FFmpeg
avformat.h
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1 /*
2  * copyright (c) 2001 Fabrice Bellard
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVFORMAT_AVFORMAT_H
22 #define AVFORMAT_AVFORMAT_H
23 
24 /**
25  * @file
26  * @ingroup libavf
27  * Main libavformat public API header
28  */
29 
30 /**
31  * @defgroup libavf libavformat
32  * I/O and Muxing/Demuxing Library
33  *
34  * Libavformat (lavf) is a library for dealing with various media container
35  * formats. Its main two purposes are demuxing - i.e. splitting a media file
36  * into component streams, and the reverse process of muxing - writing supplied
37  * data in a specified container format. It also has an @ref lavf_io
38  * "I/O module" which supports a number of protocols for accessing the data (e.g.
39  * file, tcp, http and others).
40  * Unless you are absolutely sure you won't use libavformat's network
41  * capabilities, you should also call avformat_network_init().
42  *
43  * A supported input format is described by an AVInputFormat struct, conversely
44  * an output format is described by AVOutputFormat. You can iterate over all
45  * input/output formats using the av_demuxer_iterate / av_muxer_iterate() functions.
46  * The protocols layer is not part of the public API, so you can only get the names
47  * of supported protocols with the avio_enum_protocols() function.
48  *
49  * Main lavf structure used for both muxing and demuxing is AVFormatContext,
50  * which exports all information about the file being read or written. As with
51  * most Libavformat structures, its size is not part of public ABI, so it cannot be
52  * allocated on stack or directly with av_malloc(). To create an
53  * AVFormatContext, use avformat_alloc_context() (some functions, like
54  * avformat_open_input() might do that for you).
55  *
56  * Most importantly an AVFormatContext contains:
57  * @li the @ref AVFormatContext.iformat "input" or @ref AVFormatContext.oformat
58  * "output" format. It is either autodetected or set by user for input;
59  * always set by user for output.
60  * @li an @ref AVFormatContext.streams "array" of AVStreams, which describe all
61  * elementary streams stored in the file. AVStreams are typically referred to
62  * using their index in this array.
63  * @li an @ref AVFormatContext.pb "I/O context". It is either opened by lavf or
64  * set by user for input, always set by user for output (unless you are dealing
65  * with an AVFMT_NOFILE format).
66  *
67  * @section lavf_options Passing options to (de)muxers
68  * It is possible to configure lavf muxers and demuxers using the @ref avoptions
69  * mechanism. Generic (format-independent) libavformat options are provided by
70  * AVFormatContext, they can be examined from a user program by calling
71  * av_opt_next() / av_opt_find() on an allocated AVFormatContext (or its AVClass
72  * from avformat_get_class()). Private (format-specific) options are provided by
73  * AVFormatContext.priv_data if and only if AVInputFormat.priv_class /
74  * AVOutputFormat.priv_class of the corresponding format struct is non-NULL.
75  * Further options may be provided by the @ref AVFormatContext.pb "I/O context",
76  * if its AVClass is non-NULL, and the protocols layer. See the discussion on
77  * nesting in @ref avoptions documentation to learn how to access those.
78  *
79  * @section urls
80  * URL strings in libavformat are made of a scheme/protocol, a ':', and a
81  * scheme specific string. URLs without a scheme and ':' used for local files
82  * are supported but deprecated. "file:" should be used for local files.
83  *
84  * It is important that the scheme string is not taken from untrusted
85  * sources without checks.
86  *
87  * Note that some schemes/protocols are quite powerful, allowing access to
88  * both local and remote files, parts of them, concatenations of them, local
89  * audio and video devices and so on.
90  *
91  * @{
92  *
93  * @defgroup lavf_decoding Demuxing
94  * @{
95  * Demuxers read a media file and split it into chunks of data (@em packets). A
96  * @ref AVPacket "packet" contains one or more encoded frames which belongs to a
97  * single elementary stream. In the lavf API this process is represented by the
98  * avformat_open_input() function for opening a file, av_read_frame() for
99  * reading a single packet and finally avformat_close_input(), which does the
100  * cleanup.
101  *
102  * @section lavf_decoding_open Opening a media file
103  * The minimum information required to open a file is its URL, which
104  * is passed to avformat_open_input(), as in the following code:
105  * @code
106  * const char *url = "file:in.mp3";
107  * AVFormatContext *s = NULL;
108  * int ret = avformat_open_input(&s, url, NULL, NULL);
109  * if (ret < 0)
110  * abort();
111  * @endcode
112  * The above code attempts to allocate an AVFormatContext, open the
113  * specified file (autodetecting the format) and read the header, exporting the
114  * information stored there into s. Some formats do not have a header or do not
115  * store enough information there, so it is recommended that you call the
116  * avformat_find_stream_info() function which tries to read and decode a few
117  * frames to find missing information.
118  *
119  * In some cases you might want to preallocate an AVFormatContext yourself with
120  * avformat_alloc_context() and do some tweaking on it before passing it to
121  * avformat_open_input(). One such case is when you want to use custom functions
122  * for reading input data instead of lavf internal I/O layer.
123  * To do that, create your own AVIOContext with avio_alloc_context(), passing
124  * your reading callbacks to it. Then set the @em pb field of your
125  * AVFormatContext to newly created AVIOContext.
126  *
127  * Since the format of the opened file is in general not known until after
128  * avformat_open_input() has returned, it is not possible to set demuxer private
129  * options on a preallocated context. Instead, the options should be passed to
130  * avformat_open_input() wrapped in an AVDictionary:
131  * @code
132  * AVDictionary *options = NULL;
133  * av_dict_set(&options, "video_size", "640x480", 0);
134  * av_dict_set(&options, "pixel_format", "rgb24", 0);
135  *
136  * if (avformat_open_input(&s, url, NULL, &options) < 0)
137  * abort();
138  * av_dict_free(&options);
139  * @endcode
140  * This code passes the private options 'video_size' and 'pixel_format' to the
141  * demuxer. They would be necessary for e.g. the rawvideo demuxer, since it
142  * cannot know how to interpret raw video data otherwise. If the format turns
143  * out to be something different than raw video, those options will not be
144  * recognized by the demuxer and therefore will not be applied. Such unrecognized
145  * options are then returned in the options dictionary (recognized options are
146  * consumed). The calling program can handle such unrecognized options as it
147  * wishes, e.g.
148  * @code
149  * AVDictionaryEntry *e;
150  * if (e = av_dict_get(options, "", NULL, AV_DICT_IGNORE_SUFFIX)) {
151  * fprintf(stderr, "Option %s not recognized by the demuxer.\n", e->key);
152  * abort();
153  * }
154  * @endcode
155  *
156  * After you have finished reading the file, you must close it with
157  * avformat_close_input(). It will free everything associated with the file.
158  *
159  * @section lavf_decoding_read Reading from an opened file
160  * Reading data from an opened AVFormatContext is done by repeatedly calling
161  * av_read_frame() on it. Each call, if successful, will return an AVPacket
162  * containing encoded data for one AVStream, identified by
163  * AVPacket.stream_index. This packet may be passed straight into the libavcodec
164  * decoding functions avcodec_send_packet() or avcodec_decode_subtitle2() if the
165  * caller wishes to decode the data.
166  *
167  * AVPacket.pts, AVPacket.dts and AVPacket.duration timing information will be
168  * set if known. They may also be unset (i.e. AV_NOPTS_VALUE for
169  * pts/dts, 0 for duration) if the stream does not provide them. The timing
170  * information will be in AVStream.time_base units, i.e. it has to be
171  * multiplied by the timebase to convert them to seconds.
172  *
173  * A packet returned by av_read_frame() is always reference-counted,
174  * i.e. AVPacket.buf is set and the user may keep it indefinitely.
175  * The packet must be freed with av_packet_unref() when it is no
176  * longer needed.
177  *
178  * @section lavf_decoding_seek Seeking
179  * @}
180  *
181  * @defgroup lavf_encoding Muxing
182  * @{
183  * Muxers take encoded data in the form of @ref AVPacket "AVPackets" and write
184  * it into files or other output bytestreams in the specified container format.
185  *
186  * The main API functions for muxing are avformat_write_header() for writing the
187  * file header, av_write_frame() / av_interleaved_write_frame() for writing the
188  * packets and av_write_trailer() for finalizing the file.
189  *
190  * At the beginning of the muxing process, the caller must first call
191  * avformat_alloc_context() to create a muxing context. The caller then sets up
192  * the muxer by filling the various fields in this context:
193  *
194  * - The @ref AVFormatContext.oformat "oformat" field must be set to select the
195  * muxer that will be used.
196  * - Unless the format is of the AVFMT_NOFILE type, the @ref AVFormatContext.pb
197  * "pb" field must be set to an opened IO context, either returned from
198  * avio_open2() or a custom one.
199  * - Unless the format is of the AVFMT_NOSTREAMS type, at least one stream must
200  * be created with the avformat_new_stream() function. The caller should fill
201  * the @ref AVStream.codecpar "stream codec parameters" information, such as the
202  * codec @ref AVCodecParameters.codec_type "type", @ref AVCodecParameters.codec_id
203  * "id" and other parameters (e.g. width / height, the pixel or sample format,
204  * etc.) as known. The @ref AVStream.time_base "stream timebase" should
205  * be set to the timebase that the caller desires to use for this stream (note
206  * that the timebase actually used by the muxer can be different, as will be
207  * described later).
208  * - It is advised to manually initialize only the relevant fields in
209  * AVCodecParameters, rather than using @ref avcodec_parameters_copy() during
210  * remuxing: there is no guarantee that the codec context values remain valid
211  * for both input and output format contexts.
212  * - The caller may fill in additional information, such as @ref
213  * AVFormatContext.metadata "global" or @ref AVStream.metadata "per-stream"
214  * metadata, @ref AVFormatContext.chapters "chapters", @ref
215  * AVFormatContext.programs "programs", etc. as described in the
216  * AVFormatContext documentation. Whether such information will actually be
217  * stored in the output depends on what the container format and the muxer
218  * support.
219  *
220  * When the muxing context is fully set up, the caller must call
221  * avformat_write_header() to initialize the muxer internals and write the file
222  * header. Whether anything actually is written to the IO context at this step
223  * depends on the muxer, but this function must always be called. Any muxer
224  * private options must be passed in the options parameter to this function.
225  *
226  * The data is then sent to the muxer by repeatedly calling av_write_frame() or
227  * av_interleaved_write_frame() (consult those functions' documentation for
228  * discussion on the difference between them; only one of them may be used with
229  * a single muxing context, they should not be mixed). Do note that the timing
230  * information on the packets sent to the muxer must be in the corresponding
231  * AVStream's timebase. That timebase is set by the muxer (in the
232  * avformat_write_header() step) and may be different from the timebase
233  * requested by the caller.
234  *
235  * Once all the data has been written, the caller must call av_write_trailer()
236  * to flush any buffered packets and finalize the output file, then close the IO
237  * context (if any) and finally free the muxing context with
238  * avformat_free_context().
239  * @}
240  *
241  * @defgroup lavf_io I/O Read/Write
242  * @{
243  * @section lavf_io_dirlist Directory listing
244  * The directory listing API makes it possible to list files on remote servers.
245  *
246  * Some of possible use cases:
247  * - an "open file" dialog to choose files from a remote location,
248  * - a recursive media finder providing a player with an ability to play all
249  * files from a given directory.
250  *
251  * @subsection lavf_io_dirlist_open Opening a directory
252  * At first, a directory needs to be opened by calling avio_open_dir()
253  * supplied with a URL and, optionally, ::AVDictionary containing
254  * protocol-specific parameters. The function returns zero or positive
255  * integer and allocates AVIODirContext on success.
256  *
257  * @code
258  * AVIODirContext *ctx = NULL;
259  * if (avio_open_dir(&ctx, "smb://example.com/some_dir", NULL) < 0) {
260  * fprintf(stderr, "Cannot open directory.\n");
261  * abort();
262  * }
263  * @endcode
264  *
265  * This code tries to open a sample directory using smb protocol without
266  * any additional parameters.
267  *
268  * @subsection lavf_io_dirlist_read Reading entries
269  * Each directory's entry (i.e. file, another directory, anything else
270  * within ::AVIODirEntryType) is represented by AVIODirEntry.
271  * Reading consecutive entries from an opened AVIODirContext is done by
272  * repeatedly calling avio_read_dir() on it. Each call returns zero or
273  * positive integer if successful. Reading can be stopped right after the
274  * NULL entry has been read -- it means there are no entries left to be
275  * read. The following code reads all entries from a directory associated
276  * with ctx and prints their names to standard output.
277  * @code
278  * AVIODirEntry *entry = NULL;
279  * for (;;) {
280  * if (avio_read_dir(ctx, &entry) < 0) {
281  * fprintf(stderr, "Cannot list directory.\n");
282  * abort();
283  * }
284  * if (!entry)
285  * break;
286  * printf("%s\n", entry->name);
287  * avio_free_directory_entry(&entry);
288  * }
289  * @endcode
290  * @}
291  *
292  * @defgroup lavf_codec Demuxers
293  * @{
294  * @defgroup lavf_codec_native Native Demuxers
295  * @{
296  * @}
297  * @defgroup lavf_codec_wrappers External library wrappers
298  * @{
299  * @}
300  * @}
301  * @defgroup lavf_protos I/O Protocols
302  * @{
303  * @}
304  * @defgroup lavf_internal Internal
305  * @{
306  * @}
307  * @}
308  */
309 
310 #include <time.h>
311 #include <stdio.h> /* FILE */
312 #include "libavcodec/avcodec.h"
313 #include "libavutil/dict.h"
314 #include "libavutil/log.h"
315 
316 #include "avio.h"
317 #include "libavformat/version.h"
318 
319 struct AVFormatContext;
320 
321 struct AVDeviceInfoList;
323 
324 /**
325  * @defgroup metadata_api Public Metadata API
326  * @{
327  * @ingroup libavf
328  * The metadata API allows libavformat to export metadata tags to a client
329  * application when demuxing. Conversely it allows a client application to
330  * set metadata when muxing.
331  *
332  * Metadata is exported or set as pairs of key/value strings in the 'metadata'
333  * fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
334  * using the @ref lavu_dict "AVDictionary" API. Like all strings in FFmpeg,
335  * metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
336  * exported by demuxers isn't checked to be valid UTF-8 in most cases.
337  *
338  * Important concepts to keep in mind:
339  * - Keys are unique; there can never be 2 tags with the same key. This is
340  * also meant semantically, i.e., a demuxer should not knowingly produce
341  * several keys that are literally different but semantically identical.
342  * E.g., key=Author5, key=Author6. In this example, all authors must be
343  * placed in the same tag.
344  * - Metadata is flat, not hierarchical; there are no subtags. If you
345  * want to store, e.g., the email address of the child of producer Alice
346  * and actor Bob, that could have key=alice_and_bobs_childs_email_address.
347  * - Several modifiers can be applied to the tag name. This is done by
348  * appending a dash character ('-') and the modifier name in the order
349  * they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
350  * - language -- a tag whose value is localized for a particular language
351  * is appended with the ISO 639-2/B 3-letter language code.
352  * For example: Author-ger=Michael, Author-eng=Mike
353  * The original/default language is in the unqualified "Author" tag.
354  * A demuxer should set a default if it sets any translated tag.
355  * - sorting -- a modified version of a tag that should be used for
356  * sorting will have '-sort' appended. E.g. artist="The Beatles",
357  * artist-sort="Beatles, The".
358  * - Some protocols and demuxers support metadata updates. After a successful
359  * call to av_read_frame(), AVFormatContext.event_flags or AVStream.event_flags
360  * will be updated to indicate if metadata changed. In order to detect metadata
361  * changes on a stream, you need to loop through all streams in the AVFormatContext
362  * and check their individual event_flags.
363  *
364  * - Demuxers attempt to export metadata in a generic format, however tags
365  * with no generic equivalents are left as they are stored in the container.
366  * Follows a list of generic tag names:
367  *
368  @verbatim
369  album -- name of the set this work belongs to
370  album_artist -- main creator of the set/album, if different from artist.
371  e.g. "Various Artists" for compilation albums.
372  artist -- main creator of the work
373  comment -- any additional description of the file.
374  composer -- who composed the work, if different from artist.
375  copyright -- name of copyright holder.
376  creation_time-- date when the file was created, preferably in ISO 8601.
377  date -- date when the work was created, preferably in ISO 8601.
378  disc -- number of a subset, e.g. disc in a multi-disc collection.
379  encoder -- name/settings of the software/hardware that produced the file.
380  encoded_by -- person/group who created the file.
381  filename -- original name of the file.
382  genre -- <self-evident>.
383  language -- main language in which the work is performed, preferably
384  in ISO 639-2 format. Multiple languages can be specified by
385  separating them with commas.
386  performer -- artist who performed the work, if different from artist.
387  E.g for "Also sprach Zarathustra", artist would be "Richard
388  Strauss" and performer "London Philharmonic Orchestra".
389  publisher -- name of the label/publisher.
390  service_name -- name of the service in broadcasting (channel name).
391  service_provider -- name of the service provider in broadcasting.
392  title -- name of the work.
393  track -- number of this work in the set, can be in form current/total.
394  variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
395  @endverbatim
396  *
397  * Look in the examples section for an application example how to use the Metadata API.
398  *
399  * @}
400  */
401 
402 /* packet functions */
403 
404 
405 /**
406  * Allocate and read the payload of a packet and initialize its
407  * fields with default values.
408  *
409  * @param s associated IO context
410  * @param pkt packet
411  * @param size desired payload size
412  * @return >0 (read size) if OK, AVERROR_xxx otherwise
413  */
415 
416 
417 /**
418  * Read data and append it to the current content of the AVPacket.
419  * If pkt->size is 0 this is identical to av_get_packet.
420  * Note that this uses av_grow_packet and thus involves a realloc
421  * which is inefficient. Thus this function should only be used
422  * when there is no reasonable way to know (an upper bound of)
423  * the final size.
424  *
425  * @param s associated IO context
426  * @param pkt packet
427  * @param size amount of data to read
428  * @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
429  * will not be lost even if an error occurs.
430  */
432 
433 /*************************************************/
434 /* input/output formats */
435 
436 struct AVCodecTag;
437 
438 /**
439  * This structure contains the data a format has to probe a file.
440  */
441 typedef struct AVProbeData {
442  const char *filename;
443  unsigned char *buf; /**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */
444  int buf_size; /**< Size of buf except extra allocated bytes */
445  const char *mime_type; /**< mime_type, when known. */
446 } AVProbeData;
447 
448 #define AVPROBE_SCORE_RETRY (AVPROBE_SCORE_MAX/4)
449 #define AVPROBE_SCORE_STREAM_RETRY (AVPROBE_SCORE_MAX/4-1)
450 
451 #define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
452 #define AVPROBE_SCORE_MIME 75 ///< score for file mime type
453 #define AVPROBE_SCORE_MAX 100 ///< maximum score
454 
455 #define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
456 
457 /// Demuxer will use avio_open, no opened file should be provided by the caller.
458 #define AVFMT_NOFILE 0x0001
459 #define AVFMT_NEEDNUMBER 0x0002 /**< Needs '%d' in filename. */
460 #define AVFMT_SHOW_IDS 0x0008 /**< Show format stream IDs numbers. */
461 #define AVFMT_GLOBALHEADER 0x0040 /**< Format wants global header. */
462 #define AVFMT_NOTIMESTAMPS 0x0080 /**< Format does not need / have any timestamps. */
463 #define AVFMT_GENERIC_INDEX 0x0100 /**< Use generic index building code. */
464 #define AVFMT_TS_DISCONT 0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
465 #define AVFMT_VARIABLE_FPS 0x0400 /**< Format allows variable fps. */
466 #define AVFMT_NODIMENSIONS 0x0800 /**< Format does not need width/height */
467 #define AVFMT_NOSTREAMS 0x1000 /**< Format does not require any streams */
468 #define AVFMT_NOBINSEARCH 0x2000 /**< Format does not allow to fall back on binary search via read_timestamp */
469 #define AVFMT_NOGENSEARCH 0x4000 /**< Format does not allow to fall back on generic search */
470 #define AVFMT_NO_BYTE_SEEK 0x8000 /**< Format does not allow seeking by bytes */
471 #define AVFMT_ALLOW_FLUSH 0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
472 #define AVFMT_TS_NONSTRICT 0x20000 /**< Format does not require strictly
473  increasing timestamps, but they must
474  still be monotonic */
475 #define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative
476  timestamps. If not set the timestamp
477  will be shifted in av_write_frame and
478  av_interleaved_write_frame so they
479  start from 0.
480  The user or muxer can override this through
481  AVFormatContext.avoid_negative_ts
482  */
483 
484 #define AVFMT_SEEK_TO_PTS 0x4000000 /**< Seeking is based on PTS */
485 
486 /**
487  * @addtogroup lavf_encoding
488  * @{
489  */
490 typedef struct AVOutputFormat {
491  const char *name;
492  /**
493  * Descriptive name for the format, meant to be more human-readable
494  * than name. You should use the NULL_IF_CONFIG_SMALL() macro
495  * to define it.
496  */
497  const char *long_name;
498  const char *mime_type;
499  const char *extensions; /**< comma-separated filename extensions */
500  /* output support */
501  enum AVCodecID audio_codec; /**< default audio codec */
502  enum AVCodecID video_codec; /**< default video codec */
503  enum AVCodecID subtitle_codec; /**< default subtitle codec */
504  /**
505  * can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER,
506  * AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
507  * AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
508  * AVFMT_TS_NONSTRICT, AVFMT_TS_NEGATIVE
509  */
510  int flags;
511 
512  /**
513  * List of supported codec_id-codec_tag pairs, ordered by "better
514  * choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
515  */
516  const struct AVCodecTag * const *codec_tag;
517 
518 
519  const AVClass *priv_class; ///< AVClass for the private context
520 
521  /*****************************************************************
522  * No fields below this line are part of the public API. They
523  * may not be used outside of libavformat and can be changed and
524  * removed at will.
525  * New public fields should be added right above.
526  *****************************************************************
527  */
528  /**
529  * size of private data so that it can be allocated in the wrapper
530  */
532 
534  /**
535  * Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,
536  * pkt can be NULL in order to flush data buffered in the muxer.
537  * When flushing, return 0 if there still is more data to flush,
538  * or 1 if everything was flushed and there is no more buffered
539  * data.
540  */
543  /**
544  * A format-specific function for interleavement.
545  * If unset, packets will be interleaved by dts.
546  */
548  AVPacket *in, int flush);
549  /**
550  * Test if the given codec can be stored in this container.
551  *
552  * @return 1 if the codec is supported, 0 if it is not.
553  * A negative number if unknown.
554  * MKTAG('A', 'P', 'I', 'C') if the codec is only supported as AV_DISPOSITION_ATTACHED_PIC
555  */
556  int (*query_codec)(enum AVCodecID id, int std_compliance);
557 
558  void (*get_output_timestamp)(struct AVFormatContext *s, int stream,
559  int64_t *dts, int64_t *wall);
560  /**
561  * Allows sending messages from application to device.
562  */
564  void *data, size_t data_size);
565 
566  /**
567  * Write an uncoded AVFrame.
568  *
569  * See av_write_uncoded_frame() for details.
570  *
571  * The library will free *frame afterwards, but the muxer can prevent it
572  * by setting the pointer to NULL.
573  */
574  int (*write_uncoded_frame)(struct AVFormatContext *, int stream_index,
575  AVFrame **frame, unsigned flags);
576  /**
577  * Returns device list with it properties.
578  * @see avdevice_list_devices() for more details.
579  */
580  int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list);
581  enum AVCodecID data_codec; /**< default data codec */
582  /**
583  * Initialize format. May allocate data here, and set any AVFormatContext or
584  * AVStream parameters that need to be set before packets are sent.
585  * This method must not write output.
586  *
587  * Return 0 if streams were fully configured, 1 if not, negative AVERROR on failure
588  *
589  * Any allocations made here must be freed in deinit().
590  */
591  int (*init)(struct AVFormatContext *);
592  /**
593  * Deinitialize format. If present, this is called whenever the muxer is being
594  * destroyed, regardless of whether or not the header has been written.
595  *
596  * If a trailer is being written, this is called after write_trailer().
597  *
598  * This is called if init() fails as well.
599  */
600  void (*deinit)(struct AVFormatContext *);
601  /**
602  * Set up any necessary bitstream filtering and extract any extra data needed
603  * for the global header.
604  * Return 0 if more packets from this stream must be checked; 1 if not.
605  */
608 /**
609  * @}
610  */
611 
612 /**
613  * @addtogroup lavf_decoding
614  * @{
615  */
616 typedef struct AVInputFormat {
617  /**
618  * A comma separated list of short names for the format. New names
619  * may be appended with a minor bump.
620  */
621  const char *name;
622 
623  /**
624  * Descriptive name for the format, meant to be more human-readable
625  * than name. You should use the NULL_IF_CONFIG_SMALL() macro
626  * to define it.
627  */
628  const char *long_name;
629 
630  /**
631  * Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
632  * AVFMT_NOTIMESTAMPS, AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
633  * AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK, AVFMT_SEEK_TO_PTS.
634  */
635  int flags;
636 
637  /**
638  * If extensions are defined, then no probe is done. You should
639  * usually not use extension format guessing because it is not
640  * reliable enough
641  */
642  const char *extensions;
643 
644  const struct AVCodecTag * const *codec_tag;
645 
646  const AVClass *priv_class; ///< AVClass for the private context
647 
648  /**
649  * Comma-separated list of mime types.
650  * It is used check for matching mime types while probing.
651  * @see av_probe_input_format2
652  */
653  const char *mime_type;
654 
655  /*****************************************************************
656  * No fields below this line are part of the public API. They
657  * may not be used outside of libavformat and can be changed and
658  * removed at will.
659  * New public fields should be added right above.
660  *****************************************************************
661  */
662  /**
663  * Raw demuxers store their codec ID here.
664  */
666 
667  /**
668  * Size of private data so that it can be allocated in the wrapper.
669  */
671 
672  /**
673  * Tell if a given file has a chance of being parsed as this format.
674  * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
675  * big so you do not have to check for that unless you need more.
676  */
678 
679  /**
680  * Read the format header and initialize the AVFormatContext
681  * structure. Return 0 if OK. 'avformat_new_stream' should be
682  * called to create new streams.
683  */
685 
686  /**
687  * Read one packet and put it in 'pkt'. pts and flags are also
688  * set. 'avformat_new_stream' can be called only if the flag
689  * AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
690  * background thread).
691  * @return 0 on success, < 0 on error.
692  * Upon returning an error, pkt must be unreferenced by the caller.
693  */
695 
696  /**
697  * Close the stream. The AVFormatContext and AVStreams are not
698  * freed by this function
699  */
701 
702  /**
703  * Seek to a given timestamp relative to the frames in
704  * stream component stream_index.
705  * @param stream_index Must not be -1.
706  * @param flags Selects which direction should be preferred if no exact
707  * match is available.
708  * @return >= 0 on success (but not necessarily the new offset)
709  */
711  int stream_index, int64_t timestamp, int flags);
712 
713  /**
714  * Get the next timestamp in stream[stream_index].time_base units.
715  * @return the timestamp or AV_NOPTS_VALUE if an error occurred
716  */
717  int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index,
718  int64_t *pos, int64_t pos_limit);
719 
720  /**
721  * Start/resume playing - only meaningful if using a network-based format
722  * (RTSP).
723  */
725 
726  /**
727  * Pause playing - only meaningful if using a network-based format
728  * (RTSP).
729  */
731 
732  /**
733  * Seek to timestamp ts.
734  * Seeking will be done so that the point from which all active streams
735  * can be presented successfully will be closest to ts and within min/max_ts.
736  * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
737  */
738  int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
739 
740  /**
741  * Returns device list with it properties.
742  * @see avdevice_list_devices() for more details.
743  */
744  int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list);
745 
746 } AVInputFormat;
747 /**
748  * @}
749  */
750 
753  AVSTREAM_PARSE_FULL, /**< full parsing and repack */
754  AVSTREAM_PARSE_HEADERS, /**< Only parse headers, do not repack. */
755  AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */
756  AVSTREAM_PARSE_FULL_ONCE, /**< full parsing and repack of the first frame only, only implemented for H.264 currently */
757  AVSTREAM_PARSE_FULL_RAW, /**< full parsing and repack with timestamp and position generation by parser for raw
758  this assumes that each packet in the file contains no demuxer level headers and
759  just codec level data, otherwise position generation would fail */
760 };
761 
762 typedef struct AVIndexEntry {
763  int64_t pos;
764  int64_t timestamp; /**<
765  * Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are available
766  * when seeking to this entry. That means preferable PTS on keyframe based formats.
767  * But demuxers can choose to store a different timestamp, if it is more convenient for the implementation or nothing better
768  * is known
769  */
770 #define AVINDEX_KEYFRAME 0x0001
771 #define AVINDEX_DISCARD_FRAME 0x0002 /**
772  * Flag is used to indicate which frame should be discarded after decoding.
773  */
774  int flags:2;
775  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).
776  int min_distance; /**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */
778 
779 #define AV_DISPOSITION_DEFAULT 0x0001
780 #define AV_DISPOSITION_DUB 0x0002
781 #define AV_DISPOSITION_ORIGINAL 0x0004
782 #define AV_DISPOSITION_COMMENT 0x0008
783 #define AV_DISPOSITION_LYRICS 0x0010
784 #define AV_DISPOSITION_KARAOKE 0x0020
785 
786 /**
787  * Track should be used during playback by default.
788  * Useful for subtitle track that should be displayed
789  * even when user did not explicitly ask for subtitles.
790  */
791 #define AV_DISPOSITION_FORCED 0x0040
792 #define AV_DISPOSITION_HEARING_IMPAIRED 0x0080 /**< stream for hearing impaired audiences */
793 #define AV_DISPOSITION_VISUAL_IMPAIRED 0x0100 /**< stream for visual impaired audiences */
794 #define AV_DISPOSITION_CLEAN_EFFECTS 0x0200 /**< stream without voice */
795 /**
796  * The stream is stored in the file as an attached picture/"cover art" (e.g.
797  * APIC frame in ID3v2). The first (usually only) packet associated with it
798  * will be returned among the first few packets read from the file unless
799  * seeking takes place. It can also be accessed at any time in
800  * AVStream.attached_pic.
801  */
802 #define AV_DISPOSITION_ATTACHED_PIC 0x0400
803 /**
804  * The stream is sparse, and contains thumbnail images, often corresponding
805  * to chapter markers. Only ever used with AV_DISPOSITION_ATTACHED_PIC.
806  */
807 #define AV_DISPOSITION_TIMED_THUMBNAILS 0x0800
808 
809 typedef struct AVStreamInternal AVStreamInternal;
810 
811 /**
812  * To specify text track kind (different from subtitles default).
813  */
814 #define AV_DISPOSITION_CAPTIONS 0x10000
815 #define AV_DISPOSITION_DESCRIPTIONS 0x20000
816 #define AV_DISPOSITION_METADATA 0x40000
817 #define AV_DISPOSITION_DEPENDENT 0x80000 ///< dependent audio stream (mix_type=0 in mpegts)
818 #define AV_DISPOSITION_STILL_IMAGE 0x100000 ///< still images in video stream (still_picture_flag=1 in mpegts)
819 
820 /**
821  * Options for behavior on timestamp wrap detection.
822  */
823 #define AV_PTS_WRAP_IGNORE 0 ///< ignore the wrap
824 #define AV_PTS_WRAP_ADD_OFFSET 1 ///< add the format specific offset on wrap detection
825 #define AV_PTS_WRAP_SUB_OFFSET -1 ///< subtract the format specific offset on wrap detection
826 
827 /**
828  * Stream structure.
829  * New fields can be added to the end with minor version bumps.
830  * Removal, reordering and changes to existing fields require a major
831  * version bump.
832  * sizeof(AVStream) must not be used outside libav*.
833  */
834 typedef struct AVStream {
835  int index; /**< stream index in AVFormatContext */
836  /**
837  * Format-specific stream ID.
838  * decoding: set by libavformat
839  * encoding: set by the user, replaced by libavformat if left unset
840  */
841  int id;
842 
843  void *priv_data;
844 
845  /**
846  * This is the fundamental unit of time (in seconds) in terms
847  * of which frame timestamps are represented.
848  *
849  * decoding: set by libavformat
850  * encoding: May be set by the caller before avformat_write_header() to
851  * provide a hint to the muxer about the desired timebase. In
852  * avformat_write_header(), the muxer will overwrite this field
853  * with the timebase that will actually be used for the timestamps
854  * written into the file (which may or may not be related to the
855  * user-provided one, depending on the format).
856  */
858 
859  /**
860  * Decoding: pts of the first frame of the stream in presentation order, in stream time base.
861  * Only set this if you are absolutely 100% sure that the value you set
862  * it to really is the pts of the first frame.
863  * This may be undefined (AV_NOPTS_VALUE).
864  * @note The ASF header does NOT contain a correct start_time the ASF
865  * demuxer must NOT set this.
866  */
867  int64_t start_time;
868 
869  /**
870  * Decoding: duration of the stream, in stream time base.
871  * If a source file does not specify a duration, but does specify
872  * a bitrate, this value will be estimated from bitrate and file size.
873  *
874  * Encoding: May be set by the caller before avformat_write_header() to
875  * provide a hint to the muxer about the estimated duration.
876  */
877  int64_t duration;
878 
879  int64_t nb_frames; ///< number of frames in this stream if known or 0
880 
881  int disposition; /**< AV_DISPOSITION_* bit field */
882 
883  enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
884 
885  /**
886  * sample aspect ratio (0 if unknown)
887  * - encoding: Set by user.
888  * - decoding: Set by libavformat.
889  */
891 
893 
894  /**
895  * Average framerate
896  *
897  * - demuxing: May be set by libavformat when creating the stream or in
898  * avformat_find_stream_info().
899  * - muxing: May be set by the caller before avformat_write_header().
900  */
902 
903  /**
904  * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
905  * will contain the attached picture.
906  *
907  * decoding: set by libavformat, must not be modified by the caller.
908  * encoding: unused
909  */
911 
912  /**
913  * An array of side data that applies to the whole stream (i.e. the
914  * container does not allow it to change between packets).
915  *
916  * There may be no overlap between the side data in this array and side data
917  * in the packets. I.e. a given side data is either exported by the muxer
918  * (demuxing) / set by the caller (muxing) in this array, then it never
919  * appears in the packets, or the side data is exported / sent through
920  * the packets (always in the first packet where the value becomes known or
921  * changes), then it does not appear in this array.
922  *
923  * - demuxing: Set by libavformat when the stream is created.
924  * - muxing: May be set by the caller before avformat_write_header().
925  *
926  * Freed by libavformat in avformat_free_context().
927  *
928  * @see av_format_inject_global_side_data()
929  */
931  /**
932  * The number of elements in the AVStream.side_data array.
933  */
934  int nb_side_data;
935 
936  /**
937  * Flags indicating events happening on the stream, a combination of
938  * AVSTREAM_EVENT_FLAG_*.
939  *
940  * - demuxing: may be set by the demuxer in avformat_open_input(),
941  * avformat_find_stream_info() and av_read_frame(). Flags must be cleared
942  * by the user once the event has been handled.
943  * - muxing: may be set by the user after avformat_write_header(). to
944  * indicate a user-triggered event. The muxer will clear the flags for
945  * events it has handled in av_[interleaved]_write_frame().
946  */
947  int event_flags;
948 /**
949  * - demuxing: the demuxer read new metadata from the file and updated
950  * AVStream.metadata accordingly
951  * - muxing: the user updated AVStream.metadata and wishes the muxer to write
952  * it into the file
953  */
954 #define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001
955 /**
956  * - demuxing: new packets for this stream were read from the file. This
957  * event is informational only and does not guarantee that new packets
958  * for this stream will necessarily be returned from av_read_frame().
959  */
960 #define AVSTREAM_EVENT_FLAG_NEW_PACKETS (1 << 1)
961 
962  /**
963  * Real base framerate of the stream.
964  * This is the lowest framerate with which all timestamps can be
965  * represented accurately (it is the least common multiple of all
966  * framerates in the stream). Note, this value is just a guess!
967  * For example, if the time base is 1/90000 and all frames have either
968  * approximately 3600 or 1800 timer ticks, then r_frame_rate will be 50/1.
969  */
971 
972  /**
973  * Codec parameters associated with this stream. Allocated and freed by
974  * libavformat in avformat_new_stream() and avformat_free_context()
975  * respectively.
976  *
977  * - demuxing: filled by libavformat on stream creation or in
978  * avformat_find_stream_info()
979  * - muxing: filled by the caller before avformat_write_header()
980  */
982 
983  /*****************************************************************
984  * All fields below this line are not part of the public API. They
985  * may not be used outside of libavformat and can be changed and
986  * removed at will.
987  * Internal note: be aware that physically removing these fields
988  * will break ABI. Replace removed fields with dummy fields, and
989  * add new fields to AVStreamInternal.
990  *****************************************************************
991  */
992 
993  int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
994 
995  // Timestamp generation support:
996  /**
997  * Timestamp corresponding to the last dts sync point.
998  *
999  * Initialized when AVCodecParserContext.dts_sync_point >= 0 and
1000  * a DTS is received from the underlying container. Otherwise set to
1001  * AV_NOPTS_VALUE by default.
1002  */
1003  int64_t first_dts;
1004  int64_t cur_dts;
1005 
1006  /**
1007  * An opaque field for libavformat internal usage.
1008  * Must not be accessed in any way by callers.
1009  */
1010  AVStreamInternal *internal;
1011 } AVStream;
1012 
1014 
1015 /**
1016  * Returns the pts of the last muxed packet + its duration
1017  *
1018  * the retuned value is undefined when used with a demuxer.
1019  */
1020 int64_t av_stream_get_end_pts(const AVStream *st);
1021 
1022 #define AV_PROGRAM_RUNNING 1
1023 
1024 /**
1025  * New fields can be added to the end with minor version bumps.
1026  * Removal, reordering and changes to existing fields require a major
1027  * version bump.
1028  * sizeof(AVProgram) must not be used outside libav*.
1029  */
1030 typedef struct AVProgram {
1031  int id;
1032  int flags;
1033  enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
1034  unsigned int *stream_index;
1035  unsigned int nb_stream_indexes;
1039  int pmt_pid;
1040  int pcr_pid;
1041  int pmt_version;
1042 
1043  /*****************************************************************
1044  * All fields below this line are not part of the public API. They
1045  * may not be used outside of libavformat and can be changed and
1046  * removed at will.
1047  * New public fields should be added right above.
1048  *****************************************************************
1049  */
1050  int64_t start_time;
1051  int64_t end_time;
1053  int64_t pts_wrap_reference; ///< reference dts for wrap detection
1054  int pts_wrap_behavior; ///< behavior on wrap detection
1056 
1057 #define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
1058  (streams are added dynamically) */
1059 #define AVFMTCTX_UNSEEKABLE 0x0002 /**< signal that the stream is definitely
1060  not seekable, and attempts to call the
1061  seek function will fail. For some
1062  network protocols (e.g. HLS), this can
1063  change dynamically at runtime. */
1065 typedef struct AVChapter {
1066  int64_t id; ///< unique ID to identify the chapter
1067  AVRational time_base; ///< time base in which the start/end timestamps are specified
1068  int64_t start, end; ///< chapter start/end time in time_base units
1070 } AVChapter;
1071 
1072 
1073 /**
1074  * Callback used by devices to communicate with application.
1075  */
1076 typedef int (*av_format_control_message)(struct AVFormatContext *s, int type,
1077  void *data, size_t data_size);
1078 
1079 typedef int (*AVOpenCallback)(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags,
1081 
1082 /**
1083  * The duration of a video can be estimated through various ways, and this enum can be used
1084  * to know how the duration was estimated.
1085  */
1087  AVFMT_DURATION_FROM_PTS, ///< Duration accurately estimated from PTSes
1088  AVFMT_DURATION_FROM_STREAM, ///< Duration estimated from a stream with a known duration
1089  AVFMT_DURATION_FROM_BITRATE ///< Duration estimated from bitrate (less accurate)
1090 };
1091 
1092 typedef struct AVFormatInternal AVFormatInternal;
1093 
1094 /**
1095  * Format I/O context.
1096  * New fields can be added to the end with minor version bumps.
1097  * Removal, reordering and changes to existing fields require a major
1098  * version bump.
1099  * sizeof(AVFormatContext) must not be used outside libav*, use
1100  * avformat_alloc_context() to create an AVFormatContext.
1101  *
1102  * Fields can be accessed through AVOptions (av_opt*),
1103  * the name string used matches the associated command line parameter name and
1104  * can be found in libavformat/options_table.h.
1105  * The AVOption/command line parameter names differ in some cases from the C
1106  * structure field names for historic reasons or brevity.
1107  */
1108 typedef struct AVFormatContext {
1109  /**
1110  * A class for logging and @ref avoptions. Set by avformat_alloc_context().
1111  * Exports (de)muxer private options if they exist.
1112  */
1113  const AVClass *av_class;
1114 
1115  /**
1116  * The input container format.
1117  *
1118  * Demuxing only, set by avformat_open_input().
1119  */
1120  const struct AVInputFormat *iformat;
1121 
1122  /**
1123  * The output container format.
1124  *
1125  * Muxing only, must be set by the caller before avformat_write_header().
1126  */
1127  const struct AVOutputFormat *oformat;
1128 
1129  /**
1130  * Format private data. This is an AVOptions-enabled struct
1131  * if and only if iformat/oformat.priv_class is not NULL.
1132  *
1133  * - muxing: set by avformat_write_header()
1134  * - demuxing: set by avformat_open_input()
1135  */
1136  void *priv_data;
1137 
1138  /**
1139  * I/O context.
1140  *
1141  * - demuxing: either set by the user before avformat_open_input() (then
1142  * the user must close it manually) or set by avformat_open_input().
1143  * - muxing: set by the user before avformat_write_header(). The caller must
1144  * take care of closing / freeing the IO context.
1145  *
1146  * Do NOT set this field if AVFMT_NOFILE flag is set in
1147  * iformat/oformat.flags. In such a case, the (de)muxer will handle
1148  * I/O in some other way and this field will be NULL.
1149  */
1150  AVIOContext *pb;
1151 
1152  /* stream info */
1153  /**
1154  * Flags signalling stream properties. A combination of AVFMTCTX_*.
1155  * Set by libavformat.
1156  */
1157  int ctx_flags;
1158 
1159  /**
1160  * Number of elements in AVFormatContext.streams.
1161  *
1162  * Set by avformat_new_stream(), must not be modified by any other code.
1163  */
1164  unsigned int nb_streams;
1165  /**
1166  * A list of all streams in the file. New streams are created with
1167  * avformat_new_stream().
1168  *
1169  * - demuxing: streams are created by libavformat in avformat_open_input().
1170  * If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
1171  * appear in av_read_frame().
1172  * - muxing: streams are created by the user before avformat_write_header().
1173  *
1174  * Freed by libavformat in avformat_free_context().
1175  */
1176  AVStream **streams;
1177 
1178  /**
1179  * input or output URL. Unlike the old filename field, this field has no
1180  * length restriction.
1181  *
1182  * - demuxing: set by avformat_open_input(), initialized to an empty
1183  * string if url parameter was NULL in avformat_open_input().
1184  * - muxing: may be set by the caller before calling avformat_write_header()
1185  * (or avformat_init_output() if that is called first) to a string
1186  * which is freeable by av_free(). Set to an empty string if it
1187  * was NULL in avformat_init_output().
1188  *
1189  * Freed by libavformat in avformat_free_context().
1190  */
1191  char *url;
1192 
1193  /**
1194  * Position of the first frame of the component, in
1195  * AV_TIME_BASE fractional seconds. NEVER set this value directly:
1196  * It is deduced from the AVStream values.
1197  *
1198  * Demuxing only, set by libavformat.
1199  */
1200  int64_t start_time;
1201 
1202  /**
1203  * Duration of the stream, in AV_TIME_BASE fractional
1204  * seconds. Only set this value if you know none of the individual stream
1205  * durations and also do not set any of them. This is deduced from the
1206  * AVStream values if not set.
1207  *
1208  * Demuxing only, set by libavformat.
1209  */
1210  int64_t duration;
1211 
1212  /**
1213  * Total stream bitrate in bit/s, 0 if not
1214  * available. Never set it directly if the file_size and the
1215  * duration are known as FFmpeg can compute it automatically.
1216  */
1217  int64_t bit_rate;
1219  unsigned int packet_size;
1220  int max_delay;
1221 
1222  /**
1223  * Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
1224  * Set by the user before avformat_open_input() / avformat_write_header().
1225  */
1226  int flags;
1227 #define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
1228 #define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
1229 #define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
1230 #define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
1231 #define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container
1232 #define AVFMT_FLAG_NOPARSE 0x0020 ///< Do not use AVParsers, you also must set AVFMT_FLAG_NOFILLIN as the fillin code works on frames and no parsing -> no frames. Also seeking to frames can not work if parsing to find frame boundaries has been disabled
1233 #define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
1234 #define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
1235 #define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
1236 #define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
1237 /**
1238  * When muxing, try to avoid writing any random/volatile data to the output.
1239  * This includes any random IDs, real-time timestamps/dates, muxer version, etc.
1240  *
1241  * This flag is mainly intended for testing.
1242  */
1243 #define AVFMT_FLAG_BITEXACT 0x0400
1244 #define AVFMT_FLAG_SORT_DTS 0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
1245 #if FF_API_LAVF_PRIV_OPT
1246 #define AVFMT_FLAG_PRIV_OPT 0x20000 ///< Enable use of private options by delaying codec open (deprecated, does nothing)
1247 #endif
1248 #define AVFMT_FLAG_FAST_SEEK 0x80000 ///< Enable fast, but inaccurate seeks for some formats
1249 #define AVFMT_FLAG_SHORTEST 0x100000 ///< Stop muxing when the shortest stream stops.
1250 #define AVFMT_FLAG_AUTO_BSF 0x200000 ///< Add bitstream filters as requested by the muxer
1251 
1252  /**
1253  * Maximum size of the data read from input for determining
1254  * the input container format.
1255  * Demuxing only, set by the caller before avformat_open_input().
1256  */
1257  int64_t probesize;
1258 
1259  /**
1260  * Maximum duration (in AV_TIME_BASE units) of the data read
1261  * from input in avformat_find_stream_info().
1262  * Demuxing only, set by the caller before avformat_find_stream_info().
1263  * Can be set to 0 to let avformat choose using a heuristic.
1264  */
1267  const uint8_t *key;
1268  int keylen;
1270  unsigned int nb_programs;
1271  AVProgram **programs;
1272 
1273  /**
1274  * Forced video codec_id.
1275  * Demuxing: Set by user.
1276  */
1278 
1279  /**
1280  * Forced audio codec_id.
1281  * Demuxing: Set by user.
1282  */
1284 
1285  /**
1286  * Forced subtitle codec_id.
1287  * Demuxing: Set by user.
1288  */
1290 
1291  /**
1292  * Maximum amount of memory in bytes to use for the index of each stream.
1293  * If the index exceeds this size, entries will be discarded as
1294  * needed to maintain a smaller size. This can lead to slower or less
1295  * accurate seeking (depends on demuxer).
1296  * Demuxers for which a full in-memory index is mandatory will ignore
1297  * this.
1298  * - muxing: unused
1299  * - demuxing: set by user
1300  */
1301  unsigned int max_index_size;
1302 
1303  /**
1304  * Maximum amount of memory in bytes to use for buffering frames
1305  * obtained from realtime capture devices.
1306  */
1307  unsigned int max_picture_buffer;
1308 
1309  /**
1310  * Number of chapters in AVChapter array.
1311  * When muxing, chapters are normally written in the file header,
1312  * so nb_chapters should normally be initialized before write_header
1313  * is called. Some muxers (e.g. mov and mkv) can also write chapters
1314  * in the trailer. To write chapters in the trailer, nb_chapters
1315  * must be zero when write_header is called and non-zero when
1316  * write_trailer is called.
1317  * - muxing: set by user
1318  * - demuxing: set by libavformat
1319  */
1320  unsigned int nb_chapters;
1321  AVChapter **chapters;
1322 
1323  /**
1324  * Metadata that applies to the whole file.
1325  *
1326  * - demuxing: set by libavformat in avformat_open_input()
1327  * - muxing: may be set by the caller before avformat_write_header()
1328  *
1329  * Freed by libavformat in avformat_free_context().
1330  */
1332 
1333  /**
1334  * Start time of the stream in real world time, in microseconds
1335  * since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1336  * stream was captured at this real world time.
1337  * - muxing: Set by the caller before avformat_write_header(). If set to
1338  * either 0 or AV_NOPTS_VALUE, then the current wall-time will
1339  * be used.
1340  * - demuxing: Set by libavformat. AV_NOPTS_VALUE if unknown. Note that
1341  * the value may become known after some number of frames
1342  * have been received.
1343  */
1344  int64_t start_time_realtime;
1345 
1346  /**
1347  * The number of frames used for determining the framerate in
1348  * avformat_find_stream_info().
1349  * Demuxing only, set by the caller before avformat_find_stream_info().
1350  */
1351  int fps_probe_size;
1352 
1353  /**
1354  * Error recognition; higher values will detect more errors but may
1355  * misdetect some more or less valid parts as errors.
1356  * Demuxing only, set by the caller before avformat_open_input().
1357  */
1358  int error_recognition;
1359 
1360  /**
1361  * Custom interrupt callbacks for the I/O layer.
1362  *
1363  * demuxing: set by the user before avformat_open_input().
1364  * muxing: set by the user before avformat_write_header()
1365  * (mainly useful for AVFMT_NOFILE formats). The callback
1366  * should also be passed to avio_open2() if it's used to
1367  * open the file.
1368  */
1370 
1371  /**
1372  * Flags to enable debugging.
1373  */
1374  int debug;
1375 #define FF_FDEBUG_TS 0x0001
1376 
1377  /**
1378  * Maximum buffering duration for interleaving.
1379  *
1380  * To ensure all the streams are interleaved correctly,
1381  * av_interleaved_write_frame() will wait until it has at least one packet
1382  * for each stream before actually writing any packets to the output file.
1383  * When some streams are "sparse" (i.e. there are large gaps between
1384  * successive packets), this can result in excessive buffering.
1385  *
1386  * This field specifies the maximum difference between the timestamps of the
1387  * first and the last packet in the muxing queue, above which libavformat
1388  * will output a packet regardless of whether it has queued a packet for all
1389  * the streams.
1390  *
1391  * Muxing only, set by the caller before avformat_write_header().
1392  */
1393  int64_t max_interleave_delta;
1394 
1395  /**
1396  * Allow non-standard and experimental extension
1397  * @see AVCodecContext.strict_std_compliance
1398  */
1400 
1401  /**
1402  * Flags indicating events happening on the file, a combination of
1403  * AVFMT_EVENT_FLAG_*.
1404  *
1405  * - demuxing: may be set by the demuxer in avformat_open_input(),
1406  * avformat_find_stream_info() and av_read_frame(). Flags must be cleared
1407  * by the user once the event has been handled.
1408  * - muxing: may be set by the user after avformat_write_header() to
1409  * indicate a user-triggered event. The muxer will clear the flags for
1410  * events it has handled in av_[interleaved]_write_frame().
1411  */
1412  int event_flags;
1413 /**
1414  * - demuxing: the demuxer read new metadata from the file and updated
1415  * AVFormatContext.metadata accordingly
1416  * - muxing: the user updated AVFormatContext.metadata and wishes the muxer to
1417  * write it into the file
1418  */
1419 #define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001
1420 
1421  /**
1422  * Maximum number of packets to read while waiting for the first timestamp.
1423  * Decoding only.
1424  */
1425  int max_ts_probe;
1426 
1427  /**
1428  * Avoid negative timestamps during muxing.
1429  * Any value of the AVFMT_AVOID_NEG_TS_* constants.
1430  * Note, this only works when using av_interleaved_write_frame. (interleave_packet_per_dts is in use)
1431  * - muxing: Set by user
1432  * - demuxing: unused
1433  */
1435 #define AVFMT_AVOID_NEG_TS_AUTO -1 ///< Enabled when required by target format
1436 #define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
1437 #define AVFMT_AVOID_NEG_TS_MAKE_ZERO 2 ///< Shift timestamps so that they start at 0
1438 
1439  /**
1440  * Transport stream id.
1441  * This will be moved into demuxer private options. Thus no API/ABI compatibility
1442  */
1443  int ts_id;
1444 
1445  /**
1446  * Audio preload in microseconds.
1447  * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1448  * - encoding: Set by user
1449  * - decoding: unused
1450  */
1451  int audio_preload;
1452 
1453  /**
1454  * Max chunk time in microseconds.
1455  * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1456  * - encoding: Set by user
1457  * - decoding: unused
1458  */
1459  int max_chunk_duration;
1460 
1461  /**
1462  * Max chunk size in bytes
1463  * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1464  * - encoding: Set by user
1465  * - decoding: unused
1466  */
1467  int max_chunk_size;
1468 
1469  /**
1470  * forces the use of wallclock timestamps as pts/dts of packets
1471  * This has undefined results in the presence of B frames.
1472  * - encoding: unused
1473  * - decoding: Set by user
1474  */
1476 
1477  /**
1478  * avio flags, used to force AVIO_FLAG_DIRECT.
1479  * - encoding: unused
1480  * - decoding: Set by user
1481  */
1482  int avio_flags;
1483 
1484  /**
1485  * The duration field can be estimated through various ways, and this field can be used
1486  * to know how the duration was estimated.
1487  * - encoding: unused
1488  * - decoding: Read by user
1489  */
1491 
1492  /**
1493  * Skip initial bytes when opening stream
1494  * - encoding: unused
1495  * - decoding: Set by user
1496  */
1497  int64_t skip_initial_bytes;
1498 
1499  /**
1500  * Correct single timestamp overflows
1501  * - encoding: unused
1502  * - decoding: Set by user
1503  */
1504  unsigned int correct_ts_overflow;
1505 
1506  /**
1507  * Force seeking to any (also non key) frames.
1508  * - encoding: unused
1509  * - decoding: Set by user
1510  */
1511  int seek2any;
1512 
1513  /**
1514  * Flush the I/O context after each packet.
1515  * - encoding: Set by user
1516  * - decoding: unused
1517  */
1518  int flush_packets;
1519 
1520  /**
1521  * format probing score.
1522  * The maximal score is AVPROBE_SCORE_MAX, its set when the demuxer probes
1523  * the format.
1524  * - encoding: unused
1525  * - decoding: set by avformat, read by user
1526  */
1527  int probe_score;
1528 
1529  /**
1530  * number of bytes to read maximally to identify format.
1531  * - encoding: unused
1532  * - decoding: set by user
1533  */
1534  int format_probesize;
1535 
1536  /**
1537  * ',' separated list of allowed decoders.
1538  * If NULL then all are allowed
1539  * - encoding: unused
1540  * - decoding: set by user
1541  */
1542  char *codec_whitelist;
1543 
1544  /**
1545  * ',' separated list of allowed demuxers.
1546  * If NULL then all are allowed
1547  * - encoding: unused
1548  * - decoding: set by user
1549  */
1550  char *format_whitelist;
1551 
1552  /**
1553  * An opaque field for libavformat internal usage.
1554  * Must not be accessed in any way by callers.
1555  */
1556  AVFormatInternal *internal;
1557 
1558  /**
1559  * IO repositioned flag.
1560  * This is set by avformat when the underlaying IO context read pointer
1561  * is repositioned, for example when doing byte based seeking.
1562  * Demuxers can use the flag to detect such changes.
1563  */
1564  int io_repositioned;
1565 
1566  /**
1567  * Forced video codec.
1568  * This allows forcing a specific decoder, even when there are multiple with
1569  * the same codec_id.
1570  * Demuxing: Set by user
1571  */
1572  const AVCodec *video_codec;
1573 
1574  /**
1575  * Forced audio codec.
1576  * This allows forcing a specific decoder, even when there are multiple with
1577  * the same codec_id.
1578  * Demuxing: Set by user
1579  */
1580  const AVCodec *audio_codec;
1581 
1582  /**
1583  * Forced subtitle codec.
1584  * This allows forcing a specific decoder, even when there are multiple with
1585  * the same codec_id.
1586  * Demuxing: Set by user
1587  */
1588  const AVCodec *subtitle_codec;
1589 
1590  /**
1591  * Forced data codec.
1592  * This allows forcing a specific decoder, even when there are multiple with
1593  * the same codec_id.
1594  * Demuxing: Set by user
1595  */
1596  const AVCodec *data_codec;
1597 
1598  /**
1599  * Number of bytes to be written as padding in a metadata header.
1600  * Demuxing: Unused.
1601  * Muxing: Set by user via av_format_set_metadata_header_padding.
1602  */
1604 
1605  /**
1606  * User data.
1607  * This is a place for some private data of the user.
1608  */
1609  void *opaque;
1610 
1611  /**
1612  * Callback used by devices to communicate with application.
1613  */
1615 
1616  /**
1617  * Output timestamp offset, in microseconds.
1618  * Muxing: set by user
1619  */
1620  int64_t output_ts_offset;
1621 
1622  /**
1623  * dump format separator.
1624  * can be ", " or "\n " or anything else
1625  * - muxing: Set by user.
1626  * - demuxing: Set by user.
1627  */
1628  uint8_t *dump_separator;
1629 
1630  /**
1631  * Forced Data codec_id.
1632  * Demuxing: Set by user.
1633  */
1634  enum AVCodecID data_codec_id;
1635 
1636  /**
1637  * ',' separated list of allowed protocols.
1638  * - encoding: unused
1639  * - decoding: set by user
1640  */
1641  char *protocol_whitelist;
1642 
1643  /**
1644  * A callback for opening new IO streams.
1645  *
1646  * Whenever a muxer or a demuxer needs to open an IO stream (typically from
1647  * avformat_open_input() for demuxers, but for certain formats can happen at
1648  * other times as well), it will call this callback to obtain an IO context.
1649  *
1650  * @param s the format context
1651  * @param pb on success, the newly opened IO context should be returned here
1652  * @param url the url to open
1653  * @param flags a combination of AVIO_FLAG_*
1654  * @param options a dictionary of additional options, with the same
1655  * semantics as in avio_open2()
1656  * @return 0 on success, a negative AVERROR code on failure
1657  *
1658  * @note Certain muxers and demuxers do nesting, i.e. they open one or more
1659  * additional internal format contexts. Thus the AVFormatContext pointer
1660  * passed to this callback may be different from the one facing the caller.
1661  * It will, however, have the same 'opaque' field.
1662  */
1663  int (*io_open)(struct AVFormatContext *s, AVIOContext **pb, const char *url,
1664  int flags, AVDictionary **options);
1665 
1666  /**
1667  * A callback for closing the streams opened with AVFormatContext.io_open().
1668  */
1669  void (*io_close)(struct AVFormatContext *s, AVIOContext *pb);
1670 
1671  /**
1672  * ',' separated list of disallowed protocols.
1673  * - encoding: unused
1674  * - decoding: set by user
1675  */
1676  char *protocol_blacklist;
1677 
1678  /**
1679  * The maximum number of streams.
1680  * - encoding: unused
1681  * - decoding: set by user
1682  */
1683  int max_streams;
1684 
1685  /**
1686  * Skip duration calcuation in estimate_timings_from_pts.
1687  * - encoding: unused
1688  * - decoding: set by user
1689  */
1691 
1692  /**
1693  * Maximum number of packets that can be probed
1694  * - encoding: unused
1695  * - decoding: set by user
1696  */
1697  int max_probe_packets;
1698 } AVFormatContext;
1699 
1700 /**
1701  * This function will cause global side data to be injected in the next packet
1702  * of each stream as well as after any subsequent seek.
1703  */
1705 
1706 /**
1707  * Returns the method used to set ctx->duration.
1708  *
1709  * @return AVFMT_DURATION_FROM_PTS, AVFMT_DURATION_FROM_STREAM, or AVFMT_DURATION_FROM_BITRATE.
1710  */
1712 
1713 /**
1714  * @defgroup lavf_core Core functions
1715  * @ingroup libavf
1716  *
1717  * Functions for querying libavformat capabilities, allocating core structures,
1718  * etc.
1719  * @{
1720  */
1721 
1722 /**
1723  * Return the LIBAVFORMAT_VERSION_INT constant.
1724  */
1725 unsigned avformat_version(void);
1726 
1727 /**
1728  * Return the libavformat build-time configuration.
1729  */
1730 const char *avformat_configuration(void);
1731 
1732 /**
1733  * Return the libavformat license.
1734  */
1735 const char *avformat_license(void);
1736 
1737 /**
1738  * Do global initialization of network libraries. This is optional,
1739  * and not recommended anymore.
1740  *
1741  * This functions only exists to work around thread-safety issues
1742  * with older GnuTLS or OpenSSL libraries. If libavformat is linked
1743  * to newer versions of those libraries, or if you do not use them,
1744  * calling this function is unnecessary. Otherwise, you need to call
1745  * this function before any other threads using them are started.
1746  *
1747  * This function will be deprecated once support for older GnuTLS and
1748  * OpenSSL libraries is removed, and this function has no purpose
1749  * anymore.
1750  */
1751 int avformat_network_init(void);
1752 
1753 /**
1754  * Undo the initialization done by avformat_network_init. Call it only
1755  * once for each time you called avformat_network_init.
1756  */
1757 int avformat_network_deinit(void);
1758 
1759 /**
1760  * Iterate over all registered muxers.
1761  *
1762  * @param opaque a pointer where libavformat will store the iteration state. Must
1763  * point to NULL to start the iteration.
1764  *
1765  * @return the next registered muxer or NULL when the iteration is
1766  * finished
1767  */
1768 const AVOutputFormat *av_muxer_iterate(void **opaque);
1769 
1770 /**
1771  * Iterate over all registered demuxers.
1772  *
1773  * @param opaque a pointer where libavformat will store the iteration state. Must
1774  * point to NULL to start the iteration.
1775  *
1776  * @return the next registered demuxer or NULL when the iteration is
1777  * finished
1778  */
1779 const AVInputFormat *av_demuxer_iterate(void **opaque);
1780 
1781 /**
1782  * Allocate an AVFormatContext.
1783  * avformat_free_context() can be used to free the context and everything
1784  * allocated by the framework within it.
1785  */
1787 
1788 /**
1789  * Free an AVFormatContext and all its streams.
1790  * @param s context to free
1791  */
1793 
1794 /**
1795  * Get the AVClass for AVFormatContext. It can be used in combination with
1796  * AV_OPT_SEARCH_FAKE_OBJ for examining options.
1797  *
1798  * @see av_opt_find().
1799  */
1800 const AVClass *avformat_get_class(void);
1801 
1802 /**
1803  * Add a new stream to a media file.
1804  *
1805  * When demuxing, it is called by the demuxer in read_header(). If the
1806  * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
1807  * be called in read_packet().
1808  *
1809  * When muxing, should be called by the user before avformat_write_header().
1810  *
1811  * User is required to call avformat_free_context() to clean up the allocation
1812  * by avformat_new_stream().
1813  *
1814  * @param s media file handle
1815  * @param c unused, does nothing
1816  *
1817  * @return newly created stream or NULL on error.
1818  */
1820 
1821 /**
1822  * Wrap an existing array as stream side data.
1823  *
1824  * @param st stream
1825  * @param type side information type
1826  * @param data the side data array. It must be allocated with the av_malloc()
1827  * family of functions. The ownership of the data is transferred to
1828  * st.
1829  * @param size side information size
1830  * @return zero on success, a negative AVERROR code on failure. On failure,
1831  * the stream is unchanged and the data remains owned by the caller.
1832  */
1834  uint8_t *data, size_t size);
1835 
1836 /**
1837  * Allocate new information from stream.
1838  *
1839  * @param stream stream
1840  * @param type desired side information type
1841  * @param size side information size
1842  * @return pointer to fresh allocated data or NULL otherwise
1843  */
1844 uint8_t *av_stream_new_side_data(AVStream *stream,
1845  enum AVPacketSideDataType type, size_t size);
1846 /**
1847  * Get side information from stream.
1848  *
1849  * @param stream stream
1850  * @param type desired side information type
1851  * @param size If supplied, *size will be set to the size of the side data
1852  * or to zero if the desired side data is not present.
1853  * @return pointer to data if present or NULL otherwise
1854  */
1855 uint8_t *av_stream_get_side_data(const AVStream *stream,
1856  enum AVPacketSideDataType type, size_t *size);
1857 
1859 
1860 /**
1861  * @}
1862  */
1863 
1864 
1865 /**
1866  * Allocate an AVFormatContext for an output format.
1867  * avformat_free_context() can be used to free the context and
1868  * everything allocated by the framework within it.
1869  *
1870  * @param *ctx is set to the created format context, or to NULL in
1871  * case of failure
1872  * @param oformat format to use for allocating the context, if NULL
1873  * format_name and filename are used instead
1874  * @param format_name the name of output format to use for allocating the
1875  * context, if NULL filename is used instead
1876  * @param filename the name of the filename to use for allocating the
1877  * context, may be NULL
1878  * @return >= 0 in case of success, a negative AVERROR code in case of
1879  * failure
1880  */
1882  const char *format_name, const char *filename);
1883 
1884 /**
1885  * @addtogroup lavf_decoding
1886  * @{
1887  */
1888 
1889 /**
1890  * Find AVInputFormat based on the short name of the input format.
1891  */
1892 const AVInputFormat *av_find_input_format(const char *short_name);
1893 
1894 /**
1895  * Guess the file format.
1896  *
1897  * @param pd data to be probed
1898  * @param is_opened Whether the file is already opened; determines whether
1899  * demuxers with or without AVFMT_NOFILE are probed.
1900  */
1901 const AVInputFormat *av_probe_input_format(const AVProbeData *pd, int is_opened);
1902 
1903 /**
1904  * Guess the file format.
1905  *
1906  * @param pd data to be probed
1907  * @param is_opened Whether the file is already opened; determines whether
1908  * demuxers with or without AVFMT_NOFILE are probed.
1909  * @param score_max A probe score larger that this is required to accept a
1910  * detection, the variable is set to the actual detection
1911  * score afterwards.
1912  * If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
1913  * to retry with a larger probe buffer.
1914  */
1916  int is_opened, int *score_max);
1917 
1918 /**
1919  * Guess the file format.
1920  *
1921  * @param is_opened Whether the file is already opened; determines whether
1922  * demuxers with or without AVFMT_NOFILE are probed.
1923  * @param score_ret The score of the best detection.
1924  */
1926  int is_opened, int *score_ret);
1927 
1928 /**
1929  * Probe a bytestream to determine the input format. Each time a probe returns
1930  * with a score that is too low, the probe buffer size is increased and another
1931  * attempt is made. When the maximum probe size is reached, the input format
1932  * with the highest score is returned.
1933  *
1934  * @param pb the bytestream to probe
1935  * @param fmt the input format is put here
1936  * @param url the url of the stream
1937  * @param logctx the log context
1938  * @param offset the offset within the bytestream to probe from
1939  * @param max_probe_size the maximum probe buffer size (zero for default)
1940  * @return the score in case of success, a negative value corresponding to an
1941  * the maximal score is AVPROBE_SCORE_MAX
1942  * AVERROR code otherwise
1943  */
1945  const char *url, void *logctx,
1946  unsigned int offset, unsigned int max_probe_size);
1947 
1948 /**
1949  * Like av_probe_input_buffer2() but returns 0 on success
1950  */
1952  const char *url, void *logctx,
1953  unsigned int offset, unsigned int max_probe_size);
1954 
1955 /**
1956  * Open an input stream and read the header. The codecs are not opened.
1957  * The stream must be closed with avformat_close_input().
1958  *
1959  * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
1960  * May be a pointer to NULL, in which case an AVFormatContext is allocated by this
1961  * function and written into ps.
1962  * Note that a user-supplied AVFormatContext will be freed on failure.
1963  * @param url URL of the stream to open.
1964  * @param fmt If non-NULL, this parameter forces a specific input format.
1965  * Otherwise the format is autodetected.
1966  * @param options A dictionary filled with AVFormatContext and demuxer-private options.
1967  * On return this parameter will be destroyed and replaced with a dict containing
1968  * options that were not found. May be NULL.
1969  *
1970  * @return 0 on success, a negative AVERROR on failure.
1971  *
1972  * @note If you want to use custom IO, preallocate the format context and set its pb field.
1973  */
1974 int avformat_open_input(AVFormatContext **ps, const char *url,
1975  const AVInputFormat *fmt, AVDictionary **options);
1976 
1977 /**
1978  * Read packets of a media file to get stream information. This
1979  * is useful for file formats with no headers such as MPEG. This
1980  * function also computes the real framerate in case of MPEG-2 repeat
1981  * frame mode.
1982  * The logical file position is not changed by this function;
1983  * examined packets may be buffered for later processing.
1984  *
1985  * @param ic media file handle
1986  * @param options If non-NULL, an ic.nb_streams long array of pointers to
1987  * dictionaries, where i-th member contains options for
1988  * codec corresponding to i-th stream.
1989  * On return each dictionary will be filled with options that were not found.
1990  * @return >=0 if OK, AVERROR_xxx on error
1991  *
1992  * @note this function isn't guaranteed to open all the codecs, so
1993  * options being non-empty at return is a perfectly normal behavior.
1994  *
1995  * @todo Let the user decide somehow what information is needed so that
1996  * we do not waste time getting stuff the user does not need.
1997  */
1999 
2000 /**
2001  * Find the programs which belong to a given stream.
2002  *
2003  * @param ic media file handle
2004  * @param last the last found program, the search will start after this
2005  * program, or from the beginning if it is NULL
2006  * @param s stream index
2007  * @return the next program which belongs to s, NULL if no program is found or
2008  * the last program is not among the programs of ic.
2009  */
2011 
2012 void av_program_add_stream_index(AVFormatContext *ac, int progid, unsigned int idx);
2013 
2014 /**
2015  * Find the "best" stream in the file.
2016  * The best stream is determined according to various heuristics as the most
2017  * likely to be what the user expects.
2018  * If the decoder parameter is non-NULL, av_find_best_stream will find the
2019  * default decoder for the stream's codec; streams for which no decoder can
2020  * be found are ignored.
2021  *
2022  * @param ic media file handle
2023  * @param type stream type: video, audio, subtitles, etc.
2024  * @param wanted_stream_nb user-requested stream number,
2025  * or -1 for automatic selection
2026  * @param related_stream try to find a stream related (eg. in the same
2027  * program) to this one, or -1 if none
2028  * @param decoder_ret if non-NULL, returns the decoder for the
2029  * selected stream
2030  * @param flags flags; none are currently defined
2031  * @return the non-negative stream number in case of success,
2032  * AVERROR_STREAM_NOT_FOUND if no stream with the requested type
2033  * could be found,
2034  * AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
2035  * @note If av_find_best_stream returns successfully and decoder_ret is not
2036  * NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
2037  */
2039  enum AVMediaType type,
2040  int wanted_stream_nb,
2041  int related_stream,
2042  const AVCodec **decoder_ret,
2043  int flags);
2044 
2045 /**
2046  * Return the next frame of a stream.
2047  * This function returns what is stored in the file, and does not validate
2048  * that what is there are valid frames for the decoder. It will split what is
2049  * stored in the file into frames and return one for each call. It will not
2050  * omit invalid data between valid frames so as to give the decoder the maximum
2051  * information possible for decoding.
2052  *
2053  * On success, the returned packet is reference-counted (pkt->buf is set) and
2054  * valid indefinitely. The packet must be freed with av_packet_unref() when
2055  * it is no longer needed. For video, the packet contains exactly one frame.
2056  * For audio, it contains an integer number of frames if each frame has
2057  * a known fixed size (e.g. PCM or ADPCM data). If the audio frames have
2058  * a variable size (e.g. MPEG audio), then it contains one frame.
2059  *
2060  * pkt->pts, pkt->dts and pkt->duration are always set to correct
2061  * values in AVStream.time_base units (and guessed if the format cannot
2062  * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
2063  * has B-frames, so it is better to rely on pkt->dts if you do not
2064  * decompress the payload.
2065  *
2066  * @return 0 if OK, < 0 on error or end of file. On error, pkt will be blank
2067  * (as if it came from av_packet_alloc()).
2068  *
2069  * @note pkt will be initialized, so it may be uninitialized, but it must not
2070  * contain data that needs to be freed.
2071  */
2073 
2074 /**
2075  * Seek to the keyframe at timestamp.
2076  * 'timestamp' in 'stream_index'.
2077  *
2078  * @param s media file handle
2079  * @param stream_index If stream_index is (-1), a default
2080  * stream is selected, and timestamp is automatically converted
2081  * from AV_TIME_BASE units to the stream specific time_base.
2082  * @param timestamp Timestamp in AVStream.time_base units
2083  * or, if no stream is specified, in AV_TIME_BASE units.
2084  * @param flags flags which select direction and seeking mode
2085  * @return >= 0 on success
2086  */
2087 int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
2088  int flags);
2089 
2090 /**
2091  * Seek to timestamp ts.
2092  * Seeking will be done so that the point from which all active streams
2093  * can be presented successfully will be closest to ts and within min/max_ts.
2094  * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
2095  *
2096  * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
2097  * are the file position (this may not be supported by all demuxers).
2098  * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
2099  * in the stream with stream_index (this may not be supported by all demuxers).
2100  * Otherwise all timestamps are in units of the stream selected by stream_index
2101  * or if stream_index is -1, in AV_TIME_BASE units.
2102  * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
2103  * keyframes (this may not be supported by all demuxers).
2104  * If flags contain AVSEEK_FLAG_BACKWARD, it is ignored.
2105  *
2106  * @param s media file handle
2107  * @param stream_index index of the stream which is used as time base reference
2108  * @param min_ts smallest acceptable timestamp
2109  * @param ts target timestamp
2110  * @param max_ts largest acceptable timestamp
2111  * @param flags flags
2112  * @return >=0 on success, error code otherwise
2113  *
2114  * @note This is part of the new seek API which is still under construction.
2115  */
2116 int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
2117 
2118 /**
2119  * Discard all internally buffered data. This can be useful when dealing with
2120  * discontinuities in the byte stream. Generally works only with formats that
2121  * can resync. This includes headerless formats like MPEG-TS/TS but should also
2122  * work with NUT, Ogg and in a limited way AVI for example.
2123  *
2124  * The set of streams, the detected duration, stream parameters and codecs do
2125  * not change when calling this function. If you want a complete reset, it's
2126  * better to open a new AVFormatContext.
2127  *
2128  * This does not flush the AVIOContext (s->pb). If necessary, call
2129  * avio_flush(s->pb) before calling this function.
2130  *
2131  * @param s media file handle
2132  * @return >=0 on success, error code otherwise
2133  */
2135 
2136 /**
2137  * Start playing a network-based stream (e.g. RTSP stream) at the
2138  * current position.
2139  */
2141 
2142 /**
2143  * Pause a network-based stream (e.g. RTSP stream).
2144  *
2145  * Use av_read_play() to resume it.
2146  */
2148 
2149 /**
2150  * Close an opened input AVFormatContext. Free it and all its contents
2151  * and set *s to NULL.
2152  */
2154 /**
2155  * @}
2156  */
2158 #define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
2159 #define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
2160 #define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
2161 #define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
2162 
2163 /**
2164  * @addtogroup lavf_encoding
2165  * @{
2166  */
2168 #define AVSTREAM_INIT_IN_WRITE_HEADER 0 ///< stream parameters initialized in avformat_write_header
2169 #define AVSTREAM_INIT_IN_INIT_OUTPUT 1 ///< stream parameters initialized in avformat_init_output
2170 
2171 /**
2172  * Allocate the stream private data and write the stream header to
2173  * an output media file.
2174  *
2175  * @param s Media file handle, must be allocated with avformat_alloc_context().
2176  * Its oformat field must be set to the desired output format;
2177  * Its pb field must be set to an already opened AVIOContext.
2178  * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
2179  * On return this parameter will be destroyed and replaced with a dict containing
2180  * options that were not found. May be NULL.
2181  *
2182  * @return AVSTREAM_INIT_IN_WRITE_HEADER on success if the codec had not already been fully initialized in avformat_init,
2183  * AVSTREAM_INIT_IN_INIT_OUTPUT on success if the codec had already been fully initialized in avformat_init,
2184  * negative AVERROR on failure.
2185  *
2186  * @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_init_output.
2187  */
2190 
2191 /**
2192  * Allocate the stream private data and initialize the codec, but do not write the header.
2193  * May optionally be used before avformat_write_header to initialize stream parameters
2194  * before actually writing the header.
2195  * If using this function, do not pass the same options to avformat_write_header.
2196  *
2197  * @param s Media file handle, must be allocated with avformat_alloc_context().
2198  * Its oformat field must be set to the desired output format;
2199  * Its pb field must be set to an already opened AVIOContext.
2200  * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
2201  * On return this parameter will be destroyed and replaced with a dict containing
2202  * options that were not found. May be NULL.
2203  *
2204  * @return AVSTREAM_INIT_IN_WRITE_HEADER on success if the codec requires avformat_write_header to fully initialize,
2205  * AVSTREAM_INIT_IN_INIT_OUTPUT on success if the codec has been fully initialized,
2206  * negative AVERROR on failure.
2207  *
2208  * @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_write_header.
2209  */
2212 
2213 /**
2214  * Write a packet to an output media file.
2215  *
2216  * This function passes the packet directly to the muxer, without any buffering
2217  * or reordering. The caller is responsible for correctly interleaving the
2218  * packets if the format requires it. Callers that want libavformat to handle
2219  * the interleaving should call av_interleaved_write_frame() instead of this
2220  * function.
2221  *
2222  * @param s media file handle
2223  * @param pkt The packet containing the data to be written. Note that unlike
2224  * av_interleaved_write_frame(), this function does not take
2225  * ownership of the packet passed to it (though some muxers may make
2226  * an internal reference to the input packet).
2227  * <br>
2228  * This parameter can be NULL (at any time, not just at the end), in
2229  * order to immediately flush data buffered within the muxer, for
2230  * muxers that buffer up data internally before writing it to the
2231  * output.
2232  * <br>
2233  * Packet's @ref AVPacket.stream_index "stream_index" field must be
2234  * set to the index of the corresponding stream in @ref
2235  * AVFormatContext.streams "s->streams".
2236  * <br>
2237  * The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2238  * must be set to correct values in the stream's timebase (unless the
2239  * output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2240  * they can be set to AV_NOPTS_VALUE).
2241  * The dts for subsequent packets passed to this function must be strictly
2242  * increasing when compared in their respective timebases (unless the
2243  * output format is flagged with the AVFMT_TS_NONSTRICT, then they
2244  * merely have to be nondecreasing). @ref AVPacket.duration
2245  * "duration") should also be set if known.
2246  * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
2247  *
2248  * @see av_interleaved_write_frame()
2249  */
2251 
2252 /**
2253  * Write a packet to an output media file ensuring correct interleaving.
2254  *
2255  * This function will buffer the packets internally as needed to make sure the
2256  * packets in the output file are properly interleaved in the order of
2257  * increasing dts. Callers doing their own interleaving should call
2258  * av_write_frame() instead of this function.
2259  *
2260  * Using this function instead of av_write_frame() can give muxers advance
2261  * knowledge of future packets, improving e.g. the behaviour of the mp4
2262  * muxer for VFR content in fragmenting mode.
2263  *
2264  * @param s media file handle
2265  * @param pkt The packet containing the data to be written.
2266  * <br>
2267  * If the packet is reference-counted, this function will take
2268  * ownership of this reference and unreference it later when it sees
2269  * fit.
2270  * The caller must not access the data through this reference after
2271  * this function returns. If the packet is not reference-counted,
2272  * libavformat will make a copy.
2273  * <br>
2274  * This parameter can be NULL (at any time, not just at the end), to
2275  * flush the interleaving queues.
2276  * <br>
2277  * Packet's @ref AVPacket.stream_index "stream_index" field must be
2278  * set to the index of the corresponding stream in @ref
2279  * AVFormatContext.streams "s->streams".
2280  * <br>
2281  * The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2282  * must be set to correct values in the stream's timebase (unless the
2283  * output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2284  * they can be set to AV_NOPTS_VALUE).
2285  * The dts for subsequent packets in one stream must be strictly
2286  * increasing (unless the output format is flagged with the
2287  * AVFMT_TS_NONSTRICT, then they merely have to be nondecreasing).
2288  * @ref AVPacket.duration "duration") should also be set if known.
2289  *
2290  * @return 0 on success, a negative AVERROR on error. Libavformat will always
2291  * take care of freeing the packet, even if this function fails.
2292  *
2293  * @see av_write_frame(), AVFormatContext.max_interleave_delta
2294  */
2296 
2297 /**
2298  * Write an uncoded frame to an output media file.
2299  *
2300  * The frame must be correctly interleaved according to the container
2301  * specification; if not, av_interleaved_write_uncoded_frame() must be used.
2302  *
2303  * See av_interleaved_write_uncoded_frame() for details.
2304  */
2305 int av_write_uncoded_frame(AVFormatContext *s, int stream_index,
2306  AVFrame *frame);
2307 
2308 /**
2309  * Write an uncoded frame to an output media file.
2310  *
2311  * If the muxer supports it, this function makes it possible to write an AVFrame
2312  * structure directly, without encoding it into a packet.
2313  * It is mostly useful for devices and similar special muxers that use raw
2314  * video or PCM data and will not serialize it into a byte stream.
2315  *
2316  * To test whether it is possible to use it with a given muxer and stream,
2317  * use av_write_uncoded_frame_query().
2318  *
2319  * The caller gives up ownership of the frame and must not access it
2320  * afterwards.
2321  *
2322  * @return >=0 for success, a negative code on error
2323  */
2325  AVFrame *frame);
2326 
2327 /**
2328  * Test whether a muxer supports uncoded frame.
2329  *
2330  * @return >=0 if an uncoded frame can be written to that muxer and stream,
2331  * <0 if not
2332  */
2333 int av_write_uncoded_frame_query(AVFormatContext *s, int stream_index);
2334 
2335 /**
2336  * Write the stream trailer to an output media file and free the
2337  * file private data.
2338  *
2339  * May only be called after a successful call to avformat_write_header.
2340  *
2341  * @param s media file handle
2342  * @return 0 if OK, AVERROR_xxx on error
2343  */
2345 
2346 /**
2347  * Return the output format in the list of registered output formats
2348  * which best matches the provided parameters, or return NULL if
2349  * there is no match.
2350  *
2351  * @param short_name if non-NULL checks if short_name matches with the
2352  * names of the registered formats
2353  * @param filename if non-NULL checks if filename terminates with the
2354  * extensions of the registered formats
2355  * @param mime_type if non-NULL checks if mime_type matches with the
2356  * MIME type of the registered formats
2357  */
2358 const AVOutputFormat *av_guess_format(const char *short_name,
2359  const char *filename,
2360  const char *mime_type);
2361 
2362 /**
2363  * Guess the codec ID based upon muxer and filename.
2364  */
2365 enum AVCodecID av_guess_codec(const AVOutputFormat *fmt, const char *short_name,
2366  const char *filename, const char *mime_type,
2367  enum AVMediaType type);
2368 
2369 /**
2370  * Get timing information for the data currently output.
2371  * The exact meaning of "currently output" depends on the format.
2372  * It is mostly relevant for devices that have an internal buffer and/or
2373  * work in real time.
2374  * @param s media file handle
2375  * @param stream stream in the media file
2376  * @param[out] dts DTS of the last packet output for the stream, in stream
2377  * time_base units
2378  * @param[out] wall absolute time when that packet whas output,
2379  * in microsecond
2380  * @return 0 if OK, AVERROR(ENOSYS) if the format does not support it
2381  * Note: some formats or devices may not allow to measure dts and wall
2382  * atomically.
2383  */
2384 int av_get_output_timestamp(struct AVFormatContext *s, int stream,
2385  int64_t *dts, int64_t *wall);
2386 
2387 
2388 /**
2389  * @}
2390  */
2391 
2392 
2393 /**
2394  * @defgroup lavf_misc Utility functions
2395  * @ingroup libavf
2396  * @{
2397  *
2398  * Miscellaneous utility functions related to both muxing and demuxing
2399  * (or neither).
2400  */
2401 
2402 /**
2403  * Send a nice hexadecimal dump of a buffer to the specified file stream.
2404  *
2405  * @param f The file stream pointer where the dump should be sent to.
2406  * @param buf buffer
2407  * @param size buffer size
2408  *
2409  * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
2410  */
2411 void av_hex_dump(FILE *f, const uint8_t *buf, int size);
2412 
2413 /**
2414  * Send a nice hexadecimal dump of a buffer to the log.
2415  *
2416  * @param avcl A pointer to an arbitrary struct of which the first field is a
2417  * pointer to an AVClass struct.
2418  * @param level The importance level of the message, lower values signifying
2419  * higher importance.
2420  * @param buf buffer
2421  * @param size buffer size
2422  *
2423  * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
2424  */
2425 void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
2426 
2427 /**
2428  * Send a nice dump of a packet to the specified file stream.
2429  *
2430  * @param f The file stream pointer where the dump should be sent to.
2431  * @param pkt packet to dump
2432  * @param dump_payload True if the payload must be displayed, too.
2433  * @param st AVStream that the packet belongs to
2434  */
2435 void av_pkt_dump2(FILE *f, const AVPacket *pkt, int dump_payload, const AVStream *st);
2436 
2437 
2438 /**
2439  * Send a nice dump of a packet to the log.
2440  *
2441  * @param avcl A pointer to an arbitrary struct of which the first field is a
2442  * pointer to an AVClass struct.
2443  * @param level The importance level of the message, lower values signifying
2444  * higher importance.
2445  * @param pkt packet to dump
2446  * @param dump_payload True if the payload must be displayed, too.
2447  * @param st AVStream that the packet belongs to
2448  */
2449 void av_pkt_dump_log2(void *avcl, int level, const AVPacket *pkt, int dump_payload,
2450  const AVStream *st);
2451 
2452 /**
2453  * Get the AVCodecID for the given codec tag tag.
2454  * If no codec id is found returns AV_CODEC_ID_NONE.
2455  *
2456  * @param tags list of supported codec_id-codec_tag pairs, as stored
2457  * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2458  * @param tag codec tag to match to a codec ID
2459  */
2460 enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
2461 
2462 /**
2463  * Get the codec tag for the given codec id id.
2464  * If no codec tag is found returns 0.
2465  *
2466  * @param tags list of supported codec_id-codec_tag pairs, as stored
2467  * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2468  * @param id codec ID to match to a codec tag
2469  */
2470 unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id);
2471 
2472 /**
2473  * Get the codec tag for the given codec id.
2474  *
2475  * @param tags list of supported codec_id - codec_tag pairs, as stored
2476  * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2477  * @param id codec id that should be searched for in the list
2478  * @param tag A pointer to the found tag
2479  * @return 0 if id was not found in tags, > 0 if it was found
2480  */
2481 int av_codec_get_tag2(const struct AVCodecTag * const *tags, enum AVCodecID id,
2482  unsigned int *tag);
2483 
2485 
2486 /**
2487  * Get the index for a specific timestamp.
2488  *
2489  * @param st stream that the timestamp belongs to
2490  * @param timestamp timestamp to retrieve the index for
2491  * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
2492  * to the timestamp which is <= the requested one, if backward
2493  * is 0, then it will be >=
2494  * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
2495  * @return < 0 if no such timestamp could be found
2496  */
2497 int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
2498 
2499 /**
2500  * Get the index entry count for the given AVStream.
2501  *
2502  * @param st stream
2503  * @return the number of index entries in the stream
2504  */
2506 
2507 /**
2508  * Get the AVIndexEntry corresponding to the given index.
2509  *
2510  * @param st Stream containing the requested AVIndexEntry.
2511  * @param idx The desired index.
2512  * @return A pointer to the requested AVIndexEntry if it exists, NULL otherwise.
2513  *
2514  * @note The pointer returned by this function is only guaranteed to be valid
2515  * until any function that takes the stream or the parent AVFormatContext
2516  * as input argument is called.
2517  */
2518 const AVIndexEntry *avformat_index_get_entry(AVStream *st, int idx);
2519 
2520 /**
2521  * Get the AVIndexEntry corresponding to the given timestamp.
2522  *
2523  * @param st Stream containing the requested AVIndexEntry.
2524  * @param timestamp Timestamp to retrieve the index entry for.
2525  * @param flags If AVSEEK_FLAG_BACKWARD then the returned entry will correspond
2526  * to the timestamp which is <= the requested one, if backward
2527  * is 0, then it will be >=
2528  * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise.
2529  * @return A pointer to the requested AVIndexEntry if it exists, NULL otherwise.
2530  *
2531  * @note The pointer returned by this function is only guaranteed to be valid
2532  * until any function that takes the stream or the parent AVFormatContext
2533  * as input argument is called.
2534  */
2536  int64_t wanted_timestamp,
2537  int flags);
2538 /**
2539  * Add an index entry into a sorted list. Update the entry if the list
2540  * already contains it.
2541  *
2542  * @param timestamp timestamp in the time base of the given stream
2543  */
2544 int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
2545  int size, int distance, int flags);
2546 
2547 
2548 /**
2549  * Split a URL string into components.
2550  *
2551  * The pointers to buffers for storing individual components may be null,
2552  * in order to ignore that component. Buffers for components not found are
2553  * set to empty strings. If the port is not found, it is set to a negative
2554  * value.
2555  *
2556  * @param proto the buffer for the protocol
2557  * @param proto_size the size of the proto buffer
2558  * @param authorization the buffer for the authorization
2559  * @param authorization_size the size of the authorization buffer
2560  * @param hostname the buffer for the host name
2561  * @param hostname_size the size of the hostname buffer
2562  * @param port_ptr a pointer to store the port number in
2563  * @param path the buffer for the path
2564  * @param path_size the size of the path buffer
2565  * @param url the URL to split
2566  */
2567 void av_url_split(char *proto, int proto_size,
2568  char *authorization, int authorization_size,
2569  char *hostname, int hostname_size,
2570  int *port_ptr,
2571  char *path, int path_size,
2572  const char *url);
2573 
2574 
2575 /**
2576  * Print detailed information about the input or output format, such as
2577  * duration, bitrate, streams, container, programs, metadata, side data,
2578  * codec and time base.
2579  *
2580  * @param ic the context to analyze
2581  * @param index index of the stream to dump information about
2582  * @param url the URL to print, such as source or destination file
2583  * @param is_output Select whether the specified context is an input(0) or output(1)
2584  */
2586  int index,
2587  const char *url,
2588  int is_output);
2590 
2591 #define AV_FRAME_FILENAME_FLAGS_MULTIPLE 1 ///< Allow multiple %d
2592 
2593 /**
2594  * Return in 'buf' the path with '%d' replaced by a number.
2595  *
2596  * Also handles the '%0nd' format where 'n' is the total number
2597  * of digits and '%%'.
2598  *
2599  * @param buf destination buffer
2600  * @param buf_size destination buffer size
2601  * @param path numbered sequence string
2602  * @param number frame number
2603  * @param flags AV_FRAME_FILENAME_FLAGS_*
2604  * @return 0 if OK, -1 on format error
2605  */
2606 int av_get_frame_filename2(char *buf, int buf_size,
2607  const char *path, int number, int flags);
2608 
2609 int av_get_frame_filename(char *buf, int buf_size,
2610  const char *path, int number);
2611 
2612 /**
2613  * Check whether filename actually is a numbered sequence generator.
2614  *
2615  * @param filename possible numbered sequence string
2616  * @return 1 if a valid numbered sequence string, 0 otherwise
2617  */
2618 int av_filename_number_test(const char *filename);
2619 
2620 /**
2621  * Generate an SDP for an RTP session.
2622  *
2623  * Note, this overwrites the id values of AVStreams in the muxer contexts
2624  * for getting unique dynamic payload types.
2625  *
2626  * @param ac array of AVFormatContexts describing the RTP streams. If the
2627  * array is composed by only one context, such context can contain
2628  * multiple AVStreams (one AVStream per RTP stream). Otherwise,
2629  * all the contexts in the array (an AVCodecContext per RTP stream)
2630  * must contain only one AVStream.
2631  * @param n_files number of AVCodecContexts contained in ac
2632  * @param buf buffer where the SDP will be stored (must be allocated by
2633  * the caller)
2634  * @param size the size of the buffer
2635  * @return 0 if OK, AVERROR_xxx on error
2636  */
2637 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
2638 
2639 /**
2640  * Return a positive value if the given filename has one of the given
2641  * extensions, 0 otherwise.
2642  *
2643  * @param filename file name to check against the given extensions
2644  * @param extensions a comma-separated list of filename extensions
2645  */
2646 int av_match_ext(const char *filename, const char *extensions);
2647 
2648 /**
2649  * Test if the given container can store a codec.
2650  *
2651  * @param ofmt container to check for compatibility
2652  * @param codec_id codec to potentially store in container
2653  * @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
2654  *
2655  * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
2656  * A negative number if this information is not available.
2657  */
2659  int std_compliance);
2660 
2661 /**
2662  * @defgroup riff_fourcc RIFF FourCCs
2663  * @{
2664  * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
2665  * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
2666  * following code:
2667  * @code
2668  * uint32_t tag = MKTAG('H', '2', '6', '4');
2669  * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
2670  * enum AVCodecID id = av_codec_get_id(table, tag);
2671  * @endcode
2672  */
2673 /**
2674  * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
2675  */
2676 const struct AVCodecTag *avformat_get_riff_video_tags(void);
2677 /**
2678  * @return the table mapping RIFF FourCCs for audio to AVCodecID.
2679  */
2680 const struct AVCodecTag *avformat_get_riff_audio_tags(void);
2681 /**
2682  * @return the table mapping MOV FourCCs for video to libavcodec AVCodecID.
2683  */
2684 const struct AVCodecTag *avformat_get_mov_video_tags(void);
2685 /**
2686  * @return the table mapping MOV FourCCs for audio to AVCodecID.
2687  */
2688 const struct AVCodecTag *avformat_get_mov_audio_tags(void);
2689 
2690 /**
2691  * @}
2692  */
2693 
2694 /**
2695  * Guess the sample aspect ratio of a frame, based on both the stream and the
2696  * frame aspect ratio.
2697  *
2698  * Since the frame aspect ratio is set by the codec but the stream aspect ratio
2699  * is set by the demuxer, these two may not be equal. This function tries to
2700  * return the value that you should use if you would like to display the frame.
2701  *
2702  * Basic logic is to use the stream aspect ratio if it is set to something sane
2703  * otherwise use the frame aspect ratio. This way a container setting, which is
2704  * usually easy to modify can override the coded value in the frames.
2705  *
2706  * @param format the format context which the stream is part of
2707  * @param stream the stream which the frame is part of
2708  * @param frame the frame with the aspect ratio to be determined
2709  * @return the guessed (valid) sample_aspect_ratio, 0/1 if no idea
2710  */
2712 
2713 /**
2714  * Guess the frame rate, based on both the container and codec information.
2715  *
2716  * @param ctx the format context which the stream is part of
2717  * @param stream the stream which the frame is part of
2718  * @param frame the frame for which the frame rate should be determined, may be NULL
2719  * @return the guessed (valid) frame rate, 0/1 if no idea
2720  */
2722 
2723 /**
2724  * Check if the stream st contained in s is matched by the stream specifier
2725  * spec.
2726  *
2727  * See the "stream specifiers" chapter in the documentation for the syntax
2728  * of spec.
2729  *
2730  * @return >0 if st is matched by spec;
2731  * 0 if st is not matched by spec;
2732  * AVERROR code if spec is invalid
2733  *
2734  * @note A stream specifier can match several streams in the format.
2735  */
2737  const char *spec);
2738 
2745 #if FF_API_R_FRAME_RATE
2746  AVFMT_TBCF_R_FRAMERATE,
2747 #endif
2748 };
2749 
2750 /**
2751  * Transfer internal timing information from one stream to another.
2752  *
2753  * This function is useful when doing stream copy.
2754  *
2755  * @param ofmt target output format for ost
2756  * @param ost output stream which needs timings copy and adjustments
2757  * @param ist reference input stream to copy timings from
2758  * @param copy_tb define from where the stream codec timebase needs to be imported
2759  */
2761  AVStream *ost, const AVStream *ist,
2762  enum AVTimebaseSource copy_tb);
2763 
2764 /**
2765  * Get the internal codec timebase from a stream.
2766  *
2767  * @param st input stream to extract the timebase from
2768  */
2770 
2771 /**
2772  * @}
2773  */
2774 
2775 #endif /* AVFORMAT_AVFORMAT_H */
avformat_get_riff_video_tags
const struct AVCodecTag * avformat_get_riff_video_tags(void)
Definition: riff.c:620
AVFormatContext::control_message_cb
av_format_control_message control_message_cb
Callback used by devices to communicate with application.
Definition: avformat.h:1612
av_pkt_dump2
void av_pkt_dump2(FILE *f, const AVPacket *pkt, int dump_payload, const AVStream *st)
Send a nice dump of a packet to the specified file stream.
Definition: dump.c:111
AVCodec
AVCodec.
Definition: codec.h:197
av_codec_get_id
enum AVCodecID av_codec_get_id(const struct AVCodecTag *const *tags, unsigned int tag)
Get the AVCodecID for the given codec tag tag.
av_format_control_message
int(* av_format_control_message)(struct AVFormatContext *s, int type, void *data, size_t data_size)
Callback used by devices to communicate with application.
Definition: avformat.h:1074
level
uint8_t level
Definition: svq3.c:204
av_fmt_ctx_get_duration_estimation_method
enum AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext *ctx)
Returns the method used to set ctx->duration.
Definition: options.c:196
AVFMT_DURATION_FROM_BITRATE
@ AVFMT_DURATION_FROM_BITRATE
Duration estimated from bitrate (less accurate)
Definition: avformat.h:1087
AVOutputFormat::extensions
const char * extensions
comma-separated filename extensions
Definition: avformat.h:499
AVOutputFormat::name
const char * name
Definition: avformat.h:491
AVChapter::metadata
AVDictionary * metadata
Definition: avformat.h:1067
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4374
av_probe_input_buffer2
int av_probe_input_buffer2(AVIOContext *pb, const AVInputFormat **fmt, const char *url, void *logctx, unsigned int offset, unsigned int max_probe_size)
Probe a bytestream to determine the input format.
Definition: format.c:223
AVInputFormat::raw_codec_id
int raw_codec_id
Raw demuxers store their codec ID here.
Definition: avformat.h:665
AVProgram::nb_stream_indexes
unsigned int nb_stream_indexes
Definition: avformat.h:1033
AVFormatContext::max_chunk_duration
int max_chunk_duration
Max chunk time in microseconds.
Definition: avformat.h:1457
out
FILE * out
Definition: movenc.c:54
AVFormatContext::max_index_size
unsigned int max_index_size
Maximum amount of memory in bytes to use for the index of each stream.
Definition: avformat.h:1299
AVFormatContext::nb_chapters
unsigned int nb_chapters
Number of chapters in AVChapter array.
Definition: avformat.h:1318
AVCodecParameters
This struct describes the properties of an encoded stream.
Definition: codec_par.h:52
AVStream::priv_data
void * priv_data
Definition: avformat.h:841
AVStream::discard
enum AVDiscard discard
Selects which packets can be discarded at will and do not need to be demuxed.
Definition: avformat.h:881
av_find_program_from_stream
AVProgram * av_find_program_from_stream(AVFormatContext *ic, AVProgram *last, int s)
Find the programs which belong to a given stream.
Definition: utils.c:4101
AVFormatContext::audio_preload
int audio_preload
Audio preload in microseconds.
Definition: avformat.h:1449
AVFormatContext::protocol_blacklist
char * protocol_blacklist
',' separated list of disallowed protocols.
Definition: avformat.h:1674
AVDeviceCapabilitiesQuery
Following API allows user to probe device capabilities (supported codecs, pixel formats,...
Definition: avdevice.h:401
AVFMT_TBCF_DECODER
@ AVFMT_TBCF_DECODER
Definition: avformat.h:2741
AVProgram::pmt_version
int pmt_version
Definition: avformat.h:1039
avformat_get_class
const AVClass * avformat_get_class(void)
Get the AVClass for AVFormatContext.
Definition: options.c:201
AVFMT_TBCF_AUTO
@ AVFMT_TBCF_AUTO
Definition: avformat.h:2740
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
AVFormatContext::streams
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1174
index
fg index
Definition: ffmpeg_filter.c:168
AVPacketSideData
Definition: packet.h:306
AVFormatContext::strict_std_compliance
int strict_std_compliance
Allow non-standard and experimental extension.
Definition: avformat.h:1397
av_write_uncoded_frame
int av_write_uncoded_frame(AVFormatContext *s, int stream_index, AVFrame *frame)
Write an uncoded frame to an output media file.
Definition: mux.c:1360
av_get_frame_filename2
int av_get_frame_filename2(char *buf, int buf_size, const char *path, int number, int flags)
Return in 'buf' the path with 'd' replaced by a number.
Definition: utils.c:4590
AVFormatContext::max_interleave_delta
int64_t max_interleave_delta
Maximum buffering duration for interleaving.
Definition: avformat.h:1391
AVStream::avg_frame_rate
AVRational avg_frame_rate
Average framerate.
Definition: avformat.h:899
AVChapter::start
int64_t start
Definition: avformat.h:1066
data
const char data[16]
Definition: mxf.c:142
AVFormatContext::duration_estimation_method
enum AVDurationEstimationMethod duration_estimation_method
The duration field can be estimated through various ways, and this field can be used to know how the ...
Definition: avformat.h:1488
AVStream::cur_dts
int64_t cur_dts
Definition: avformat.h:1002
AVOutputFormat::check_bitstream
int(* check_bitstream)(struct AVFormatContext *, const AVPacket *pkt)
Set up any necessary bitstream filtering and extract any extra data needed for the global header.
Definition: avformat.h:606
AVFMT_TBCF_DEMUXER
@ AVFMT_TBCF_DEMUXER
Definition: avformat.h:2742
AVOutputFormat::deinit
void(* deinit)(struct AVFormatContext *)
Deinitialize format.
Definition: avformat.h:600
AVFormatContext::programs
AVProgram ** programs
Definition: avformat.h:1269
AVOutputFormat::write_packet
int(* write_packet)(struct AVFormatContext *, AVPacket *pkt)
Write a packet.
Definition: avformat.h:541
AVDictionary
Definition: dict.c:30
AVProgram::flags
int flags
Definition: avformat.h:1030
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:444
AVFormatContext::probesize
int64_t probesize
Maximum size of the data read from input for determining the input container format.
Definition: avformat.h:1255
av_write_uncoded_frame_query
int av_write_uncoded_frame_query(AVFormatContext *s, int stream_index)
Test whether a muxer supports uncoded frame.
Definition: mux.c:1372
avformat_init_output
av_warn_unused_result int avformat_init_output(AVFormatContext *s, AVDictionary **options)
Allocate the stream private data and initialize the codec, but do not write the header.
Definition: mux.c:448
av_read_frame
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
Definition: utils.c:1665
AVFormatContext::video_codec_id
enum AVCodecID video_codec_id
Forced video codec_id.
Definition: avformat.h:1275
AVOutputFormat::write_trailer
int(* write_trailer)(struct AVFormatContext *)
Definition: avformat.h:542
avformat_index_get_entry_from_timestamp
const AVIndexEntry * avformat_index_get_entry_from_timestamp(AVStream *st, int64_t wanted_timestamp, int flags)
Get the AVIndexEntry corresponding to the given timestamp.
Definition: utils.c:2073
av_get_frame_filename
int av_get_frame_filename(char *buf, int buf_size, const char *path, int number)
Definition: utils.c:4648
AVIndexEntry
Definition: avformat.h:762
AVOutputFormat::subtitle_codec
enum AVCodecID subtitle_codec
default subtitle codec
Definition: avformat.h:503
AVIOInterruptCB
Callback for checking whether to abort blocking functions.
Definition: avio.h:58
AVProgram::pmt_pid
int pmt_pid
Definition: avformat.h:1037
AVInputFormat::long_name
const char * long_name
Descriptive name for the format, meant to be more human-readable than name.
Definition: avformat.h:628
av_filename_number_test
int av_filename_number_test(const char *filename)
Check whether filename actually is a numbered sequence generator.
Definition: utils.c:303
av_find_best_stream
int av_find_best_stream(AVFormatContext *ic, enum AVMediaType type, int wanted_stream_nb, int related_stream, const AVCodec **decoder_ret, int flags)
Find the "best" stream in the file.
Definition: utils.c:4118
avformat_queue_attached_pictures
int avformat_queue_attached_pictures(AVFormatContext *s)
Definition: utils.c:397
avformat_close_input
void avformat_close_input(AVFormatContext **s)
Close an opened input AVFormatContext.
Definition: utils.c:4346
AVFormatContext::interrupt_callback
AVIOInterruptCB interrupt_callback
Custom interrupt callbacks for the I/O layer.
Definition: avformat.h:1367
AVFormatInternal
Definition: internal.h:64
AVFormatContext::flush_packets
int flush_packets
Flush the I/O context after each packet.
Definition: avformat.h:1516
avformat_get_mov_video_tags
const struct AVCodecTag * avformat_get_mov_video_tags(void)
Definition: isom_tags.c:338
AVFormatContext::max_picture_buffer
unsigned int max_picture_buffer
Maximum amount of memory in bytes to use for buffering frames obtained from realtime capture devices.
Definition: avformat.h:1305
av_add_index_entry
int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp, int size, int distance, int flags)
Add an index entry into a sorted list.
Definition: utils.c:1937
AVSTREAM_PARSE_FULL_ONCE
@ AVSTREAM_PARSE_FULL_ONCE
full parsing and repack of the first frame only, only implemented for H.264 currently
Definition: avformat.h:756
avformat_version
unsigned avformat_version(void)
Return the LIBAVFORMAT_VERSION_INT constant.
Definition: utils.c:62
AVStreamParseType
AVStreamParseType
Definition: avformat.h:751
AVProgram::discard
enum AVDiscard discard
selects which program to discard and which to feed to the caller
Definition: avformat.h:1031
AVChapter
Definition: avformat.h:1063
AVFormatContext::dump_separator
uint8_t * dump_separator
dump format separator.
Definition: avformat.h:1626
AVFMT_DURATION_FROM_PTS
@ AVFMT_DURATION_FROM_PTS
Duration accurately estimated from PTSes.
Definition: avformat.h:1085
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition: writing_filters.txt:86
ist
fg inputs[0] ist
Definition: ffmpeg_filter.c:182
av_new_program
AVProgram * av_new_program(AVFormatContext *s, int id)
Definition: utils.c:4456
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:875
av_codec_get_tag2
int av_codec_get_tag2(const struct AVCodecTag *const *tags, enum AVCodecID id, unsigned int *tag)
Get the codec tag for the given codec id.
av_probe_input_format3
const AVInputFormat * av_probe_input_format3(const AVProbeData *pd, int is_opened, int *score_ret)
Guess the file format.
Definition: format.c:128
avformat_network_init
int avformat_network_init(void)
Do global initialization of network libraries.
Definition: utils.c:4905
AVFormatContext::event_flags
int event_flags
Flags indicating events happening on the file, a combination of AVFMT_EVENT_FLAG_*.
Definition: avformat.h:1410
AVStream::attached_pic
AVPacket attached_pic
For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet will contain the attached pictu...
Definition: avformat.h:908
avformat_get_riff_audio_tags
const struct AVCodecTag * avformat_get_riff_audio_tags(void)
Definition: riff.c:625
AVFormatContext::bit_rate
int64_t bit_rate
Total stream bitrate in bit/s, 0 if not available.
Definition: avformat.h:1215
AVFormatContext::max_ts_probe
int max_ts_probe
Maximum number of packets to read while waiting for the first timestamp.
Definition: avformat.h:1423
AVFormatContext::format_whitelist
char * format_whitelist
',' separated list of allowed demuxers.
Definition: avformat.h:1548
AVFormatContext::format_probesize
int format_probesize
number of bytes to read maximally to identify format.
Definition: avformat.h:1532
av_guess_sample_aspect_ratio
AVRational av_guess_sample_aspect_ratio(AVFormatContext *format, AVStream *stream, AVFrame *frame)
Guess the sample aspect ratio of a frame, based on both the stream and the frame aspect ratio.
Definition: utils.c:4968
pkt
AVPacket * pkt
Definition: movenc.c:59
avformat_index_get_entries_count
int avformat_index_get_entries_count(const AVStream *st)
Get the index entry count for the given AVStream.
Definition: utils.c:2060
AVFormatContext::metadata
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1329
AVInputFormat
Definition: avformat.h:616
AVProbeData::mime_type
const char * mime_type
mime_type, when known.
Definition: avformat.h:445
AVInputFormat::extensions
const char * extensions
If extensions are defined, then no probe is done.
Definition: avformat.h:642
AVFormatContext::subtitle_codec
const AVCodec * subtitle_codec
Forced subtitle codec.
Definition: avformat.h:1586
av_dump_format
void av_dump_format(AVFormatContext *ic, int index, const char *url, int is_output)
Print detailed information about the input or output format, such as duration, bitrate,...
Definition: dump.c:620
AVCodecTag
Definition: internal.h:42
AVFormatContext::ctx_flags
int ctx_flags
Flags signalling stream properties.
Definition: avformat.h:1155
AVStream::first_dts
int64_t first_dts
Timestamp corresponding to the last dts sync point.
Definition: avformat.h:1001
AVOutputFormat::data_codec
enum AVCodecID data_codec
default data codec
Definition: avformat.h:581
AVProgram::id
int id
Definition: avformat.h:1029
avformat_open_input
int avformat_open_input(AVFormatContext **ps, const char *url, const AVInputFormat *fmt, AVDictionary **options)
Open an input stream and read the header.
Definition: utils.c:481
avformat_query_codec
int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id, int std_compliance)
Test if the given container can store a codec.
Definition: utils.c:4887
AVChapter::end
int64_t end
chapter start/end time in time_base units
Definition: avformat.h:1066
s
#define s(width, name)
Definition: cbs_vp9.c:257
av_seek_frame
int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Seek to the keyframe at timestamp.
Definition: utils.c:2440
AVFormatContext::flags
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1224
AVFormatContext::nb_programs
unsigned int nb_programs
Definition: avformat.h:1268
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:621
AVFormatContext::iformat
const struct AVInputFormat * iformat
The input container format.
Definition: avformat.h:1118
AVFormatContext::chapters
AVChapter ** chapters
Definition: avformat.h:1319
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
AVIndexEntry::size
int size
Definition: avformat.h:773
AVProbeData::filename
const char * filename
Definition: avformat.h:442
AVOpenCallback
int(* AVOpenCallback)(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options)
Definition: avformat.h:1077
av_match_ext
int av_match_ext(const char *filename, const char *extensions)
Return a positive value if the given filename has one of the given extensions, 0 otherwise.
Definition: format.c:38
AVIndexEntry::timestamp
int64_t timestamp
Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are...
Definition: avformat.h:764
AVOutputFormat::audio_codec
enum AVCodecID audio_codec
default audio codec
Definition: avformat.h:501
AVFormatContext::output_ts_offset
int64_t output_ts_offset
Output timestamp offset, in microseconds.
Definition: avformat.h:1618
AVInputFormat::mime_type
const char * mime_type
Comma-separated list of mime types.
Definition: avformat.h:653
av_read_play
int av_read_play(AVFormatContext *s)
Start playing a network-based stream (e.g.
Definition: utils.c:4186
ctx
AVFormatContext * ctx
Definition: movenc.c:48
avformat_flush
int avformat_flush(AVFormatContext *s)
Discard all internally buffered data.
Definition: utils.c:2520
AVOutputFormat::init
int(* init)(struct AVFormatContext *)
Initialize format.
Definition: avformat.h:591
AVOutputFormat::codec_tag
const struct AVCodecTag *const * codec_tag
List of supported codec_id-codec_tag pairs, ordered by "better choice first".
Definition: avformat.h:516
AVIndexEntry::min_distance
int min_distance
Minimum distance between this and the previous keyframe, used to avoid unneeded searching.
Definition: avformat.h:774
av_interleaved_write_uncoded_frame
int av_interleaved_write_uncoded_frame(AVFormatContext *s, int stream_index, AVFrame *frame)
Write an uncoded frame to an output media file.
Definition: mux.c:1366
codec_id
enum AVCodecID codec_id
Definition: vaapi_decode.c:369
AVProgram::start_time
int64_t start_time
Definition: avformat.h:1048
AVFormatContext::opaque
void * opaque
User data.
Definition: avformat.h:1607
AVFormatContext::probe_score
int probe_score
format probing score.
Definition: avformat.h:1525
f
#define f(width, name)
Definition: cbs_vp9.c:255
AVOutputFormat::get_output_timestamp
void(* get_output_timestamp)(struct AVFormatContext *s, int stream, int64_t *dts, int64_t *wall)
Definition: avformat.h:558
avformat_write_header
av_warn_unused_result int avformat_write_header(AVFormatContext *s, AVDictionary **options)
Allocate the stream private data and write the stream header to an output media file.
Definition: mux.c:468
AVFormatContext::max_analyze_duration
int64_t max_analyze_duration
Maximum duration (in AV_TIME_BASE units) of the data read from input in avformat_find_stream_info().
Definition: avformat.h:1263
AVFormatContext::correct_ts_overflow
unsigned int correct_ts_overflow
Correct single timestamp overflows.
Definition: avformat.h:1502
av_probe_input_format2
const AVInputFormat * av_probe_input_format2(const AVProbeData *pd, int is_opened, int *score_max)
Guess the file format.
Definition: format.c:205
AVOutputFormat::write_header
int(* write_header)(struct AVFormatContext *)
Definition: avformat.h:533
AVFormatContext
Format I/O context.
Definition: avformat.h:1106
AVFormatContext::audio_codec_id
enum AVCodecID audio_codec_id
Forced audio codec_id.
Definition: avformat.h:1281
av_probe_input_format
const AVInputFormat * av_probe_input_format(const AVProbeData *pd, int is_opened)
Guess the file format.
Definition: format.c:217
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:979
AVInputFormat::codec_tag
const struct AVCodecTag *const * codec_tag
Definition: avformat.h:644
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
AVStream::time_base
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition: avformat.h:855
flush
static void flush(AVCodecContext *avctx)
Definition: aacdec_template.c:592
AVFormatContext::max_streams
int max_streams
The maximum number of streams.
Definition: avformat.h:1681
AVFormatContext::fps_probe_size
int fps_probe_size
The number of frames used for determining the framerate in avformat_find_stream_info().
Definition: avformat.h:1349
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
AVFMT_DURATION_FROM_STREAM
@ AVFMT_DURATION_FROM_STREAM
Duration estimated from a stream with a known duration.
Definition: avformat.h:1086
AVFormatContext::protocol_whitelist
char * protocol_whitelist
',' separated list of allowed protocols.
Definition: avformat.h:1639
AVOutputFormat::get_device_list
int(* get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list)
Returns device list with it properties.
Definition: avformat.h:580
AVOutputFormat::long_name
const char * long_name
Descriptive name for the format, meant to be more human-readable than name.
Definition: avformat.h:497
av_stream_add_side_data
int av_stream_add_side_data(AVStream *st, enum AVPacketSideDataType type, uint8_t *data, size_t size)
Wrap an existing array as stream side data.
Definition: utils.c:5340
AVSTREAM_PARSE_NONE
@ AVSTREAM_PARSE_NONE
Definition: avformat.h:752
AVInputFormat::read_probe
int(* read_probe)(const AVProbeData *)
Tell if a given file has a chance of being parsed as this format.
Definition: avformat.h:677
AVIndexEntry::flags
int flags
Definition: avformat.h:772
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:1148
AVDurationEstimationMethod
AVDurationEstimationMethod
The duration of a video can be estimated through various ways, and this enum can be used to know how ...
Definition: avformat.h:1084
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
AVProgram::stream_index
unsigned int * stream_index
Definition: avformat.h:1032
AVStream::metadata
AVDictionary * metadata
Definition: avformat.h:890
time.h
AVFormatContext::skip_estimate_duration_from_pts
int skip_estimate_duration_from_pts
Skip duration calcuation in estimate_timings_from_pts.
Definition: avformat.h:1688
AVOutputFormat::priv_class
const AVClass * priv_class
AVClass for the private context.
Definition: avformat.h:519
av_write_frame
int av_write_frame(AVFormatContext *s, AVPacket *pkt)
Write a packet to an output media file.
Definition: mux.c:1174
AVFormatContext::audio_codec
const AVCodec * audio_codec
Forced audio codec.
Definition: avformat.h:1578
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
AVStream::nb_frames
int64_t nb_frames
number of frames in this stream if known or 0
Definition: avformat.h:877
AVCodecID
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:46
AVFormatContext::nb_streams
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1162
AVFormatContext::metadata_header_padding
int metadata_header_padding
Number of bytes to be written as padding in a metadata header.
Definition: avformat.h:1601
AVOutputFormat::flags
int flags
can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS,...
Definition: avformat.h:510
AVFormatContext::data_codec
const AVCodec * data_codec
Forced data codec.
Definition: avformat.h:1594
options
const OptionDef options[]
avformat_find_stream_info
int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
Read packets of a media file to get stream information.
Definition: utils.c:3543
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
AVProgram::pts_wrap_reference
int64_t pts_wrap_reference
reference dts for wrap detection
Definition: avformat.h:1051
AVMediaType
AVMediaType
Definition: avutil.h:199
avformat_match_stream_specifier
int avformat_match_stream_specifier(AVFormatContext *s, AVStream *st, const char *spec)
Check if the stream st contained in s is matched by the stream specifier spec.
Definition: utils.c:5144
id
enum AVCodecID id
Definition: extract_extradata_bsf.c:325
avformat_alloc_context
AVFormatContext * avformat_alloc_context(void)
Allocate an AVFormatContext.
Definition: options.c:166
av_codec_get_tag
unsigned int av_codec_get_tag(const struct AVCodecTag *const *tags, enum AVCodecID id)
Get the codec tag for the given codec id id.
AVProgram::end_time
int64_t end_time
Definition: avformat.h:1049
AVFormatContext::url
char * url
input or output URL.
Definition: avformat.h:1189
size
int size
Definition: twinvq_data.h:10344
avio.h
copy_tb
int copy_tb
Definition: ffmpeg_opt.c:165
avformat_seek_file
int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Seek to timestamp ts.
Definition: utils.c:2463
AVStream::event_flags
int event_flags
Flags indicating events happening on the stream, a combination of AVSTREAM_EVENT_FLAG_*.
Definition: avformat.h:945
av_guess_frame_rate
AVRational av_guess_frame_rate(AVFormatContext *ctx, AVStream *stream, AVFrame *frame)
Guess the frame rate, based on both the container and codec information.
Definition: utils.c:4991
av_stream_get_codec_timebase
AVRational av_stream_get_codec_timebase(const AVStream *st)
Get the internal codec timebase from a stream.
Definition: utils.c:5600
AVProgram::pts_wrap_behavior
int pts_wrap_behavior
behavior on wrap detection
Definition: avformat.h:1052
AVTimebaseSource
AVTimebaseSource
Definition: avformat.h:2739
av_demuxer_iterate
const AVInputFormat * av_demuxer_iterate(void **opaque)
Iterate over all registered demuxers.
Definition: allformats.c:554
AVProgram::program_num
int program_num
Definition: avformat.h:1036
AVStream::sample_aspect_ratio
AVRational sample_aspect_ratio
sample aspect ratio (0 if unknown)
Definition: avformat.h:888
AVFormatContext::keylen
int keylen
Definition: avformat.h:1266
av_sdp_create
int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size)
Generate an SDP for an RTP session.
Definition: sdp.c:828
av_format_inject_global_side_data
void av_format_inject_global_side_data(AVFormatContext *s)
This function will cause global side data to be injected in the next packet of each stream as well as...
Definition: utils.c:134
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
AVPacketSideDataType
AVPacketSideDataType
Definition: packet.h:40
av_probe_input_buffer
int av_probe_input_buffer(AVIOContext *pb, const AVInputFormat **fmt, const char *url, void *logctx, unsigned int offset, unsigned int max_probe_size)
Like av_probe_input_buffer2() but returns 0 on success.
Definition: format.c:313
AVOutputFormat::mime_type
const char * mime_type
Definition: avformat.h:498
AVFormatContext::skip_initial_bytes
int64_t skip_initial_bytes
Skip initial bytes when opening stream.
Definition: avformat.h:1495
AVStream::side_data
AVPacketSideData * side_data
An array of side data that applies to the whole stream (i.e.
Definition: avformat.h:928
av_warn_unused_result
#define av_warn_unused_result
Definition: attributes.h:64
AVFormatContext::error_recognition
int error_recognition
Error recognition; higher values will detect more errors but may misdetect some more or less valid pa...
Definition: avformat.h:1356
av_write_trailer
int av_write_trailer(AVFormatContext *s)
Write the stream trailer to an output media file and free the file private data.
Definition: mux.c:1236
AVStreamInternal
Definition: internal.h:170
log.h
AVOutputFormat
Definition: avformat.h:490
AVChapter::id
int64_t id
unique ID to identify the chapter
Definition: avformat.h:1064
AVInputFormat::priv_data_size
int priv_data_size
Size of private data so that it can be allocated in the wrapper.
Definition: avformat.h:670
AVOutputFormat::interleave_packet
int(* interleave_packet)(struct AVFormatContext *, AVPacket *out, AVPacket *in, int flush)
A format-specific function for interleavement.
Definition: avformat.h:547
avformat_get_mov_audio_tags
const struct AVCodecTag * avformat_get_mov_audio_tags(void)
Definition: isom_tags.c:343
AVProgram::metadata
AVDictionary * metadata
Definition: avformat.h:1034
avformat_index_get_entry
const AVIndexEntry * avformat_index_get_entry(AVStream *st, int idx)
Get the AVIndexEntry corresponding to the given index.
Definition: utils.c:2065
av_get_output_timestamp
int av_get_output_timestamp(struct AVFormatContext *s, int stream, int64_t *dts, int64_t *wall)
Get timing information for the data currently output.
Definition: mux.c:1281
AVFormatContext::codec_whitelist
char * codec_whitelist
',' separated list of allowed decoders.
Definition: avformat.h:1540
AVFormatContext::avoid_negative_ts
int avoid_negative_ts
Avoid negative timestamps during muxing.
Definition: avformat.h:1432
av_url_split
void av_url_split(char *proto, int proto_size, char *authorization, int authorization_size, char *hostname, int hostname_size, int *port_ptr, char *path, int path_size, const char *url)
Split a URL string into components.
Definition: utils.c:4653
av_find_default_stream_index
int av_find_default_stream_index(AVFormatContext *s)
Definition: utils.c:1778
AVFormatContext::max_delay
int max_delay
Definition: avformat.h:1218
AVFormatContext::io_repositioned
int io_repositioned
IO repositioned flag.
Definition: avformat.h:1562
AVProgram
New fields can be added to the end with minor version bumps.
Definition: avformat.h:1028
av_read_pause
int av_read_pause(AVFormatContext *s)
Pause a network-based stream (e.g.
Definition: utils.c:4195
AVInputFormat::read_packet
int(* read_packet)(struct AVFormatContext *, AVPacket *pkt)
Read one packet and put it in 'pkt'.
Definition: avformat.h:694
int_cb
const AVIOInterruptCB int_cb
Definition: ffmpeg.c:513
AVOutputFormat::control_message
int(* control_message)(struct AVFormatContext *s, int type, void *data, size_t data_size)
Allows sending messages from application to device.
Definition: avformat.h:563
av_get_packet
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:280
avcodec.h
AVCodecParserContext
Definition: avcodec.h:2876
AVInputFormat::get_device_list
int(* get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list)
Returns device list with it properties.
Definition: avformat.h:744
AVInputFormat::read_seek
int(* read_seek)(struct AVFormatContext *, int stream_index, int64_t timestamp, int flags)
Seek to a given timestamp relative to the frames in stream component stream_index.
Definition: avformat.h:710
version.h
AVStream::disposition
int disposition
AV_DISPOSITION_* bit field.
Definition: avformat.h:879
tag
uint32_t tag
Definition: movenc.c:1594
AVStream::id
int id
Format-specific stream ID.
Definition: avformat.h:839
AVStream
Stream structure.
Definition: avformat.h:832
AVFormatContext::ts_id
int ts_id
Transport stream id.
Definition: avformat.h:1441
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
av_hex_dump_log
void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size)
Send a nice hexadecimal dump of a buffer to the log.
Definition: dump.c:82
AVFormatContext::oformat
const struct AVOutputFormat * oformat
The output container format.
Definition: avformat.h:1125
AVDeviceInfoList
List of devices.
Definition: avdevice.h:465
AVStream::nb_side_data
int nb_side_data
The number of elements in the AVStream.side_data array.
Definition: avformat.h:932
av_append_packet
int av_append_packet(AVIOContext *s, AVPacket *pkt, int size)
Read data and append it to the current content of the AVPacket.
Definition: utils.c:296
AVSTREAM_PARSE_HEADERS
@ AVSTREAM_PARSE_HEADERS
Only parse headers, do not repack.
Definition: avformat.h:754
AVFormatContext::av_class
const AVClass * av_class
A class for logging and AVOptions.
Definition: avformat.h:1111
pos
unsigned int pos
Definition: spdifenc.c:412
av_stream_get_side_data
uint8_t * av_stream_get_side_data(const AVStream *stream, enum AVPacketSideDataType type, size_t *size)
Get side information from stream.
Definition: utils.c:5323
AVOutputFormat::write_uncoded_frame
int(* write_uncoded_frame)(struct AVFormatContext *, int stream_index, AVFrame **frame, unsigned flags)
Write an uncoded AVFrame.
Definition: avformat.h:574
dict.h
av_guess_codec
enum AVCodecID av_guess_codec(const AVOutputFormat *fmt, const char *short_name, const char *filename, const char *mime_type, enum AVMediaType type)
Guess the codec ID based upon muxer and filename.
Definition: format.c:87
ost
OutputStream * ost
Definition: ffmpeg_filter.c:163
avformat_network_deinit
int avformat_network_deinit(void)
Undo the initialization done by avformat_network_init.
Definition: utils.c:4917
AVFormatContext::debug
int debug
Flags to enable debugging.
Definition: avformat.h:1372
AVFormatContext::data_codec_id
enum AVCodecID data_codec_id
Forced Data codec_id.
Definition: avformat.h:1632
AVStream::index
int index
stream index in AVFormatContext
Definition: avformat.h:833
AVInputFormat::read_seek2
int(* read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Seek to timestamp ts.
Definition: avformat.h:738
av_muxer_iterate
const AVOutputFormat * av_muxer_iterate(void **opaque)
Iterate over all registered muxers.
Definition: allformats.c:537
avformat_transfer_internal_stream_timing_info
int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt, AVStream *ost, const AVStream *ist, enum AVTimebaseSource copy_tb)
Transfer internal timing information from one stream to another.
Definition: utils.c:5538
format_name
static int format_name(const char *buf, char **s, int index, const char *varname)
Definition: hlsenc.c:1923
AVInputFormat::read_close
int(* read_close)(struct AVFormatContext *)
Close the stream.
Definition: avformat.h:700
AVFormatContext::seek2any
int seek2any
Force seeking to any (also non key) frames.
Definition: avformat.h:1509
AVInputFormat::flags
int flags
Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS, AVFMT_NOTIMESTAMPS,...
Definition: avformat.h:635
AVInputFormat::read_pause
int(* read_pause)(struct AVFormatContext *)
Pause playing - only meaningful if using a network-based format (RTSP).
Definition: avformat.h:730
av_stream_get_end_pts
int64_t av_stream_get_end_pts(const AVStream *st)
Returns the pts of the last muxed packet + its duration.
Definition: utils.c:116
avformat_free_context
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
Definition: utils.c:4301
AVFormatContext::io_close
void(* io_close)(struct AVFormatContext *s, AVIOContext *pb)
A callback for closing the streams opened with AVFormatContext.io_open().
Definition: avformat.h:1667
AVOutputFormat::video_codec
enum AVCodecID video_codec
default video codec
Definition: avformat.h:502
AVStream::r_frame_rate
AVRational r_frame_rate
Real base framerate of the stream.
Definition: avformat.h:968
AVFormatContext::io_open
int(* io_open)(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags, AVDictionary **options)
A callback for opening new IO streams.
Definition: avformat.h:1661
AVIndexEntry::pos
int64_t pos
Definition: avformat.h:763
AVSTREAM_PARSE_FULL_RAW
@ AVSTREAM_PARSE_FULL_RAW
full parsing and repack with timestamp and position generation by parser for raw this assumes that ea...
Definition: avformat.h:757
av_find_input_format
const AVInputFormat * av_find_input_format(const char *short_name)
Find AVInputFormat based on the short name of the input format.
Definition: format.c:118
AVFormatContext::duration
int64_t duration
Duration of the stream, in AV_TIME_BASE fractional seconds.
Definition: avformat.h:1208
avformat_license
const char * avformat_license(void)
Return the libavformat license.
Definition: utils.c:73
AVFormatContext::packet_size
unsigned int packet_size
Definition: avformat.h:1217
av_guess_format
const AVOutputFormat * av_guess_format(const char *short_name, const char *filename, const char *mime_type)
Return the output format in the list of registered output formats which best matches the provided par...
Definition: format.c:51
AVFormatContext::start_time_realtime
int64_t start_time_realtime
Start time of the stream in real world time, in microseconds since the Unix epoch (00:00 1st January ...
Definition: avformat.h:1342
avformat_configuration
const char * avformat_configuration(void)
Return the libavformat build-time configuration.
Definition: utils.c:68
AVFormatContext::max_probe_packets
int max_probe_packets
Maximum number of packets that can be probed.
Definition: avformat.h:1695
AVPacket
This structure stores compressed data.
Definition: packet.h:342
AVFormatContext::use_wallclock_as_timestamps
int use_wallclock_as_timestamps
forces the use of wallclock timestamps as pts/dts of packets This has undefined results in the presen...
Definition: avformat.h:1473
av_interleaved_write_frame
int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
Write a packet to an output media file ensuring correct interleaving.
Definition: mux.c:1221
format
fg outputs[0] format
Definition: ffmpeg_filter.c:175
av_stream_new_side_data
uint8_t * av_stream_new_side_data(AVStream *stream, enum AVPacketSideDataType type, size_t size)
Allocate new information from stream.
Definition: utils.c:5376
distance
static float distance(float x, float y, int band)
Definition: nellymoserenc.c:233
AVSTREAM_PARSE_FULL
@ AVSTREAM_PARSE_FULL
full parsing and repack
Definition: avformat.h:753
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
AVInputFormat::read_timestamp
int64_t(* read_timestamp)(struct AVFormatContext *s, int stream_index, int64_t *pos, int64_t pos_limit)
Get the next timestamp in stream[stream_index].time_base units.
Definition: avformat.h:717
AVFormatContext::start_time
int64_t start_time
Position of the first frame of the component, in AV_TIME_BASE fractional seconds.
Definition: avformat.h:1198
av_stream_get_parser
struct AVCodecParserContext * av_stream_get_parser(const AVStream *s)
Definition: utils.c:124
av_pkt_dump_log2
void av_pkt_dump_log2(void *avcl, int level, const AVPacket *pkt, int dump_payload, const AVStream *st)
Send a nice dump of a packet to the log.
Definition: dump.c:116
AVStream::start_time
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base.
Definition: avformat.h:865
AVSTREAM_PARSE_TIMESTAMPS
@ AVSTREAM_PARSE_TIMESTAMPS
full parsing and interpolation of timestamps for frames not starting on a packet boundary
Definition: avformat.h:755
AVFormatContext::avio_flags
int avio_flags
avio flags, used to force AVIO_FLAG_DIRECT.
Definition: avformat.h:1480
AVOutputFormat::query_codec
int(* query_codec)(enum AVCodecID id, int std_compliance)
Test if the given codec can be stored in this container.
Definition: avformat.h:556
AVDiscard
AVDiscard
Definition: avcodec.h:204
avformat_alloc_output_context2
int avformat_alloc_output_context2(AVFormatContext **ctx, const AVOutputFormat *oformat, const char *format_name, const char *filename)
Allocate an AVFormatContext for an output format.
Definition: mux.c:136
AVStream::pts_wrap_bits
int pts_wrap_bits
number of bits in pts (used for wrapping control)
Definition: avformat.h:991
AVInputFormat::read_header
int(* read_header)(struct AVFormatContext *)
Read the format header and initialize the AVFormatContext structure.
Definition: avformat.h:684
AVChapter::time_base
AVRational time_base
time base in which the start/end timestamps are specified
Definition: avformat.h:1065
int
int
Definition: ffmpeg_filter.c:156
AVFormatContext::priv_data
void * priv_data
Format private data.
Definition: avformat.h:1134
AVProgram::pcr_pid
int pcr_pid
Definition: avformat.h:1038
AVFormatContext::key
const uint8_t * key
Definition: avformat.h:1265
AVInputFormat::priv_class
const AVClass * priv_class
AVClass for the private context.
Definition: avformat.h:646
AVFormatContext::max_chunk_size
int max_chunk_size
Max chunk size in bytes Note, not all formats support this and unpredictable things may happen if it ...
Definition: avformat.h:1465
av_index_search_timestamp
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: utils.c:2054
AVFormatContext::video_codec
const AVCodec * video_codec
Forced video codec.
Definition: avformat.h:1570
AVInputFormat::read_play
int(* read_play)(struct AVFormatContext *)
Start/resume playing - only meaningful if using a network-based format (RTSP).
Definition: avformat.h:724
av_program_add_stream_index
void av_program_add_stream_index(AVFormatContext *ac, int progid, unsigned int idx)
AVFormatContext::subtitle_codec_id
enum AVCodecID subtitle_codec_id
Forced subtitle codec_id.
Definition: avformat.h:1287
AVOutputFormat::priv_data_size
int priv_data_size
size of private data so that it can be allocated in the wrapper
Definition: avformat.h:531
av_hex_dump
void av_hex_dump(FILE *f, const uint8_t *buf, int size)
Send a nice hexadecimal dump of a buffer to the specified file stream.
Definition: dump.c:77