2 * copyright (c) 2001 Fabrice Bellard
4 * This file is part of Libav.
6 * Libav 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 * Libav 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 Libav; 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 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). Before using lavf, you need to call
40 * av_register_all() to register all compiled muxers, demuxers and protocols.
41 * Unless you are absolutely sure you won't use libavformat's network
42 * capabilities, you should also call avformat_network_init().
44 * A supported input format is described by an AVInputFormat struct, conversely
45 * an output format is described by AVOutputFormat. You can iterate over all
46 * registered input/output formats using the av_iformat_next() /
47 * av_oformat_next() functions. The protocols layer is not part of the public
48 * API, so you can only get the names of supported protocols with the
49 * avio_enum_protocols() function.
51 * Main lavf structure used for both muxing and demuxing is AVFormatContext,
52 * which exports all information about the file being read or written. As with
53 * most Libav structures, its size is not part of public ABI, so it cannot be
54 * allocated on stack or directly with av_malloc(). To create an
55 * AVFormatContext, use avformat_alloc_context() (some functions, like
56 * avformat_open_input() might do that for you).
58 * Most importantly an AVFormatContext contains:
59 * @li the @ref AVFormatContext.iformat "input" or @ref AVFormatContext.oformat
60 * "output" format. It is either autodetected or set by user for input;
61 * always set by user for output.
62 * @li an @ref AVFormatContext.streams "array" of AVStreams, which describe all
63 * elementary streams stored in the file. AVStreams are typically referred to
64 * using their index in this array.
65 * @li an @ref AVFormatContext.pb "I/O context". It is either opened by lavf or
66 * set by user for input, always set by user for output (unless you are dealing
67 * with an AVFMT_NOFILE format).
69 * @section lavf_options Passing options to (de)muxers
70 * Lavf allows to configure muxers and demuxers using the @ref avoptions
71 * mechanism. Generic (format-independent) libavformat options are provided by
72 * AVFormatContext, they can be examined from a user program by calling
73 * av_opt_next() / av_opt_find() on an allocated AVFormatContext (or its AVClass
74 * from avformat_get_class()). Private (format-specific) options are provided by
75 * AVFormatContext.priv_data if and only if AVInputFormat.priv_class /
76 * AVOutputFormat.priv_class of the corresponding format struct is non-NULL.
77 * Further options may be provided by the @ref AVFormatContext.pb "I/O context",
78 * if its AVClass is non-NULL, and the protocols layer. See the discussion on
79 * nesting in @ref avoptions documentation to learn how to access those.
81 * @defgroup lavf_decoding Demuxing
83 * Demuxers read a media file and split it into chunks of data (@em packets). A
84 * @ref AVPacket "packet" contains one or more encoded frames which belongs to a
85 * single elementary stream. In the lavf API this process is represented by the
86 * avformat_open_input() function for opening a file, av_read_frame() for
87 * reading a single packet and finally avformat_close_input(), which does the
90 * @section lavf_decoding_open Opening a media file
91 * The minimum information required to open a file is its URL or filename, which
92 * is passed to avformat_open_input(), as in the following code:
94 * const char *url = "in.mp3";
95 * AVFormatContext *s = NULL;
96 * int ret = avformat_open_input(&s, url, NULL, NULL);
100 * The above code attempts to allocate an AVFormatContext, open the
101 * specified file (autodetecting the format) and read the header, exporting the
102 * information stored there into s. Some formats do not have a header or do not
103 * store enough information there, so it is recommended that you call the
104 * avformat_find_stream_info() function which tries to read and decode a few
105 * frames to find missing information.
107 * In some cases you might want to preallocate an AVFormatContext yourself with
108 * avformat_alloc_context() and do some tweaking on it before passing it to
109 * avformat_open_input(). One such case is when you want to use custom functions
110 * for reading input data instead of lavf internal I/O layer.
111 * To do that, create your own AVIOContext with avio_alloc_context(), passing
112 * your reading callbacks to it. Then set the @em pb field of your
113 * AVFormatContext to newly created AVIOContext.
115 * Since the format of the opened file is in general not known until after
116 * avformat_open_input() has returned, it is not possible to set demuxer private
117 * options on a preallocated context. Instead, the options should be passed to
118 * avformat_open_input() wrapped in an AVDictionary:
120 * AVDictionary *options = NULL;
121 * av_dict_set(&options, "video_size", "640x480", 0);
122 * av_dict_set(&options, "pixel_format", "rgb24", 0);
124 * if (avformat_open_input(&s, url, NULL, &options) < 0)
126 * av_dict_free(&options);
128 * This code passes the private options 'video_size' and 'pixel_format' to the
129 * demuxer. They would be necessary for e.g. the rawvideo demuxer, since it
130 * cannot know how to interpret raw video data otherwise. If the format turns
131 * out to be something different than raw video, those options will not be
132 * recognized by the demuxer and therefore will not be applied. Such unrecognized
133 * options are then returned in the options dictionary (recognized options are
134 * consumed). The calling program can handle such unrecognized options as it
137 * AVDictionaryEntry *e;
138 * if (e = av_dict_get(options, "", NULL, AV_DICT_IGNORE_SUFFIX)) {
139 * fprintf(stderr, "Option %s not recognized by the demuxer.\n", e->key);
144 * After you have finished reading the file, you must close it with
145 * avformat_close_input(). It will free everything associated with the file.
147 * @section lavf_decoding_read Reading from an opened file
148 * Reading data from an opened AVFormatContext is done by repeatedly calling
149 * av_read_frame() on it. Each call, if successful, will return an AVPacket
150 * containing encoded data for one AVStream, identified by
151 * AVPacket.stream_index. This packet may be passed straight into the libavcodec
152 * decoding functions avcodec_send_packet() or avcodec_decode_subtitle2() if the
153 * caller wishes to decode the data.
155 * AVPacket.pts, AVPacket.dts and AVPacket.duration timing information will be
156 * set if known. They may also be unset (i.e. AV_NOPTS_VALUE for
157 * pts/dts, 0 for duration) if the stream does not provide them. The timing
158 * information will be in AVStream.time_base units, i.e. it has to be
159 * multiplied by the timebase to convert them to seconds.
161 * If AVPacket.buf is set on the returned packet, then the packet is
162 * allocated dynamically and the user may keep it indefinitely.
163 * Otherwise, if AVPacket.buf is NULL, the packet data is backed by a
164 * static storage somewhere inside the demuxer and the packet is only valid
165 * until the next av_read_frame() call or closing the file. If the caller
166 * requires a longer lifetime, av_dup_packet() will make an av_malloc()ed copy
168 * In both cases, the packet must be freed with av_packet_unref() when it is no
171 * @section lavf_decoding_seek Seeking
174 * @defgroup lavf_encoding Muxing
176 * Muxers take encoded data in the form of @ref AVPacket "AVPackets" and write
177 * it into files or other output bytestreams in the specified container format.
179 * The main API functions for muxing are avformat_write_header() for writing the
180 * file header, av_write_frame() / av_interleaved_write_frame() for writing the
181 * packets and av_write_trailer() for finalizing the file.
183 * At the beginning of the muxing process, the caller must first call
184 * avformat_alloc_context() to create a muxing context. The caller then sets up
185 * the muxer by filling the various fields in this context:
187 * - The @ref AVFormatContext.oformat "oformat" field must be set to select the
188 * muxer that will be used.
189 * - Unless the format is of the AVFMT_NOFILE type, the @ref AVFormatContext.pb
190 * "pb" field must be set to an opened IO context, either returned from
191 * avio_open2() or a custom one.
192 * - Unless the format is of the AVFMT_NOSTREAMS type, at least one stream must
193 * be created with the avformat_new_stream() function. The caller should fill
194 * the @ref AVStream.codecpar "stream codec parameters" information, such as the
195 * codec @ref AVCodecParameters.codec_type "type", @ref AVCodecParameters.codec_id
196 * "id" and other parameters (e.g. width / height, the pixel or sample format,
197 * etc.) as known. The @ref AVStream.time_base "stream timebase" should
198 * be set to the timebase that the caller desires to use for this stream (note
199 * that the timebase actually used by the muxer can be different, as will be
201 * - It is advised to manually initialize only the relevant fields in
202 * AVCodecParameters, rather than using @ref avcodec_parameters_copy() during
203 * remuxing: there is no guarantee that the codec context values remain valid
204 * for both input and output format contexts.
205 * - The caller may fill in additional information, such as @ref
206 * AVFormatContext.metadata "global" or @ref AVStream.metadata "per-stream"
207 * metadata, @ref AVFormatContext.chapters "chapters", @ref
208 * AVFormatContext.programs "programs", etc. as described in the
209 * AVFormatContext documentation. Whether such information will actually be
210 * stored in the output depends on what the container format and the muxer
213 * When the muxing context is fully set up, the caller must call
214 * avformat_write_header() to initialize the muxer internals and write the file
215 * header. Whether anything actually is written to the IO context at this step
216 * depends on the muxer, but this function must always be called. Any muxer
217 * private options must be passed in the options parameter to this function.
219 * The data is then sent to the muxer by repeatedly calling av_write_frame() or
220 * av_interleaved_write_frame() (consult those functions' documentation for
221 * discussion on the difference between them; only one of them may be used with
222 * a single muxing context, they should not be mixed). Do note that the timing
223 * information on the packets sent to the muxer must be in the corresponding
224 * AVStream's timebase. That timebase is set by the muxer (in the
225 * avformat_write_header() step) and may be different from the timebase
226 * requested by the caller.
228 * Once all the data has been written, the caller must call av_write_trailer()
229 * to flush any buffered packets and finalize the output file, then close the IO
230 * context (if any) and finally free the muxing context with
231 * avformat_free_context().
234 * @defgroup lavf_io I/O Read/Write
238 * @defgroup lavf_codec Demuxers
240 * @defgroup lavf_codec_native Native Demuxers
243 * @defgroup lavf_codec_wrappers External library wrappers
247 * @defgroup lavf_protos I/O Protocols
250 * @defgroup lavf_internal Internal
257 #include <stdio.h> /* FILE */
258 #include "libavcodec/avcodec.h"
259 #include "libavutil/dict.h"
260 #include "libavutil/log.h"
263 #include "libavformat/version.h"
265 struct AVFormatContext;
269 * @defgroup metadata_api Public Metadata API
272 * The metadata API allows libavformat to export metadata tags to a client
273 * application when demuxing. Conversely it allows a client application to
274 * set metadata when muxing.
276 * Metadata is exported or set as pairs of key/value strings in the 'metadata'
277 * fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
278 * using the @ref lavu_dict "AVDictionary" API. Like all strings in Libav,
279 * metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
280 * exported by demuxers isn't checked to be valid UTF-8 in most cases.
282 * Important concepts to keep in mind:
283 * - Keys are unique; there can never be 2 tags with the same key. This is
284 * also meant semantically, i.e., a demuxer should not knowingly produce
285 * several keys that are literally different but semantically identical.
286 * E.g., key=Author5, key=Author6. In this example, all authors must be
287 * placed in the same tag.
288 * - Metadata is flat, not hierarchical; there are no subtags. If you
289 * want to store, e.g., the email address of the child of producer Alice
290 * and actor Bob, that could have key=alice_and_bobs_childs_email_address.
291 * - Several modifiers can be applied to the tag name. This is done by
292 * appending a dash character ('-') and the modifier name in the order
293 * they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
294 * - language -- a tag whose value is localized for a particular language
295 * is appended with the ISO 639-2/B 3-letter language code.
296 * For example: Author-ger=Michael, Author-eng=Mike
297 * The original/default language is in the unqualified "Author" tag.
298 * A demuxer should set a default if it sets any translated tag.
299 * - sorting -- a modified version of a tag that should be used for
300 * sorting will have '-sort' appended. E.g. artist="The Beatles",
301 * artist-sort="Beatles, The".
302 * - Some protocols and demuxers support metadata updates. After a successful
303 * call to av_read_packet(), AVFormatContext.event_flags or AVStream.event_flags
304 * will be updated to indicate if metadata changed. In order to detect metadata
305 * changes on a stream, you need to loop through all streams in the AVFormatContext
306 * and check their individual event_flags.
308 * - Demuxers attempt to export metadata in a generic format, however tags
309 * with no generic equivalents are left as they are stored in the container.
310 * Follows a list of generic tag names:
313 album -- name of the set this work belongs to
314 album_artist -- main creator of the set/album, if different from artist.
315 e.g. "Various Artists" for compilation albums.
316 artist -- main creator of the work
317 comment -- any additional description of the file.
318 composer -- who composed the work, if different from artist.
319 copyright -- name of copyright holder.
320 creation_time-- date when the file was created, preferably in ISO 8601.
321 date -- date when the work was created, preferably in ISO 8601.
322 disc -- number of a subset, e.g. disc in a multi-disc collection.
323 encoder -- name/settings of the software/hardware that produced the file.
324 encoded_by -- person/group who created the file.
325 filename -- original name of the file.
326 genre -- <self-evident>.
327 language -- main language in which the work is performed, preferably
328 in ISO 639-2 format. Multiple languages can be specified by
329 separating them with commas.
330 performer -- artist who performed the work, if different from artist.
331 E.g for "Also sprach Zarathustra", artist would be "Richard
332 Strauss" and performer "London Philharmonic Orchestra".
333 publisher -- name of the label/publisher.
334 service_name -- name of the service in broadcasting (channel name).
335 service_provider -- name of the service provider in broadcasting.
336 title -- name of the work.
337 track -- number of this work in the set, can be in form current/total.
338 variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
341 * Look in the examples section for an application example how to use the Metadata API.
346 /* packet functions */
350 * Allocate and read the payload of a packet and initialize its
351 * fields with default values.
353 * @param s associated IO context
355 * @param size desired payload size
356 * @return >0 (read size) if OK, AVERROR_xxx otherwise
358 int av_get_packet(AVIOContext *s, AVPacket *pkt, int size);
362 * Read data and append it to the current content of the AVPacket.
363 * If pkt->size is 0 this is identical to av_get_packet.
364 * Note that this uses av_grow_packet and thus involves a realloc
365 * which is inefficient. Thus this function should only be used
366 * when there is no reasonable way to know (an upper bound of)
369 * @param s associated IO context
371 * @param size amount of data to read
372 * @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
373 * will not be lost even if an error occurs.
375 int av_append_packet(AVIOContext *s, AVPacket *pkt, int size);
377 /*************************************************/
378 /* input/output formats */
383 * This structure contains the data a format has to probe a file.
385 typedef struct AVProbeData {
386 const char *filename;
387 unsigned char *buf; /**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */
388 int buf_size; /**< Size of buf except extra allocated bytes */
389 const char *mime_type; /**< mime_type, when known. */
392 #define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
393 #define AVPROBE_SCORE_MIME 75 ///< score for file mime type
394 #define AVPROBE_SCORE_MAX 100 ///< maximum score
396 #define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
398 /// Demuxer will use avio_open, no opened file should be provided by the caller.
399 #define AVFMT_NOFILE 0x0001
400 #define AVFMT_NEEDNUMBER 0x0002 /**< Needs '%d' in filename. */
401 #define AVFMT_SHOW_IDS 0x0008 /**< Show format stream IDs numbers. */
402 #if FF_API_LAVF_FMT_RAWPICTURE
403 #define AVFMT_RAWPICTURE 0x0020 /**< Format wants AVPicture structure for
404 raw picture data. @deprecated Not used anymore */
406 #define AVFMT_GLOBALHEADER 0x0040 /**< Format wants global header. */
407 #define AVFMT_NOTIMESTAMPS 0x0080 /**< Format does not need / have any timestamps. */
408 #define AVFMT_GENERIC_INDEX 0x0100 /**< Use generic index building code. */
409 #define AVFMT_TS_DISCONT 0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
410 #define AVFMT_VARIABLE_FPS 0x0400 /**< Format allows variable fps. */
411 #define AVFMT_NODIMENSIONS 0x0800 /**< Format does not need width/height */
412 #define AVFMT_NOSTREAMS 0x1000 /**< Format does not require any streams */
413 #define AVFMT_NOBINSEARCH 0x2000 /**< Format does not allow to fall back on binary search via read_timestamp */
414 #define AVFMT_NOGENSEARCH 0x4000 /**< Format does not allow to fall back on generic search */
415 #define AVFMT_NO_BYTE_SEEK 0x8000 /**< Format does not allow seeking by bytes */
416 #define AVFMT_ALLOW_FLUSH 0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
417 #define AVFMT_TS_NONSTRICT 0x20000 /**< Format does not require strictly
418 increasing timestamps, but they must
419 still be monotonic */
420 #define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative
421 timestamps. If not set the timestamp
422 will be shifted in av_write_frame and
423 av_interleaved_write_frame so they
427 * @addtogroup lavf_encoding
430 typedef struct AVOutputFormat {
433 * Descriptive name for the format, meant to be more human-readable
434 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
437 const char *long_name;
438 const char *mime_type;
439 const char *extensions; /**< comma-separated filename extensions */
441 enum AVCodecID audio_codec; /**< default audio codec */
442 enum AVCodecID video_codec; /**< default video codec */
443 enum AVCodecID subtitle_codec; /**< default subtitle codec */
445 * can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER,
446 * AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
447 * AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
448 * AVFMT_TS_NONSTRICT, AVFMT_TS_NEGATIVE
453 * List of supported codec_id-codec_tag pairs, ordered by "better
454 * choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
456 const struct AVCodecTag * const *codec_tag;
459 const AVClass *priv_class; ///< AVClass for the private context
461 /*****************************************************************
462 * No fields below this line are part of the public API. They
463 * may not be used outside of libavformat and can be changed and
465 * New public fields should be added right above.
466 *****************************************************************
468 struct AVOutputFormat *next;
470 * size of private data so that it can be allocated in the wrapper
474 int (*write_header)(struct AVFormatContext *);
476 * Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,
477 * pkt can be NULL in order to flush data buffered in the muxer.
478 * When flushing, return 0 if there still is more data to flush,
479 * or 1 if everything was flushed and there is no more buffered
482 int (*write_packet)(struct AVFormatContext *, AVPacket *pkt);
483 int (*write_trailer)(struct AVFormatContext *);
485 * Currently only used to set pixel format if not YUV420P.
487 int (*interleave_packet)(struct AVFormatContext *, AVPacket *out,
488 AVPacket *in, int flush);
490 * Test if the given codec can be stored in this container.
492 * @return 1 if the codec is supported, 0 if it is not.
493 * A negative number if unknown.
495 int (*query_codec)(enum AVCodecID id, int std_compliance);
502 * @addtogroup lavf_decoding
505 typedef struct AVInputFormat {
507 * A comma separated list of short names for the format. New names
508 * may be appended with a minor bump.
513 * Descriptive name for the format, meant to be more human-readable
514 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
517 const char *long_name;
520 * Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
521 * AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
522 * AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK.
527 * If extensions are defined, then no probe is done. You should
528 * usually not use extension format guessing because it is not
531 const char *extensions;
533 const struct AVCodecTag * const *codec_tag;
535 const AVClass *priv_class; ///< AVClass for the private context
538 * Comma-separated list of mime types.
539 * It is used check for matching mime types while probing.
540 * @see av_probe_input_format2
542 const char *mime_type;
544 /*****************************************************************
545 * No fields below this line are part of the public API. They
546 * may not be used outside of libavformat and can be changed and
548 * New public fields should be added right above.
549 *****************************************************************
551 struct AVInputFormat *next;
554 * Raw demuxers store their codec ID here.
559 * Size of private data so that it can be allocated in the wrapper.
564 * Tell if a given file has a chance of being parsed as this format.
565 * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
566 * big so you do not have to check for that unless you need more.
568 int (*read_probe)(AVProbeData *);
571 * Read the format header and initialize the AVFormatContext
572 * structure. Return 0 if OK. 'avformat_new_stream' should be
573 * called to create new streams.
575 int (*read_header)(struct AVFormatContext *);
578 * Read one packet and put it in 'pkt'. pts and flags are also
579 * set. 'avformat_new_stream' can be called only if the flag
580 * AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
581 * background thread).
582 * @return 0 on success, < 0 on error.
583 * When returning an error, pkt must not have been allocated
584 * or must be freed before returning
586 int (*read_packet)(struct AVFormatContext *, AVPacket *pkt);
589 * Close the stream. The AVFormatContext and AVStreams are not
590 * freed by this function
592 int (*read_close)(struct AVFormatContext *);
595 * Seek to a given timestamp relative to the frames in
596 * stream component stream_index.
597 * @param stream_index Must not be -1.
598 * @param flags Selects which direction should be preferred if no exact
599 * match is available.
600 * @return >= 0 on success (but not necessarily the new offset)
602 int (*read_seek)(struct AVFormatContext *,
603 int stream_index, int64_t timestamp, int flags);
606 * Get the next timestamp in stream[stream_index].time_base units.
607 * @return the timestamp or AV_NOPTS_VALUE if an error occurred
609 int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index,
610 int64_t *pos, int64_t pos_limit);
613 * Start/resume playing - only meaningful if using a network-based format
616 int (*read_play)(struct AVFormatContext *);
619 * Pause playing - only meaningful if using a network-based format
622 int (*read_pause)(struct AVFormatContext *);
625 * Seek to timestamp ts.
626 * Seeking will be done so that the point from which all active streams
627 * can be presented successfully will be closest to ts and within min/max_ts.
628 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
630 int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
636 enum AVStreamParseType {
638 AVSTREAM_PARSE_FULL, /**< full parsing and repack */
639 AVSTREAM_PARSE_HEADERS, /**< Only parse headers, do not repack. */
640 AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */
641 AVSTREAM_PARSE_FULL_ONCE, /**< full parsing and repack of the first frame only, only implemented for H.264 currently */
644 typedef struct AVIndexEntry {
647 #define AVINDEX_KEYFRAME 0x0001
649 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).
650 int min_distance; /**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */
653 #define AV_DISPOSITION_DEFAULT 0x0001
654 #define AV_DISPOSITION_DUB 0x0002
655 #define AV_DISPOSITION_ORIGINAL 0x0004
656 #define AV_DISPOSITION_COMMENT 0x0008
657 #define AV_DISPOSITION_LYRICS 0x0010
658 #define AV_DISPOSITION_KARAOKE 0x0020
661 * Track should be used during playback by default.
662 * Useful for subtitle track that should be displayed
663 * even when user did not explicitly ask for subtitles.
665 #define AV_DISPOSITION_FORCED 0x0040
666 #define AV_DISPOSITION_HEARING_IMPAIRED 0x0080 /**< stream for hearing impaired audiences */
667 #define AV_DISPOSITION_VISUAL_IMPAIRED 0x0100 /**< stream for visual impaired audiences */
668 #define AV_DISPOSITION_CLEAN_EFFECTS 0x0200 /**< stream without voice */
670 * The stream is stored in the file as an attached picture/"cover art" (e.g.
671 * APIC frame in ID3v2). The single packet associated with it will be returned
672 * among the first few packets read from the file unless seeking takes place.
673 * It can also be accessed at any time in AVStream.attached_pic.
675 #define AV_DISPOSITION_ATTACHED_PIC 0x0400
677 typedef struct AVStreamInternal AVStreamInternal;
681 * New fields can be added to the end with minor version bumps.
682 * Removal, reordering and changes to existing fields require a major
684 * sizeof(AVStream) must not be used outside libav*.
686 typedef struct AVStream {
687 int index; /**< stream index in AVFormatContext */
689 * Format-specific stream ID.
690 * decoding: set by libavformat
691 * encoding: set by the user, replaced by libavformat if left unset
694 #if FF_API_LAVF_AVCTX
696 * @deprecated use the codecpar struct instead
699 AVCodecContext *codec;
704 * This is the fundamental unit of time (in seconds) in terms
705 * of which frame timestamps are represented.
707 * decoding: set by libavformat
708 * encoding: May be set by the caller before avformat_write_header() to
709 * provide a hint to the muxer about the desired timebase. In
710 * avformat_write_header(), the muxer will overwrite this field
711 * with the timebase that will actually be used for the timestamps
712 * written into the file (which may or may not be related to the
713 * user-provided one, depending on the format).
715 AVRational time_base;
718 * Decoding: pts of the first frame of the stream, in stream time base.
719 * Only set this if you are absolutely 100% sure that the value you set
720 * it to really is the pts of the first frame.
721 * This may be undefined (AV_NOPTS_VALUE).
726 * Decoding: duration of the stream, in stream time base.
727 * If a source file does not specify a duration, but does specify
728 * a bitrate, this value will be estimated from bitrate and file size.
732 int64_t nb_frames; ///< number of frames in this stream if known or 0
734 int disposition; /**< AV_DISPOSITION_* bit field */
736 enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
739 * sample aspect ratio (0 if unknown)
740 * - encoding: Set by user.
741 * - decoding: Set by libavformat.
743 AVRational sample_aspect_ratio;
745 AVDictionary *metadata;
750 * - demuxing: May be set by libavformat when creating the stream or in
751 * avformat_find_stream_info().
752 * - muxing: May be set by the caller before avformat_write_header().
754 AVRational avg_frame_rate;
757 * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
758 * will contain the attached picture.
760 * decoding: set by libavformat, must not be modified by the caller.
763 AVPacket attached_pic;
766 * An array of side data that applies to the whole stream (i.e. the
767 * container does not allow it to change between packets).
769 * There may be no overlap between the side data in this array and side data
770 * in the packets. I.e. a given side data is either exported by the muxer
771 * (demuxing) / set by the caller (muxing) in this array, then it never
772 * appears in the packets, or the side data is exported / sent through
773 * the packets (always in the first packet where the value becomes known or
774 * changes), then it does not appear in this array.
776 * - demuxing: Set by libavformat when the stream is created.
777 * - muxing: May be set by the caller before avformat_write_header().
779 * Freed by libavformat in avformat_free_context().
781 AVPacketSideData *side_data;
783 * The number of elements in the AVStream.side_data array.
788 * Flags for the user to detect events happening on the stream. Flags must
789 * be cleared by the user once the event has been handled.
790 * A combination of AVSTREAM_EVENT_FLAG_*.
793 #define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
796 * Codec parameters associated with this stream. Allocated and freed by
797 * libavformat in avformat_new_stream() and avformat_free_context()
800 * - demuxing: filled by libavformat on stream creation or in
801 * avformat_find_stream_info()
802 * - muxing: filled by the caller before avformat_write_header()
804 AVCodecParameters *codecpar;
806 /*****************************************************************
807 * All fields below this line are not part of the public API. They
808 * may not be used outside of libavformat and can be changed and
810 * New public fields should be added right above.
811 *****************************************************************
815 * Stream information used internally by av_find_stream_info()
817 #define MAX_STD_TIMEBASES (60*12+5)
819 int nb_decoded_frames;
823 * Those are used for average framerate estimation.
825 int64_t fps_first_dts;
826 int fps_first_dts_idx;
827 int64_t fps_last_dts;
828 int fps_last_dts_idx;
832 int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
834 // Timestamp generation support:
838 int last_IP_duration;
841 * Number of packets to buffer for codec probing
843 #define MAX_PROBE_PACKETS 2500
847 * Number of frames that have been demuxed during av_find_stream_info()
849 int codec_info_nb_frames;
851 /* av_read_frame() support */
852 enum AVStreamParseType need_parsing;
853 struct AVCodecParserContext *parser;
856 * last packet in packet_buffer for this stream when muxing.
858 struct AVPacketList *last_in_packet_buffer;
859 AVProbeData probe_data;
860 #define MAX_REORDER_DELAY 16
861 int64_t pts_buffer[MAX_REORDER_DELAY+1];
863 AVIndexEntry *index_entries; /**< Only used if the format does not
864 support seeking natively. */
865 int nb_index_entries;
866 unsigned int index_entries_allocated_size;
869 * An opaque field for libavformat internal usage.
870 * Must not be accessed in any way by callers.
872 AVStreamInternal *internal;
875 #define AV_PROGRAM_RUNNING 1
878 * New fields can be added to the end with minor version bumps.
879 * Removal, reordering and changes to existing fields require a major
881 * sizeof(AVProgram) must not be used outside libav*.
883 typedef struct AVProgram {
886 enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
887 unsigned int *stream_index;
888 unsigned int nb_stream_indexes;
889 AVDictionary *metadata;
892 #define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
893 (streams are added dynamically) */
895 typedef struct AVChapter {
896 int id; ///< unique ID to identify the chapter
897 AVRational time_base; ///< time base in which the start/end timestamps are specified
898 int64_t start, end; ///< chapter start/end time in time_base units
899 AVDictionary *metadata;
902 typedef struct AVFormatInternal AVFormatInternal;
905 * Format I/O context.
906 * New fields can be added to the end with minor version bumps.
907 * Removal, reordering and changes to existing fields require a major
909 * sizeof(AVFormatContext) must not be used outside libav*, use
910 * avformat_alloc_context() to create an AVFormatContext.
912 typedef struct AVFormatContext {
914 * A class for logging and @ref avoptions. Set by avformat_alloc_context().
915 * Exports (de)muxer private options if they exist.
917 const AVClass *av_class;
920 * The input container format.
922 * Demuxing only, set by avformat_open_input().
924 struct AVInputFormat *iformat;
927 * The output container format.
929 * Muxing only, must be set by the caller before avformat_write_header().
931 struct AVOutputFormat *oformat;
934 * Format private data. This is an AVOptions-enabled struct
935 * if and only if iformat/oformat.priv_class is not NULL.
937 * - muxing: set by avformat_write_header()
938 * - demuxing: set by avformat_open_input()
945 * - demuxing: either set by the user before avformat_open_input() (then
946 * the user must close it manually) or set by avformat_open_input().
947 * - muxing: set by the user before avformat_write_header(). The caller must
948 * take care of closing / freeing the IO context.
950 * Do NOT set this field if AVFMT_NOFILE flag is set in
951 * iformat/oformat.flags. In such a case, the (de)muxer will handle
952 * I/O in some other way and this field will be NULL.
958 * Flags signalling stream properties. A combination of AVFMTCTX_*.
959 * Set by libavformat.
964 * Number of elements in AVFormatContext.streams.
966 * Set by avformat_new_stream(), must not be modified by any other code.
968 unsigned int nb_streams;
970 * A list of all streams in the file. New streams are created with
971 * avformat_new_stream().
973 * - demuxing: streams are created by libavformat in avformat_open_input().
974 * If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
975 * appear in av_read_frame().
976 * - muxing: streams are created by the user before avformat_write_header().
978 * Freed by libavformat in avformat_free_context().
983 * input or output filename
985 * - demuxing: set by avformat_open_input()
986 * - muxing: may be set by the caller before avformat_write_header()
991 * Position of the first frame of the component, in
992 * AV_TIME_BASE fractional seconds. NEVER set this value directly:
993 * It is deduced from the AVStream values.
995 * Demuxing only, set by libavformat.
1000 * Duration of the stream, in AV_TIME_BASE fractional
1001 * seconds. Only set this value if you know none of the individual stream
1002 * durations and also do not set any of them. This is deduced from the
1003 * AVStream values if not set.
1005 * Demuxing only, set by libavformat.
1010 * Total stream bitrate in bit/s, 0 if not
1011 * available. Never set it directly if the file_size and the
1012 * duration are known as Libav can compute it automatically.
1016 unsigned int packet_size;
1020 * Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
1021 * Set by the user before avformat_open_input() / avformat_write_header().
1024 #define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
1025 #define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
1026 #define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
1027 #define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
1028 #define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container
1029 #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
1030 #define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
1031 #define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
1032 #define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
1033 #define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
1035 * When muxing, try to avoid writing any random/volatile data to the output.
1036 * This includes any random IDs, real-time timestamps/dates, muxer version, etc.
1038 * This flag is mainly intended for testing.
1040 #define AVFMT_FLAG_BITEXACT 0x0400
1043 * Maximum size of the data read from input for determining
1044 * the input container format.
1045 * Demuxing only, set by the caller before avformat_open_input().
1047 unsigned int probesize;
1050 * Maximum duration (in AV_TIME_BASE units) of the data read
1051 * from input in avformat_find_stream_info().
1052 * Demuxing only, set by the caller before avformat_find_stream_info().
1054 int max_analyze_duration;
1059 unsigned int nb_programs;
1060 AVProgram **programs;
1063 * Forced video codec_id.
1064 * Demuxing: Set by user.
1066 enum AVCodecID video_codec_id;
1069 * Forced audio codec_id.
1070 * Demuxing: Set by user.
1072 enum AVCodecID audio_codec_id;
1075 * Forced subtitle codec_id.
1076 * Demuxing: Set by user.
1078 enum AVCodecID subtitle_codec_id;
1081 * Maximum amount of memory in bytes to use for the index of each stream.
1082 * If the index exceeds this size, entries will be discarded as
1083 * needed to maintain a smaller size. This can lead to slower or less
1084 * accurate seeking (depends on demuxer).
1085 * Demuxers for which a full in-memory index is mandatory will ignore
1088 * - demuxing: set by user
1090 unsigned int max_index_size;
1093 * Maximum amount of memory in bytes to use for buffering frames
1094 * obtained from realtime capture devices.
1096 unsigned int max_picture_buffer;
1099 * Number of chapters in AVChapter array.
1100 * When muxing, chapters are normally written in the file header,
1101 * so nb_chapters should normally be initialized before write_header
1102 * is called. Some muxers (e.g. mov and mkv) can also write chapters
1103 * in the trailer. To write chapters in the trailer, nb_chapters
1104 * must be zero when write_header is called and non-zero when
1105 * write_trailer is called.
1106 * - muxing: set by user
1107 * - demuxing: set by libavformat
1109 unsigned int nb_chapters;
1110 AVChapter **chapters;
1113 * Metadata that applies to the whole file.
1115 * - demuxing: set by libavformat in avformat_open_input()
1116 * - muxing: may be set by the caller before avformat_write_header()
1118 * Freed by libavformat in avformat_free_context().
1120 AVDictionary *metadata;
1123 * Start time of the stream in real world time, in microseconds
1124 * since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1125 * stream was captured at this real world time.
1126 * Muxing only, set by the caller before avformat_write_header().
1128 int64_t start_time_realtime;
1131 * The number of frames used for determining the framerate in
1132 * avformat_find_stream_info().
1133 * Demuxing only, set by the caller before avformat_find_stream_info().
1138 * Error recognition; higher values will detect more errors but may
1139 * misdetect some more or less valid parts as errors.
1140 * Demuxing only, set by the caller before avformat_open_input().
1142 int error_recognition;
1145 * Custom interrupt callbacks for the I/O layer.
1147 * demuxing: set by the user before avformat_open_input().
1148 * muxing: set by the user before avformat_write_header()
1149 * (mainly useful for AVFMT_NOFILE formats). The callback
1150 * should also be passed to avio_open2() if it's used to
1153 AVIOInterruptCB interrupt_callback;
1156 * Flags to enable debugging.
1159 #define FF_FDEBUG_TS 0x0001
1162 * Maximum buffering duration for interleaving.
1164 * To ensure all the streams are interleaved correctly,
1165 * av_interleaved_write_frame() will wait until it has at least one packet
1166 * for each stream before actually writing any packets to the output file.
1167 * When some streams are "sparse" (i.e. there are large gaps between
1168 * successive packets), this can result in excessive buffering.
1170 * This field specifies the maximum difference between the timestamps of the
1171 * first and the last packet in the muxing queue, above which libavformat
1172 * will output a packet regardless of whether it has queued a packet for all
1175 * Muxing only, set by the caller before avformat_write_header().
1177 int64_t max_interleave_delta;
1180 * Allow non-standard and experimental extension
1181 * @see AVCodecContext.strict_std_compliance
1183 int strict_std_compliance;
1186 * Flags for the user to detect events happening on the file. Flags must
1187 * be cleared by the user once the event has been handled.
1188 * A combination of AVFMT_EVENT_FLAG_*.
1191 #define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
1194 * Maximum number of packets to read while waiting for the first timestamp.
1200 * Avoid negative timestamps during muxing.
1201 * Any value of the AVFMT_AVOID_NEG_TS_* constants.
1202 * Note, this only works when using av_interleaved_write_frame.
1203 * - muxing: Set by user
1204 * - demuxing: unused
1206 int avoid_negative_ts;
1207 #define AVFMT_AVOID_NEG_TS_AUTO -1 ///< Enabled when required by target format
1208 #define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
1209 #define AVFMT_AVOID_NEG_TS_MAKE_ZERO 2 ///< Shift timestamps so that they start at 0
1212 * An opaque field for libavformat internal usage.
1213 * Must not be accessed in any way by callers.
1215 AVFormatInternal *internal;
1218 * Arbitrary user data set by the caller.
1223 * A callback for opening new IO streams.
1225 * Whenever a muxer or a demuxer needs to open an IO stream (typically from
1226 * avformat_open_input() for demuxers, but for certain formats can happen at
1227 * other times as well), it will call this callback to obtain an IO context.
1229 * @param s the format context
1230 * @param pb on success, the newly opened IO context should be returned here
1231 * @param url the url to open
1232 * @param flags a combination of AVIO_FLAG_*
1233 * @param options a dictionary of additional options, with the same
1234 * semantics as in avio_open2()
1235 * @return 0 on success, a negative AVERROR code on failure
1237 * @note Certain muxers and demuxers do nesting, i.e. they open one or more
1238 * additional internal format contexts. Thus the AVFormatContext pointer
1239 * passed to this callback may be different from the one facing the caller.
1240 * It will, however, have the same 'opaque' field.
1242 int (*io_open)(struct AVFormatContext *s, AVIOContext **pb, const char *url,
1243 int flags, AVDictionary **options);
1246 * A callback for closing the streams opened with AVFormatContext.io_open().
1248 void (*io_close)(struct AVFormatContext *s, AVIOContext *pb);
1251 * A comma-separated list of protocol names that will not be used internally
1252 * by libavformat. If this field is a non-empty string, then protocols
1253 * listed here will be forbidden.
1255 * This field should be set using AVOptions.
1257 char *protocol_blacklist;
1260 * A comma-separated list of protocol names that can be used internally by
1261 * libavformat. If this field is a non-empty string, all protocols not
1262 * listed here will be forbidden.
1264 * This field should be set using AVOptions.
1266 char *protocol_whitelist;
1269 typedef struct AVPacketList {
1271 struct AVPacketList *next;
1276 * @defgroup lavf_core Core functions
1279 * Functions for querying libavformat capabilities, allocating core structures,
1285 * Return the LIBAVFORMAT_VERSION_INT constant.
1287 unsigned avformat_version(void);
1290 * Return the libavformat build-time configuration.
1292 const char *avformat_configuration(void);
1295 * Return the libavformat license.
1297 const char *avformat_license(void);
1300 * Initialize libavformat and register all the muxers, demuxers and
1301 * protocols. If you do not call this function, then you can select
1302 * exactly which formats you want to support.
1304 * @see av_register_input_format()
1305 * @see av_register_output_format()
1306 * @see av_register_protocol()
1308 void av_register_all(void);
1310 void av_register_input_format(AVInputFormat *format);
1311 void av_register_output_format(AVOutputFormat *format);
1314 * Do global initialization of network components. This is optional,
1315 * but recommended, since it avoids the overhead of implicitly
1316 * doing the setup for each session.
1318 * Calling this function will become mandatory if using network
1319 * protocols at some major version bump.
1321 int avformat_network_init(void);
1324 * Undo the initialization done by avformat_network_init.
1326 int avformat_network_deinit(void);
1329 * If f is NULL, returns the first registered input format,
1330 * if f is non-NULL, returns the next registered input format after f
1331 * or NULL if f is the last one.
1333 AVInputFormat *av_iformat_next(const AVInputFormat *f);
1336 * If f is NULL, returns the first registered output format,
1337 * if f is non-NULL, returns the next registered output format after f
1338 * or NULL if f is the last one.
1340 AVOutputFormat *av_oformat_next(const AVOutputFormat *f);
1343 * Allocate an AVFormatContext.
1344 * avformat_free_context() can be used to free the context and everything
1345 * allocated by the framework within it.
1347 AVFormatContext *avformat_alloc_context(void);
1350 * Free an AVFormatContext and all its streams.
1351 * @param s context to free
1353 void avformat_free_context(AVFormatContext *s);
1356 * Get the AVClass for AVFormatContext. It can be used in combination with
1357 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
1359 * @see av_opt_find().
1361 const AVClass *avformat_get_class(void);
1364 * Add a new stream to a media file.
1366 * When demuxing, it is called by the demuxer in read_header(). If the
1367 * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
1368 * be called in read_packet().
1370 * When muxing, should be called by the user before avformat_write_header().
1372 * @param s media file handle
1373 * @param c If non-NULL, the AVCodecContext corresponding to the new stream
1374 * will be initialized to use this codec. This is needed for e.g. codec-specific
1375 * defaults to be set, so codec should be provided if it is known.
1377 * @return newly created stream or NULL on error.
1379 AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c);
1382 * Wrap an existing array as stream side data.
1385 * @param type side information type
1386 * @param data the side data array. It must be allocated with the av_malloc()
1387 * family of functions. The ownership of the data is transferred to
1389 * @param size side information size
1390 * @return zero on success, a negative AVERROR code on failure. On failure,
1391 * the stream is unchanged and the data remains owned by the caller.
1393 int av_stream_add_side_data(AVStream *st, enum AVPacketSideDataType type,
1394 uint8_t *data, size_t size);
1397 * Allocate new information from stream.
1399 * @param stream stream
1400 * @param type desired side information type
1401 * @param size side information size
1402 * @return pointer to fresh allocated data or NULL otherwise
1404 uint8_t *av_stream_new_side_data(AVStream *stream,
1405 enum AVPacketSideDataType type, int size);
1407 * Get side information from stream.
1409 * @param stream stream
1410 * @param type desired side information type
1411 * @param size pointer for side information size to store (optional)
1412 * @return pointer to data if present or NULL otherwise
1414 uint8_t *av_stream_get_side_data(AVStream *stream,
1415 enum AVPacketSideDataType type, int *size);
1417 AVProgram *av_new_program(AVFormatContext *s, int id);
1425 * @addtogroup lavf_decoding
1430 * Find AVInputFormat based on the short name of the input format.
1432 AVInputFormat *av_find_input_format(const char *short_name);
1435 * Guess the file format.
1437 * @param pd data to be probed
1438 * @param is_opened Whether the file is already opened; determines whether
1439 * demuxers with or without AVFMT_NOFILE are probed.
1441 AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened);
1444 * Guess the file format.
1446 * @param pd data to be probed
1447 * @param is_opened Whether the file is already opened; determines whether
1448 * demuxers with or without AVFMT_NOFILE are probed.
1449 * @param score_max A probe score larger that this is required to accept a
1450 * detection, the variable is set to the actual detection
1452 * If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
1453 * to retry with a larger probe buffer.
1455 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max);
1458 * Probe a bytestream to determine the input format. Each time a probe returns
1459 * with a score that is too low, the probe buffer size is increased and another
1460 * attempt is made. When the maximum probe size is reached, the input format
1461 * with the highest score is returned.
1463 * @param pb the bytestream to probe
1464 * @param fmt the input format is put here
1465 * @param filename the filename of the stream
1466 * @param logctx the log context
1467 * @param offset the offset within the bytestream to probe from
1468 * @param max_probe_size the maximum probe buffer size (zero for default)
1469 * @return 0 in case of success, a negative value corresponding to an
1470 * AVERROR code otherwise
1472 int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
1473 const char *filename, void *logctx,
1474 unsigned int offset, unsigned int max_probe_size);
1477 * Open an input stream and read the header. The codecs are not opened.
1478 * The stream must be closed with avformat_close_input().
1480 * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
1481 * May be a pointer to NULL, in which case an AVFormatContext is allocated by this
1482 * function and written into ps.
1483 * Note that a user-supplied AVFormatContext will be freed on failure.
1484 * @param filename Name of the stream to open.
1485 * @param fmt If non-NULL, this parameter forces a specific input format.
1486 * Otherwise the format is autodetected.
1487 * @param options A dictionary filled with AVFormatContext and demuxer-private options.
1488 * On return this parameter will be destroyed and replaced with a dict containing
1489 * options that were not found. May be NULL.
1491 * @return 0 on success, a negative AVERROR on failure.
1493 * @note If you want to use custom IO, preallocate the format context and set its pb field.
1495 int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options);
1498 * Read packets of a media file to get stream information. This
1499 * is useful for file formats with no headers such as MPEG. This
1500 * function also computes the real framerate in case of MPEG-2 repeat
1502 * The logical file position is not changed by this function;
1503 * examined packets may be buffered for later processing.
1505 * @param ic media file handle
1506 * @param options If non-NULL, an ic.nb_streams long array of pointers to
1507 * dictionaries, where i-th member contains options for
1508 * codec corresponding to i-th stream.
1509 * On return each dictionary will be filled with options that were not found.
1510 * @return >=0 if OK, AVERROR_xxx on error
1512 * @note this function isn't guaranteed to open all the codecs, so
1513 * options being non-empty at return is a perfectly normal behavior.
1515 * @todo Let the user decide somehow what information is needed so that
1516 * we do not waste time getting stuff the user does not need.
1518 int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options);
1521 * Find the "best" stream in the file.
1522 * The best stream is determined according to various heuristics as the most
1523 * likely to be what the user expects.
1524 * If the decoder parameter is non-NULL, av_find_best_stream will find the
1525 * default decoder for the stream's codec; streams for which no decoder can
1526 * be found are ignored.
1528 * @param ic media file handle
1529 * @param type stream type: video, audio, subtitles, etc.
1530 * @param wanted_stream_nb user-requested stream number,
1531 * or -1 for automatic selection
1532 * @param related_stream try to find a stream related (eg. in the same
1533 * program) to this one, or -1 if none
1534 * @param decoder_ret if non-NULL, returns the decoder for the
1536 * @param flags flags; none are currently defined
1537 * @return the non-negative stream number in case of success,
1538 * AVERROR_STREAM_NOT_FOUND if no stream with the requested type
1540 * AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
1541 * @note If av_find_best_stream returns successfully and decoder_ret is not
1542 * NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
1544 int av_find_best_stream(AVFormatContext *ic,
1545 enum AVMediaType type,
1546 int wanted_stream_nb,
1548 AVCodec **decoder_ret,
1552 * Return the next frame of a stream.
1553 * This function returns what is stored in the file, and does not validate
1554 * that what is there are valid frames for the decoder. It will split what is
1555 * stored in the file into frames and return one for each call. It will not
1556 * omit invalid data between valid frames so as to give the decoder the maximum
1557 * information possible for decoding.
1559 * If pkt->buf is NULL, then the packet is valid until the next
1560 * av_read_frame() or until avformat_close_input(). Otherwise the packet
1561 * is valid indefinitely. In both cases the packet must be freed with
1562 * av_packet_unref when it is no longer needed. For video, the packet contains
1563 * exactly one frame. For audio, it contains an integer number of frames if each
1564 * frame has a known fixed size (e.g. PCM or ADPCM data). If the audio frames
1565 * have a variable size (e.g. MPEG audio), then it contains one frame.
1567 * pkt->pts, pkt->dts and pkt->duration are always set to correct
1568 * values in AVStream.time_base units (and guessed if the format cannot
1569 * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
1570 * has B-frames, so it is better to rely on pkt->dts if you do not
1571 * decompress the payload.
1573 * @return 0 if OK, < 0 on error or end of file
1575 int av_read_frame(AVFormatContext *s, AVPacket *pkt);
1578 * Seek to the keyframe at timestamp.
1579 * 'timestamp' in 'stream_index'.
1581 * @param s media file handle
1582 * @param stream_index If stream_index is (-1), a default
1583 * stream is selected, and timestamp is automatically converted
1584 * from AV_TIME_BASE units to the stream specific time_base.
1585 * @param timestamp Timestamp in AVStream.time_base units
1586 * or, if no stream is specified, in AV_TIME_BASE units.
1587 * @param flags flags which select direction and seeking mode
1588 * @return >= 0 on success
1590 int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
1594 * Seek to timestamp ts.
1595 * Seeking will be done so that the point from which all active streams
1596 * can be presented successfully will be closest to ts and within min/max_ts.
1597 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
1599 * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
1600 * are the file position (this may not be supported by all demuxers).
1601 * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
1602 * in the stream with stream_index (this may not be supported by all demuxers).
1603 * Otherwise all timestamps are in units of the stream selected by stream_index
1604 * or if stream_index is -1, in AV_TIME_BASE units.
1605 * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
1606 * keyframes (this may not be supported by all demuxers).
1608 * @param s media file handle
1609 * @param stream_index index of the stream which is used as time base reference
1610 * @param min_ts smallest acceptable timestamp
1611 * @param ts target timestamp
1612 * @param max_ts largest acceptable timestamp
1613 * @param flags flags
1614 * @return >=0 on success, error code otherwise
1616 * @note This is part of the new seek API which is still under construction.
1617 * Thus do not use this yet. It may change at any time, do not expect
1618 * ABI compatibility yet!
1620 int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
1623 * Start playing a network-based stream (e.g. RTSP stream) at the
1626 int av_read_play(AVFormatContext *s);
1629 * Pause a network-based stream (e.g. RTSP stream).
1631 * Use av_read_play() to resume it.
1633 int av_read_pause(AVFormatContext *s);
1636 * Close an opened input AVFormatContext. Free it and all its contents
1637 * and set *s to NULL.
1639 void avformat_close_input(AVFormatContext **s);
1644 #define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
1645 #define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
1646 #define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
1647 #define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
1650 * @addtogroup lavf_encoding
1654 * Allocate the stream private data and write the stream header to
1655 * an output media file.
1657 * @param s Media file handle, must be allocated with avformat_alloc_context().
1658 * Its oformat field must be set to the desired output format;
1659 * Its pb field must be set to an already opened AVIOContext.
1660 * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
1661 * On return this parameter will be destroyed and replaced with a dict containing
1662 * options that were not found. May be NULL.
1664 * @return 0 on success, negative AVERROR on failure.
1666 * @see av_opt_find, av_dict_set, avio_open, av_oformat_next.
1668 int avformat_write_header(AVFormatContext *s, AVDictionary **options);
1671 * Write a packet to an output media file.
1673 * This function passes the packet directly to the muxer, without any buffering
1674 * or reordering. The caller is responsible for correctly interleaving the
1675 * packets if the format requires it. Callers that want libavformat to handle
1676 * the interleaving should call av_interleaved_write_frame() instead of this
1679 * @param s media file handle
1680 * @param pkt The packet containing the data to be written. Note that unlike
1681 * av_interleaved_write_frame(), this function does not take
1682 * ownership of the packet passed to it (though some muxers may make
1683 * an internal reference to the input packet).
1685 * This parameter can be NULL (at any time, not just at the end), in
1686 * order to immediately flush data buffered within the muxer, for
1687 * muxers that buffer up data internally before writing it to the
1690 * Packet's @ref AVPacket.stream_index "stream_index" field must be
1691 * set to the index of the corresponding stream in @ref
1692 * AVFormatContext.streams "s->streams".
1694 * The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
1695 * must be set to correct values in the stream's timebase (unless the
1696 * output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
1697 * they can be set to AV_NOPTS_VALUE).
1698 * The dts for subsequent packets passed to this function must be strictly
1699 * increasing when compared in their respective timebases (unless the
1700 * output format is flagged with the AVFMT_TS_NONSTRICT, then they
1701 * merely have to be nondecreasing). @ref AVPacket.duration
1702 * "duration") should also be set if known.
1703 * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
1705 * @see av_interleaved_write_frame()
1707 int av_write_frame(AVFormatContext *s, AVPacket *pkt);
1710 * Write a packet to an output media file ensuring correct interleaving.
1712 * This function will buffer the packets internally as needed to make sure the
1713 * packets in the output file are properly interleaved in the order of
1714 * increasing dts. Callers doing their own interleaving should call
1715 * av_write_frame() instead of this function.
1717 * Using this function instead of av_write_frame() can give muxers advance
1718 * knowledge of future packets, improving e.g. the behaviour of the mp4
1719 * muxer for VFR content in fragmenting mode.
1721 * @param s media file handle
1722 * @param pkt The packet containing the data to be written.
1724 * If the packet is reference-counted, this function will take
1725 * ownership of this reference and unreference it later when it sees
1727 * The caller must not access the data through this reference after
1728 * this function returns. If the packet is not reference-counted,
1729 * libavformat will make a copy.
1731 * This parameter can be NULL (at any time, not just at the end), to
1732 * flush the interleaving queues.
1734 * Packet's @ref AVPacket.stream_index "stream_index" field must be
1735 * set to the index of the corresponding stream in @ref
1736 * AVFormatContext.streams "s->streams".
1738 * The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
1739 * must be set to correct values in the stream's timebase (unless the
1740 * output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
1741 * they can be set to AV_NOPTS_VALUE).
1742 * The dts for subsequent packets in one stream must be strictly
1743 * increasing (unless the output format is flagged with the
1744 * AVFMT_TS_NONSTRICT, then they merely have to be nondecreasing).
1745 * @ref AVPacket.duration "duration") should also be set if known.
1747 * @return 0 on success, a negative AVERROR on error. Libavformat will always
1748 * take care of freeing the packet, even if this function fails.
1750 * @see av_write_frame(), AVFormatContext.max_interleave_delta
1752 int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
1755 * Write the stream trailer to an output media file and free the
1756 * file private data.
1758 * May only be called after a successful call to avformat_write_header.
1760 * @param s media file handle
1761 * @return 0 if OK, AVERROR_xxx on error
1763 int av_write_trailer(AVFormatContext *s);
1766 * Return the output format in the list of registered output formats
1767 * which best matches the provided parameters, or return NULL if
1768 * there is no match.
1770 * @param short_name if non-NULL checks if short_name matches with the
1771 * names of the registered formats
1772 * @param filename if non-NULL checks if filename terminates with the
1773 * extensions of the registered formats
1774 * @param mime_type if non-NULL checks if mime_type matches with the
1775 * MIME type of the registered formats
1777 AVOutputFormat *av_guess_format(const char *short_name,
1778 const char *filename,
1779 const char *mime_type);
1782 * Guess the codec ID based upon muxer and filename.
1784 enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
1785 const char *filename, const char *mime_type,
1786 enum AVMediaType type);
1794 * @defgroup lavf_misc Utility functions
1798 * Miscellaneous utility functions related to both muxing and demuxing
1803 * Send a nice hexadecimal dump of a buffer to the specified file stream.
1805 * @param f The file stream pointer where the dump should be sent to.
1807 * @param size buffer size
1809 * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
1811 void av_hex_dump(FILE *f, const uint8_t *buf, int size);
1814 * Send a nice hexadecimal dump of a buffer to the log.
1816 * @param avcl A pointer to an arbitrary struct of which the first field is a
1817 * pointer to an AVClass struct.
1818 * @param level The importance level of the message, lower values signifying
1819 * higher importance.
1821 * @param size buffer size
1823 * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
1825 void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
1828 * Send a nice dump of a packet to the specified file stream.
1830 * @param f The file stream pointer where the dump should be sent to.
1831 * @param pkt packet to dump
1832 * @param dump_payload True if the payload must be displayed, too.
1833 * @param st AVStream that the packet belongs to
1835 void av_pkt_dump2(FILE *f, AVPacket *pkt, int dump_payload, AVStream *st);
1839 * Send a nice dump of a packet to the log.
1841 * @param avcl A pointer to an arbitrary struct of which the first field is a
1842 * pointer to an AVClass struct.
1843 * @param level The importance level of the message, lower values signifying
1844 * higher importance.
1845 * @param pkt packet to dump
1846 * @param dump_payload True if the payload must be displayed, too.
1847 * @param st AVStream that the packet belongs to
1849 void av_pkt_dump_log2(void *avcl, int level, AVPacket *pkt, int dump_payload,
1853 * Get the AVCodecID for the given codec tag tag.
1854 * If no codec id is found returns AV_CODEC_ID_NONE.
1856 * @param tags list of supported codec_id-codec_tag pairs, as stored
1857 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
1858 * @param tag codec tag to match to a codec ID
1860 enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
1863 * Get the codec tag for the given codec id id.
1864 * If no codec tag is found returns 0.
1866 * @param tags list of supported codec_id-codec_tag pairs, as stored
1867 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
1868 * @param id codec ID to match to a codec tag
1870 unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id);
1872 int av_find_default_stream_index(AVFormatContext *s);
1875 * Get the index for a specific timestamp.
1877 * @param st stream that the timestamp belongs to
1878 * @param timestamp timestamp to retrieve the index for
1879 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
1880 * to the timestamp which is <= the requested one, if backward
1881 * is 0, then it will be >=
1882 * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
1883 * @return < 0 if no such timestamp could be found
1885 int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
1888 * Add an index entry into a sorted list. Update the entry if the list
1889 * already contains it.
1891 * @param timestamp timestamp in the time base of the given stream
1893 int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
1894 int size, int distance, int flags);
1898 * Split a URL string into components.
1900 * The pointers to buffers for storing individual components may be null,
1901 * in order to ignore that component. Buffers for components not found are
1902 * set to empty strings. If the port is not found, it is set to a negative
1905 * @param proto the buffer for the protocol
1906 * @param proto_size the size of the proto buffer
1907 * @param authorization the buffer for the authorization
1908 * @param authorization_size the size of the authorization buffer
1909 * @param hostname the buffer for the host name
1910 * @param hostname_size the size of the hostname buffer
1911 * @param port_ptr a pointer to store the port number in
1912 * @param path the buffer for the path
1913 * @param path_size the size of the path buffer
1914 * @param url the URL to split
1916 void av_url_split(char *proto, int proto_size,
1917 char *authorization, int authorization_size,
1918 char *hostname, int hostname_size,
1920 char *path, int path_size,
1925 * Print detailed information about the input or output format, such as
1926 * duration, bitrate, streams, container, programs, metadata, side data,
1927 * codec and time base.
1929 * @param ic the context to analyze
1930 * @param index the index to print, if you have multiple inputs or outputs
1931 * @param url the URL to print, such as source or destination file
1932 * @param is_output whether the context is input or output
1934 void av_dump_format(AVFormatContext *ic,
1940 * Return in 'buf' the path with '%d' replaced by a number.
1942 * Also handles the '%0nd' format where 'n' is the total number
1943 * of digits and '%%'.
1945 * @param buf destination buffer
1946 * @param buf_size destination buffer size
1947 * @param path numbered sequence string
1948 * @param number frame number
1949 * @return 0 if OK, -1 on format error
1951 int av_get_frame_filename(char *buf, int buf_size,
1952 const char *path, int number);
1955 * Check whether filename actually is a numbered sequence generator.
1957 * @param filename possible numbered sequence string
1958 * @return 1 if a valid numbered sequence string, 0 otherwise
1960 int av_filename_number_test(const char *filename);
1963 * Generate an SDP for an RTP session.
1965 * Note, this overwrites the id values of AVStreams in the muxer contexts
1966 * for getting unique dynamic payload types.
1968 * @param ac array of AVFormatContexts describing the RTP streams. If the
1969 * array is composed by only one context, such context can contain
1970 * multiple AVStreams (one AVStream per RTP stream). Otherwise,
1971 * all the contexts in the array (an AVCodecContext per RTP stream)
1972 * must contain only one AVStream.
1973 * @param n_files number of AVCodecContexts contained in ac
1974 * @param buf buffer where the SDP will be stored (must be allocated by
1976 * @param size the size of the buffer
1977 * @return 0 if OK, AVERROR_xxx on error
1979 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
1982 * Return a positive value if the given filename has one of the given
1983 * extensions, 0 otherwise.
1985 * @param filename file name to check against the given extensions
1986 * @param extensions a comma-separated list of filename extensions
1988 int av_match_ext(const char *filename, const char *extensions);
1991 * Test if the given container can store a codec.
1993 * @param ofmt container to check for compatibility
1994 * @param codec_id codec to potentially store in container
1995 * @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
1997 * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
1998 * A negative number if this information is not available.
2000 int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id,
2001 int std_compliance);
2004 * @defgroup riff_fourcc RIFF FourCCs
2006 * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
2007 * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
2010 * uint32_t tag = MKTAG('H', '2', '6', '4');
2011 * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
2012 * enum AVCodecID id = av_codec_get_id(table, tag);
2016 * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
2018 const struct AVCodecTag *avformat_get_riff_video_tags(void);
2020 * @return the table mapping RIFF FourCCs for audio to AVCodecID.
2022 const struct AVCodecTag *avformat_get_riff_audio_tags(void);
2031 #endif /* AVFORMAT_AVFORMAT_H */