_DISPOSITION_DUB (1 << 1)
730	/**
731	* The stream is in original language.
732	*
733	* @see the notes for AV_DISPOSITION_DUB
734	*/
735	#define AV_DISPOSITION_ORIGINAL (1 << 2)
736	/**
737	* The stream is a commentary track.
738	*/
739	#define AV_DISPOSITION_COMMENT (1 << 3)
740	/**
741	* The stream contains song lyrics.
742	*/
743	#define AV_DISPOSITION_LYRICS (1 << 4)
744	/**
745	* The stream contains karaoke audio.
746	*/
747	#define AV_DISPOSITION_KARAOKE (1 << 5)
748
749	/**
750	* Track should be used during playback by default.
751	* Useful for subtitle track that should be displayed
752	* even when user did not explicitly ask for subtitles.
753	*/
754	#define AV_DISPOSITION_FORCED (1 << 6)
755	/**
756	* The stream is intended for hearing impaired audiences.
757	*/
758	#define AV_DISPOSITION_HEARING_IMPAIRED (1 << 7)
759	/**
760	* The stream is intended for visually impaired audiences.
761	*/
762	#define AV_DISPOSITION_VISUAL_IMPAIRED (1 << 8)
763	/**
764	* The audio stream contains music and sound effects without voice.
765	*/
766	#define AV_DISPOSITION_CLEAN_EFFECTS (1 << 9)
767	/**
768	* The stream is stored in the file as an attached picture/"cover art" (e.g.
769	* APIC frame in ID3v2). The first (usually only) packet associated with it
770	* will be returned among the first few packets read from the file unless
771	* seeking takes place. It can also be accessed at any time in
772	* AVStream.attached_pic.
773	*/
774	#define AV_DISPOSITION_ATTACHED_PIC (1 << 10)
775	/**
776	* The stream is sparse, and contains thumbnail images, often corresponding
777	* to chapter markers. Only ever used with AV_DISPOSITION_ATTACHED_PIC.
778	*/
779	#define AV_DISPOSITION_TIMED_THUMBNAILS (1 << 11)
780
781	/**
782	* The stream is intended to be mixed with a spatial audio track. For example,
783	* it could be used for narration or stereo music, and may remain unchanged by
784	* listener head rotation.
785	*/
786	#define AV_DISPOSITION_NON_DIEGETIC (1 << 12)
787
788	/**
789	* The subtitle stream contains captions, providing a transcription and possibly
790	* a translation of audio. Typically intended for hearing-impaired audiences.
791	*/
792	#define AV_DISPOSITION_CAPTIONS (1 << 16)
793	/**
794	* The subtitle stream contains a textual description of the video content.
795	* Typically intended for visually-impaired audiences or for the cases where the
796	* video cannot be seen.
797	*/
798	#define AV_DISPOSITION_DESCRIPTIONS (1 << 17)
799	/**
800	* The subtitle stream contains time-aligned metadata that is not intended to be
801	* directly presented to the user.
802	*/
803	#define AV_DISPOSITION_METADATA (1 << 18)
804	/**
805	* The audio stream is intended to be mixed with another stream before
806	* presentation.
807	* Corresponds to mix_type=0 in mpegts.
808	*/
809	#define AV_DISPOSITION_DEPENDENT (1 << 19)
810	/**
811	* The video stream contains still images.
812	*/
813	#define AV_DISPOSITION_STILL_IMAGE (1 << 20)
814
815	/**
816	* @return The AV_DISPOSITION_* flag corresponding to disp or a negative error
817	* code if disp does not correspond to a known stream disposition.
818	*/
819	int av_disposition_from_string(const char *disp);
820
821	/**
822	* @param disposition a combination of AV_DISPOSITION_* values
823	* @return The string description corresponding to the lowest set bit in
824	* disposition. NULL when the lowest set bit does not correspond
825	* to a known disposition or when disposition is 0.
826	*/
827	const char av_disposition_to_string(int* disposition);
828
829	/**
830	* Options for behavior on timestamp wrap detection.
831	*/
832	#define AV_PTS_WRAP_IGNORE 0 ///< ignore the wrap
833	#define AV_PTS_WRAP_ADD_OFFSET 1 ///< add the format specific offset on wrap detection
834	#define AV_PTS_WRAP_SUB_OFFSET -1 ///< subtract the format specific offset on wrap detection
835
836	/**
837	* Stream structure.
838	* New fields can be added to the end with minor version bumps.
839	* Removal, reordering and changes to existing fields require a major
840	* version bump.
841	* sizeof(AVStream) must not be used outside libav*.
842	*/
843	typedef struct AVStream {
844	/**
845	* A class for @ref avoptions. Set on stream creation.
846	*/
847	const AVClass *av_class;
848
849	int index; /< stream index in AVFormatContext /*
850	/**
851	* Format-specific stream ID.
852	* decoding: set by libavformat
853	* encoding: set by the user, replaced by libavformat if left unset
854	*/
855	int id;
856
857	/**
858	* Codec parameters associated with this stream. Allocated and freed by
859	* libavformat in avformat_new_stream() and avformat_free_context()
860	* respectively.
861	*
862	* - demuxing: filled by libavformat on stream creation or in
863	* avformat_find_stream_info()
864	* - muxing: filled by the caller before avformat_write_header()
865	*/
866	AVCodecParameters *codecpar;
867
868	void *priv_data;
869
870	/**
871	* This is the fundamental unit of time (in seconds) in terms
872	* of which frame timestamps are represented.
873	*
874	* decoding: set by libavformat
875	* encoding: May be set by the caller before avformat_write_header() to
876	* provide a hint to the muxer about the desired timebase. In
877	* avformat_write_header(), the muxer will overwrite this field
878	* with the timebase that will actually be used for the timestamps
879	* written into the file (which may or may not be related to the
880	* user-provided one, depending on the format).
881	*/
882	AVRational time_base;
883
884	/**
885	* Decoding: pts of the first frame of the stream in presentation order, in stream time base.
886	* Only set this if you are absolutely 100% sure that the value you set
887	* it to really is the pts of the first frame.
888	* This may be undefined (AV_NOPTS_VALUE).
889	* @note The ASF header does NOT contain a correct start_time the ASF
890	* demuxer must NOT set this.
891	*/
892	int64_t start_time;
893
894	/**
895	* Decoding: duration of the stream, in stream time base.
896	* If a source file does not specify a duration, but does specify
897	* a bitrate, this value will be estimated from bitrate and file size.
898	*
899	* Encoding: May be set by the caller before avformat_write_header() to
900	* provide a hint to the muxer about the estimated duration.
901	*/
902	int64_t duration;
903
904	int64_t nb_frames; ///< number of frames in this stream if known or 0
905
906	/**
907	* Stream disposition - a combination of AV_DISPOSITION_* flags.
908	* - demuxing: set by libavformat when creating the stream or in
909	* avformat_find_stream_info().
910	* - muxing: may be set by the caller before avformat_write_header().
911	*/
912	int disposition;
913
914	enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
915
916	/**
917	* sample aspect ratio (0 if unknown)
918	* - encoding: Set by user.
919	* - decoding: Set by libavformat.
920	*/
921	AVRational sample_aspect_ratio;
922
923	AVDictionary *metadata;
924
925	/**
926	* Average framerate
927	*
928	* - demuxing: May be set by libavformat when creating the stream or in
929	* avformat_find_stream_info().
930	* - muxing: May be set by the caller before avformat_write_header().
931	*/
932	AVRational avg_frame_rate;
933
934	/**
935	* For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
936	* will contain the attached picture.
937	*
938	* decoding: set by libavformat, must not be modified by the caller.
939	* encoding: unused
940	*/
941	AVPacket attached_pic;
942
943	#if FF_API_AVSTREAM_SIDE_DATA
944	/**
945	* An array of side data that applies to the whole stream (i.e. the
946	* container does not allow it to change between packets).
947	*
948	* There may be no overlap between the side data in this array and side data
949	* in the packets. I.e. a given side data is either exported by the muxer
950	* (demuxing) / set by the caller (muxing) in this array, then it never
951	* appears in the packets, or the side data is exported / sent through
952	* the packets (always in the first packet where the value becomes known or
953	* changes), then it does not appear in this array.
954	*
955	* - demuxing: Set by libavformat when the stream is created.
956	* - muxing: May be set by the caller before avformat_write_header().
957	*
958	* Freed by libavformat in avformat_free_context().
959	*
960	* @deprecated use AVStream's @ref AVCodecParameters.coded_side_data
961	* "codecpar side data".
962	*/
963	attribute_deprecated
964	AVPacketSideData *side_data;
965	/**
966	* The number of elements in the AVStream.side_data array.
967	*
968	* @deprecated use AVStream's @ref AVCodecParameters.nb_coded_side_data
969	* "codecpar side data".
970	*/
971	attribute_deprecated
972	int nb_side_data;
973	#endif
974
975	/**
976	* Flags indicating events happening on the stream, a combination of
977	* AVSTREAM_EVENT_FLAG_*.
978	*
979	* - demuxing: may be set by the demuxer in avformat_open_input(),
980	* avformat_find_stream_info() and av_read_frame(). Flags must be cleared
981	* by the user once the event has been handled.
982	* - muxing: may be set by the user after avformat_write_header(). to
983	* indicate a user-triggered event. The muxer will clear the flags for
984	* events it has handled in av_[interleaved]_write_frame().
985	*/
986	int event_flags;
987	/**
988	* - demuxing: the demuxer read new metadata from the file and updated
989	* AVStream.metadata accordingly
990	* - muxing: the user updated AVStream.metadata and wishes the muxer to write
991	* it into the file
992	*/
993	#define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001
994	/**
995	* - demuxing: new packets for this stream were read from the file. This
996	* event is informational only and does not guarantee that new packets
997	* for this stream will necessarily be returned from av_read_frame().
998	*/
999	#define AVSTREAM_EVENT_FLAG_NEW_PACKETS (1 << 1)
1000
1001	/**
1002	* Real base framerate of the stream.
1003	* This is the lowest framerate with which all timestamps can be
1004	* represented accurately (it is the least common multiple of all
1005	* framerates in the stream). Note, this value is just a guess!
1006	* For example, if the time base is 1/90000 and all frames have either
1007	* approximately 3600 or 1800 timer ticks, then r_frame_rate will be 50/1.
1008	*/
1009	AVRational r_frame_rate;
1010
1011	/**
1012	* Number of bits in timestamps. Used for wrapping control.
1013	*
1014	* - demuxing: set by libavformat
1015	* - muxing: set by libavformat
1016	*
1017	*/
1018	int pts_wrap_bits;
1019	} AVStream;
1020
1021	struct AVCodecParserContext av_stream_get_parser(const* AVStream *s);
1022
1023	#if FF_API_GET_END_PTS
1024	/**
1025	* Returns the pts of the last muxed packet + its duration
1026	*
1027	* the retuned value is undefined when used with a demuxer.
1028	*/
1029	attribute_deprecated
1030	int64_t av_stream_get_end_pts(const AVStream *st);
1031	#endif
1032
1033	// Chromium: We use the internal field first_dts vvv
1034	int64_t av_stream_get_first_dts(const AVStream *st);
1035	// Chromium: We use the internal field first_dts ^^^
1036
1037	#define AV_PROGRAM_RUNNING 1
1038
1039	/**
1040	* New fields can be added to the end with minor version bumps.
1041	* Removal, reordering and changes to existing fields require a major
1042	* version bump.
1043	* sizeof(AVProgram) must not be used outside libav*.
1044	*/
1045	typedef struct AVProgram {
1046	int id;
1047	int flags;
1048	enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
1049	unsigned int *stream_index;
1050	unsigned int nb_stream_indexes;
1051	AVDictionary *metadata;
1052
1053	int program_num;
1054	int pmt_pid;
1055	int pcr_pid;
1056	int pmt_version;
1057
1058	/*****************************************************************
1059	* All fields below this line are not part of the public API. They
1060	* may not be used outside of libavformat and can be changed and
1061	* removed at will.
1062	* New public fields should be added right above.
1063	*****************************************************************
1064	*/
1065	int64_t start_time;
1066	int64_t end_time;
1067
1068	int64_t pts_wrap_reference; ///< reference dts for wrap detection
1069	int pts_wrap_behavior; ///< behavior on wrap detection
1070	} AVProgram;
1071
1072	#define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
1073	(streams are added dynamically) */
1074	#define AVFMTCTX_UNSEEKABLE 0x0002 /**< signal that the stream is definitely
1075	not seekable, and attempts to call the
1076	seek function will fail. For some
1077	network protocols (e.g. HLS), this can
1078	change dynamically at runtime. */
1079
1080	typedef struct AVChapter {
1081	int64_t id; ///< unique ID to identify the chapter
1082	AVRational time_base; ///< time base in which the start/end timestamps are specified
1083	int64_t start, end; ///< chapter start/end time in time_base units
1084	AVDictionary *metadata;
1085	} AVChapter;
1086
1087
1088	/**
1089	* Callback used by devices to communicate with application.
1090	*/
1091	typedef int (av_format_control_message)(struct* AVFormatContext s, int* type,
1092	void *data, size_t data_size);
1093
1094	typedef int (AVOpenCallback)(struct* AVFormatContext s, AVIOContext pb, const* char url, int* flags,
1095	const AVIOInterruptCB int_cb, AVDictionary *options);
1096
1097	/**
1098	* The duration of a video can be estimated through various ways, and this enum can be used
1099	* to know how the duration was estimated.
1100	*/
1101	enum AVDurationEstimationMethod {
1102	AVFMT_DURATION_FROM_PTS, ///< Duration accurately estimated from PTSes
1103	AVFMT_DURATION_FROM_STREAM, ///< Duration estimated from a stream with a known duration
1104	AVFMT_DURATION_FROM_BITRATE ///< Duration estimated from bitrate (less accurate)
1105	};
1106
1107	/**
1108	* Format I/O context.
1109	* New fields can be added to the end with minor version bumps.
1110	* Removal, reordering and changes to existing fields require a major
1111	* version bump.
1112	* sizeof(AVFormatContext) must not be used outside libav*, use
1113	* avformat_alloc_context() to create an AVFormatContext.
1114	*
1115	* Fields can be accessed through AVOptions (av_opt*),
1116	* the name string used matches the associated command line parameter name and
1117	* can be found in libavformat/options_table.h.
1118	* The AVOption/command line parameter names differ in some cases from the C
1119	* structure field names for historic reasons or brevity.
1120	*/
1121	typedef struct AVFormatContext {
1122	/**
1123	* A class for logging and @ref avoptions. Set by avformat_alloc_context().
1124	* Exports (de)muxer private options if they exist.
1125	*/
1126	const AVClass *av_class;
1127
1128	/**
1129	* The input container format.
1130	*
1131	* Demuxing only, set by avformat_open_input().
1132	*/
1133	const struct AVInputFormat *iformat;
1134
1135	/**
1136	* The output container format.
1137	*
1138	* Muxing only, must be set by the caller before avformat_write_header().
1139	*/
1140	const struct AVOutputFormat *oformat;
1141
1142	/**
1143	* Format private data. This is an AVOptions-enabled struct
1144	* if and only if iformat/oformat.priv_class is not NULL.
1145	*
1146	* - muxing: set by avformat_write_header()
1147	* - demuxing: set by avformat_open_input()
1148	*/
1149	void *priv_data;
1150
1151	/**
1152	* I/O context.
1153	*
1154	* - demuxing: either set by the user before avformat_open_input() (then
1155	* the user must close it manually) or set by avformat_open_input().
1156	* - muxing: set by the user before avformat_write_header(). The caller must
1157	* take care of closing / freeing the IO context.
1158	*
1159	* Do NOT set this field if AVFMT_NOFILE flag is set in
1160	* iformat/oformat.flags. In such a case, the (de)muxer will handle
1161	* I/O in some other way and this field will be NULL.
1162	*/
1163	AVIOContext *pb;
1164
1165	/ stream info /
1166	/**
1167	* Flags signalling stream properties. A combination of AVFMTCTX_*.
1168	* Set by libavformat.
1169	*/
1170	int ctx_flags;
1171
1172	/**
1173	* Number of elements in AVFormatContext.streams.
1174	*
1175	* Set by avformat_new_stream(), must not be modified by any other code.
1176	*/
1177	unsigned int nb_streams;
1178	/**
1179	* A list of all streams in the file. New streams are created with
1180	* avformat_new_stream().
1181	*
1182	* - demuxing: streams are created by libavformat in avformat_open_input().
1183	* If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
1184	* appear in av_read_frame().
1185	* - muxing: streams are created by the user before avformat_write_header().
1186	*
1187	* Freed by libavformat in avformat_free_context().
1188	*/
1189	AVStream **streams;
1190
1191	/**
1192	* input or output URL. Unlike the old filename field, this field has no
1193	* length restriction.
1194	*
1195	* - demuxing: set by avformat_open_input(), initialized to an empty
1196	* string if url parameter was NULL in avformat_open_input().
1197	* - muxing: may be set by the caller before calling avformat_write_header()
1198	* (or avformat_init_output() if that is called first) to a string
1199	* which is freeable by av_free(). Set to an empty string if it
1200	* was NULL in avformat_init_output().
1201	*
1202	* Freed by libavformat in avformat_free_context().
1203	*/
1204	char *url;
1205
1206	/**
1207	* Position of the first frame of the component, in
1208	* AV_TIME_BASE fractional seconds. NEVER set this value directly:
1209	* It is deduced from the AVStream values.
1210	*
1211	* Demuxing only, set by libavformat.
1212	*/
1213	int64_t start_time;
1214
1215	/**
1216	* Duration of the stream, in AV_TIME_BASE fractional
1217	* seconds. Only set this value if you know none of the individual stream
1218	* durations and also do not set any of them. This is deduced from the
1219	* AVStream values if not set.
1220	*
1221	* Demuxing only, set by libavformat.
1222	*/
1223	int64_t duration;
1224
1225	/**
1226	* Total stream bitrate in bit/s, 0 if not
1227	* available. Never set it directly if the file_size and the
1228	* duration are known as FFmpeg can compute it automatically.
1229	*/
1230	int64_t bit_rate;
1231
1232	unsigned int packet_size;
1233	int max_delay;
1234
1235	/**
1236	* Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
1237	* Set by the user before avformat_open_input() / avformat_write_header().
1238	*/
1239	int flags;
1240	#define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
1241	#define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
1242	#define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
1243	#define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
1244	#define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container
1245	#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
1246	#define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
1247	#define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
1248	#define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
1249	#define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
1250	/**
1251	* When muxing, try to avoid writing any random/volatile data to the output.
1252	* This includes any random IDs, real-time timestamps/dates, muxer version, etc.
1253	*
1254	* This flag is mainly intended for testing.
1255	*/
1256	#define AVFMT_FLAG_BITEXACT 0x0400
1257	#define AVFMT_FLAG_SORT_DTS 0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
1258	#define AVFMT_FLAG_FAST_SEEK 0x80000 ///< Enable fast, but inaccurate seeks for some formats
1259	#if FF_API_LAVF_SHORTEST
1260	#define AVFMT_FLAG_SHORTEST 0x100000 ///< Stop muxing when the shortest stream stops.
1261	#endif
1262	#define AVFMT_FLAG_AUTO_BSF 0x200000 ///< Add bitstream filters as requested by the muxer
1263
1264	/**
1265	* Maximum number of bytes read from input in order to determine stream
1266	* properties. Used when reading the global header and in
1267	* avformat_find_stream_info().
1268	*
1269	* Demuxing only, set by the caller before avformat_open_input().
1270	*
1271	* @note this is \e not used for determining the \ref AVInputFormat
1272	* "input format"
1273	* @sa format_probesize
1274	*/
1275	int64_t probesize;
1276
1277	/**
1278	* Maximum duration (in AV_TIME_BASE units) of the data read
1279	* from input in avformat_find_stream_info().
1280	* Demuxing only, set by the caller before avformat_find_stream_info().
1281	* Can be set to 0 to let avformat choose using a heuristic.
1282	*/
1283	int64_t max_analyze_duration;
1284
1285	const uint8_t *key;
1286	int keylen;
1287
1288	unsigned int nb_programs;
1289	AVProgram **programs;
1290
1291	/**
1292	* Forced video codec_id.
1293	* Demuxing: Set by user.
1294	*/
1295	enum AVCodecID video_codec_id;
1296
1297	/**
1298	* Forced audio codec_id.
1299	* Demuxing: Set by user.
1300	*/
1301	enum AVCodecID audio_codec_id;
1302
1303	/**
1304	* Forced subtitle codec_id.
1305	* Demuxing: Set by user.
1306	*/
1307	enum AVCodecID subtitle_codec_id;
1308
1309	/**
1310	* Maximum amount of memory in bytes to use for the index of each stream.
1311	* If the index exceeds this size, entries will be discarded as
1312	* needed to maintain a smaller size. This can lead to slower or less
1313	* accurate seeking (depends on demuxer).
1314	* Demuxers for which a full in-memory index is mandatory will ignore
1315	* this.
1316	* - muxing: unused
1317	* - demuxing: set by user
1318	*/
1319	unsigned int max_index_size;
1320
1321	/**
1322	* Maximum amount of memory in bytes to use for buffering frames
1323	* obtained from realtime capture devices.
1324	*/
1325	unsigned int max_picture_buffer;
1326
1327	/**
1328	* Number of chapters in AVChapter array.
1329	* When muxing, chapters are normally written in the file header,
1330	* so nb_chapters should normally be initialized before write_header
1331	* is called. Some muxers (e.g. mov and mkv) can also write chapters
1332	* in the trailer. To write chapters in the trailer, nb_chapters
1333	* must be zero when write_header is called and non-zero when
1334	* write_trailer is called.
1335	* - muxing: set by user
1336	* - demuxing: set by libavformat
1337	*/
1338	unsigned int nb_chapters;
1339	AVChapter **chapters;
1340
1341	/**
1342	* Metadata that applies to the whole file.
1343	*
1344	* - demuxing: set by libavformat in avformat_open_input()
1345	* - muxing: may be set by the caller before avformat_write_header()
1346	*
1347	* Freed by libavformat in avformat_free_context().
1348	*/
1349	AVDictionary *metadata;
1350
1351	/**
1352	* Start time of the stream in real world time, in microseconds
1353	* since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1354	* stream was captured at this real world time.
1355	* - muxing: Set by the caller before avformat_write_header(). If set to
1356	* either 0 or AV_NOPTS_VALUE, then the current wall-time will
1357	* be used.
1358	* - demuxing: Set by libavformat. AV_NOPTS_VALUE if unknown. Note that
1359	* the value may become known after some number of frames
1360	* have been received.
1361	*/
1362	int64_t start_time_realtime;
1363
1364	/**
1365	* The number of frames used for determining the framerate in
1366	* avformat_find_stream_info().
1367	* Demuxing only, set by the caller before avformat_find_stream_info().
1368	*/
1369	int fps_probe_size;
1370
1371	/**
1372	* Error recognition; higher values will detect more errors but may
1373	* misdetect some more or less valid parts as errors.
1374	* Demuxing only, set by the caller before avformat_open_input().
1375	*/
1376	int error_recognition;
1377
1378	/**
1379	* Custom interrupt callbacks for the I/O layer.
1380	*
1381	* demuxing: set by the user before avformat_open_input().
1382	* muxing: set by the user before avformat_write_header()
1383	* (mainly useful for AVFMT_NOFILE formats). The callback
1384	* should also be passed to avio_open2() if it's used to
1385	* open the file.
1386	*/
1387	AVIOInterruptCB interrupt_callback;
1388
1389	/**
1390	* Flags to enable debugging.
1391	*/
1392	int debug;
1393	#define FF_FDEBUG_TS 0x0001
1394
1395	/**
1396	* Maximum buffering duration for interleaving.
1397	*
1398	* To ensure all the streams are interleaved correctly,
1399	* av_interleaved_write_frame() will wait until it has at least one packet
1400	* for each stream before actually writing any packets to the output file.
1401	* When some streams are "sparse" (i.e. there are large gaps between
1402	* successive packets), this can result in excessive buffering.
1403	*
1404	* This field specifies the maximum difference between the timestamps of the
1405	* first and the last packet in the muxing queue, above which libavformat
1406	* will output a packet regardless of whether it has queued a packet for all
1407	* the streams.
1408	*
1409	* Muxing only, set by the caller before avformat_write_header().
1410	*/
1411	int64_t max_interleave_delta;
1412
1413	/**
1414	* Allow non-standard and experimental extension
1415	* @see AVCodecContext.strict_std_compliance
1416	*/
1417	int strict_std_compliance;
1418
1419	/**
1420	* Flags indicating events happening on the file, a combination of
1421	* AVFMT_EVENT_FLAG_*.
1422	*
1423	* - demuxing: may be set by the demuxer in avformat_open_input(),
1424	* avformat_find_stream_info() and av_read_frame(). Flags must be cleared
1425	* by the user once the event has been handled.
1426	* - muxing: may be set by the user after avformat_write_header() to
1427	* indicate a user-triggered event. The muxer will clear the flags for
1428	* events it has handled in av_[interleaved]_write_frame().
1429	*/
1430	int event_flags;
1431	/**
1432	* - demuxing: the demuxer read new metadata from the file and updated
1433	* AVFormatContext.metadata accordingly
1434	* - muxing: the user updated AVFormatContext.metadata and wishes the muxer to
1435	* write it into the file
1436	*/
1437	#define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001
1438
1439	/**
1440	* Maximum number of packets to read while waiting for the first timestamp.
1441	* Decoding only.
1442	*/
1443	int max_ts_probe;
1444
1445	/**
1446	* Avoid negative timestamps during muxing.
1447	* Any value of the AVFMT_AVOID_NEG_TS_* constants.
1448	* Note, this works better when using av_interleaved_write_frame().
1449	* - muxing: Set by user
1450	* - demuxing: unused
1451	*/
1452	int avoid_negative_ts;
1453	#define AVFMT_AVOID_NEG_TS_AUTO -1 ///< Enabled when required by target format
1454	#define AVFMT_AVOID_NEG_TS_DISABLED 0 ///< Do not shift timestamps even when they are negative.
1455	#define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
1456	#define AVFMT_AVOID_NEG_TS_MAKE_ZERO 2 ///< Shift timestamps so that they start at 0
1457
1458	/**
1459	* Transport stream id.
1460	* This will be moved into demuxer private options. Thus no API/ABI compatibility
1461	*/
1462	int ts_id;
1463
1464	/**
1465	* Audio preload in microseconds.
1466	* Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1467	* - encoding: Set by user
1468	* - decoding: unused
1469	*/
1470	int audio_preload;
1471
1472	/**
1473	* Max chunk time in microseconds.
1474	* Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1475	* - encoding: Set by user
1476	* - decoding: unused
1477	*/
1478	int max_chunk_duration;
1479
1480	/**
1481	* Max chunk size in bytes
1482	* Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1483	* - encoding: Set by user
1484	* - decoding: unused
1485	*/
1486	int max_chunk_size;
1487
1488	/**
1489	* forces the use of wallclock timestamps as pts/dts of packets
1490	* This has undefined results in the presence of B frames.
1491	* - encoding: unused
1492	* - decoding: Set by user
1493	*/
1494	int use_wallclock_as_timestamps;
1495
1496	/**
1497	* avio flags, used to force AVIO_FLAG_DIRECT.
1498	* - encoding: unused
1499	* - decoding: Set by user
1500	*/
1501	int avio_flags;
1502
1503	/**
1504	* The duration field can be estimated through various ways, and this field can be used
1505	* to know how the duration was estimated.
1506	* - encoding: unused
1507	* - decoding: Read by user
1508	*/
1509	enum AVDurationEstimationMethod duration_estimation_method;
1510
1511	/**
1512	* Skip initial bytes when opening stream
1513	* - encoding: unused
1514	* - decoding: Set by user
1515	*/
1516	int64_t skip_initial_bytes;
1517
1518	/**
1519	* Correct single timestamp overflows
1520	* - encoding: unused
1521	* - decoding: Set by user
1522	*/
1523	unsigned int correct_ts_overflow;
1524
1525	/**
1526	* Force seeking to any (also non key) frames.
1527	* - encoding: unused
1528	* - decoding: Set by user
1529	*/
1530	int seek2any;
1531
1532	/**
1533	* Flush the I/O context after each packet.
1534	* - encoding: Set by user
1535	* - decoding: unused
1536	*/
1537	int flush_packets;
1538
1539	/**
1540	* format probing score.
1541	* The maximal score is AVPROBE_SCORE_MAX, its set when the demuxer probes
1542	* the format.
1543	* - encoding: unused
1544	* - decoding: set by avformat, read by user
1545	*/
1546	int probe_score;
1547
1548	/**
1549	* Maximum number of bytes read from input in order to identify the
1550	* \ref AVInputFormat "input format". Only used when the format is not set
1551	* explicitly by the caller.
1552	*
1553	* Demuxing only, set by the caller before avformat_open_input().
1554	*
1555	* @sa probesize
1556	*/
1557	int format_probesize;
1558
1559	/**
1560	* ',' separated list of allowed decoders.
1561	* If NULL then all are allowed
1562	* - encoding: unused
1563	* - decoding: set by user
1564	*/
1565	char *codec_whitelist;
1566
1567	/**
1568	* ',' separated list of allowed demuxers.
1569	* If NULL then all are allowed
1570	* - encoding: unused
1571	* - decoding: set by user
1572	*/
1573	char *format_whitelist;
1574
1575	/**
1576	* IO repositioned flag.
1577	* This is set by avformat when the underlaying IO context read pointer
1578	* is repositioned, for example when doing byte based seeking.
1579	* Demuxers can use the flag to detect such changes.
1580	*/
1581	int io_repositioned;
1582
1583	/**
1584	* Forced video codec.
1585	* This allows forcing a specific decoder, even when there are multiple with
1586	* the same codec_id.
1587	* Demuxing: Set by user
1588	*/
1589	const struct AVCodec *video_codec;
1590
1591	/**
1592	* Forced audio codec.
1593	* This allows forcing a specific decoder, even when there are multiple with
1594	* the same codec_id.
1595	* Demuxing: Set by user
1596	*/
1597	const struct AVCodec *audio_codec;
1598
1599	/**
1600	* Forced subtitle codec.
1601	* This allows forcing a specific decoder, even when there are multiple with
1602	* the same codec_id.
1603	* Demuxing: Set by user
1604	*/
1605	const struct AVCodec *subtitle_codec;
1606
1607	/**
1608	* Forced data codec.
1609	* This allows forcing a specific decoder, even when there are multiple with
1610	* the same codec_id.
1611	* Demuxing: Set by user
1612	*/
1613	const struct AVCodec *data_codec;
1614
1615	/**
1616	* Number of bytes to be written as padding in a metadata header.
1617	* Demuxing: Unused.
1618	* Muxing: Set by user via av_format_set_metadata_header_padding.
1619	*/
1620	int metadata_header_padding;
1621
1622	/**
1623	* User data.
1624	* This is a place for some private data of the user.
1625	*/
1626	void *opaque;
1627
1628	/**
1629	* Callback used by devices to communicate with application.
1630	*/
1631	av_format_control_message control_message_cb;
1632
1633	/**
1634	* Output timestamp offset, in microseconds.
1635	* Muxing: set by user
1636	*/
1637	int64_t output_ts_offset;
1638
1639	/**
1640	* dump format separator.
1641	* can be ", " or "\n " or anything else
1642	* - muxing: Set by user.
1643	* - demuxing: Set by user.
1644	*/
1645	uint8_t *dump_separator;
1646
1647	/**
1648	* Forced Data codec_id.
1649	* Demuxing: Set by user.
1650	*/
1651	enum AVCodecID data_codec_id;
1652
1653	/**
1654	* ',' separated list of allowed protocols.
1655	* - encoding: unused
1656	* - decoding: set by user
1657	*/
1658	char *protocol_whitelist;
1659
1660	/**
1661	* A callback for opening new IO streams.
1662	*
1663	* Whenever a muxer or a demuxer needs to open an IO stream (typically from
1664	* avformat_open_input() for demuxers, but for certain formats can happen at
1665	* other times as well), it will call this callback to obtain an IO context.
1666	*
1667	* @param s the format context
1668	* @param pb on success, the newly opened IO context should be returned here
1669	* @param url the url to open
1670	* @param flags a combination of AVIO_FLAG_*
1671	* @param options a dictionary of additional options, with the same
1672	* semantics as in avio_open2()
1673	* @return 0 on success, a negative AVERROR code on failure
1674	*
1675	* @note Certain muxers and demuxers do nesting, i.e. they open one or more
1676	* additional internal format contexts. Thus the AVFormatContext pointer
1677	* passed to this callback may be different from the one facing the caller.
1678	* It will, however, have the same 'opaque' field.
1679	*/
1680	int (io_open)(struct* AVFormatContext s, AVIOContext pb, const* char *url,
1681	int flags, AVDictionary **options);
1682
1683	#if FF_API_AVFORMAT_IO_CLOSE
1684	/**
1685	* A callback for closing the streams opened with AVFormatContext.io_open().
1686	*
1687	* @deprecated use io_close2
1688	*/
1689	attribute_deprecated
1690	void (io_close)(struct* AVFormatContext s, AVIOContext pb);
1691	#endif
1692
1693	/**
1694	* ',' separated list of disallowed protocols.
1695	* - encoding: unused
1696	* - decoding: set by user
1697	*/
1698	char *protocol_blacklist;
1699
1700	/**
1701	* The maximum number of streams.
1702	* - encoding: unused
1703	* - decoding: set by user
1704	*/
1705	int max_streams;
1706
1707	/**
1708	* Skip duration calcuation in estimate_timings_from_pts.
1709	* - encoding: unused
1710	* - decoding: set by user
1711	*/
1712	int skip_estimate_duration_from_pts;
1713
1714	/**
1715	* Maximum number of packets that can be probed
1716	* - encoding: unused
1717	* - decoding: set by user
1718	*/
1719	int max_probe_packets;
1720
1721	/**
1722	* A callback for closing the streams opened with AVFormatContext.io_open().
1723	*
1724	* Using this is preferred over io_close, because this can return an error.
1725	* Therefore this callback is used instead of io_close by the generic
1726	* libavformat code if io_close is NULL or the default.
1727	*
1728	* @param s the format context
1729	* @param pb IO context to be closed and freed
1730	* @return 0 on success, a negative AVERROR code on failure
1731	*/
1732	int (io_close2)(struct* AVFormatContext s, AVIOContext pb);
1733	} AVFormatContext;
1734
1735	/**
1736	* This function will cause global side data to be injected in the next packet
1737	* of each stream as well as after any subsequent seek.
1738	*
1739	* @note global side data is always available in every AVStream's
1740	* @ref AVCodecParameters.coded_side_data "codecpar side data" array, and
1741	* in a @ref AVCodecContext.coded_side_data "decoder's side data" array if
1742	* initialized with said stream's codecpar.
1743	* @see av_packet_side_data_get()
1744	*/
1745	void av_format_inject_global_side_data(AVFormatContext *s);
1746
1747	/**
1748	* Returns the method used to set ctx->duration.
1749	*
1750	* @return AVFMT_DURATION_FROM_PTS, AVFMT_DURATION_FROM_STREAM, or AVFMT_DURATION_FROM_BITRATE.
1751	*/
1752	enum AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext* ctx);
1753
1754	/**
1755	* @defgroup lavf_core Core functions
1756	* @ingroup libavf
1757	*
1758	* Functions for querying libavformat capabilities, allocating core structures,
1759	* etc.
1760	* @{
1761	*/
1762
1763	/**
1764	* Return the LIBAVFORMAT_VERSION_INT constant.
1765	*/
1766	unsigned avformat_version(void);
1767
1768	/**
1769	* Return the libavformat build-time configuration.
1770	*/
1771	const char avformat_configuration(void*);
1772
1773	/**
1774	* Return the libavformat license.
1775	*/
1776	const char avformat_license(void*);
1777
1778	/**
1779	* Do global initialization of network libraries. This is optional,
1780	* and not recommended anymore.
1781	*
1782	* This functions only exists to work around thread-safety issues
1783	* with older GnuTLS or OpenSSL libraries. If libavformat is linked
1784	* to newer versions of those libraries, or if you do not use them,
1785	* calling this function is unnecessary. Otherwise, you need to call
1786	* this function before any other threads using them are started.
1787	*
1788	* This function will be deprecated once support for older GnuTLS and
1789	* OpenSSL libraries is removed, and this function has no purpose
1790	* anymore.
1791	*/
1792	int avformat_network_init(void);
1793
1794	/**
1795	* Undo the initialization done by avformat_network_init. Call it only
1796	* once for each time you called avformat_network_init.
1797	*/
1798	int avformat_network_deinit(void);
1799
1800	/**
1801	* Iterate over all registered muxers.
1802	*
1803	* @param opaque a pointer where libavformat will store the iteration state. Must
1804	* point to NULL to start the iteration.
1805	*
1806	* @return the next registered muxer or NULL when the iteration is
1807	* finished
1808	*/
1809	const AVOutputFormat av_muxer_iterate(void* **opaque);
1810
1811	/**
1812	* Iterate over all registered demuxers.
1813	*
1814	* @param opaque a pointer where libavformat will store the iteration state.
1815	* Must point to NULL to start the iteration.
1816	*
1817	* @return the next registered demuxer or NULL when the iteration is
1818	* finished
1819	*/
1820	const AVInputFormat av_demuxer_iterate(void* **opaque);
1821
1822	/**
1823	* Allocate an AVFormatContext.
1824	* avformat_free_context() can be used to free the context and everything
1825	* allocated by the framework within it.
1826	*/
1827	AVFormatContext avformat_alloc_context(void*);
1828
1829	/**
1830	* Free an AVFormatContext and all its streams.
1831	* @param s context to free
1832	*/
1833	void avformat_free_context(AVFormatContext *s);
1834
1835	/**
1836	* Get the AVClass for AVFormatContext. It can be used in combination with
1837	* AV_OPT_SEARCH_FAKE_OBJ for examining options.
1838	*
1839	* @see av_opt_find().
1840	*/
1841	const AVClass avformat_get_class(void*);
1842
1843	/**
1844	* Get the AVClass for AVStream. It can be used in combination with
1845	* AV_OPT_SEARCH_FAKE_OBJ for examining options.
1846	*
1847	* @see av_opt_find().
1848	*/
1849	const AVClass av_stream_get_class(void*);
1850
1851	/**
1852	* Add a new stream to a media file.
1853	*
1854	* When demuxing, it is called by the demuxer in read_header(). If the
1855	* flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
1856	* be called in read_packet().
1857	*
1858	* When muxing, should be called by the user before avformat_write_header().
1859	*
1860	* User is required to call avformat_free_context() to clean up the allocation
1861	* by avformat_new_stream().
1862	*
1863	* @param s media file handle
1864	* @param c unused, does nothing
1865	*
1866	* @return newly created stream or NULL on error.
1867	*/
1868	AVStream avformat_new_stream(AVFormatContext s, const struct AVCodec *c);
1869
1870	#if FF_API_AVSTREAM_SIDE_DATA
1871	/**
1872	* Wrap an existing array as stream side data.
1873	*
1874	* @param st stream
1875	* @param type side information type
1876	* @param data the side data array. It must be allocated with the av_malloc()
1877	* family of functions. The ownership of the data is transferred to
1878	* st.
1879	* @param size side information size
1880	*
1881	* @return zero on success, a negative AVERROR code on failure. On failure,
1882	* the stream is unchanged and the data remains owned by the caller.
1883	* @deprecated use av_packet_side_data_add() with the stream's
1884	* @ref AVCodecParameters.coded_side_data "codecpar side data"
1885	*/
1886	attribute_deprecated
1887	int av_stream_add_side_data(AVStream st, enum* AVPacketSideDataType type,
1888	uint8_t *data, size_t size);
1889
1890	/**
1891	* Allocate new information from stream.
1892	*
1893	* @param stream stream
1894	* @param type desired side information type
1895	* @param size side information size
1896	*
1897	* @return pointer to fresh allocated data or NULL otherwise
1898	* @deprecated use av_packet_side_data_new() with the stream's
1899	* @ref AVCodecParameters.coded_side_data "codecpar side data"
1900	*/
1901	attribute_deprecated
1902	uint8_t av_stream_new_side_data(AVStream stream,
1903	enum AVPacketSideDataType type, size_t size);
1904	/**
1905	* Get side information from stream.
1906	*
1907	* @param stream stream
1908	* @param type desired side information type
1909	* @param size If supplied, *size will be set to the size of the side data
1910	* or to zero if the desired side data is not present.
1911	*
1912	* @return pointer to data if present or NULL otherwise
1913	* @deprecated use av_packet_side_data_get() with the stream's
1914	* @ref AVCodecParameters.coded_side_data "codecpar side data"
1915	*/
1916	attribute_deprecated
1917	uint8_t av_stream_get_side_data(const* AVStream *stream,
1918	enum AVPacketSideDataType type, size_t *size);
1919	#endif
1920
1921	AVProgram av_new_program(AVFormatContext s, int id);
1922
1923	/**
1924	* @}
1925	*/
1926
1927
1928	/**
1929	* Allocate an AVFormatContext for an output format.
1930	* avformat_free_context() can be used to free the context and
1931	* everything allocated by the framework within it.
1932	*
1933	* @param ctx pointee is set to the created format context,
1934	* or to NULL in case of failure
1935	* @param oformat format to use for allocating the context, if NULL
1936	* format_name and filename are used instead
1937	* @param format_name the name of output format to use for allocating the
1938	* context, if NULL filename is used instead
1939	* @param filename the name of the filename to use for allocating the
1940	* context, may be NULL
1941	*
1942	* @return >= 0 in case of success, a negative AVERROR code in case of
1943	* failure
1944	*/
1945	int avformat_alloc_output_context2(AVFormatContext *ctx, const* AVOutputFormat *oformat,
1946	const char format_name, const* char *filename);
1947
1948	/**
1949	* @addtogroup lavf_decoding
1950	* @{
1951	*/
1952
1953	/**
1954	* Find AVInputFormat based on the short name of the input format.
1955	*/
1956	const AVInputFormat av_find_input_format(const* char *short_name);
1957
1958	/**
1959	* Guess the file format.
1960	*
1961	* @param pd data to be probed
1962	* @param is_opened Whether the file is already opened; determines whether
1963	* demuxers with or without AVFMT_NOFILE are probed.
1964	*/
1965	const AVInputFormat av_probe_input_format(const* AVProbeData pd, int* is_opened);
1966
1967	/**
1968	* Guess the file format.
1969	*
1970	* @param pd data to be probed
1971	* @param is_opened Whether the file is already opened; determines whether
1972	* demuxers with or without AVFMT_NOFILE are probed.
1973	* @param score_max A probe score larger that this is required to accept a
1974	* detection, the variable is set to the actual detection
1975	* score afterwards.
1976	* If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
1977	* to retry with a larger probe buffer.
1978	*/
1979	const AVInputFormat av_probe_input_format2(const* AVProbeData *pd,
1980	int is_opened, int *score_max);
1981
1982	/**
1983	* Guess the file format.
1984	*
1985	* @param is_opened Whether the file is already opened; determines whether
1986	* demuxers with or without AVFMT_NOFILE are probed.
1987	* @param score_ret The score of the best detection.
1988	*/
1989	const AVInputFormat av_probe_input_format3(const* AVProbeData *pd,
1990	int is_opened, int *score_ret);
1991
1992	/**
1993	* Probe a bytestream to determine the input format. Each time a probe returns
1994	* with a score that is too low, the probe buffer size is increased and another
1995	* attempt is made. When the maximum probe size is reached, the input format
1996	* with the highest score is returned.
1997	*
1998	* @param pb the bytestream to probe
1999	* @param fmt the input format is put here
2000	* @param url the url of the stream
2001	* @param logctx the log context
2002	* @param offset the offset within the bytestream to probe from
2003	* @param max_probe_size the maximum probe buffer size (zero for default)
2004	*
2005	* @return the score in case of success, a negative value corresponding to an
2006	* the maximal score is AVPROBE_SCORE_MAX
2007	* AVERROR code otherwise
2008	*/
2009	int av_probe_input_buffer2(AVIOContext pb, const* AVInputFormat **fmt,
2010	const char url, void* *logctx,
2011	unsigned int offset, unsigned int max_probe_size);
2012
2013	/**
2014	* Like av_probe_input_buffer2() but returns 0 on success
2015	*/
2016	int av_probe_input_buffer(AVIOContext pb, const* AVInputFormat **fmt,
2017	const char url, void* *logctx,
2018	unsigned int offset, unsigned int max_probe_size);
2019
2020	/**
2021	* Open an input stream and read the header. The codecs are not opened.
2022	* The stream must be closed with avformat_close_input().
2023	*
2024	* @param ps Pointer to user-supplied AVFormatContext (allocated by
2025	* avformat_alloc_context). May be a pointer to NULL, in
2026	* which case an AVFormatContext is allocated by this
2027	* function and written into ps.
2028	* Note that a user-supplied AVFormatContext will be freed
2029	* on failure.
2030	* @param url URL of the stream to open.
2031	* @param fmt If non-NULL, this parameter forces a specific input format.
2032	* Otherwise the format is autodetected.
2033	* @param options A dictionary filled with AVFormatContext and demuxer-private
2034	* options.
2035	* On return this parameter will be destroyed and replaced with
2036	* a dict containing options that were not found. May be NULL.
2037	*
2038	* @return 0 on success, a negative AVERROR on failure.
2039	*
2040	* @note If you want to use custom IO, preallocate the format context and set its pb field.
2041	*/
2042	int avformat_open_input(AVFormatContext *ps, const* char *url,
2043	const AVInputFormat fmt, AVDictionary *options);
2044
2045	/**
2046	* Read packets of a media file to get stream information. This
2047	* is useful for file formats with no headers such as MPEG. This
2048	* function also computes the real framerate in case of MPEG-2 repeat
2049	* frame mode.
2050	* The logical file position is not changed by this function;
2051	* examined packets may be buffered for later processing.
2052	*
2053	* @param ic media file handle
2054	* @param options If non-NULL, an ic.nb_streams long array of pointers to
2055	* dictionaries, where i-th member contains options for
2056	* codec corresponding to i-th stream.
2057	* On return each dictionary will be filled with options that were not found.
2058	* @return >=0 if OK, AVERROR_xxx on error
2059	*
2060	* @note this function isn't guaranteed to open all the codecs, so
2061	* options being non-empty at return is a perfectly normal behavior.
2062	*
2063	* @todo Let the user decide somehow what information is needed so that
2064	* we do not waste time getting stuff the user does not need.
2065	*/
2066	int avformat_find_stream_info(AVFormatContext ic, AVDictionary *options);
2067
2068	/**
2069	* Find the programs which belong to a given stream.
2070	*
2071	* @param ic media file handle
2072	* @param last the last found program, the search will start after this
2073	* program, or from the beginning if it is NULL
2074	* @param s stream index
2075	*
2076	* @return the next program which belongs to s, NULL if no program is found or
2077	* the last program is not among the programs of ic.
2078	*/
2079	AVProgram av_find_program_from_stream(AVFormatContext ic, AVProgram last, int* s);
2080
2081	void av_program_add_stream_index(AVFormatContext ac, int* progid, unsigned int idx);
2082
2083	/**
2084	* Find the "best" stream in the file.
2085	* The best stream is determined according to various heuristics as the most
2086	* likely to be what the user expects.
2087	* If the decoder parameter is non-NULL, av_find_best_stream will find the
2088	* default decoder for the stream's codec; streams for which no decoder can
2089	* be found are ignored.
2090	*
2091	* @param ic media file handle
2092	* @param type stream type: video, audio, subtitles, etc.
2093	* @param wanted_stream_nb user-requested stream number,
2094	* or -1 for automatic selection
2095	* @param related_stream try to find a stream related (eg. in the same
2096	* program) to this one, or -1 if none
2097	* @param decoder_ret if non-NULL, returns the decoder for the
2098	* selected stream
2099	* @param flags flags; none are currently defined
2100	*
2101	* @return the non-negative stream number in case of success,
2102	* AVERROR_STREAM_NOT_FOUND if no stream with the requested type
2103	* could be found,
2104	* AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
2105	*
2106	* @note If av_find_best_stream returns successfully and decoder_ret is not
2107	* NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
2108	*/
2109	int av_find_best_stream(AVFormatContext *ic,
2110	enum AVMediaType type,
2111	int wanted_stream_nb,
2112	int related_stream,
2113	const struct AVCodec **decoder_ret,
2114	int flags);
2115
2116	/**
2117	* Return the next frame of a stream.
2118	* This function returns what is stored in the file, and does not validate
2119	* that what is there are valid frames for the decoder. It will split what is
2120	* stored in the file into frames and return one for each call. It will not
2121	* omit invalid data between valid frames so as to give the decoder the maximum
2122	* information possible for decoding.
2123	*
2124	* On success, the returned packet is reference-counted (pkt->buf is set) and
2125	* valid indefinitely. The packet must be freed with av_packet_unref() when
2126	* it is no longer needed. For video, the packet contains exactly one frame.
2127	* For audio, it contains an integer number of frames if each frame has
2128	* a known fixed size (e.g. PCM or ADPCM data). If the audio frames have
2129	* a variable size (e.g. MPEG audio), then it contains one frame.
2130	*
2131	* pkt->pts, pkt->dts and pkt->duration are always set to correct
2132	* values in AVStream.time_base units (and guessed if the format cannot
2133	* provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
2134	* has B-frames, so it is better to rely on pkt->dts if you do not
2135	* decompress the payload.
2136	*
2137	* @return 0 if OK, < 0 on error or end of file. On error, pkt will be blank
2138	* (as if it came from av_packet_alloc()).
2139	*
2140	* @note pkt will be initialized, so it may be uninitialized, but it must not
2141	* contain data that needs to be freed.
2142	*/
2143	int av_read_frame(AVFormatContext s, AVPacket pkt);
2144
2145	/**
2146	* Seek to the keyframe at timestamp.
2147	* 'timestamp' in 'stream_index'.
2148	*
2149	* @param s media file handle
2150	* @param stream_index If stream_index is (-1), a default stream is selected,
2151	* and timestamp is automatically converted from
2152	* AV_TIME_BASE units to the stream specific time_base.
2153	* @param timestamp Timestamp in AVStream.time_base units or, if no stream
2154	* is specified, in AV_TIME_BASE units.
2155	* @param flags flags which select direction and seeking mode
2156	*
2157	* @return >= 0 on success
2158	*/
2159	int av_seek_frame(AVFormatContext s, int* stream_index, int64_t timestamp,
2160	int flags);
2161
2162	/**
2163	* Seek to timestamp ts.
2164	* Seeking will be done so that the point from which all active streams
2165	* can be presented successfully will be closest to ts and within min/max_ts.
2166	* Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
2167	*
2168	* If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
2169	* are the file position (this may not be supported by all demuxers).
2170	* If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
2171	* in the stream with stream_index (this may not be supported by all demuxers).
2172	* Otherwise all timestamps are in units of the stream selected by stream_index
2173	* or if stream_index is -1, in AV_TIME_BASE units.
2174	* If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
2175	* keyframes (this may not be supported by all demuxers).
2176	* If flags contain AVSEEK_FLAG_BACKWARD, it is ignored.
2177	*
2178	* @param s media file handle
2179	* @param stream_index index of the stream which is used as time base reference
2180	* @param min_ts smallest acceptable timestamp
2181	* @param ts target timestamp
2182	* @param max_ts largest acceptable timestamp
2183	* @param flags flags
2184	* @return >=0 on success, error code otherwise
2185	*
2186	* @note This is part of the new seek API which is still under construction.
2187	*/
2188	int avformat_seek_file(AVFormatContext s, int* stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
2189
2190	/**
2191	* Discard all internally buffered data. This can be useful when dealing with
2192	* discontinuities in the byte stream. Generally works only with formats that
2193	* can resync. This includes headerless formats like MPEG-TS/TS but should also
2194	* work with NUT, Ogg and in a limited way AVI for example.
2195	*
2196	* The set of streams, the detected duration, stream parameters and codecs do
2197	* not change when calling this function. If you want a complete reset, it's
2198	* better to open a new AVFormatContext.
2199	*
2200	* This does not flush the AVIOContext (s->pb). If necessary, call
2201	* avio_flush(s->pb) before calling this function.
2202	*
2203	* @param s media file handle
2204	* @return >=0 on success, error code otherwise
2205	*/
2206	int avformat_flush(AVFormatContext *s);
2207
2208	/**
2209	* Start playing a network-based stream (e.g. RTSP stream) at the
2210	* current position.
2211	*/
2212	int av_read_play(AVFormatContext *s);
2213
2214	/**
2215	* Pause a network-based stream (e.g. RTSP stream).
2216	*
2217	* Use av_read_play() to resume it.
2218	*/
2219	int av_read_pause(AVFormatContext *s);
2220
2221	/**
2222	* Close an opened input AVFormatContext. Free it and all its contents
2223	* and set *s to NULL.
2224	*/
2225	void avformat_close_input(AVFormatContext **s);
2226	/**
2227	* @}
2228	*/
2229
2230	#define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
2231	#define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
2232	#define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
2233	#define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
2234
2235	/**
2236	* @addtogroup lavf_encoding
2237	* @{
2238	*/
2239
2240	#define AVSTREAM_INIT_IN_WRITE_HEADER 0 ///< stream parameters initialized in avformat_write_header
2241	#define AVSTREAM_INIT_IN_INIT_OUTPUT 1 ///< stream parameters initialized in avformat_init_output
2242
2243	/**
2244	* Allocate the stream private data and write the stream header to
2245	* an output media file.
2246	*
2247	* @param s Media file handle, must be allocated with
2248	* avformat_alloc_context().
2249	* Its \ref AVFormatContext.oformat "oformat" field must be set
2250	* to the desired output format;
2251	* Its \ref AVFormatContext.pb "pb" field must be set to an
2252	* already opened ::AVIOContext.
2253	* @param options An ::AVDictionary filled with AVFormatContext and
2254	* muxer-private options.
2255	* On return this parameter will be destroyed and replaced with
2256	* a dict containing options that were not found. May be NULL.
2257	*
2258	* @retval AVSTREAM_INIT_IN_WRITE_HEADER On success, if the codec had not already been
2259	* fully initialized in avformat_init_output().
2260	* @retval AVSTREAM_INIT_IN_INIT_OUTPUT On success, if the codec had already been fully
2261	* initialized in avformat_init_output().
2262	* @retval AVERROR A negative AVERROR on failure.
2263	*
2264	* @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_init_output.
2265	*/
2266	av_warn_unused_result
2267	int avformat_write_header(AVFormatContext s, AVDictionary *options);
2268
2269	/**
2270	* Allocate the stream private data and initialize the codec, but do not write the header.
2271	* May optionally be used before avformat_write_header() to initialize stream parameters
2272	* before actually writing the header.
2273	* If using this function, do not pass the same options to avformat_write_header().
2274	*
2275	* @param s Media file handle, must be allocated with
2276	* avformat_alloc_context().
2277	* Its \ref AVFormatContext.oformat "oformat" field must be set
2278	* to the desired output format;
2279	* Its \ref AVFormatContext.pb "pb" field must be set to an
2280	* already opened ::AVIOContext.
2281	* @param options An ::AVDictionary filled with AVFormatContext and
2282	* muxer-private options.
2283	* On return this parameter will be destroyed and replaced with
2284	* a dict containing options that were not found. May be NULL.
2285	*
2286	* @retval AVSTREAM_INIT_IN_WRITE_HEADER On success, if the codec requires
2287	* avformat_write_header to fully initialize.
2288	* @retval AVSTREAM_INIT_IN_INIT_OUTPUT On success, if the codec has been fully
2289	* initialized.
2290	* @retval AVERROR Anegative AVERROR on failure.
2291	*
2292	* @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_write_header.
2293	*/
2294	av_warn_unused_result
2295	int avformat_init_output(AVFormatContext s, AVDictionary *options);
2296
2297	/**
2298	* Write a packet to an output media file.
2299	*
2300	* This function passes the packet directly to the muxer, without any buffering
2301	* or reordering. The caller is responsible for correctly interleaving the
2302	* packets if the format requires it. Callers that want libavformat to handle
2303	* the interleaving should call av_interleaved_write_frame() instead of this
2304	* function.
2305	*
2306	* @param s media file handle
2307	* @param pkt The packet containing the data to be written. Note that unlike
2308	* av_interleaved_write_frame(), this function does not take
2309	* ownership of the packet passed to it (though some muxers may make
2310	* an internal reference to the input packet).
2311	* <br>
2312	* This parameter can be NULL (at any time, not just at the end), in
2313	* order to immediately flush data buffered within the muxer, for
2314	* muxers that buffer up data internally before writing it to the
2315	* output.
2316	* <br>
2317	* Packet's @ref AVPacket.stream_index "stream_index" field must be
2318	* set to the index of the corresponding stream in @ref
2319	* AVFormatContext.streams "s->streams".
2320	* <br>
2321	* The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2322	* must be set to correct values in the stream's timebase (unless the
2323	* output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2324	* they can be set to AV_NOPTS_VALUE).
2325	* The dts for subsequent packets passed to this function must be strictly
2326	* increasing when compared in their respective timebases (unless the
2327	* output format is flagged with the AVFMT_TS_NONSTRICT, then they
2328	* merely have to be nondecreasing). @ref AVPacket.duration
2329	* "duration") should also be set if known.
2330	* @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
2331	*
2332	* @see av_interleaved_write_frame()
2333	*/
2334	int av_write_frame(AVFormatContext s, AVPacket pkt);
2335
2336	/**
2337	* Write a packet to an output media file ensuring correct interleaving.
2338	*
2339	* This function will buffer the packets internally as needed to make sure the
2340	* packets in the output file are properly interleaved, usually ordered by
2341	* increasing dts. Callers doing their own interleaving should call
2342	* av_write_frame() instead of this function.
2343	*
2344	* Using this function instead of av_write_frame() can give muxers advance
2345	* knowledge of future packets, improving e.g. the behaviour of the mp4
2346	* muxer for VFR content in fragmenting mode.
2347	*
2348	* @param s media file handle
2349	* @param pkt The packet containing the data to be written.
2350	* <br>
2351	* If the packet is reference-counted, this function will take
2352	* ownership of this reference and unreference it later when it sees
2353	* fit. If the packet is not reference-counted, libavformat will
2354	* make a copy.
2355	* The returned packet will be blank (as if returned from
2356	* av_packet_alloc()), even on error.
2357	* <br>
2358	* This parameter can be NULL (at any time, not just at the end), to
2359	* flush the interleaving queues.
2360	* <br>
2361	* Packet's @ref AVPacket.stream_index "stream_index" field must be
2362	* set to the index of the corresponding stream in @ref
2363	* AVFormatContext.streams "s->streams".
2364	* <br>
2365	* The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2366	* must be set to correct values in the stream's timebase (unless the
2367	* output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2368	* they can be set to AV_NOPTS_VALUE).
2369	* The dts for subsequent packets in one stream must be strictly
2370	* increasing (unless the output format is flagged with the
2371	* AVFMT_TS_NONSTRICT, then they merely have to be nondecreasing).
2372	* @ref AVPacket.duration "duration" should also be set if known.
2373	*
2374	* @return 0 on success, a negative AVERROR on error.
2375	*
2376	* @see av_write_frame(), AVFormatContext.max_interleave_delta
2377	*/
2378	int av_interleaved_write_frame(AVFormatContext s, AVPacket pkt);
2379
2380	/**
2381	* Write an uncoded frame to an output media file.
2382	*
2383	* The frame must be correctly interleaved according to the container
2384	* specification; if not, av_interleaved_write_uncoded_frame() must be used.
2385	*
2386	* See av_interleaved_write_uncoded_frame() for details.
2387	*/
2388	int av_write_uncoded_frame(AVFormatContext s, int* stream_index,
2389	struct AVFrame *frame);
2390
2391	/**
2392	* Write an uncoded frame to an output media file.
2393	*
2394	* If the muxer supports it, this function makes it possible to write an AVFrame
2395	* structure directly, without encoding it into a packet.
2396	* It is mostly useful for devices and similar special muxers that use raw
2397	* video or PCM data and will not serialize it into a byte stream.
2398	*
2399	* To test whether it is possible to use it with a given muxer and stream,
2400	* use av_write_uncoded_frame_query().
2401	*
2402	* The caller gives up ownership of the frame and must not access it
2403	* afterwards.
2404	*
2405	* @return >=0 for success, a negative code on error
2406	*/
2407	int av_interleaved_write_uncoded_frame(AVFormatContext s, int* stream_index,
2408	struct AVFrame *frame);
2409
2410	/**
2411	* Test whether a muxer supports uncoded frame.
2412	*
2413	* @return >=0 if an uncoded frame can be written to that muxer and stream,
2414	* <0 if not
2415	*/
2416	int av_write_uncoded_frame_query(AVFormatContext s, int* stream_index);
2417
2418	/**
2419	* Write the stream trailer to an output media file and free the
2420	* file private data.
2421	*
2422	* May only be called after a successful call to avformat_write_header.
2423	*
2424	* @param s media file handle
2425	* @return 0 if OK, AVERROR_xxx on error
2426	*/
2427	int av_write_trailer(AVFormatContext *s);
2428
2429	/**
2430	* Return the output format in the list of registered output formats
2431	* which best matches the provided parameters, or return NULL if
2432	* there is no match.
2433	*
2434	* @param short_name if non-NULL checks if short_name matches with the
2435	* names of the registered formats
2436	* @param filename if non-NULL checks if filename terminates with the
2437	* extensions of the registered formats
2438	* @param mime_type if non-NULL checks if mime_type matches with the
2439	* MIME type of the registered formats
2440	*/
2441	const AVOutputFormat av_guess_format(const* char *short_name,
2442	const char *filename,
2443	const char *mime_type);
2444
2445	/**
2446	* Guess the codec ID based upon muxer and filename.
2447	*/
2448	enum AVCodecID av_guess_codec(const AVOutputFormat fmt, const* char *short_name,
2449	const char filename, const* char *mime_type,
2450	enum AVMediaType type);
2451
2452	/**
2453	* Get timing information for the data currently output.
2454	* The exact meaning of "currently output" depends on the format.
2455	* It is mostly relevant for devices that have an internal buffer and/or
2456	* work in real time.
2457	* @param s media file handle
2458	* @param stream stream in the media file
2459	* @param[out] dts DTS of the last packet output for the stream, in stream
2460	* time_base units
2461	* @param[out] wall absolute time when that packet whas output,
2462	* in microsecond
2463	* @retval 0 Success
2464	* @retval AVERROR(ENOSYS) The format does not support it
2465	*
2466	* @note Some formats or devices may not allow to measure dts and wall
2467	* atomically.
2468	*/
2469	int av_get_output_timestamp(struct AVFormatContext s, int* stream,
2470	int64_t dts, int64_t wall);
2471
2472
2473	/**
2474	* @}
2475	*/
2476
2477
2478	/**
2479	* @defgroup lavf_misc Utility functions
2480	* @ingroup libavf
2481	* @{
2482	*
2483	* Miscellaneous utility functions related to both muxing and demuxing
2484	* (or neither).
2485	*/
2486
2487	/**
2488	* Send a nice hexadecimal dump of a buffer to the specified file stream.
2489	*
2490	* @param f The file stream pointer where the dump should be sent to.
2491	* @param buf buffer
2492	* @param size buffer size
2493	*
2494	* @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
2495	*/
2496	void av_hex_dump(FILE f, const* uint8_t buf, int* size);
2497
2498	/**
2499	* Send a nice hexadecimal dump of a buffer to the log.
2500	*
2501	* @param avcl A pointer to an arbitrary struct of which the first field is a
2502	* pointer to an AVClass struct.
2503	* @param level The importance level of the message, lower values signifying
2504	* higher importance.
2505	* @param buf buffer
2506	* @param size buffer size
2507	*
2508	* @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
2509	*/
2510	void av_hex_dump_log(void avcl, int* level, const uint8_t buf, int* size);
2511
2512	/**
2513	* Send a nice dump of a packet to the specified file stream.
2514	*
2515	* @param f The file stream pointer where the dump should be sent to.
2516	* @param pkt packet to dump
2517	* @param dump_payload True if the payload must be displayed, too.
2518	* @param st AVStream that the packet belongs to
2519	*/
2520	void av_pkt_dump2(FILE f, const* AVPacket pkt, int* dump_payload, const AVStream *st);
2521
2522
2523	/**
2524	* Send a nice dump of a packet to the log.
2525	*
2526	* @param avcl A pointer to an arbitrary struct of which the first field is a
2527	* pointer to an AVClass struct.
2528	* @param level The importance level of the message, lower values signifying
2529	* higher importance.
2530	* @param pkt packet to dump
2531	* @param dump_payload True if the payload must be displayed, too.
2532	* @param st AVStream that the packet belongs to
2533	*/
2534	void av_pkt_dump_log2(void avcl, int* level, const AVPacket pkt, int* dump_payload,
2535	const AVStream *st);
2536
2537	/**
2538	* Get the AVCodecID for the given codec tag tag.
2539	* If no codec id is found returns AV_CODEC_ID_NONE.
2540	*
2541	* @param tags list of supported codec_id-codec_tag pairs, as stored
2542	* in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2543	* @param tag codec tag to match to a codec ID
2544	*/
2545	enum AVCodecID av_codec_get_id(const struct AVCodecTag * const tags, unsigned* int tag);
2546
2547	/**
2548	* Get the codec tag for the given codec id id.
2549	* If no codec tag is found returns 0.
2550	*
2551	* @param tags list of supported codec_id-codec_tag pairs, as stored
2552	* in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2553	* @param id codec ID to match to a codec tag
2554	*/
2555	unsigned int av_codec_get_tag(const struct AVCodecTag * const tags, enum* AVCodecID id);
2556
2557	/**
2558	* Get the codec tag for the given codec id.
2559	*
2560	* @param tags list of supported codec_id - codec_tag pairs, as stored
2561	* in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2562	* @param id codec id that should be searched for in the list
2563	* @param tag A pointer to the found tag
2564	* @return 0 if id was not found in tags, > 0 if it was found
2565	*/
2566	int av_codec_get_tag2(const struct AVCodecTag * const tags, enum* AVCodecID id,
2567	unsigned int *tag);
2568
2569	int av_find_default_stream_index(AVFormatContext *s);
2570
2571	/**
2572	* Get the index for a specific timestamp.
2573	*
2574	* @param st stream that the timestamp belongs to
2575	* @param timestamp timestamp to retrieve the index for
2576	* @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
2577	* to the timestamp which is <= the requested one, if backward
2578	* is 0, then it will be >=
2579	* if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
2580	* @return < 0 if no such timestamp could be found
2581	*/
2582	int av_index_search_timestamp(AVStream st, int64_t timestamp, int* flags);
2583
2584	/**
2585	* Get the index entry count for the given AVStream.
2586	*
2587	* @param st stream
2588	* @return the number of index entries in the stream
2589	*/
2590	int avformat_index_get_entries_count(const AVStream *st);
2591
2592	/**
2593	* Get the AVIndexEntry corresponding to the given index.
2594	*
2595	* @param st Stream containing the requested AVIndexEntry.
2596	* @param idx The desired index.
2597	* @return A pointer to the requested AVIndexEntry if it exists, NULL otherwise.
2598	*
2599	* @note The pointer returned by this function is only guaranteed to be valid
2600	* until any function that takes the stream or the parent AVFormatContext
2601	* as input argument is called.
2602	*/
2603	const AVIndexEntry avformat_index_get_entry(AVStream st, int idx);
2604
2605	/**
2606	* Get the AVIndexEntry corresponding to the given timestamp.
2607	*
2608	* @param st Stream containing the requested AVIndexEntry.
2609	* @param wanted_timestamp Timestamp to retrieve the index entry for.
2610	* @param flags If AVSEEK_FLAG_BACKWARD then the returned entry will correspond
2611	* to the timestamp which is <= the requested one, if backward
2612	* is 0, then it will be >=
2613	* if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise.
2614	* @return A pointer to the requested AVIndexEntry if it exists, NULL otherwise.
2615	*
2616	* @note The pointer returned by this function is only guaranteed to be valid
2617	* until any function that takes the stream or the parent AVFormatContext
2618	* as input argument is called.
2619	*/
2620	const AVIndexEntry avformat_index_get_entry_from_timestamp(AVStream st,
2621	int64_t wanted_timestamp,
2622	int flags);
2623	/**
2624	* Add an index entry into a sorted list. Update the entry if the list
2625	* already contains it.
2626	*
2627	* @param timestamp timestamp in the time base of the given stream
2628	*/
2629	int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
2630	int size, int distance, int flags);
2631
2632
2633	/**
2634	* Split a URL string into components.
2635	*
2636	* The pointers to buffers for storing individual components may be null,
2637	* in order to ignore that component. Buffers for components not found are
2638	* set to empty strings. If the port is not found, it is set to a negative
2639	* value.
2640	*
2641	* @param proto the buffer for the protocol
2642	* @param proto_size the size of the proto buffer
2643	* @param authorization the buffer for the authorization
2644	* @param authorization_size the size of the authorization buffer
2645	* @param hostname the buffer for the host name
2646	* @param hostname_size the size of the hostname buffer
2647	* @param port_ptr a pointer to store the port number in
2648	* @param path the buffer for the path
2649	* @param path_size the size of the path buffer
2650	* @param url the URL to split
2651	*/
2652	void av_url_split(char proto, int* proto_size,
2653	char authorization, int* authorization_size,
2654	char hostname, int* hostname_size,
2655	int *port_ptr,
2656	char path, int* path_size,
2657	const char *url);
2658
2659
2660	/**
2661	* Print detailed information about the input or output format, such as
2662	* duration, bitrate, streams, container, programs, metadata, side data,
2663	* codec and time base.
2664	*
2665	* @param ic the context to analyze
2666	* @param index index of the stream to dump information about
2667	* @param url the URL to print, such as source or destination file
2668	* @param is_output Select whether the specified context is an input(0) or output(1)
2669	*/
2670	void av_dump_format(AVFormatContext *ic,
2671	int index,
2672	const char *url,
2673	int is_output);
2674
2675
2676	#define AV_FRAME_FILENAME_FLAGS_MULTIPLE 1 ///< Allow multiple %d
2677
2678	/**
2679	* Return in 'buf' the path with '%d' replaced by a number.
2680	*
2681	* Also handles the '%0nd' format where 'n' is the total number
2682	* of digits and '%%'.
2683	*
2684	* @param buf destination buffer
2685	* @param buf_size destination buffer size
2686	* @param path numbered sequence string
2687	* @param number frame number
2688	* @param flags AV_FRAME_FILENAME_FLAGS_*
2689	* @return 0 if OK, -1 on format error
2690	*/
2691	int av_get_frame_filename2(char buf, int* buf_size,
2692	const char path, int* number, int flags);
2693
2694	int av_get_frame_filename(char buf, int* buf_size,
2695	const char path, int* number);
2696
2697	/**
2698	* Check whether filename actually is a numbered sequence generator.
2699	*
2700	* @param filename possible numbered sequence string
2701	* @return 1 if a valid numbered sequence string, 0 otherwise
2702	*/
2703	int av_filename_number_test(const char *filename);
2704
2705	/**
2706	* Generate an SDP for an RTP session.
2707	*
2708	* Note, this overwrites the id values of AVStreams in the muxer contexts
2709	* for getting unique dynamic payload types.
2710	*
2711	* @param ac array of AVFormatContexts describing the RTP streams. If the
2712	* array is composed by only one context, such context can contain
2713	* multiple AVStreams (one AVStream per RTP stream). Otherwise,
2714	* all the contexts in the array (an AVCodecContext per RTP stream)
2715	* must contain only one AVStream.
2716	* @param n_files number of AVCodecContexts contained in ac
2717	* @param buf buffer where the SDP will be stored (must be allocated by
2718	* the caller)
2719	* @param size the size of the buffer
2720	* @return 0 if OK, AVERROR_xxx on error
2721	*/
2722	int av_sdp_create(AVFormatContext ac[], int* n_files, char buf, int* size);
2723
2724	/**
2725	* Return a positive value if the given filename has one of the given
2726	* extensions, 0 otherwise.
2727	*
2728	* @param filename file name to check against the given extensions
2729	* @param extensions a comma-separated list of filename extensions
2730	*/
2731	int av_match_ext(const char filename, const* char *extensions);
2732
2733	/**
2734	* Test if the given container can store a codec.
2735	*
2736	* @param ofmt container to check for compatibility
2737	* @param codec_id codec to potentially store in container
2738	* @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
2739	*
2740	* @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
2741	* A negative number if this information is not available.
2742	*/
2743	int avformat_query_codec(const AVOutputFormat ofmt, enum* AVCodecID codec_id,
2744	int std_compliance);
2745
2746	/**
2747	* @defgroup riff_fourcc RIFF FourCCs
2748	* @{
2749	* Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
2750	* meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
2751	* following code:
2752	* @code
2753	* uint32_t tag = MKTAG('H', '2', '6', '4');
2754	* const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
2755	* enum AVCodecID id = av_codec_get_id(table, tag);
2756	* @endcode
2757	*/
2758	/**
2759	* @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
2760	*/
2761	const struct AVCodecTag avformat_get_riff_video_tags(void*);
2762	/**
2763	* @return the table mapping RIFF FourCCs for audio to AVCodecID.
2764	*/
2765	const struct AVCodecTag avformat_get_riff_audio_tags(void*);
2766	/**
2767	* @return the table mapping MOV FourCCs for video to libavcodec AVCodecID.
2768	*/
2769	const struct AVCodecTag avformat_get_mov_video_tags(void*);
2770	/**
2771	* @return the table mapping MOV FourCCs for audio to AVCodecID.
2772	*/
2773	const struct AVCodecTag avformat_get_mov_audio_tags(void*);
2774
2775	/**
2776	* @}
2777	*/
2778
2779	/**
2780	* Guess the sample aspect ratio of a frame, based on both the stream and the
2781	* frame aspect ratio.
2782	*
2783	* Since the frame aspect ratio is set by the codec but the stream aspect ratio
2784	* is set by the demuxer, these two may not be equal. This function tries to
2785	* return the value that you should use if you would like to display the frame.
2786	*
2787	* Basic logic is to use the stream aspect ratio if it is set to something sane
2788	* otherwise use the frame aspect ratio. This way a container setting, which is
2789	* usually easy to modify can override the coded value in the frames.
2790	*
2791	* @param format the format context which the stream is part of
2792	* @param stream the stream which the frame is part of
2793	* @param frame the frame with the aspect ratio to be determined
2794	* @return the guessed (valid) sample_aspect_ratio, 0/1 if no idea
2795	*/
2796	AVRational av_guess_sample_aspect_ratio(AVFormatContext format, AVStream stream,
2797	struct AVFrame *frame);
2798
2799	/**
2800	* Guess the frame rate, based on both the container and codec information.
2801	*
2802	* @param ctx the format context which the stream is part of
2803	* @param stream the stream which the frame is part of
2804	* @param frame the frame for which the frame rate should be determined, may be NULL
2805	* @return the guessed (valid) frame rate, 0/1 if no idea
2806	*/
2807	AVRational av_guess_frame_rate(AVFormatContext ctx, AVStream stream,
2808	struct AVFrame *frame);
2809
2810	/**
2811	* Check if the stream st contained in s is matched by the stream specifier
2812	* spec.
2813	*
2814	* See the "stream specifiers" chapter in the documentation for the syntax
2815	* of spec.
2816	*
2817	* @return >0 if st is matched by spec;
2818	* 0 if st is not matched by spec;
2819	* AVERROR code if spec is invalid
2820	*
2821	* @note A stream specifier can match several streams in the format.
2822	*/
2823	int avformat_match_stream_specifier(AVFormatContext s, AVStream st,
2824	const char *spec);
2825
2826	int avformat_queue_attached_pictures(AVFormatContext *s);
2827
2828	enum AVTimebaseSource {
2829	AVFMT_TBCF_AUTO = -`1`,
2830	AVFMT_TBCF_DECODER,
2831	AVFMT_TBCF_DEMUXER,
2832	#if FF_API_R_FRAME_RATE
2833	AVFMT_TBCF_R_FRAMERATE,
2834	#endif
2835	};
2836
2837	/**
2838	* Transfer internal timing information from one stream to another.
2839	*
2840	* This function is useful when doing stream copy.
2841	*
2842	* @param ofmt target output format for ost
2843	* @param ost output stream which needs timings copy and adjustments
2844	* @param ist reference input stream to copy timings from
2845	* @param copy_tb define from where the stream codec timebase needs to be imported
2846	*/
2847	int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
2848	AVStream ost, const* AVStream *ist,
2849	enum AVTimebaseSource copy_tb);
2850
2851	/**
2852	* Get the internal codec timebase from a stream.
2853	*
2854	* @param st input stream to extract the timebase from
2855	*/
2856	AVRational av_stream_get_codec_timebase(const AVStream *st);
2857
2858	/**
2859	* @}
2860	*/
2861
2862	#endif /* AVFORMAT_AVFORMAT_H */
2863

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