2 * copyright (c) 2001 Fabrice Bellard
4 * This file is part of FFmpeg.
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.
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.
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
21 #ifndef AVFORMAT_AVFORMAT_H
22 #define AVFORMAT_AVFORMAT_H
27 * Main libavformat public API header
31 * @defgroup libavf libavformat
32 * I/O and Muxing/Demuxing Library
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().
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.
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).
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).
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.
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.
84 * It is important that the scheme string is not taken from untrusted
85 * sources without checks.
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.
93 * @defgroup lavf_decoding Demuxing
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
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:
106 * const char *url = "file:in.mp3";
107 * AVFormatContext *s = NULL;
108 * int ret = avformat_open_input(&s, url, NULL, NULL);
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.
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.
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:
132 * AVDictionary *options = NULL;
133 * av_dict_set(&options, "video_size", "640x480", 0);
134 * av_dict_set(&options, "pixel_format", "rgb24", 0);
136 * if (avformat_open_input(&s, url, NULL, &options) < 0)
138 * av_dict_free(&options);
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
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);
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.
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.
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.
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
178 * @section lavf_decoding_seek Seeking
181 * @defgroup lavf_encoding Muxing
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.
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.
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:
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
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
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.
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.
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().
241 * @defgroup lavf_io I/O Read/Write
243 * @section lavf_io_dirlist Directory listing
244 * The directory listing API makes it possible to list files on remote servers.
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.
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.
258 * AVIODirContext *ctx = NULL;
259 * if (avio_open_dir(&ctx, "smb://example.com/some_dir", NULL) < 0) {
260 * fprintf(stderr, "Cannot open directory.\n");
265 * This code tries to open a sample directory using smb protocol without
266 * any additional parameters.
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.
278 * AVIODirEntry *entry = NULL;
280 * if (avio_read_dir(ctx, &entry) < 0) {
281 * fprintf(stderr, "Cannot list directory.\n");
286 * printf("%s\n", entry->name);
287 * avio_free_directory_entry(&entry);
292 * @defgroup lavf_codec Demuxers
294 * @defgroup lavf_codec_native Native Demuxers
297 * @defgroup lavf_codec_wrappers External library wrappers
301 * @defgroup lavf_protos I/O Protocols
304 * @defgroup lavf_internal Internal
311 #include <stdio.h> /* FILE */
312 #include "libavcodec/avcodec.h"
313 #include "libavutil/dict.h"
314 #include "libavutil/log.h"
317 #include "libavformat/version.h"
319 struct AVFormatContext;
321 struct AVDeviceInfoList;
322 struct AVDeviceCapabilitiesQuery;
325 * @defgroup metadata_api Public Metadata API
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.
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.
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.
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:
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
397 * Look in the examples section for an application example how to use the Metadata API.
402 /* packet functions */
406 * Allocate and read the payload of a packet and initialize its
407 * fields with default values.
409 * @param s associated IO context
411 * @param size desired payload size
412 * @return >0 (read size) if OK, AVERROR_xxx otherwise
414 int av_get_packet(AVIOContext *s, AVPacket *pkt, int size);
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)
425 * @param s associated IO context
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.
431 int av_append_packet(AVIOContext *s, AVPacket *pkt, int size);
433 /*************************************************/
434 /* input/output formats */
439 * This structure contains the data a format has to probe a file.
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. */
448 #define AVPROBE_SCORE_RETRY (AVPROBE_SCORE_MAX/4)
449 #define AVPROBE_SCORE_STREAM_RETRY (AVPROBE_SCORE_MAX/4-1)
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
455 #define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
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
480 The user or muxer can override this through
481 AVFormatContext.avoid_negative_ts
484 #define AVFMT_SEEK_TO_PTS 0x4000000 /**< Seeking is based on PTS */
487 * @addtogroup lavf_encoding
490 typedef struct AVOutputFormat {
493 * Descriptive name for the format, meant to be more human-readable
494 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
497 const char *long_name;
498 const char *mime_type;
499 const char *extensions; /**< comma-separated filename extensions */
501 enum AVCodecID audio_codec; /**< default audio codec */
502 enum AVCodecID video_codec; /**< default video codec */
503 enum AVCodecID subtitle_codec; /**< default subtitle codec */
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
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.
516 const struct AVCodecTag * const *codec_tag;
519 const AVClass *priv_class; ///< AVClass for the private context
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
525 * New public fields should be added right above.
526 *****************************************************************
529 * size of private data so that it can be allocated in the wrapper
533 int (*write_header)(struct AVFormatContext *);
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
541 int (*write_packet)(struct AVFormatContext *, AVPacket *pkt);
542 int (*write_trailer)(struct AVFormatContext *);
544 * A format-specific function for interleavement.
545 * If unset, packets will be interleaved by dts.
547 int (*interleave_packet)(struct AVFormatContext *, AVPacket *out,
548 AVPacket *in, int flush);
550 * Test if the given codec can be stored in this container.
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
556 int (*query_codec)(enum AVCodecID id, int std_compliance);
558 void (*get_output_timestamp)(struct AVFormatContext *s, int stream,
559 int64_t *dts, int64_t *wall);
561 * Allows sending messages from application to device.
563 int (*control_message)(struct AVFormatContext *s, int type,
564 void *data, size_t data_size);
567 * Write an uncoded AVFrame.
569 * See av_write_uncoded_frame() for details.
571 * The library will free *frame afterwards, but the muxer can prevent it
572 * by setting the pointer to NULL.
574 int (*write_uncoded_frame)(struct AVFormatContext *, int stream_index,
575 AVFrame **frame, unsigned flags);
577 * Returns device list with it properties.
578 * @see avdevice_list_devices() for more details.
580 int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list);
581 enum AVCodecID data_codec; /**< default data codec */
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.
587 * Return 0 if streams were fully configured, 1 if not, negative AVERROR on failure
589 * Any allocations made here must be freed in deinit().
591 int (*init)(struct AVFormatContext *);
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.
596 * If a trailer is being written, this is called after write_trailer().
598 * This is called if init() fails as well.
600 void (*deinit)(struct AVFormatContext *);
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.
606 int (*check_bitstream)(struct AVFormatContext *, const AVPacket *pkt);
613 * @addtogroup lavf_decoding
616 typedef struct AVInputFormat {
618 * A comma separated list of short names for the format. New names
619 * may be appended with a minor bump.
624 * Descriptive name for the format, meant to be more human-readable
625 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
628 const char *long_name;
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.
638 * If extensions are defined, then no probe is done. You should
639 * usually not use extension format guessing because it is not
642 const char *extensions;
644 const struct AVCodecTag * const *codec_tag;
646 const AVClass *priv_class; ///< AVClass for the private context
649 * Comma-separated list of mime types.
650 * It is used check for matching mime types while probing.
651 * @see av_probe_input_format2
653 const char *mime_type;
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
659 * New public fields should be added right above.
660 *****************************************************************
663 * Raw demuxers store their codec ID here.
668 * Size of private data so that it can be allocated in the wrapper.
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.
677 int (*read_probe)(const AVProbeData *);
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.
684 int (*read_header)(struct AVFormatContext *);
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.
694 int (*read_packet)(struct AVFormatContext *, AVPacket *pkt);
697 * Close the stream. The AVFormatContext and AVStreams are not
698 * freed by this function
700 int (*read_close)(struct AVFormatContext *);
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)
710 int (*read_seek)(struct AVFormatContext *,
711 int stream_index, int64_t timestamp, int flags);
714 * Get the next timestamp in stream[stream_index].time_base units.
715 * @return the timestamp or AV_NOPTS_VALUE if an error occurred
717 int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index,
718 int64_t *pos, int64_t pos_limit);
721 * Start/resume playing - only meaningful if using a network-based format
724 int (*read_play)(struct AVFormatContext *);
727 * Pause playing - only meaningful if using a network-based format
730 int (*read_pause)(struct AVFormatContext *);
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.
738 int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
741 * Returns device list with it properties.
742 * @see avdevice_list_devices() for more details.
744 int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list);
751 enum AVStreamParseType {
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 */
762 typedef struct AVIndexEntry {
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
770 #define AVINDEX_KEYFRAME 0x0001
771 #define AVINDEX_DISCARD_FRAME 0x0002 /**
772 * Flag is used to indicate which frame should be discarded after decoding.
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. */
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
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.
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 */
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.
802 #define AV_DISPOSITION_ATTACHED_PIC 0x0400
804 * The stream is sparse, and contains thumbnail images, often corresponding
805 * to chapter markers. Only ever used with AV_DISPOSITION_ATTACHED_PIC.
807 #define AV_DISPOSITION_TIMED_THUMBNAILS 0x0800
809 typedef struct AVStreamInternal AVStreamInternal;
812 * To specify text track kind (different from subtitles default).
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)
821 * Options for behavior on timestamp wrap detection.
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
829 * New fields can be added to the end with minor version bumps.
830 * Removal, reordering and changes to existing fields require a major
832 * sizeof(AVStream) must not be used outside libav*.
834 typedef struct AVStream {
835 int index; /**< stream index in AVFormatContext */
837 * Format-specific stream ID.
838 * decoding: set by libavformat
839 * encoding: set by the user, replaced by libavformat if left unset
842 #if FF_API_LAVF_AVCTX
844 * @deprecated use the codecpar struct instead
847 AVCodecContext *codec;
852 * This is the fundamental unit of time (in seconds) in terms
853 * of which frame timestamps are represented.
855 * decoding: set by libavformat
856 * encoding: May be set by the caller before avformat_write_header() to
857 * provide a hint to the muxer about the desired timebase. In
858 * avformat_write_header(), the muxer will overwrite this field
859 * with the timebase that will actually be used for the timestamps
860 * written into the file (which may or may not be related to the
861 * user-provided one, depending on the format).
863 AVRational time_base;
866 * Decoding: pts of the first frame of the stream in presentation order, in stream time base.
867 * Only set this if you are absolutely 100% sure that the value you set
868 * it to really is the pts of the first frame.
869 * This may be undefined (AV_NOPTS_VALUE).
870 * @note The ASF header does NOT contain a correct start_time the ASF
871 * demuxer must NOT set this.
876 * Decoding: duration of the stream, in stream time base.
877 * If a source file does not specify a duration, but does specify
878 * a bitrate, this value will be estimated from bitrate and file size.
880 * Encoding: May be set by the caller before avformat_write_header() to
881 * provide a hint to the muxer about the estimated duration.
885 int64_t nb_frames; ///< number of frames in this stream if known or 0
887 int disposition; /**< AV_DISPOSITION_* bit field */
889 enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
892 * sample aspect ratio (0 if unknown)
893 * - encoding: Set by user.
894 * - decoding: Set by libavformat.
896 AVRational sample_aspect_ratio;
898 AVDictionary *metadata;
903 * - demuxing: May be set by libavformat when creating the stream or in
904 * avformat_find_stream_info().
905 * - muxing: May be set by the caller before avformat_write_header().
907 AVRational avg_frame_rate;
910 * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
911 * will contain the attached picture.
913 * decoding: set by libavformat, must not be modified by the caller.
916 AVPacket attached_pic;
919 * An array of side data that applies to the whole stream (i.e. the
920 * container does not allow it to change between packets).
922 * There may be no overlap between the side data in this array and side data
923 * in the packets. I.e. a given side data is either exported by the muxer
924 * (demuxing) / set by the caller (muxing) in this array, then it never
925 * appears in the packets, or the side data is exported / sent through
926 * the packets (always in the first packet where the value becomes known or
927 * changes), then it does not appear in this array.
929 * - demuxing: Set by libavformat when the stream is created.
930 * - muxing: May be set by the caller before avformat_write_header().
932 * Freed by libavformat in avformat_free_context().
934 * @see av_format_inject_global_side_data()
936 AVPacketSideData *side_data;
938 * The number of elements in the AVStream.side_data array.
943 * Flags indicating events happening on the stream, a combination of
944 * AVSTREAM_EVENT_FLAG_*.
946 * - demuxing: may be set by the demuxer in avformat_open_input(),
947 * avformat_find_stream_info() and av_read_frame(). Flags must be cleared
948 * by the user once the event has been handled.
949 * - muxing: may be set by the user after avformat_write_header(). to
950 * indicate a user-triggered event. The muxer will clear the flags for
951 * events it has handled in av_[interleaved]_write_frame().
955 * - demuxing: the demuxer read new metadata from the file and updated
956 * AVStream.metadata accordingly
957 * - muxing: the user updated AVStream.metadata and wishes the muxer to write
960 #define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001
962 * - demuxing: new packets for this stream were read from the file. This
963 * event is informational only and does not guarantee that new packets
964 * for this stream will necessarily be returned from av_read_frame().
966 #define AVSTREAM_EVENT_FLAG_NEW_PACKETS (1 << 1)
969 * Real base framerate of the stream.
970 * This is the lowest framerate with which all timestamps can be
971 * represented accurately (it is the least common multiple of all
972 * framerates in the stream). Note, this value is just a guess!
973 * For example, if the time base is 1/90000 and all frames have either
974 * approximately 3600 or 1800 timer ticks, then r_frame_rate will be 50/1.
976 AVRational r_frame_rate;
979 * Codec parameters associated with this stream. Allocated and freed by
980 * libavformat in avformat_new_stream() and avformat_free_context()
983 * - demuxing: filled by libavformat on stream creation or in
984 * avformat_find_stream_info()
985 * - muxing: filled by the caller before avformat_write_header()
987 AVCodecParameters *codecpar;
989 /*****************************************************************
990 * All fields below this line are not part of the public API. They
991 * may not be used outside of libavformat and can be changed and
993 * Internal note: be aware that physically removing these fields
994 * will break ABI. Replace removed fields with dummy fields, and
995 * add new fields to AVStreamInternal.
996 *****************************************************************
999 int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
1001 // Timestamp generation support:
1003 * Timestamp corresponding to the last dts sync point.
1005 * Initialized when AVCodecParserContext.dts_sync_point >= 0 and
1006 * a DTS is received from the underlying container. Otherwise set to
1007 * AV_NOPTS_VALUE by default.
1011 int64_t last_IP_pts;
1012 int last_IP_duration;
1015 * Number of packets to buffer for codec probing
1020 * Number of frames that have been demuxed during avformat_find_stream_info()
1022 int codec_info_nb_frames;
1024 /* av_read_frame() support */
1025 enum AVStreamParseType need_parsing;
1026 struct AVCodecParserContext *parser;
1030 * This is the MPEG-TS stream identifier +1
1033 int stream_identifier;
1036 * An opaque field for libavformat internal usage.
1037 * Must not be accessed in any way by callers.
1039 AVStreamInternal *internal;
1042 struct AVCodecParserContext *av_stream_get_parser(const AVStream *s);
1045 * Returns the pts of the last muxed packet + its duration
1047 * the retuned value is undefined when used with a demuxer.
1049 int64_t av_stream_get_end_pts(const AVStream *st);
1051 #define AV_PROGRAM_RUNNING 1
1054 * New fields can be added to the end with minor version bumps.
1055 * Removal, reordering and changes to existing fields require a major
1057 * sizeof(AVProgram) must not be used outside libav*.
1059 typedef struct AVProgram {
1062 enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
1063 unsigned int *stream_index;
1064 unsigned int nb_stream_indexes;
1065 AVDictionary *metadata;
1072 /*****************************************************************
1073 * All fields below this line are not part of the public API. They
1074 * may not be used outside of libavformat and can be changed and
1076 * New public fields should be added right above.
1077 *****************************************************************
1082 int64_t pts_wrap_reference; ///< reference dts for wrap detection
1083 int pts_wrap_behavior; ///< behavior on wrap detection
1086 #define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
1087 (streams are added dynamically) */
1088 #define AVFMTCTX_UNSEEKABLE 0x0002 /**< signal that the stream is definitely
1089 not seekable, and attempts to call the
1090 seek function will fail. For some
1091 network protocols (e.g. HLS), this can
1092 change dynamically at runtime. */
1094 typedef struct AVChapter {
1095 int64_t id; ///< unique ID to identify the chapter
1096 AVRational time_base; ///< time base in which the start/end timestamps are specified
1097 int64_t start, end; ///< chapter start/end time in time_base units
1098 AVDictionary *metadata;
1103 * Callback used by devices to communicate with application.
1105 typedef int (*av_format_control_message)(struct AVFormatContext *s, int type,
1106 void *data, size_t data_size);
1108 typedef int (*AVOpenCallback)(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags,
1109 const AVIOInterruptCB *int_cb, AVDictionary **options);
1112 * The duration of a video can be estimated through various ways, and this enum can be used
1113 * to know how the duration was estimated.
1115 enum AVDurationEstimationMethod {
1116 AVFMT_DURATION_FROM_PTS, ///< Duration accurately estimated from PTSes
1117 AVFMT_DURATION_FROM_STREAM, ///< Duration estimated from a stream with a known duration
1118 AVFMT_DURATION_FROM_BITRATE ///< Duration estimated from bitrate (less accurate)
1121 typedef struct AVFormatInternal AVFormatInternal;
1124 * Format I/O context.
1125 * New fields can be added to the end with minor version bumps.
1126 * Removal, reordering and changes to existing fields require a major
1128 * sizeof(AVFormatContext) must not be used outside libav*, use
1129 * avformat_alloc_context() to create an AVFormatContext.
1131 * Fields can be accessed through AVOptions (av_opt*),
1132 * the name string used matches the associated command line parameter name and
1133 * can be found in libavformat/options_table.h.
1134 * The AVOption/command line parameter names differ in some cases from the C
1135 * structure field names for historic reasons or brevity.
1137 typedef struct AVFormatContext {
1139 * A class for logging and @ref avoptions. Set by avformat_alloc_context().
1140 * Exports (de)muxer private options if they exist.
1142 const AVClass *av_class;
1145 * The input container format.
1147 * Demuxing only, set by avformat_open_input().
1149 const struct AVInputFormat *iformat;
1152 * The output container format.
1154 * Muxing only, must be set by the caller before avformat_write_header().
1156 const struct AVOutputFormat *oformat;
1159 * Format private data. This is an AVOptions-enabled struct
1160 * if and only if iformat/oformat.priv_class is not NULL.
1162 * - muxing: set by avformat_write_header()
1163 * - demuxing: set by avformat_open_input()
1170 * - demuxing: either set by the user before avformat_open_input() (then
1171 * the user must close it manually) or set by avformat_open_input().
1172 * - muxing: set by the user before avformat_write_header(). The caller must
1173 * take care of closing / freeing the IO context.
1175 * Do NOT set this field if AVFMT_NOFILE flag is set in
1176 * iformat/oformat.flags. In such a case, the (de)muxer will handle
1177 * I/O in some other way and this field will be NULL.
1183 * Flags signalling stream properties. A combination of AVFMTCTX_*.
1184 * Set by libavformat.
1189 * Number of elements in AVFormatContext.streams.
1191 * Set by avformat_new_stream(), must not be modified by any other code.
1193 unsigned int nb_streams;
1195 * A list of all streams in the file. New streams are created with
1196 * avformat_new_stream().
1198 * - demuxing: streams are created by libavformat in avformat_open_input().
1199 * If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
1200 * appear in av_read_frame().
1201 * - muxing: streams are created by the user before avformat_write_header().
1203 * Freed by libavformat in avformat_free_context().
1208 * input or output URL. Unlike the old filename field, this field has no
1209 * length restriction.
1211 * - demuxing: set by avformat_open_input(), initialized to an empty
1212 * string if url parameter was NULL in avformat_open_input().
1213 * - muxing: may be set by the caller before calling avformat_write_header()
1214 * (or avformat_init_output() if that is called first) to a string
1215 * which is freeable by av_free(). Set to an empty string if it
1216 * was NULL in avformat_init_output().
1218 * Freed by libavformat in avformat_free_context().
1223 * Position of the first frame of the component, in
1224 * AV_TIME_BASE fractional seconds. NEVER set this value directly:
1225 * It is deduced from the AVStream values.
1227 * Demuxing only, set by libavformat.
1232 * Duration of the stream, in AV_TIME_BASE fractional
1233 * seconds. Only set this value if you know none of the individual stream
1234 * durations and also do not set any of them. This is deduced from the
1235 * AVStream values if not set.
1237 * Demuxing only, set by libavformat.
1242 * Total stream bitrate in bit/s, 0 if not
1243 * available. Never set it directly if the file_size and the
1244 * duration are known as FFmpeg can compute it automatically.
1248 unsigned int packet_size;
1252 * Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
1253 * Set by the user before avformat_open_input() / avformat_write_header().
1256 #define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
1257 #define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
1258 #define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
1259 #define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
1260 #define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container
1261 #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
1262 #define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
1263 #define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
1264 #define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
1265 #define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
1267 * When muxing, try to avoid writing any random/volatile data to the output.
1268 * This includes any random IDs, real-time timestamps/dates, muxer version, etc.
1270 * This flag is mainly intended for testing.
1272 #define AVFMT_FLAG_BITEXACT 0x0400
1273 #define AVFMT_FLAG_SORT_DTS 0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
1274 #if FF_API_LAVF_PRIV_OPT
1275 #define AVFMT_FLAG_PRIV_OPT 0x20000 ///< Enable use of private options by delaying codec open (deprecated, does nothing)
1277 #define AVFMT_FLAG_FAST_SEEK 0x80000 ///< Enable fast, but inaccurate seeks for some formats
1278 #define AVFMT_FLAG_SHORTEST 0x100000 ///< Stop muxing when the shortest stream stops.
1279 #define AVFMT_FLAG_AUTO_BSF 0x200000 ///< Add bitstream filters as requested by the muxer
1282 * Maximum size of the data read from input for determining
1283 * the input container format.
1284 * Demuxing only, set by the caller before avformat_open_input().
1289 * Maximum duration (in AV_TIME_BASE units) of the data read
1290 * from input in avformat_find_stream_info().
1291 * Demuxing only, set by the caller before avformat_find_stream_info().
1292 * Can be set to 0 to let avformat choose using a heuristic.
1294 int64_t max_analyze_duration;
1299 unsigned int nb_programs;
1300 AVProgram **programs;
1303 * Forced video codec_id.
1304 * Demuxing: Set by user.
1306 enum AVCodecID video_codec_id;
1309 * Forced audio codec_id.
1310 * Demuxing: Set by user.
1312 enum AVCodecID audio_codec_id;
1315 * Forced subtitle codec_id.
1316 * Demuxing: Set by user.
1318 enum AVCodecID subtitle_codec_id;
1321 * Maximum amount of memory in bytes to use for the index of each stream.
1322 * If the index exceeds this size, entries will be discarded as
1323 * needed to maintain a smaller size. This can lead to slower or less
1324 * accurate seeking (depends on demuxer).
1325 * Demuxers for which a full in-memory index is mandatory will ignore
1328 * - demuxing: set by user
1330 unsigned int max_index_size;
1333 * Maximum amount of memory in bytes to use for buffering frames
1334 * obtained from realtime capture devices.
1336 unsigned int max_picture_buffer;
1339 * Number of chapters in AVChapter array.
1340 * When muxing, chapters are normally written in the file header,
1341 * so nb_chapters should normally be initialized before write_header
1342 * is called. Some muxers (e.g. mov and mkv) can also write chapters
1343 * in the trailer. To write chapters in the trailer, nb_chapters
1344 * must be zero when write_header is called and non-zero when
1345 * write_trailer is called.
1346 * - muxing: set by user
1347 * - demuxing: set by libavformat
1349 unsigned int nb_chapters;
1350 AVChapter **chapters;
1353 * Metadata that applies to the whole file.
1355 * - demuxing: set by libavformat in avformat_open_input()
1356 * - muxing: may be set by the caller before avformat_write_header()
1358 * Freed by libavformat in avformat_free_context().
1360 AVDictionary *metadata;
1363 * Start time of the stream in real world time, in microseconds
1364 * since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1365 * stream was captured at this real world time.
1366 * - muxing: Set by the caller before avformat_write_header(). If set to
1367 * either 0 or AV_NOPTS_VALUE, then the current wall-time will
1369 * - demuxing: Set by libavformat. AV_NOPTS_VALUE if unknown. Note that
1370 * the value may become known after some number of frames
1371 * have been received.
1373 int64_t start_time_realtime;
1376 * The number of frames used for determining the framerate in
1377 * avformat_find_stream_info().
1378 * Demuxing only, set by the caller before avformat_find_stream_info().
1383 * Error recognition; higher values will detect more errors but may
1384 * misdetect some more or less valid parts as errors.
1385 * Demuxing only, set by the caller before avformat_open_input().
1387 int error_recognition;
1390 * Custom interrupt callbacks for the I/O layer.
1392 * demuxing: set by the user before avformat_open_input().
1393 * muxing: set by the user before avformat_write_header()
1394 * (mainly useful for AVFMT_NOFILE formats). The callback
1395 * should also be passed to avio_open2() if it's used to
1398 AVIOInterruptCB interrupt_callback;
1401 * Flags to enable debugging.
1404 #define FF_FDEBUG_TS 0x0001
1407 * Maximum buffering duration for interleaving.
1409 * To ensure all the streams are interleaved correctly,
1410 * av_interleaved_write_frame() will wait until it has at least one packet
1411 * for each stream before actually writing any packets to the output file.
1412 * When some streams are "sparse" (i.e. there are large gaps between
1413 * successive packets), this can result in excessive buffering.
1415 * This field specifies the maximum difference between the timestamps of the
1416 * first and the last packet in the muxing queue, above which libavformat
1417 * will output a packet regardless of whether it has queued a packet for all
1420 * Muxing only, set by the caller before avformat_write_header().
1422 int64_t max_interleave_delta;
1425 * Allow non-standard and experimental extension
1426 * @see AVCodecContext.strict_std_compliance
1428 int strict_std_compliance;
1431 * Flags indicating events happening on the file, a combination of
1432 * AVFMT_EVENT_FLAG_*.
1434 * - demuxing: may be set by the demuxer in avformat_open_input(),
1435 * avformat_find_stream_info() and av_read_frame(). Flags must be cleared
1436 * by the user once the event has been handled.
1437 * - muxing: may be set by the user after avformat_write_header() to
1438 * indicate a user-triggered event. The muxer will clear the flags for
1439 * events it has handled in av_[interleaved]_write_frame().
1443 * - demuxing: the demuxer read new metadata from the file and updated
1444 * AVFormatContext.metadata accordingly
1445 * - muxing: the user updated AVFormatContext.metadata and wishes the muxer to
1446 * write it into the file
1448 #define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001
1451 * Maximum number of packets to read while waiting for the first timestamp.
1457 * Avoid negative timestamps during muxing.
1458 * Any value of the AVFMT_AVOID_NEG_TS_* constants.
1459 * Note, this only works when using av_interleaved_write_frame. (interleave_packet_per_dts is in use)
1460 * - muxing: Set by user
1461 * - demuxing: unused
1463 int avoid_negative_ts;
1464 #define AVFMT_AVOID_NEG_TS_AUTO -1 ///< Enabled when required by target format
1465 #define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
1466 #define AVFMT_AVOID_NEG_TS_MAKE_ZERO 2 ///< Shift timestamps so that they start at 0
1469 * Transport stream id.
1470 * This will be moved into demuxer private options. Thus no API/ABI compatibility
1475 * Audio preload in microseconds.
1476 * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1477 * - encoding: Set by user
1478 * - decoding: unused
1483 * Max chunk time in microseconds.
1484 * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1485 * - encoding: Set by user
1486 * - decoding: unused
1488 int max_chunk_duration;
1491 * Max chunk size in bytes
1492 * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1493 * - encoding: Set by user
1494 * - decoding: unused
1499 * forces the use of wallclock timestamps as pts/dts of packets
1500 * This has undefined results in the presence of B frames.
1501 * - encoding: unused
1502 * - decoding: Set by user
1504 int use_wallclock_as_timestamps;
1507 * avio flags, used to force AVIO_FLAG_DIRECT.
1508 * - encoding: unused
1509 * - decoding: Set by user
1514 * The duration field can be estimated through various ways, and this field can be used
1515 * to know how the duration was estimated.
1516 * - encoding: unused
1517 * - decoding: Read by user
1519 enum AVDurationEstimationMethod duration_estimation_method;
1522 * Skip initial bytes when opening stream
1523 * - encoding: unused
1524 * - decoding: Set by user
1526 int64_t skip_initial_bytes;
1529 * Correct single timestamp overflows
1530 * - encoding: unused
1531 * - decoding: Set by user
1533 unsigned int correct_ts_overflow;
1536 * Force seeking to any (also non key) frames.
1537 * - encoding: unused
1538 * - decoding: Set by user
1543 * Flush the I/O context after each packet.
1544 * - encoding: Set by user
1545 * - decoding: unused
1550 * format probing score.
1551 * The maximal score is AVPROBE_SCORE_MAX, its set when the demuxer probes
1553 * - encoding: unused
1554 * - decoding: set by avformat, read by user
1559 * number of bytes to read maximally to identify format.
1560 * - encoding: unused
1561 * - decoding: set by user
1563 int format_probesize;
1566 * ',' separated list of allowed decoders.
1567 * If NULL then all are allowed
1568 * - encoding: unused
1569 * - decoding: set by user
1571 char *codec_whitelist;
1574 * ',' separated list of allowed demuxers.
1575 * If NULL then all are allowed
1576 * - encoding: unused
1577 * - decoding: set by user
1579 char *format_whitelist;
1582 * An opaque field for libavformat internal usage.
1583 * Must not be accessed in any way by callers.
1585 AVFormatInternal *internal;
1588 * IO repositioned flag.
1589 * This is set by avformat when the underlaying IO context read pointer
1590 * is repositioned, for example when doing byte based seeking.
1591 * Demuxers can use the flag to detect such changes.
1593 int io_repositioned;
1596 * Forced video codec.
1597 * This allows forcing a specific decoder, even when there are multiple with
1598 * the same codec_id.
1599 * Demuxing: Set by user
1601 const AVCodec *video_codec;
1604 * Forced audio codec.
1605 * This allows forcing a specific decoder, even when there are multiple with
1606 * the same codec_id.
1607 * Demuxing: Set by user
1609 const AVCodec *audio_codec;
1612 * Forced subtitle codec.
1613 * This allows forcing a specific decoder, even when there are multiple with
1614 * the same codec_id.
1615 * Demuxing: Set by user
1617 const AVCodec *subtitle_codec;
1620 * Forced data codec.
1621 * This allows forcing a specific decoder, even when there are multiple with
1622 * the same codec_id.
1623 * Demuxing: Set by user
1625 const AVCodec *data_codec;
1628 * Number of bytes to be written as padding in a metadata header.
1630 * Muxing: Set by user via av_format_set_metadata_header_padding.
1632 int metadata_header_padding;
1636 * This is a place for some private data of the user.
1641 * Callback used by devices to communicate with application.
1643 av_format_control_message control_message_cb;
1646 * Output timestamp offset, in microseconds.
1647 * Muxing: set by user
1649 int64_t output_ts_offset;
1652 * dump format separator.
1653 * can be ", " or "\n " or anything else
1654 * - muxing: Set by user.
1655 * - demuxing: Set by user.
1657 uint8_t *dump_separator;
1660 * Forced Data codec_id.
1661 * Demuxing: Set by user.
1663 enum AVCodecID data_codec_id;
1666 * ',' separated list of allowed protocols.
1667 * - encoding: unused
1668 * - decoding: set by user
1670 char *protocol_whitelist;
1673 * A callback for opening new IO streams.
1675 * Whenever a muxer or a demuxer needs to open an IO stream (typically from
1676 * avformat_open_input() for demuxers, but for certain formats can happen at
1677 * other times as well), it will call this callback to obtain an IO context.
1679 * @param s the format context
1680 * @param pb on success, the newly opened IO context should be returned here
1681 * @param url the url to open
1682 * @param flags a combination of AVIO_FLAG_*
1683 * @param options a dictionary of additional options, with the same
1684 * semantics as in avio_open2()
1685 * @return 0 on success, a negative AVERROR code on failure
1687 * @note Certain muxers and demuxers do nesting, i.e. they open one or more
1688 * additional internal format contexts. Thus the AVFormatContext pointer
1689 * passed to this callback may be different from the one facing the caller.
1690 * It will, however, have the same 'opaque' field.
1692 int (*io_open)(struct AVFormatContext *s, AVIOContext **pb, const char *url,
1693 int flags, AVDictionary **options);
1696 * A callback for closing the streams opened with AVFormatContext.io_open().
1698 void (*io_close)(struct AVFormatContext *s, AVIOContext *pb);
1701 * ',' separated list of disallowed protocols.
1702 * - encoding: unused
1703 * - decoding: set by user
1705 char *protocol_blacklist;
1708 * The maximum number of streams.
1709 * - encoding: unused
1710 * - decoding: set by user
1715 * Skip duration calcuation in estimate_timings_from_pts.
1716 * - encoding: unused
1717 * - decoding: set by user
1719 int skip_estimate_duration_from_pts;
1722 * Maximum number of packets that can be probed
1723 * - encoding: unused
1724 * - decoding: set by user
1726 int max_probe_packets;
1730 * This function will cause global side data to be injected in the next packet
1731 * of each stream as well as after any subsequent seek.
1733 void av_format_inject_global_side_data(AVFormatContext *s);
1736 * Returns the method used to set ctx->duration.
1738 * @return AVFMT_DURATION_FROM_PTS, AVFMT_DURATION_FROM_STREAM, or AVFMT_DURATION_FROM_BITRATE.
1740 enum AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext* ctx);
1743 * @defgroup lavf_core Core functions
1746 * Functions for querying libavformat capabilities, allocating core structures,
1752 * Return the LIBAVFORMAT_VERSION_INT constant.
1754 unsigned avformat_version(void);
1757 * Return the libavformat build-time configuration.
1759 const char *avformat_configuration(void);
1762 * Return the libavformat license.
1764 const char *avformat_license(void);
1767 * Do global initialization of network libraries. This is optional,
1768 * and not recommended anymore.
1770 * This functions only exists to work around thread-safety issues
1771 * with older GnuTLS or OpenSSL libraries. If libavformat is linked
1772 * to newer versions of those libraries, or if you do not use them,
1773 * calling this function is unnecessary. Otherwise, you need to call
1774 * this function before any other threads using them are started.
1776 * This function will be deprecated once support for older GnuTLS and
1777 * OpenSSL libraries is removed, and this function has no purpose
1780 int avformat_network_init(void);
1783 * Undo the initialization done by avformat_network_init. Call it only
1784 * once for each time you called avformat_network_init.
1786 int avformat_network_deinit(void);
1789 * Iterate over all registered muxers.
1791 * @param opaque a pointer where libavformat will store the iteration state. Must
1792 * point to NULL to start the iteration.
1794 * @return the next registered muxer or NULL when the iteration is
1797 const AVOutputFormat *av_muxer_iterate(void **opaque);
1800 * Iterate over all registered demuxers.
1802 * @param opaque a pointer where libavformat will store the iteration state. Must
1803 * point to NULL to start the iteration.
1805 * @return the next registered demuxer or NULL when the iteration is
1808 const AVInputFormat *av_demuxer_iterate(void **opaque);
1811 * Allocate an AVFormatContext.
1812 * avformat_free_context() can be used to free the context and everything
1813 * allocated by the framework within it.
1815 AVFormatContext *avformat_alloc_context(void);
1818 * Free an AVFormatContext and all its streams.
1819 * @param s context to free
1821 void avformat_free_context(AVFormatContext *s);
1824 * Get the AVClass for AVFormatContext. It can be used in combination with
1825 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
1827 * @see av_opt_find().
1829 const AVClass *avformat_get_class(void);
1832 * Add a new stream to a media file.
1834 * When demuxing, it is called by the demuxer in read_header(). If the
1835 * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
1836 * be called in read_packet().
1838 * When muxing, should be called by the user before avformat_write_header().
1840 * User is required to call avcodec_close() and avformat_free_context() to
1841 * clean up the allocation by avformat_new_stream().
1843 * @param s media file handle
1844 * @param c If non-NULL, the AVCodecContext corresponding to the new stream
1845 * will be initialized to use this codec. This is needed for e.g. codec-specific
1846 * defaults to be set, so codec should be provided if it is known.
1848 * @return newly created stream or NULL on error.
1850 AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c);
1853 * Wrap an existing array as stream side data.
1856 * @param type side information type
1857 * @param data the side data array. It must be allocated with the av_malloc()
1858 * family of functions. The ownership of the data is transferred to
1860 * @param size side information size
1861 * @return zero on success, a negative AVERROR code on failure. On failure,
1862 * the stream is unchanged and the data remains owned by the caller.
1864 int av_stream_add_side_data(AVStream *st, enum AVPacketSideDataType type,
1865 uint8_t *data, size_t size);
1868 * Allocate new information from stream.
1870 * @param stream stream
1871 * @param type desired side information type
1872 * @param size side information size
1873 * @return pointer to fresh allocated data or NULL otherwise
1875 uint8_t *av_stream_new_side_data(AVStream *stream,
1876 enum AVPacketSideDataType type, size_t size);
1878 * Get side information from stream.
1880 * @param stream stream
1881 * @param type desired side information type
1882 * @param size If supplied, *size will be set to the size of the side data
1883 * or to zero if the desired side data is not present.
1884 * @return pointer to data if present or NULL otherwise
1886 uint8_t *av_stream_get_side_data(const AVStream *stream,
1887 enum AVPacketSideDataType type, size_t *size);
1889 AVProgram *av_new_program(AVFormatContext *s, int id);
1897 * Allocate an AVFormatContext for an output format.
1898 * avformat_free_context() can be used to free the context and
1899 * everything allocated by the framework within it.
1901 * @param *ctx is set to the created format context, or to NULL in
1903 * @param oformat format to use for allocating the context, if NULL
1904 * format_name and filename are used instead
1905 * @param format_name the name of output format to use for allocating the
1906 * context, if NULL filename is used instead
1907 * @param filename the name of the filename to use for allocating the
1908 * context, may be NULL
1909 * @return >= 0 in case of success, a negative AVERROR code in case of
1912 int avformat_alloc_output_context2(AVFormatContext **ctx, const AVOutputFormat *oformat,
1913 const char *format_name, const char *filename);
1916 * @addtogroup lavf_decoding
1921 * Find AVInputFormat based on the short name of the input format.
1923 const AVInputFormat *av_find_input_format(const char *short_name);
1926 * Guess the file format.
1928 * @param pd data to be probed
1929 * @param is_opened Whether the file is already opened; determines whether
1930 * demuxers with or without AVFMT_NOFILE are probed.
1932 const AVInputFormat *av_probe_input_format(const AVProbeData *pd, int is_opened);
1935 * Guess the file format.
1937 * @param pd data to be probed
1938 * @param is_opened Whether the file is already opened; determines whether
1939 * demuxers with or without AVFMT_NOFILE are probed.
1940 * @param score_max A probe score larger that this is required to accept a
1941 * detection, the variable is set to the actual detection
1943 * If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
1944 * to retry with a larger probe buffer.
1946 const AVInputFormat *av_probe_input_format2(const AVProbeData *pd,
1947 int is_opened, int *score_max);
1950 * Guess the file format.
1952 * @param is_opened Whether the file is already opened; determines whether
1953 * demuxers with or without AVFMT_NOFILE are probed.
1954 * @param score_ret The score of the best detection.
1956 const AVInputFormat *av_probe_input_format3(const AVProbeData *pd,
1957 int is_opened, int *score_ret);
1960 * Probe a bytestream to determine the input format. Each time a probe returns
1961 * with a score that is too low, the probe buffer size is increased and another
1962 * attempt is made. When the maximum probe size is reached, the input format
1963 * with the highest score is returned.
1965 * @param pb the bytestream to probe
1966 * @param fmt the input format is put here
1967 * @param url the url of the stream
1968 * @param logctx the log context
1969 * @param offset the offset within the bytestream to probe from
1970 * @param max_probe_size the maximum probe buffer size (zero for default)
1971 * @return the score in case of success, a negative value corresponding to an
1972 * the maximal score is AVPROBE_SCORE_MAX
1973 * AVERROR code otherwise
1975 int av_probe_input_buffer2(AVIOContext *pb, const AVInputFormat **fmt,
1976 const char *url, void *logctx,
1977 unsigned int offset, unsigned int max_probe_size);
1980 * Like av_probe_input_buffer2() but returns 0 on success
1982 int av_probe_input_buffer(AVIOContext *pb, const AVInputFormat **fmt,
1983 const char *url, void *logctx,
1984 unsigned int offset, unsigned int max_probe_size);
1987 * Open an input stream and read the header. The codecs are not opened.
1988 * The stream must be closed with avformat_close_input().
1990 * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
1991 * May be a pointer to NULL, in which case an AVFormatContext is allocated by this
1992 * function and written into ps.
1993 * Note that a user-supplied AVFormatContext will be freed on failure.
1994 * @param url URL of the stream to open.
1995 * @param fmt If non-NULL, this parameter forces a specific input format.
1996 * Otherwise the format is autodetected.
1997 * @param options A dictionary filled with AVFormatContext and demuxer-private options.
1998 * On return this parameter will be destroyed and replaced with a dict containing
1999 * options that were not found. May be NULL.
2001 * @return 0 on success, a negative AVERROR on failure.
2003 * @note If you want to use custom IO, preallocate the format context and set its pb field.
2005 int avformat_open_input(AVFormatContext **ps, const char *url,
2006 const AVInputFormat *fmt, AVDictionary **options);
2009 * Read packets of a media file to get stream information. This
2010 * is useful for file formats with no headers such as MPEG. This
2011 * function also computes the real framerate in case of MPEG-2 repeat
2013 * The logical file position is not changed by this function;
2014 * examined packets may be buffered for later processing.
2016 * @param ic media file handle
2017 * @param options If non-NULL, an ic.nb_streams long array of pointers to
2018 * dictionaries, where i-th member contains options for
2019 * codec corresponding to i-th stream.
2020 * On return each dictionary will be filled with options that were not found.
2021 * @return >=0 if OK, AVERROR_xxx on error
2023 * @note this function isn't guaranteed to open all the codecs, so
2024 * options being non-empty at return is a perfectly normal behavior.
2026 * @todo Let the user decide somehow what information is needed so that
2027 * we do not waste time getting stuff the user does not need.
2029 int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options);
2032 * Find the programs which belong to a given stream.
2034 * @param ic media file handle
2035 * @param last the last found program, the search will start after this
2036 * program, or from the beginning if it is NULL
2037 * @param s stream index
2038 * @return the next program which belongs to s, NULL if no program is found or
2039 * the last program is not among the programs of ic.
2041 AVProgram *av_find_program_from_stream(AVFormatContext *ic, AVProgram *last, int s);
2043 void av_program_add_stream_index(AVFormatContext *ac, int progid, unsigned int idx);
2046 * Find the "best" stream in the file.
2047 * The best stream is determined according to various heuristics as the most
2048 * likely to be what the user expects.
2049 * If the decoder parameter is non-NULL, av_find_best_stream will find the
2050 * default decoder for the stream's codec; streams for which no decoder can
2051 * be found are ignored.
2053 * @param ic media file handle
2054 * @param type stream type: video, audio, subtitles, etc.
2055 * @param wanted_stream_nb user-requested stream number,
2056 * or -1 for automatic selection
2057 * @param related_stream try to find a stream related (eg. in the same
2058 * program) to this one, or -1 if none
2059 * @param decoder_ret if non-NULL, returns the decoder for the
2061 * @param flags flags; none are currently defined
2062 * @return the non-negative stream number in case of success,
2063 * AVERROR_STREAM_NOT_FOUND if no stream with the requested type
2065 * AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
2066 * @note If av_find_best_stream returns successfully and decoder_ret is not
2067 * NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
2069 int av_find_best_stream(AVFormatContext *ic,
2070 enum AVMediaType type,
2071 int wanted_stream_nb,
2073 AVCodec **decoder_ret,
2077 * Return the next frame of a stream.
2078 * This function returns what is stored in the file, and does not validate
2079 * that what is there are valid frames for the decoder. It will split what is
2080 * stored in the file into frames and return one for each call. It will not
2081 * omit invalid data between valid frames so as to give the decoder the maximum
2082 * information possible for decoding.
2084 * On success, the returned packet is reference-counted (pkt->buf is set) and
2085 * valid indefinitely. The packet must be freed with av_packet_unref() when
2086 * it is no longer needed. For video, the packet contains exactly one frame.
2087 * For audio, it contains an integer number of frames if each frame has
2088 * a known fixed size (e.g. PCM or ADPCM data). If the audio frames have
2089 * a variable size (e.g. MPEG audio), then it contains one frame.
2091 * pkt->pts, pkt->dts and pkt->duration are always set to correct
2092 * values in AVStream.time_base units (and guessed if the format cannot
2093 * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
2094 * has B-frames, so it is better to rely on pkt->dts if you do not
2095 * decompress the payload.
2097 * @return 0 if OK, < 0 on error or end of file. On error, pkt will be blank
2098 * (as if it came from av_packet_alloc()).
2100 * @note pkt will be initialized, so it may be uninitialized, but it must not
2101 * contain data that needs to be freed.
2103 int av_read_frame(AVFormatContext *s, AVPacket *pkt);
2106 * Seek to the keyframe at timestamp.
2107 * 'timestamp' in 'stream_index'.
2109 * @param s media file handle
2110 * @param stream_index If stream_index is (-1), a default
2111 * stream is selected, and timestamp is automatically converted
2112 * from AV_TIME_BASE units to the stream specific time_base.
2113 * @param timestamp Timestamp in AVStream.time_base units
2114 * or, if no stream is specified, in AV_TIME_BASE units.
2115 * @param flags flags which select direction and seeking mode
2116 * @return >= 0 on success
2118 int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
2122 * Seek to timestamp ts.
2123 * Seeking will be done so that the point from which all active streams
2124 * can be presented successfully will be closest to ts and within min/max_ts.
2125 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
2127 * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
2128 * are the file position (this may not be supported by all demuxers).
2129 * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
2130 * in the stream with stream_index (this may not be supported by all demuxers).
2131 * Otherwise all timestamps are in units of the stream selected by stream_index
2132 * or if stream_index is -1, in AV_TIME_BASE units.
2133 * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
2134 * keyframes (this may not be supported by all demuxers).
2135 * If flags contain AVSEEK_FLAG_BACKWARD, it is ignored.
2137 * @param s media file handle
2138 * @param stream_index index of the stream which is used as time base reference
2139 * @param min_ts smallest acceptable timestamp
2140 * @param ts target timestamp
2141 * @param max_ts largest acceptable timestamp
2142 * @param flags flags
2143 * @return >=0 on success, error code otherwise
2145 * @note This is part of the new seek API which is still under construction.
2147 int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
2150 * Discard all internally buffered data. This can be useful when dealing with
2151 * discontinuities in the byte stream. Generally works only with formats that
2152 * can resync. This includes headerless formats like MPEG-TS/TS but should also
2153 * work with NUT, Ogg and in a limited way AVI for example.
2155 * The set of streams, the detected duration, stream parameters and codecs do
2156 * not change when calling this function. If you want a complete reset, it's
2157 * better to open a new AVFormatContext.
2159 * This does not flush the AVIOContext (s->pb). If necessary, call
2160 * avio_flush(s->pb) before calling this function.
2162 * @param s media file handle
2163 * @return >=0 on success, error code otherwise
2165 int avformat_flush(AVFormatContext *s);
2168 * Start playing a network-based stream (e.g. RTSP stream) at the
2171 int av_read_play(AVFormatContext *s);
2174 * Pause a network-based stream (e.g. RTSP stream).
2176 * Use av_read_play() to resume it.
2178 int av_read_pause(AVFormatContext *s);
2181 * Close an opened input AVFormatContext. Free it and all its contents
2182 * and set *s to NULL.
2184 void avformat_close_input(AVFormatContext **s);
2189 #define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
2190 #define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
2191 #define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
2192 #define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
2195 * @addtogroup lavf_encoding
2199 #define AVSTREAM_INIT_IN_WRITE_HEADER 0 ///< stream parameters initialized in avformat_write_header
2200 #define AVSTREAM_INIT_IN_INIT_OUTPUT 1 ///< stream parameters initialized in avformat_init_output
2203 * Allocate the stream private data and write the stream header to
2204 * an output media file.
2206 * @param s Media file handle, must be allocated with avformat_alloc_context().
2207 * Its oformat field must be set to the desired output format;
2208 * Its pb field must be set to an already opened AVIOContext.
2209 * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
2210 * On return this parameter will be destroyed and replaced with a dict containing
2211 * options that were not found. May be NULL.
2213 * @return AVSTREAM_INIT_IN_WRITE_HEADER on success if the codec had not already been fully initialized in avformat_init,
2214 * AVSTREAM_INIT_IN_INIT_OUTPUT on success if the codec had already been fully initialized in avformat_init,
2215 * negative AVERROR on failure.
2217 * @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_init_output.
2219 av_warn_unused_result
2220 int avformat_write_header(AVFormatContext *s, AVDictionary **options);
2223 * Allocate the stream private data and initialize the codec, but do not write the header.
2224 * May optionally be used before avformat_write_header to initialize stream parameters
2225 * before actually writing the header.
2226 * If using this function, do not pass the same options to avformat_write_header.
2228 * @param s Media file handle, must be allocated with avformat_alloc_context().
2229 * Its oformat field must be set to the desired output format;
2230 * Its pb field must be set to an already opened AVIOContext.
2231 * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
2232 * On return this parameter will be destroyed and replaced with a dict containing
2233 * options that were not found. May be NULL.
2235 * @return AVSTREAM_INIT_IN_WRITE_HEADER on success if the codec requires avformat_write_header to fully initialize,
2236 * AVSTREAM_INIT_IN_INIT_OUTPUT on success if the codec has been fully initialized,
2237 * negative AVERROR on failure.
2239 * @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_write_header.
2241 av_warn_unused_result
2242 int avformat_init_output(AVFormatContext *s, AVDictionary **options);
2245 * Write a packet to an output media file.
2247 * This function passes the packet directly to the muxer, without any buffering
2248 * or reordering. The caller is responsible for correctly interleaving the
2249 * packets if the format requires it. Callers that want libavformat to handle
2250 * the interleaving should call av_interleaved_write_frame() instead of this
2253 * @param s media file handle
2254 * @param pkt The packet containing the data to be written. Note that unlike
2255 * av_interleaved_write_frame(), this function does not take
2256 * ownership of the packet passed to it (though some muxers may make
2257 * an internal reference to the input packet).
2259 * This parameter can be NULL (at any time, not just at the end), in
2260 * order to immediately flush data buffered within the muxer, for
2261 * muxers that buffer up data internally before writing it to the
2264 * Packet's @ref AVPacket.stream_index "stream_index" field must be
2265 * set to the index of the corresponding stream in @ref
2266 * AVFormatContext.streams "s->streams".
2268 * The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2269 * must be set to correct values in the stream's timebase (unless the
2270 * output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2271 * they can be set to AV_NOPTS_VALUE).
2272 * The dts for subsequent packets passed to this function must be strictly
2273 * increasing when compared in their respective timebases (unless the
2274 * output format is flagged with the AVFMT_TS_NONSTRICT, then they
2275 * merely have to be nondecreasing). @ref AVPacket.duration
2276 * "duration") should also be set if known.
2277 * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
2279 * @see av_interleaved_write_frame()
2281 int av_write_frame(AVFormatContext *s, AVPacket *pkt);
2284 * Write a packet to an output media file ensuring correct interleaving.
2286 * This function will buffer the packets internally as needed to make sure the
2287 * packets in the output file are properly interleaved in the order of
2288 * increasing dts. Callers doing their own interleaving should call
2289 * av_write_frame() instead of this function.
2291 * Using this function instead of av_write_frame() can give muxers advance
2292 * knowledge of future packets, improving e.g. the behaviour of the mp4
2293 * muxer for VFR content in fragmenting mode.
2295 * @param s media file handle
2296 * @param pkt The packet containing the data to be written.
2298 * If the packet is reference-counted, this function will take
2299 * ownership of this reference and unreference it later when it sees
2301 * The caller must not access the data through this reference after
2302 * this function returns. If the packet is not reference-counted,
2303 * libavformat will make a copy.
2305 * This parameter can be NULL (at any time, not just at the end), to
2306 * flush the interleaving queues.
2308 * Packet's @ref AVPacket.stream_index "stream_index" field must be
2309 * set to the index of the corresponding stream in @ref
2310 * AVFormatContext.streams "s->streams".
2312 * The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
2313 * must be set to correct values in the stream's timebase (unless the
2314 * output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
2315 * they can be set to AV_NOPTS_VALUE).
2316 * The dts for subsequent packets in one stream must be strictly
2317 * increasing (unless the output format is flagged with the
2318 * AVFMT_TS_NONSTRICT, then they merely have to be nondecreasing).
2319 * @ref AVPacket.duration "duration") should also be set if known.
2321 * @return 0 on success, a negative AVERROR on error. Libavformat will always
2322 * take care of freeing the packet, even if this function fails.
2324 * @see av_write_frame(), AVFormatContext.max_interleave_delta
2326 int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
2329 * Write an uncoded frame to an output media file.
2331 * The frame must be correctly interleaved according to the container
2332 * specification; if not, av_interleaved_write_uncoded_frame() must be used.
2334 * See av_interleaved_write_uncoded_frame() for details.
2336 int av_write_uncoded_frame(AVFormatContext *s, int stream_index,
2340 * Write an uncoded frame to an output media file.
2342 * If the muxer supports it, this function makes it possible to write an AVFrame
2343 * structure directly, without encoding it into a packet.
2344 * It is mostly useful for devices and similar special muxers that use raw
2345 * video or PCM data and will not serialize it into a byte stream.
2347 * To test whether it is possible to use it with a given muxer and stream,
2348 * use av_write_uncoded_frame_query().
2350 * The caller gives up ownership of the frame and must not access it
2353 * @return >=0 for success, a negative code on error
2355 int av_interleaved_write_uncoded_frame(AVFormatContext *s, int stream_index,
2359 * Test whether a muxer supports uncoded frame.
2361 * @return >=0 if an uncoded frame can be written to that muxer and stream,
2364 int av_write_uncoded_frame_query(AVFormatContext *s, int stream_index);
2367 * Write the stream trailer to an output media file and free the
2368 * file private data.
2370 * May only be called after a successful call to avformat_write_header.
2372 * @param s media file handle
2373 * @return 0 if OK, AVERROR_xxx on error
2375 int av_write_trailer(AVFormatContext *s);
2378 * Return the output format in the list of registered output formats
2379 * which best matches the provided parameters, or return NULL if
2380 * there is no match.
2382 * @param short_name if non-NULL checks if short_name matches with the
2383 * names of the registered formats
2384 * @param filename if non-NULL checks if filename terminates with the
2385 * extensions of the registered formats
2386 * @param mime_type if non-NULL checks if mime_type matches with the
2387 * MIME type of the registered formats
2389 const AVOutputFormat *av_guess_format(const char *short_name,
2390 const char *filename,
2391 const char *mime_type);
2394 * Guess the codec ID based upon muxer and filename.
2396 enum AVCodecID av_guess_codec(const AVOutputFormat *fmt, const char *short_name,
2397 const char *filename, const char *mime_type,
2398 enum AVMediaType type);
2401 * Get timing information for the data currently output.
2402 * The exact meaning of "currently output" depends on the format.
2403 * It is mostly relevant for devices that have an internal buffer and/or
2404 * work in real time.
2405 * @param s media file handle
2406 * @param stream stream in the media file
2407 * @param[out] dts DTS of the last packet output for the stream, in stream
2409 * @param[out] wall absolute time when that packet whas output,
2411 * @return 0 if OK, AVERROR(ENOSYS) if the format does not support it
2412 * Note: some formats or devices may not allow to measure dts and wall
2415 int av_get_output_timestamp(struct AVFormatContext *s, int stream,
2416 int64_t *dts, int64_t *wall);
2425 * @defgroup lavf_misc Utility functions
2429 * Miscellaneous utility functions related to both muxing and demuxing
2434 * Send a nice hexadecimal dump of a buffer to the specified file stream.
2436 * @param f The file stream pointer where the dump should be sent to.
2438 * @param size buffer size
2440 * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
2442 void av_hex_dump(FILE *f, const uint8_t *buf, int size);
2445 * Send a nice hexadecimal dump of a buffer to the log.
2447 * @param avcl A pointer to an arbitrary struct of which the first field is a
2448 * pointer to an AVClass struct.
2449 * @param level The importance level of the message, lower values signifying
2450 * higher importance.
2452 * @param size buffer size
2454 * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
2456 void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
2459 * Send a nice dump of a packet to the specified file stream.
2461 * @param f The file stream pointer where the dump should be sent to.
2462 * @param pkt packet to dump
2463 * @param dump_payload True if the payload must be displayed, too.
2464 * @param st AVStream that the packet belongs to
2466 void av_pkt_dump2(FILE *f, const AVPacket *pkt, int dump_payload, const AVStream *st);
2470 * Send a nice dump of a packet to the log.
2472 * @param avcl A pointer to an arbitrary struct of which the first field is a
2473 * pointer to an AVClass struct.
2474 * @param level The importance level of the message, lower values signifying
2475 * higher importance.
2476 * @param pkt packet to dump
2477 * @param dump_payload True if the payload must be displayed, too.
2478 * @param st AVStream that the packet belongs to
2480 void av_pkt_dump_log2(void *avcl, int level, const AVPacket *pkt, int dump_payload,
2481 const AVStream *st);
2484 * Get the AVCodecID for the given codec tag tag.
2485 * If no codec id is found returns AV_CODEC_ID_NONE.
2487 * @param tags list of supported codec_id-codec_tag pairs, as stored
2488 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2489 * @param tag codec tag to match to a codec ID
2491 enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
2494 * Get the codec tag for the given codec id id.
2495 * If no codec tag is found returns 0.
2497 * @param tags list of supported codec_id-codec_tag pairs, as stored
2498 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2499 * @param id codec ID to match to a codec tag
2501 unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id);
2504 * Get the codec tag for the given codec id.
2506 * @param tags list of supported codec_id - codec_tag pairs, as stored
2507 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2508 * @param id codec id that should be searched for in the list
2509 * @param tag A pointer to the found tag
2510 * @return 0 if id was not found in tags, > 0 if it was found
2512 int av_codec_get_tag2(const struct AVCodecTag * const *tags, enum AVCodecID id,
2515 int av_find_default_stream_index(AVFormatContext *s);
2518 * Get the index for a specific timestamp.
2520 * @param st stream that the timestamp belongs to
2521 * @param timestamp timestamp to retrieve the index for
2522 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
2523 * to the timestamp which is <= the requested one, if backward
2524 * is 0, then it will be >=
2525 * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
2526 * @return < 0 if no such timestamp could be found
2528 int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
2531 * Get the index entry count for the given AVStream.
2534 * @return the number of index entries in the stream
2536 int avformat_index_get_entries_count(const AVStream *st);
2539 * Get the AVIndexEntry corresponding to the given index.
2541 * @param st Stream containing the requested AVIndexEntry.
2542 * @param idx The desired index.
2543 * @return A pointer to the requested AVIndexEntry if it exists, NULL otherwise.
2545 * @note The pointer returned by this function is only guaranteed to be valid
2546 * until any function that could alter the stream or the AVFormatContext
2547 * that contains it is called.
2549 const AVIndexEntry *avformat_index_get_entry(const AVStream *st, int idx);
2552 * Get the AVIndexEntry corresponding to the given timestamp.
2554 * @param st Stream containing the requested AVIndexEntry.
2555 * @param timestamp Timestamp to retrieve the index entry for.
2556 * @param flags If AVSEEK_FLAG_BACKWARD then the returned entry will correspond
2557 * to the timestamp which is <= the requested one, if backward
2558 * is 0, then it will be >=
2559 * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise.
2560 * @return A pointer to the requested AVIndexEntry if it exists, NULL otherwise.
2562 * @note The pointer returned by this function is only guaranteed to be valid
2563 * until any function that could alter the stream or the AVFormatContext
2564 * that contains it is called.
2566 const AVIndexEntry *avformat_index_get_entry_from_timestamp(const AVStream *st,
2567 int64_t wanted_timestamp,
2570 * Add an index entry into a sorted list. Update the entry if the list
2571 * already contains it.
2573 * @param timestamp timestamp in the time base of the given stream
2575 int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
2576 int size, int distance, int flags);
2580 * Split a URL string into components.
2582 * The pointers to buffers for storing individual components may be null,
2583 * in order to ignore that component. Buffers for components not found are
2584 * set to empty strings. If the port is not found, it is set to a negative
2587 * @param proto the buffer for the protocol
2588 * @param proto_size the size of the proto buffer
2589 * @param authorization the buffer for the authorization
2590 * @param authorization_size the size of the authorization buffer
2591 * @param hostname the buffer for the host name
2592 * @param hostname_size the size of the hostname buffer
2593 * @param port_ptr a pointer to store the port number in
2594 * @param path the buffer for the path
2595 * @param path_size the size of the path buffer
2596 * @param url the URL to split
2598 void av_url_split(char *proto, int proto_size,
2599 char *authorization, int authorization_size,
2600 char *hostname, int hostname_size,
2602 char *path, int path_size,
2607 * Print detailed information about the input or output format, such as
2608 * duration, bitrate, streams, container, programs, metadata, side data,
2609 * codec and time base.
2611 * @param ic the context to analyze
2612 * @param index index of the stream to dump information about
2613 * @param url the URL to print, such as source or destination file
2614 * @param is_output Select whether the specified context is an input(0) or output(1)
2616 void av_dump_format(AVFormatContext *ic,
2622 #define AV_FRAME_FILENAME_FLAGS_MULTIPLE 1 ///< Allow multiple %d
2625 * Return in 'buf' the path with '%d' replaced by a number.
2627 * Also handles the '%0nd' format where 'n' is the total number
2628 * of digits and '%%'.
2630 * @param buf destination buffer
2631 * @param buf_size destination buffer size
2632 * @param path numbered sequence string
2633 * @param number frame number
2634 * @param flags AV_FRAME_FILENAME_FLAGS_*
2635 * @return 0 if OK, -1 on format error
2637 int av_get_frame_filename2(char *buf, int buf_size,
2638 const char *path, int number, int flags);
2640 int av_get_frame_filename(char *buf, int buf_size,
2641 const char *path, int number);
2644 * Check whether filename actually is a numbered sequence generator.
2646 * @param filename possible numbered sequence string
2647 * @return 1 if a valid numbered sequence string, 0 otherwise
2649 int av_filename_number_test(const char *filename);
2652 * Generate an SDP for an RTP session.
2654 * Note, this overwrites the id values of AVStreams in the muxer contexts
2655 * for getting unique dynamic payload types.
2657 * @param ac array of AVFormatContexts describing the RTP streams. If the
2658 * array is composed by only one context, such context can contain
2659 * multiple AVStreams (one AVStream per RTP stream). Otherwise,
2660 * all the contexts in the array (an AVCodecContext per RTP stream)
2661 * must contain only one AVStream.
2662 * @param n_files number of AVCodecContexts contained in ac
2663 * @param buf buffer where the SDP will be stored (must be allocated by
2665 * @param size the size of the buffer
2666 * @return 0 if OK, AVERROR_xxx on error
2668 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
2671 * Return a positive value if the given filename has one of the given
2672 * extensions, 0 otherwise.
2674 * @param filename file name to check against the given extensions
2675 * @param extensions a comma-separated list of filename extensions
2677 int av_match_ext(const char *filename, const char *extensions);
2680 * Test if the given container can store a codec.
2682 * @param ofmt container to check for compatibility
2683 * @param codec_id codec to potentially store in container
2684 * @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
2686 * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
2687 * A negative number if this information is not available.
2689 int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id,
2690 int std_compliance);
2693 * @defgroup riff_fourcc RIFF FourCCs
2695 * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
2696 * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
2699 * uint32_t tag = MKTAG('H', '2', '6', '4');
2700 * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
2701 * enum AVCodecID id = av_codec_get_id(table, tag);
2705 * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
2707 const struct AVCodecTag *avformat_get_riff_video_tags(void);
2709 * @return the table mapping RIFF FourCCs for audio to AVCodecID.
2711 const struct AVCodecTag *avformat_get_riff_audio_tags(void);
2713 * @return the table mapping MOV FourCCs for video to libavcodec AVCodecID.
2715 const struct AVCodecTag *avformat_get_mov_video_tags(void);
2717 * @return the table mapping MOV FourCCs for audio to AVCodecID.
2719 const struct AVCodecTag *avformat_get_mov_audio_tags(void);
2726 * Guess the sample aspect ratio of a frame, based on both the stream and the
2727 * frame aspect ratio.
2729 * Since the frame aspect ratio is set by the codec but the stream aspect ratio
2730 * is set by the demuxer, these two may not be equal. This function tries to
2731 * return the value that you should use if you would like to display the frame.
2733 * Basic logic is to use the stream aspect ratio if it is set to something sane
2734 * otherwise use the frame aspect ratio. This way a container setting, which is
2735 * usually easy to modify can override the coded value in the frames.
2737 * @param format the format context which the stream is part of
2738 * @param stream the stream which the frame is part of
2739 * @param frame the frame with the aspect ratio to be determined
2740 * @return the guessed (valid) sample_aspect_ratio, 0/1 if no idea
2742 AVRational av_guess_sample_aspect_ratio(AVFormatContext *format, AVStream *stream, AVFrame *frame);
2745 * Guess the frame rate, based on both the container and codec information.
2747 * @param ctx the format context which the stream is part of
2748 * @param stream the stream which the frame is part of
2749 * @param frame the frame for which the frame rate should be determined, may be NULL
2750 * @return the guessed (valid) frame rate, 0/1 if no idea
2752 AVRational av_guess_frame_rate(AVFormatContext *ctx, AVStream *stream, AVFrame *frame);
2755 * Check if the stream st contained in s is matched by the stream specifier
2758 * See the "stream specifiers" chapter in the documentation for the syntax
2761 * @return >0 if st is matched by spec;
2762 * 0 if st is not matched by spec;
2763 * AVERROR code if spec is invalid
2765 * @note A stream specifier can match several streams in the format.
2767 int avformat_match_stream_specifier(AVFormatContext *s, AVStream *st,
2770 int avformat_queue_attached_pictures(AVFormatContext *s);
2772 enum AVTimebaseSource {
2773 AVFMT_TBCF_AUTO = -1,
2776 #if FF_API_R_FRAME_RATE
2777 AVFMT_TBCF_R_FRAMERATE,
2782 * Transfer internal timing information from one stream to another.
2784 * This function is useful when doing stream copy.
2786 * @param ofmt target output format for ost
2787 * @param ost output stream which needs timings copy and adjustments
2788 * @param ist reference input stream to copy timings from
2789 * @param copy_tb define from where the stream codec timebase needs to be imported
2791 int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
2792 AVStream *ost, const AVStream *ist,
2793 enum AVTimebaseSource copy_tb);
2796 * Get the internal codec timebase from a stream.
2798 * @param st input stream to extract the timebase from
2800 AVRational av_stream_get_codec_timebase(const AVStream *st);
2806 #endif /* AVFORMAT_AVFORMAT_H */