4084b39f86068621a97a12f1aa859e965fd0227f
[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 pkt packet
346 * @param size desired payload size
347 * @return >0 (read size) if OK, AVERROR_xxx otherwise
348 */
349 int av_get_packet(AVIOContext *s, AVPacket *pkt, int size);
350
351
352 /**
353 * Read data and append it to the current content of the AVPacket.
354 * If pkt->size is 0 this is identical to av_get_packet.
355 * Note that this uses av_grow_packet and thus involves a realloc
356 * which is inefficient. Thus this function should only be used
357 * when there is no reasonable way to know (an upper bound of)
358 * the final size.
359 *
360 * @param pkt packet
361 * @param size amount of data to read
362 * @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
363 * will not be lost even if an error occurs.
364 */
365 int av_append_packet(AVIOContext *s, AVPacket *pkt, int size);
366
367 /*************************************************/
368 /* fractional numbers for exact pts handling */
369
370 /**
371 * The exact value of the fractional number is: 'val + num / den'.
372 * num is assumed to be 0 <= num < den.
373 */
374 typedef struct AVFrac {
375 int64_t val, num, den;
376 } AVFrac;
377
378 /*************************************************/
379 /* input/output formats */
380
381 struct AVCodecTag;
382
383 /**
384 * This structure contains the data a format has to probe a file.
385 */
386 typedef struct AVProbeData {
387 const char *filename;
388 unsigned char *buf; /**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */
389 int buf_size; /**< Size of buf except extra allocated bytes */
390 } AVProbeData;
391
392 #define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
393 #define AVPROBE_SCORE_MAX 100 ///< maximum score
394
395 #define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
396
397 /// Demuxer will use avio_open, no opened file should be provided by the caller.
398 #define AVFMT_NOFILE 0x0001
399 #define AVFMT_NEEDNUMBER 0x0002 /**< Needs '%d' in filename. */
400 #define AVFMT_SHOW_IDS 0x0008 /**< Show format stream IDs numbers. */
401 #define AVFMT_RAWPICTURE 0x0020 /**< Format wants AVPicture structure for
402 raw picture data. */
403 #define AVFMT_GLOBALHEADER 0x0040 /**< Format wants global header. */
404 #define AVFMT_NOTIMESTAMPS 0x0080 /**< Format does not need / have any timestamps. */
405 #define AVFMT_GENERIC_INDEX 0x0100 /**< Use generic index building code. */
406 #define AVFMT_TS_DISCONT 0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
407 #define AVFMT_VARIABLE_FPS 0x0400 /**< Format allows variable fps. */
408 #define AVFMT_NODIMENSIONS 0x0800 /**< Format does not need width/height */
409 #define AVFMT_NOSTREAMS 0x1000 /**< Format does not require any streams */
410 #define AVFMT_NOBINSEARCH 0x2000 /**< Format does not allow to fall back on binary search via read_timestamp */
411 #define AVFMT_NOGENSEARCH 0x4000 /**< Format does not allow to fall back on generic search */
412 #define AVFMT_NO_BYTE_SEEK 0x8000 /**< Format does not allow seeking by bytes */
413 #define AVFMT_ALLOW_FLUSH 0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
414 #define AVFMT_TS_NONSTRICT 0x20000 /**< Format does not require strictly
415 increasing timestamps, but they must
416 still be monotonic */
417 #define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative
418 timestamps. If not set the timestamp
419 will be shifted in av_write_frame and
420 av_interleaved_write_frame so they
421 start from 0. */
422
423 /**
424 * @addtogroup lavf_encoding
425 * @{
426 */
427 typedef struct AVOutputFormat {
428 const char *name;
429 /**
430 * Descriptive name for the format, meant to be more human-readable
431 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
432 * to define it.
433 */
434 const char *long_name;
435 const char *mime_type;
436 const char *extensions; /**< comma-separated filename extensions */
437 /* output support */
438 enum AVCodecID audio_codec; /**< default audio codec */
439 enum AVCodecID video_codec; /**< default video codec */
440 enum AVCodecID subtitle_codec; /**< default subtitle codec */
441 /**
442 * can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_RAWPICTURE,
443 * AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
444 * AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
445 * AVFMT_TS_NONSTRICT
446 */
447 int flags;
448
449 /**
450 * List of supported codec_id-codec_tag pairs, ordered by "better
451 * choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
452 */
453 const struct AVCodecTag * const *codec_tag;
454
455
456 const AVClass *priv_class; ///< AVClass for the private context
457
458 /*****************************************************************
459 * No fields below this line are part of the public API. They
460 * may not be used outside of libavformat and can be changed and
461 * removed at will.
462 * New public fields should be added right above.
463 *****************************************************************
464 */
465 struct AVOutputFormat *next;
466 /**
467 * size of private data so that it can be allocated in the wrapper
468 */
469 int priv_data_size;
470
471 int (*write_header)(struct AVFormatContext *);
472 /**
473 * Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,
474 * pkt can be NULL in order to flush data buffered in the muxer.
475 * When flushing, return 0 if there still is more data to flush,
476 * or 1 if everything was flushed and there is no more buffered
477 * data.
478 */
479 int (*write_packet)(struct AVFormatContext *, AVPacket *pkt);
480 int (*write_trailer)(struct AVFormatContext *);
481 /**
482 * Currently only used to set pixel format if not YUV420P.
483 */
484 int (*interleave_packet)(struct AVFormatContext *, AVPacket *out,
485 AVPacket *in, int flush);
486 /**
487 * Test if the given codec can be stored in this container.
488 *
489 * @return 1 if the codec is supported, 0 if it is not.
490 * A negative number if unknown.
491 */
492 int (*query_codec)(enum AVCodecID id, int std_compliance);
493 } AVOutputFormat;
494 /**
495 * @}
496 */
497
498 /**
499 * @addtogroup lavf_decoding
500 * @{
501 */
502 typedef struct AVInputFormat {
503 /**
504 * A comma separated list of short names for the format. New names
505 * may be appended with a minor bump.
506 */
507 const char *name;
508
509 /**
510 * Descriptive name for the format, meant to be more human-readable
511 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
512 * to define it.
513 */
514 const char *long_name;
515
516 /**
517 * Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
518 * AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
519 * AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK.
520 */
521 int flags;
522
523 /**
524 * If extensions are defined, then no probe is done. You should
525 * usually not use extension format guessing because it is not
526 * reliable enough
527 */
528 const char *extensions;
529
530 const struct AVCodecTag * const *codec_tag;
531
532 const AVClass *priv_class; ///< AVClass for the private context
533
534 /*****************************************************************
535 * No fields below this line are part of the public API. They
536 * may not be used outside of libavformat and can be changed and
537 * removed at will.
538 * New public fields should be added right above.
539 *****************************************************************
540 */
541 struct AVInputFormat *next;
542
543 /**
544 * Raw demuxers store their codec ID here.
545 */
546 int raw_codec_id;
547
548 /**
549 * Size of private data so that it can be allocated in the wrapper.
550 */
551 int priv_data_size;
552
553 /**
554 * Tell if a given file has a chance of being parsed as this format.
555 * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
556 * big so you do not have to check for that unless you need more.
557 */
558 int (*read_probe)(AVProbeData *);
559
560 /**
561 * Read the format header and initialize the AVFormatContext
562 * structure. Return 0 if OK. Only used in raw format right
563 * now. 'avformat_new_stream' should be called to create new streams.
564 */
565 int (*read_header)(struct AVFormatContext *);
566
567 /**
568 * Read one packet and put it in 'pkt'. pts and flags are also
569 * set. 'avformat_new_stream' can be called only if the flag
570 * AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
571 * background thread).
572 * @return 0 on success, < 0 on error.
573 * When returning an error, pkt must not have been allocated
574 * or must be freed before returning
575 */
576 int (*read_packet)(struct AVFormatContext *, AVPacket *pkt);
577
578 /**
579 * Close the stream. The AVFormatContext and AVStreams are not
580 * freed by this function
581 */
582 int (*read_close)(struct AVFormatContext *);
583
584 /**
585 * Seek to a given timestamp relative to the frames in
586 * stream component stream_index.
587 * @param stream_index Must not be -1.
588 * @param flags Selects which direction should be preferred if no exact
589 * match is available.
590 * @return >= 0 on success (but not necessarily the new offset)
591 */
592 int (*read_seek)(struct AVFormatContext *,
593 int stream_index, int64_t timestamp, int flags);
594
595 /**
596 * Get the next timestamp in stream[stream_index].time_base units.
597 * @return the timestamp or AV_NOPTS_VALUE if an error occurred
598 */
599 int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index,
600 int64_t *pos, int64_t pos_limit);
601
602 /**
603 * Start/resume playing - only meaningful if using a network-based format
604 * (RTSP).
605 */
606 int (*read_play)(struct AVFormatContext *);
607
608 /**
609 * Pause playing - only meaningful if using a network-based format
610 * (RTSP).
611 */
612 int (*read_pause)(struct AVFormatContext *);
613
614 /**
615 * Seek to timestamp ts.
616 * Seeking will be done so that the point from which all active streams
617 * can be presented successfully will be closest to ts and within min/max_ts.
618 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
619 */
620 int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
621 } AVInputFormat;
622 /**
623 * @}
624 */
625
626 enum AVStreamParseType {
627 AVSTREAM_PARSE_NONE,
628 AVSTREAM_PARSE_FULL, /**< full parsing and repack */
629 AVSTREAM_PARSE_HEADERS, /**< Only parse headers, do not repack. */
630 AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */
631 AVSTREAM_PARSE_FULL_ONCE, /**< full parsing and repack of the first frame only, only implemented for H.264 currently */
632 };
633
634 typedef struct AVIndexEntry {
635 int64_t pos;
636 int64_t timestamp;
637 #define AVINDEX_KEYFRAME 0x0001
638 int flags:2;
639 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).
640 int min_distance; /**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */
641 } AVIndexEntry;
642
643 #define AV_DISPOSITION_DEFAULT 0x0001
644 #define AV_DISPOSITION_DUB 0x0002
645 #define AV_DISPOSITION_ORIGINAL 0x0004
646 #define AV_DISPOSITION_COMMENT 0x0008
647 #define AV_DISPOSITION_LYRICS 0x0010
648 #define AV_DISPOSITION_KARAOKE 0x0020
649
650 /**
651 * Track should be used during playback by default.
652 * Useful for subtitle track that should be displayed
653 * even when user did not explicitly ask for subtitles.
654 */
655 #define AV_DISPOSITION_FORCED 0x0040
656 #define AV_DISPOSITION_HEARING_IMPAIRED 0x0080 /**< stream for hearing impaired audiences */
657 #define AV_DISPOSITION_VISUAL_IMPAIRED 0x0100 /**< stream for visual impaired audiences */
658 #define AV_DISPOSITION_CLEAN_EFFECTS 0x0200 /**< stream without voice */
659 /**
660 * The stream is stored in the file as an attached picture/"cover art" (e.g.
661 * APIC frame in ID3v2). The single packet associated with it will be returned
662 * among the first few packets read from the file unless seeking takes place.
663 * It can also be accessed at any time in AVStream.attached_pic.
664 */
665 #define AV_DISPOSITION_ATTACHED_PIC 0x0400
666
667 /**
668 * Stream structure.
669 * New fields can be added to the end with minor version bumps.
670 * Removal, reordering and changes to existing fields require a major
671 * version bump.
672 * sizeof(AVStream) must not be used outside libav*.
673 */
674 typedef struct AVStream {
675 int index; /**< stream index in AVFormatContext */
676 /**
677 * Format-specific stream ID.
678 * decoding: set by libavformat
679 * encoding: set by the user, replaced by libavformat if left unset
680 */
681 int id;
682 /**
683 * Codec context associated with this stream. Allocated and freed by
684 * libavformat.
685 *
686 * - decoding: The demuxer exports codec information stored in the headers
687 * here.
688 * - encoding: The user sets codec information, the muxer writes it to the
689 * output. Mandatory fields as specified in AVCodecContext
690 * documentation must be set even if this AVCodecContext is
691 * not actually used for encoding.
692 */
693 AVCodecContext *codec;
694 void *priv_data;
695
696 /**
697 * encoding: pts generation when outputting stream
698 */
699 struct AVFrac pts;
700
701 /**
702 * This is the fundamental unit of time (in seconds) in terms
703 * of which frame timestamps are represented.
704 *
705 * decoding: set by libavformat
706 * encoding: set by libavformat in avformat_write_header. The muxer may use the
707 * user-provided value of @ref AVCodecContext.time_base "codec->time_base"
708 * as a hint.
709 */
710 AVRational time_base;
711
712 /**
713 * Decoding: pts of the first frame of the stream, in stream time base.
714 * Only set this if you are absolutely 100% sure that the value you set
715 * it to really is the pts of the first frame.
716 * This may be undefined (AV_NOPTS_VALUE).
717 */
718 int64_t start_time;
719
720 /**
721 * Decoding: duration of the stream, in stream time base.
722 * If a source file does not specify a duration, but does specify
723 * a bitrate, this value will be estimated from bitrate and file size.
724 */
725 int64_t duration;
726
727 int64_t nb_frames; ///< number of frames in this stream if known or 0
728
729 int disposition; /**< AV_DISPOSITION_* bit field */
730
731 enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
732
733 /**
734 * sample aspect ratio (0 if unknown)
735 * - encoding: Set by user.
736 * - decoding: Set by libavformat.
737 */
738 AVRational sample_aspect_ratio;
739
740 AVDictionary *metadata;
741
742 /**
743 * Average framerate
744 */
745 AVRational avg_frame_rate;
746
747 /**
748 * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
749 * will contain the attached picture.
750 *
751 * decoding: set by libavformat, must not be modified by the caller.
752 * encoding: unused
753 */
754 AVPacket attached_pic;
755
756 /*****************************************************************
757 * All fields below this line are not part of the public API. They
758 * may not be used outside of libavformat and can be changed and
759 * removed at will.
760 * New public fields should be added right above.
761 *****************************************************************
762 */
763
764 /**
765 * Stream information used internally by av_find_stream_info()
766 */
767 #define MAX_STD_TIMEBASES (60*12+5)
768 struct {
769 int nb_decoded_frames;
770 int found_decoder;
771
772 /**
773 * Those are used for average framerate estimation.
774 */
775 int64_t fps_first_dts;
776 int fps_first_dts_idx;
777 int64_t fps_last_dts;
778 int fps_last_dts_idx;
779
780 } *info;
781
782 int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
783
784 #if FF_API_REFERENCE_DTS
785 /* a hack to keep ABI compatibility for avconv, which accesses parser even
786 * though it should not */
787 int64_t do_not_use;
788 #endif
789 // Timestamp generation support:
790 int64_t first_dts;
791 int64_t cur_dts;
792 int64_t last_IP_pts;
793 int last_IP_duration;
794
795 /**
796 * Number of packets to buffer for codec probing
797 */
798 #define MAX_PROBE_PACKETS 2500
799 int probe_packets;
800
801 /**
802 * Number of frames that have been demuxed during av_find_stream_info()
803 */
804 int codec_info_nb_frames;
805
806 /* av_read_frame() support */
807 enum AVStreamParseType need_parsing;
808 struct AVCodecParserContext *parser;
809
810 /**
811 * last packet in packet_buffer for this stream when muxing.
812 */
813 struct AVPacketList *last_in_packet_buffer;
814 AVProbeData probe_data;
815 #define MAX_REORDER_DELAY 16
816 int64_t pts_buffer[MAX_REORDER_DELAY+1];
817
818 AVIndexEntry *index_entries; /**< Only used if the format does not
819 support seeking natively. */
820 int nb_index_entries;
821 unsigned int index_entries_allocated_size;
822 } AVStream;
823
824 #define AV_PROGRAM_RUNNING 1
825
826 /**
827 * New fields can be added to the end with minor version bumps.
828 * Removal, reordering and changes to existing fields require a major
829 * version bump.
830 * sizeof(AVProgram) must not be used outside libav*.
831 */
832 typedef struct AVProgram {
833 int id;
834 int flags;
835 enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
836 unsigned int *stream_index;
837 unsigned int nb_stream_indexes;
838 AVDictionary *metadata;
839 } AVProgram;
840
841 #define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
842 (streams are added dynamically) */
843
844 typedef struct AVChapter {
845 int id; ///< unique ID to identify the chapter
846 AVRational time_base; ///< time base in which the start/end timestamps are specified
847 int64_t start, end; ///< chapter start/end time in time_base units
848 AVDictionary *metadata;
849 } AVChapter;
850
851 typedef struct AVFormatInternal AVFormatInternal;
852
853 /**
854 * Format I/O context.
855 * New fields can be added to the end with minor version bumps.
856 * Removal, reordering and changes to existing fields require a major
857 * version bump.
858 * sizeof(AVFormatContext) must not be used outside libav*, use
859 * avformat_alloc_context() to create an AVFormatContext.
860 */
861 typedef struct AVFormatContext {
862 /**
863 * A class for logging and AVOptions. Set by avformat_alloc_context().
864 * Exports (de)muxer private options if they exist.
865 */
866 const AVClass *av_class;
867
868 /**
869 * Can only be iformat or oformat, not both at the same time.
870 *
871 * decoding: set by avformat_open_input().
872 * encoding: set by the user.
873 */
874 struct AVInputFormat *iformat;
875 struct AVOutputFormat *oformat;
876
877 /**
878 * Format private data. This is an AVOptions-enabled struct
879 * if and only if iformat/oformat.priv_class is not NULL.
880 */
881 void *priv_data;
882
883 /**
884 * I/O context.
885 *
886 * decoding: either set by the user before avformat_open_input() (then
887 * the user must close it manually) or set by avformat_open_input().
888 * encoding: set by the user.
889 *
890 * Do NOT set this field if AVFMT_NOFILE flag is set in
891 * iformat/oformat.flags. In such a case, the (de)muxer will handle
892 * I/O in some other way and this field will be NULL.
893 */
894 AVIOContext *pb;
895
896 /* stream info */
897 int ctx_flags; /**< Format-specific flags, see AVFMTCTX_xx */
898
899 /**
900 * A list of all streams in the file. New streams are created with
901 * avformat_new_stream().
902 *
903 * decoding: streams are created by libavformat in avformat_open_input().
904 * If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
905 * appear in av_read_frame().
906 * encoding: streams are created by the user before avformat_write_header().
907 */
908 unsigned int nb_streams;
909 AVStream **streams;
910
911 char filename[1024]; /**< input or output filename */
912
913 /**
914 * Decoding: position of the first frame of the component, in
915 * AV_TIME_BASE fractional seconds. NEVER set this value directly:
916 * It is deduced from the AVStream values.
917 */
918 int64_t start_time;
919
920 /**
921 * Decoding: duration of the stream, in AV_TIME_BASE fractional
922 * seconds. Only set this value if you know none of the individual stream
923 * durations and also do not set any of them. This is deduced from the
924 * AVStream values if not set.
925 */
926 int64_t duration;
927
928 /**
929 * Decoding: total stream bitrate in bit/s, 0 if not
930 * available. Never set it directly if the file_size and the
931 * duration are known as Libav can compute it automatically.
932 */
933 int bit_rate;
934
935 unsigned int packet_size;
936 int max_delay;
937
938 int flags;
939 #define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
940 #define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
941 #define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
942 #define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
943 #define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container
944 #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
945 #define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible
946 #define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
947 #define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
948 #define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet.
949
950 /**
951 * decoding: size of data to probe; encoding: unused.
952 */
953 unsigned int probesize;
954
955 /**
956 * decoding: maximum time (in AV_TIME_BASE units) during which the input should
957 * be analyzed in avformat_find_stream_info().
958 */
959 int max_analyze_duration;
960
961 const uint8_t *key;
962 int keylen;
963
964 unsigned int nb_programs;
965 AVProgram **programs;
966
967 /**
968 * Forced video codec_id.
969 * Demuxing: Set by user.
970 */
971 enum AVCodecID video_codec_id;
972
973 /**
974 * Forced audio codec_id.
975 * Demuxing: Set by user.
976 */
977 enum AVCodecID audio_codec_id;
978
979 /**
980 * Forced subtitle codec_id.
981 * Demuxing: Set by user.
982 */
983 enum AVCodecID subtitle_codec_id;
984
985 /**
986 * Maximum amount of memory in bytes to use for the index of each stream.
987 * If the index exceeds this size, entries will be discarded as
988 * needed to maintain a smaller size. This can lead to slower or less
989 * accurate seeking (depends on demuxer).
990 * Demuxers for which a full in-memory index is mandatory will ignore
991 * this.
992 * muxing : unused
993 * demuxing: set by user
994 */
995 unsigned int max_index_size;
996
997 /**
998 * Maximum amount of memory in bytes to use for buffering frames
999 * obtained from realtime capture devices.
1000 */
1001 unsigned int max_picture_buffer;
1002
1003 /**
1004 * Number of chapters in AVChapter array.
1005 * When muxing, chapters are normally written in the file header,
1006 * so nb_chapters should normally be initialized before write_header
1007 * is called. Some muxers (e.g. mov and mkv) can also write chapters
1008 * in the trailer. To write chapters in the trailer, nb_chapters
1009 * must be zero when write_header is called and non-zero when
1010 * write_trailer is called.
1011 * muxing : set by user
1012 * demuxing: set by libavformat
1013 */
1014 unsigned int nb_chapters;
1015 AVChapter **chapters;
1016
1017 AVDictionary *metadata;
1018
1019 /**
1020 * Start time of the stream in real world time, in microseconds
1021 * since the unix epoch (00:00 1st January 1970). That is, pts=0
1022 * in the stream was captured at this real world time.
1023 * - encoding: Set by user.
1024 * - decoding: Unused.
1025 */
1026 int64_t start_time_realtime;
1027
1028 /**
1029 * decoding: number of frames used to probe fps
1030 */
1031 int fps_probe_size;
1032
1033 /**
1034 * Error recognition; higher values will detect more errors but may
1035 * misdetect some more or less valid parts as errors.
1036 * - encoding: unused
1037 * - decoding: Set by user.
1038 */
1039 int error_recognition;
1040
1041 /**
1042 * Custom interrupt callbacks for the I/O layer.
1043 *
1044 * decoding: set by the user before avformat_open_input().
1045 * encoding: set by the user before avformat_write_header()
1046 * (mainly useful for AVFMT_NOFILE formats). The callback
1047 * should also be passed to avio_open2() if it's used to
1048 * open the file.
1049 */
1050 AVIOInterruptCB interrupt_callback;
1051
1052 /**
1053 * Flags to enable debugging.
1054 */
1055 int debug;
1056 #define FF_FDEBUG_TS 0x0001
1057
1058 /**
1059 * Maximum buffering duration for interleaving.
1060 *
1061 * To ensure all the streams are interleaved correctly,
1062 * av_interleaved_write_frame() will wait until it has at least one packet
1063 * for each stream before actually writing any packets to the output file.
1064 * When some streams are "sparse" (i.e. there are large gaps between
1065 * successive packets), this can result in excessive buffering.
1066 *
1067 * This field specifies the maximum difference between the timestamps of the
1068 * first and the last packet in the muxing queue, above which libavformat
1069 * will output a packet regardless of whether it has queued a packet for all
1070 * the streams.
1071 *
1072 * Muxing only, set by the caller before avformat_write_header().
1073 */
1074 int64_t max_interleave_delta;
1075
1076 /*****************************************************************
1077 * All fields below this line are not part of the public API. They
1078 * may not be used outside of libavformat and can be changed and
1079 * removed at will.
1080 * New public fields should be added right above.
1081 *****************************************************************
1082 */
1083
1084 /**
1085 * This buffer is only needed when packets were already buffered but
1086 * not decoded, for example to get the codec parameters in MPEG
1087 * streams.
1088 */
1089 struct AVPacketList *packet_buffer;
1090 struct AVPacketList *packet_buffer_end;
1091
1092 /* av_seek_frame() support */
1093 int64_t data_offset; /**< offset of the first packet */
1094
1095 /**
1096 * Raw packets from the demuxer, prior to parsing and decoding.
1097 * This buffer is used for buffering packets until the codec can
1098 * be identified, as parsing cannot be done without knowing the
1099 * codec.
1100 */
1101 struct AVPacketList *raw_packet_buffer;
1102 struct AVPacketList *raw_packet_buffer_end;
1103 /**
1104 * Packets split by the parser get queued here.
1105 */
1106 struct AVPacketList *parse_queue;
1107 struct AVPacketList *parse_queue_end;
1108 /**
1109 * Remaining size available for raw_packet_buffer, in bytes.
1110 */
1111 #define RAW_PACKET_BUFFER_SIZE 2500000
1112 int raw_packet_buffer_remaining_size;
1113
1114 /**
1115 * Offset to remap timestamps to be non-negative.
1116 * Expressed in timebase units.
1117 */
1118 int64_t offset;
1119
1120 /**
1121 * Timebase for the timestamp offset.
1122 */
1123 AVRational offset_timebase;
1124
1125 /**
1126 * An opaque field for libavformat internal usage.
1127 * Must not be accessed in any way by callers.
1128 */
1129 AVFormatInternal *internal;
1130 } AVFormatContext;
1131
1132 typedef struct AVPacketList {
1133 AVPacket pkt;
1134 struct AVPacketList *next;
1135 } AVPacketList;
1136
1137
1138 /**
1139 * @defgroup lavf_core Core functions
1140 * @ingroup libavf
1141 *
1142 * Functions for querying libavformat capabilities, allocating core structures,
1143 * etc.
1144 * @{
1145 */
1146
1147 /**
1148 * Return the LIBAVFORMAT_VERSION_INT constant.
1149 */
1150 unsigned avformat_version(void);
1151
1152 /**
1153 * Return the libavformat build-time configuration.
1154 */
1155 const char *avformat_configuration(void);
1156
1157 /**
1158 * Return the libavformat license.
1159 */
1160 const char *avformat_license(void);
1161
1162 /**
1163 * Initialize libavformat and register all the muxers, demuxers and
1164 * protocols. If you do not call this function, then you can select
1165 * exactly which formats you want to support.
1166 *
1167 * @see av_register_input_format()
1168 * @see av_register_output_format()
1169 * @see av_register_protocol()
1170 */
1171 void av_register_all(void);
1172
1173 void av_register_input_format(AVInputFormat *format);
1174 void av_register_output_format(AVOutputFormat *format);
1175
1176 /**
1177 * Do global initialization of network components. This is optional,
1178 * but recommended, since it avoids the overhead of implicitly
1179 * doing the setup for each session.
1180 *
1181 * Calling this function will become mandatory if using network
1182 * protocols at some major version bump.
1183 */
1184 int avformat_network_init(void);
1185
1186 /**
1187 * Undo the initialization done by avformat_network_init.
1188 */
1189 int avformat_network_deinit(void);
1190
1191 /**
1192 * If f is NULL, returns the first registered input format,
1193 * if f is non-NULL, returns the next registered input format after f
1194 * or NULL if f is the last one.
1195 */
1196 AVInputFormat *av_iformat_next(AVInputFormat *f);
1197
1198 /**
1199 * If f is NULL, returns the first registered output format,
1200 * if f is non-NULL, returns the next registered output format after f
1201 * or NULL if f is the last one.
1202 */
1203 AVOutputFormat *av_oformat_next(AVOutputFormat *f);
1204
1205 /**
1206 * Allocate an AVFormatContext.
1207 * avformat_free_context() can be used to free the context and everything
1208 * allocated by the framework within it.
1209 */
1210 AVFormatContext *avformat_alloc_context(void);
1211
1212 /**
1213 * Free an AVFormatContext and all its streams.
1214 * @param s context to free
1215 */
1216 void avformat_free_context(AVFormatContext *s);
1217
1218 /**
1219 * Get the AVClass for AVFormatContext. It can be used in combination with
1220 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
1221 *
1222 * @see av_opt_find().
1223 */
1224 const AVClass *avformat_get_class(void);
1225
1226 /**
1227 * Add a new stream to a media file.
1228 *
1229 * When demuxing, it is called by the demuxer in read_header(). If the
1230 * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
1231 * be called in read_packet().
1232 *
1233 * When muxing, should be called by the user before avformat_write_header().
1234 *
1235 * @param c If non-NULL, the AVCodecContext corresponding to the new stream
1236 * will be initialized to use this codec. This is needed for e.g. codec-specific
1237 * defaults to be set, so codec should be provided if it is known.
1238 *
1239 * @return newly created stream or NULL on error.
1240 */
1241 AVStream *avformat_new_stream(AVFormatContext *s, AVCodec *c);
1242
1243 AVProgram *av_new_program(AVFormatContext *s, int id);
1244
1245 /**
1246 * @}
1247 */
1248
1249
1250 /**
1251 * @addtogroup lavf_decoding
1252 * @{
1253 */
1254
1255 /**
1256 * Find AVInputFormat based on the short name of the input format.
1257 */
1258 AVInputFormat *av_find_input_format(const char *short_name);
1259
1260 /**
1261 * Guess the file format.
1262 *
1263 * @param is_opened Whether the file is already opened; determines whether
1264 * demuxers with or without AVFMT_NOFILE are probed.
1265 */
1266 AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened);
1267
1268 /**
1269 * Guess the file format.
1270 *
1271 * @param is_opened Whether the file is already opened; determines whether
1272 * demuxers with or without AVFMT_NOFILE are probed.
1273 * @param score_max A probe score larger that this is required to accept a
1274 * detection, the variable is set to the actual detection
1275 * score afterwards.
1276 * If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
1277 * to retry with a larger probe buffer.
1278 */
1279 AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max);
1280
1281 /**
1282 * Probe a bytestream to determine the input format. Each time a probe returns
1283 * with a score that is too low, the probe buffer size is increased and another
1284 * attempt is made. When the maximum probe size is reached, the input format
1285 * with the highest score is returned.
1286 *
1287 * @param pb the bytestream to probe
1288 * @param fmt the input format is put here
1289 * @param filename the filename of the stream
1290 * @param logctx the log context
1291 * @param offset the offset within the bytestream to probe from
1292 * @param max_probe_size the maximum probe buffer size (zero for default)
1293 * @return 0 in case of success, a negative value corresponding to an
1294 * AVERROR code otherwise
1295 */
1296 int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
1297 const char *filename, void *logctx,
1298 unsigned int offset, unsigned int max_probe_size);
1299
1300 /**
1301 * Open an input stream and read the header. The codecs are not opened.
1302 * The stream must be closed with avformat_close_input().
1303 *
1304 * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
1305 * May be a pointer to NULL, in which case an AVFormatContext is allocated by this
1306 * function and written into ps.
1307 * Note that a user-supplied AVFormatContext will be freed on failure.
1308 * @param filename Name of the stream to open.
1309 * @param fmt If non-NULL, this parameter forces a specific input format.
1310 * Otherwise the format is autodetected.
1311 * @param options A dictionary filled with AVFormatContext and demuxer-private options.
1312 * On return this parameter will be destroyed and replaced with a dict containing
1313 * options that were not found. May be NULL.
1314 *
1315 * @return 0 on success, a negative AVERROR on failure.
1316 *
1317 * @note If you want to use custom IO, preallocate the format context and set its pb field.
1318 */
1319 int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options);
1320
1321 /**
1322 * Read packets of a media file to get stream information. This
1323 * is useful for file formats with no headers such as MPEG. This
1324 * function also computes the real framerate in case of MPEG-2 repeat
1325 * frame mode.
1326 * The logical file position is not changed by this function;
1327 * examined packets may be buffered for later processing.
1328 *
1329 * @param ic media file handle
1330 * @param options If non-NULL, an ic.nb_streams long array of pointers to
1331 * dictionaries, where i-th member contains options for
1332 * codec corresponding to i-th stream.
1333 * On return each dictionary will be filled with options that were not found.
1334 * @return >=0 if OK, AVERROR_xxx on error
1335 *
1336 * @note this function isn't guaranteed to open all the codecs, so
1337 * options being non-empty at return is a perfectly normal behavior.
1338 *
1339 * @todo Let the user decide somehow what information is needed so that
1340 * we do not waste time getting stuff the user does not need.
1341 */
1342 int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options);
1343
1344 /**
1345 * Find the "best" stream in the file.
1346 * The best stream is determined according to various heuristics as the most
1347 * likely to be what the user expects.
1348 * If the decoder parameter is non-NULL, av_find_best_stream will find the
1349 * default decoder for the stream's codec; streams for which no decoder can
1350 * be found are ignored.
1351 *
1352 * @param ic media file handle
1353 * @param type stream type: video, audio, subtitles, etc.
1354 * @param wanted_stream_nb user-requested stream number,
1355 * or -1 for automatic selection
1356 * @param related_stream try to find a stream related (eg. in the same
1357 * program) to this one, or -1 if none
1358 * @param decoder_ret if non-NULL, returns the decoder for the
1359 * selected stream
1360 * @param flags flags; none are currently defined
1361 * @return the non-negative stream number in case of success,
1362 * AVERROR_STREAM_NOT_FOUND if no stream with the requested type
1363 * could be found,
1364 * AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
1365 * @note If av_find_best_stream returns successfully and decoder_ret is not
1366 * NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
1367 */
1368 int av_find_best_stream(AVFormatContext *ic,
1369 enum AVMediaType type,
1370 int wanted_stream_nb,
1371 int related_stream,
1372 AVCodec **decoder_ret,
1373 int flags);
1374
1375 /**
1376 * Return the next frame of a stream.
1377 * This function returns what is stored in the file, and does not validate
1378 * that what is there are valid frames for the decoder. It will split what is
1379 * stored in the file into frames and return one for each call. It will not
1380 * omit invalid data between valid frames so as to give the decoder the maximum
1381 * information possible for decoding.
1382 *
1383 * If pkt->buf is NULL, then the packet is valid until the next
1384 * av_read_frame() or until avformat_close_input(). Otherwise the packet
1385 * is valid indefinitely. In both cases the packet must be freed with
1386 * av_free_packet when it is no longer needed. For video, the packet contains
1387 * exactly one frame. For audio, it contains an integer number of frames if each
1388 * frame has a known fixed size (e.g. PCM or ADPCM data). If the audio frames
1389 * have a variable size (e.g. MPEG audio), then it contains one frame.
1390 *
1391 * pkt->pts, pkt->dts and pkt->duration are always set to correct
1392 * values in AVStream.time_base units (and guessed if the format cannot
1393 * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
1394 * has B-frames, so it is better to rely on pkt->dts if you do not
1395 * decompress the payload.
1396 *
1397 * @return 0 if OK, < 0 on error or end of file
1398 */
1399 int av_read_frame(AVFormatContext *s, AVPacket *pkt);
1400
1401 /**
1402 * Seek to the keyframe at timestamp.
1403 * 'timestamp' in 'stream_index'.
1404 * @param stream_index If stream_index is (-1), a default
1405 * stream is selected, and timestamp is automatically converted
1406 * from AV_TIME_BASE units to the stream specific time_base.
1407 * @param timestamp Timestamp in AVStream.time_base units
1408 * or, if no stream is specified, in AV_TIME_BASE units.
1409 * @param flags flags which select direction and seeking mode
1410 * @return >= 0 on success
1411 */
1412 int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
1413 int flags);
1414
1415 /**
1416 * Seek to timestamp ts.
1417 * Seeking will be done so that the point from which all active streams
1418 * can be presented successfully will be closest to ts and within min/max_ts.
1419 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
1420 *
1421 * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
1422 * are the file position (this may not be supported by all demuxers).
1423 * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
1424 * in the stream with stream_index (this may not be supported by all demuxers).
1425 * Otherwise all timestamps are in units of the stream selected by stream_index
1426 * or if stream_index is -1, in AV_TIME_BASE units.
1427 * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
1428 * keyframes (this may not be supported by all demuxers).
1429 *
1430 * @param stream_index index of the stream which is used as time base reference
1431 * @param min_ts smallest acceptable timestamp
1432 * @param ts target timestamp
1433 * @param max_ts largest acceptable timestamp
1434 * @param flags flags
1435 * @return >=0 on success, error code otherwise
1436 *
1437 * @note This is part of the new seek API which is still under construction.
1438 * Thus do not use this yet. It may change at any time, do not expect
1439 * ABI compatibility yet!
1440 */
1441 int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
1442
1443 /**
1444 * Start playing a network-based stream (e.g. RTSP stream) at the
1445 * current position.
1446 */
1447 int av_read_play(AVFormatContext *s);
1448
1449 /**
1450 * Pause a network-based stream (e.g. RTSP stream).
1451 *
1452 * Use av_read_play() to resume it.
1453 */
1454 int av_read_pause(AVFormatContext *s);
1455
1456 /**
1457 * Close an opened input AVFormatContext. Free it and all its contents
1458 * and set *s to NULL.
1459 */
1460 void avformat_close_input(AVFormatContext **s);
1461 /**
1462 * @}
1463 */
1464
1465 #define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
1466 #define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
1467 #define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
1468 #define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
1469
1470 /**
1471 * @addtogroup lavf_encoding
1472 * @{
1473 */
1474 /**
1475 * Allocate the stream private data and write the stream header to
1476 * an output media file.
1477 *
1478 * @param s Media file handle, must be allocated with avformat_alloc_context().
1479 * Its oformat field must be set to the desired output format;
1480 * Its pb field must be set to an already opened AVIOContext.
1481 * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
1482 * On return this parameter will be destroyed and replaced with a dict containing
1483 * options that were not found. May be NULL.
1484 *
1485 * @return 0 on success, negative AVERROR on failure.
1486 *
1487 * @see av_opt_find, av_dict_set, avio_open, av_oformat_next.
1488 */
1489 int avformat_write_header(AVFormatContext *s, AVDictionary **options);
1490
1491 /**
1492 * Write a packet to an output media file.
1493 *
1494 * This function passes the packet directly to the muxer, without any buffering
1495 * or reordering. The caller is responsible for correctly interleaving the
1496 * packets if the format requires it. Callers that want libavformat to handle
1497 * the interleaving should call av_interleaved_write_frame() instead of this
1498 * function.
1499 *
1500 * @param s media file handle
1501 * @param pkt @parblock
1502 * The packet containing the data to be written. Note that unlike
1503 * av_interleaved_write_frame(), this function does not take
1504 * ownership of the packet passed to it (though some muxers may make
1505 * an internal reference to the input packet).
1506 *
1507 * This parameter can be NULL (at any time, not just at the end), in
1508 * order to immediately flush data buffered within the muxer, for
1509 * muxers that buffer up data internally before writing it to the
1510 * output.
1511 *
1512 * Packet's @ref AVPacket.stream_index "stream_index" field must be
1513 * set to the index of the corresponding stream in @ref
1514 * AVFormatContext.streams "s->streams". It is very strongly
1515 * recommended that timing information (@ref AVPacket.pts "pts", @ref
1516 * AVPacket.dts "dts", @ref AVPacket.duration "duration") is set to
1517 * correct values.
1518 * @endparblock
1519 * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
1520 *
1521 * @see av_interleaved_write_frame()
1522 */
1523 int av_write_frame(AVFormatContext *s, AVPacket *pkt);
1524
1525 /**
1526 * Write a packet to an output media file ensuring correct interleaving.
1527 *
1528 * This function will buffer the packets internally as needed to make sure the
1529 * packets in the output file are properly interleaved in the order of
1530 * increasing dts. Callers doing their own interleaving should call
1531 * av_write_frame() instead of this function.
1532 *
1533 * @param s media file handle
1534 * @param pkt @parblock
1535 * The packet containing the data to be written.
1536 *
1537 * If the packet is reference-counted, this function will take
1538 * ownership of this reference and unreference it later when it sees
1539 * fit.
1540 * The caller must not access the data through this reference after
1541 * this function returns. If the packet is not reference-counted,
1542 * libavformat will make a copy.
1543 *
1544 * This parameter can be NULL (at any time, not just at the end), to
1545 * flush the interleaving queues.
1546 *
1547 * Packet's @ref AVPacket.stream_index "stream_index" field must be
1548 * set to the index of the corresponding stream in @ref
1549 * AVFormatContext.streams "s->streams". It is very strongly
1550 * recommended that timing information (@ref AVPacket.pts "pts", @ref
1551 * AVPacket.dts "dts", @ref AVPacket.duration "duration") is set to
1552 * correct values.
1553 * @endparblock
1554 *
1555 * @return 0 on success, a negative AVERROR on error.
1556 *
1557 * @see av_write_frame(), AVFormatContext.max_interleave_delta
1558 */
1559 int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
1560
1561 /**
1562 * Write the stream trailer to an output media file and free the
1563 * file private data.
1564 *
1565 * May only be called after a successful call to avformat_write_header.
1566 *
1567 * @param s media file handle
1568 * @return 0 if OK, AVERROR_xxx on error
1569 */
1570 int av_write_trailer(AVFormatContext *s);
1571
1572 /**
1573 * Return the output format in the list of registered output formats
1574 * which best matches the provided parameters, or return NULL if
1575 * there is no match.
1576 *
1577 * @param short_name if non-NULL checks if short_name matches with the
1578 * names of the registered formats
1579 * @param filename if non-NULL checks if filename terminates with the
1580 * extensions of the registered formats
1581 * @param mime_type if non-NULL checks if mime_type matches with the
1582 * MIME type of the registered formats
1583 */
1584 AVOutputFormat *av_guess_format(const char *short_name,
1585 const char *filename,
1586 const char *mime_type);
1587
1588 /**
1589 * Guess the codec ID based upon muxer and filename.
1590 */
1591 enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
1592 const char *filename, const char *mime_type,
1593 enum AVMediaType type);
1594
1595 /**
1596 * @}
1597 */
1598
1599
1600 /**
1601 * @defgroup lavf_misc Utility functions
1602 * @ingroup libavf
1603 * @{
1604 *
1605 * Miscellaneous utility functions related to both muxing and demuxing
1606 * (or neither).
1607 */
1608
1609 /**
1610 * Send a nice hexadecimal dump of a buffer to the specified file stream.
1611 *
1612 * @param f The file stream pointer where the dump should be sent to.
1613 * @param buf buffer
1614 * @param size buffer size
1615 *
1616 * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
1617 */
1618 void av_hex_dump(FILE *f, const uint8_t *buf, int size);
1619
1620 /**
1621 * Send a nice hexadecimal dump of a buffer to the log.
1622 *
1623 * @param avcl A pointer to an arbitrary struct of which the first field is a
1624 * pointer to an AVClass struct.
1625 * @param level The importance level of the message, lower values signifying
1626 * higher importance.
1627 * @param buf buffer
1628 * @param size buffer size
1629 *
1630 * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
1631 */
1632 void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
1633
1634 /**
1635 * Send a nice dump of a packet to the specified file stream.
1636 *
1637 * @param f The file stream pointer where the dump should be sent to.
1638 * @param pkt packet to dump
1639 * @param dump_payload True if the payload must be displayed, too.
1640 * @param st AVStream that the packet belongs to
1641 */
1642 void av_pkt_dump2(FILE *f, AVPacket *pkt, int dump_payload, AVStream *st);
1643
1644
1645 /**
1646 * Send a nice dump of a packet to the log.
1647 *
1648 * @param avcl A pointer to an arbitrary struct of which the first field is a
1649 * pointer to an AVClass struct.
1650 * @param level The importance level of the message, lower values signifying
1651 * higher importance.
1652 * @param pkt packet to dump
1653 * @param dump_payload True if the payload must be displayed, too.
1654 * @param st AVStream that the packet belongs to
1655 */
1656 void av_pkt_dump_log2(void *avcl, int level, AVPacket *pkt, int dump_payload,
1657 AVStream *st);
1658
1659 /**
1660 * Get the AVCodecID for the given codec tag tag.
1661 * If no codec id is found returns AV_CODEC_ID_NONE.
1662 *
1663 * @param tags list of supported codec_id-codec_tag pairs, as stored
1664 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
1665 */
1666 enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
1667
1668 /**
1669 * Get the codec tag for the given codec id id.
1670 * If no codec tag is found returns 0.
1671 *
1672 * @param tags list of supported codec_id-codec_tag pairs, as stored
1673 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
1674 */
1675 unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id);
1676
1677 int av_find_default_stream_index(AVFormatContext *s);
1678
1679 /**
1680 * Get the index for a specific timestamp.
1681 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
1682 * to the timestamp which is <= the requested one, if backward
1683 * is 0, then it will be >=
1684 * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
1685 * @return < 0 if no such timestamp could be found
1686 */
1687 int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
1688
1689 /**
1690 * Add an index entry into a sorted list. Update the entry if the list
1691 * already contains it.
1692 *
1693 * @param timestamp timestamp in the time base of the given stream
1694 */
1695 int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
1696 int size, int distance, int flags);
1697
1698
1699 /**
1700 * Split a URL string into components.
1701 *
1702 * The pointers to buffers for storing individual components may be null,
1703 * in order to ignore that component. Buffers for components not found are
1704 * set to empty strings. If the port is not found, it is set to a negative
1705 * value.
1706 *
1707 * @param proto the buffer for the protocol
1708 * @param proto_size the size of the proto buffer
1709 * @param authorization the buffer for the authorization
1710 * @param authorization_size the size of the authorization buffer
1711 * @param hostname the buffer for the host name
1712 * @param hostname_size the size of the hostname buffer
1713 * @param port_ptr a pointer to store the port number in
1714 * @param path the buffer for the path
1715 * @param path_size the size of the path buffer
1716 * @param url the URL to split
1717 */
1718 void av_url_split(char *proto, int proto_size,
1719 char *authorization, int authorization_size,
1720 char *hostname, int hostname_size,
1721 int *port_ptr,
1722 char *path, int path_size,
1723 const char *url);
1724
1725
1726 void av_dump_format(AVFormatContext *ic,
1727 int index,
1728 const char *url,
1729 int is_output);
1730
1731 /**
1732 * Return in 'buf' the path with '%d' replaced by a number.
1733 *
1734 * Also handles the '%0nd' format where 'n' is the total number
1735 * of digits and '%%'.
1736 *
1737 * @param buf destination buffer
1738 * @param buf_size destination buffer size
1739 * @param path numbered sequence string
1740 * @param number frame number
1741 * @return 0 if OK, -1 on format error
1742 */
1743 int av_get_frame_filename(char *buf, int buf_size,
1744 const char *path, int number);
1745
1746 /**
1747 * Check whether filename actually is a numbered sequence generator.
1748 *
1749 * @param filename possible numbered sequence string
1750 * @return 1 if a valid numbered sequence string, 0 otherwise
1751 */
1752 int av_filename_number_test(const char *filename);
1753
1754 /**
1755 * Generate an SDP for an RTP session.
1756 *
1757 * Note, this overwrites the id values of AVStreams in the muxer contexts
1758 * for getting unique dynamic payload types.
1759 *
1760 * @param ac array of AVFormatContexts describing the RTP streams. If the
1761 * array is composed by only one context, such context can contain
1762 * multiple AVStreams (one AVStream per RTP stream). Otherwise,
1763 * all the contexts in the array (an AVCodecContext per RTP stream)
1764 * must contain only one AVStream.
1765 * @param n_files number of AVCodecContexts contained in ac
1766 * @param buf buffer where the SDP will be stored (must be allocated by
1767 * the caller)
1768 * @param size the size of the buffer
1769 * @return 0 if OK, AVERROR_xxx on error
1770 */
1771 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
1772
1773 /**
1774 * Return a positive value if the given filename has one of the given
1775 * extensions, 0 otherwise.
1776 *
1777 * @param extensions a comma-separated list of filename extensions
1778 */
1779 int av_match_ext(const char *filename, const char *extensions);
1780
1781 /**
1782 * Test if the given container can store a codec.
1783 *
1784 * @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
1785 *
1786 * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
1787 * A negative number if this information is not available.
1788 */
1789 int avformat_query_codec(AVOutputFormat *ofmt, enum AVCodecID codec_id, int std_compliance);
1790
1791 /**
1792 * @defgroup riff_fourcc RIFF FourCCs
1793 * @{
1794 * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
1795 * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
1796 * following code:
1797 * @code
1798 * uint32_t tag = MKTAG('H', '2', '6', '4');
1799 * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
1800 * enum AVCodecID id = av_codec_get_id(table, tag);
1801 * @endcode
1802 */
1803 /**
1804 * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
1805 */
1806 const struct AVCodecTag *avformat_get_riff_video_tags(void);
1807 /**
1808 * @return the table mapping RIFF FourCCs for audio to AVCodecID.
1809 */
1810 const struct AVCodecTag *avformat_get_riff_audio_tags(void);
1811 /**
1812 * @}
1813 */
1814
1815 /**
1816 * @}
1817 */
1818
1819 #endif /* AVFORMAT_AVFORMAT_H */