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_decode_video2(), avcodec_decode_audio4() or
153 * avcodec_decode_subtitle2() if the 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_free_packet() 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.codec "stream codec context" information, such as the
195 * codec @ref AVCodecContext.codec_type "type", @ref AVCodecContext.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 * AVCodecContext, rather than using @ref avcodec_copy_context() 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
258 #include <stdio.h> /* FILE */
259 #include "libavcodec/avcodec.h"
260 #include "libavutil/dict.h"
261 #include "libavutil/log.h"
264 #include "libavformat/version.h"
266 struct AVFormatContext;
270 * @defgroup metadata_api Public Metadata API
273 * The metadata API allows libavformat to export metadata tags to a client
274 * application when demuxing. Conversely it allows a client application to
275 * set metadata when muxing.
277 * Metadata is exported or set as pairs of key/value strings in the 'metadata'
278 * fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
279 * using the @ref lavu_dict "AVDictionary" API. Like all strings in Libav,
280 * metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
281 * exported by demuxers isn't checked to be valid UTF-8 in most cases.
283 * Important concepts to keep in mind:
284 * - Keys are unique; there can never be 2 tags with the same key. This is
285 * also meant semantically, i.e., a demuxer should not knowingly produce
286 * several keys that are literally different but semantically identical.
287 * E.g., key=Author5, key=Author6. In this example, all authors must be
288 * placed in the same tag.
289 * - Metadata is flat, not hierarchical; there are no subtags. If you
290 * want to store, e.g., the email address of the child of producer Alice
291 * and actor Bob, that could have key=alice_and_bobs_childs_email_address.
292 * - Several modifiers can be applied to the tag name. This is done by
293 * appending a dash character ('-') and the modifier name in the order
294 * they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
295 * - language -- a tag whose value is localized for a particular language
296 * is appended with the ISO 639-2/B 3-letter language code.
297 * For example: Author-ger=Michael, Author-eng=Mike
298 * The original/default language is in the unqualified "Author" tag.
299 * A demuxer should set a default if it sets any translated tag.
300 * - sorting -- a modified version of a tag that should be used for
301 * sorting will have '-sort' appended. E.g. artist="The Beatles",
302 * artist-sort="Beatles, The".
303 * - Some protocols and demuxers support metadata updates. After a successful
304 * call to av_read_packet(), AVFormatContext.event_flags or AVStream.event_flags
305 * will be updated to indicate if metadata changed. In order to detect metadata
306 * changes on a stream, you need to loop through all streams in the AVFormatContext
307 * and check their individual event_flags.
309 * - Demuxers attempt to export metadata in a generic format, however tags
310 * with no generic equivalents are left as they are stored in the container.
311 * Follows a list of generic tag names:
314 album -- name of the set this work belongs to
315 album_artist -- main creator of the set/album, if different from artist.
316 e.g. "Various Artists" for compilation albums.
317 artist -- main creator of the work
318 comment -- any additional description of the file.
319 composer -- who composed the work, if different from artist.
320 copyright -- name of copyright holder.
321 creation_time-- date when the file was created, preferably in ISO 8601.
322 date -- date when the work was created, preferably in ISO 8601.
323 disc -- number of a subset, e.g. disc in a multi-disc collection.
324 encoder -- name/settings of the software/hardware that produced the file.
325 encoded_by -- person/group who created the file.
326 filename -- original name of the file.
327 genre -- <self-evident>.
328 language -- main language in which the work is performed, preferably
329 in ISO 639-2 format. Multiple languages can be specified by
330 separating them with commas.
331 performer -- artist who performed the work, if different from artist.
332 E.g for "Also sprach Zarathustra", artist would be "Richard
333 Strauss" and performer "London Philharmonic Orchestra".
334 publisher -- name of the label/publisher.
335 service_name -- name of the service in broadcasting (channel name).
336 service_provider -- name of the service provider in broadcasting.
337 title -- name of the work.
338 track -- number of this work in the set, can be in form current/total.
339 variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
342 * Look in the examples section for an application example how to use the Metadata API.
347 /* packet functions */
351 * Allocate and read the payload of a packet and initialize its
352 * fields with default values.
354 * @param s associated IO context
356 * @param size desired payload size
357 * @return >0 (read size) if OK, AVERROR_xxx otherwise
359 int av_get_packet(AVIOContext *s, AVPacket *pkt, int size);
363 * Read data and append it to the current content of the AVPacket.
364 * If pkt->size is 0 this is identical to av_get_packet.
365 * Note that this uses av_grow_packet and thus involves a realloc
366 * which is inefficient. Thus this function should only be used
367 * when there is no reasonable way to know (an upper bound of)
370 * @param s associated IO context
372 * @param size amount of data to read
373 * @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
374 * will not be lost even if an error occurs.
376 int av_append_packet(AVIOContext *s, AVPacket *pkt, int size);
379 /*************************************************/
380 /* fractional numbers for exact pts handling */
383 * The exact value of the fractional number is: 'val + num / den'.
384 * num is assumed to be 0 <= num < den.
386 typedef struct AVFrac {
387 int64_t val, num, den;
391 /*************************************************/
392 /* input/output formats */
397 * This structure contains the data a format has to probe a file.
399 typedef struct AVProbeData {
400 const char *filename;
401 unsigned char *buf; /**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */
402 int buf_size; /**< Size of buf except extra allocated bytes */
403 const char *mime_type; /**< mime_type, when known. */
406 #define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
407 #define AVPROBE_SCORE_MIME 75 ///< score for file mime type
408 #define AVPROBE_SCORE_MAX 100 ///< maximum score
410 #define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
412 /// Demuxer will use avio_open, no opened file should be provided by the caller.
413 #define AVFMT_NOFILE 0x0001
414 #define AVFMT_NEEDNUMBER 0x0002 /**< Needs '%d' in filename. */
415 #define AVFMT_SHOW_IDS 0x0008 /**< Show format stream IDs numbers. */
416 #define AVFMT_RAWPICTURE 0x0020 /**< Format wants AVPicture structure for
418 #define AVFMT_GLOBALHEADER 0x0040 /**< Format wants global header. */
419 #define AVFMT_NOTIMESTAMPS 0x0080 /**< Format does not need / have any timestamps. */
420 #define AVFMT_GENERIC_INDEX 0x0100 /**< Use generic index building code. */
421 #define AVFMT_TS_DISCONT 0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
422 #define AVFMT_VARIABLE_FPS 0x0400 /**< Format allows variable fps. */
423 #define AVFMT_NODIMENSIONS 0x0800 /**< Format does not need width/height */
424 #define AVFMT_NOSTREAMS 0x1000 /**< Format does not require any streams */
425 #define AVFMT_NOBINSEARCH 0x2000 /**< Format does not allow to fall back on binary search via read_timestamp */
426 #define AVFMT_NOGENSEARCH 0x4000 /**< Format does not allow to fall back on generic search */
427 #define AVFMT_NO_BYTE_SEEK 0x8000 /**< Format does not allow seeking by bytes */
428 #define AVFMT_ALLOW_FLUSH 0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
429 #define AVFMT_TS_NONSTRICT 0x20000 /**< Format does not require strictly
430 increasing timestamps, but they must
431 still be monotonic */
432 #define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative
433 timestamps. If not set the timestamp
434 will be shifted in av_write_frame and
435 av_interleaved_write_frame so they
439 * @addtogroup lavf_encoding
442 typedef struct AVOutputFormat {
445 * Descriptive name for the format, meant to be more human-readable
446 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
449 const char *long_name;
450 const char *mime_type;
451 const char *extensions; /**< comma-separated filename extensions */
453 enum AVCodecID audio_codec; /**< default audio codec */
454 enum AVCodecID video_codec; /**< default video codec */
455 enum AVCodecID subtitle_codec; /**< default subtitle codec */
457 * can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_RAWPICTURE,
458 * AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
459 * AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
465 * List of supported codec_id-codec_tag pairs, ordered by "better
466 * choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
468 const struct AVCodecTag * const *codec_tag;
471 const AVClass *priv_class; ///< AVClass for the private context
473 /*****************************************************************
474 * No fields below this line are part of the public API. They
475 * may not be used outside of libavformat and can be changed and
477 * New public fields should be added right above.
478 *****************************************************************
480 struct AVOutputFormat *next;
482 * size of private data so that it can be allocated in the wrapper
486 int (*write_header)(struct AVFormatContext *);
488 * Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,
489 * pkt can be NULL in order to flush data buffered in the muxer.
490 * When flushing, return 0 if there still is more data to flush,
491 * or 1 if everything was flushed and there is no more buffered
494 int (*write_packet)(struct AVFormatContext *, AVPacket *pkt);
495 int (*write_trailer)(struct AVFormatContext *);
497 * Currently only used to set pixel format if not YUV420P.
499 int (*interleave_packet)(struct AVFormatContext *, AVPacket *out,
500 AVPacket *in, int flush);
502 * Test if the given codec can be stored in this container.
504 * @return 1 if the codec is supported, 0 if it is not.
505 * A negative number if unknown.
507 int (*query_codec)(enum AVCodecID id, int std_compliance);
514 * @addtogroup lavf_decoding
517 typedef struct AVInputFormat {
519 * A comma separated list of short names for the format. New names
520 * may be appended with a minor bump.
525 * Descriptive name for the format, meant to be more human-readable
526 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
529 const char *long_name;
532 * Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
533 * AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
534 * AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK.
539 * If extensions are defined, then no probe is done. You should
540 * usually not use extension format guessing because it is not
543 const char *extensions;
545 const struct AVCodecTag * const *codec_tag;
547 const AVClass *priv_class; ///< AVClass for the private context
550 * Comma-separated list of mime types.
551 * It is used check for matching mime types while probing.
552 * @see av_probe_input_format2
554 const char *mime_type;
556 /*****************************************************************
557 * No fields below this line are part of the public API. They
558 * may not be used outside of libavformat and can be changed and
560 * New public fields should be added right above.
561 *****************************************************************
563 struct AVInputFormat *next;
566 * Raw demuxers store their codec ID here.
571 * Size of private data so that it can be allocated in the wrapper.
576 * Tell if a given file has a chance of being parsed as this format.
577 * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
578 * big so you do not have to check for that unless you need more.
580 int (*read_probe)(AVProbeData *);
583 * Read the format header and initialize the AVFormatContext
584 * structure. Return 0 if OK. 'avformat_new_stream' should be
585 * called to create new streams.
587 int (*read_header)(struct AVFormatContext *);
590 * Read one packet and put it in 'pkt'. pts and flags are also
591 * set. 'avformat_new_stream' can be called only if the flag
592 * AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
593 * background thread).
594 * @return 0 on success, < 0 on error.
595 * When returning an error, pkt must not have been allocated
596 * or must be freed before returning
598 int (*read_packet)(struct AVFormatContext *, AVPacket *pkt);
601 * Close the stream. The AVFormatContext and AVStreams are not
602 * freed by this function
604 int (*read_close)(struct AVFormatContext *);
607 * Seek to a given timestamp relative to the frames in
608 * stream component stream_index.
609 * @param stream_index Must not be -1.
610 * @param flags Selects which direction should be preferred if no exact
611 * match is available.
612 * @return >= 0 on success (but not necessarily the new offset)
614 int (*read_seek)(struct AVFormatContext *,
615 int stream_index, int64_t timestamp, int flags);
618 * Get the next timestamp in stream[stream_index].time_base units.
619 * @return the timestamp or AV_NOPTS_VALUE if an error occurred
621 int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index,
622 int64_t *pos, int64_t pos_limit);
625 * Start/resume playing - only meaningful if using a network-based format
628 int (*read_play)(struct AVFormatContext *);
631 * Pause playing - only meaningful if using a network-based format
634 int (*read_pause)(struct AVFormatContext *);
637 * Seek to timestamp ts.
638 * Seeking will be done so that the point from which all active streams
639 * can be presented successfully will be closest to ts and within min/max_ts.
640 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
642 int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
648 enum AVStreamParseType {
650 AVSTREAM_PARSE_FULL, /**< full parsing and repack */
651 AVSTREAM_PARSE_HEADERS, /**< Only parse headers, do not repack. */
652 AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */
653 AVSTREAM_PARSE_FULL_ONCE, /**< full parsing and repack of the first frame only, only implemented for H.264 currently */
656 typedef struct AVIndexEntry {
659 #define AVINDEX_KEYFRAME 0x0001
661 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).
662 int min_distance; /**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */
665 #define AV_DISPOSITION_DEFAULT 0x0001
666 #define AV_DISPOSITION_DUB 0x0002
667 #define AV_DISPOSITION_ORIGINAL 0x0004
668 #define AV_DISPOSITION_COMMENT 0x0008
669 #define AV_DISPOSITION_LYRICS 0x0010
670 #define AV_DISPOSITION_KARAOKE 0x0020
673 * Track should be used during playback by default.
674 * Useful for subtitle track that should be displayed
675 * even when user did not explicitly ask for subtitles.
677 #define AV_DISPOSITION_FORCED 0x0040
678 #define AV_DISPOSITION_HEARING_IMPAIRED 0x0080 /**< stream for hearing impaired audiences */
679 #define AV_DISPOSITION_VISUAL_IMPAIRED 0x0100 /**< stream for visual impaired audiences */
680 #define AV_DISPOSITION_CLEAN_EFFECTS 0x0200 /**< stream without voice */
682 * The stream is stored in the file as an attached picture/"cover art" (e.g.
683 * APIC frame in ID3v2). The single packet associated with it will be returned
684 * among the first few packets read from the file unless seeking takes place.
685 * It can also be accessed at any time in AVStream.attached_pic.
687 #define AV_DISPOSITION_ATTACHED_PIC 0x0400
691 * New fields can be added to the end with minor version bumps.
692 * Removal, reordering and changes to existing fields require a major
694 * sizeof(AVStream) must not be used outside libav*.
696 typedef struct AVStream {
697 int index; /**< stream index in AVFormatContext */
699 * Format-specific stream ID.
700 * decoding: set by libavformat
701 * encoding: set by the user, replaced by libavformat if left unset
705 * Codec context associated with this stream. Allocated and freed by
708 * - decoding: The demuxer exports codec information stored in the headers
710 * - encoding: The user sets codec information, the muxer writes it to the
711 * output. Mandatory fields as specified in AVCodecContext
712 * documentation must be set even if this AVCodecContext is
713 * not actually used for encoding.
715 AVCodecContext *codec;
720 * @deprecated this field is unused
727 * This is the fundamental unit of time (in seconds) in terms
728 * of which frame timestamps are represented.
730 * decoding: set by libavformat
731 * encoding: May be set by the caller before avformat_write_header() to
732 * provide a hint to the muxer about the desired timebase. In
733 * avformat_write_header(), the muxer will overwrite this field
734 * with the timebase that will actually be used for the timestamps
735 * written into the file (which may or may not be related to the
736 * user-provided one, depending on the format).
738 AVRational time_base;
741 * Decoding: pts of the first frame of the stream, in stream time base.
742 * Only set this if you are absolutely 100% sure that the value you set
743 * it to really is the pts of the first frame.
744 * This may be undefined (AV_NOPTS_VALUE).
749 * Decoding: duration of the stream, in stream time base.
750 * If a source file does not specify a duration, but does specify
751 * a bitrate, this value will be estimated from bitrate and file size.
755 int64_t nb_frames; ///< number of frames in this stream if known or 0
757 int disposition; /**< AV_DISPOSITION_* bit field */
759 enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
762 * sample aspect ratio (0 if unknown)
763 * - encoding: Set by user.
764 * - decoding: Set by libavformat.
766 AVRational sample_aspect_ratio;
768 AVDictionary *metadata;
773 * - demuxing: May be set by libavformat when creating the stream or in
774 * avformat_find_stream_info().
775 * - muxing: May be set by the caller before avformat_write_header().
777 AVRational avg_frame_rate;
780 * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
781 * will contain the attached picture.
783 * decoding: set by libavformat, must not be modified by the caller.
786 AVPacket attached_pic;
789 * An array of side data that applies to the whole stream (i.e. the
790 * container does not allow it to change between packets).
792 * There may be no overlap between the side data in this array and side data
793 * in the packets. I.e. a given side data is either exported by the muxer
794 * (demuxing) / set by the caller (muxing) in this array, then it never
795 * appears in the packets, or the side data is exported / sent through
796 * the packets (always in the first packet where the value becomes known or
797 * changes), then it does not appear in this array.
799 * - demuxing: Set by libavformat when the stream is created.
800 * - muxing: May be set by the caller before avformat_write_header().
802 * Freed by libavformat in avformat_free_context().
804 AVPacketSideData *side_data;
806 * The number of elements in the AVStream.side_data array.
811 * Flags for the user to detect events happening on the stream. Flags must
812 * be cleared by the user once the event has been handled.
813 * A combination of AVSTREAM_EVENT_FLAG_*.
816 #define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
818 /*****************************************************************
819 * All fields below this line are not part of the public API. They
820 * may not be used outside of libavformat and can be changed and
822 * New public fields should be added right above.
823 *****************************************************************
827 * Stream information used internally by av_find_stream_info()
829 #define MAX_STD_TIMEBASES (60*12+5)
831 int nb_decoded_frames;
835 * Those are used for average framerate estimation.
837 int64_t fps_first_dts;
838 int fps_first_dts_idx;
839 int64_t fps_last_dts;
840 int fps_last_dts_idx;
844 int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
846 // Timestamp generation support:
850 int last_IP_duration;
853 * Number of packets to buffer for codec probing
855 #define MAX_PROBE_PACKETS 2500
859 * Number of frames that have been demuxed during av_find_stream_info()
861 int codec_info_nb_frames;
863 /* av_read_frame() support */
864 enum AVStreamParseType need_parsing;
865 struct AVCodecParserContext *parser;
868 * last packet in packet_buffer for this stream when muxing.
870 struct AVPacketList *last_in_packet_buffer;
871 AVProbeData probe_data;
872 #define MAX_REORDER_DELAY 16
873 int64_t pts_buffer[MAX_REORDER_DELAY+1];
875 AVIndexEntry *index_entries; /**< Only used if the format does not
876 support seeking natively. */
877 int nb_index_entries;
878 unsigned int index_entries_allocated_size;
881 #define AV_PROGRAM_RUNNING 1
884 * New fields can be added to the end with minor version bumps.
885 * Removal, reordering and changes to existing fields require a major
887 * sizeof(AVProgram) must not be used outside libav*.
889 typedef struct AVProgram {
892 enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
893 unsigned int *stream_index;
894 unsigned int nb_stream_indexes;
895 AVDictionary *metadata;
898 #define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
899 (streams are added dynamically) */
901 typedef struct AVChapter {
902 int id; ///< unique ID to identify the chapter
903 AVRational time_base; ///< time base in which the start/end timestamps are specified
904 int64_t start, end; ///< chapter start/end time in time_base units
905 AVDictionary *metadata;
908 typedef struct AVFormatInternal AVFormatInternal;
911 * Format I/O context.
912 * New fields can be added to the end with minor version bumps.
913 * Removal, reordering and changes to existing fields require a major
915 * sizeof(AVFormatContext) must not be used outside libav*, use
916 * avformat_alloc_context() to create an AVFormatContext.
918 typedef struct AVFormatContext {
920 * A class for logging and @ref avoptions. Set by avformat_alloc_context().
921 * Exports (de)muxer private options if they exist.
923 const AVClass *av_class;
926 * The input container format.
928 * Demuxing only, set by avformat_open_input().
930 struct AVInputFormat *iformat;
933 * The output container format.
935 * Muxing only, must be set by the caller before avformat_write_header().
937 struct AVOutputFormat *oformat;
940 * Format private data. This is an AVOptions-enabled struct
941 * if and only if iformat/oformat.priv_class is not NULL.
943 * - muxing: set by avformat_write_header()
944 * - demuxing: set by avformat_open_input()
951 * - demuxing: either set by the user before avformat_open_input() (then
952 * the user must close it manually) or set by avformat_open_input().
953 * - muxing: set by the user before avformat_write_header(). The caller must
954 * take care of closing / freeing the IO context.
956 * Do NOT set this field if AVFMT_NOFILE flag is set in
957 * iformat/oformat.flags. In such a case, the (de)muxer will handle
958 * I/O in some other way and this field will be NULL.
964 * Flags signalling stream properties. A combination of AVFMTCTX_*.
965 * Set by libavformat.
970 * Number of elements in AVFormatContext.streams.
972 * Set by avformat_new_stream(), must not be modified by any other code.
974 unsigned int nb_streams;
976 * A list of all streams in the file. New streams are created with
977 * avformat_new_stream().
979 * - demuxing: streams are created by libavformat in avformat_open_input().
980 * If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
981 * appear in av_read_frame().
982 * - muxing: streams are created by the user before avformat_write_header().
984 * Freed by libavformat in avformat_free_context().
989 * input or output filename
991 * - demuxing: set by avformat_open_input()
992 * - muxing: may be set by the caller before avformat_write_header()
997 * Position of the first frame of the component, in
998 * AV_TIME_BASE fractional seconds. NEVER set this value directly:
999 * It is deduced from the AVStream values.
1001 * Demuxing only, set by libavformat.
1006 * Duration of the stream, in AV_TIME_BASE fractional
1007 * seconds. Only set this value if you know none of the individual stream
1008 * durations and also do not set any of them. This is deduced from the
1009 * AVStream values if not set.
1011 * Demuxing only, set by libavformat.
1016 * Total stream bitrate in bit/s, 0 if not
1017 * available. Never set it directly if the file_size and the
1018 * duration are known as Libav can compute it automatically.
1022 unsigned int packet_size;
1026 * Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
1027 * Set by the user before avformat_open_input() / avformat_write_header().
1030 #define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
1031 #define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
1032 #define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
1033 #define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
1034 #define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container
1035 #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
1036 #define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
1037 #define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
1038 #define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
1039 #define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
1041 * When muxing, try to avoid writing any random/volatile data to the output.
1042 * This includes any random IDs, real-time timestamps/dates, muxer version, etc.
1044 * This flag is mainly intended for testing.
1046 #define AVFMT_FLAG_BITEXACT 0x0400
1049 * Maximum size of the data read from input for determining
1050 * the input container format.
1051 * Demuxing only, set by the caller before avformat_open_input().
1053 unsigned int probesize;
1056 * Maximum duration (in AV_TIME_BASE units) of the data read
1057 * from input in avformat_find_stream_info().
1058 * Demuxing only, set by the caller before avformat_find_stream_info().
1060 int max_analyze_duration;
1065 unsigned int nb_programs;
1066 AVProgram **programs;
1069 * Forced video codec_id.
1070 * Demuxing: Set by user.
1072 enum AVCodecID video_codec_id;
1075 * Forced audio codec_id.
1076 * Demuxing: Set by user.
1078 enum AVCodecID audio_codec_id;
1081 * Forced subtitle codec_id.
1082 * Demuxing: Set by user.
1084 enum AVCodecID subtitle_codec_id;
1087 * Maximum amount of memory in bytes to use for the index of each stream.
1088 * If the index exceeds this size, entries will be discarded as
1089 * needed to maintain a smaller size. This can lead to slower or less
1090 * accurate seeking (depends on demuxer).
1091 * Demuxers for which a full in-memory index is mandatory will ignore
1094 * - demuxing: set by user
1096 unsigned int max_index_size;
1099 * Maximum amount of memory in bytes to use for buffering frames
1100 * obtained from realtime capture devices.
1102 unsigned int max_picture_buffer;
1105 * Number of chapters in AVChapter array.
1106 * When muxing, chapters are normally written in the file header,
1107 * so nb_chapters should normally be initialized before write_header
1108 * is called. Some muxers (e.g. mov and mkv) can also write chapters
1109 * in the trailer. To write chapters in the trailer, nb_chapters
1110 * must be zero when write_header is called and non-zero when
1111 * write_trailer is called.
1112 * - muxing: set by user
1113 * - demuxing: set by libavformat
1115 unsigned int nb_chapters;
1116 AVChapter **chapters;
1119 * Metadata that applies to the whole file.
1121 * - demuxing: set by libavformat in avformat_open_input()
1122 * - muxing: may be set by the caller before avformat_write_header()
1124 * Freed by libavformat in avformat_free_context().
1126 AVDictionary *metadata;
1129 * Start time of the stream in real world time, in microseconds
1130 * since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1131 * stream was captured at this real world time.
1132 * Muxing only, set by the caller before avformat_write_header().
1134 int64_t start_time_realtime;
1137 * The number of frames used for determining the framerate in
1138 * avformat_find_stream_info().
1139 * Demuxing only, set by the caller before avformat_find_stream_info().
1144 * Error recognition; higher values will detect more errors but may
1145 * misdetect some more or less valid parts as errors.
1146 * Demuxing only, set by the caller before avformat_open_input().
1148 int error_recognition;
1151 * Custom interrupt callbacks for the I/O layer.
1153 * demuxing: set by the user before avformat_open_input().
1154 * muxing: set by the user before avformat_write_header()
1155 * (mainly useful for AVFMT_NOFILE formats). The callback
1156 * should also be passed to avio_open2() if it's used to
1159 AVIOInterruptCB interrupt_callback;
1162 * Flags to enable debugging.
1165 #define FF_FDEBUG_TS 0x0001
1168 * Maximum buffering duration for interleaving.
1170 * To ensure all the streams are interleaved correctly,
1171 * av_interleaved_write_frame() will wait until it has at least one packet
1172 * for each stream before actually writing any packets to the output file.
1173 * When some streams are "sparse" (i.e. there are large gaps between
1174 * successive packets), this can result in excessive buffering.
1176 * This field specifies the maximum difference between the timestamps of the
1177 * first and the last packet in the muxing queue, above which libavformat
1178 * will output a packet regardless of whether it has queued a packet for all
1181 * Muxing only, set by the caller before avformat_write_header().
1183 int64_t max_interleave_delta;
1186 * Allow non-standard and experimental extension
1187 * @see AVCodecContext.strict_std_compliance
1189 int strict_std_compliance;
1192 * Flags for the user to detect events happening on the file. Flags must
1193 * be cleared by the user once the event has been handled.
1194 * A combination of AVFMT_EVENT_FLAG_*.
1197 #define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
1200 * Maximum number of packets to read while waiting for the first timestamp.
1206 * Avoid negative timestamps during muxing.
1207 * Any value of the AVFMT_AVOID_NEG_TS_* constants.
1208 * Note, this only works when using av_interleaved_write_frame.
1209 * - muxing: Set by user
1210 * - demuxing: unused
1212 int avoid_negative_ts;
1213 #define AVFMT_AVOID_NEG_TS_AUTO -1 ///< Enabled when required by target format
1214 #define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
1215 #define AVFMT_AVOID_NEG_TS_MAKE_ZERO 2 ///< Shift timestamps so that they start at 0
1218 * An opaque field for libavformat internal usage.
1219 * Must not be accessed in any way by callers.
1221 AVFormatInternal *internal;
1224 typedef struct AVPacketList {
1226 struct AVPacketList *next;
1231 * @defgroup lavf_core Core functions
1234 * Functions for querying libavformat capabilities, allocating core structures,
1240 * Return the LIBAVFORMAT_VERSION_INT constant.
1242 unsigned avformat_version(void);
1245 * Return the libavformat build-time configuration.
1247 const char *avformat_configuration(void);
1250 * Return the libavformat license.
1252 const char *avformat_license(void);
1255 * Initialize libavformat and register all the muxers, demuxers and
1256 * protocols. If you do not call this function, then you can select
1257 * exactly which formats you want to support.
1259 * @see av_register_input_format()
1260 * @see av_register_output_format()
1261 * @see av_register_protocol()
1263 void av_register_all(void);
1265 void av_register_input_format(AVInputFormat *format);
1266 void av_register_output_format(AVOutputFormat *format);
1269 * Do global initialization of network components. This is optional,
1270 * but recommended, since it avoids the overhead of implicitly
1271 * doing the setup for each session.
1273 * Calling this function will become mandatory if using network
1274 * protocols at some major version bump.
1276 int avformat_network_init(void);
1279 * Undo the initialization done by avformat_network_init.
1281 int avformat_network_deinit(void);
1284 * If f is NULL, returns the first registered input format,
1285 * if f is non-NULL, returns the next registered input format after f
1286 * or NULL if f is the last one.
1288 AVInputFormat *av_iformat_next(const AVInputFormat *f);
1291 * If f is NULL, returns the first registered output format,
1292 * if f is non-NULL, returns the next registered output format after f
1293 * or NULL if f is the last one.
1295 AVOutputFormat *av_oformat_next(const AVOutputFormat *f);
1298 * Allocate an AVFormatContext.
1299 * avformat_free_context() can be used to free the context and everything
1300 * allocated by the framework within it.
1302 AVFormatContext *avformat_alloc_context(void);
1305 * Free an AVFormatContext and all its streams.
1306 * @param s context to free
1308 void avformat_free_context(AVFormatContext *s);
1311 * Get the AVClass for AVFormatContext. It can be used in combination with
1312 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
1314 * @see av_opt_find().
1316 const AVClass *avformat_get_class(void);
1319 * Add a new stream to a media file.
1321 * When demuxing, it is called by the demuxer in read_header(). If the
1322 * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
1323 * be called in read_packet().
1325 * When muxing, should be called by the user before avformat_write_header().
1327 * @param s media file handle
1328 * @param c If non-NULL, the AVCodecContext corresponding to the new stream
1329 * will be initialized to use this codec. This is needed for e.g. codec-specific
1330 * defaults to be set, so codec should be provided if it is known.
1332 * @return newly created stream or NULL on error.
1334 AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c);
1337 * Get side information from stream.
1339 * @param stream stream
1340 * @param type desired side information type
1341 * @param size pointer for side information size to store (optional)
1342 * @return pointer to data if present or NULL otherwise
1344 uint8_t *av_stream_get_side_data(AVStream *stream,
1345 enum AVPacketSideDataType type, int *size);
1347 AVProgram *av_new_program(AVFormatContext *s, int id);
1355 * @addtogroup lavf_decoding
1360 * Find AVInputFormat based on the short name of the input format.
1362 AVInputFormat *av_find_input_format(const char *short_name);
1365 * Guess the file format.
1367 * @param pd data to be probed
1368 * @param is_opened Whether the file is already opened; determines whether
1369 * demuxers with or without AVFMT_NOFILE are probed.
1371 AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened);
1374 * Guess the file format.
1376 * @param pd data to be probed
1377 * @param is_opened Whether the file is already opened; determines whether
1378 * demuxers with or without AVFMT_NOFILE are probed.
1379 * @param score_max A probe score larger that this is required to accept a
1380 * detection, the variable is set to the actual detection
1382 * If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
1383 * to retry with a larger probe buffer.
1385 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max);
1388 * Probe a bytestream to determine the input format. Each time a probe returns
1389 * with a score that is too low, the probe buffer size is increased and another
1390 * attempt is made. When the maximum probe size is reached, the input format
1391 * with the highest score is returned.
1393 * @param pb the bytestream to probe
1394 * @param fmt the input format is put here
1395 * @param filename the filename of the stream
1396 * @param logctx the log context
1397 * @param offset the offset within the bytestream to probe from
1398 * @param max_probe_size the maximum probe buffer size (zero for default)
1399 * @return 0 in case of success, a negative value corresponding to an
1400 * AVERROR code otherwise
1402 int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
1403 const char *filename, void *logctx,
1404 unsigned int offset, unsigned int max_probe_size);
1407 * Open an input stream and read the header. The codecs are not opened.
1408 * The stream must be closed with avformat_close_input().
1410 * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
1411 * May be a pointer to NULL, in which case an AVFormatContext is allocated by this
1412 * function and written into ps.
1413 * Note that a user-supplied AVFormatContext will be freed on failure.
1414 * @param filename Name of the stream to open.
1415 * @param fmt If non-NULL, this parameter forces a specific input format.
1416 * Otherwise the format is autodetected.
1417 * @param options A dictionary filled with AVFormatContext and demuxer-private options.
1418 * On return this parameter will be destroyed and replaced with a dict containing
1419 * options that were not found. May be NULL.
1421 * @return 0 on success, a negative AVERROR on failure.
1423 * @note If you want to use custom IO, preallocate the format context and set its pb field.
1425 int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options);
1428 * Read packets of a media file to get stream information. This
1429 * is useful for file formats with no headers such as MPEG. This
1430 * function also computes the real framerate in case of MPEG-2 repeat
1432 * The logical file position is not changed by this function;
1433 * examined packets may be buffered for later processing.
1435 * @param ic media file handle
1436 * @param options If non-NULL, an ic.nb_streams long array of pointers to
1437 * dictionaries, where i-th member contains options for
1438 * codec corresponding to i-th stream.
1439 * On return each dictionary will be filled with options that were not found.
1440 * @return >=0 if OK, AVERROR_xxx on error
1442 * @note this function isn't guaranteed to open all the codecs, so
1443 * options being non-empty at return is a perfectly normal behavior.
1445 * @todo Let the user decide somehow what information is needed so that
1446 * we do not waste time getting stuff the user does not need.
1448 int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options);
1451 * Find the "best" stream in the file.
1452 * The best stream is determined according to various heuristics as the most
1453 * likely to be what the user expects.
1454 * If the decoder parameter is non-NULL, av_find_best_stream will find the
1455 * default decoder for the stream's codec; streams for which no decoder can
1456 * be found are ignored.
1458 * @param ic media file handle
1459 * @param type stream type: video, audio, subtitles, etc.
1460 * @param wanted_stream_nb user-requested stream number,
1461 * or -1 for automatic selection
1462 * @param related_stream try to find a stream related (eg. in the same
1463 * program) to this one, or -1 if none
1464 * @param decoder_ret if non-NULL, returns the decoder for the
1466 * @param flags flags; none are currently defined
1467 * @return the non-negative stream number in case of success,
1468 * AVERROR_STREAM_NOT_FOUND if no stream with the requested type
1470 * AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
1471 * @note If av_find_best_stream returns successfully and decoder_ret is not
1472 * NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
1474 int av_find_best_stream(AVFormatContext *ic,
1475 enum AVMediaType type,
1476 int wanted_stream_nb,
1478 AVCodec **decoder_ret,
1482 * Return the next frame of a stream.
1483 * This function returns what is stored in the file, and does not validate
1484 * that what is there are valid frames for the decoder. It will split what is
1485 * stored in the file into frames and return one for each call. It will not
1486 * omit invalid data between valid frames so as to give the decoder the maximum
1487 * information possible for decoding.
1489 * If pkt->buf is NULL, then the packet is valid until the next
1490 * av_read_frame() or until avformat_close_input(). Otherwise the packet
1491 * is valid indefinitely. In both cases the packet must be freed with
1492 * av_free_packet when it is no longer needed. For video, the packet contains
1493 * exactly one frame. For audio, it contains an integer number of frames if each
1494 * frame has a known fixed size (e.g. PCM or ADPCM data). If the audio frames
1495 * have a variable size (e.g. MPEG audio), then it contains one frame.
1497 * pkt->pts, pkt->dts and pkt->duration are always set to correct
1498 * values in AVStream.time_base units (and guessed if the format cannot
1499 * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
1500 * has B-frames, so it is better to rely on pkt->dts if you do not
1501 * decompress the payload.
1503 * @return 0 if OK, < 0 on error or end of file
1505 int av_read_frame(AVFormatContext *s, AVPacket *pkt);
1508 * Seek to the keyframe at timestamp.
1509 * 'timestamp' in 'stream_index'.
1511 * @param s media file handle
1512 * @param stream_index If stream_index is (-1), a default
1513 * stream is selected, and timestamp is automatically converted
1514 * from AV_TIME_BASE units to the stream specific time_base.
1515 * @param timestamp Timestamp in AVStream.time_base units
1516 * or, if no stream is specified, in AV_TIME_BASE units.
1517 * @param flags flags which select direction and seeking mode
1518 * @return >= 0 on success
1520 int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
1524 * Seek to timestamp ts.
1525 * Seeking will be done so that the point from which all active streams
1526 * can be presented successfully will be closest to ts and within min/max_ts.
1527 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
1529 * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
1530 * are the file position (this may not be supported by all demuxers).
1531 * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
1532 * in the stream with stream_index (this may not be supported by all demuxers).
1533 * Otherwise all timestamps are in units of the stream selected by stream_index
1534 * or if stream_index is -1, in AV_TIME_BASE units.
1535 * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
1536 * keyframes (this may not be supported by all demuxers).
1538 * @param s media file handle
1539 * @param stream_index index of the stream which is used as time base reference
1540 * @param min_ts smallest acceptable timestamp
1541 * @param ts target timestamp
1542 * @param max_ts largest acceptable timestamp
1543 * @param flags flags
1544 * @return >=0 on success, error code otherwise
1546 * @note This is part of the new seek API which is still under construction.
1547 * Thus do not use this yet. It may change at any time, do not expect
1548 * ABI compatibility yet!
1550 int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
1553 * Start playing a network-based stream (e.g. RTSP stream) at the
1556 int av_read_play(AVFormatContext *s);
1559 * Pause a network-based stream (e.g. RTSP stream).
1561 * Use av_read_play() to resume it.
1563 int av_read_pause(AVFormatContext *s);
1566 * Close an opened input AVFormatContext. Free it and all its contents
1567 * and set *s to NULL.
1569 void avformat_close_input(AVFormatContext **s);
1574 #define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
1575 #define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
1576 #define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
1577 #define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
1580 * @addtogroup lavf_encoding
1584 * Allocate the stream private data and write the stream header to
1585 * an output media file.
1587 * @param s Media file handle, must be allocated with avformat_alloc_context().
1588 * Its oformat field must be set to the desired output format;
1589 * Its pb field must be set to an already opened AVIOContext.
1590 * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
1591 * On return this parameter will be destroyed and replaced with a dict containing
1592 * options that were not found. May be NULL.
1594 * @return 0 on success, negative AVERROR on failure.
1596 * @see av_opt_find, av_dict_set, avio_open, av_oformat_next.
1598 int avformat_write_header(AVFormatContext *s, AVDictionary **options);
1601 * Write a packet to an output media file.
1603 * This function passes the packet directly to the muxer, without any buffering
1604 * or reordering. The caller is responsible for correctly interleaving the
1605 * packets if the format requires it. Callers that want libavformat to handle
1606 * the interleaving should call av_interleaved_write_frame() instead of this
1609 * @param s media file handle
1610 * @param pkt The packet containing the data to be written. Note that unlike
1611 * av_interleaved_write_frame(), this function does not take
1612 * ownership of the packet passed to it (though some muxers may make
1613 * an internal reference to the input packet).
1615 * This parameter can be NULL (at any time, not just at the end), in
1616 * order to immediately flush data buffered within the muxer, for
1617 * muxers that buffer up data internally before writing it to the
1620 * Packet's @ref AVPacket.stream_index "stream_index" field must be
1621 * set to the index of the corresponding stream in @ref
1622 * AVFormatContext.streams "s->streams". It is very strongly
1623 * recommended that timing information (@ref AVPacket.pts "pts", @ref
1624 * AVPacket.dts "dts", @ref AVPacket.duration "duration") is set to
1626 * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
1628 * @see av_interleaved_write_frame()
1630 int av_write_frame(AVFormatContext *s, AVPacket *pkt);
1633 * Write a packet to an output media file ensuring correct interleaving.
1635 * This function will buffer the packets internally as needed to make sure the
1636 * packets in the output file are properly interleaved in the order of
1637 * increasing dts. Callers doing their own interleaving should call
1638 * av_write_frame() instead of this function.
1640 * @param s media file handle
1641 * @param pkt The packet containing the data to be written.
1643 * If the packet is reference-counted, this function will take
1644 * ownership of this reference and unreference it later when it sees
1646 * The caller must not access the data through this reference after
1647 * this function returns. If the packet is not reference-counted,
1648 * libavformat will make a copy.
1650 * This parameter can be NULL (at any time, not just at the end), to
1651 * flush the interleaving queues.
1653 * Packet's @ref AVPacket.stream_index "stream_index" field must be
1654 * set to the index of the corresponding stream in @ref
1655 * AVFormatContext.streams "s->streams". It is very strongly
1656 * recommended that timing information (@ref AVPacket.pts "pts", @ref
1657 * AVPacket.dts "dts", @ref AVPacket.duration "duration") is set to
1660 * @return 0 on success, a negative AVERROR on error. Libavformat will always
1661 * take care of freeing the packet, even if this function fails.
1663 * @see av_write_frame(), AVFormatContext.max_interleave_delta
1665 int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
1668 * Write the stream trailer to an output media file and free the
1669 * file private data.
1671 * May only be called after a successful call to avformat_write_header.
1673 * @param s media file handle
1674 * @return 0 if OK, AVERROR_xxx on error
1676 int av_write_trailer(AVFormatContext *s);
1679 * Return the output format in the list of registered output formats
1680 * which best matches the provided parameters, or return NULL if
1681 * there is no match.
1683 * @param short_name if non-NULL checks if short_name matches with the
1684 * names of the registered formats
1685 * @param filename if non-NULL checks if filename terminates with the
1686 * extensions of the registered formats
1687 * @param mime_type if non-NULL checks if mime_type matches with the
1688 * MIME type of the registered formats
1690 AVOutputFormat *av_guess_format(const char *short_name,
1691 const char *filename,
1692 const char *mime_type);
1695 * Guess the codec ID based upon muxer and filename.
1697 enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
1698 const char *filename, const char *mime_type,
1699 enum AVMediaType type);
1707 * @defgroup lavf_misc Utility functions
1711 * Miscellaneous utility functions related to both muxing and demuxing
1716 * Send a nice hexadecimal dump of a buffer to the specified file stream.
1718 * @param f The file stream pointer where the dump should be sent to.
1720 * @param size buffer size
1722 * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
1724 void av_hex_dump(FILE *f, const uint8_t *buf, int size);
1727 * Send a nice hexadecimal dump of a buffer to the log.
1729 * @param avcl A pointer to an arbitrary struct of which the first field is a
1730 * pointer to an AVClass struct.
1731 * @param level The importance level of the message, lower values signifying
1732 * higher importance.
1734 * @param size buffer size
1736 * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
1738 void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
1741 * Send a nice dump of a packet to the specified file stream.
1743 * @param f The file stream pointer where the dump should be sent to.
1744 * @param pkt packet to dump
1745 * @param dump_payload True if the payload must be displayed, too.
1746 * @param st AVStream that the packet belongs to
1748 void av_pkt_dump2(FILE *f, AVPacket *pkt, int dump_payload, AVStream *st);
1752 * Send a nice dump of a packet to the log.
1754 * @param avcl A pointer to an arbitrary struct of which the first field is a
1755 * pointer to an AVClass struct.
1756 * @param level The importance level of the message, lower values signifying
1757 * higher importance.
1758 * @param pkt packet to dump
1759 * @param dump_payload True if the payload must be displayed, too.
1760 * @param st AVStream that the packet belongs to
1762 void av_pkt_dump_log2(void *avcl, int level, AVPacket *pkt, int dump_payload,
1766 * Get the AVCodecID for the given codec tag tag.
1767 * If no codec id is found returns AV_CODEC_ID_NONE.
1769 * @param tags list of supported codec_id-codec_tag pairs, as stored
1770 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
1771 * @param tag codec tag to match to a codec ID
1773 enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
1776 * Get the codec tag for the given codec id id.
1777 * If no codec tag is found returns 0.
1779 * @param tags list of supported codec_id-codec_tag pairs, as stored
1780 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
1781 * @param id codec ID to match to a codec tag
1783 unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id);
1785 int av_find_default_stream_index(AVFormatContext *s);
1788 * Get the index for a specific timestamp.
1790 * @param st stream that the timestamp belongs to
1791 * @param timestamp timestamp to retrieve the index for
1792 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
1793 * to the timestamp which is <= the requested one, if backward
1794 * is 0, then it will be >=
1795 * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
1796 * @return < 0 if no such timestamp could be found
1798 int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
1801 * Add an index entry into a sorted list. Update the entry if the list
1802 * already contains it.
1804 * @param timestamp timestamp in the time base of the given stream
1806 int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
1807 int size, int distance, int flags);
1811 * Split a URL string into components.
1813 * The pointers to buffers for storing individual components may be null,
1814 * in order to ignore that component. Buffers for components not found are
1815 * set to empty strings. If the port is not found, it is set to a negative
1818 * @param proto the buffer for the protocol
1819 * @param proto_size the size of the proto buffer
1820 * @param authorization the buffer for the authorization
1821 * @param authorization_size the size of the authorization buffer
1822 * @param hostname the buffer for the host name
1823 * @param hostname_size the size of the hostname buffer
1824 * @param port_ptr a pointer to store the port number in
1825 * @param path the buffer for the path
1826 * @param path_size the size of the path buffer
1827 * @param url the URL to split
1829 void av_url_split(char *proto, int proto_size,
1830 char *authorization, int authorization_size,
1831 char *hostname, int hostname_size,
1833 char *path, int path_size,
1838 * Print detailed information about the input or output format, such as
1839 * duration, bitrate, streams, container, programs, metadata, side data,
1840 * codec and time base.
1842 * @param ic the context to analyze
1843 * @param index the index to print, if you have multiple inputs or outputs
1844 * @param url the URL to print, such as source or destination file
1845 * @param is_output whether the context is input or ouput
1847 void av_dump_format(AVFormatContext *ic,
1853 * Return in 'buf' the path with '%d' replaced by a number.
1855 * Also handles the '%0nd' format where 'n' is the total number
1856 * of digits and '%%'.
1858 * @param buf destination buffer
1859 * @param buf_size destination buffer size
1860 * @param path numbered sequence string
1861 * @param number frame number
1862 * @return 0 if OK, -1 on format error
1864 int av_get_frame_filename(char *buf, int buf_size,
1865 const char *path, int number);
1868 * Check whether filename actually is a numbered sequence generator.
1870 * @param filename possible numbered sequence string
1871 * @return 1 if a valid numbered sequence string, 0 otherwise
1873 int av_filename_number_test(const char *filename);
1876 * Generate an SDP for an RTP session.
1878 * Note, this overwrites the id values of AVStreams in the muxer contexts
1879 * for getting unique dynamic payload types.
1881 * @param ac array of AVFormatContexts describing the RTP streams. If the
1882 * array is composed by only one context, such context can contain
1883 * multiple AVStreams (one AVStream per RTP stream). Otherwise,
1884 * all the contexts in the array (an AVCodecContext per RTP stream)
1885 * must contain only one AVStream.
1886 * @param n_files number of AVCodecContexts contained in ac
1887 * @param buf buffer where the SDP will be stored (must be allocated by
1889 * @param size the size of the buffer
1890 * @return 0 if OK, AVERROR_xxx on error
1892 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
1895 * Return a positive value if the given filename has one of the given
1896 * extensions, 0 otherwise.
1898 * @param filename file name to check against the given extensions
1899 * @param extensions a comma-separated list of filename extensions
1901 int av_match_ext(const char *filename, const char *extensions);
1904 * Test if the given container can store a codec.
1906 * @param ofmt container to check for compatibility
1907 * @param codec_id codec to potentially store in container
1908 * @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
1910 * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
1911 * A negative number if this information is not available.
1913 int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id,
1914 int std_compliance);
1917 * @defgroup riff_fourcc RIFF FourCCs
1919 * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
1920 * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
1923 * uint32_t tag = MKTAG('H', '2', '6', '4');
1924 * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
1925 * enum AVCodecID id = av_codec_get_id(table, tag);
1929 * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
1931 const struct AVCodecTag *avformat_get_riff_video_tags(void);
1933 * @return the table mapping RIFF FourCCs for audio to AVCodecID.
1935 const struct AVCodecTag *avformat_get_riff_audio_tags(void);
1944 #endif /* AVFORMAT_AVFORMAT_H */