lavf: add an AVStream field for exporting stream-global side data
[libav.git] / libavformat / avformat.h
1 /*
2 * copyright (c) 2001 Fabrice Bellard
3 *
4 * This file is part of Libav.
5 *
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.
10 *
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.
15 *
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
19 */
20
21 #ifndef AVFORMAT_AVFORMAT_H
22 #define AVFORMAT_AVFORMAT_H
23
24 /**
25 * @file
26 * @ingroup libavf
27 * Main libavformat public API header
28 */
29
30 /**
31 * @defgroup libavf I/O and Muxing/Demuxing Library
32 * @{
33 *
34 * Libavformat (lavf) is a library for dealing with various media container
35 * formats. Its main two purposes are demuxing - i.e. splitting a media file
36 * into component streams, and the reverse process of muxing - writing supplied
37 * data in a specified container format. It also has an @ref lavf_io
38 * "I/O module" which supports a number of protocols for accessing the data (e.g.
39 * file, tcp, http and others). 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().
43 *
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.
50 *
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).
57 *
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).
68 *
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.
80 *
81 * @defgroup lavf_decoding Demuxing
82 * @{
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
88 * cleanup.
89 *
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:
93 * @code
94 * const char *url = "in.mp3";
95 * AVFormatContext *s = NULL;
96 * int ret = avformat_open_input(&s, url, NULL, NULL);
97 * if (ret < 0)
98 * abort();
99 * @endcode
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.
106 *
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.
114 *
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:
119 * @code
120 * AVDictionary *options = NULL;
121 * av_dict_set(&options, "video_size", "640x480", 0);
122 * av_dict_set(&options, "pixel_format", "rgb24", 0);
123 *
124 * if (avformat_open_input(&s, url, NULL, &options) < 0)
125 * abort();
126 * av_dict_free(&options);
127 * @endcode
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
135 * wishes, e.g.
136 * @code
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);
140 * abort();
141 * }
142 * @endcode
143 *
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.
146 *
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.
154 *
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.
160 *
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
167 * of it.
168 * In both cases, the packet must be freed with av_free_packet() when it is no
169 * longer needed.
170 *
171 * @section lavf_decoding_seek Seeking
172 * @}
173 *
174 * @defgroup lavf_encoding Muxing
175 * @{
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.
178 *
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.
182 *
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:
186 *
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 AVCodecContext.time_base "codec 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
200 * described later).
201 * - The caller may fill in additional information, such as @ref
202 * AVFormatContext.metadata "global" or @ref AVStream.metadata "per-stream"
203 * metadata, @ref AVFormatContext.chapters "chapters", @ref
204 * AVFormatContext.programs "programs", etc. as described in the
205 * AVFormatContext documentation. Whether such information will actually be
206 * stored in the output depends on what the container format and the muxer
207 * support.
208 *
209 * When the muxing context is fully set up, the caller must call
210 * avformat_write_header() to initialize the muxer internals and write the file
211 * header. Whether anything actually is written to the IO context at this step
212 * depends on the muxer, but this function must always be called. Any muxer
213 * private options must be passed in the options parameter to this function.
214 *
215 * The data is then sent to the muxer by repeatedly calling av_write_frame() or
216 * av_interleaved_write_frame() (consult those functions' documentation for
217 * discussion on the difference between them; only one of them may be used with
218 * a single muxing context, they should not be mixed). Do note that the timing
219 * information on the packets sent to the muxer must be in the corresponding
220 * AVStream's timebase. That timebase is set by the muxer (in the
221 * avformat_write_header() step) and may be different from the timebase the
222 * caller set on the codec context.
223 *
224 * Once all the data has been written, the caller must call av_write_trailer()
225 * to flush any buffered packets and finalize the output file, then close the IO
226 * context (if any) and finally free the muxing context with
227 * avformat_free_context().
228 * @}
229 *
230 * @defgroup lavf_io I/O Read/Write
231 * @{
232 * @}
233 *
234 * @defgroup lavf_codec Demuxers
235 * @{
236 * @defgroup lavf_codec_native Native Demuxers
237 * @{
238 * @}
239 * @defgroup lavf_codec_wrappers External library wrappers
240 * @{
241 * @}
242 * @}
243 * @defgroup lavf_protos I/O Protocols
244 * @{
245 * @}
246 * @defgroup lavf_internal Internal
247 * @{
248 * @}
249 * @}
250 *
251 */
252
253 #include <time.h>
254 #include <stdio.h> /* FILE */
255 #include "libavcodec/avcodec.h"
256 #include "libavutil/dict.h"
257 #include "libavutil/log.h"
258
259 #include "avio.h"
260 #include "libavformat/version.h"
261
262 struct AVFormatContext;
263
264
265 /**
266 * @defgroup metadata_api Public Metadata API
267 * @{
268 * @ingroup libavf
269 * The metadata API allows libavformat to export metadata tags to a client
270 * application when demuxing. Conversely it allows a client application to
271 * set metadata when muxing.
272 *
273 * Metadata is exported or set as pairs of key/value strings in the 'metadata'
274 * fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
275 * using the @ref lavu_dict "AVDictionary" API. Like all strings in Libav,
276 * metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
277 * exported by demuxers isn't checked to be valid UTF-8 in most cases.
278 *
279 * Important concepts to keep in mind:
280 * - Keys are unique; there can never be 2 tags with the same key. This is
281 * also meant semantically, i.e., a demuxer should not knowingly produce
282 * several keys that are literally different but semantically identical.
283 * E.g., key=Author5, key=Author6. In this example, all authors must be
284 * placed in the same tag.
285 * - Metadata is flat, not hierarchical; there are no subtags. If you
286 * want to store, e.g., the email address of the child of producer Alice
287 * and actor Bob, that could have key=alice_and_bobs_childs_email_address.
288 * - Several modifiers can be applied to the tag name. This is done by
289 * appending a dash character ('-') and the modifier name in the order
290 * they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
291 * - language -- a tag whose value is localized for a particular language
292 * is appended with the ISO 639-2/B 3-letter language code.
293 * For example: Author-ger=Michael, Author-eng=Mike
294 * The original/default language is in the unqualified "Author" tag.
295 * A demuxer should set a default if it sets any translated tag.
296 * - sorting -- a modified version of a tag that should be used for
297 * sorting will have '-sort' appended. E.g. artist="The Beatles",
298 * artist-sort="Beatles, The".
299 *
300 * - Demuxers attempt to export metadata in a generic format, however tags
301 * with no generic equivalents are left as they are stored in the container.
302 * Follows a list of generic tag names:
303 *
304 @verbatim
305 album -- name of the set this work belongs to
306 album_artist -- main creator of the set/album, if different from artist.
307 e.g. "Various Artists" for compilation albums.
308 artist -- main creator of the work
309 comment -- any additional description of the file.
310 composer -- who composed the work, if different from artist.
311 copyright -- name of copyright holder.
312 creation_time-- date when the file was created, preferably in ISO 8601.
313 date -- date when the work was created, preferably in ISO 8601.
314 disc -- number of a subset, e.g. disc in a multi-disc collection.
315 encoder -- name/settings of the software/hardware that produced the file.
316 encoded_by -- person/group who created the file.
317 filename -- original name of the file.
318 genre -- <self-evident>.
319 language -- main language in which the work is performed, preferably
320 in ISO 639-2 format. Multiple languages can be specified by
321 separating them with commas.
322 performer -- artist who performed the work, if different from artist.
323 E.g for "Also sprach Zarathustra", artist would be "Richard
324 Strauss" and performer "London Philharmonic Orchestra".
325 publisher -- name of the label/publisher.
326 service_name -- name of the service in broadcasting (channel name).
327 service_provider -- name of the service provider in broadcasting.
328 title -- name of the work.
329 track -- number of this work in the set, can be in form current/total.
330 variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
331 @endverbatim
332 *
333 * Look in the examples section for an application example how to use the Metadata API.
334 *
335 * @}
336 */
337
338 /* packet functions */
339
340
341 /**
342 * Allocate and read the payload of a packet and initialize its
343 * fields with default values.
344 *
345 * @param s associated IO context
346 * @param pkt packet
347 * @param size desired payload size
348 * @return >0 (read size) if OK, AVERROR_xxx otherwise
349 */
350 int av_get_packet(AVIOContext *s, AVPacket *pkt, int size);
351
352
353 /**
354 * Read data and append it to the current content of the AVPacket.
355 * If pkt->size is 0 this is identical to av_get_packet.
356 * Note that this uses av_grow_packet and thus involves a realloc
357 * which is inefficient. Thus this function should only be used
358 * when there is no reasonable way to know (an upper bound of)
359 * the final size.
360 *
361 * @param s associated IO context
362 * @param pkt packet
363 * @param size amount of data to read
364 * @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
365 * will not be lost even if an error occurs.
366 */
367 int av_append_packet(AVIOContext *s, AVPacket *pkt, int size);
368
369 /*************************************************/
370 /* fractional numbers for exact pts handling */
371
372 /**
373 * The exact value of the fractional number is: 'val + num / den'.
374 * num is assumed to be 0 <= num < den.
375 */
376 typedef struct AVFrac {
377 int64_t val, num, den;
378 } AVFrac;
379
380 /*************************************************/
381 /* input/output formats */
382
383 struct AVCodecTag;
384
385 /**
386 * This structure contains the data a format has to probe a file.
387 */
388 typedef struct AVProbeData {
389 const char *filename;
390 unsigned char *buf; /**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */
391 int buf_size; /**< Size of buf except extra allocated bytes */
392 } AVProbeData;
393
394 #define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
395 #define AVPROBE_SCORE_MAX 100 ///< maximum score
396
397 #define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
398
399 /// Demuxer will use avio_open, no opened file should be provided by the caller.
400 #define AVFMT_NOFILE 0x0001
401 #define AVFMT_NEEDNUMBER 0x0002 /**< Needs '%d' in filename. */
402 #define AVFMT_SHOW_IDS 0x0008 /**< Show format stream IDs numbers. */
403 #define AVFMT_RAWPICTURE 0x0020 /**< Format wants AVPicture structure for
404 raw picture data. */
405 #define AVFMT_GLOBALHEADER 0x0040 /**< Format wants global header. */
406 #define AVFMT_NOTIMESTAMPS 0x0080 /**< Format does not need / have any timestamps. */
407 #define AVFMT_GENERIC_INDEX 0x0100 /**< Use generic index building code. */
408 #define AVFMT_TS_DISCONT 0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
409 #define AVFMT_VARIABLE_FPS 0x0400 /**< Format allows variable fps. */
410 #define AVFMT_NODIMENSIONS 0x0800 /**< Format does not need width/height */
411 #define AVFMT_NOSTREAMS 0x1000 /**< Format does not require any streams */
412 #define AVFMT_NOBINSEARCH 0x2000 /**< Format does not allow to fall back on binary search via read_timestamp */
413 #define AVFMT_NOGENSEARCH 0x4000 /**< Format does not allow to fall back on generic search */
414 #define AVFMT_NO_BYTE_SEEK 0x8000 /**< Format does not allow seeking by bytes */
415 #define AVFMT_ALLOW_FLUSH 0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
416 #define AVFMT_TS_NONSTRICT 0x20000 /**< Format does not require strictly
417 increasing timestamps, but they must
418 still be monotonic */
419 #define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative
420 timestamps. If not set the timestamp
421 will be shifted in av_write_frame and
422 av_interleaved_write_frame so they
423 start from 0. */
424
425 /**
426 * @addtogroup lavf_encoding
427 * @{
428 */
429 typedef struct AVOutputFormat {
430 const char *name;
431 /**
432 * Descriptive name for the format, meant to be more human-readable
433 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
434 * to define it.
435 */
436 const char *long_name;
437 const char *mime_type;
438 const char *extensions; /**< comma-separated filename extensions */
439 /* output support */
440 enum AVCodecID audio_codec; /**< default audio codec */
441 enum AVCodecID video_codec; /**< default video codec */
442 enum AVCodecID subtitle_codec; /**< default subtitle codec */
443 /**
444 * can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_RAWPICTURE,
445 * AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
446 * AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
447 * AVFMT_TS_NONSTRICT
448 */
449 int flags;
450
451 /**
452 * List of supported codec_id-codec_tag pairs, ordered by "better
453 * choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
454 */
455 const struct AVCodecTag * const *codec_tag;
456
457
458 const AVClass *priv_class; ///< AVClass for the private context
459
460 /*****************************************************************
461 * No fields below this line are part of the public API. They
462 * may not be used outside of libavformat and can be changed and
463 * removed at will.
464 * New public fields should be added right above.
465 *****************************************************************
466 */
467 struct AVOutputFormat *next;
468 /**
469 * size of private data so that it can be allocated in the wrapper
470 */
471 int priv_data_size;
472
473 int (*write_header)(struct AVFormatContext *);
474 /**
475 * Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,
476 * pkt can be NULL in order to flush data buffered in the muxer.
477 * When flushing, return 0 if there still is more data to flush,
478 * or 1 if everything was flushed and there is no more buffered
479 * data.
480 */
481 int (*write_packet)(struct AVFormatContext *, AVPacket *pkt);
482 int (*write_trailer)(struct AVFormatContext *);
483 /**
484 * Currently only used to set pixel format if not YUV420P.
485 */
486 int (*interleave_packet)(struct AVFormatContext *, AVPacket *out,
487 AVPacket *in, int flush);
488 /**
489 * Test if the given codec can be stored in this container.
490 *
491 * @return 1 if the codec is supported, 0 if it is not.
492 * A negative number if unknown.
493 */
494 int (*query_codec)(enum AVCodecID id, int std_compliance);
495 } AVOutputFormat;
496 /**
497 * @}
498 */
499
500 /**
501 * @addtogroup lavf_decoding
502 * @{
503 */
504 typedef struct AVInputFormat {
505 /**
506 * A comma separated list of short names for the format. New names
507 * may be appended with a minor bump.
508 */
509 const char *name;
510
511 /**
512 * Descriptive name for the format, meant to be more human-readable
513 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
514 * to define it.
515 */
516 const char *long_name;
517
518 /**
519 * Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
520 * AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
521 * AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK.
522 */
523 int flags;
524
525 /**
526 * If extensions are defined, then no probe is done. You should
527 * usually not use extension format guessing because it is not
528 * reliable enough
529 */
530 const char *extensions;
531
532 const struct AVCodecTag * const *codec_tag;
533
534 const AVClass *priv_class; ///< AVClass for the private context
535
536 /*****************************************************************
537 * No fields below this line are part of the public API. They
538 * may not be used outside of libavformat and can be changed and
539 * removed at will.
540 * New public fields should be added right above.
541 *****************************************************************
542 */
543 struct AVInputFormat *next;
544
545 /**
546 * Raw demuxers store their codec ID here.
547 */
548 int raw_codec_id;
549
550 /**
551 * Size of private data so that it can be allocated in the wrapper.
552 */
553 int priv_data_size;
554
555 /**
556 * Tell if a given file has a chance of being parsed as this format.
557 * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
558 * big so you do not have to check for that unless you need more.
559 */
560 int (*read_probe)(AVProbeData *);
561
562 /**
563 * Read the format header and initialize the AVFormatContext
564 * structure. Return 0 if OK. Only used in raw format right
565 * now. 'avformat_new_stream' should be called to create new streams.
566 */
567 int (*read_header)(struct AVFormatContext *);
568
569 /**
570 * Read one packet and put it in 'pkt'. pts and flags are also
571 * set. 'avformat_new_stream' can be called only if the flag
572 * AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
573 * background thread).
574 * @return 0 on success, < 0 on error.
575 * When returning an error, pkt must not have been allocated
576 * or must be freed before returning
577 */
578 int (*read_packet)(struct AVFormatContext *, AVPacket *pkt);
579
580 /**
581 * Close the stream. The AVFormatContext and AVStreams are not
582 * freed by this function
583 */
584 int (*read_close)(struct AVFormatContext *);
585
586 /**
587 * Seek to a given timestamp relative to the frames in
588 * stream component stream_index.
589 * @param stream_index Must not be -1.
590 * @param flags Selects which direction should be preferred if no exact
591 * match is available.
592 * @return >= 0 on success (but not necessarily the new offset)
593 */
594 int (*read_seek)(struct AVFormatContext *,
595 int stream_index, int64_t timestamp, int flags);
596
597 /**
598 * Get the next timestamp in stream[stream_index].time_base units.
599 * @return the timestamp or AV_NOPTS_VALUE if an error occurred
600 */
601 int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index,
602 int64_t *pos, int64_t pos_limit);
603
604 /**
605 * Start/resume playing - only meaningful if using a network-based format
606 * (RTSP).
607 */
608 int (*read_play)(struct AVFormatContext *);
609
610 /**
611 * Pause playing - only meaningful if using a network-based format
612 * (RTSP).
613 */
614 int (*read_pause)(struct AVFormatContext *);
615
616 /**
617 * Seek to timestamp ts.
618 * Seeking will be done so that the point from which all active streams
619 * can be presented successfully will be closest to ts and within min/max_ts.
620 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
621 */
622 int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
623 } AVInputFormat;
624 /**
625 * @}
626 */
627
628 enum AVStreamParseType {
629 AVSTREAM_PARSE_NONE,
630 AVSTREAM_PARSE_FULL, /**< full parsing and repack */
631 AVSTREAM_PARSE_HEADERS, /**< Only parse headers, do not repack. */
632 AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */
633 AVSTREAM_PARSE_FULL_ONCE, /**< full parsing and repack of the first frame only, only implemented for H.264 currently */
634 };
635
636 typedef struct AVIndexEntry {
637 int64_t pos;
638 int64_t timestamp;
639 #define AVINDEX_KEYFRAME 0x0001
640 int flags:2;
641 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).
642 int min_distance; /**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */
643 } AVIndexEntry;
644
645 #define AV_DISPOSITION_DEFAULT 0x0001
646 #define AV_DISPOSITION_DUB 0x0002
647 #define AV_DISPOSITION_ORIGINAL 0x0004
648 #define AV_DISPOSITION_COMMENT 0x0008
649 #define AV_DISPOSITION_LYRICS 0x0010
650 #define AV_DISPOSITION_KARAOKE 0x0020
651
652 /**
653 * Track should be used during playback by default.
654 * Useful for subtitle track that should be displayed
655 * even when user did not explicitly ask for subtitles.
656 */
657 #define AV_DISPOSITION_FORCED 0x0040
658 #define AV_DISPOSITION_HEARING_IMPAIRED 0x0080 /**< stream for hearing impaired audiences */
659 #define AV_DISPOSITION_VISUAL_IMPAIRED 0x0100 /**< stream for visual impaired audiences */
660 #define AV_DISPOSITION_CLEAN_EFFECTS 0x0200 /**< stream without voice */
661 /**
662 * The stream is stored in the file as an attached picture/"cover art" (e.g.
663 * APIC frame in ID3v2). The single packet associated with it will be returned
664 * among the first few packets read from the file unless seeking takes place.
665 * It can also be accessed at any time in AVStream.attached_pic.
666 */
667 #define AV_DISPOSITION_ATTACHED_PIC 0x0400
668
669 /**
670 * Stream structure.
671 * New fields can be added to the end with minor version bumps.
672 * Removal, reordering and changes to existing fields require a major
673 * version bump.
674 * sizeof(AVStream) must not be used outside libav*.
675 */
676 typedef struct AVStream {
677 int index; /**< stream index in AVFormatContext */
678 /**
679 * Format-specific stream ID.
680 * decoding: set by libavformat
681 * encoding: set by the user, replaced by libavformat if left unset
682 */
683 int id;
684 /**
685 * Codec context associated with this stream. Allocated and freed by
686 * libavformat.
687 *
688 * - decoding: The demuxer exports codec information stored in the headers
689 * here.
690 * - encoding: The user sets codec information, the muxer writes it to the
691 * output. Mandatory fields as specified in AVCodecContext
692 * documentation must be set even if this AVCodecContext is
693 * not actually used for encoding.
694 */
695 AVCodecContext *codec;
696 void *priv_data;
697
698 /**
699 * encoding: pts generation when outputting stream
700 */
701 struct AVFrac pts;
702
703 /**
704 * This is the fundamental unit of time (in seconds) in terms
705 * of which frame timestamps are represented.
706 *
707 * decoding: set by libavformat
708 * encoding: set by libavformat in avformat_write_header. The muxer may use the
709 * user-provided value of @ref AVCodecContext.time_base "codec->time_base"
710 * as a hint.
711 */
712 AVRational time_base;
713
714 /**
715 * Decoding: pts of the first frame of the stream, in stream time base.
716 * Only set this if you are absolutely 100% sure that the value you set
717 * it to really is the pts of the first frame.
718 * This may be undefined (AV_NOPTS_VALUE).
719 */
720 int64_t start_time;
721
722 /**
723 * Decoding: duration of the stream, in stream time base.
724 * If a source file does not specify a duration, but does specify
725 * a bitrate, this value will be estimated from bitrate and file size.
726 */
727 int64_t duration;
728
729 int64_t nb_frames; ///< number of frames in this stream if known or 0
730
731 int disposition; /**< AV_DISPOSITION_* bit field */
732
733 enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
734
735 /**
736 * sample aspect ratio (0 if unknown)
737 * - encoding: Set by user.
738 * - decoding: Set by libavformat.
739 */
740 AVRational sample_aspect_ratio;
741
742 AVDictionary *metadata;
743
744 /**
745 * Average framerate
746 */
747 AVRational avg_frame_rate;
748
749 /**
750 * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
751 * will contain the attached picture.
752 *
753 * decoding: set by libavformat, must not be modified by the caller.
754 * encoding: unused
755 */
756 AVPacket attached_pic;
757
758 /**
759 * An array of side data that applies to the whole stream (i.e. the
760 * container does not allow it to change between packets).
761 *
762 * There may be no overlap between the side data in this array and side data
763 * in the packets. I.e. a given side data is either exported by the muxer
764 * (demuxing) / set by the caller (muxing) in this array, then it never
765 * appears in the packets, or the side data is exported / sent through
766 * the packets (always in the first packet where the value becomes known or
767 * changes), then it does not appear in this array.
768 *
769 * - demuxing: Set by libavformat when the stream is created.
770 * - muxing: May be set by the caller before avformat_write_header().
771 *
772 * Freed by libavformat in avformat_free_context().
773 */
774 AVPacketSideData *side_data;
775 /**
776 * The number of elements in the AVStream.side_data array.
777 */
778 int nb_side_data;
779
780 /*****************************************************************
781 * All fields below this line are not part of the public API. They
782 * may not be used outside of libavformat and can be changed and
783 * removed at will.
784 * New public fields should be added right above.
785 *****************************************************************
786 */
787
788 /**
789 * Stream information used internally by av_find_stream_info()
790 */
791 #define MAX_STD_TIMEBASES (60*12+5)
792 struct {
793 int nb_decoded_frames;
794 int found_decoder;
795
796 /**
797 * Those are used for average framerate estimation.
798 */
799 int64_t fps_first_dts;
800 int fps_first_dts_idx;
801 int64_t fps_last_dts;
802 int fps_last_dts_idx;
803
804 } *info;
805
806 int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
807
808 #if FF_API_REFERENCE_DTS
809 /* a hack to keep ABI compatibility for avconv, which accesses parser even
810 * though it should not */
811 int64_t do_not_use;
812 #endif
813 // Timestamp generation support:
814 int64_t first_dts;
815 int64_t cur_dts;
816 int64_t last_IP_pts;
817 int last_IP_duration;
818
819 /**
820 * Number of packets to buffer for codec probing
821 */
822 #define MAX_PROBE_PACKETS 2500
823 int probe_packets;
824
825 /**
826 * Number of frames that have been demuxed during av_find_stream_info()
827 */
828 int codec_info_nb_frames;
829
830 /* av_read_frame() support */
831 enum AVStreamParseType need_parsing;
832 struct AVCodecParserContext *parser;
833
834 /**
835 * last packet in packet_buffer for this stream when muxing.
836 */
837 struct AVPacketList *last_in_packet_buffer;
838 AVProbeData probe_data;
839 #define MAX_REORDER_DELAY 16
840 int64_t pts_buffer[MAX_REORDER_DELAY+1];
841
842 AVIndexEntry *index_entries; /**< Only used if the format does not
843 support seeking natively. */
844 int nb_index_entries;
845 unsigned int index_entries_allocated_size;
846 } AVStream;
847
848 #define AV_PROGRAM_RUNNING 1
849
850 /**
851 * New fields can be added to the end with minor version bumps.
852 * Removal, reordering and changes to existing fields require a major
853 * version bump.
854 * sizeof(AVProgram) must not be used outside libav*.
855 */
856 typedef struct AVProgram {
857 int id;
858 int flags;
859 enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
860 unsigned int *stream_index;
861 unsigned int nb_stream_indexes;
862 AVDictionary *metadata;
863 } AVProgram;
864
865 #define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
866 (streams are added dynamically) */
867
868 typedef struct AVChapter {
869 int id; ///< unique ID to identify the chapter
870 AVRational time_base; ///< time base in which the start/end timestamps are specified
871 int64_t start, end; ///< chapter start/end time in time_base units
872 AVDictionary *metadata;
873 } AVChapter;
874
875 typedef struct AVFormatInternal AVFormatInternal;
876
877 /**
878 * Format I/O context.
879 * New fields can be added to the end with minor version bumps.
880 * Removal, reordering and changes to existing fields require a major
881 * version bump.
882 * sizeof(AVFormatContext) must not be used outside libav*, use
883 * avformat_alloc_context() to create an AVFormatContext.
884 */
885 typedef struct AVFormatContext {
886 /**
887 * A class for logging and @ref avoptions. Set by avformat_alloc_context().
888 * Exports (de)muxer private options if they exist.
889 */
890 const AVClass *av_class;
891
892 /**
893 * The input container format.
894 *
895 * Demuxing only, set by avformat_open_input().
896 */
897 struct AVInputFormat *iformat;
898
899 /**
900 * The output container format.
901 *
902 * Muxing only, must be set by the caller before avformat_write_header().
903 */
904 struct AVOutputFormat *oformat;
905
906 /**
907 * Format private data. This is an AVOptions-enabled struct
908 * if and only if iformat/oformat.priv_class is not NULL.
909 *
910 * - muxing: set by avformat_write_header()
911 * - demuxing: set by avformat_open_input()
912 */
913 void *priv_data;
914
915 /**
916 * I/O context.
917 *
918 * - demuxing: either set by the user before avformat_open_input() (then
919 * the user must close it manually) or set by avformat_open_input().
920 * - muxing: set by the user before avformat_write_header(). The caller must
921 * take care of closing / freeing the IO context.
922 *
923 * Do NOT set this field if AVFMT_NOFILE flag is set in
924 * iformat/oformat.flags. In such a case, the (de)muxer will handle
925 * I/O in some other way and this field will be NULL.
926 */
927 AVIOContext *pb;
928
929 /* stream info */
930 int ctx_flags; /**< Format-specific flags, see AVFMTCTX_xx */
931
932 /**
933 * Number of elements in AVFormatContext.streams.
934 *
935 * Set by avformat_new_stream(), must not be modified by any other code.
936 */
937 unsigned int nb_streams;
938 /**
939 * A list of all streams in the file. New streams are created with
940 * avformat_new_stream().
941 *
942 * - demuxing: streams are created by libavformat in avformat_open_input().
943 * If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
944 * appear in av_read_frame().
945 * - muxing: streams are created by the user before avformat_write_header().
946 *
947 * Freed by libavformat in avformat_free_context().
948 */
949 AVStream **streams;
950
951 /**
952 * input or output filename
953 *
954 * - demuxing: set by avformat_open_input()
955 * - muxing: may be set by the caller before avformat_write_header()
956 */
957 char filename[1024];
958
959 /**
960 * Position of the first frame of the component, in
961 * AV_TIME_BASE fractional seconds. NEVER set this value directly:
962 * It is deduced from the AVStream values.
963 *
964 * Demuxing only, set by libavformat.
965 */
966 int64_t start_time;
967
968 /**
969 * Duration of the stream, in AV_TIME_BASE fractional
970 * seconds. Only set this value if you know none of the individual stream
971 * durations and also do not set any of them. This is deduced from the
972 * AVStream values if not set.
973 *
974 * Demuxing only, set by libavformat.
975 */
976 int64_t duration;
977
978 /**
979 * Total stream bitrate in bit/s, 0 if not
980 * available. Never set it directly if the file_size and the
981 * duration are known as Libav can compute it automatically.
982 */
983 int bit_rate;
984
985 unsigned int packet_size;
986 int max_delay;
987
988 int flags;
989 #define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
990 #define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
991 #define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
992 #define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
993 #define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container
994 #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
995 #define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
996 #define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
997 #define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
998 #define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
999
1000 /**
1001 * Maximum size of the data read from input for determining
1002 * the input container format.
1003 * Demuxing only, set by the caller before avformat_open_input().
1004 */
1005 unsigned int probesize;
1006
1007 /**
1008 * Maximum duration (in AV_TIME_BASE units) of the data read
1009 * from input in avformat_find_stream_info().
1010 * Demuxing only, set by the caller before avformat_find_stream_info().
1011 */
1012 int max_analyze_duration;
1013
1014 const uint8_t *key;
1015 int keylen;
1016
1017 unsigned int nb_programs;
1018 AVProgram **programs;
1019
1020 /**
1021 * Forced video codec_id.
1022 * Demuxing: Set by user.
1023 */
1024 enum AVCodecID video_codec_id;
1025
1026 /**
1027 * Forced audio codec_id.
1028 * Demuxing: Set by user.
1029 */
1030 enum AVCodecID audio_codec_id;
1031
1032 /**
1033 * Forced subtitle codec_id.
1034 * Demuxing: Set by user.
1035 */
1036 enum AVCodecID subtitle_codec_id;
1037
1038 /**
1039 * Maximum amount of memory in bytes to use for the index of each stream.
1040 * If the index exceeds this size, entries will be discarded as
1041 * needed to maintain a smaller size. This can lead to slower or less
1042 * accurate seeking (depends on demuxer).
1043 * Demuxers for which a full in-memory index is mandatory will ignore
1044 * this.
1045 * - muxing: unused
1046 * - demuxing: set by user
1047 */
1048 unsigned int max_index_size;
1049
1050 /**
1051 * Maximum amount of memory in bytes to use for buffering frames
1052 * obtained from realtime capture devices.
1053 */
1054 unsigned int max_picture_buffer;
1055
1056 /**
1057 * Number of chapters in AVChapter array.
1058 * When muxing, chapters are normally written in the file header,
1059 * so nb_chapters should normally be initialized before write_header
1060 * is called. Some muxers (e.g. mov and mkv) can also write chapters
1061 * in the trailer. To write chapters in the trailer, nb_chapters
1062 * must be zero when write_header is called and non-zero when
1063 * write_trailer is called.
1064 * - muxing: set by user
1065 * - demuxing: set by libavformat
1066 */
1067 unsigned int nb_chapters;
1068 AVChapter **chapters;
1069
1070 /**
1071 * Metadata that applies to the whole file.
1072 *
1073 * - demuxing: set by libavformat in avformat_open_input()
1074 * - muxing: may be set by the caller before avformat_write_header()
1075 *
1076 * Freed by libavformat in avformat_free_context().
1077 */
1078 AVDictionary *metadata;
1079
1080 /**
1081 * Start time of the stream in real world time, in microseconds
1082 * since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1083 * stream was captured at this real world time.
1084 * Muxing only, set by the caller before avformat_write_header().
1085 */
1086 int64_t start_time_realtime;
1087
1088 /**
1089 * The number of frames used for determining the framerate in
1090 * avformat_find_stream_info().
1091 * Demuxing only, set by the caller before avformat_find_stream_info().
1092 */
1093 int fps_probe_size;
1094
1095 /**
1096 * Error recognition; higher values will detect more errors but may
1097 * misdetect some more or less valid parts as errors.
1098 * Demuxing only, set by the caller before avformat_open_input().
1099 */
1100 int error_recognition;
1101
1102 /**
1103 * Custom interrupt callbacks for the I/O layer.
1104 *
1105 * demuxing: set by the user before avformat_open_input().
1106 * muxing: set by the user before avformat_write_header()
1107 * (mainly useful for AVFMT_NOFILE formats). The callback
1108 * should also be passed to avio_open2() if it's used to
1109 * open the file.
1110 */
1111 AVIOInterruptCB interrupt_callback;
1112
1113 /**
1114 * Flags to enable debugging.
1115 */
1116 int debug;
1117 #define FF_FDEBUG_TS 0x0001
1118
1119 /**
1120 * Maximum buffering duration for interleaving.
1121 *
1122 * To ensure all the streams are interleaved correctly,
1123 * av_interleaved_write_frame() will wait until it has at least one packet
1124 * for each stream before actually writing any packets to the output file.
1125 * When some streams are "sparse" (i.e. there are large gaps between
1126 * successive packets), this can result in excessive buffering.
1127 *
1128 * This field specifies the maximum difference between the timestamps of the
1129 * first and the last packet in the muxing queue, above which libavformat
1130 * will output a packet regardless of whether it has queued a packet for all
1131 * the streams.
1132 *
1133 * Muxing only, set by the caller before avformat_write_header().
1134 */
1135 int64_t max_interleave_delta;
1136
1137 /*****************************************************************
1138 * All fields below this line are not part of the public API. They
1139 * may not be used outside of libavformat and can be changed and
1140 * removed at will.
1141 * New public fields should be added right above.
1142 *****************************************************************
1143 */
1144
1145 /**
1146 * This buffer is only needed when packets were already buffered but
1147 * not decoded, for example to get the codec parameters in MPEG
1148 * streams.
1149 */
1150 struct AVPacketList *packet_buffer;
1151 struct AVPacketList *packet_buffer_end;
1152
1153 /* av_seek_frame() support */
1154 int64_t data_offset; /**< offset of the first packet */
1155
1156 /**
1157 * Raw packets from the demuxer, prior to parsing and decoding.
1158 * This buffer is used for buffering packets until the codec can
1159 * be identified, as parsing cannot be done without knowing the
1160 * codec.
1161 */
1162 struct AVPacketList *raw_packet_buffer;
1163 struct AVPacketList *raw_packet_buffer_end;
1164 /**
1165 * Packets split by the parser get queued here.
1166 */
1167 struct AVPacketList *parse_queue;
1168 struct AVPacketList *parse_queue_end;
1169 /**
1170 * Remaining size available for raw_packet_buffer, in bytes.
1171 */
1172 #define RAW_PACKET_BUFFER_SIZE 2500000
1173 int raw_packet_buffer_remaining_size;
1174
1175 /**
1176 * Offset to remap timestamps to be non-negative.
1177 * Expressed in timebase units.
1178 */
1179 int64_t offset;
1180
1181 /**
1182 * Timebase for the timestamp offset.
1183 */
1184 AVRational offset_timebase;
1185
1186 /**
1187 * An opaque field for libavformat internal usage.
1188 * Must not be accessed in any way by callers.
1189 */
1190 AVFormatInternal *internal;
1191 } AVFormatContext;
1192
1193 typedef struct AVPacketList {
1194 AVPacket pkt;
1195 struct AVPacketList *next;
1196 } AVPacketList;
1197
1198
1199 /**
1200 * @defgroup lavf_core Core functions
1201 * @ingroup libavf
1202 *
1203 * Functions for querying libavformat capabilities, allocating core structures,
1204 * etc.
1205 * @{
1206 */
1207
1208 /**
1209 * Return the LIBAVFORMAT_VERSION_INT constant.
1210 */
1211 unsigned avformat_version(void);
1212
1213 /**
1214 * Return the libavformat build-time configuration.
1215 */
1216 const char *avformat_configuration(void);
1217
1218 /**
1219 * Return the libavformat license.
1220 */
1221 const char *avformat_license(void);
1222
1223 /**
1224 * Initialize libavformat and register all the muxers, demuxers and
1225 * protocols. If you do not call this function, then you can select
1226 * exactly which formats you want to support.
1227 *
1228 * @see av_register_input_format()
1229 * @see av_register_output_format()
1230 * @see av_register_protocol()
1231 */
1232 void av_register_all(void);
1233
1234 void av_register_input_format(AVInputFormat *format);
1235 void av_register_output_format(AVOutputFormat *format);
1236
1237 /**
1238 * Do global initialization of network components. This is optional,
1239 * but recommended, since it avoids the overhead of implicitly
1240 * doing the setup for each session.
1241 *
1242 * Calling this function will become mandatory if using network
1243 * protocols at some major version bump.
1244 */
1245 int avformat_network_init(void);
1246
1247 /**
1248 * Undo the initialization done by avformat_network_init.
1249 */
1250 int avformat_network_deinit(void);
1251
1252 /**
1253 * If f is NULL, returns the first registered input format,
1254 * if f is non-NULL, returns the next registered input format after f
1255 * or NULL if f is the last one.
1256 */
1257 AVInputFormat *av_iformat_next(AVInputFormat *f);
1258
1259 /**
1260 * If f is NULL, returns the first registered output format,
1261 * if f is non-NULL, returns the next registered output format after f
1262 * or NULL if f is the last one.
1263 */
1264 AVOutputFormat *av_oformat_next(AVOutputFormat *f);
1265
1266 /**
1267 * Allocate an AVFormatContext.
1268 * avformat_free_context() can be used to free the context and everything
1269 * allocated by the framework within it.
1270 */
1271 AVFormatContext *avformat_alloc_context(void);
1272
1273 /**
1274 * Free an AVFormatContext and all its streams.
1275 * @param s context to free
1276 */
1277 void avformat_free_context(AVFormatContext *s);
1278
1279 /**
1280 * Get the AVClass for AVFormatContext. It can be used in combination with
1281 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
1282 *
1283 * @see av_opt_find().
1284 */
1285 const AVClass *avformat_get_class(void);
1286
1287 /**
1288 * Add a new stream to a media file.
1289 *
1290 * When demuxing, it is called by the demuxer in read_header(). If the
1291 * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
1292 * be called in read_packet().
1293 *
1294 * When muxing, should be called by the user before avformat_write_header().
1295 *
1296 * @param s media file handle
1297 * @param c If non-NULL, the AVCodecContext corresponding to the new stream
1298 * will be initialized to use this codec. This is needed for e.g. codec-specific
1299 * defaults to be set, so codec should be provided if it is known.
1300 *
1301 * @return newly created stream or NULL on error.
1302 */
1303 AVStream *avformat_new_stream(AVFormatContext *s, AVCodec *c);
1304
1305 AVProgram *av_new_program(AVFormatContext *s, int id);
1306
1307 /**
1308 * @}
1309 */
1310
1311
1312 /**
1313 * @addtogroup lavf_decoding
1314 * @{
1315 */
1316
1317 /**
1318 * Find AVInputFormat based on the short name of the input format.
1319 */
1320 AVInputFormat *av_find_input_format(const char *short_name);
1321
1322 /**
1323 * Guess the file format.
1324 *
1325 * @param pd data to be probed
1326 * @param is_opened Whether the file is already opened; determines whether
1327 * demuxers with or without AVFMT_NOFILE are probed.
1328 */
1329 AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened);
1330
1331 /**
1332 * Guess the file format.
1333 *
1334 * @param pd data to be probed
1335 * @param is_opened Whether the file is already opened; determines whether
1336 * demuxers with or without AVFMT_NOFILE are probed.
1337 * @param score_max A probe score larger that this is required to accept a
1338 * detection, the variable is set to the actual detection
1339 * score afterwards.
1340 * If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
1341 * to retry with a larger probe buffer.
1342 */
1343 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max);
1344
1345 /**
1346 * Probe a bytestream to determine the input format. Each time a probe returns
1347 * with a score that is too low, the probe buffer size is increased and another
1348 * attempt is made. When the maximum probe size is reached, the input format
1349 * with the highest score is returned.
1350 *
1351 * @param pb the bytestream to probe
1352 * @param fmt the input format is put here
1353 * @param filename the filename of the stream
1354 * @param logctx the log context
1355 * @param offset the offset within the bytestream to probe from
1356 * @param max_probe_size the maximum probe buffer size (zero for default)
1357 * @return 0 in case of success, a negative value corresponding to an
1358 * AVERROR code otherwise
1359 */
1360 int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
1361 const char *filename, void *logctx,
1362 unsigned int offset, unsigned int max_probe_size);
1363
1364 /**
1365 * Open an input stream and read the header. The codecs are not opened.
1366 * The stream must be closed with avformat_close_input().
1367 *
1368 * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
1369 * May be a pointer to NULL, in which case an AVFormatContext is allocated by this
1370 * function and written into ps.
1371 * Note that a user-supplied AVFormatContext will be freed on failure.
1372 * @param filename Name of the stream to open.
1373 * @param fmt If non-NULL, this parameter forces a specific input format.
1374 * Otherwise the format is autodetected.
1375 * @param options A dictionary filled with AVFormatContext and demuxer-private options.
1376 * On return this parameter will be destroyed and replaced with a dict containing
1377 * options that were not found. May be NULL.
1378 *
1379 * @return 0 on success, a negative AVERROR on failure.
1380 *
1381 * @note If you want to use custom IO, preallocate the format context and set its pb field.
1382 */
1383 int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options);
1384
1385 /**
1386 * Read packets of a media file to get stream information. This
1387 * is useful for file formats with no headers such as MPEG. This
1388 * function also computes the real framerate in case of MPEG-2 repeat
1389 * frame mode.
1390 * The logical file position is not changed by this function;
1391 * examined packets may be buffered for later processing.
1392 *
1393 * @param ic media file handle
1394 * @param options If non-NULL, an ic.nb_streams long array of pointers to
1395 * dictionaries, where i-th member contains options for
1396 * codec corresponding to i-th stream.
1397 * On return each dictionary will be filled with options that were not found.
1398 * @return >=0 if OK, AVERROR_xxx on error
1399 *
1400 * @note this function isn't guaranteed to open all the codecs, so
1401 * options being non-empty at return is a perfectly normal behavior.
1402 *
1403 * @todo Let the user decide somehow what information is needed so that
1404 * we do not waste time getting stuff the user does not need.
1405 */
1406 int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options);
1407
1408 /**
1409 * Find the "best" stream in the file.
1410 * The best stream is determined according to various heuristics as the most
1411 * likely to be what the user expects.
1412 * If the decoder parameter is non-NULL, av_find_best_stream will find the
1413 * default decoder for the stream's codec; streams for which no decoder can
1414 * be found are ignored.
1415 *
1416 * @param ic media file handle
1417 * @param type stream type: video, audio, subtitles, etc.
1418 * @param wanted_stream_nb user-requested stream number,
1419 * or -1 for automatic selection
1420 * @param related_stream try to find a stream related (eg. in the same
1421 * program) to this one, or -1 if none
1422 * @param decoder_ret if non-NULL, returns the decoder for the
1423 * selected stream
1424 * @param flags flags; none are currently defined
1425 * @return the non-negative stream number in case of success,
1426 * AVERROR_STREAM_NOT_FOUND if no stream with the requested type
1427 * could be found,
1428 * AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
1429 * @note If av_find_best_stream returns successfully and decoder_ret is not
1430 * NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
1431 */
1432 int av_find_best_stream(AVFormatContext *ic,
1433 enum AVMediaType type,
1434 int wanted_stream_nb,
1435 int related_stream,
1436 AVCodec **decoder_ret,
1437 int flags);
1438
1439 /**
1440 * Return the next frame of a stream.
1441 * This function returns what is stored in the file, and does not validate
1442 * that what is there are valid frames for the decoder. It will split what is
1443 * stored in the file into frames and return one for each call. It will not
1444 * omit invalid data between valid frames so as to give the decoder the maximum
1445 * information possible for decoding.
1446 *
1447 * If pkt->buf is NULL, then the packet is valid until the next
1448 * av_read_frame() or until avformat_close_input(). Otherwise the packet
1449 * is valid indefinitely. In both cases the packet must be freed with
1450 * av_free_packet when it is no longer needed. For video, the packet contains
1451 * exactly one frame. For audio, it contains an integer number of frames if each
1452 * frame has a known fixed size (e.g. PCM or ADPCM data). If the audio frames
1453 * have a variable size (e.g. MPEG audio), then it contains one frame.
1454 *
1455 * pkt->pts, pkt->dts and pkt->duration are always set to correct
1456 * values in AVStream.time_base units (and guessed if the format cannot
1457 * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
1458 * has B-frames, so it is better to rely on pkt->dts if you do not
1459 * decompress the payload.
1460 *
1461 * @return 0 if OK, < 0 on error or end of file
1462 */
1463 int av_read_frame(AVFormatContext *s, AVPacket *pkt);
1464
1465 /**
1466 * Seek to the keyframe at timestamp.
1467 * 'timestamp' in 'stream_index'.
1468 *
1469 * @param s media file handle
1470 * @param stream_index If stream_index is (-1), a default
1471 * stream is selected, and timestamp is automatically converted
1472 * from AV_TIME_BASE units to the stream specific time_base.
1473 * @param timestamp Timestamp in AVStream.time_base units
1474 * or, if no stream is specified, in AV_TIME_BASE units.
1475 * @param flags flags which select direction and seeking mode
1476 * @return >= 0 on success
1477 */
1478 int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
1479 int flags);
1480
1481 /**
1482 * Seek to timestamp ts.
1483 * Seeking will be done so that the point from which all active streams
1484 * can be presented successfully will be closest to ts and within min/max_ts.
1485 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
1486 *
1487 * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
1488 * are the file position (this may not be supported by all demuxers).
1489 * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
1490 * in the stream with stream_index (this may not be supported by all demuxers).
1491 * Otherwise all timestamps are in units of the stream selected by stream_index
1492 * or if stream_index is -1, in AV_TIME_BASE units.
1493 * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
1494 * keyframes (this may not be supported by all demuxers).
1495 *
1496 * @param s media file handle
1497 * @param stream_index index of the stream which is used as time base reference
1498 * @param min_ts smallest acceptable timestamp
1499 * @param ts target timestamp
1500 * @param max_ts largest acceptable timestamp
1501 * @param flags flags
1502 * @return >=0 on success, error code otherwise
1503 *
1504 * @note This is part of the new seek API which is still under construction.
1505 * Thus do not use this yet. It may change at any time, do not expect
1506 * ABI compatibility yet!
1507 */
1508 int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
1509
1510 /**
1511 * Start playing a network-based stream (e.g. RTSP stream) at the
1512 * current position.
1513 */
1514 int av_read_play(AVFormatContext *s);
1515
1516 /**
1517 * Pause a network-based stream (e.g. RTSP stream).
1518 *
1519 * Use av_read_play() to resume it.
1520 */
1521 int av_read_pause(AVFormatContext *s);
1522
1523 /**
1524 * Close an opened input AVFormatContext. Free it and all its contents
1525 * and set *s to NULL.
1526 */
1527 void avformat_close_input(AVFormatContext **s);
1528 /**
1529 * @}
1530 */
1531
1532 #define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
1533 #define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
1534 #define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
1535 #define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
1536
1537 /**
1538 * @addtogroup lavf_encoding
1539 * @{
1540 */
1541 /**
1542 * Allocate the stream private data and write the stream header to
1543 * an output media file.
1544 *
1545 * @param s Media file handle, must be allocated with avformat_alloc_context().
1546 * Its oformat field must be set to the desired output format;
1547 * Its pb field must be set to an already opened AVIOContext.
1548 * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
1549 * On return this parameter will be destroyed and replaced with a dict containing
1550 * options that were not found. May be NULL.
1551 *
1552 * @return 0 on success, negative AVERROR on failure.
1553 *
1554 * @see av_opt_find, av_dict_set, avio_open, av_oformat_next.
1555 */
1556 int avformat_write_header(AVFormatContext *s, AVDictionary **options);
1557
1558 /**
1559 * Write a packet to an output media file.
1560 *
1561 * This function passes the packet directly to the muxer, without any buffering
1562 * or reordering. The caller is responsible for correctly interleaving the
1563 * packets if the format requires it. Callers that want libavformat to handle
1564 * the interleaving should call av_interleaved_write_frame() instead of this
1565 * function.
1566 *
1567 * @param s media file handle
1568 * @param pkt The packet containing the data to be written. Note that unlike
1569 * av_interleaved_write_frame(), this function does not take
1570 * ownership of the packet passed to it (though some muxers may make
1571 * an internal reference to the input packet).
1572 * <br>
1573 * This parameter can be NULL (at any time, not just at the end), in
1574 * order to immediately flush data buffered within the muxer, for
1575 * muxers that buffer up data internally before writing it to the
1576 * output.
1577 * <br>
1578 * Packet's @ref AVPacket.stream_index "stream_index" field must be
1579 * set to the index of the corresponding stream in @ref
1580 * AVFormatContext.streams "s->streams". It is very strongly
1581 * recommended that timing information (@ref AVPacket.pts "pts", @ref
1582 * AVPacket.dts "dts", @ref AVPacket.duration "duration") is set to
1583 * correct values.
1584 * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
1585 *
1586 * @see av_interleaved_write_frame()
1587 */
1588 int av_write_frame(AVFormatContext *s, AVPacket *pkt);
1589
1590 /**
1591 * Write a packet to an output media file ensuring correct interleaving.
1592 *
1593 * This function will buffer the packets internally as needed to make sure the
1594 * packets in the output file are properly interleaved in the order of
1595 * increasing dts. Callers doing their own interleaving should call
1596 * av_write_frame() instead of this function.
1597 *
1598 * @param s media file handle
1599 * @param pkt The packet containing the data to be written.
1600 * <br>
1601 * If the packet is reference-counted, this function will take
1602 * ownership of this reference and unreference it later when it sees
1603 * fit.
1604 * The caller must not access the data through this reference after
1605 * this function returns. If the packet is not reference-counted,
1606 * libavformat will make a copy.
1607 * <br>
1608 * This parameter can be NULL (at any time, not just at the end), to
1609 * flush the interleaving queues.
1610 * <br>
1611 * Packet's @ref AVPacket.stream_index "stream_index" field must be
1612 * set to the index of the corresponding stream in @ref
1613 * AVFormatContext.streams "s->streams". It is very strongly
1614 * recommended that timing information (@ref AVPacket.pts "pts", @ref
1615 * AVPacket.dts "dts", @ref AVPacket.duration "duration") is set to
1616 * correct values.
1617 *
1618 * @return 0 on success, a negative AVERROR on error. Libavformat will always
1619 * take care of freeing the packet, even if this function fails.
1620 *
1621 * @see av_write_frame(), AVFormatContext.max_interleave_delta
1622 */
1623 int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
1624
1625 /**
1626 * Write the stream trailer to an output media file and free the
1627 * file private data.
1628 *
1629 * May only be called after a successful call to avformat_write_header.
1630 *
1631 * @param s media file handle
1632 * @return 0 if OK, AVERROR_xxx on error
1633 */
1634 int av_write_trailer(AVFormatContext *s);
1635
1636 /**
1637 * Return the output format in the list of registered output formats
1638 * which best matches the provided parameters, or return NULL if
1639 * there is no match.
1640 *
1641 * @param short_name if non-NULL checks if short_name matches with the
1642 * names of the registered formats
1643 * @param filename if non-NULL checks if filename terminates with the
1644 * extensions of the registered formats
1645 * @param mime_type if non-NULL checks if mime_type matches with the
1646 * MIME type of the registered formats
1647 */
1648 AVOutputFormat *av_guess_format(const char *short_name,
1649 const char *filename,
1650 const char *mime_type);
1651
1652 /**
1653 * Guess the codec ID based upon muxer and filename.
1654 */
1655 enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
1656 const char *filename, const char *mime_type,
1657 enum AVMediaType type);
1658
1659 /**
1660 * @}
1661 */
1662
1663
1664 /**
1665 * @defgroup lavf_misc Utility functions
1666 * @ingroup libavf
1667 * @{
1668 *
1669 * Miscellaneous utility functions related to both muxing and demuxing
1670 * (or neither).
1671 */
1672
1673 /**
1674 * Send a nice hexadecimal dump of a buffer to the specified file stream.
1675 *
1676 * @param f The file stream pointer where the dump should be sent to.
1677 * @param buf buffer
1678 * @param size buffer size
1679 *
1680 * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
1681 */
1682 void av_hex_dump(FILE *f, const uint8_t *buf, int size);
1683
1684 /**
1685 * Send a nice hexadecimal dump of a buffer to the log.
1686 *
1687 * @param avcl A pointer to an arbitrary struct of which the first field is a
1688 * pointer to an AVClass struct.
1689 * @param level The importance level of the message, lower values signifying
1690 * higher importance.
1691 * @param buf buffer
1692 * @param size buffer size
1693 *
1694 * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
1695 */
1696 void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
1697
1698 /**
1699 * Send a nice dump of a packet to the specified file stream.
1700 *
1701 * @param f The file stream pointer where the dump should be sent to.
1702 * @param pkt packet to dump
1703 * @param dump_payload True if the payload must be displayed, too.
1704 * @param st AVStream that the packet belongs to
1705 */
1706 void av_pkt_dump2(FILE *f, AVPacket *pkt, int dump_payload, AVStream *st);
1707
1708
1709 /**
1710 * Send a nice dump of a packet to the log.
1711 *
1712 * @param avcl A pointer to an arbitrary struct of which the first field is a
1713 * pointer to an AVClass struct.
1714 * @param level The importance level of the message, lower values signifying
1715 * higher importance.
1716 * @param pkt packet to dump
1717 * @param dump_payload True if the payload must be displayed, too.
1718 * @param st AVStream that the packet belongs to
1719 */
1720 void av_pkt_dump_log2(void *avcl, int level, AVPacket *pkt, int dump_payload,
1721 AVStream *st);
1722
1723 /**
1724 * Get the AVCodecID for the given codec tag tag.
1725 * If no codec id is found returns AV_CODEC_ID_NONE.
1726 *
1727 * @param tags list of supported codec_id-codec_tag pairs, as stored
1728 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
1729 * @param tag codec tag to match to a codec ID
1730 */
1731 enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
1732
1733 /**
1734 * Get the codec tag for the given codec id id.
1735 * If no codec tag is found returns 0.
1736 *
1737 * @param tags list of supported codec_id-codec_tag pairs, as stored
1738 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
1739 * @param id codec ID to match to a codec tag
1740 */
1741 unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id);
1742
1743 int av_find_default_stream_index(AVFormatContext *s);
1744
1745 /**
1746 * Get the index for a specific timestamp.
1747 *
1748 * @param st stream that the timestamp belongs to
1749 * @param timestamp timestamp to retrieve the index for
1750 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
1751 * to the timestamp which is <= the requested one, if backward
1752 * is 0, then it will be >=
1753 * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
1754 * @return < 0 if no such timestamp could be found
1755 */
1756 int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
1757
1758 /**
1759 * Add an index entry into a sorted list. Update the entry if the list
1760 * already contains it.
1761 *
1762 * @param timestamp timestamp in the time base of the given stream
1763 */
1764 int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
1765 int size, int distance, int flags);
1766
1767
1768 /**
1769 * Split a URL string into components.
1770 *
1771 * The pointers to buffers for storing individual components may be null,
1772 * in order to ignore that component. Buffers for components not found are
1773 * set to empty strings. If the port is not found, it is set to a negative
1774 * value.
1775 *
1776 * @param proto the buffer for the protocol
1777 * @param proto_size the size of the proto buffer
1778 * @param authorization the buffer for the authorization
1779 * @param authorization_size the size of the authorization buffer
1780 * @param hostname the buffer for the host name
1781 * @param hostname_size the size of the hostname buffer
1782 * @param port_ptr a pointer to store the port number in
1783 * @param path the buffer for the path
1784 * @param path_size the size of the path buffer
1785 * @param url the URL to split
1786 */
1787 void av_url_split(char *proto, int proto_size,
1788 char *authorization, int authorization_size,
1789 char *hostname, int hostname_size,
1790 int *port_ptr,
1791 char *path, int path_size,
1792 const char *url);
1793
1794
1795 void av_dump_format(AVFormatContext *ic,
1796 int index,
1797 const char *url,
1798 int is_output);
1799
1800 /**
1801 * Return in 'buf' the path with '%d' replaced by a number.
1802 *
1803 * Also handles the '%0nd' format where 'n' is the total number
1804 * of digits and '%%'.
1805 *
1806 * @param buf destination buffer
1807 * @param buf_size destination buffer size
1808 * @param path numbered sequence string
1809 * @param number frame number
1810 * @return 0 if OK, -1 on format error
1811 */
1812 int av_get_frame_filename(char *buf, int buf_size,
1813 const char *path, int number);
1814
1815 /**
1816 * Check whether filename actually is a numbered sequence generator.
1817 *
1818 * @param filename possible numbered sequence string
1819 * @return 1 if a valid numbered sequence string, 0 otherwise
1820 */
1821 int av_filename_number_test(const char *filename);
1822
1823 /**
1824 * Generate an SDP for an RTP session.
1825 *
1826 * Note, this overwrites the id values of AVStreams in the muxer contexts
1827 * for getting unique dynamic payload types.
1828 *
1829 * @param ac array of AVFormatContexts describing the RTP streams. If the
1830 * array is composed by only one context, such context can contain
1831 * multiple AVStreams (one AVStream per RTP stream). Otherwise,
1832 * all the contexts in the array (an AVCodecContext per RTP stream)
1833 * must contain only one AVStream.
1834 * @param n_files number of AVCodecContexts contained in ac
1835 * @param buf buffer where the SDP will be stored (must be allocated by
1836 * the caller)
1837 * @param size the size of the buffer
1838 * @return 0 if OK, AVERROR_xxx on error
1839 */
1840 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
1841
1842 /**
1843 * Return a positive value if the given filename has one of the given
1844 * extensions, 0 otherwise.
1845 *
1846 * @param filename file name to check against the given extensions
1847 * @param extensions a comma-separated list of filename extensions
1848 */
1849 int av_match_ext(const char *filename, const char *extensions);
1850
1851 /**
1852 * Test if the given container can store a codec.
1853 *
1854 * @param ofmt container to check for compatibility
1855 * @param codec_id codec to potentially store in container
1856 * @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
1857 *
1858 * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
1859 * A negative number if this information is not available.
1860 */
1861 int avformat_query_codec(AVOutputFormat *ofmt, enum AVCodecID codec_id, int std_compliance);
1862
1863 /**
1864 * @defgroup riff_fourcc RIFF FourCCs
1865 * @{
1866 * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
1867 * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
1868 * following code:
1869 * @code
1870 * uint32_t tag = MKTAG('H', '2', '6', '4');
1871 * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
1872 * enum AVCodecID id = av_codec_get_id(table, tag);
1873 * @endcode
1874 */
1875 /**
1876 * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
1877 */
1878 const struct AVCodecTag *avformat_get_riff_video_tags(void);
1879 /**
1880 * @return the table mapping RIFF FourCCs for audio to AVCodecID.
1881 */
1882 const struct AVCodecTag *avformat_get_riff_audio_tags(void);
1883 /**
1884 * @}
1885 */
1886
1887 /**
1888 * @}
1889 */
1890
1891 #endif /* AVFORMAT_AVFORMAT_H */