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

1	/*
2	* copyright (c) 2001 Fabrice Bellard
3	*
4	* This file is part of FFmpeg.
5	*
6	* FFmpeg is free software; you can redistribute it and/or
7	* modify it under the terms of the GNU Lesser General Public
8	* License as published by the Free Software Foundation; either
9	* version 2.1 of the License, or (at your option) any later version.
10	*
11	* FFmpeg is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14	* Lesser General Public License for more details.
15	*
16	* You should have received a copy of the GNU Lesser General Public
17	* License along with FFmpeg; if not, write to the Free Software
18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19	*/
20
21	#ifndef AVFORMAT_AVFORMAT_H
22	#define AVFORMAT_AVFORMAT_H
23
24	/**
25	* @file
26	* @ingroup libavf
27	* Main libavformat public API header
28	*/
29
30	/**
31	* @defgroup libavf libavformat
32	* I/O and Muxing/Demuxing Library
33	*
34	* Libavformat (lavf) is a library for dealing with various media container
35	* formats. Its main two purposes are demuxing - i.e. splitting a media file
36	* into component streams, and the reverse process of muxing - writing supplied
37	* data in a specified container format. It also has an @ref lavf_io
38	* "I/O module" which supports a number of protocols for accessing the data (e.g.
39	* file, tcp, http and others).
40	* Unless you are absolutely sure you won't use libavformat's network
41	* capabilities, you should also call avformat_network_init().
42	*
43	* A supported input format is described by an AVInputFormat struct, conversely
44	* an output format is described by AVOutputFormat. You can iterate over all
45	* input/output formats using the av_demuxer_iterate / av_muxer_iterate() functions.
46	* The protocols layer is not part of the public API, so you can only get the names
47	* of supported protocols with the avio_enum_protocols() function.
48	*
49	* Main lavf structure used for both muxing and demuxing is AVFormatContext,
50	* which exports all information about the file being read or written. As with
51	* most Libavformat structures, its size is not part of public ABI, so it cannot be
52	* allocated on stack or directly with av_malloc(). To create an
53	* AVFormatContext, use avformat_alloc_context() (some functions, like
54	* avformat_open_input() might do that for you).
55	*
56	* Most importantly an AVFormatContext contains:
57	* @li the @ref AVFormatContext.iformat "input" or @ref AVFormatContext.oformat
58	* "output" format. It is either autodetected or set by user for input;
59	* always set by user for output.
60	* @li an @ref AVFormatContext.streams "array" of AVStreams, which describe all
61	* elementary streams stored in the file. AVStreams are typically referred to
62	* using their index in this array.
63	* @li an @ref AVFormatContext.pb "I/O context". It is either opened by lavf or
64	* set by user for input, always set by user for output (unless you are dealing
65	* with an AVFMT_NOFILE format).
66	*
67	* @section lavf_options Passing options to (de)muxers
68	* It is possible to configure lavf muxers and demuxers using the @ref avoptions
69	* mechanism. Generic (format-independent) libavformat options are provided by
70	* AVFormatContext, they can be examined from a user program by calling
71	* av_opt_next() / av_opt_find() on an allocated AVFormatContext (or its AVClass
72	* from avformat_get_class()). Private (format-specific) options are provided by
73	* AVFormatContext.priv_data if and only if AVInputFormat.priv_class /
74	* AVOutputFormat.priv_class of the corresponding format struct is non-NULL.
75	* Further options may be provided by the @ref AVFormatContext.pb "I/O context",
76	* if its AVClass is non-NULL, and the protocols layer. See the discussion on
77	* nesting in @ref avoptions documentation to learn how to access those.
78	*
79	* @section urls
80	* URL strings in libavformat are made of a scheme/protocol, a ':', and a
81	* scheme specific string. URLs without a scheme and ':' used for local files
82	* are supported but deprecated. "file:" should be used for local files.
83	*
84	* It is important that the scheme string is not taken from untrusted
85	* sources without checks.
86	*
87	* Note that some schemes/protocols are quite powerful, allowing access to
88	* both local and remote files, parts of them, concatenations of them, local
89	* audio and video devices and so on.
90	*
91	* @{
92	*
93	* @defgroup lavf_decoding Demuxing
94	* @{
95	* Demuxers read a media file and split it into chunks of data (@em packets). A
96	* @ref AVPacket "packet" contains one or more encoded frames which belongs to a
97	* single elementary stream. In the lavf API this process is represented by the
98	* avformat_open_input() function for opening a file, av_read_frame() for
99	* reading a single packet and finally avformat_close_input(), which does the
100	* cleanup.
101	*
102	* @section lavf_decoding_open Opening a media file
103	* The minimum information required to open a file is its URL, which
104	* is passed to avformat_open_input(), as in the following code:
105	* @code
106	* const char *url = "file:in.mp3";
107	* AVFormatContext *s = NULL;
108	* int ret = avformat_open_input(&s, url, NULL, NULL);
109	* if (ret < 0)
110	* abort();
111	* @endcode
112	* The above code attempts to allocate an AVFormatContext, open the
113	* specified file (autodetecting the format) and read the header, exporting the
114	* information stored there into s. Some formats do not have a header or do not
115	* store enough information there, so it is recommended that you call the
116	* avformat_find_stream_info() function which tries to read and decode a few
117	* frames to find missing information.
118	*
119	* In some cases you might want to preallocate an AVFormatContext yourself with
120	* avformat_alloc_context() and do some tweaking on it before passing it to
121	* avformat_open_input(). One such case is when you want to use custom functions
122	* for reading input data instead of lavf internal I/O layer.
123	* To do that, create your own AVIOContext with avio_alloc_context(), passing
124	* your reading callbacks to it. Then set the @em pb field of your
125	* AVFormatContext to newly created AVIOContext.
126	*
127	* Since the format of the opened file is in general not known until after
128	* avformat_open_input() has returned, it is not possible to set demuxer private
129	* options on a preallocated context. Instead, the options should be passed to
130	* avformat_open_input() wrapped in an AVDictionary:
131	* @code
132	* AVDictionary *options = NULL;
133	* av_dict_set(&options, "video_size", "640x480", 0);
134	* av_dict_set(&options, "pixel_format", "rgb24", 0);
135	*
136	* if (avformat_open_input(&s, url, NULL, &options) < 0)
137	* abort();
138	* av_dict_free(&options);
139	* @endcode
140	* This code passes the private options 'video_size' and 'pixel_format' to the
141	* demuxer. They would be necessary for e.g. the rawvideo demuxer, since it
142	* cannot know how to interpret raw video data otherwise. If the format turns
143	* out to be something different than raw video, those options will not be
144	* recognized by the demuxer and therefore will not be applied. Such unrecognized
145	* options are then returned in the options dictionary (recognized options are
146	* consumed). The calling program can handle such unrecognized options as it
147	* wishes, e.g.
148	* @code
149	* const AVDictionaryEntry *e;
150	* if ((e = av_dict_iterate(options, NULL))) {
151	* fprintf(stderr, "Option %s not recognized by the demuxer.\n", e->key);
152	* abort();
153	* }
154	* @endcode
155	*
156	* After you have finished reading the file, you must close it with
157	* avformat_close_input(). It will free everything associated with the file.
158	*
159	* @section lavf_decoding_read Reading from an opened file
160	* Reading data from an opened AVFormatContext is done by repeatedly calling
161	* av_read_frame() on it. Each call, if successful, will return an AVPacket
162	* containing encoded data for one AVStream, identified by
163	* AVPacket.stream_index. This packet may be passed straight into the libavcodec
164	* decoding functions avcodec_send_packet() or avcodec_decode_subtitle2() if the
165	* caller wishes to decode the data.
166	*
167	* AVPacket.pts, AVPacket.dts and AVPacket.duration timing information will be
168	* set if known. They may also be unset (i.e. AV_NOPTS_VALUE for
169	* pts/dts, 0 for duration) if the stream does not provide them. The timing
170	* information will be in AVStream.time_base units, i.e. it has to be
171	* multiplied by the timebase to convert them to seconds.
172	*
173	* A packet returned by av_read_frame() is always reference-counted,
174	* i.e. AVPacket.buf is set and the user may keep it indefinitely.
175	* The packet must be freed with av_packet_unref() when it is no
176	* longer needed.
177	*
178	* @section lavf_decoding_seek Seeking
179	* @}
180	*
181	* @defgroup lavf_encoding Muxing
182	* @{
183	* Muxers take encoded data in the form of @ref AVPacket "AVPackets" and write
184	* it into files or other output bytestreams in the specified container format.
185	*
186	* The main API functions for muxing are avformat_write_header() for writing the
187	* file header, av_write_frame() / av_interleaved_write_frame() for writing the
188	* packets and av_write_trailer() for finalizing the file.
189	*
190	* At the beginning of the muxing process, the caller must first call
191	* avformat_alloc_context() to create a muxing context. The caller then sets up
192	* the muxer by filling the various fields in this context:
193	*
194	* - The @ref AVFormatContext.oformat "oformat" field must be set to select the
195	* muxer that will be used.
196	* - Unless the format is of the AVFMT_NOFILE type, the @ref AVFormatContext.pb
197	* "pb" field must be set to an opened IO context, either returned from
198	* avio_open2() or a custom one.
199	* - Unless the format is of the AVFMT_NOSTREAMS type, at least one stream must
200	* be created with the avformat_new_stream() function. The caller should fill
201	* the @ref AVStream.codecpar "stream codec parameters" information, such as the
202	* codec @ref AVCodecParameters.codec_type "type", @ref AVCodecParameters.codec_id
203	* "id" and other parameters (e.g. width / height, the pixel or sample format,
204	* etc.) as known. The @ref AVStream.time_base "stream timebase" should
205	* be set to the timebase that the caller desires to use for this stream (note
206	* that the timebase actually used by the muxer can be different, as will be
207	* described later).
208	* - It is advised to manually initialize only the relevant fields in
209	* AVCodecParameters, rather than using @ref avcodec_parameters_copy() during
210	* remuxing: there is no guarantee that the codec context values remain valid
211	* for both input and output format contexts.
212	* - The caller may fill in additional information, such as @ref
213	* AVFormatContext.metadata "global" or @ref AVStream.metadata "per-stream"
214	* metadata, @ref AVFormatContext.chapters "chapters", @ref
215	* AVFormatContext.programs "programs", etc. as described in the
216	* AVFormatContext documentation. Whether such information will actually be
217	* stored in the output depends on what the container format and the muxer
218	* support.
219	*
220	* When the muxing context is fully set up, the caller must call
221	* avformat_write_header() to initialize the muxer internals and write the file
222	* header. Whether anything actually is written to the IO context at this step
223	* depends on the muxer, but this function must always be called. Any muxer
224	* private options must be passed in the options parameter to this function.
225	*
226	* The data is then sent to the muxer by repeatedly calling av_write_frame() or
227	* av_interleaved_write_frame() (consult those functions' documentation for
228	* discussion on the difference between them; only one of them may be used with
229	* a single muxing context, they should not be mixed). Do note that the timing
230	* information on the packets sent to the muxer must be in the corresponding
231	* AVStream's timebase. That timebase is set by the muxer (in the
232	* avformat_write_header() step) and may be different from the timebase
233	* requested by the caller.
234	*
235	* Once all the data has been written, the caller must call av_write_trailer()
236	* to flush any buffered packets and finalize the output file, then close the IO
237	* context (if any) and finally free the muxing context with
238	* avformat_free_context().
239	* @}
240	*
241	* @defgroup lavf_io I/O Read/Write
242	* @{
243	* @section lavf_io_dirlist Directory listing
244	* The directory listing API makes it possible to list files on remote servers.
245	*
246	* Some of possible use cases:
247	* - an "open file" dialog to choose files from a remote location,
248	* - a recursive media finder providing a player with an ability to play all
249	* files from a given directory.
250	*
251	* @subsection lavf_io_dirlist_open Opening a directory
252	* At first, a directory needs to be opened by calling avio_open_dir()
253	* supplied with a URL and, optionally, ::AVDictionary containing
254	* protocol-specific parameters. The function returns zero or positive
255	* integer and allocates AVIODirContext on success.
256	*
257	* @code
258	* AVIODirContext *ctx = NULL;
259	* if (avio_open_dir(&ctx, "smb://example.com/some_dir", NULL) < 0) {
260	* fprintf(stderr, "Cannot open directory.\n");
261	* abort();
262	* }
263	* @endcode
264	*
265	* This code tries to open a sample directory using smb protocol without
266	* any additional parameters.
267	*
268	* @subsection lavf_io_dirlist_read Reading entries
269	* Each directory's entry (i.e. file, another directory, anything else
270	* within ::AVIODirEntryType) is represented by AVIODirEntry.
271	* Reading consecutive entries from an opened AVIODirContext is done by
272	* repeatedly calling avio_read_dir() on it. Each call returns zero or
273	* positive integer if successful. Reading can be stopped right after the
274	* NULL entry has been read -- it means there are no entries left to be
275	* read. The following code reads all entries from a directory associated
276	* with ctx and prints their names to standard output.
277	* @code
278	* AVIODirEntry *entry = NULL;
279	* for (;;) {
280	* if (avio_read_dir(ctx, &entry) < 0) {
281	* fprintf(stderr, "Cannot list directory.\n");
282	* abort();
283	* }
284	* if (!entry)
285	* break;
286	* printf("%s\n", entry->name);
287	* avio_free_directory_entry(&entry);
288	* }
289	* @endcode
290	* @}
291	*
292	* @defgroup lavf_codec Demuxers
293	* @{
294	* @defgroup lavf_codec_native Native Demuxers
295	* @{
296	* @}
297	* @defgroup lavf_codec_wrappers External library wrappers
298	* @{
299	* @}
300	* @}
301	* @defgroup lavf_protos I/O Protocols
302	* @{
303	* @}
304	* @defgroup lavf_internal Internal
305	* @{
306	* @}
307	* @}
308	*/
309
310	#include <stdio.h> /* FILE */
311
312	#include "libavcodec/codec_par.h"
313	#include "libavcodec/defs.h"
314	#include "libavcodec/packet.h"
315
316	#include "libavutil/dict.h"
317	#include "libavutil/log.h"
318
319	#include "avio.h"
320	#include "libavformat/version_major.h"
321	#ifndef HAVE_AV_CONFIG_H
322	/ When included as part of the ffmpeg build, only include the major version*
323	* to avoid unnecessary rebuilds. When included externally, keep including
324	* the full version information. */
325	#include "libavformat/version.h"
326
327	#include "libavutil/frame.h"
328	#include "libavcodec/codec.h"
329	#endif
330
331	struct AVFormatContext;
332	struct AVFrame;
333
334	/**
335	* @defgroup metadata_api Public Metadata API
336	* @{
337	* @ingroup libavf
338	* The metadata API allows libavformat to export metadata tags to a client
339	* application when demuxing. Conversely it allows a client application to
340	* set metadata when muxing.
341	*
342	* Metadata is exported or set as pairs of key/value strings in the 'metadata'
343	* fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
344	* using the @ref lavu_dict "AVDictionary" API. Like all strings in FFmpeg,
345	* metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
346	* exported by demuxers isn't checked to be valid UTF-8 in most cases.
347	*
348	* Important concepts to keep in mind:
349	* - Keys are unique; there can never be 2 tags with the same key. This is
350	* also meant semantically, i.e., a demuxer should not knowingly produce
351	* several keys that are literally different but semantically identical.
352	* E.g., key=Author5, key=Author6. In this example, all authors must be
353	* placed in the same tag.
354	* - Metadata is flat, not hierarchical; there are no subtags. If you
355	* want to store, e.g., the email address of the child of producer Alice
356	* and actor Bob, that could have key=alice_and_bobs_childs_email_address.
357	* - Several modifiers can be applied to the tag name. This is done by
358	* appending a dash character ('-') and the modifier name in the order
359	* they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
360	* - language -- a tag whose value is localized for a particular language
361	* is appended with the ISO 639-2/B 3-letter language code.
362	* For example: Author-ger=Michael, Author-eng=Mike
363	* The original/default language is in the unqualified "Author" tag.
364	* A demuxer should set a default if it sets any translated tag.
365	* - sorting -- a modified version of a tag that should be used for
366	* sorting will have '-sort' appended. E.g. artist="The Beatles",
367	* artist-sort="Beatles, The".
368	* - Some protocols and demuxers support metadata updates. After a successful
369	* call to av_read_frame(), AVFormatContext.event_flags or AVStream.event_flags
370	* will be updated to indicate if metadata changed. In order to detect metadata
371	* changes on a stream, you need to loop through all streams in the AVFormatContext
372	* and check their individual event_flags.
373	*
374	* - Demuxers attempt to export metadata in a generic format, however tags
375	* with no generic equivalents are left as they are stored in the container.
376	* Follows a list of generic tag names:
377	*
378	@verbatim
379	album -- name of the set this work belongs to
380	album_artist -- main creator of the set/album, if different from artist.
381	e.g. "Various Artists" for compilation albums.
382	artist -- main creator of the work
383	comment -- any additional description of the file.
384	composer -- who composed the work, if different from artist.
385	copyright -- name of copyright holder.
386	creation_time-- date when the file was created, preferably in ISO 8601.
387	date -- date when the work was created, preferably in ISO 8601.
388	disc -- number of a subset, e.g. disc in a multi-disc collection.
389	encoder -- name/settings of the software/hardware that produced the file.
390	encoded_by -- person/group who created the file.
391	filename -- original name of the file.
392	genre -- <self-evident>.
393	language -- main language in which the work is performed, preferably
394	in ISO 639-2 format. Multiple languages can be specified by
395	separating them with commas.
396	performer -- artist who performed the work, if different from artist.
397	E.g for "Also sprach Zarathustra", artist would be "Richard
398	Strauss" and performer "London Philharmonic Orchestra".
399	publisher -- name of the label/publisher.
400	service_name -- name of the service in broadcasting (channel name).
401	service_provider -- name of the service provider in broadcasting.
402	title -- name of the work.
403	track -- number of this work in the set, can be in form current/total.
404	variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
405	@endverbatim
406	*
407	* Look in the examples section for an application example how to use the Metadata API.
408	*
409	* @}
410	*/
411
412	/ packet functions /
413
414
415	/**
416	* Allocate and read the payload of a packet and initialize its
417	* fields with default values.
418	*
419	* @param s associated IO context
420	* @param pkt packet
421	* @param size desired payload size
422	* @return >0 (read size) if OK, AVERROR_xxx otherwise
423	*/
424	int av_get_packet(AVIOContext s, AVPacket pkt, int size);
425
426
427	/**
428	* Read data and append it to the current content of the AVPacket.
429	* If pkt->size is 0 this is identical to av_get_packet.
430	* Note that this uses av_grow_packet and thus involves a realloc
431	* which is inefficient. Thus this function should only be used
432	* when there is no reasonable way to know (an upper bound of)
433	* the final size.
434	*
435	* @param s associated IO context
436	* @param pkt packet
437	* @param size amount of data to read
438	* @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
439	* will not be lost even if an error occurs.
440	*/
441	int av_append_packet(AVIOContext s, AVPacket pkt, int size);
442
443	/***********************************************/
444	/ input/output formats /
445
446	struct AVCodecTag;
447
448	/**
449	* This structure contains the data a format has to probe a file.
450	*/
451	typedef struct AVProbeData {
452	const char *filename;
453	unsigned char buf; /*< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. /*
454	int buf_size; /< Size of buf except extra allocated bytes /*
455	const char mime_type; /*< mime_type, when known. /*
456	} AVProbeData;
457
458	#define AVPROBE_SCORE_RETRY (AVPROBE_SCORE_MAX/4)
459	#define AVPROBE_SCORE_STREAM_RETRY (AVPROBE_SCORE_MAX/4-1)
460
461	#define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
462	#define AVPROBE_SCORE_MIME_BONUS 30 ///< score added for matching mime type
463	#define AVPROBE_SCORE_MAX 100 ///< maximum score
464
465	#define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
466
467	/// Demuxer will use avio_open, no opened file should be provided by the caller.
468	#define AVFMT_NOFILE 0x0001
469	#define AVFMT_NEEDNUMBER 0x0002 /*< Needs '%d' in filename. /
470	/**
471	* The muxer/demuxer is experimental and should be used with caution.
472	*
473	* It will not be selected automatically, and must be specified explicitly.
474	*/
475	#define AVFMT_EXPERIMENTAL 0x0004
476	#define AVFMT_SHOW_IDS 0x0008 /*< Show format stream IDs numbers. /
477	#define AVFMT_GLOBALHEADER 0x0040 /*< Format wants global header. /
478	#define AVFMT_NOTIMESTAMPS 0x0080 /*< Format does not need / have any timestamps. /
479	#define AVFMT_GENERIC_INDEX 0x0100 /*< Use generic index building code. /
480	#define AVFMT_TS_DISCONT 0x0200 /*< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps /
481	#define AVFMT_VARIABLE_FPS 0x0400 /*< Format allows variable fps. /
482	#define AVFMT_NODIMENSIONS 0x0800 /*< Format does not need width/height /
483	#define AVFMT_NOSTREAMS 0x1000 /*< Format does not require any streams /
484	#define AVFMT_NOBINSEARCH 0x2000 /*< Format does not allow to fall back on binary search via read_timestamp /
485	#define AVFMT_NOGENSEARCH 0x4000 /*< Format does not allow to fall back on generic search /
486	#define AVFMT_NO_BYTE_SEEK 0x8000 /*< Format does not allow seeking by bytes /
487	#define AVFMT_TS_NONSTRICT 0x20000 /**< Format does not require strictly
488	increasing timestamps, but they must
489	still be monotonic */
490	#define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative
491	timestamps. If not set the timestamp
492	will be shifted in av_write_frame and
493	av_interleaved_write_frame so they
494	start from 0.
495	The user or muxer can override this through
496	AVFormatContext.avoid_negative_ts
497	*/
498
499	#define AVFMT_SEEK_TO_PTS 0x4000000 /*< Seeking is based on PTS /
500
501	/**
502	* @addtogroup lavf_encoding
503	* @{
504	*/
505	typedef struct AVOutputFormat {
506	const char *name;
507	/**
508	* Descriptive name for the format, meant to be more human-readable
509	* than name. You should use the NULL_IF_CONFIG_SMALL() macro
510	* to define it.
511	*/
512	const char *long_name;
513	const char *mime_type;
514	const char extensions; /*< comma-separated filename extensions /*
515	/ output support /
516	enum AVCodecID audio_codec; /< default audio codec /*
517	enum AVCodecID video_codec; /< default video codec /*
518	enum AVCodecID subtitle_codec; /< default subtitle codec /*
519	/**
520	* can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER,
521	* AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
522	* AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS,
523	* AVFMT_TS_NONSTRICT, AVFMT_TS_NEGATIVE
524	*/
525	int flags;
526
527	/**
528	* List of supported codec_id-codec_tag pairs, ordered by "better
529	* choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
530	*/
531	const struct AVCodecTag * const *codec_tag;
532
533
534	const AVClass priv_class; ///< AVClass for the private context*
535	} AVOutputFormat;
536	/**
537	* @}
538	*/
539
540	/**
541	* @addtogroup lavf_decoding
542	* @{
543	*/
544	typedef struct AVInputFormat {
545	/**
546	* A comma separated list of short names for the format. New names
547	* may be appended with a minor bump.
548	*/
549	const char *name;
550
551	/**
552	* Descriptive name for the format, meant to be more human-readable
553	* than name. You should use the NULL_IF_CONFIG_SMALL() macro
554	* to define it.
555	*/
556	const char *long_name;
557
558	/**
559	* Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
560	* AVFMT_NOTIMESTAMPS, AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
561	* AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK, AVFMT_SEEK_TO_PTS.
562	*/
563	int flags;
564
565	/**
566	* If extensions are defined, then no probe is done. You should
567	* usually not use extension format guessing because it is not
568	* reliable enough
569	*/
570	const char *extensions;
571
572	const struct AVCodecTag * const *codec_tag;
573
574	const AVClass priv_class; ///< AVClass for the private context*
575
576	/**
577	* Comma-separated list of mime types.
578	* It is used check for matching mime types while probing.
579	* @see av_probe_input_format2
580	*/
581	const char *mime_type;
582	} AVInputFormat;
583	/**
584	* @}
585	*/
586
587	enum AVStreamParseType {
588	AVSTREAM_PARSE_NONE,
589	AVSTREAM_PARSE_FULL, /< full parsing and repack /*
590	AVSTREAM_PARSE_HEADERS, /< Only parse headers, do not repack. /*
591	AVSTREAM_PARSE_TIMESTAMPS, /< full parsing and interpolation of timestamps for frames not starting on a packet boundary /*
592	AVSTREAM_PARSE_FULL_ONCE, /< full parsing and repack of the first frame only, only implemented for H.264 currently /*
593	AVSTREAM_PARSE_FULL_RAW, /< full parsing and repack with timestamp and position generation by parser for raw
594	this assumes that each packet in the file contains no demuxer level headers and
595	just codec level data, otherwise position generation would fail /*
596	};
597
598	typedef struct AVIndexEntry {
599	int64_t pos;
600	int64_t timestamp; /<
601	* Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are available
602	* when seeking to this entry. That means preferable PTS on keyframe based formats.
603	* But demuxers can choose to store a different timestamp, if it is more convenient for the implementation or nothing better
604	* is known
605	*/
606	#define AVINDEX_KEYFRAME 0x0001
607	#define AVINDEX_DISCARD_FRAME 0x0002 /**
608	* Flag is used to indicate which frame should be discarded after decoding.
609	*/
610	int flags:`2`;
611	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).
612	int min_distance; /< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. /*
613	} AVIndexEntry;
614
615	/**
616	* The stream should be chosen by default among other streams of the same type,
617	* unless the user has explicitly specified otherwise.
618	*/
619	#define AV_DISPOSITION_DEFAULT (1 << 0)
620	/**
621	* The stream is not in original language.
622	*
623	* @note AV_DISPOSITION_ORIGINAL is the inverse of this disposition. At most
624	* one of them should be set in properly tagged streams.
625	* @note This disposition may apply to any stream type, not just audio.
626	*/
627	#define AV_DISPOSITION_DUB (1 << 1)
628	/**
629	* The stream is in original language.
630	*
631	* @see the notes for AV_DISPOSITION_DUB
632	*/
633	#define AV_DISPOSITION_ORIGINAL (1 << 2)
634	/**
635	* The stream is a commentary track.
636	*/
637	#define AV_DISPOSITION_COMMENT (1 << 3)
638	/**
639	* The stream contains song lyrics.
640	*/
641	#define AV_DISPOSITION_LYRICS (1 << 4)
642	/**
643	* The stream contains karaoke audio.
644	*/
645	#define AV_DISPOSITION_KARAOKE (1 << 5)
646
647	/**
648	* Track should be used during playback by default.
649	* Useful for subtitle track that should be displayed
650	* even when user did not explicitly ask for subtitles.
651	*/
652	#define AV_DISPOSITION_FORCED (1 << 6)
653	/**
654	* The stream is intended for hearing impaired audiences.
655	*/
656	#define AV_DISPOSITION_HEARING_IMPAIRED (1 << 7)
657	/**
658	* The stream is intended for visually impaired audiences.
659	*/
660	#define AV_DISPOSITION_VISUAL_IMPAIRED (1 << 8)
661	/**
662	* The audio stream contains music and sound effects without voice.
663	*/
664	#define AV_DISPOSITION_CLEAN_EFFECTS (1 << 9)
665	/**
666	* The stream is stored in the file as an attached picture/"cover art" (e.g.
667	* APIC frame in ID3v2). The first (usually only) packet associated with it
668	* will be returned among the first few packets read from the file unless
669	* seeking takes place. It can also be accessed at any time in
670	* AVStream.attached_pic.
671	*/
672	#define AV_DISPOSITION_ATTACHED_PIC (1 << 10)
673	/**
674	* The stream is sparse, and contains thumbnail images, often corresponding
675	* to chapter markers. Only ever used with AV_DISPOSITION_ATTACHED_PIC.
676	*/
677	#define AV_DISPOSITION_TIMED_THUMBNAILS (1 << 11)
678
679	/**
680	* The stream is intended to be mixed with a spatial audio track. For example,
681	* it could be used for narration or stereo music, and may remain unchanged by
682	* listener head rotation.
683	*/
684	#define AV_DISPOSITION_NON_DIEGETIC (1 << 12)
685
686	/**
687	* The subtitle stream contains captions, providing a transcription and possibly
688	* a translation of audio. Typically intended for hearing-impaired audiences.
689	*/
690	#define AV_DISPOSITION_CAPTIONS (1 << 16)
691	/**
692	* The subtitle stream contains a textual description of the video content.
693	* Typically intended for visually-impaired audiences or for the cases where the
694	* video cannot be seen.
695	*/
696	#define AV_DISPOSITION_DESCRIPTIONS (1 << 17)
697	/**
698	* The subtitle stream contains time-aligned metadata that is not intended to be
699	* directly presented to the user.
700	*/
701	#define AV_DISPOSITION_METADATA (1 << 18)
702	/**
703	* The stream is intended to be mixed with another stream before presentation.
704	* Used for example to signal the stream contains an image part of a HEIF grid,
705	* or for mix_type=0 in mpegts.
706	*/
707	#define AV_DISPOSITION_DEPENDENT (1 << 19)
708	/**
709	* The video stream contains still images.
710	*/
711	#define AV_DISPOSITION_STILL_IMAGE (1 << 20)
712	/**
713	* The video stream contains multiple layers, e.g. stereoscopic views (cf. H.264
714	* Annex G/H, or HEVC Annex F).
715	*/
716	#define AV_DISPOSITION_MULTILAYER (1 << 21)
717
718	/**
719	* @return The AV_DISPOSITION_* flag corresponding to disp or a negative error
720	* code if disp does not correspond to a known stream disposition.
721	*/
722	int av_disposition_from_string(const char *disp);
723
724	/**
725	* @param disposition a combination of AV_DISPOSITION_* values
726	* @return The string description corresponding to the lowest set bit in
727	* disposition. NULL when the lowest set bit does not correspond
728	* to a known disposition or when disposition is 0.
729	*/
730	const char av_disposition_to_string(int* disposition);
731
732	/**
733	* Options for behavior on timestamp wrap detection.
734	*/
735	#define AV_PTS_WRAP_IGNORE 0 ///< ignore the wrap
736	#define AV_PTS_WRAP_ADD_OFFSET 1 ///< add the format specific offset on wrap detection
737	#define AV_PTS_WRAP_SUB_OFFSET -1 ///< subtract the format specific offset on wrap detection
738
739	/**
740	* Stream structure.
741	* New fields can be added to the end with minor version bumps.
742	* Removal, reordering and changes to existing fields require a major
743	* version bump.
744	* sizeof(AVStream) must not be used outside libav*.
745	*/
746	typedef struct AVStream {
747	/**
748	* A class for @ref avoptions. Set on stream creation.
749	*/
750	const AVClass *av_class;
751
752	int index; /< stream index in AVFormatContext /*
753	/**
754	* Format-specific stream ID.
755	* decoding: set by libavformat
756	* encoding: set by the user, replaced by libavformat if left unset
757	*/
758	int id;
759
760	/**
761	* Codec parameters associated with this stream. Allocated and freed by
762	* libavformat in avformat_new_stream() and avformat_free_context()
763	* respectively.
764	*
765	* - demuxing: filled by libavformat on stream creation or in
766	* avformat_find_stream_info()
767	* - muxing: filled by the caller before avformat_write_header()
768	*/
769	AVCodecParameters *codecpar;
770
771	void *priv_data;
772
773	/**
774	* This is the fundamental unit of time (in seconds) in terms
775	* of which frame timestamps are represented.
776	*
777	* decoding: set by libavformat
778	* encoding: May be set by the caller before avformat_write_header() to
779	* provide a hint to the muxer about the desired timebase. In
780	* avformat_write_header(), the muxer will overwrite this field
781	* with the timebase that will actually be used for the timestamps
782	* written into the file (which may or may not be related to the
783	* user-provided one, depending on the format).
784	*/
785	AVRational time_base;
786
787	/**
788	* Decoding: pts of the first frame of the stream in presentation order, in stream time base.
789	* Only set this if you are absolutely 100% sure that the value you set
790	* it to really is the pts of the first frame.
791	* This may be undefined (AV_NOPTS_VALUE).
792	* @note The ASF header does NOT contain a correct start_time the ASF
793	* demuxer must NOT set this.
794	*/
795	int64_t start_time;
796
797	/**
798	* Decoding: duration of the stream, in stream time base.
799	* If a source file does not specify a duration, but does specify
800	* a bitrate, this value will be estimated from bitrate and file size.
801	*
802	* Encoding: May be set by the caller before avformat_write_header() to
803	* provide a hint to the muxer about the estimated duration.
804	*/
805	int64_t duration;
806
807	int64_t nb_frames; ///< number of frames in this stream if known or 0
808
809	/**
810	* Stream disposition - a combination of AV_DISPOSITION_* flags.
811	* - demuxing: set by libavformat when creating the stream or in
812	* avformat_find_stream_info().
813	* - muxing: may be set by the caller before avformat_write_header().
814	*/
815	int disposition;
816
817	enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
818
819	/**
820	* sample aspect ratio (0 if unknown)
821	* - encoding: Set by user.
822	* - decoding: Set by libavformat.
823	*/
824	AVRational sample_aspect_ratio;
825
826	AVDictionary *metadata;
827
828	/**
829	* Average framerate
830	*
831	* - demuxing: May be set by libavformat when creating the stream or in
832	* avformat_find_stream_info().
833	* - muxing: May be set by the caller before avformat_write_header().
834	*/
835	AVRational avg_frame_rate;
836
837	/**
838	* For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
839	* will contain the attached picture.
840	*
841	* decoding: set by libavformat, must not be modified by the caller.
842	* encoding: unused
843	*/
844	AVPacket attached_pic;
845
846	/**
847	* Flags indicating events happening on the stream, a combination of
848	* AVSTREAM_EVENT_FLAG_*.
849	*
850	* - demuxing: may be set by the demuxer in avformat_open_input(),
851	* avformat_find_stream_info() and av_read_frame(). Flags must be cleared
852	* by the user once the event has been handled.
853	* - muxing: may be set by the user after avformat_write_header(). to
854	* indicate a user-triggered event. The muxer will clear the flags for
855	* events it has handled in av_[interleaved]_write_frame().
856	*/
857	int event_flags;
858	/**
859	* - demuxing: the demuxer read new metadata from the file and updated
860	* AVStream.metadata accordingly
861	* - muxing: the user updated AVStream.metadata and wishes the muxer to write
862	* it into the file
863	*/
864	#define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001
865	/**
866	* - demuxing: new packets for this stream were read from the file. This
867	* event is informational only and does not guarantee that new packets
868	* for this stream will necessarily be returned from av_read_frame().
869	*/
870	#define AVSTREAM_EVENT_FLAG_NEW_PACKETS (1 << 1)
871
872	/**
873	* Real base framerate of the stream.
874	* This is the lowest framerate with which all timestamps can be
875	* represented accurately (it is the least common multiple of all
876	* framerates in the stream). Note, this value is just a guess!
877	* For example, if the time base is 1/90000 and all frames have either
878	* approximately 3600 or 1800 timer ticks, then r_frame_rate will be 50/1.
879	*/
880	AVRational r_frame_rate;
881
882	/**
883	* Number of bits in timestamps. Used for wrapping control.
884	*
885	* - demuxing: set by libavformat
886	* - muxing: set by libavformat
887	*
888	*/
889	int pts_wrap_bits;
890	} AVStream;
891
892	/**
893	* AVStreamGroupTileGrid holds information on how to combine several
894	* independent images on a single canvas for presentation.
895	*
896	* The output should be a @ref AVStreamGroupTileGrid.background "background"
897	* colored @ref AVStreamGroupTileGrid.coded_width "coded_width" x
898	* @ref AVStreamGroupTileGrid.coded_height "coded_height" canvas where a
899	* @ref AVStreamGroupTileGrid.nb_tiles "nb_tiles" amount of tiles are placed in
900	* the order they appear in the @ref AVStreamGroupTileGrid.offsets "offsets"
901	* array, at the exact offset described for them. In particular, if two or more
902	* tiles overlap, the image with higher index in the
903	* @ref AVStreamGroupTileGrid.offsets "offsets" array takes priority.
904	* Note that a single image may be used multiple times, i.e. multiple entries
905	* in @ref AVStreamGroupTileGrid.offsets "offsets" may have the same value of
906	* idx.
907	*
908	* The following is an example of a simple grid with 3 rows and 4 columns:
909	*
910	* +---+---+---+---+
911	* \| 0 \| 1 \| 2 \| 3 \|
912	* +---+---+---+---+
913	* \| 4 \| 5 \| 6 \| 7 \|
914	* +---+---+---+---+
915	* \| 8 \| 9 \|10 \|11 \|
916	* +---+---+---+---+
917	*
918	* Assuming all tiles have a dimension of 512x512, the
919	* @ref AVStreamGroupTileGrid.offsets "offset" of the topleft pixel of
920	* the first @ref AVStreamGroup.streams "stream" in the group is "0,0", the
921	* @ref AVStreamGroupTileGrid.offsets "offset" of the topleft pixel of
922	* the second @ref AVStreamGroup.streams "stream" in the group is "512,0", the
923	* @ref AVStreamGroupTileGrid.offsets "offset" of the topleft pixel of
924	* the fifth @ref AVStreamGroup.streams "stream" in the group is "0,512", the
925	* @ref AVStreamGroupTileGrid.offsets "offset", of the topleft pixel of
926	* the sixth @ref AVStreamGroup.streams "stream" in the group is "512,512",
927	* etc.
928	*
929	* The following is an example of a canvas with overlapping tiles:
930	*
931	* +-----------+
932	* \| %%%%% \|
933	* \|***%%3%%@@@\|
934	* \|**0%%%%%2@@\|
935	* \|***##1@@@@@\|
936	* \| ##### \|
937	* +-----------+
938	*
939	* Assuming a canvas with size 1024x1024 and all tiles with a dimension of
940	* 512x512, a possible @ref AVStreamGroupTileGrid.offsets "offset" for the
941	* topleft pixel of the first @ref AVStreamGroup.streams "stream" in the group
942	* would be 0x256, the @ref AVStreamGroupTileGrid.offsets "offset" for the
943	* topleft pixel of the second @ref AVStreamGroup.streams "stream" in the group
944	* would be 256x512, the @ref AVStreamGroupTileGrid.offsets "offset" for the
945	* topleft pixel of the third @ref AVStreamGroup.streams "stream" in the group
946	* would be 512x256, and the @ref AVStreamGroupTileGrid.offsets "offset" for
947	* the topleft pixel of the fourth @ref AVStreamGroup.streams "stream" in the
948	* group would be 256x0.
949	*
950	* sizeof(AVStreamGroupTileGrid) is not a part of the ABI and may only be
951	* allocated by avformat_stream_group_create().
952	*/
953	typedef struct AVStreamGroupTileGrid {
954	const AVClass *av_class;
955
956	/**
957	* Amount of tiles in the grid.
958	*
959	* Must be > 0.
960	*/
961	unsigned int nb_tiles;
962
963	/**
964	* Width of the canvas.
965	*
966	* Must be > 0.
967	*/
968	int coded_width;
969	/**
970	* Width of the canvas.
971	*
972	* Must be > 0.
973	*/
974	int coded_height;
975
976	/**
977	* An @ref nb_tiles sized array of offsets in pixels from the topleft edge
978	* of the canvas, indicating where each stream should be placed.
979	* It must be allocated with the av_malloc() family of functions.
980	*
981	* - demuxing: set by libavformat, must not be modified by the caller.
982	* - muxing: set by the caller before avformat_write_header().
983	*
984	* Freed by libavformat in avformat_free_context().
985	*/
986	struct {
987	/**
988	* Index of the stream in the group this tile references.
989	*
990	* Must be < @ref AVStreamGroup.nb_streams "nb_streams".
991	*/
992	unsigned int idx;
993	/**
994	* Offset in pixels from the left edge of the canvas where the tile
995	* should be placed.
996	*/
997	int horizontal;
998	/**
999	* Offset in pixels from the top edge of the canvas where the tile
1000	* should be placed.
1001	*/
1002	int vertical;
1003	} *offsets;
1004
1005	/**
1006	* The pixel value per channel in RGBA format used if no pixel of any tile
1007	* is located at a particular pixel location.
1008	*
1009	* @see av_image_fill_color().
1010	* @see av_parse_color().
1011	*/
1012	uint8_t background[`4`];
1013
1014	/**
1015	* Offset in pixels from the left edge of the canvas where the actual image
1016	* meant for presentation starts.
1017	*
1018	* This field must be >= 0 and < @ref coded_width.
1019	*/
1020	int horizontal_offset;
1021	/**
1022	* Offset in pixels from the top edge of the canvas where the actual image
1023	* meant for presentation starts.
1024	*
1025	* This field must be >= 0 and < @ref coded_height.
1026	*/
1027	int vertical_offset;
1028
1029	/**
1030	* Width of the final image for presentation.
1031	*
1032	* Must be > 0 and <= (@ref coded_width - @ref horizontal_offset).
1033	* When it's not equal to (@ref coded_width - @ref horizontal_offset), the
1034	* result of (@ref coded_width - width - @ref horizontal_offset) is the
1035	* amount amount of pixels to be cropped from the right edge of the
1036	* final image before presentation.
1037	*/
1038	int width;
1039	/**
1040	* Height of the final image for presentation.
1041	*
1042	* Must be > 0 and <= (@ref coded_height - @ref vertical_offset).
1043	* When it's not equal to (@ref coded_height - @ref vertical_offset), the
1044	* result of (@ref coded_height - height - @ref vertical_offset) is the
1045	* amount amount of pixels to be cropped from the bottom edge of the
1046	* final image before presentation.
1047	*/
1048	int height;
1049
1050	/**
1051	* Additional data associated with the grid.
1052	*
1053	* Should be allocated with av_packet_side_data_new() or
1054	* av_packet_side_data_add(), and will be freed by avformat_free_context().
1055	*/
1056	AVPacketSideData *coded_side_data;
1057
1058	/**
1059	* Amount of entries in @ref coded_side_data.
1060	*/
1061	int nb_coded_side_data;
1062	} AVStreamGroupTileGrid;
1063
1064	/**
1065	* AVStreamGroupLCEVC is meant to define the relation between video streams
1066	* and a data stream containing LCEVC enhancement layer NALUs.
1067	*
1068	* No more than one stream of
1069	* @ref AVCodecParameters.codec_id "codec_id" AV_CODEC_ID_LCEVC shall be present.
1070	*/
1071	typedef struct AVStreamGroupLCEVC {
1072	const AVClass *av_class;
1073
1074	/**
1075	* Index of the LCEVC data stream in AVStreamGroup.
1076	*/
1077	unsigned int lcevc_index;
1078	/**
1079	* Width of the final stream for presentation.
1080	*/
1081	int width;
1082	/**
1083	* Height of the final image for presentation.
1084	*/
1085	int height;
1086	} AVStreamGroupLCEVC;
1087
1088	enum AVStreamGroupParamsType {
1089	AV_STREAM_GROUP_PARAMS_NONE,
1090	AV_STREAM_GROUP_PARAMS_IAMF_AUDIO_ELEMENT,
1091	AV_STREAM_GROUP_PARAMS_IAMF_MIX_PRESENTATION,
1092	AV_STREAM_GROUP_PARAMS_TILE_GRID,
1093	AV_STREAM_GROUP_PARAMS_LCEVC,
1094	};
1095
1096	struct AVIAMFAudioElement;
1097	struct AVIAMFMixPresentation;
1098
1099	typedef struct AVStreamGroup {
1100	/**
1101	* A class for @ref avoptions. Set by avformat_stream_group_create().
1102	*/
1103	const AVClass *av_class;
1104
1105	void *priv_data;
1106
1107	/**
1108	* Group index in AVFormatContext.
1109	*/
1110	unsigned int index;
1111
1112	/**
1113	* Group type-specific group ID.
1114	*
1115	* decoding: set by libavformat
1116	* encoding: may set by the user
1117	*/
1118	int64_t id;
1119
1120	/**
1121	* Group type
1122	*
1123	* decoding: set by libavformat on group creation
1124	* encoding: set by avformat_stream_group_create()
1125	*/
1126	enum AVStreamGroupParamsType type;
1127
1128	/**
1129	* Group type-specific parameters
1130	*/
1131	union {
1132	struct AVIAMFAudioElement *iamf_audio_element;
1133	struct AVIAMFMixPresentation *iamf_mix_presentation;
1134	struct AVStreamGroupTileGrid *tile_grid;
1135	struct AVStreamGroupLCEVC *lcevc;
1136	} params;
1137
1138	/**
1139	* Metadata that applies to the whole group.
1140	*
1141	* - demuxing: set by libavformat on group creation
1142	* - muxing: may be set by the caller before avformat_write_header()
1143	*
1144	* Freed by libavformat in avformat_free_context().
1145	*/
1146	AVDictionary *metadata;
1147
1148	/**
1149	* Number of elements in AVStreamGroup.streams.
1150	*
1151	* Set by avformat_stream_group_add_stream() must not be modified by any other code.
1152	*/
1153	unsigned int nb_streams;
1154
1155	/**
1156	* A list of streams in the group. New entries are created with
1157	* avformat_stream_group_add_stream().
1158	*
1159	* - demuxing: entries are created by libavformat on group creation.
1160	* If AVFMTCTX_NOHEADER is set in ctx_flags, then new entries may also
1161	* appear in av_read_frame().
1162	* - muxing: entries are created by the user before avformat_write_header().
1163	*
1164	* Freed by libavformat in avformat_free_context().
1165	*/
1166	AVStream **streams;
1167
1168	/**
1169	* Stream group disposition - a combination of AV_DISPOSITION_* flags.
1170	* This field currently applies to all defined AVStreamGroupParamsType.
1171	*
1172	* - demuxing: set by libavformat when creating the group or in
1173	* avformat_find_stream_info().
1174	* - muxing: may be set by the caller before avformat_write_header().
1175	*/
1176	int disposition;
1177	} AVStreamGroup;
1178
1179	struct AVCodecParserContext av_stream_get_parser(const* AVStream *s);
1180
1181	// Chromium: We use the internal field first_dts vvv
1182	int64_t av_stream_get_first_dts(const AVStream *st);
1183	// Chromium: We use the internal field first_dts ^^^
1184
1185	#define AV_PROGRAM_RUNNING 1
1186
1187	/**
1188	* New fields can be added to the end with minor version bumps.
1189	* Removal, reordering and changes to existing fields require a major
1190	* version bump.
1191	* sizeof(AVProgram) must not be used outside libav*.
1192	*/
1193	typedef struct AVProgram {
1194	int id;
1195	int flags;
1196	enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
1197	unsigned int *stream_index;
1198	unsigned int nb_stream_indexes;
1199	AVDictionary *metadata;
1200
1201	int program_num;
1202	int pmt_pid;
1203	int pcr_pid;
1204	int pmt_version;
1205
1206	/*****************************************************************
1207	* All fields below this line are not part of the public API. They
1208	* may not be used outside of libavformat and can be changed and
1209	* removed at will.
1210	* New public fields should be added right above.
1211	*****************************************************************
1212	*/
1213	int64_t start_time;
1214	int64_t end_time;
1215
1216	int64_t pts_wrap_reference; ///< reference dts for wrap detection
1217	int pts_wrap_behavior; ///< behavior on wrap detection
1218	} AVProgram;
1219
1220	#define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
1221	(streams are added dynamically) */
1222	#define AVFMTCTX_UNSEEKABLE 0x0002 /**< signal that the stream is definitely
1223	not seekable, and attempts to call the
1224	seek function will fail. For some
1225	network protocols (e.g. HLS), this can
1226	change dynamically at runtime. */
1227
1228	typedef struct AVChapter {
1229	int64_t id; ///< unique ID to identify the chapter
1230	AVRational time_base; ///< time base in which the start/end timestamps are specified
1231	int64_t start, end; ///< chapter start/end time in time_base units
1232	AVDictionary *metadata;
1233	} AVChapter;
1234
1235
1236	/**
1237	* Callback used by devices to communicate with application.
1238	*/
1239	typedef int (av_format_control_message)(struct* AVFormatContext s, int* type,
1240	void *data, size_t data_size);
1241
1242	typedef int (AVOpenCallback)(struct* AVFormatContext s, AVIOContext pb, const* char url, int* flags,
1243	const AVIOInterruptCB int_cb, AVDictionary *options);
1244
1245	/**
1246	* The duration of a video can be estimated through various ways, and this enum can be used
1247	* to know how the duration was estimated.
1248	*/
1249	enum AVDurationEstimationMethod {
1250	AVFMT_DURATION_FROM_PTS, ///< Duration accurately estimated from PTSes
1251	AVFMT_DURATION_FROM_STREAM, ///< Duration estimated from a stream with a known duration
1252	AVFMT_DURATION_FROM_BITRATE ///< Duration estimated from bitrate (less accurate)
1253	};
1254
1255	/**
1256	* Format I/O context.
1257	* New fields can be added to the end with minor version bumps.
1258	* Removal, reordering and changes to existing fields require a major
1259	* version bump.
1260	* sizeof(AVFormatContext) must not be used outside libav*, use
1261	* avformat_alloc_context() to create an AVFormatContext.
1262	*
1263	* Fields can be accessed through AVOptions (av_opt*),
1264	* the name string used matches the associated command line parameter name and
1265	* can be found in libavformat/options_table.h.
1266	* The AVOption/command line parameter names differ in some cases from the C
1267	* structure field names for historic reasons or brevity.
1268	*/
1269	typedef struct AVFormatContext {
1270	/**
1271	* A class for logging and @ref avoptions. Set by avformat_alloc_context().
1272	* Exports (de)muxer private options if they exist.
1273	*/
1274	const AVClass *av_class;
1275
1276	/**
1277	* The input container format.
1278	*
1279	* Demuxing only, set by avformat_open_input().
1280	*/
1281	const struct AVInputFormat *iformat;
1282
1283	/**
1284	* The output container format.
1285	*
1286	* Muxing only, must be set by the caller before avformat_write_header().
1287	*/
1288	const struct AVOutputFormat *oformat;
1289
1290	/**
1291	* Format private data. This is an AVOptions-enabled struct
1292	* if and only if iformat/oformat.priv_class is not NULL.
1293	*
1294	* - muxing: set by avformat_write_header()
1295	* - demuxing: set by avformat_open_input()
1296	*/
1297	void *priv_data;
1298
1299	/**
1300	* I/O context.
1301	*
1302	* - demuxing: either set by the user before avformat_open_input() (then
1303	* the user must close it manually) or set by avformat_open_input().
1304	* - muxing: set by the user before avformat_write_header(). The caller must
1305	* take care of closing / freeing the IO context.
1306	*
1307	* Do NOT set this field if AVFMT_NOFILE flag is set in
1308	* iformat/oformat.flags. In such a case, the (de)muxer will handle
1309	* I/O in some other way and this field will be NULL.
1310	*/
1311	AVIOContext *pb;
1312
1313	/ stream info /
1314	/**
1315	* Flags signalling stream properties. A combination of AVFMTCTX_*.
1316	* Set by libavformat.
1317	*/
1318	int ctx_flags;
1319
1320	/**
1321	* Number of elements in AVFormatContext.streams.
1322	*
1323	* Set by avformat_new_stream(), must not be modified by any other code.
1324	*/
1325	unsigned int nb_streams;
1326	/**
1327	* A list of all streams in the file. New streams are created with
1328	* avformat_new_stream().
1329	*
1330	* - demuxing: streams are created by libavformat in avformat_open_input().
1331	* If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
1332	* appear in av_read_frame().
1333	* - muxing: streams are created by the user before avformat_write_header().
1334	*
1335	* Freed by libavformat in avformat_free_context().
1336	*/
1337	AVStream **streams;
1338
1339	/**
1340	* Number of elements in AVFormatContext.stream_groups.
1341	*
1342	* Set by avformat_stream_group_create(), must not be modified by any other code.
1343	*/
1344	unsigned int nb_stream_groups;
1345	/**
1346	* A list of all stream groups in the file. New groups are created with
1347	* avformat_stream_group_create(), and filled with avformat_stream_group_add_stream().
1348	*
1349	* - demuxing: groups may be created by libavformat in avformat_open_input().
1350	* If AVFMTCTX_NOHEADER is set in ctx_flags, then new groups may also
1351	* appear in av_read_frame().
1352	* - muxing: groups may be created by the user before avformat_write_header().
1353	*
1354	* Freed by libavformat in avformat_free_context().
1355	*/
1356	AVStreamGroup **stream_groups;
1357
1358	/**
1359	* Number of chapters in AVChapter array.
1360	* When muxing, chapters are normally written in the file header,
1361	* so nb_chapters should normally be initialized before write_header
1362	* is called. Some muxers (e.g. mov and mkv) can also write chapters
1363	* in the trailer. To write chapters in the trailer, nb_chapters
1364	* must be zero when write_header is called and non-zero when
1365	* write_trailer is called.
1366	* - muxing: set by user
1367	* - demuxing: set by libavformat
1368	*/
1369	unsigned int nb_chapters;
1370	AVChapter **chapters;
1371
1372	/**
1373	* input or output URL. Unlike the old filename field, this field has no
1374	* length restriction.
1375	*
1376	* - demuxing: set by avformat_open_input(), initialized to an empty
1377	* string if url parameter was NULL in avformat_open_input().
1378	* - muxing: may be set by the caller before calling avformat_write_header()
1379	* (or avformat_init_output() if that is called first) to a string
1380	* which is freeable by av_free(). Set to an empty string if it
1381	* was NULL in avformat_init_output().
1382	*
1383	* Freed by libavformat in avformat_free_context().
1384	*/
1385	char *url;
1386
1387	/**
1388	* Position of the first frame of the component, in
1389	* AV_TIME_BASE fractional seconds. NEVER set this value directly:
1390	* It is deduced from the AVStream values.
1391	*
1392	* Demuxing only, set by libavformat.
1393	*/
1394	int64_t start_time;
1395
1396	/**
1397	* Duration of the stream, in AV_TIME_BASE fractional
1398	* seconds. Only set this value if you know none of the individual stream
1399	* durations and also do not set any of them. This is deduced from the
1400	* AVStream values if not set.
1401	*
1402	* Demuxing only, set by libavformat.
1403	*/
1404	int64_t duration;
1405
1406	/**
1407	* Total stream bitrate in bit/s, 0 if not
1408	* available. Never set it directly if the file_size and the
1409	* duration are known as FFmpeg can compute it automatically.
1410	*/
1411	int64_t bit_rate;
1412
1413	unsigned int packet_size;
1414	int max_delay;
1415
1416	/**
1417	* Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
1418	* Set by the user before avformat_open_input() / avformat_write_header().
1419	*/
1420	int flags;
1421	#define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
1422	#define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
1423	#define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
1424	#define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
1425	#define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container
1426	#define AVFMT_FLAG_NOPARSE 0x0020 ///< Do not use AVParsers, you also must set AVFMT_FLAG_NOFILLIN as the filling 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
1427	#define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
1428	#define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
1429	#define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
1430	#define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
1431	/**
1432	* When muxing, try to avoid writing any random/volatile data to the output.
1433	* This includes any random IDs, real-time timestamps/dates, muxer version, etc.
1434	*
1435	* This flag is mainly intended for testing.
1436	*/
1437	#define AVFMT_FLAG_BITEXACT 0x0400
1438	#define AVFMT_FLAG_SORT_DTS 0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
1439	#define AVFMT_FLAG_FAST_SEEK 0x80000 ///< Enable fast, but inaccurate seeks for some formats
1440	#define AVFMT_FLAG_AUTO_BSF 0x200000 ///< Add bitstream filters as requested by the muxer
1441
1442	/**
1443	* Maximum number of bytes read from input in order to determine stream
1444	* properties. Used when reading the global header and in
1445	* avformat_find_stream_info().
1446	*
1447	* Demuxing only, set by the caller before avformat_open_input().
1448	*
1449	* @note this is \e not used for determining the \ref AVInputFormat
1450	* "input format"
1451	* @see format_probesize
1452	*/
1453	int64_t probesize;
1454
1455	/**
1456	* Maximum duration (in AV_TIME_BASE units) of the data read
1457	* from input in avformat_find_stream_info().
1458	* Demuxing only, set by the caller before avformat_find_stream_info().
1459	* Can be set to 0 to let avformat choose using a heuristic.
1460	*/
1461	int64_t max_analyze_duration;
1462
1463	const uint8_t *key;
1464	int keylen;
1465
1466	unsigned int nb_programs;
1467	AVProgram **programs;
1468
1469	/**
1470	* Forced video codec_id.
1471	* Demuxing: Set by user.
1472	*/
1473	enum AVCodecID video_codec_id;
1474
1475	/**
1476	* Forced audio codec_id.
1477	* Demuxing: Set by user.
1478	*/
1479	enum AVCodecID audio_codec_id;
1480
1481	/**
1482	* Forced subtitle codec_id.
1483	* Demuxing: Set by user.
1484	*/
1485	enum AVCodecID subtitle_codec_id;
1486
1487	/**
1488	* Forced Data codec_id.
1489	* Demuxing: Set by user.
1490	*/
1491	enum AVCodecID data_codec_id;
1492
1493	/**
1494	* Metadata that applies to the whole file.
1495	*
1496	* - demuxing: set by libavformat in avformat_open_input()
1497	* - muxing: may be set by the caller before avformat_write_header()
1498	*
1499	* Freed by libavformat in avformat_free_context().
1500	*/
1501	AVDictionary *metadata;
1502
1503	/**
1504	* Start time of the stream in real world time, in microseconds
1505	* since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1506	* stream was captured at this real world time.
1507	* - muxing: Set by the caller before avformat_write_header(). If set to
1508	* either 0 or AV_NOPTS_VALUE, then the current wall-time will
1509	* be used.
1510	* - demuxing: Set by libavformat. AV_NOPTS_VALUE if unknown. Note that
1511	* the value may become known after some number of frames
1512	* have been received.
1513	*/
1514	int64_t start_time_realtime;
1515
1516	/**
1517	* The number of frames used for determining the framerate in
1518	* avformat_find_stream_info().
1519	* Demuxing only, set by the caller before avformat_find_stream_info().
1520	*/
1521	int fps_probe_size;
1522
1523	/**
1524	* Error recognition; higher values will detect more errors but may
1525	* misdetect some more or less valid parts as errors.
1526	* Demuxing only, set by the caller before avformat_open_input().
1527	*/
1528	int error_recognition;
1529
1530	/**
1531	* Custom interrupt callbacks for the I/O layer.
1532	*
1533	* demuxing: set by the user before avformat_open_input().
1534	* muxing: set by the user before avformat_write_header()
1535	* (mainly useful for AVFMT_NOFILE formats). The callback
1536	* should also be passed to avio_open2() if it's used to
1537	* open the file.
1538	*/
1539	AVIOInterruptCB interrupt_callback;
1540
1541	/**
1542	* Flags to enable debugging.
1543	*/
1544	int debug;
1545	#define FF_FDEBUG_TS 0x0001
1546
1547	/**
1548	* The maximum number of streams.
1549	* - encoding: unused
1550	* - decoding: set by user
1551	*/
1552	int max_streams;
1553
1554	/**
1555	* Maximum amount of memory in bytes to use for the index of each stream.
1556	* If the index exceeds this size, entries will be discarded as
1557	* needed to maintain a smaller size. This can lead to slower or less
1558	* accurate seeking (depends on demuxer).
1559	* Demuxers for which a full in-memory index is mandatory will ignore
1560	* this.
1561	* - muxing: unused
1562	* - demuxing: set by user
1563	*/
1564	unsigned int max_index_size;
1565
1566	/**
1567	* Maximum amount of memory in bytes to use for buffering frames
1568	* obtained from realtime capture devices.
1569	*/
1570	unsigned int max_picture_buffer;
1571
1572	/**
1573	* Maximum buffering duration for interleaving.
1574	*
1575	* To ensure all the streams are interleaved correctly,
1576	* av_interleaved_write_frame() will wait until it has at least one packet
1577	* for each stream before actually writing any packets to the output file.
1578	* When some streams are "sparse" (i.e. there are large gaps between
1579	* successive packets), this can result in excessive buffering.
1580	*
1581	* This field specifies the maximum difference between the timestamps of the
1582	* first and the last packet in the muxing queue, above which libavformat
1583	* will output a packet regardless of whether it has queued a packet for all
1584	* the streams.
1585	*
1586	* Muxing only, set by the caller before avformat_write_header().
1587	*/
1588	int64_t max_interleave_delta;
1589
1590	/**
1591	* Maximum number of packets to read while waiting for the first timestamp.
1592	* Decoding only.
1593	*/
1594	int max_ts_probe;
1595
1596	/**
1597	* Max chunk time in microseconds.
1598	* Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1599	* - encoding: Set by user
1600	* - decoding: unused
1601	*/
1602	int max_chunk_duration;
1603
1604	/**
1605	* Max chunk size in bytes
1606	* Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1607	* - encoding: Set by user
1608	* - decoding: unused
1609	*/
1610	int max_chunk_size;
1611
1612	/**
1613	* Maximum number of packets that can be probed
1614	* - encoding: unused
1615	* - decoding: set by user
1616	*/
1617	int max_probe_packets;
1618
1619	/**
1620	* Allow non-standard and experimental extension
1621	* @see AVCodecContext.strict_std_compliance
1622	*/
1623	int strict_std_compliance;
1624
1625	/**
1626	* Flags indicating events happening on the file, a combination of
1627	* AVFMT_EVENT_FLAG_*.
1628	*
1629	* - demuxing: may be set by the demuxer in avformat_open_input(),
1630	* avformat_find_stream_info() and av_read_frame(). Flags must be cleared
1631	* by the user once the event has been handled.
1632	* - muxing: may be set by the user after avformat_write_header() to
1633	* indicate a user-triggered event. The muxer will clear the flags for
1634	* events it has handled in av_[interleaved]_write_frame().
1635	*/
1636	int event_flags;
1637	/**
1638	* - demuxing: the demuxer read new metadata from the file and updated
1639	* AVFormatContext.metadata accordingly
1640	* - muxing: the user updated AVFormatContext.metadata and wishes the muxer to
1641	* write it into the file
1642	*/
1643	#define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001
1644
1645
1646	/**
1647	* Avoid negative timestamps during muxing.
1648	* Any value of the AVFMT_AVOID_NEG_TS_* constants.
1649	* Note, this works better when using av_interleaved_write_frame().
1650	* - muxing: Set by user
1651	* - demuxing: unused
1652	*/
1653	int avoid_negative_ts;
1654	#define AVFMT_AVOID_NEG_TS_AUTO -1 ///< Enabled when required by target format
1655	#define AVFMT_AVOID_NEG_TS_DISABLED 0 ///< Do not shift timestamps even when they are negative.
1656	#define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
1657	#define AVFMT_AVOID_NEG_TS_MAKE_ZERO 2 ///< Shift timestamps so that they start at 0
1658
1659	/**
1660	* Audio preload in microseconds.
1661	* Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1662	* - encoding: Set by user
1663	* - decoding: unused
1664	*/
1665	int audio_preload;
1666
1667	/**
1668	* forces the use of wallclock timestamps as pts/dts of packets
1669	* This has undefined results in the presence of B frames.
1670	* - encoding: unused
1671	* - decoding: Set by user
1672	*/
1673	int use_wallclock_as_timestamps;
1674
1675	/**
1676	* Skip duration calculation in estimate_timings_from_pts.
1677	* - encoding: unused
1678	* - decoding: set by user
1679	*
1680	* @see duration_probesize
1681	*/
1682	int skip_estimate_duration_from_pts;
1683
1684	/**
1685	* avio flags, used to force AVIO_FLAG_DIRECT.
1686	* - encoding: unused
1687	* - decoding: Set by user
1688	*/
1689	int avio_flags;
1690
1691	/**
1692	* The duration field can be estimated through various ways, and this field can be used
1693	* to know how the duration was estimated.
1694	* - encoding: unused
1695	* - decoding: Read by user
1696	*/
1697	enum AVDurationEstimationMethod duration_estimation_method;
1698
1699	/**
1700	* Skip initial bytes when opening stream
1701	* - encoding: unused
1702	* - decoding: Set by user
1703	*/
1704	int64_t skip_initial_bytes;
1705
1706	/**
1707	* Correct single timestamp overflows
1708	* - encoding: unused
1709	* - decoding: Set by user
1710	*/
1711	unsigned int correct_ts_overflow;
1712
1713	/**
1714	* Force seeking to any (also non key) frames.
1715	* - encoding: unused
1716	* - decoding: Set by user
1717	*/
1718	int seek2any;
1719
1720	/**
1721	* Flush the I/O context after each packet.
1722	* - encoding: Set by user
1723	* - decoding: unused
1724	*/
1725	int flush_packets;
1726
1727	/**
1728	* format probing score.
1729	* The maximal score is AVPROBE_SCORE_MAX, its set when the demuxer probes
1730	* the format.
1731	* - encoding: unused
1732	* - decoding: set by avformat, read by user
1733	*/
1734	int probe_score;
1735
1736	/**
1737	* Maximum number of bytes read from input in order to identify the
1738	* \ref AVInputFormat "input format". Only used when the format is not set
1739	* explicitly by the caller.
1740	*
1741	* Demuxing only, set by the caller before avformat_open_input().
1742	*
1743	* @see probesize
1744	*/
1745	int format_probesize;
1746
1747	/**
1748	* ',' separated list of allowed decoders.
1749	* If NULL then all are allowed
1750	* - encoding: unused
1751	* - decoding: set by user
1752	*/
1753	char *codec_whitelist;
1754
1755	/**
1756	* ',' separated list of allowed demuxers.
1757	* If NULL then all are allowed
1758	* - encoding: unused
1759	* - decoding: set by user
1760	*/
1761	char *format_whitelist;
1762
1763	/**
1764	* ',' separated list of allowed protocols.
1765	* - encoding: unused
1766	* - decoding: set by user
1767	*/
1768	char *protocol_whitelist;
1769
1770	/**
1771	* ',' separated list of disallowed protocols.
1772	* - encoding: unused
1773	* - decoding: set by user
1774	*/
1775	char *protocol_blacklist;
1776
1777	/**
1778	* IO repositioned flag.
1779	* This is set by avformat when the underlying IO context read pointer
1780	* is repositioned, for example when doing byte based seeking.
1781	* Demuxers can use the flag to detect such changes.
1782	*/
1783	int io_repositioned;
1784
1785	/**
1786	* Forced video codec.
1787	* This allows forcing a specific decoder, even when there are multiple with
1788	* the same codec_id.
1789	* Demuxing: Set by user
1790	*/
1791	const struct AVCodec *video_codec;
1792
1793	/**
1794	* Forced audio codec.
1795	* This allows forcing a specific decoder, even when there are multiple with
1796	* the same codec_id.
1797	* Demuxing: Set by user
1798	*/
1799	const struct AVCodec *audio_codec;
1800
1801	/**
1802	* Forced subtitle codec.
1803	* This allows forcing a specific decoder, even when there are multiple with
1804	* the same codec_id.
1805	* Demuxing: Set by user
1806	*/
1807	const struct AVCodec *subtitle_codec;
1808
1809	/**
1810	* Forced data codec.
1811	* This allows forcing a specific decoder, even when there are multiple with
1812	* the same codec_id.
1813	* Demuxing: Set by user
1814	*/
1815	const struct AVCodec *data_codec;
1816
1817	/**
1818	* Number of bytes to be written as padding in a metadata header.
1819	* Demuxing: Unused.
1820	* Muxing: Set by user.
1821	*/
1822	int metadata_header_padding;
1823
1824	/**
1825	* User data.
1826	* This is a place for some private data of the user.
1827	*/
1828	void *opaque;
1829
1830	/**
1831	* Callback used by devices to communicate with application.
1832	*/
1833	av_format_control_message control_message_cb;
1834
1835	/**
1836	* Output timestamp offset, in microseconds.
1837	* Muxing: set by user
1838	*/
1839	int64_t output_ts_offset;
1840
1841	/**
1842	* dump format separator.
1843	* can be ", " or "\n " or anything else
1844	* - muxing: Set by user.
1845	* - demuxing: Set by user.
1846	*/
1847	uint8_t *dump_separator;
1848
1849	/**
1850	* A callback for opening new IO streams.
1851	*
1852	* Whenever a muxer or a demuxer needs to open an IO stream (typically from
1853	* avformat_open_input() for demuxers, but for certain formats can happen at
1854	* other times as well), it will call this callback to obtain an IO context.
1855	*
1856	* @param s the format context
1857	* @param pb on success, the newly opened IO context should be returned here
1858	* @param url the url to open
1859	* @param flags a combination of AVIO_FLAG_*
1860	* @param options a dictionary of additional options, with the same
1861	* semantics as in avio_open2()
1862	* @return 0 on success, a negative AVERROR code on failure
1863	*
1864	* @note Certain muxers and demuxers do nesting, i.e. they open one or more
1865	* additional internal format contexts. Thus the AVFormatContext pointer
1866	* passed to this callback may be different from the one facing the caller.
1867	* It will, however, have the same 'opaque' field.
1868	*/
1869	int (io_open)(struct* AVFormatContext s, AVIOContext pb, const* char *url,
1870	int flags, AVDictionary **options);
1871
1872	/**
1873	* A callback for closing the streams opened with AVFormatContext.io_open().
1874	*
1875	* @param s the format context
1876	* @param pb IO context to be closed and freed
1877	* @return 0 on success, a negative AVERROR code on failure
1878	*/
1879	int (io_close2)(struct* AVFormatContext s, AVIOContext pb);
1880
1881	/**
1882	* Maximum number of bytes read from input in order to determine stream durations
1883	* when using estimate_timings_from_pts in avformat_find_stream_info().
1884	* Demuxing only, set by the caller before avformat_find_stream_info().
1885	* Can be set to 0 to let avformat choose using a heuristic.
1886	*
1887	* @see skip_estimate_duration_from_pts
1888	*/
1889	int64_t duration_probesize;
1890
1891	/**
1892	* Name of this format context, only used for logging purposes.
1893	*/
1894	char *name;
1895	} AVFormatContext;
1896
1897	/**
1898	* @defgroup lavf_core Core functions
1899	* @ingroup libavf
1900	*
1901	* Functions for querying libavformat capabilities, allocating core structures,
1902	* etc.
1903	* @{
1904	*/
1905
1906	/**
1907	* Return the LIBAVFORMAT_VERSION_INT constant.
1908	*/
1909	unsigned avformat_version(void);
1910
1911	/**
1912	* Return the libavformat build-time configuration.
1913	*/
1914	const char avformat_configuration(void*);
1915
1916	/**
1917	* Return the libavformat license.
1918	*/
1919	const char avformat_license(void*);
1920
1921	/**
1922	* Do global initialization of network libraries. This is optional,
1923	* and not recommended anymore.
1924	*
1925	* This functions only exists to work around thread-safety issues
1926	* with older GnuTLS or OpenSSL libraries. If libavformat is linked
1927	* to newer versions of those libraries, or if you do not use them,
1928	* calling this function is unnecessary. Otherwise, you need to call
1929	* this function before any other threads using them are started.
1930	*
1931	* This function will be deprecated once support for older GnuTLS and
1932	* OpenSSL libraries is removed, and this function has no purpose
1933	* anymore.
1934	*/
1935	int avformat_network_init(void);
1936
1937	/**
1938	* Undo the initialization done by avformat_network_init. Call it only
1939	* once for each time you called avformat_network_init.
1940	*/
1941	int avformat_network_deinit(void);
1942
1943	/**
1944	* Iterate over all registered muxers.
1945	*
1946	* @param opaque a pointer where libavformat will store the iteration state. Must
1947	* point to NULL to start the iteration.
1948	*
1949	* @return the next registered muxer or NULL when the iteration is
1950	* finished
1951	*/
1952	const AVOutputFormat av_muxer_iterate(void* **opaque);
1953
1954	/**
1955	* Iterate over all registered demuxers.
1956	*
1957	* @param opaque a pointer where libavformat will store the iteration state.
1958	* Must point to NULL to start the iteration.
1959	*
1960	* @return the next registered demuxer or NULL when the iteration is
1961	* finished
1962	*/
1963	const AVInputFormat av_demuxer_iterate(void* **opaque);
1964
1965	/**
1966	* Allocate an AVFormatContext.
1967	* avformat_free_context() can be used to free the context and everything
1968	* allocated by the framework within it.
1969	*/
1970	AVFormatContext avformat_alloc_context(void*);
1971
1972	/**
1973	* Free an AVFormatContext and all its streams.
1974	* @param s context to free
1975	*/
1976	void avformat_free_context(AVFormatContext *s);
1977
1978	/**
1979	* Get the AVClass for AVFormatContext. It can be used in combination with
1980	* AV_OPT_SEARCH_FAKE_OBJ for examining options.
1981	*
1982	* @see av_opt_find().
1983	*/
1984	const AVClass avformat_get_class(void*);
1985
1986	/**
1987	* Get the AVClass for AVStream. It can be used in combination with
1988	* AV_OPT_SEARCH_FAKE_OBJ for examining options.
1989	*
1990	* @see av_opt_find().
1991	*/
1992	const AVClass av_stream_get_class(void*);
1993
1994	/**
1995	* Get the AVClass for AVStreamGroup. It can be used in combination with
1996	* AV_OPT_SEARCH_FAKE_OBJ for examining options.
1997	*
1998	* @see av_opt_find().
1999	*/
2000	const AVClass av_stream_group_get_class(void*);
2001
2002	/**
2003	* @return a string identifying the stream group type, or NULL if unknown
2004	*/
2005	const char avformat_stream_group_name(enum* AVStreamGroupParamsType type);
2006
2007	/**
2008	* Add a new empty stream group to a media file.
2009	*
2010	* When demuxing, it may be called by the demuxer in read_header(). If the
2011	* flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
2012	* be called in read_packet().
2013	*
2014	* When muxing, may be called by the user before avformat_write_header().
2015	*
2016	* User is required to call avformat_free_context() to clean up the allocation
2017	* by avformat_stream_group_create().
2018	*
2019	* New streams can be added to the group with avformat_stream_group_add_stream().
2020	*
2021	* @param s media file handle
2022	*
2023	* @return newly created group or NULL on error.
2024	* @see avformat_new_stream, avformat_stream_group_add_stream.
2025	*/
2026	AVStreamGroup avformat_stream_group_create(AVFormatContext s,
2027	enum AVStreamGroupParamsType type,
2028	AVDictionary **options);
2029
2030	/**
2031	* Add a new stream to a media file.
2032	*
2033	* When demuxing, it is called by the demuxer in read_header(). If the
2034	* flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
2035	* be called in read_packet().
2036	*
2037	* When muxing, should be called by the user before avformat_write_header().
2038	*
2039	* User is required to call avformat_free_context() to clean up the allocation
2040	* by avformat_new_stream().
2041	*
2042	* @param s media file handle
2043	* @param c unused, does nothing
2044	*
2045	* @return newly created stream or NULL on error.
2046	*/
2047	AVStream avformat_new_stream(AVFormatContext s, const struct AVCodec *c);
2048
2049	/**
2050	* Add an already allocated stream to a stream group.
2051	*
2052	* When demuxing, it may be called by the demuxer in read_header(). If the
2053	* flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
2054	* be called in read_packet().
2055	*
2056	* When muxing, may be called by the user before avformat_write_header() after
2057	* having allocated a new group with avformat_stream_group_create() and stream with
2058	* avformat_new_stream().
2059	*
2060	* User is required to call avformat_free_context() to clean up the allocation
2061	* by avformat_stream_group_add_stream().
2062	*
2063	* @param stg stream group belonging to a media file.
2064	* @param st stream in the media file to add to the group.
2065	*
2066	* @retval 0 success
2067	* @retval AVERROR(EEXIST) the stream was already in the group
2068	* @retval "another negative error code" legitimate errors
2069	*
2070	* @see avformat_new_stream, avformat_stream_group_create.
2071	*/
2072	int avformat_stream_group_add_stream(AVStreamGroup stg, AVStream st);
2073
2074	AVProgram av_new_program(AVFormatContext s, int id);
2075
2076	/**
2077	* @}
2078	*/
2079
2080
2081	/**
2082	* Allocate an AVFormatContext for an output format.
2083	* avformat_free_context() can be used to free the context and
2084	* everything allocated by the framework within it.
2085	*
2086	* @param ctx pointee is set to the created format context,
2087	* or to NULL in case of failure
2088	* @param oformat format to use for allocating the context, if NULL
2089	* format_name and filename are used instead
2090	* @param format_name the name of output format to use for allocating the
2091	* context, if NULL filename is used instead
2092	* @param filename the name of the filename to use for allocating the
2093	* context, may be NULL
2094	*
2095	* @return >= 0 in case of success, a negative AVERROR code in case of
2096	* failure
2097	*/
2098	int avformat_alloc_output_context2(AVFormatContext *ctx, const* AVOutputFormat *oformat,
2099	const char format_name, const* char *filename);
2100
2101	/**
2102	* @addtogroup lavf_decoding
2103	* @{
2104	*/
2105
2106	/**
2107	* Find AVInputFormat based on the short name of the input format.
2108	*/
2109	const AVInputFormat av_find_input_format(const* char *short_name);
2110
2111	/**
2112	* Guess the file format.
2113	*
2114	* @param pd data to be probed
2115	* @param is_opened Whether the file is already opened; determines whether
2116	* demuxers with or without AVFMT_NOFILE are probed.
2117	*/
2118	const AVInputFormat av_probe_input_format(const* AVProbeData pd, int* is_opened);
2119
2120	/**
2121	* Guess the file format.
2122	*
2123	* @param pd data to be probed
2124	* @param is_opened Whether the file is already opened; determines whether
2125	* demuxers with or without AVFMT_NOFILE are probed.
2126	* @param score_max A probe score larger that this is required to accept a
2127	* detection, the variable is set to the actual detection
2128	* score afterwards.
2129	* If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
2130	* to retry with a larger probe buffer.
2131	*/
2132	const AVInputFormat av_probe_input_format2(const* AVProbeData *pd,
2133	int is_opened, int *score_max);
2134
2135	/**
2136	* Guess the file format.
2137	*
2138	* @param is_opened Whether the file is already opened; determines whether
2139	* demuxers with or without AVFMT_NOFILE are probed.
2140	* @param score_ret The score of the best detection.
2141	*/
2142	const AVInputFormat av_probe_input_format3(const* AVProbeData *pd,
2143	int is_opened, int *score_ret);
2144
2145	/**
2146	* Probe a bytestream to determine the input format. Each time a probe returns
2147	* with a score that is too low, the probe buffer size is increased and another
2148	* attempt is made. When the maximum probe size is reached, the input format
2149	* with the highest score is returned.
2150	*
2151	* @param pb the bytestream to probe
2152	* @param fmt the input format is put here
2153	* @param url the url of the stream
2154	* @param logctx the log context
2155	* @param offset the offset within the bytestream to probe from
2156	* @param max_probe_size the maximum probe buffer size (zero for default)
2157	*
2158	* @return the score in case of success, a negative value corresponding to an
2159	* the maximal score is AVPROBE_SCORE_MAX
2160	* AVERROR code otherwise
2161	*/
2162	int av_probe_input_buffer2(AVIOContext pb, const* AVInputFormat **fmt,
2163	const char url, void* *logctx,
2164	unsigned int offset, unsigned int max_probe_size);
2165
2166	/**
2167	* Like av_probe_input_buffer2() but returns 0 on success
2168	*/
2169	int av_probe_input_buffer(AVIOContext pb, const* AVInputFormat **fmt,
2170	const char url, void* *logctx,
2171	unsigned int offset, unsigned int max_probe_size);
2172
2173	/**
2174	* Open an input stream and read the header. The codecs are not opened.
2175	* The stream must be closed with avformat_close_input().
2176	*
2177	* @param ps Pointer to user-supplied AVFormatContext (allocated by
2178	* avformat_alloc_context). May be a pointer to NULL, in
2179	* which case an AVFormatContext is allocated by this
2180	* function and written into ps.
2181	* Note that a user-supplied AVFormatContext will be freed
2182	* on failure and its pointer set to NULL.
2183	* @param url URL of the stream to open.
2184	* @param fmt If non-NULL, this parameter forces a specific input format.
2185	* Otherwise the format is autodetected.
2186	* @param options A dictionary filled with AVFormatContext and demuxer-private
2187	* options.
2188	* On return this parameter will be destroyed and replaced with
2189	* a dict containing options that were not found. May be NULL.
2190	*
2191	* @return 0 on success; on failure: frees ps, sets its pointer to NULL,
2192	* and returns a negative AVERROR.
2193	*
2194	* @note If you want to use custom IO, preallocate the format context and set its pb field.
2195	*/
2196	int avformat_open_input(AVFormatContext *ps, const* char *url,
2197	const AVInputFormat fmt, AVDictionary *options);
2198
2199	/**
2200	* Read packets of a media file to get stream information. This
2201	* is useful for file formats with no headers such as MPEG. This
2202	* function also computes the real framerate in case of MPEG-2 repeat
2203	* frame mode.
2204	* The logical file position is not changed by this function;
2205	* examined packets may be buffered for later processing.
2206	*
2207	* @param ic media file handle
2208	* @param options If non-NULL, an ic.nb_streams long array of pointers to
2209	* dictionaries, where i-th member contains options for
2210	* codec corresponding to i-th stream.
2211	* On return each dictionary will be filled with options that were not found.
2212	* @return >=0 if OK, AVERROR_xxx on error
2213	*
2214	* @note this function isn't guaranteed to open all the codecs, so
2215	* options being non-empty at return is a perfectly normal behavior.
2216	*
2217	* @todo Let the user decide somehow what information is needed so that
2218	* we do not waste time getting stuff the user does not need.
2219	*/
2220	int avformat_find_stream_info(AVFormatContext ic, AVDictionary *options);
2221
2222	/**
2223	* Find the programs which belong to a given stream.
2224	*
2225	* @param ic media file handle
2226	* @param last the last found program, the search will start after this
2227	* program, or from the beginning if it is NULL
2228	* @param s stream index
2229	*
2230	* @return the next program which belongs to s, NULL if no program is found or
2231	* the last program is not among the programs of ic.
2232	*/
2233	AVProgram av_find_program_from_stream(AVFormatContext ic, AVProgram last, int* s);
2234
2235	void av_program_add_stream_index(AVFormatContext ac, int* progid, unsigned int idx);
2236
2237	/**
2238	* Find the "best" stream in the file.
2239	* The best stream is determined according to various heuristics as the most
2240	* likely to be what the user expects.
2241	* If the decoder parameter is non-NULL, av_find_best_stream will find the
2242	* default decoder for the stream's codec; streams for which no decoder can
2243	* be found are ignored.
2244	*
2245	* @param ic media file handle
2246	* @param type stream type: video, audio, subtitles, etc.
2247	* @param wanted_stream_nb user-requested stream number,
2248	* or -1 for automatic selection
2249	* @param related_stream try to find a stream related (eg. in the same
2250	* program) to this one, or -1 if none
2251	* @param decoder_ret if non-NULL, returns the decoder for the
2252	* selected stream
2253	* @param flags flags; none are currently defined
2254	*
2255	* @return the non-negative stream number in case of success,
2256	* AVERROR_STREAM_NOT_FOUND if no stream with the requested type
2257	* could be found,
2258	* AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
2259	*
2260	* @note If av_find_best_stream returns successfully and decoder_ret is not
2261	* NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
2262	*/
2263	int av_find_best_stream(AVFormatContext *ic,
2264	enum AVMediaType type,
2265	int wanted_stream_nb,
2266	int related_stream,
2267	const struct AVCodec **decoder_ret,
2268	int flags);
2269
2270	/**
2271	* Return the next frame of a stream.
2272	* This function returns what is stored in the file, and does not validate
2273	* that what is there are valid frames for the decoder. It will split what is
2274	* stored in the file into frames and return one for each call. It will not
2275	* omit invalid data between valid frames so as to give the decoder the maximum
2276	* information possible for decoding.
2277	*
2278	* On success, the returned packet is reference-counted (pkt->buf is set) and
2279	* valid indefinitely. The packet must be freed with av_packet_unref() when
2280	* it is no longer needed. For video, the packet contains exactly one frame.
2281	* For audio, it contains an integer number of frames if each frame has
2282	* a known fixed size (e.g. PCM or ADPCM data). If the audio frames have
2283	* a variable size (e.g. MPEG audio), then it contains one frame.
2284	*
2285	* pkt->pts, pkt->dts and pkt->duration are always set to correct
2286	* values in AVStream.time_base units (and guessed if the format cannot
2287	* provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
2288	* has B-frames, so it is better to rely on pkt->dts if you do not
2289	* decompress the payload.
2290	*
2291	* @return 0 if OK, < 0 on error or end of file. On error, pkt will be blank
2292	* (as if it came from av_packet_alloc()).
2293	*
2294	* @note pkt will be initialized, so it may be uninitialized, but it must not
2295	* contain data that needs to be freed.
2296	*/
2297	int av_read_frame(AVFormatContext s, AVPacket pkt);
2298
2299	/**
2300	* Seek to the keyframe at timestamp.
2301	* 'timestamp' in 'stream_index'.
2302	*
2303	* @param s media file handle
2304	* @param stream_index If stream_index is (-1), a default stream is selected,
2305	* and timestamp is automatically converted from
2306	* AV_TIME_BASE units to the stream specific time_base.
2307	* @param timestamp Timestamp in AVStream.time_base units or, if no stream
2308	* is specified, in AV_TIME_BASE units.
2309	* @param flags flags which select direction and seeking mode
2310	*
2311	* @return >= 0 on success
2312	*/
2313	int av_seek_frame(AVFormatContext s, int* stream_index, int64_t timestamp,
2314	int flags);
2315
2316	/**
2317	* Seek to timestamp ts.
2318	* Seeking will be done so that the point from which all active streams
2319	* can be presented successfully will be closest to ts and within min/max_ts.
2320	* Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
2321	*
2322	* If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
2323	* are the file position (this may not be supported by all demuxers).
2324	* If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
2325	* in the stream with stream_index (this may not be supported by all demuxers).
2326	* Otherwise all timestamps are in units of the stream selected by stream_index
2327	* or if stream_index is -1, in AV_TIME_BASE units.
2328	* If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
2329	* keyframes (this may not be supported by all demuxers).
2330	* If flags contain AVSEEK_FLAG_BACKWARD, it is ignored.
2331	*
2332	* @param s media file handle
2333	* @param stream_index index of the stream which is used as time base reference
2334	* @param min_ts smallest acceptable timestamp
2335	* @param ts target timestamp
2336	* @param max_ts largest acceptable timestamp
2337	* @param flags flags
2338	* @return >=0 on success, error code otherwise
2339	*
2340	* @note This is part of the new seek API which is still under construction.
2341	*/
2342	int avformat_seek_file(AVFormatContext s, int* stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
2343
2344	/**
2345	* Discard all internally buffered data. This can be useful when dealing with
2346	* discontinuities in the byte stream. Generally works only with formats that
2347	* can resync. This includes headerless formats like MPEG-TS/TS but should also
2348	* work with NUT, Ogg and in a limited way AVI for example.
2349	*
2350	* The set of streams, the detected duration, stream parameters and codecs do
2351	* not change when calling this function. If you want a complete reset, it's
2352	* better to open a new AVFormatContext.
2353	*
2354	* This does not flush the AVIOContext (s->pb). If necessary, call
2355	* avio_flush(s->pb) before calling this function.
2356	*
2357	* @param s media file handle
2358	* @return >=0 on success, error code otherwise
2359	*/
2360	int avformat_flush(AVFormatContext *s);
2361
2362	/**
2363	* Start playing a network-based stream (e.g. RTSP stream) at the
2364	* current position.
2365	*/
2366	int av_read_play(AVFormatContext *s);
2367
2368	/**
2369	* Pause a network-based stream (e.g. RTSP stream).
2370	*
2371	* Use av_read_play() to resume it.
2372	*/
2373	int av_read_pause(AVFormatContext *s);
2374
2375	/**
2376	* Command IDs that can be sent to the demuxer
2377	*
2378	* The following commands can be sent to a demuxer
2379	* using ::avformat_send_command.
2380	*/
2381	enum AVFormatCommandID {
2382	/**
2383	* Send a RTSP `SET_PARAMETER` request to the server
2384	*
2385	* Sends an SET_PARAMETER RTSP command to the server,
2386	* with a data payload of type ::AVRTSPCommandRequest,
2387	* ownership of it and its data remains with the caller.
2388	*
2389	* A reply retrieved is of type ::AVRTSPResponse and it
2390	* and its contents must be freed by the caller.
2391	*/
2392	AVFORMAT_COMMAND_RTSP_SET_PARAMETER,
2393	};
2394
2395	typedef struct AVRTSPCommandRequest {
2396	/**
2397	* Headers sent in the request to the server
2398	*/
2399	AVDictionary *headers;
2400
2401	/**
2402	* Body payload size
2403	*/
2404	size_t body_len;
2405
2406	/**
2407	* Body payload
2408	*/
2409	char *body;
2410	} AVRTSPCommandRequest;
2411
2412	typedef struct AVRTSPResponse {
2413	/**
2414	* Response status code from server
2415	*/
2416	int status_code;
2417
2418	/**
2419	* Reason phrase from the server, describing the
2420	* status in a human-readable way.
2421	*/
2422	char *reason;
2423
2424	/**
2425	* Body payload size
2426	*/
2427	size_t body_len;
2428
2429	/**
2430	* Body payload
2431	*/
2432	unsigned char *body;
2433	} AVRTSPResponse;
2434
2435	/**
2436	* Send a command to the demuxer
2437	*
2438	* Sends the specified command and (depending on the command)
2439	* optionally a command-specific payload to the demuxer to handle.
2440	*
2441	* @param s Format context, must be allocated with
2442	* ::avformat_alloc_context.
2443	* @param id Identifier of type ::AVFormatCommandID,
2444	* indicating the command to send.
2445	* @param data Command-specific data, allocated by the caller
2446	* and ownership remains with the caller.
2447	* For details what is expected here, consult the
2448	* documentation of the respective ::AVFormatCommandID.
2449	*/
2450	int avformat_send_command(AVFormatContext s, enum* AVFormatCommandID id, void *data);
2451
2452	/**
2453	* Receive a command reply from the demuxer
2454	*
2455	* Retrieves a reply for a previously sent command from the muxer.
2456	*
2457	* @param s Format context, must be allocated with
2458	* ::avformat_alloc_context.
2459	* @param id Identifier of type ::AVFormatCommandID,
2460	* indicating the command for which to retrieve
2461	* the reply.
2462	* @param data_out Pointee is set to the command reply, the actual
2463	* type depends on the command. This is allocated by
2464	* the muxer and must be freed with ::av_free.
2465	* For details on the actual data set here, consult the
2466	* documentation of the respective ::AVFormatCommandID.
2467	*/
2468	int avformat_receive_command_reply(AVFormatContext s, enum* AVFormatCommandID id, void **data_out);
2469
2470	/**
2471	* Close an opened input AVFormatContext. Free it and all its contents
2472	* and set *s to NULL.
2473	*/
2474	void avformat_close_input(AVFormatContext **s);
2475	/**
2476	* @}
2477	*/
2478
2479	#define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
2480	#define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
2481	#define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
2482	#define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
2483
2484	/**
2485	* @addtogroup lavf_encoding
2486	* @{
2487	*/
2488
2489	#define AVSTREAM_INIT_IN_WRITE_HEADER 0 ///< stream parameters initialized in avformat_write_header
2490	#define AVSTREAM_INIT_IN_INIT_OUTPUT 1 ///< stream parameters initialized in avformat_init_output
2491
2492	/**
2493	* Allocate the stream private data and write the stream header to
2494	* an output media file.
2495	*
2496	* @param s Media file handle, must be allocated with
2497	* avformat_alloc_context().
2498	* Its \ref AVFormatContext.oformat "oformat" field must be set
2499	* to the desired output format;
2500	* Its \ref AVFormatContext.pb "pb" field must be set to an
2501	* already opened ::AVIOContext.
2502	* @param options An ::AVDictionary filled with AVFormatContext and
2503	* muxer-private options.
2504	* On return this parameter will be destroyed and replaced with
2505	* a dict containing options that were not found. May be NULL.
2506	*
2507	* @retval AVSTREAM_INIT_IN_WRITE_HEADER On success, if the codec had not already been
2508	* fully initialized in avformat_init_output().
2509	* @retval AVSTREAM_INIT_IN_INIT_OUTPUT On success, if the codec had already been fully
2510	* initialized in avformat_init_output().
2511	* @retval AVERROR A negative AVERROR on failure.
2512	*
2513	* @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_init_output.
2514	*/
2515	av_warn_unused_result
2516	int avformat_write_header(AVFormatContext s, AVDictionary *options);
2517
2518	/**
2519	* Allocate the stream private data and initialize the codec, but do not write the header.
2520	* May optionally be used before avformat_write_header() to initialize stream parameters
2521	* before actually writing the header.
2522	* If using this function, do not pass the same options to avformat_write_header().
2523	*
2524	* @param s Media file handle, must be allocated with
2525	* avformat_alloc_context().
2526	* Its \ref AVFormatContext.oformat "oformat" field must be set
2527	* to the desired output format;
2528	* Its \ref AVFormatContext.pb "pb" field must be set to an
2529	* already opened ::AVIOContext.
2530	* @param options An ::AVDictionary filled with AVFormatContext and
2531	* muxer-private options.
2532	* On return this parameter will be destroyed and replaced with
2533	* a dict containing options that were not found. May be NULL.
2534	*
2535	* @retval AVSTREAM_INIT_IN_WRITE_HEADER On success, if the codec requires
2536	* avformat_write_header to fully initialize.
2537	* @retval AVSTREAM_INIT_IN_INIT_OUTPUT On success, if the codec has been fully
2538	* initialized.
2539	* @retval AVERROR Anegative AVERROR on failure.
2540	*
2541	* @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_write_header.
2542	*/
2543	av_warn_unused_result
2544	int avformat_init_output(AVFormatContext s, AVDictionary *options);
2545
2546	/**
2547	* Write a packet to an output media file.
2548	*
2549	* This function passes the packet directly to the muxer, without any buffering
2550	* or reordering. The caller is responsible for correctly interleaving the
2551	* packets if the format requires it. Callers that want libavformat to handle
2552	* the interleaving should call av_interleaved_write_frame() instead of this
2553	* function.
2554	*
2555	* @param s media file handle
2556	* @param pkt The packet containing the data to be written. Note that unlike
2557	* av_interleaved_write_frame(), this function does not take
2558	* ownership of the packet passed to it (though some muxers may make
2559	* an internal reference to the input packet).
2560	* <br>
2561	* This parameter can be NULL (at any time, not just at the end), in
2562	* order to immediately flush data buffered within the muxer, for
2563	* muxers that buffer up data internally before writing it to the
2564	* output.
2565	* <br>
2566	* Packet's @ref AVPacket.stream_index "stream_index" field must be
2567	* set to the index of the corresponding stream in @ref
2568	* AVFormatContext.streams "s->streams".
2569	* <br>
2570	* The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2571	* must be set to correct values in the stream's timebase (unless the
2572	* output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2573	* they can be set to AV_NOPTS_VALUE).
2574	* The dts for subsequent packets passed to this function must be strictly
2575	* increasing when compared in their respective timebases (unless the
2576	* output format is flagged with the AVFMT_TS_NONSTRICT, then they
2577	* merely have to be nondecreasing). @ref AVPacket.duration
2578	* "duration") should also be set if known.
2579	* @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
2580	*
2581	* @see av_interleaved_write_frame()
2582	*/
2583	int av_write_frame(AVFormatContext s, AVPacket pkt);
2584
2585	/**
2586	* Write a packet to an output media file ensuring correct interleaving.
2587	*
2588	* This function will buffer the packets internally as needed to make sure the
2589	* packets in the output file are properly interleaved, usually ordered by
2590	* increasing dts. Callers doing their own interleaving should call
2591	* av_write_frame() instead of this function.
2592	*
2593	* Using this function instead of av_write_frame() can give muxers advance
2594	* knowledge of future packets, improving e.g. the behaviour of the mp4
2595	* muxer for VFR content in fragmenting mode.
2596	*
2597	* @param s media file handle
2598	* @param pkt The packet containing the data to be written.
2599	* <br>
2600	* If the packet is reference-counted, this function will take
2601	* ownership of this reference and unreference it later when it sees
2602	* fit. If the packet is not reference-counted, libavformat will
2603	* make a copy.
2604	* The returned packet will be blank (as if returned from
2605	* av_packet_alloc()), even on error.
2606	* <br>
2607	* This parameter can be NULL (at any time, not just at the end), to
2608	* flush the interleaving queues.
2609	* <br>
2610	* Packet's @ref AVPacket.stream_index "stream_index" field must be
2611	* set to the index of the corresponding stream in @ref
2612	* AVFormatContext.streams "s->streams".
2613	* <br>
2614	* The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2615	* must be set to correct values in the stream's timebase (unless the
2616	* output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2617	* they can be set to AV_NOPTS_VALUE).
2618	* The dts for subsequent packets in one stream must be strictly
2619	* increasing (unless the output format is flagged with the
2620	* AVFMT_TS_NONSTRICT, then they merely have to be nondecreasing).
2621	* @ref AVPacket.duration "duration" should also be set if known.
2622	*
2623	* @return 0 on success, a negative AVERROR on error.
2624	*
2625	* @see av_write_frame(), AVFormatContext.max_interleave_delta
2626	*/
2627	int av_interleaved_write_frame(AVFormatContext s, AVPacket pkt);
2628
2629	/**
2630	* Write an uncoded frame to an output media file.
2631	*
2632	* The frame must be correctly interleaved according to the container
2633	* specification; if not, av_interleaved_write_uncoded_frame() must be used.
2634	*
2635	* See av_interleaved_write_uncoded_frame() for details.
2636	*/
2637	int av_write_uncoded_frame(AVFormatContext s, int* stream_index,
2638	struct AVFrame *frame);
2639
2640	/**
2641	* Write an uncoded frame to an output media file.
2642	*
2643	* If the muxer supports it, this function makes it possible to write an AVFrame
2644	* structure directly, without encoding it into a packet.
2645	* It is mostly useful for devices and similar special muxers that use raw
2646	* video or PCM data and will not serialize it into a byte stream.
2647	*
2648	* To test whether it is possible to use it with a given muxer and stream,
2649	* use av_write_uncoded_frame_query().
2650	*
2651	* The caller gives up ownership of the frame and must not access it
2652	* afterwards.
2653	*
2654	* @return >=0 for success, a negative code on error
2655	*/
2656	int av_interleaved_write_uncoded_frame(AVFormatContext s, int* stream_index,
2657	struct AVFrame *frame);
2658
2659	/**
2660	* Test whether a muxer supports uncoded frame.
2661	*
2662	* @return >=0 if an uncoded frame can be written to that muxer and stream,
2663	* <0 if not
2664	*/
2665	int av_write_uncoded_frame_query(AVFormatContext s, int* stream_index);
2666
2667	/**
2668	* Write the stream trailer to an output media file and free the
2669	* file private data.
2670	*
2671	* May only be called after a successful call to avformat_write_header.
2672	*
2673	* @param s media file handle
2674	* @return 0 if OK, AVERROR_xxx on error
2675	*/
2676	int av_write_trailer(AVFormatContext *s);
2677
2678	/**
2679	* Return the output format in the list of registered output formats
2680	* which best matches the provided parameters, or return NULL if
2681	* there is no match.
2682	*
2683	* @param short_name if non-NULL checks if short_name matches with the
2684	* names of the registered formats
2685	* @param filename if non-NULL checks if filename terminates with the
2686	* extensions of the registered formats
2687	* @param mime_type if non-NULL checks if mime_type matches with the
2688	* MIME type of the registered formats
2689	*/
2690	const AVOutputFormat av_guess_format(const* char *short_name,
2691	const char *filename,
2692	const char *mime_type);
2693
2694	/**
2695	* Guess the codec ID based upon muxer and filename.
2696	*/
2697	enum AVCodecID av_guess_codec(const AVOutputFormat fmt, const* char *short_name,
2698	const char filename, const* char *mime_type,
2699	enum AVMediaType type);
2700
2701	/**
2702	* Get timing information for the data currently output.
2703	* The exact meaning of "currently output" depends on the format.
2704	* It is mostly relevant for devices that have an internal buffer and/or
2705	* work in real time.
2706	* @param s media file handle
2707	* @param stream stream in the media file
2708	* @param[out] dts DTS of the last packet output for the stream, in stream
2709	* time_base units
2710	* @param[out] wall absolute time when that packet whas output,
2711	* in microsecond
2712	* @retval 0 Success
2713	* @retval AVERROR(ENOSYS) The format does not support it
2714	*
2715	* @note Some formats or devices may not allow to measure dts and wall
2716	* atomically.
2717	*/
2718	int av_get_output_timestamp(struct AVFormatContext s, int* stream,
2719	int64_t dts, int64_t wall);
2720
2721
2722	/**
2723	* @}
2724	*/
2725
2726
2727	/**
2728	* @defgroup lavf_misc Utility functions
2729	* @ingroup libavf
2730	* @{
2731	*
2732	* Miscellaneous utility functions related to both muxing and demuxing
2733	* (or neither).
2734	*/
2735
2736	/**
2737	* Send a nice hexadecimal dump of a buffer to the specified file stream.
2738	*
2739	* @param f The file stream pointer where the dump should be sent to.
2740	* @param buf buffer
2741	* @param size buffer size
2742	*
2743	* @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
2744	*/
2745	void av_hex_dump(FILE f, const* uint8_t buf, int* size);
2746
2747	/**
2748	* Send a nice hexadecimal dump of a buffer to the log.
2749	*
2750	* @param avcl A pointer to an arbitrary struct of which the first field is a
2751	* pointer to an AVClass struct.
2752	* @param level The importance level of the message, lower values signifying
2753	* higher importance.
2754	* @param buf buffer
2755	* @param size buffer size
2756	*
2757	* @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
2758	*/
2759	void av_hex_dump_log(void avcl, int* level, const uint8_t buf, int* size);
2760
2761	/**
2762	* Send a nice dump of a packet to the specified file stream.
2763	*
2764	* @param f The file stream pointer where the dump should be sent to.
2765	* @param pkt packet to dump
2766	* @param dump_payload True if the payload must be displayed, too.
2767	* @param st AVStream that the packet belongs to
2768	*/
2769	void av_pkt_dump2(FILE f, const* AVPacket pkt, int* dump_payload, const AVStream *st);
2770
2771
2772	/**
2773	* Send a nice dump of a packet to the log.
2774	*
2775	* @param avcl A pointer to an arbitrary struct of which the first field is a
2776	* pointer to an AVClass struct.
2777	* @param level The importance level of the message, lower values signifying
2778	* higher importance.
2779	* @param pkt packet to dump
2780	* @param dump_payload True if the payload must be displayed, too.
2781	* @param st AVStream that the packet belongs to
2782	*/
2783	void av_pkt_dump_log2(void avcl, int* level, const AVPacket pkt, int* dump_payload,
2784	const AVStream *st);
2785
2786	/**
2787	* Get the AVCodecID for the given codec tag tag.
2788	* If no codec id is found returns AV_CODEC_ID_NONE.
2789	*
2790	* @param tags list of supported codec_id-codec_tag pairs, as stored
2791	* in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2792	* @param tag codec tag to match to a codec ID
2793	*/
2794	enum AVCodecID av_codec_get_id(const struct AVCodecTag * const tags, unsigned* int tag);
2795
2796	/**
2797	* Get the codec tag for the given codec id id.
2798	* If no codec tag is found returns 0.
2799	*
2800	* @param tags list of supported codec_id-codec_tag pairs, as stored
2801	* in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2802	* @param id codec ID to match to a codec tag
2803	*/
2804	unsigned int av_codec_get_tag(const struct AVCodecTag * const tags, enum* AVCodecID id);
2805
2806	/**
2807	* Get the codec tag for the given codec id.
2808	*
2809	* @param tags list of supported codec_id - codec_tag pairs, as stored
2810	* in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2811	* @param id codec id that should be searched for in the list
2812	* @param tag A pointer to the found tag
2813	* @return 0 if id was not found in tags, > 0 if it was found
2814	*/
2815	int av_codec_get_tag2(const struct AVCodecTag * const tags, enum* AVCodecID id,
2816	unsigned int *tag);
2817
2818	int av_find_default_stream_index(AVFormatContext *s);
2819
2820	/**
2821	* Get the index for a specific timestamp.
2822	*
2823	* @param st stream that the timestamp belongs to
2824	* @param timestamp timestamp to retrieve the index for
2825	* @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
2826	* to the timestamp which is <= the requested one, if backward
2827	* is 0, then it will be >=
2828	* if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
2829	* @return < 0 if no such timestamp could be found
2830	*/
2831	int av_index_search_timestamp(AVStream st, int64_t timestamp, int* flags);
2832
2833	/**
2834	* Get the index entry count for the given AVStream.
2835	*
2836	* @param st stream
2837	* @return the number of index entries in the stream
2838	*/
2839	int avformat_index_get_entries_count(const AVStream *st);
2840
2841	/**
2842	* Get the AVIndexEntry corresponding to the given index.
2843	*
2844	* @param st Stream containing the requested AVIndexEntry.
2845	* @param idx The desired index.
2846	* @return A pointer to the requested AVIndexEntry if it exists, NULL otherwise.
2847	*
2848	* @note The pointer returned by this function is only guaranteed to be valid
2849	* until any function that takes the stream or the parent AVFormatContext
2850	* as input argument is called.
2851	*/
2852	const AVIndexEntry avformat_index_get_entry(AVStream st, int idx);
2853
2854	/**
2855	* Get the AVIndexEntry corresponding to the given timestamp.
2856	*
2857	* @param st Stream containing the requested AVIndexEntry.
2858	* @param wanted_timestamp Timestamp to retrieve the index entry for.
2859	* @param flags If AVSEEK_FLAG_BACKWARD then the returned entry will correspond
2860	* to the timestamp which is <= the requested one, if backward
2861	* is 0, then it will be >=
2862	* if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise.
2863	* @return A pointer to the requested AVIndexEntry if it exists, NULL otherwise.
2864	*
2865	* @note The pointer returned by this function is only guaranteed to be valid
2866	* until any function that takes the stream or the parent AVFormatContext
2867	* as input argument is called.
2868	*/
2869	const AVIndexEntry avformat_index_get_entry_from_timestamp(AVStream st,
2870	int64_t wanted_timestamp,
2871	int flags);
2872	/**
2873	* Add an index entry into a sorted list. Update the entry if the list
2874	* already contains it.
2875	*
2876	* @param timestamp timestamp in the time base of the given stream
2877	*/
2878	int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
2879	int size, int distance, int flags);
2880
2881
2882	/**
2883	* Split a URL string into components.
2884	*
2885	* The pointers to buffers for storing individual components may be null,
2886	* in order to ignore that component. Buffers for components not found are
2887	* set to empty strings. If the port is not found, it is set to a negative
2888	* value.
2889	*
2890	* @param proto the buffer for the protocol
2891	* @param proto_size the size of the proto buffer
2892	* @param authorization the buffer for the authorization
2893	* @param authorization_size the size of the authorization buffer
2894	* @param hostname the buffer for the host name
2895	* @param hostname_size the size of the hostname buffer
2896	* @param port_ptr a pointer to store the port number in
2897	* @param path the buffer for the path
2898	* @param path_size the size of the path buffer
2899	* @param url the URL to split
2900	*/
2901	void av_url_split(char proto, int* proto_size,
2902	char authorization, int* authorization_size,
2903	char hostname, int* hostname_size,
2904	int *port_ptr,
2905	char path, int* path_size,
2906	const char *url);
2907
2908
2909	/**
2910	* Print detailed information about the input or output format, such as
2911	* duration, bitrate, streams, container, programs, metadata, side data,
2912	* codec and time base.
2913	*
2914	* @param ic the context to analyze
2915	* @param index index of the stream to dump information about
2916	* @param url the URL to print, such as source or destination file
2917	* @param is_output Select whether the specified context is an input(0) or output(1)
2918	*/
2919	void av_dump_format(AVFormatContext *ic,
2920	int index,
2921	const char *url,
2922	int is_output);
2923
2924
2925	#define AV_FRAME_FILENAME_FLAGS_MULTIPLE 1 ///< Allow multiple %d
2926	#define AV_FRAME_FILENAME_FLAGS_IGNORE_TRUNCATION 2 ///< Ignore truncated output instead of returning an error
2927
2928	/**
2929	* Return in 'buf' the path with '%d' replaced by a number.
2930	*
2931	* Also handles the '%0nd' format where 'n' is the total number
2932	* of digits and '%%'.
2933	*
2934	* @param buf destination buffer
2935	* @param buf_size destination buffer size
2936	* @param path numbered sequence string
2937	* @param number frame number
2938	* @param flags AV_FRAME_FILENAME_FLAGS_*
2939	* @return 0 if OK, -1 on format error
2940	*/
2941	int av_get_frame_filename2(char buf, int* buf_size,
2942	const char path, int* number, int flags);
2943
2944	int av_get_frame_filename(char buf, int* buf_size,
2945	const char path, int* number);
2946
2947	/**
2948	* Check whether filename actually is a numbered sequence generator.
2949	*
2950	* @param filename possible numbered sequence string
2951	* @return 1 if a valid numbered sequence string, 0 otherwise
2952	*/
2953	int av_filename_number_test(const char *filename);
2954
2955	/**
2956	* Generate an SDP for an RTP session.
2957	*
2958	* Note, this overwrites the id values of AVStreams in the muxer contexts
2959	* for getting unique dynamic payload types.
2960	*
2961	* @param ac array of AVFormatContexts describing the RTP streams. If the
2962	* array is composed by only one context, such context can contain
2963	* multiple AVStreams (one AVStream per RTP stream). Otherwise,
2964	* all the contexts in the array (an AVCodecContext per RTP stream)
2965	* must contain only one AVStream.
2966	* @param n_files number of AVCodecContexts contained in ac
2967	* @param buf buffer where the SDP will be stored (must be allocated by
2968	* the caller)
2969	* @param size the size of the buffer
2970	* @return 0 if OK, AVERROR_xxx on error
2971	*/
2972	int av_sdp_create(AVFormatContext ac[], int* n_files, char buf, int* size);
2973
2974	/**
2975	* Return a positive value if the given filename has one of the given
2976	* extensions, 0 otherwise.
2977	*
2978	* @param filename file name to check against the given extensions
2979	* @param extensions a comma-separated list of filename extensions
2980	*/
2981	int av_match_ext(const char filename, const* char *extensions);
2982
2983	/**
2984	* Test if the given container can store a codec.
2985	*
2986	* @param ofmt container to check for compatibility
2987	* @param codec_id codec to potentially store in container
2988	* @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
2989	*
2990	* @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
2991	* A negative number if this information is not available.
2992	*/
2993	int avformat_query_codec(const AVOutputFormat ofmt, enum* AVCodecID codec_id,
2994	int std_compliance);
2995
2996	struct AVBPrint;
2997	/**
2998	* Make a RFC 4281/6381 like string describing a codec for MIME types.
2999	*
3000	* @param par pointer to an AVCodecParameters struct describing the codec
3001	* @param frame_rate an AVRational for the frame rate, for deciding the
3002	* right profile for video codecs. Pass an invalid
3003	* AVRational (1/0) to indicate that it is unknown.
3004	* @param out the AVBPrint to write the output to
3005	* @return <0 on error
3006	*/
3007	int av_mime_codec_str(const AVCodecParameters *par,
3008	AVRational frame_rate, struct AVBPrint *out);
3009
3010	/**
3011	* @defgroup riff_fourcc RIFF FourCCs
3012	* @{
3013	* Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
3014	* meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
3015	* following code:
3016	* @code
3017	* uint32_t tag = MKTAG('H', '2', '6', '4');
3018	* const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
3019	* enum AVCodecID id = av_codec_get_id(table, tag);
3020	* @endcode
3021	*/
3022	/**
3023	* @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
3024	*/
3025	const struct AVCodecTag avformat_get_riff_video_tags(void*);
3026	/**
3027	* @return the table mapping RIFF FourCCs for audio to AVCodecID.
3028	*/
3029	const struct AVCodecTag avformat_get_riff_audio_tags(void*);
3030	/**
3031	* @return the table mapping MOV FourCCs for video to libavcodec AVCodecID.
3032	*/
3033	const struct AVCodecTag avformat_get_mov_video_tags(void*);
3034	/**
3035	* @return the table mapping MOV FourCCs for audio to AVCodecID.
3036	*/
3037	const struct AVCodecTag avformat_get_mov_audio_tags(void*);
3038
3039	/**
3040	* @}
3041	*/
3042
3043	/**
3044	* Guess the sample aspect ratio of a frame, based on both the stream and the
3045	* frame aspect ratio.
3046	*
3047	* Since the frame aspect ratio is set by the codec but the stream aspect ratio
3048	* is set by the demuxer, these two may not be equal. This function tries to
3049	* return the value that you should use if you would like to display the frame.
3050	*
3051	* Basic logic is to use the stream aspect ratio if it is set to something sane
3052	* otherwise use the frame aspect ratio. This way a container setting, which is
3053	* usually easy to modify can override the coded value in the frames.
3054	*
3055	* @param format the format context which the stream is part of
3056	* @param stream the stream which the frame is part of
3057	* @param frame the frame with the aspect ratio to be determined
3058	* @return the guessed (valid) sample_aspect_ratio, 0/1 if no idea
3059	*/
3060	AVRational av_guess_sample_aspect_ratio(AVFormatContext format, AVStream stream,
3061	struct AVFrame *frame);
3062
3063	/**
3064	* Guess the frame rate, based on both the container and codec information.
3065	*
3066	* @param ctx the format context which the stream is part of
3067	* @param stream the stream which the frame is part of
3068	* @param frame the frame for which the frame rate should be determined, may be NULL
3069	* @return the guessed (valid) frame rate, 0/1 if no idea
3070	*/
3071	AVRational av_guess_frame_rate(AVFormatContext ctx, AVStream stream,
3072	struct AVFrame *frame);
3073
3074	/**
3075	* Check if the stream st contained in s is matched by the stream specifier
3076	* spec.
3077	*
3078	* See the "stream specifiers" chapter in the documentation for the syntax
3079	* of spec.
3080	*
3081	* @return >0 if st is matched by spec;
3082	* 0 if st is not matched by spec;
3083	* AVERROR code if spec is invalid
3084	*
3085	* @note A stream specifier can match several streams in the format.
3086	*/
3087	int avformat_match_stream_specifier(AVFormatContext s, AVStream st,
3088	const char *spec);
3089
3090	int avformat_queue_attached_pictures(AVFormatContext *s);
3091
3092	#if FF_API_INTERNAL_TIMING
3093	enum AVTimebaseSource {
3094	AVFMT_TBCF_AUTO = -`1`,
3095	AVFMT_TBCF_DECODER,
3096	AVFMT_TBCF_DEMUXER,
3097	#if FF_API_R_FRAME_RATE
3098	AVFMT_TBCF_R_FRAMERATE,
3099	#endif
3100	};
3101
3102	/**
3103	* @deprecated do not call this function
3104	*/
3105	attribute_deprecated
3106	int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
3107	AVStream ost, const* AVStream *ist,
3108	enum AVTimebaseSource copy_tb);
3109
3110	/**
3111	* @deprecated do not call this function
3112	*/
3113	attribute_deprecated
3114	AVRational av_stream_get_codec_timebase(const AVStream *st);
3115	#endif
3116
3117
3118	/**
3119	* @}
3120	*/
3121
3122	#endif /* AVFORMAT_AVFORMAT_H */
3123

Browse the source code of include/libavformat/avformat.h