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 <time.h>
311	#include <stdio.h> /* FILE */
312	#include "libavcodec/avcodec.h"
313	#include "libavutil/dict.h"
314	#include "libavutil/log.h"
315
316	#include "avio.h"
317	#include "libavformat/version.h"
318
319	struct AVFormatContext;
320
321	struct AVDeviceInfoList;
322	struct AVDeviceCapabilitiesQuery;
323
324	/**
325	* @defgroup metadata_api Public Metadata API
326	* @{
327	* @ingroup libavf
328	* The metadata API allows libavformat to export metadata tags to a client
329	* application when demuxing. Conversely it allows a client application to
330	* set metadata when muxing.
331	*
332	* Metadata is exported or set as pairs of key/value strings in the 'metadata'
333	* fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
334	* using the @ref lavu_dict "AVDictionary" API. Like all strings in FFmpeg,
335	* metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
336	* exported by demuxers isn't checked to be valid UTF-8 in most cases.
337	*
338	* Important concepts to keep in mind:
339	* - Keys are unique; there can never be 2 tags with the same key. This is
340	* also meant semantically, i.e., a demuxer should not knowingly produce
341	* several keys that are literally different but semantically identical.
342	* E.g., key=Author5, key=Author6. In this example, all authors must be
343	* placed in the same tag.
344	* - Metadata is flat, not hierarchical; there are no subtags. If you
345	* want to store, e.g., the email address of the child of producer Alice
346	* and actor Bob, that could have key=alice_and_bobs_childs_email_address.
347	* - Several modifiers can be applied to the tag name. This is done by
348	* appending a dash character ('-') and the modifier name in the order
349	* they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
350	* - language -- a tag whose value is localized for a particular language
351	* is appended with the ISO 639-2/B 3-letter language code.
352	* For example: Author-ger=Michael, Author-eng=Mike
353	* The original/default language is in the unqualified "Author" tag.
354	* A demuxer should set a default if it sets any translated tag.
355	* - sorting -- a modified version of a tag that should be used for
356	* sorting will have '-sort' appended. E.g. artist="The Beatles",
357	* artist-sort="Beatles, The".
358	* - Some protocols and demuxers support metadata updates. After a successful
359	* call to av_read_frame(), AVFormatContext.event_flags or AVStream.event_flags
360	* will be updated to indicate if metadata changed. In order to detect metadata
361	* changes on a stream, you need to loop through all streams in the AVFormatContext
362	* and check their individual event_flags.
363	*
364	* - Demuxers attempt to export metadata in a generic format, however tags
365	* with no generic equivalents are left as they are stored in the container.
366	* Follows a list of generic tag names:
367	*
368	@verbatim
369	album -- name of the set this work belongs to
370	album_artist -- main creator of the set/album, if different from artist.
371	e.g. "Various Artists" for compilation albums.
372	artist -- main creator of the work
373	comment -- any additional description of the file.
374	composer -- who composed the work, if different from artist.
375	copyright -- name of copyright holder.
376	creation_time-- date when the file was created, preferably in ISO 8601.
377	date -- date when the work was created, preferably in ISO 8601.
378	disc -- number of a subset, e.g. disc in a multi-disc collection.
379	encoder -- name/settings of the software/hardware that produced the file.
380	encoded_by -- person/group who created the file.
381	filename -- original name of the file.
382	genre -- <self-evident>.
383	language -- main language in which the work is performed, preferably
384	in ISO 639-2 format. Multiple languages can be specified by
385	separating them with commas.
386	performer -- artist who performed the work, if different from artist.
387	E.g for "Also sprach Zarathustra", artist would be "Richard
388	Strauss" and performer "London Philharmonic Orchestra".
389	publisher -- name of the label/publisher.
390	service_name -- name of the service in broadcasting (channel name).
391	service_provider -- name of the service provider in broadcasting.
392	title -- name of the work.
393	track -- number of this work in the set, can be in form current/total.
394	variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
395	@endverbatim
396	*
397	* Look in the examples section for an application example how to use the Metadata API.
398	*
399	* @}
400	*/
401
402	/* packet functions */
403
404
405	/**
406	* Allocate and read the payload of a packet and initialize its
407	* fields with default values.
408	*
409	* @param s associated IO context
410	* @param pkt packet
411	* @param size desired payload size
412	* @return >0 (read size) if OK, AVERROR_xxx otherwise
413	*/
414	int av_get_packet(AVIOContext *s, AVPacket *pkt, int size);
415
416
417	/**
418	* Read data and append it to the current content of the AVPacket.
419	* If pkt->size is 0 this is identical to av_get_packet.
420	* Note that this uses av_grow_packet and thus involves a realloc
421	* which is inefficient. Thus this function should only be used
422	* when there is no reasonable way to know (an upper bound of)
423	* the final size.
424	*
425	* @param s associated IO context
426	* @param pkt packet
427	* @param size amount of data to read
428	* @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
429	* will not be lost even if an error occurs.
430	*/
431	int av_append_packet(AVIOContext *s, AVPacket *pkt, int size);
432
433	/*************************************************/
434	/* input/output formats */
435
436	struct AVCodecTag;
437
438	/**
439	* This structure contains the data a format has to probe a file.
440	*/
441	typedef struct AVProbeData {
442	const char *filename;
443	unsigned char *buf; /**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */
444	int buf_size; /**< Size of buf except extra allocated bytes */
445	const char *mime_type; /**< mime_type, when known. */
446	} AVProbeData;
447
448	#define AVPROBE_SCORE_RETRY (AVPROBE_SCORE_MAX/4)
449	#define AVPROBE_SCORE_STREAM_RETRY (AVPROBE_SCORE_MAX/4-1)
450
451	#define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
452	#define AVPROBE_SCORE_MIME 75 ///< score for file mime type
453	#define AVPROBE_SCORE_MAX 100 ///< maximum score
454
455	#define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
456
457	/// Demuxer will use avio_open, no opened file should be provided by the caller.
458	#define AVFMT_NOFILE 0x0001
459	#define AVFMT_NEEDNUMBER 0x0002 /**< Needs '%d' in filename. */
460	#define AVFMT_SHOW_IDS 0x0008 /**< Show format stream IDs numbers. */
461	#define AVFMT_GLOBALHEADER 0x0040 /**< Format wants global header. */
462	#define AVFMT_NOTIMESTAMPS 0x0080 /**< Format does not need / have any timestamps. */
463	#define AVFMT_GENERIC_INDEX 0x0100 /**< Use generic index building code. */
464	#define AVFMT_TS_DISCONT 0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
465	#define AVFMT_VARIABLE_FPS 0x0400 /**< Format allows variable fps. */
466	#define AVFMT_NODIMENSIONS 0x0800 /**< Format does not need width/height */
467	#define AVFMT_NOSTREAMS 0x1000 /**< Format does not require any streams */
468	#define AVFMT_NOBINSEARCH 0x2000 /**< Format does not allow to fall back on binary search via read_timestamp */
469	#define AVFMT_NOGENSEARCH 0x4000 /**< Format does not allow to fall back on generic search */
470	#define AVFMT_NO_BYTE_SEEK 0x8000 /**< Format does not allow seeking by bytes */
471	#define AVFMT_ALLOW_FLUSH 0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
472	#define AVFMT_TS_NONSTRICT 0x20000 /**< Format does not require strictly
473	increasing timestamps, but they must
474	still be monotonic */
475	#define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative
476	timestamps. If not set the timestamp
477	will be shifted in av_write_frame and
478	av_interleaved_write_frame so they
479	start from 0.
480	The user or muxer can override this through
481	AVFormatContext.avoid_negative_ts
482	*/
483
484	#define AVFMT_SEEK_TO_PTS 0x4000000 /**< Seeking is based on PTS */
485
486	/**
487	* @addtogroup lavf_encoding
488	* @{
489	*/
490	typedef struct AVOutputFormat {
491	const char *name;
492	/**
493	* Descriptive name for the format, meant to be more human-readable
494	* than name. You should use the NULL_IF_CONFIG_SMALL() macro
495	* to define it.
496	*/
497	const char *long_name;
498	const char *mime_type;
499	const char *extensions; /**< comma-separated filename extensions */
500	/* output support */
501	enum AVCodecID audio_codec; /**< default audio codec */
502	enum AVCodecID video_codec; /**< default video codec */
503	enum AVCodecID subtitle_codec; /**< default subtitle codec */
504	/**
505	* can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER,
506	* AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
507	* AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
508	* AVFMT_TS_NONSTRICT, AVFMT_TS_NEGATIVE
509	*/
510	int flags;
511
512	/**
513	* List of supported codec_id-codec_tag pairs, ordered by "better
514	* choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
515	*/
516	const struct AVCodecTag * const *codec_tag;
517
518
519	const AVClass *priv_class; ///< AVClass for the private context
520
521	/*****************************************************************
522	* No fields below this line are part of the public API. They
523	* may not be used outside of libavformat and can be changed and
524	* removed at will.
525	* New public fields should be added right above.
526	*****************************************************************
527	*/
528	/**
529	* The ff_const59 define is not part of the public API and will
530	* be removed without further warning.
531	*/
532	#if FF_API_AVIOFORMAT
533	#define ff_const59
534	#else
535	#define ff_const59 const
536	#endif
537	#if FF_API_NEXT
538	ff_const59 struct AVOutputFormat *next;
539	#endif
540	/**
541	* size of private data so that it can be allocated in the wrapper
542	*/
543	int priv_data_size;
544
545	int (*write_header)(struct AVFormatContext *);
546	/**
547	* Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,
548	* pkt can be NULL in order to flush data buffered in the muxer.
549	* When flushing, return 0 if there still is more data to flush,
550	* or 1 if everything was flushed and there is no more buffered
551	* data.
552	*/
553	int (*write_packet)(struct AVFormatContext *, AVPacket *pkt);
554	int (*write_trailer)(struct AVFormatContext *);
555	/**
556	* A format-specific function for interleavement.
557	* If unset, packets will be interleaved by dts.
558	*/
559	int (*interleave_packet)(struct AVFormatContext *, AVPacket *out,
560	AVPacket *in, int flush);
561	/**
562	* Test if the given codec can be stored in this container.
563	*
564	* @return 1 if the codec is supported, 0 if it is not.
565	* A negative number if unknown.
566	* MKTAG('A', 'P', 'I', 'C') if the codec is only supported as AV_DISPOSITION_ATTACHED_PIC
567	*/
568	int (*query_codec)(enum AVCodecID id, int std_compliance);
569
570	void (*get_output_timestamp)(struct AVFormatContext *s, int stream,
571	int64_t *dts, int64_t *wall);
572	/**
573	* Allows sending messages from application to device.
574	*/
575	int (*control_message)(struct AVFormatContext *s, int type,
576	void *data, size_t data_size);
577
578	/**
579	* Write an uncoded AVFrame.
580	*
581	* See av_write_uncoded_frame() for details.
582	*
583	* The library will free *frame afterwards, but the muxer can prevent it
584	* by setting the pointer to NULL.
585	*/
586	int (*write_uncoded_frame)(struct AVFormatContext *, int stream_index,
587	AVFrame **frame, unsigned flags);
588	/**
589	* Returns device list with it properties.
590	* @see avdevice_list_devices() for more details.
591	*/
592	int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list);
593	#if LIBAVFORMAT_VERSION_MAJOR < 59
594	/**
595	* Initialize device capabilities submodule.
596	* @see avdevice_capabilities_create() for more details.
597	*/
598	int (*create_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);
599	/**
600	* Free device capabilities submodule.
601	* @see avdevice_capabilities_free() for more details.
602	*/
603	int (*free_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);
604	#endif
605	enum AVCodecID data_codec; /**< default data codec */
606	/**
607	* Initialize format. May allocate data here, and set any AVFormatContext or
608	* AVStream parameters that need to be set before packets are sent.
609	* This method must not write output.
610	*
611	* Return 0 if streams were fully configured, 1 if not, negative AVERROR on failure
612	*
613	* Any allocations made here must be freed in deinit().
614	*/
615	int (*init)(struct AVFormatContext *);
616	/**
617	* Deinitialize format. If present, this is called whenever the muxer is being
618	* destroyed, regardless of whether or not the header has been written.
619	*
620	* If a trailer is being written, this is called after write_trailer().
621	*
622	* This is called if init() fails as well.
623	*/
624	void (*deinit)(struct AVFormatContext *);
625	/**
626	* Set up any necessary bitstream filtering and extract any extra data needed
627	* for the global header.
628	* Return 0 if more packets from this stream must be checked; 1 if not.
629	*/
630	int (*check_bitstream)(struct AVFormatContext *, const AVPacket *pkt);
631	} AVOutputFormat;
632	/**
633	* @}
634	*/
635
636	/**
637	* @addtogroup lavf_decoding
638	* @{
639	*/
640	typedef struct AVInputFormat {
641	/**
642	* A comma separated list of short names for the format. New names
643	* may be appended with a minor bump.
644	*/
645	const char *name;
646
647	/**
648	* Descriptive name for the format, meant to be more human-readable
649	* than name. You should use the NULL_IF_CONFIG_SMALL() macro
650	* to define it.
651	*/
652	const char *long_name;
653
654	/**
655	* Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
656	* AVFMT_NOTIMESTAMPS, AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
657	* AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK, AVFMT_SEEK_TO_PTS.
658	*/
659	int flags;
660
661	/**
662	* If extensions are defined, then no probe is done. You should
663	* usually not use extension format guessing because it is not
664	* reliable enough
665	*/
666	const char *extensions;
667
668	const struct AVCodecTag * const *codec_tag;
669
670	const AVClass *priv_class; ///< AVClass for the private context
671
672	/**
673	* Comma-separated list of mime types.
674	* It is used check for matching mime types while probing.
675	* @see av_probe_input_format2
676	*/
677	const char *mime_type;
678
679	/*****************************************************************
680	* No fields below this line are part of the public API. They
681	* may not be used outside of libavformat and can be changed and
682	* removed at will.
683	* New public fields should be added right above.
684	*****************************************************************
685	*/
686	#if FF_API_NEXT
687	ff_const59 struct AVInputFormat *next;
688	#endif
689
690	/**
691	* Raw demuxers store their codec ID here.
692	*/
693	int raw_codec_id;
694
695	/**
696	* Size of private data so that it can be allocated in the wrapper.
697	*/
698	int priv_data_size;
699
700	/**
701	* Tell if a given file has a chance of being parsed as this format.
702	* The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
703	* big so you do not have to check for that unless you need more.
704	*/
705	int (*read_probe)(const AVProbeData *);
706
707	/**
708	* Read the format header and initialize the AVFormatContext
709	* structure. Return 0 if OK. 'avformat_new_stream' should be
710	* called to create new streams.
711	*/
712	int (*read_header)(struct AVFormatContext *);
713
714	/**
715	* Read one packet and put it in 'pkt'. pts and flags are also
716	* set. 'avformat_new_stream' can be called only if the flag
717	* AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
718	* background thread).
719	* @return 0 on success, < 0 on error.
720	* Upon returning an error, pkt must be unreferenced by the caller.
721	*/
722	int (*read_packet)(struct AVFormatContext *, AVPacket *pkt);
723
724	/**
725	* Close the stream. The AVFormatContext and AVStreams are not
726	* freed by this function
727	*/
728	int (*read_close)(struct AVFormatContext *);
729
730	/**
731	* Seek to a given timestamp relative to the frames in
732	* stream component stream_index.
733	* @param stream_index Must not be -1.
734	* @param flags Selects which direction should be preferred if no exact
735	* match is available.
736	* @return >= 0 on success (but not necessarily the new offset)
737	*/
738	int (*read_seek)(struct AVFormatContext *,
739	int stream_index, int64_t timestamp, int flags);
740
741	/**
742	* Get the next timestamp in stream[stream_index].time_base units.
743	* @return the timestamp or AV_NOPTS_VALUE if an error occurred
744	*/
745	int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index,
746	int64_t *pos, int64_t pos_limit);
747
748	/**
749	* Start/resume playing - only meaningful if using a network-based format
750	* (RTSP).
751	*/
752	int (*read_play)(struct AVFormatContext *);
753
754	/**
755	* Pause playing - only meaningful if using a network-based format
756	* (RTSP).
757	*/
758	int (*read_pause)(struct AVFormatContext *);
759
760	/**
761	* Seek to timestamp ts.
762	* Seeking will be done so that the point from which all active streams
763	* can be presented successfully will be closest to ts and within min/max_ts.
764	* Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
765	*/
766	int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
767
768	/**
769	* Returns device list with it properties.
770	* @see avdevice_list_devices() for more details.
771	*/
772	int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list);
773
774	#if LIBAVFORMAT_VERSION_MAJOR < 59
775	/**
776	* Initialize device capabilities submodule.
777	* @see avdevice_capabilities_create() for more details.
778	*/
779	int (*create_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);
780
781	/**
782	* Free device capabilities submodule.
783	* @see avdevice_capabilities_free() for more details.
784	*/
785	int (*free_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);
786	#endif
787	} AVInputFormat;
788	/**
789	* @}
790	*/
791
792	enum AVStreamParseType {
793	AVSTREAM_PARSE_NONE,
794	AVSTREAM_PARSE_FULL, /**< full parsing and repack */
795	AVSTREAM_PARSE_HEADERS, /**< Only parse headers, do not repack. */
796	AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */
797	AVSTREAM_PARSE_FULL_ONCE, /**< full parsing and repack of the first frame only, only implemented for H.264 currently */
798	AVSTREAM_PARSE_FULL_RAW, /**< full parsing and repack with timestamp and position generation by parser for raw
799	this assumes that each packet in the file contains no demuxer level headers and
800	just codec level data, otherwise position generation would fail */
801	};
802
803	typedef struct AVIndexEntry {
804	int64_t pos;
805	int64_t timestamp; /**<
806	* Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are available
807	* when seeking to this entry. That means preferable PTS on keyframe based formats.
808	* But demuxers can choose to store a different timestamp, if it is more convenient for the implementation or nothing better
809	* is known
810	*/
811	#define AVINDEX_KEYFRAME 0x0001
812	#define AVINDEX_DISCARD_FRAME 0x0002 /**
813	* Flag is used to indicate which frame should be discarded after decoding.
814	*/
815	int flags:2;
816	int size:30; //Yeah, trying to keep the size of this small to reduce memory requirements (it is 24 vs. 32 bytes due to possible 8-byte alignment).
817	int min_distance; /**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */
818	} AVIndexEntry;
819
820	#define AV_DISPOSITION_DEFAULT 0x0001
821	#define AV_DISPOSITION_DUB 0x0002
822	#define AV_DISPOSITION_ORIGINAL 0x0004
823	#define AV_DISPOSITION_COMMENT 0x0008
824	#define AV_DISPOSITION_LYRICS 0x0010
825	#define AV_DISPOSITION_KARAOKE 0x0020
826
827	/**
828	* Track should be used during playback by default.
829	* Useful for subtitle track that should be displayed
830	* even when user did not explicitly ask for subtitles.
831	*/
832	#define AV_DISPOSITION_FORCED 0x0040
833	#define AV_DISPOSITION_HEARING_IMPAIRED 0x0080 /**< stream for hearing impaired audiences */
834	#define AV_DISPOSITION_VISUAL_IMPAIRED 0x0100 /**< stream for visual impaired audiences */
835	#define AV_DISPOSITION_CLEAN_EFFECTS 0x0200 /**< stream without voice */
836	/**
837	* The stream is stored in the file as an attached picture/"cover art" (e.g.
838	* APIC frame in ID3v2). The first (usually only) packet associated with it
839	* will be returned among the first few packets read from the file unless
840	* seeking takes place. It can also be accessed at any time in
841	* AVStream.attached_pic.
842	*/
843	#define AV_DISPOSITION_ATTACHED_PIC 0x0400
844	/**
845	* The stream is sparse, and contains thumbnail images, often corresponding
846	* to chapter markers. Only ever used with AV_DISPOSITION_ATTACHED_PIC.
847	*/
848	#define AV_DISPOSITION_TIMED_THUMBNAILS 0x0800
849
850	typedef struct AVStreamInternal AVStreamInternal;
851
852	/**
853	* To specify text track kind (different from subtitles default).
854	*/
855	#define AV_DISPOSITION_CAPTIONS 0x10000
856	#define AV_DISPOSITION_DESCRIPTIONS 0x20000
857	#define AV_DISPOSITION_METADATA 0x40000
858	#define AV_DISPOSITION_DEPENDENT 0x80000 ///< dependent audio stream (mix_type=0 in mpegts)
859	#define AV_DISPOSITION_STILL_IMAGE 0x100000 ///< still images in video stream (still_picture_flag=1 in mpegts)
860
861	/**
862	* Options for behavior on timestamp wrap detection.
863	*/
864	#define AV_PTS_WRAP_IGNORE 0 ///< ignore the wrap
865	#define AV_PTS_WRAP_ADD_OFFSET 1 ///< add the format specific offset on wrap detection
866	#define AV_PTS_WRAP_SUB_OFFSET -1 ///< subtract the format specific offset on wrap detection
867
868	/**
869	* Stream structure.
870	* New fields can be added to the end with minor version bumps.
871	* Removal, reordering and changes to existing fields require a major
872	* version bump.
873	* sizeof(AVStream) must not be used outside libav*.
874	*/
875	typedef struct AVStream {
876	int index; /**< stream index in AVFormatContext */
877	/**
878	* Format-specific stream ID.
879	* decoding: set by libavformat
880	* encoding: set by the user, replaced by libavformat if left unset
881	*/
882	int id;
883	#if FF_API_LAVF_AVCTX
884	/**
885	* @deprecated use the codecpar struct instead
886	*/
887	attribute_deprecated
888	AVCodecContext *codec;
889	#endif
890	void *priv_data;
891
892	/**
893	* This is the fundamental unit of time (in seconds) in terms
894	* of which frame timestamps are represented.
895	*
896	* decoding: set by libavformat
897	* encoding: May be set by the caller before avformat_write_header() to
898	* provide a hint to the muxer about the desired timebase. In
899	* avformat_write_header(), the muxer will overwrite this field
900	* with the timebase that will actually be used for the timestamps
901	* written into the file (which may or may not be related to the
902	* user-provided one, depending on the format).
903	*/
904	AVRational time_base;
905
906	/**
907	* Decoding: pts of the first frame of the stream in presentation order, in stream time base.
908	* Only set this if you are absolutely 100% sure that the value you set
909	* it to really is the pts of the first frame.
910	* This may be undefined (AV_NOPTS_VALUE).
911	* @note The ASF header does NOT contain a correct start_time the ASF
912	* demuxer must NOT set this.
913	*/
914	int64_t start_time;
915
916	/**
917	* Decoding: duration of the stream, in stream time base.
918	* If a source file does not specify a duration, but does specify
919	* a bitrate, this value will be estimated from bitrate and file size.
920	*
921	* Encoding: May be set by the caller before avformat_write_header() to
922	* provide a hint to the muxer about the estimated duration.
923	*/
924	int64_t duration;
925
926	int64_t nb_frames; ///< number of frames in this stream if known or 0
927
928	int disposition; /**< AV_DISPOSITION_* bit field */
929
930	enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
931
932	/**
933	* sample aspect ratio (0 if unknown)
934	* - encoding: Set by user.
935	* - decoding: Set by libavformat.
936	*/
937	AVRational sample_aspect_ratio;
938
939	AVDictionary *metadata;
940
941	/**
942	* Average framerate
943	*
944	* - demuxing: May be set by libavformat when creating the stream or in
945	* avformat_find_stream_info().
946	* - muxing: May be set by the caller before avformat_write_header().
947	*/
948	AVRational avg_frame_rate;
949
950	/**
951	* For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
952	* will contain the attached picture.
953	*
954	* decoding: set by libavformat, must not be modified by the caller.
955	* encoding: unused
956	*/
957	AVPacket attached_pic;
958
959	/**
960	* An array of side data that applies to the whole stream (i.e. the
961	* container does not allow it to change between packets).
962	*
963	* There may be no overlap between the side data in this array and side data
964	* in the packets. I.e. a given side data is either exported by the muxer
965	* (demuxing) / set by the caller (muxing) in this array, then it never
966	* appears in the packets, or the side data is exported / sent through
967	* the packets (always in the first packet where the value becomes known or
968	* changes), then it does not appear in this array.
969	*
970	* - demuxing: Set by libavformat when the stream is created.
971	* - muxing: May be set by the caller before avformat_write_header().
972	*
973	* Freed by libavformat in avformat_free_context().
974	*
975	* @see av_format_inject_global_side_data()
976	*/
977	AVPacketSideData *side_data;
978	/**
979	* The number of elements in the AVStream.side_data array.
980	*/
981	int nb_side_data;
982
983	/**
984	* Flags indicating events happening on the stream, a combination of
985	* AVSTREAM_EVENT_FLAG_*.
986	*
987	* - demuxing: may be set by the demuxer in avformat_open_input(),
988	* avformat_find_stream_info() and av_read_frame(). Flags must be cleared
989	* by the user once the event has been handled.
990	* - muxing: may be set by the user after avformat_write_header(). to
991	* indicate a user-triggered event. The muxer will clear the flags for
992	* events it has handled in av_[interleaved]_write_frame().
993	*/
994	int event_flags;
995	/**
996	* - demuxing: the demuxer read new metadata from the file and updated
997	* AVStream.metadata accordingly
998	* - muxing: the user updated AVStream.metadata and wishes the muxer to write
999	* it into the file
1000	*/
1001	#define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001
1002	/**
1003	* - demuxing: new packets for this stream were read from the file. This
1004	* event is informational only and does not guarantee that new packets
1005	* for this stream will necessarily be returned from av_read_frame().
1006	*/
1007	#define AVSTREAM_EVENT_FLAG_NEW_PACKETS (1 << 1)
1008
1009	/**
1010	* Real base framerate of the stream.
1011	* This is the lowest framerate with which all timestamps can be
1012	* represented accurately (it is the least common multiple of all
1013	* framerates in the stream). Note, this value is just a guess!
1014	* For example, if the time base is 1/90000 and all frames have either
1015	* approximately 3600 or 1800 timer ticks, then r_frame_rate will be 50/1.
1016	*/
1017	AVRational r_frame_rate;
1018
1019	#if FF_API_LAVF_FFSERVER
1020	/**
1021	* String containing pairs of key and values describing recommended encoder configuration.
1022	* Pairs are separated by ','.
1023	* Keys are separated from values by '='.
1024	*
1025	* @deprecated unused
1026	*/
1027	attribute_deprecated
1028	char *recommended_encoder_configuration;
1029	#endif
1030
1031	/**
1032	* Codec parameters associated with this stream. Allocated and freed by
1033	* libavformat in avformat_new_stream() and avformat_free_context()
1034	* respectively.
1035	*
1036	* - demuxing: filled by libavformat on stream creation or in
1037	* avformat_find_stream_info()
1038	* - muxing: filled by the caller before avformat_write_header()
1039	*/
1040	AVCodecParameters *codecpar;
1041
1042	/*****************************************************************
1043	* All fields below this line are not part of the public API. They
1044	* may not be used outside of libavformat and can be changed and
1045	* removed at will.
1046	* Internal note: be aware that physically removing these fields
1047	* will break ABI. Replace removed fields with dummy fields, and
1048	* add new fields to AVStreamInternal.
1049	*****************************************************************
1050	*/
1051
1052	#if LIBAVFORMAT_VERSION_MAJOR < 59
1053	// kept for ABI compatibility only, do not access in any way
1054	void *unused;
1055	#endif
1056
1057	int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
1058
1059	// Timestamp generation support:
1060	/**
1061	* Timestamp corresponding to the last dts sync point.
1062	*
1063	* Initialized when AVCodecParserContext.dts_sync_point >= 0 and
1064	* a DTS is received from the underlying container. Otherwise set to
1065	* AV_NOPTS_VALUE by default.
1066	*/
1067	int64_t first_dts;
1068	int64_t cur_dts;
1069	int64_t last_IP_pts;
1070	int last_IP_duration;
1071
1072	/**
1073	* Number of packets to buffer for codec probing
1074	*/
1075	int probe_packets;
1076
1077	/**
1078	* Number of frames that have been demuxed during avformat_find_stream_info()
1079	*/
1080	int codec_info_nb_frames;
1081
1082	/* av_read_frame() support */
1083	enum AVStreamParseType need_parsing;
1084	struct AVCodecParserContext *parser;
1085
1086	#if LIBAVFORMAT_VERSION_MAJOR < 59
1087	// kept for ABI compatibility only, do not access in any way
1088	void *unused7;
1089	AVProbeData unused6;
1090	int64_t unused5[16+1];
1091	#endif
1092	AVIndexEntry *index_entries; /**< Only used if the format does not
1093	support seeking natively. */
1094	int nb_index_entries;
1095	unsigned int index_entries_allocated_size;
1096
1097	/**
1098	* Stream Identifier
1099	* This is the MPEG-TS stream identifier +1
1100	* 0 means unknown
1101	*/
1102	int stream_identifier;
1103
1104	#if LIBAVFORMAT_VERSION_MAJOR < 59
1105	// kept for ABI compatibility only, do not access in any way
1106	int unused8;
1107	int unused9;
1108	int unused10;
1109	#endif
1110
1111	/**
1112	* An opaque field for libavformat internal usage.
1113	* Must not be accessed in any way by callers.
1114	*/
1115	AVStreamInternal *internal;
1116	} AVStream;
1117
1118	#if FF_API_FORMAT_GET_SET
1119	/**
1120	* Accessors for some AVStream fields. These used to be provided for ABI
1121	* compatibility, and do not need to be used anymore.
1122	*/
1123	attribute_deprecated
1124	AVRational av_stream_get_r_frame_rate(const AVStream *s);
1125	attribute_deprecated
1126	void av_stream_set_r_frame_rate(AVStream *s, AVRational r);
1127	#if FF_API_LAVF_FFSERVER
1128	attribute_deprecated
1129	char* av_stream_get_recommended_encoder_configuration(const AVStream *s);
1130	attribute_deprecated
1131	void av_stream_set_recommended_encoder_configuration(AVStream *s, char *configuration);
1132	#endif
1133	#endif
1134
1135	struct AVCodecParserContext *av_stream_get_parser(const AVStream *s);
1136
1137	/**
1138	* Returns the pts of the last muxed packet + its duration
1139	*
1140	* the retuned value is undefined when used with a demuxer.
1141	*/
1142	int64_t av_stream_get_end_pts(const AVStream *st);
1143
1144	#define AV_PROGRAM_RUNNING 1
1145
1146	/**
1147	* New fields can be added to the end with minor version bumps.
1148	* Removal, reordering and changes to existing fields require a major
1149	* version bump.
1150	* sizeof(AVProgram) must not be used outside libav*.
1151	*/
1152	typedef struct AVProgram {
1153	int id;
1154	int flags;
1155	enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
1156	unsigned int *stream_index;
1157	unsigned int nb_stream_indexes;
1158	AVDictionary *metadata;
1159
1160	int program_num;
1161	int pmt_pid;
1162	int pcr_pid;
1163	int pmt_version;
1164
1165	/*****************************************************************
1166	* All fields below this line are not part of the public API. They
1167	* may not be used outside of libavformat and can be changed and
1168	* removed at will.
1169	* New public fields should be added right above.
1170	*****************************************************************
1171	*/
1172	int64_t start_time;
1173	int64_t end_time;
1174
1175	int64_t pts_wrap_reference; ///< reference dts for wrap detection
1176	int pts_wrap_behavior; ///< behavior on wrap detection
1177	} AVProgram;
1178
1179	#define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
1180	(streams are added dynamically) */
1181	#define AVFMTCTX_UNSEEKABLE 0x0002 /**< signal that the stream is definitely
1182	not seekable, and attempts to call the
1183	seek function will fail. For some
1184	network protocols (e.g. HLS), this can
1185	change dynamically at runtime. */
1186
1187	typedef struct AVChapter {
1188	#if FF_API_CHAPTER_ID_INT
1189	int id; ///< unique ID to identify the chapter
1190	#else
1191	int64_t id; ///< unique ID to identify the chapter
1192	#endif
1193	AVRational time_base; ///< time base in which the start/end timestamps are specified
1194	int64_t start, end; ///< chapter start/end time in time_base units
1195	AVDictionary *metadata;
1196	} AVChapter;
1197
1198
1199	/**
1200	* Callback used by devices to communicate with application.
1201	*/
1202	typedef int (*av_format_control_message)(struct AVFormatContext *s, int type,
1203	void *data, size_t data_size);
1204
1205	typedef int (*AVOpenCallback)(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags,
1206	const AVIOInterruptCB *int_cb, AVDictionary **options);
1207
1208	/**
1209	* The duration of a video can be estimated through various ways, and this enum can be used
1210	* to know how the duration was estimated.
1211	*/
1212	enum AVDurationEstimationMethod {
1213	AVFMT_DURATION_FROM_PTS, ///< Duration accurately estimated from PTSes
1214	AVFMT_DURATION_FROM_STREAM, ///< Duration estimated from a stream with a known duration
1215	AVFMT_DURATION_FROM_BITRATE ///< Duration estimated from bitrate (less accurate)
1216	};
1217
1218	typedef struct AVFormatInternal AVFormatInternal;
1219
1220	/**
1221	* Format I/O context.
1222	* New fields can be added to the end with minor version bumps.
1223	* Removal, reordering and changes to existing fields require a major
1224	* version bump.
1225	* sizeof(AVFormatContext) must not be used outside libav*, use
1226	* avformat_alloc_context() to create an AVFormatContext.
1227	*
1228	* Fields can be accessed through AVOptions (av_opt*),
1229	* the name string used matches the associated command line parameter name and
1230	* can be found in libavformat/options_table.h.
1231	* The AVOption/command line parameter names differ in some cases from the C
1232	* structure field names for historic reasons or brevity.
1233	*/
1234	typedef struct AVFormatContext {
1235	/**
1236	* A class for logging and @ref avoptions. Set by avformat_alloc_context().
1237	* Exports (de)muxer private options if they exist.
1238	*/
1239	const AVClass *av_class;
1240
1241	/**
1242	* The input container format.
1243	*
1244	* Demuxing only, set by avformat_open_input().
1245	*/
1246	ff_const59 struct AVInputFormat *iformat;
1247
1248	/**
1249	* The output container format.
1250	*
1251	* Muxing only, must be set by the caller before avformat_write_header().
1252	*/
1253	ff_const59 struct AVOutputFormat *oformat;
1254
1255	/**
1256	* Format private data. This is an AVOptions-enabled struct
1257	* if and only if iformat/oformat.priv_class is not NULL.
1258	*
1259	* - muxing: set by avformat_write_header()
1260	* - demuxing: set by avformat_open_input()
1261	*/
1262	void *priv_data;
1263
1264	/**
1265	* I/O context.
1266	*
1267	* - demuxing: either set by the user before avformat_open_input() (then
1268	* the user must close it manually) or set by avformat_open_input().
1269	* - muxing: set by the user before avformat_write_header(). The caller must
1270	* take care of closing / freeing the IO context.
1271	*
1272	* Do NOT set this field if AVFMT_NOFILE flag is set in
1273	* iformat/oformat.flags. In such a case, the (de)muxer will handle
1274	* I/O in some other way and this field will be NULL.
1275	*/
1276	AVIOContext *pb;
1277
1278	/* stream info */
1279	/**
1280	* Flags signalling stream properties. A combination of AVFMTCTX_*.
1281	* Set by libavformat.
1282	*/
1283	int ctx_flags;
1284
1285	/**
1286	* Number of elements in AVFormatContext.streams.
1287	*
1288	* Set by avformat_new_stream(), must not be modified by any other code.
1289	*/
1290	unsigned int nb_streams;
1291	/**
1292	* A list of all streams in the file. New streams are created with
1293	* avformat_new_stream().
1294	*
1295	* - demuxing: streams are created by libavformat in avformat_open_input().
1296	* If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
1297	* appear in av_read_frame().
1298	* - muxing: streams are created by the user before avformat_write_header().
1299	*
1300	* Freed by libavformat in avformat_free_context().
1301	*/
1302	AVStream **streams;
1303
1304	#if FF_API_FORMAT_FILENAME
1305	/**
1306	* input or output filename
1307	*
1308	* - demuxing: set by avformat_open_input()
1309	* - muxing: may be set by the caller before avformat_write_header()
1310	*
1311	* @deprecated Use url instead.
1312	*/
1313	attribute_deprecated
1314	char filename[1024];
1315	#endif
1316
1317	/**
1318	* input or output URL. Unlike the old filename field, this field has no
1319	* length restriction.
1320	*
1321	* - demuxing: set by avformat_open_input(), initialized to an empty
1322	* string if url parameter was NULL in avformat_open_input().
1323	* - muxing: may be set by the caller before calling avformat_write_header()
1324	* (or avformat_init_output() if that is called first) to a string
1325	* which is freeable by av_free(). Set to an empty string if it
1326	* was NULL in avformat_init_output().
1327	*
1328	* Freed by libavformat in avformat_free_context().
1329	*/
1330	char *url;
1331
1332	/**
1333	* Position of the first frame of the component, in
1334	* AV_TIME_BASE fractional seconds. NEVER set this value directly:
1335	* It is deduced from the AVStream values.
1336	*
1337	* Demuxing only, set by libavformat.
1338	*/
1339	int64_t start_time;
1340
1341	/**
1342	* Duration of the stream, in AV_TIME_BASE fractional
1343	* seconds. Only set this value if you know none of the individual stream
1344	* durations and also do not set any of them. This is deduced from the
1345	* AVStream values if not set.
1346	*
1347	* Demuxing only, set by libavformat.
1348	*/
1349	int64_t duration;
1350
1351	/**
1352	* Total stream bitrate in bit/s, 0 if not
1353	* available. Never set it directly if the file_size and the
1354	* duration are known as FFmpeg can compute it automatically.
1355	*/
1356	int64_t bit_rate;
1357
1358	unsigned int packet_size;
1359	int max_delay;
1360
1361	/**
1362	* Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
1363	* Set by the user before avformat_open_input() / avformat_write_header().
1364	*/
1365	int flags;
1366	#define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
1367	#define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
1368	#define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
1369	#define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
1370	#define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container
1371	#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
1372	#define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
1373	#define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
1374	#define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
1375	#define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
1376	/**
1377	* When muxing, try to avoid writing any random/volatile data to the output.
1378	* This includes any random IDs, real-time timestamps/dates, muxer version, etc.
1379	*
1380	* This flag is mainly intended for testing.
1381	*/
1382	#define AVFMT_FLAG_BITEXACT 0x0400
1383	#if FF_API_LAVF_MP4A_LATM
1384	#define AVFMT_FLAG_MP4A_LATM 0x8000 ///< Deprecated, does nothing.
1385	#endif
1386	#define AVFMT_FLAG_SORT_DTS 0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
1387	#if FF_API_LAVF_PRIV_OPT
1388	#define AVFMT_FLAG_PRIV_OPT 0x20000 ///< Enable use of private options by delaying codec open (deprecated, will do nothing once av_demuxer_open() is removed)
1389	#endif
1390	#if FF_API_LAVF_KEEPSIDE_FLAG
1391	#define AVFMT_FLAG_KEEP_SIDE_DATA 0x40000 ///< Deprecated, does nothing.
1392	#endif
1393	#define AVFMT_FLAG_FAST_SEEK 0x80000 ///< Enable fast, but inaccurate seeks for some formats
1394	#define AVFMT_FLAG_SHORTEST 0x100000 ///< Stop muxing when the shortest stream stops.
1395	#define AVFMT_FLAG_AUTO_BSF 0x200000 ///< Add bitstream filters as requested by the muxer
1396
1397	/**
1398	* Maximum size of the data read from input for determining
1399	* the input container format.
1400	* Demuxing only, set by the caller before avformat_open_input().
1401	*/
1402	int64_t probesize;
1403
1404	/**
1405	* Maximum duration (in AV_TIME_BASE units) of the data read
1406	* from input in avformat_find_stream_info().
1407	* Demuxing only, set by the caller before avformat_find_stream_info().
1408	* Can be set to 0 to let avformat choose using a heuristic.
1409	*/
1410	int64_t max_analyze_duration;
1411
1412	const uint8_t *key;
1413	int keylen;
1414
1415	unsigned int nb_programs;
1416	AVProgram **programs;
1417
1418	/**
1419	* Forced video codec_id.
1420	* Demuxing: Set by user.
1421	*/
1422	enum AVCodecID video_codec_id;
1423
1424	/**
1425	* Forced audio codec_id.
1426	* Demuxing: Set by user.
1427	*/
1428	enum AVCodecID audio_codec_id;
1429
1430	/**
1431	* Forced subtitle codec_id.
1432	* Demuxing: Set by user.
1433	*/
1434	enum AVCodecID subtitle_codec_id;
1435
1436	/**
1437	* Maximum amount of memory in bytes to use for the index of each stream.
1438	* If the index exceeds this size, entries will be discarded as
1439	* needed to maintain a smaller size. This can lead to slower or less
1440	* accurate seeking (depends on demuxer).
1441	* Demuxers for which a full in-memory index is mandatory will ignore
1442	* this.
1443	* - muxing: unused
1444	* - demuxing: set by user
1445	*/
1446	unsigned int max_index_size;
1447
1448	/**
1449	* Maximum amount of memory in bytes to use for buffering frames
1450	* obtained from realtime capture devices.
1451	*/
1452	unsigned int max_picture_buffer;
1453
1454	/**
1455	* Number of chapters in AVChapter array.
1456	* When muxing, chapters are normally written in the file header,
1457	* so nb_chapters should normally be initialized before write_header
1458	* is called. Some muxers (e.g. mov and mkv) can also write chapters
1459	* in the trailer. To write chapters in the trailer, nb_chapters
1460	* must be zero when write_header is called and non-zero when
1461	* write_trailer is called.
1462	* - muxing: set by user
1463	* - demuxing: set by libavformat
1464	*/
1465	unsigned int nb_chapters;
1466	AVChapter **chapters;
1467
1468	/**
1469	* Metadata that applies to the whole file.
1470	*
1471	* - demuxing: set by libavformat in avformat_open_input()
1472	* - muxing: may be set by the caller before avformat_write_header()
1473	*
1474	* Freed by libavformat in avformat_free_context().
1475	*/
1476	AVDictionary *metadata;
1477
1478	/**
1479	* Start time of the stream in real world time, in microseconds
1480	* since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1481	* stream was captured at this real world time.
1482	* - muxing: Set by the caller before avformat_write_header(). If set to
1483	* either 0 or AV_NOPTS_VALUE, then the current wall-time will
1484	* be used.
1485	* - demuxing: Set by libavformat. AV_NOPTS_VALUE if unknown. Note that
1486	* the value may become known after some number of frames
1487	* have been received.
1488	*/
1489	int64_t start_time_realtime;
1490
1491	/**
1492	* The number of frames used for determining the framerate in
1493	* avformat_find_stream_info().
1494	* Demuxing only, set by the caller before avformat_find_stream_info().
1495	*/
1496	int fps_probe_size;
1497
1498	/**
1499	* Error recognition; higher values will detect more errors but may
1500	* misdetect some more or less valid parts as errors.
1501	* Demuxing only, set by the caller before avformat_open_input().
1502	*/
1503	int error_recognition;
1504
1505	/**
1506	* Custom interrupt callbacks for the I/O layer.
1507	*
1508	* demuxing: set by the user before avformat_open_input().
1509	* muxing: set by the user before avformat_write_header()
1510	* (mainly useful for AVFMT_NOFILE formats). The callback
1511	* should also be passed to avio_open2() if it's used to
1512	* open the file.
1513	*/
1514	AVIOInterruptCB interrupt_callback;
1515
1516	/**
1517	* Flags to enable debugging.
1518	*/
1519	int debug;
1520	#define FF_FDEBUG_TS 0x0001
1521
1522	/**
1523	* Maximum buffering duration for interleaving.
1524	*
1525	* To ensure all the streams are interleaved correctly,
1526	* av_interleaved_write_frame() will wait until it has at least one packet
1527	* for each stream before actually writing any packets to the output file.
1528	* When some streams are "sparse" (i.e. there are large gaps between
1529	* successive packets), this can result in excessive buffering.
1530	*
1531	* This field specifies the maximum difference between the timestamps of the
1532	* first and the last packet in the muxing queue, above which libavformat
1533	* will output a packet regardless of whether it has queued a packet for all
1534	* the streams.
1535	*
1536	* Muxing only, set by the caller before avformat_write_header().
1537	*/
1538	int64_t max_interleave_delta;
1539
1540	/**
1541	* Allow non-standard and experimental extension
1542	* @see AVCodecContext.strict_std_compliance
1543	*/
1544	int strict_std_compliance;
1545
1546	/**
1547	* Flags indicating events happening on the file, a combination of
1548	* AVFMT_EVENT_FLAG_*.
1549	*
1550	* - demuxing: may be set by the demuxer in avformat_open_input(),
1551	* avformat_find_stream_info() and av_read_frame(). Flags must be cleared
1552	* by the user once the event has been handled.
1553	* - muxing: may be set by the user after avformat_write_header() to
1554	* indicate a user-triggered event. The muxer will clear the flags for
1555	* events it has handled in av_[interleaved]_write_frame().
1556	*/
1557	int event_flags;
1558	/**
1559	* - demuxing: the demuxer read new metadata from the file and updated
1560	* AVFormatContext.metadata accordingly
1561	* - muxing: the user updated AVFormatContext.metadata and wishes the muxer to
1562	* write it into the file
1563	*/
1564	#define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001
1565
1566	/**
1567	* Maximum number of packets to read while waiting for the first timestamp.
1568	* Decoding only.
1569	*/
1570	int max_ts_probe;
1571
1572	/**
1573	* Avoid negative timestamps during muxing.
1574	* Any value of the AVFMT_AVOID_NEG_TS_* constants.
1575	* Note, this only works when using av_interleaved_write_frame. (interleave_packet_per_dts is in use)
1576	* - muxing: Set by user
1577	* - demuxing: unused
1578	*/
1579	int avoid_negative_ts;
1580	#define AVFMT_AVOID_NEG_TS_AUTO -1 ///< Enabled when required by target format
1581	#define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
1582	#define AVFMT_AVOID_NEG_TS_MAKE_ZERO 2 ///< Shift timestamps so that they start at 0
1583
1584	/**
1585	* Transport stream id.
1586	* This will be moved into demuxer private options. Thus no API/ABI compatibility
1587	*/
1588	int ts_id;
1589
1590	/**
1591	* Audio preload in microseconds.
1592	* Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1593	* - encoding: Set by user
1594	* - decoding: unused
1595	*/
1596	int audio_preload;
1597
1598	/**
1599	* Max chunk time in microseconds.
1600	* Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1601	* - encoding: Set by user
1602	* - decoding: unused
1603	*/
1604	int max_chunk_duration;
1605
1606	/**
1607	* Max chunk size in bytes
1608	* Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1609	* - encoding: Set by user
1610	* - decoding: unused
1611	*/
1612	int max_chunk_size;
1613
1614	/**
1615	* forces the use of wallclock timestamps as pts/dts of packets
1616	* This has undefined results in the presence of B frames.
1617	* - encoding: unused
1618	* - decoding: Set by user
1619	*/
1620	int use_wallclock_as_timestamps;
1621
1622	/**
1623	* avio flags, used to force AVIO_FLAG_DIRECT.
1624	* - encoding: unused
1625	* - decoding: Set by user
1626	*/
1627	int avio_flags;
1628
1629	/**
1630	* The duration field can be estimated through various ways, and this field can be used
1631	* to know how the duration was estimated.
1632	* - encoding: unused
1633	* - decoding: Read by user
1634	*/
1635	enum AVDurationEstimationMethod duration_estimation_method;
1636
1637	/**
1638	* Skip initial bytes when opening stream
1639	* - encoding: unused
1640	* - decoding: Set by user
1641	*/
1642	int64_t skip_initial_bytes;
1643
1644	/**
1645	* Correct single timestamp overflows
1646	* - encoding: unused
1647	* - decoding: Set by user
1648	*/
1649	unsigned int correct_ts_overflow;
1650
1651	/**
1652	* Force seeking to any (also non key) frames.
1653	* - encoding: unused
1654	* - decoding: Set by user
1655	*/
1656	int seek2any;
1657
1658	/**
1659	* Flush the I/O context after each packet.
1660	* - encoding: Set by user
1661	* - decoding: unused
1662	*/
1663	int flush_packets;
1664
1665	/**
1666	* format probing score.
1667	* The maximal score is AVPROBE_SCORE_MAX, its set when the demuxer probes
1668	* the format.
1669	* - encoding: unused
1670	* - decoding: set by avformat, read by user
1671	*/
1672	int probe_score;
1673
1674	/**
1675	* number of bytes to read maximally to identify format.
1676	* - encoding: unused
1677	* - decoding: set by user
1678	*/
1679	int format_probesize;
1680
1681	/**
1682	* ',' separated list of allowed decoders.
1683	* If NULL then all are allowed
1684	* - encoding: unused
1685	* - decoding: set by user
1686	*/
1687	char *codec_whitelist;
1688
1689	/**
1690	* ',' separated list of allowed demuxers.
1691	* If NULL then all are allowed
1692	* - encoding: unused
1693	* - decoding: set by user
1694	*/
1695	char *format_whitelist;
1696
1697	/**
1698	* An opaque field for libavformat internal usage.
1699	* Must not be accessed in any way by callers.
1700	*/
1701	AVFormatInternal *internal;
1702
1703	/**
1704	* IO repositioned flag.
1705	* This is set by avformat when the underlaying IO context read pointer
1706	* is repositioned, for example when doing byte based seeking.
1707	* Demuxers can use the flag to detect such changes.
1708	*/
1709	int io_repositioned;
1710
1711	/**
1712	* Forced video codec.
1713	* This allows forcing a specific decoder, even when there are multiple with
1714	* the same codec_id.
1715	* Demuxing: Set by user
1716	*/
1717	AVCodec *video_codec;
1718
1719	/**
1720	* Forced audio codec.
1721	* This allows forcing a specific decoder, even when there are multiple with
1722	* the same codec_id.
1723	* Demuxing: Set by user
1724	*/
1725	AVCodec *audio_codec;
1726
1727	/**
1728	* Forced subtitle codec.
1729	* This allows forcing a specific decoder, even when there are multiple with
1730	* the same codec_id.
1731	* Demuxing: Set by user
1732	*/
1733	AVCodec *subtitle_codec;
1734
1735	/**
1736	* Forced data codec.
1737	* This allows forcing a specific decoder, even when there are multiple with
1738	* the same codec_id.
1739	* Demuxing: Set by user
1740	*/
1741	AVCodec *data_codec;
1742
1743	/**
1744	* Number of bytes to be written as padding in a metadata header.
1745	* Demuxing: Unused.
1746	* Muxing: Set by user via av_format_set_metadata_header_padding.
1747	*/
1748	int metadata_header_padding;
1749
1750	/**
1751	* User data.
1752	* This is a place for some private data of the user.
1753	*/
1754	void *opaque;
1755
1756	/**
1757	* Callback used by devices to communicate with application.
1758	*/
1759	av_format_control_message control_message_cb;
1760
1761	/**
1762	* Output timestamp offset, in microseconds.
1763	* Muxing: set by user
1764	*/
1765	int64_t output_ts_offset;
1766
1767	/**
1768	* dump format separator.
1769	* can be ", " or "\n " or anything else
1770	* - muxing: Set by user.
1771	* - demuxing: Set by user.
1772	*/
1773	uint8_t *dump_separator;
1774
1775	/**
1776	* Forced Data codec_id.
1777	* Demuxing: Set by user.
1778	*/
1779	enum AVCodecID data_codec_id;
1780
1781	#if FF_API_OLD_OPEN_CALLBACKS
1782	/**
1783	* Called to open further IO contexts when needed for demuxing.
1784	*
1785	* This can be set by the user application to perform security checks on
1786	* the URLs before opening them.
1787	* The function should behave like avio_open2(), AVFormatContext is provided
1788	* as contextual information and to reach AVFormatContext.opaque.
1789	*
1790	* If NULL then some simple checks are used together with avio_open2().
1791	*
1792	* Must not be accessed directly from outside avformat.
1793	* @See av_format_set_open_cb()
1794	*
1795	* Demuxing: Set by user.
1796	*
1797	* @deprecated Use io_open and io_close.
1798	*/
1799	attribute_deprecated
1800	int (*open_cb)(struct AVFormatContext *s, AVIOContext **p, const char *url, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options);
1801	#endif
1802
1803	/**
1804	* ',' separated list of allowed protocols.
1805	* - encoding: unused
1806	* - decoding: set by user
1807	*/
1808	char *protocol_whitelist;
1809
1810	/**
1811	* A callback for opening new IO streams.
1812	*
1813	* Whenever a muxer or a demuxer needs to open an IO stream (typically from
1814	* avformat_open_input() for demuxers, but for certain formats can happen at
1815	* other times as well), it will call this callback to obtain an IO context.
1816	*
1817	* @param s the format context
1818	* @param pb on success, the newly opened IO context should be returned here
1819	* @param url the url to open
1820	* @param flags a combination of AVIO_FLAG_*
1821	* @param options a dictionary of additional options, with the same
1822	* semantics as in avio_open2()
1823	* @return 0 on success, a negative AVERROR code on failure
1824	*
1825	* @note Certain muxers and demuxers do nesting, i.e. they open one or more
1826	* additional internal format contexts. Thus the AVFormatContext pointer
1827	* passed to this callback may be different from the one facing the caller.
1828	* It will, however, have the same 'opaque' field.
1829	*/
1830	int (*io_open)(struct AVFormatContext *s, AVIOContext **pb, const char *url,
1831	int flags, AVDictionary **options);
1832
1833	/**
1834	* A callback for closing the streams opened with AVFormatContext.io_open().
1835	*/
1836	void (*io_close)(struct AVFormatContext *s, AVIOContext *pb);
1837
1838	/**
1839	* ',' separated list of disallowed protocols.
1840	* - encoding: unused
1841	* - decoding: set by user
1842	*/
1843	char *protocol_blacklist;
1844
1845	/**
1846	* The maximum number of streams.
1847	* - encoding: unused
1848	* - decoding: set by user
1849	*/
1850	int max_streams;
1851
1852	/**
1853	* Skip duration calcuation in estimate_timings_from_pts.
1854	* - encoding: unused
1855	* - decoding: set by user
1856	*/
1857	int skip_estimate_duration_from_pts;
1858
1859	/**
1860	* Maximum number of packets that can be probed
1861	* - encoding: unused
1862	* - decoding: set by user
1863	*/
1864	int max_probe_packets;
1865	} AVFormatContext;
1866
1867	#if FF_API_FORMAT_GET_SET
1868	/**
1869	* Accessors for some AVFormatContext fields. These used to be provided for ABI
1870	* compatibility, and do not need to be used anymore.
1871	*/
1872	attribute_deprecated
1873	int av_format_get_probe_score(const AVFormatContext *s);
1874	attribute_deprecated
1875	AVCodec * av_format_get_video_codec(const AVFormatContext *s);
1876	attribute_deprecated
1877	void av_format_set_video_codec(AVFormatContext *s, AVCodec *c);
1878	attribute_deprecated
1879	AVCodec * av_format_get_audio_codec(const AVFormatContext *s);
1880	attribute_deprecated
1881	void av_format_set_audio_codec(AVFormatContext *s, AVCodec *c);
1882	attribute_deprecated
1883	AVCodec * av_format_get_subtitle_codec(const AVFormatContext *s);
1884	attribute_deprecated
1885	void av_format_set_subtitle_codec(AVFormatContext *s, AVCodec *c);
1886	attribute_deprecated
1887	AVCodec * av_format_get_data_codec(const AVFormatContext *s);
1888	attribute_deprecated
1889	void av_format_set_data_codec(AVFormatContext *s, AVCodec *c);
1890	attribute_deprecated
1891	int av_format_get_metadata_header_padding(const AVFormatContext *s);
1892	attribute_deprecated
1893	void av_format_set_metadata_header_padding(AVFormatContext *s, int c);
1894	attribute_deprecated
1895	void * av_format_get_opaque(const AVFormatContext *s);
1896	attribute_deprecated
1897	void av_format_set_opaque(AVFormatContext *s, void *opaque);
1898	attribute_deprecated
1899	av_format_control_message av_format_get_control_message_cb(const AVFormatContext *s);
1900	attribute_deprecated
1901	void av_format_set_control_message_cb(AVFormatContext *s, av_format_control_message callback);
1902	#if FF_API_OLD_OPEN_CALLBACKS
1903	attribute_deprecated AVOpenCallback av_format_get_open_cb(const AVFormatContext *s);
1904	attribute_deprecated void av_format_set_open_cb(AVFormatContext *s, AVOpenCallback callback);
1905	#endif
1906	#endif
1907
1908	/**
1909	* This function will cause global side data to be injected in the next packet
1910	* of each stream as well as after any subsequent seek.
1911	*/
1912	void av_format_inject_global_side_data(AVFormatContext *s);
1913
1914	/**
1915	* Returns the method used to set ctx->duration.
1916	*
1917	* @return AVFMT_DURATION_FROM_PTS, AVFMT_DURATION_FROM_STREAM, or AVFMT_DURATION_FROM_BITRATE.
1918	*/
1919	enum AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext* ctx);
1920
1921	/**
1922	* @defgroup lavf_core Core functions
1923	* @ingroup libavf
1924	*
1925	* Functions for querying libavformat capabilities, allocating core structures,
1926	* etc.
1927	* @{
1928	*/
1929
1930	/**
1931	* Return the LIBAVFORMAT_VERSION_INT constant.
1932	*/
1933	unsigned avformat_version(void);
1934
1935	/**
1936	* Return the libavformat build-time configuration.
1937	*/
1938	const char *avformat_configuration(void);
1939
1940	/**
1941	* Return the libavformat license.
1942	*/
1943	const char *avformat_license(void);
1944
1945	#if FF_API_NEXT
1946	/**
1947	* Initialize libavformat and register all the muxers, demuxers and
1948	* protocols. If you do not call this function, then you can select
1949	* exactly which formats you want to support.
1950	*
1951	* @see av_register_input_format()
1952	* @see av_register_output_format()
1953	*/
1954	attribute_deprecated
1955	void av_register_all(void);
1956
1957	attribute_deprecated
1958	void av_register_input_format(AVInputFormat *format);
1959	attribute_deprecated
1960	void av_register_output_format(AVOutputFormat *format);
1961	#endif
1962
1963	/**
1964	* Do global initialization of network libraries. This is optional,
1965	* and not recommended anymore.
1966	*
1967	* This functions only exists to work around thread-safety issues
1968	* with older GnuTLS or OpenSSL libraries. If libavformat is linked
1969	* to newer versions of those libraries, or if you do not use them,
1970	* calling this function is unnecessary. Otherwise, you need to call
1971	* this function before any other threads using them are started.
1972	*
1973	* This function will be deprecated once support for older GnuTLS and
1974	* OpenSSL libraries is removed, and this function has no purpose
1975	* anymore.
1976	*/
1977	int avformat_network_init(void);
1978
1979	/**
1980	* Undo the initialization done by avformat_network_init. Call it only
1981	* once for each time you called avformat_network_init.
1982	*/
1983	int avformat_network_deinit(void);
1984
1985	#if FF_API_NEXT
1986	/**
1987	* If f is NULL, returns the first registered input format,
1988	* if f is non-NULL, returns the next registered input format after f
1989	* or NULL if f is the last one.
1990	*/
1991	attribute_deprecated
1992	AVInputFormat *av_iformat_next(const AVInputFormat *f);
1993
1994	/**
1995	* If f is NULL, returns the first registered output format,
1996	* if f is non-NULL, returns the next registered output format after f
1997	* or NULL if f is the last one.
1998	*/
1999	attribute_deprecated
2000	AVOutputFormat *av_oformat_next(const AVOutputFormat *f);
2001	#endif
2002
2003	/**
2004	* Iterate over all registered muxers.
2005	*
2006	* @param opaque a pointer where libavformat will store the iteration state. Must
2007	* point to NULL to start the iteration.
2008	*
2009	* @return the next registered muxer or NULL when the iteration is
2010	* finished
2011	*/
2012	const AVOutputFormat *av_muxer_iterate(void **opaque);
2013
2014	/**
2015	* Iterate over all registered demuxers.
2016	*
2017	* @param opaque a pointer where libavformat will store the iteration state. Must
2018	* point to NULL to start the iteration.
2019	*
2020	* @return the next registered demuxer or NULL when the iteration is
2021	* finished
2022	*/
2023	const AVInputFormat *av_demuxer_iterate(void **opaque);
2024
2025	/**
2026	* Allocate an AVFormatContext.
2027	* avformat_free_context() can be used to free the context and everything
2028	* allocated by the framework within it.
2029	*/
2030	AVFormatContext *avformat_alloc_context(void);
2031
2032	/**
2033	* Free an AVFormatContext and all its streams.
2034	* @param s context to free
2035	*/
2036	void avformat_free_context(AVFormatContext *s);
2037
2038	/**
2039	* Get the AVClass for AVFormatContext. It can be used in combination with
2040	* AV_OPT_SEARCH_FAKE_OBJ for examining options.
2041	*
2042	* @see av_opt_find().
2043	*/
2044	const AVClass *avformat_get_class(void);
2045
2046	/**
2047	* Add a new stream to a media file.
2048	*
2049	* When demuxing, it is called by the demuxer in read_header(). If the
2050	* flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
2051	* be called in read_packet().
2052	*
2053	* When muxing, should be called by the user before avformat_write_header().
2054	*
2055	* User is required to call avcodec_close() and avformat_free_context() to
2056	* clean up the allocation by avformat_new_stream().
2057	*
2058	* @param s media file handle
2059	* @param c If non-NULL, the AVCodecContext corresponding to the new stream
2060	* will be initialized to use this codec. This is needed for e.g. codec-specific
2061	* defaults to be set, so codec should be provided if it is known.
2062	*
2063	* @return newly created stream or NULL on error.
2064	*/
2065	AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c);
2066
2067	/**
2068	* Wrap an existing array as stream side data.
2069	*
2070	* @param st stream
2071	* @param type side information type
2072	* @param data the side data array. It must be allocated with the av_malloc()
2073	* family of functions. The ownership of the data is transferred to
2074	* st.
2075	* @param size side information size
2076	* @return zero on success, a negative AVERROR code on failure. On failure,
2077	* the stream is unchanged and the data remains owned by the caller.
2078	*/
2079	int av_stream_add_side_data(AVStream *st, enum AVPacketSideDataType type,
2080	uint8_t *data, size_t size);
2081
2082	/**
2083	* Allocate new information from stream.
2084	*
2085	* @param stream stream
2086	* @param type desired side information type
2087	* @param size side information size
2088	* @return pointer to fresh allocated data or NULL otherwise
2089	*/
2090	uint8_t *av_stream_new_side_data(AVStream *stream,
2091	#if FF_API_BUFFER_SIZE_T
2092	enum AVPacketSideDataType type, int size);
2093	#else
2094	enum AVPacketSideDataType type, size_t size);
2095	#endif
2096	/**
2097	* Get side information from stream.
2098	*
2099	* @param stream stream
2100	* @param type desired side information type
2101	* @param size If supplied, *size will be set to the size of the side data
2102	* or to zero if the desired side data is not present.
2103	* @return pointer to data if present or NULL otherwise
2104	*/
2105	uint8_t *av_stream_get_side_data(const AVStream *stream,
2106	#if FF_API_BUFFER_SIZE_T
2107	enum AVPacketSideDataType type, int *size);
2108	#else
2109	enum AVPacketSideDataType type, size_t *size);
2110	#endif
2111
2112	AVProgram *av_new_program(AVFormatContext *s, int id);
2113
2114	/**
2115	* @}
2116	*/
2117
2118
2119	/**
2120	* Allocate an AVFormatContext for an output format.
2121	* avformat_free_context() can be used to free the context and
2122	* everything allocated by the framework within it.
2123	*
2124	* @param *ctx is set to the created format context, or to NULL in
2125	* case of failure
2126	* @param oformat format to use for allocating the context, if NULL
2127	* format_name and filename are used instead
2128	* @param format_name the name of output format to use for allocating the
2129	* context, if NULL filename is used instead
2130	* @param filename the name of the filename to use for allocating the
2131	* context, may be NULL
2132	* @return >= 0 in case of success, a negative AVERROR code in case of
2133	* failure
2134	*/
2135	int avformat_alloc_output_context2(AVFormatContext **ctx, ff_const59 AVOutputFormat *oformat,
2136	const char *format_name, const char *filename);
2137
2138	/**
2139	* @addtogroup lavf_decoding
2140	* @{
2141	*/
2142
2143	/**
2144	* Find AVInputFormat based on the short name of the input format.
2145	*/
2146	ff_const59 AVInputFormat *av_find_input_format(const char *short_name);
2147
2148	/**
2149	* Guess the file format.
2150	*
2151	* @param pd data to be probed
2152	* @param is_opened Whether the file is already opened; determines whether
2153	* demuxers with or without AVFMT_NOFILE are probed.
2154	*/
2155	ff_const59 AVInputFormat *av_probe_input_format(ff_const59 AVProbeData *pd, int is_opened);
2156
2157	/**
2158	* Guess the file format.
2159	*
2160	* @param pd data to be probed
2161	* @param is_opened Whether the file is already opened; determines whether
2162	* demuxers with or without AVFMT_NOFILE are probed.
2163	* @param score_max A probe score larger that this is required to accept a
2164	* detection, the variable is set to the actual detection
2165	* score afterwards.
2166	* If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
2167	* to retry with a larger probe buffer.
2168	*/
2169	ff_const59 AVInputFormat *av_probe_input_format2(ff_const59 AVProbeData *pd, int is_opened, int *score_max);
2170
2171	/**
2172	* Guess the file format.
2173	*
2174	* @param is_opened Whether the file is already opened; determines whether
2175	* demuxers with or without AVFMT_NOFILE are probed.
2176	* @param score_ret The score of the best detection.
2177	*/
2178	ff_const59 AVInputFormat *av_probe_input_format3(ff_const59 AVProbeData *pd, int is_opened, int *score_ret);
2179
2180	/**
2181	* Probe a bytestream to determine the input format. Each time a probe returns
2182	* with a score that is too low, the probe buffer size is increased and another
2183	* attempt is made. When the maximum probe size is reached, the input format
2184	* with the highest score is returned.
2185	*
2186	* @param pb the bytestream to probe
2187	* @param fmt the input format is put here
2188	* @param url the url of the stream
2189	* @param logctx the log context
2190	* @param offset the offset within the bytestream to probe from
2191	* @param max_probe_size the maximum probe buffer size (zero for default)
2192	* @return the score in case of success, a negative value corresponding to an
2193	* the maximal score is AVPROBE_SCORE_MAX
2194	* AVERROR code otherwise
2195	*/
2196	int av_probe_input_buffer2(AVIOContext *pb, ff_const59 AVInputFormat **fmt,
2197	const char *url, void *logctx,
2198	unsigned int offset, unsigned int max_probe_size);
2199
2200	/**
2201	* Like av_probe_input_buffer2() but returns 0 on success
2202	*/
2203	int av_probe_input_buffer(AVIOContext *pb, ff_const59 AVInputFormat **fmt,
2204	const char *url, void *logctx,
2205	unsigned int offset, unsigned int max_probe_size);
2206
2207	/**
2208	* Open an input stream and read the header. The codecs are not opened.
2209	* The stream must be closed with avformat_close_input().
2210	*
2211	* @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
2212	* May be a pointer to NULL, in which case an AVFormatContext is allocated by this
2213	* function and written into ps.
2214	* Note that a user-supplied AVFormatContext will be freed on failure.
2215	* @param url URL of the stream to open.
2216	* @param fmt If non-NULL, this parameter forces a specific input format.
2217	* Otherwise the format is autodetected.
2218	* @param options A dictionary filled with AVFormatContext and demuxer-private options.
2219	* On return this parameter will be destroyed and replaced with a dict containing
2220	* options that were not found. May be NULL.
2221	*
2222	* @return 0 on success, a negative AVERROR on failure.
2223	*
2224	* @note If you want to use custom IO, preallocate the format context and set its pb field.
2225	*/
2226	int avformat_open_input(AVFormatContext **ps, const char *url, ff_const59 AVInputFormat *fmt, AVDictionary **options);
2227
2228	#if FF_API_DEMUXER_OPEN
2229	/**
2230	* @deprecated Use an AVDictionary to pass options to a demuxer.
2231	*/
2232	attribute_deprecated
2233	int av_demuxer_open(AVFormatContext *ic);
2234	#endif
2235
2236	/**
2237	* Read packets of a media file to get stream information. This
2238	* is useful for file formats with no headers such as MPEG. This
2239	* function also computes the real framerate in case of MPEG-2 repeat
2240	* frame mode.
2241	* The logical file position is not changed by this function;
2242	* examined packets may be buffered for later processing.
2243	*
2244	* @param ic media file handle
2245	* @param options If non-NULL, an ic.nb_streams long array of pointers to
2246	* dictionaries, where i-th member contains options for
2247	* codec corresponding to i-th stream.
2248	* On return each dictionary will be filled with options that were not found.
2249	* @return >=0 if OK, AVERROR_xxx on error
2250	*
2251	* @note this function isn't guaranteed to open all the codecs, so
2252	* options being non-empty at return is a perfectly normal behavior.
2253	*
2254	* @todo Let the user decide somehow what information is needed so that
2255	* we do not waste time getting stuff the user does not need.
2256	*/
2257	int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options);
2258
2259	/**
2260	* Find the programs which belong to a given stream.
2261	*
2262	* @param ic media file handle
2263	* @param last the last found program, the search will start after this
2264	* program, or from the beginning if it is NULL
2265	* @param s stream index
2266	* @return the next program which belongs to s, NULL if no program is found or
2267	* the last program is not among the programs of ic.
2268	*/
2269	AVProgram *av_find_program_from_stream(AVFormatContext *ic, AVProgram *last, int s);
2270
2271	void av_program_add_stream_index(AVFormatContext *ac, int progid, unsigned int idx);
2272
2273	/**
2274	* Find the "best" stream in the file.
2275	* The best stream is determined according to various heuristics as the most
2276	* likely to be what the user expects.
2277	* If the decoder parameter is non-NULL, av_find_best_stream will find the
2278	* default decoder for the stream's codec; streams for which no decoder can
2279	* be found are ignored.
2280	*
2281	* @param ic media file handle
2282	* @param type stream type: video, audio, subtitles, etc.
2283	* @param wanted_stream_nb user-requested stream number,
2284	* or -1 for automatic selection
2285	* @param related_stream try to find a stream related (eg. in the same
2286	* program) to this one, or -1 if none
2287	* @param decoder_ret if non-NULL, returns the decoder for the
2288	* selected stream
2289	* @param flags flags; none are currently defined
2290	* @return the non-negative stream number in case of success,
2291	* AVERROR_STREAM_NOT_FOUND if no stream with the requested type
2292	* could be found,
2293	* AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
2294	* @note If av_find_best_stream returns successfully and decoder_ret is not
2295	* NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
2296	*/
2297	int av_find_best_stream(AVFormatContext *ic,
2298	enum AVMediaType type,
2299	int wanted_stream_nb,
2300	int related_stream,
2301	AVCodec **decoder_ret,
2302	int flags);
2303
2304	/**
2305	* Return the next frame of a stream.
2306	* This function returns what is stored in the file, and does not validate
2307	* that what is there are valid frames for the decoder. It will split what is
2308	* stored in the file into frames and return one for each call. It will not
2309	* omit invalid data between valid frames so as to give the decoder the maximum
2310	* information possible for decoding.
2311	*
2312	* On success, the returned packet is reference-counted (pkt->buf is set) and
2313	* valid indefinitely. The packet must be freed with av_packet_unref() when
2314	* it is no longer needed. For video, the packet contains exactly one frame.
2315	* For audio, it contains an integer number of frames if each frame has
2316	* a known fixed size (e.g. PCM or ADPCM data). If the audio frames have
2317	* a variable size (e.g. MPEG audio), then it contains one frame.
2318	*
2319	* pkt->pts, pkt->dts and pkt->duration are always set to correct
2320	* values in AVStream.time_base units (and guessed if the format cannot
2321	* provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
2322	* has B-frames, so it is better to rely on pkt->dts if you do not
2323	* decompress the payload.
2324	*
2325	* @return 0 if OK, < 0 on error or end of file. On error, pkt will be blank
2326	* (as if it came from av_packet_alloc()).
2327	*
2328	* @note pkt will be initialized, so it may be uninitialized, but it must not
2329	* contain data that needs to be freed.
2330	*/
2331	int av_read_frame(AVFormatContext *s, AVPacket *pkt);
2332
2333	/**
2334	* Seek to the keyframe at timestamp.
2335	* 'timestamp' in 'stream_index'.
2336	*
2337	* @param s media file handle
2338	* @param stream_index If stream_index is (-1), a default
2339	* stream is selected, and timestamp is automatically converted
2340	* from AV_TIME_BASE units to the stream specific time_base.
2341	* @param timestamp Timestamp in AVStream.time_base units
2342	* or, if no stream is specified, in AV_TIME_BASE units.
2343	* @param flags flags which select direction and seeking mode
2344	* @return >= 0 on success
2345	*/
2346	int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
2347	int flags);
2348
2349	/**
2350	* Seek to timestamp ts.
2351	* Seeking will be done so that the point from which all active streams
2352	* can be presented successfully will be closest to ts and within min/max_ts.
2353	* Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
2354	*
2355	* If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
2356	* are the file position (this may not be supported by all demuxers).
2357	* If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
2358	* in the stream with stream_index (this may not be supported by all demuxers).
2359	* Otherwise all timestamps are in units of the stream selected by stream_index
2360	* or if stream_index is -1, in AV_TIME_BASE units.
2361	* If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
2362	* keyframes (this may not be supported by all demuxers).
2363	* If flags contain AVSEEK_FLAG_BACKWARD, it is ignored.
2364	*
2365	* @param s media file handle
2366	* @param stream_index index of the stream which is used as time base reference
2367	* @param min_ts smallest acceptable timestamp
2368	* @param ts target timestamp
2369	* @param max_ts largest acceptable timestamp
2370	* @param flags flags
2371	* @return >=0 on success, error code otherwise
2372	*
2373	* @note This is part of the new seek API which is still under construction.
2374	*/
2375	int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
2376
2377	/**
2378	* Discard all internally buffered data. This can be useful when dealing with
2379	* discontinuities in the byte stream. Generally works only with formats that
2380	* can resync. This includes headerless formats like MPEG-TS/TS but should also
2381	* work with NUT, Ogg and in a limited way AVI for example.
2382	*
2383	* The set of streams, the detected duration, stream parameters and codecs do
2384	* not change when calling this function. If you want a complete reset, it's
2385	* better to open a new AVFormatContext.
2386	*
2387	* This does not flush the AVIOContext (s->pb). If necessary, call
2388	* avio_flush(s->pb) before calling this function.
2389	*
2390	* @param s media file handle
2391	* @return >=0 on success, error code otherwise
2392	*/
2393	int avformat_flush(AVFormatContext *s);
2394
2395	/**
2396	* Start playing a network-based stream (e.g. RTSP stream) at the
2397	* current position.
2398	*/
2399	int av_read_play(AVFormatContext *s);
2400
2401	/**
2402	* Pause a network-based stream (e.g. RTSP stream).
2403	*
2404	* Use av_read_play() to resume it.
2405	*/
2406	int av_read_pause(AVFormatContext *s);
2407
2408	/**
2409	* Close an opened input AVFormatContext. Free it and all its contents
2410	* and set *s to NULL.
2411	*/
2412	void avformat_close_input(AVFormatContext **s);
2413	/**
2414	* @}
2415	*/
2416
2417	#define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
2418	#define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
2419	#define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
2420	#define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
2421
2422	/**
2423	* @addtogroup lavf_encoding
2424	* @{
2425	*/
2426
2427	#define AVSTREAM_INIT_IN_WRITE_HEADER 0 ///< stream parameters initialized in avformat_write_header
2428	#define AVSTREAM_INIT_IN_INIT_OUTPUT 1 ///< stream parameters initialized in avformat_init_output
2429
2430	/**
2431	* Allocate the stream private data and write the stream header to
2432	* an output media file.
2433	*
2434	* @param s Media file handle, must be allocated with avformat_alloc_context().
2435	* Its oformat field must be set to the desired output format;
2436	* Its pb field must be set to an already opened AVIOContext.
2437	* @param options An AVDictionary filled with AVFormatContext and muxer-private options.
2438	* On return this parameter will be destroyed and replaced with a dict containing
2439	* options that were not found. May be NULL.
2440	*
2441	* @return AVSTREAM_INIT_IN_WRITE_HEADER on success if the codec had not already been fully initialized in avformat_init,
2442	* AVSTREAM_INIT_IN_INIT_OUTPUT on success if the codec had already been fully initialized in avformat_init,
2443	* negative AVERROR on failure.
2444	*
2445	* @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_init_output.
2446	*/
2447	av_warn_unused_result
2448	int avformat_write_header(AVFormatContext *s, AVDictionary **options);
2449
2450	/**
2451	* Allocate the stream private data and initialize the codec, but do not write the header.
2452	* May optionally be used before avformat_write_header to initialize stream parameters
2453	* before actually writing the header.
2454	* If using this function, do not pass the same options to avformat_write_header.
2455	*
2456	* @param s Media file handle, must be allocated with avformat_alloc_context().
2457	* Its oformat field must be set to the desired output format;
2458	* Its pb field must be set to an already opened AVIOContext.
2459	* @param options An AVDictionary filled with AVFormatContext and muxer-private options.
2460	* On return this parameter will be destroyed and replaced with a dict containing
2461	* options that were not found. May be NULL.
2462	*
2463	* @return AVSTREAM_INIT_IN_WRITE_HEADER on success if the codec requires avformat_write_header to fully initialize,
2464	* AVSTREAM_INIT_IN_INIT_OUTPUT on success if the codec has been fully initialized,
2465	* negative AVERROR on failure.
2466	*
2467	* @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_write_header.
2468	*/
2469	av_warn_unused_result
2470	int avformat_init_output(AVFormatContext *s, AVDictionary **options);
2471
2472	/**
2473	* Write a packet to an output media file.
2474	*
2475	* This function passes the packet directly to the muxer, without any buffering
2476	* or reordering. The caller is responsible for correctly interleaving the
2477	* packets if the format requires it. Callers that want libavformat to handle
2478	* the interleaving should call av_interleaved_write_frame() instead of this
2479	* function.
2480	*
2481	* @param s media file handle
2482	* @param pkt The packet containing the data to be written. Note that unlike
2483	* av_interleaved_write_frame(), this function does not take
2484	* ownership of the packet passed to it (though some muxers may make
2485	* an internal reference to the input packet).
2486	* <br>
2487	* This parameter can be NULL (at any time, not just at the end), in
2488	* order to immediately flush data buffered within the muxer, for
2489	* muxers that buffer up data internally before writing it to the
2490	* output.
2491	* <br>
2492	* Packet's @ref AVPacket.stream_index "stream_index" field must be
2493	* set to the index of the corresponding stream in @ref
2494	* AVFormatContext.streams "s->streams".
2495	* <br>
2496	* The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2497	* must be set to correct values in the stream's timebase (unless the
2498	* output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2499	* they can be set to AV_NOPTS_VALUE).
2500	* The dts for subsequent packets passed to this function must be strictly
2501	* increasing when compared in their respective timebases (unless the
2502	* output format is flagged with the AVFMT_TS_NONSTRICT, then they
2503	* merely have to be nondecreasing). @ref AVPacket.duration
2504	* "duration") should also be set if known.
2505	* @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
2506	*
2507	* @see av_interleaved_write_frame()
2508	*/
2509	int av_write_frame(AVFormatContext *s, AVPacket *pkt);
2510
2511	/**
2512	* Write a packet to an output media file ensuring correct interleaving.
2513	*
2514	* This function will buffer the packets internally as needed to make sure the
2515	* packets in the output file are properly interleaved in the order of
2516	* increasing dts. Callers doing their own interleaving should call
2517	* av_write_frame() instead of this function.
2518	*
2519	* Using this function instead of av_write_frame() can give muxers advance
2520	* knowledge of future packets, improving e.g. the behaviour of the mp4
2521	* muxer for VFR content in fragmenting mode.
2522	*
2523	* @param s media file handle
2524	* @param pkt The packet containing the data to be written.
2525	* <br>
2526	* If the packet is reference-counted, this function will take
2527	* ownership of this reference and unreference it later when it sees
2528	* fit.
2529	* The caller must not access the data through this reference after
2530	* this function returns. If the packet is not reference-counted,
2531	* libavformat will make a copy.
2532	* <br>
2533	* This parameter can be NULL (at any time, not just at the end), to
2534	* flush the interleaving queues.
2535	* <br>
2536	* Packet's @ref AVPacket.stream_index "stream_index" field must be
2537	* set to the index of the corresponding stream in @ref
2538	* AVFormatContext.streams "s->streams".
2539	* <br>
2540	* The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2541	* must be set to correct values in the stream's timebase (unless the
2542	* output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2543	* they can be set to AV_NOPTS_VALUE).
2544	* The dts for subsequent packets in one stream must be strictly
2545	* increasing (unless the output format is flagged with the
2546	* AVFMT_TS_NONSTRICT, then they merely have to be nondecreasing).
2547	* @ref AVPacket.duration "duration") should also be set if known.
2548	*
2549	* @return 0 on success, a negative AVERROR on error. Libavformat will always
2550	* take care of freeing the packet, even if this function fails.
2551	*
2552	* @see av_write_frame(), AVFormatContext.max_interleave_delta
2553	*/
2554	int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
2555
2556	/**
2557	* Write an uncoded frame to an output media file.
2558	*
2559	* The frame must be correctly interleaved according to the container
2560	* specification; if not, av_interleaved_write_uncoded_frame() must be used.
2561	*
2562	* See av_interleaved_write_uncoded_frame() for details.
2563	*/
2564	int av_write_uncoded_frame(AVFormatContext *s, int stream_index,
2565	AVFrame *frame);
2566
2567	/**
2568	* Write an uncoded frame to an output media file.
2569	*
2570	* If the muxer supports it, this function makes it possible to write an AVFrame
2571	* structure directly, without encoding it into a packet.
2572	* It is mostly useful for devices and similar special muxers that use raw
2573	* video or PCM data and will not serialize it into a byte stream.
2574	*
2575	* To test whether it is possible to use it with a given muxer and stream,
2576	* use av_write_uncoded_frame_query().
2577	*
2578	* The caller gives up ownership of the frame and must not access it
2579	* afterwards.
2580	*
2581	* @return >=0 for success, a negative code on error
2582	*/
2583	int av_interleaved_write_uncoded_frame(AVFormatContext *s, int stream_index,
2584	AVFrame *frame);
2585
2586	/**
2587	* Test whether a muxer supports uncoded frame.
2588	*
2589	* @return >=0 if an uncoded frame can be written to that muxer and stream,
2590	* <0 if not
2591	*/
2592	int av_write_uncoded_frame_query(AVFormatContext *s, int stream_index);
2593
2594	/**
2595	* Write the stream trailer to an output media file and free the
2596	* file private data.
2597	*
2598	* May only be called after a successful call to avformat_write_header.
2599	*
2600	* @param s media file handle
2601	* @return 0 if OK, AVERROR_xxx on error
2602	*/
2603	int av_write_trailer(AVFormatContext *s);
2604
2605	/**
2606	* Return the output format in the list of registered output formats
2607	* which best matches the provided parameters, or return NULL if
2608	* there is no match.
2609	*
2610	* @param short_name if non-NULL checks if short_name matches with the
2611	* names of the registered formats
2612	* @param filename if non-NULL checks if filename terminates with the
2613	* extensions of the registered formats
2614	* @param mime_type if non-NULL checks if mime_type matches with the
2615	* MIME type of the registered formats
2616	*/
2617	ff_const59 AVOutputFormat *av_guess_format(const char *short_name,
2618	const char *filename,
2619	const char *mime_type);
2620
2621	/**
2622	* Guess the codec ID based upon muxer and filename.
2623	*/
2624	enum AVCodecID av_guess_codec(ff_const59 AVOutputFormat *fmt, const char *short_name,
2625	const char *filename, const char *mime_type,
2626	enum AVMediaType type);
2627
2628	/**
2629	* Get timing information for the data currently output.
2630	* The exact meaning of "currently output" depends on the format.
2631	* It is mostly relevant for devices that have an internal buffer and/or
2632	* work in real time.
2633	* @param s media file handle
2634	* @param stream stream in the media file
2635	* @param[out] dts DTS of the last packet output for the stream, in stream
2636	* time_base units
2637	* @param[out] wall absolute time when that packet whas output,
2638	* in microsecond
2639	* @return 0 if OK, AVERROR(ENOSYS) if the format does not support it
2640	* Note: some formats or devices may not allow to measure dts and wall
2641	* atomically.
2642	*/
2643	int av_get_output_timestamp(struct AVFormatContext *s, int stream,
2644	int64_t *dts, int64_t *wall);
2645
2646
2647	/**
2648	* @}
2649	*/
2650
2651
2652	/**
2653	* @defgroup lavf_misc Utility functions
2654	* @ingroup libavf
2655	* @{
2656	*
2657	* Miscellaneous utility functions related to both muxing and demuxing
2658	* (or neither).
2659	*/
2660
2661	/**
2662	* Send a nice hexadecimal dump of a buffer to the specified file stream.
2663	*
2664	* @param f The file stream pointer where the dump should be sent to.
2665	* @param buf buffer
2666	* @param size buffer size
2667	*
2668	* @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
2669	*/
2670	void av_hex_dump(FILE *f, const uint8_t *buf, int size);
2671
2672	/**
2673	* Send a nice hexadecimal dump of a buffer to the log.
2674	*
2675	* @param avcl A pointer to an arbitrary struct of which the first field is a
2676	* pointer to an AVClass struct.
2677	* @param level The importance level of the message, lower values signifying
2678	* higher importance.
2679	* @param buf buffer
2680	* @param size buffer size
2681	*
2682	* @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
2683	*/
2684	void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
2685
2686	/**
2687	* Send a nice dump of a packet to the specified file stream.
2688	*
2689	* @param f The file stream pointer where the dump should be sent to.
2690	* @param pkt packet to dump
2691	* @param dump_payload True if the payload must be displayed, too.
2692	* @param st AVStream that the packet belongs to
2693	*/
2694	void av_pkt_dump2(FILE *f, const AVPacket *pkt, int dump_payload, const AVStream *st);
2695
2696
2697	/**
2698	* Send a nice dump of a packet to the log.
2699	*
2700	* @param avcl A pointer to an arbitrary struct of which the first field is a
2701	* pointer to an AVClass struct.
2702	* @param level The importance level of the message, lower values signifying
2703	* higher importance.
2704	* @param pkt packet to dump
2705	* @param dump_payload True if the payload must be displayed, too.
2706	* @param st AVStream that the packet belongs to
2707	*/
2708	void av_pkt_dump_log2(void *avcl, int level, const AVPacket *pkt, int dump_payload,
2709	const AVStream *st);
2710
2711	/**
2712	* Get the AVCodecID for the given codec tag tag.
2713	* If no codec id is found returns AV_CODEC_ID_NONE.
2714	*
2715	* @param tags list of supported codec_id-codec_tag pairs, as stored
2716	* in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2717	* @param tag codec tag to match to a codec ID
2718	*/
2719	enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
2720
2721	/**
2722	* Get the codec tag for the given codec id id.
2723	* If no codec tag is found returns 0.
2724	*
2725	* @param tags list of supported codec_id-codec_tag pairs, as stored
2726	* in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2727	* @param id codec ID to match to a codec tag
2728	*/
2729	unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id);
2730
2731	/**
2732	* Get the codec tag for the given codec id.
2733	*
2734	* @param tags list of supported codec_id - codec_tag pairs, as stored
2735	* in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2736	* @param id codec id that should be searched for in the list
2737	* @param tag A pointer to the found tag
2738	* @return 0 if id was not found in tags, > 0 if it was found
2739	*/
2740	int av_codec_get_tag2(const struct AVCodecTag * const *tags, enum AVCodecID id,
2741	unsigned int *tag);
2742
2743	int av_find_default_stream_index(AVFormatContext *s);
2744
2745	/**
2746	* Get the index for a specific timestamp.
2747	*
2748	* @param st stream that the timestamp belongs to
2749	* @param timestamp timestamp to retrieve the index for
2750	* @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
2751	* to the timestamp which is <= the requested one, if backward
2752	* is 0, then it will be >=
2753	* if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
2754	* @return < 0 if no such timestamp could be found
2755	*/
2756	int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
2757
2758	/**
2759	* Add an index entry into a sorted list. Update the entry if the list
2760	* already contains it.
2761	*
2762	* @param timestamp timestamp in the time base of the given stream
2763	*/
2764	int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
2765	int size, int distance, int flags);
2766
2767
2768	/**
2769	* Split a URL string into components.
2770	*
2771	* The pointers to buffers for storing individual components may be null,
2772	* in order to ignore that component. Buffers for components not found are
2773	* set to empty strings. If the port is not found, it is set to a negative
2774	* value.
2775	*
2776	* @param proto the buffer for the protocol
2777	* @param proto_size the size of the proto buffer
2778	* @param authorization the buffer for the authorization
2779	* @param authorization_size the size of the authorization buffer
2780	* @param hostname the buffer for the host name
2781	* @param hostname_size the size of the hostname buffer
2782	* @param port_ptr a pointer to store the port number in
2783	* @param path the buffer for the path
2784	* @param path_size the size of the path buffer
2785	* @param url the URL to split
2786	*/
2787	void av_url_split(char *proto, int proto_size,
2788	char *authorization, int authorization_size,
2789	char *hostname, int hostname_size,
2790	int *port_ptr,
2791	char *path, int path_size,
2792	const char *url);
2793
2794
2795	/**
2796	* Print detailed information about the input or output format, such as
2797	* duration, bitrate, streams, container, programs, metadata, side data,
2798	* codec and time base.
2799	*
2800	* @param ic the context to analyze
2801	* @param index index of the stream to dump information about
2802	* @param url the URL to print, such as source or destination file
2803	* @param is_output Select whether the specified context is an input(0) or output(1)
2804	*/
2805	void av_dump_format(AVFormatContext *ic,
2806	int index,
2807	const char *url,
2808	int is_output);
2809
2810
2811	#define AV_FRAME_FILENAME_FLAGS_MULTIPLE 1 ///< Allow multiple %d
2812
2813	/**
2814	* Return in 'buf' the path with '%d' replaced by a number.
2815	*
2816	* Also handles the '%0nd' format where 'n' is the total number
2817	* of digits and '%%'.
2818	*
2819	* @param buf destination buffer
2820	* @param buf_size destination buffer size
2821	* @param path numbered sequence string
2822	* @param number frame number
2823	* @param flags AV_FRAME_FILENAME_FLAGS_*
2824	* @return 0 if OK, -1 on format error
2825	*/
2826	int av_get_frame_filename2(char *buf, int buf_size,
2827	const char *path, int number, int flags);
2828
2829	int av_get_frame_filename(char *buf, int buf_size,
2830	const char *path, int number);
2831
2832	/**
2833	* Check whether filename actually is a numbered sequence generator.
2834	*
2835	* @param filename possible numbered sequence string
2836	* @return 1 if a valid numbered sequence string, 0 otherwise
2837	*/
2838	int av_filename_number_test(const char *filename);
2839
2840	/**
2841	* Generate an SDP for an RTP session.
2842	*
2843	* Note, this overwrites the id values of AVStreams in the muxer contexts
2844	* for getting unique dynamic payload types.
2845	*
2846	* @param ac array of AVFormatContexts describing the RTP streams. If the
2847	* array is composed by only one context, such context can contain
2848	* multiple AVStreams (one AVStream per RTP stream). Otherwise,
2849	* all the contexts in the array (an AVCodecContext per RTP stream)
2850	* must contain only one AVStream.
2851	* @param n_files number of AVCodecContexts contained in ac
2852	* @param buf buffer where the SDP will be stored (must be allocated by
2853	* the caller)
2854	* @param size the size of the buffer
2855	* @return 0 if OK, AVERROR_xxx on error
2856	*/
2857	int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
2858
2859	/**
2860	* Return a positive value if the given filename has one of the given
2861	* extensions, 0 otherwise.
2862	*
2863	* @param filename file name to check against the given extensions
2864	* @param extensions a comma-separated list of filename extensions
2865	*/
2866	int av_match_ext(const char *filename, const char *extensions);
2867
2868	/**
2869	* Test if the given container can store a codec.
2870	*
2871	* @param ofmt container to check for compatibility
2872	* @param codec_id codec to potentially store in container
2873	* @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
2874	*
2875	* @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
2876	* A negative number if this information is not available.
2877	*/
2878	int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id,
2879	int std_compliance);
2880
2881	/**
2882	* @defgroup riff_fourcc RIFF FourCCs
2883	* @{
2884	* Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
2885	* meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
2886	* following code:
2887	* @code
2888	* uint32_t tag = MKTAG('H', '2', '6', '4');
2889	* const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
2890	* enum AVCodecID id = av_codec_get_id(table, tag);
2891	* @endcode
2892	*/
2893	/**
2894	* @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
2895	*/
2896	const struct AVCodecTag *avformat_get_riff_video_tags(void);
2897	/**
2898	* @return the table mapping RIFF FourCCs for audio to AVCodecID.
2899	*/
2900	const struct AVCodecTag *avformat_get_riff_audio_tags(void);
2901	/**
2902	* @return the table mapping MOV FourCCs for video to libavcodec AVCodecID.
2903	*/
2904	const struct AVCodecTag *avformat_get_mov_video_tags(void);
2905	/**
2906	* @return the table mapping MOV FourCCs for audio to AVCodecID.
2907	*/
2908	const struct AVCodecTag *avformat_get_mov_audio_tags(void);
2909
2910	/**
2911	* @}
2912	*/
2913
2914	/**
2915	* Guess the sample aspect ratio of a frame, based on both the stream and the
2916	* frame aspect ratio.
2917	*
2918	* Since the frame aspect ratio is set by the codec but the stream aspect ratio
2919	* is set by the demuxer, these two may not be equal. This function tries to
2920	* return the value that you should use if you would like to display the frame.
2921	*
2922	* Basic logic is to use the stream aspect ratio if it is set to something sane
2923	* otherwise use the frame aspect ratio. This way a container setting, which is
2924	* usually easy to modify can override the coded value in the frames.
2925	*
2926	* @param format the format context which the stream is part of
2927	* @param stream the stream which the frame is part of
2928	* @param frame the frame with the aspect ratio to be determined
2929	* @return the guessed (valid) sample_aspect_ratio, 0/1 if no idea
2930	*/
2931	AVRational av_guess_sample_aspect_ratio(AVFormatContext *format, AVStream *stream, AVFrame *frame);
2932
2933	/**
2934	* Guess the frame rate, based on both the container and codec information.
2935	*
2936	* @param ctx the format context which the stream is part of
2937	* @param stream the stream which the frame is part of
2938	* @param frame the frame for which the frame rate should be determined, may be NULL
2939	* @return the guessed (valid) frame rate, 0/1 if no idea
2940	*/
2941	AVRational av_guess_frame_rate(AVFormatContext *ctx, AVStream *stream, AVFrame *frame);
2942
2943	/**
2944	* Check if the stream st contained in s is matched by the stream specifier
2945	* spec.
2946	*
2947	* See the "stream specifiers" chapter in the documentation for the syntax
2948	* of spec.
2949	*
2950	* @return >0 if st is matched by spec;
2951	* 0 if st is not matched by spec;
2952	* AVERROR code if spec is invalid
2953	*
2954	* @note A stream specifier can match several streams in the format.
2955	*/
2956	int avformat_match_stream_specifier(AVFormatContext *s, AVStream *st,
2957	const char *spec);
2958
2959	int avformat_queue_attached_pictures(AVFormatContext *s);
2960
2961	#if FF_API_OLD_BSF
2962	/**
2963	* Apply a list of bitstream filters to a packet.
2964	*
2965	* @param codec AVCodecContext, usually from an AVStream
2966	* @param pkt the packet to apply filters to. If, on success, the returned
2967	* packet has size == 0 and side_data_elems == 0, it indicates that
2968	* the packet should be dropped
2969	* @param bsfc a NULL-terminated list of filters to apply
2970	* @return >=0 on success;
2971	* AVERROR code on failure
2972	*/
2973	attribute_deprecated
2974	int av_apply_bitstream_filters(AVCodecContext *codec, AVPacket *pkt,
2975	AVBitStreamFilterContext *bsfc);
2976	#endif
2977
2978	enum AVTimebaseSource {
2979	AVFMT_TBCF_AUTO = -1,
2980	AVFMT_TBCF_DECODER,
2981	AVFMT_TBCF_DEMUXER,
2982	#if FF_API_R_FRAME_RATE
2983	AVFMT_TBCF_R_FRAMERATE,
2984	#endif
2985	};
2986
2987	/**
2988	* Transfer internal timing information from one stream to another.
2989	*
2990	* This function is useful when doing stream copy.
2991	*
2992	* @param ofmt target output format for ost
2993	* @param ost output stream which needs timings copy and adjustments
2994	* @param ist reference input stream to copy timings from
2995	* @param copy_tb define from where the stream codec timebase needs to be imported
2996	*/
2997	int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
2998	AVStream *ost, const AVStream *ist,
2999	enum AVTimebaseSource copy_tb);
3000
3001	/**
3002	* Get the internal codec timebase from a stream.
3003	*
3004	* @param st input stream to extract the timebase from
3005	*/
3006	AVRational av_stream_get_codec_timebase(const AVStream *st);
3007
3008	/**
3009	* @}
3010	*/
3011
3012	#endif /* AVFORMAT_AVFORMAT_H */
3013