1 /*
2 * copyright (c) 2001 Fabrice Bellard
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 Libavformat 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 AVStream.time_base "stream timebase" should
198 * be set to the timebase that the caller desires to use for this stream (note
199 * that the timebase actually used by the muxer can be different, as will be
200 * described later).
201 * - It is advised to manually initialize only the relevant fields in
202 * AVCodecContext, rather than using @ref avcodec_copy_context() during
203 * remuxing: there is no guarantee that the codec context values remain valid
204 * for both input and output format contexts.
205 * - The caller may fill in additional information, such as @ref
206 * AVFormatContext.metadata "global" or @ref AVStream.metadata "per-stream"
207 * metadata, @ref AVFormatContext.chapters "chapters", @ref
208 * AVFormatContext.programs "programs", etc. as described in the
209 * AVFormatContext documentation. Whether such information will actually be
210 * stored in the output depends on what the container format and the muxer
211 * support.
212 *
213 * When the muxing context is fully set up, the caller must call
214 * avformat_write_header() to initialize the muxer internals and write the file
215 * header. Whether anything actually is written to the IO context at this step
216 * depends on the muxer, but this function must always be called. Any muxer
217 * private options must be passed in the options parameter to this function.
218 *
219 * The data is then sent to the muxer by repeatedly calling av_write_frame() or
220 * av_interleaved_write_frame() (consult those functions' documentation for
221 * discussion on the difference between them; only one of them may be used with
222 * a single muxing context, they should not be mixed). Do note that the timing
223 * information on the packets sent to the muxer must be in the corresponding
224 * AVStream's timebase. That timebase is set by the muxer (in the
225 * avformat_write_header() step) and may be different from the timebase
226 * requested by the caller.
227 *
228 * Once all the data has been written, the caller must call av_write_trailer()
229 * to flush any buffered packets and finalize the output file, then close the IO
230 * context (if any) and finally free the muxing context with
231 * avformat_free_context().
232 * @}
233 *
234 * @defgroup lavf_io I/O Read/Write
235 * @{
236 * @}
237 *
238 * @defgroup lavf_codec Demuxers
239 * @{
240 * @defgroup lavf_codec_native Native Demuxers
241 * @{
242 * @}
243 * @defgroup lavf_codec_wrappers External library wrappers
244 * @{
245 * @}
246 * @}
247 * @defgroup lavf_protos I/O Protocols
248 * @{
249 * @}
250 * @defgroup lavf_internal Internal
251 * @{
252 * @}
253 * @}
254 *
255 */
256
258 #include <stdio.h> /* FILE */
262
265
267
270
271 /**
272 * @defgroup metadata_api Public Metadata API
273 * @{
274 * @ingroup libavf
275 * The metadata API allows libavformat to export metadata tags to a client
276 * application when demuxing. Conversely it allows a client application to
277 * set metadata when muxing.
278 *
279 * Metadata is exported or set as pairs of key/value strings in the 'metadata'
280 * fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
281 * using the @ref lavu_dict "AVDictionary" API. Like all strings in FFmpeg,
282 * metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
283 * exported by demuxers isn't checked to be valid UTF-8 in most cases.
284 *
285 * Important concepts to keep in mind:
286 * - Keys are unique; there can never be 2 tags with the same key. This is
287 * also meant semantically, i.e., a demuxer should not knowingly produce
288 * several keys that are literally different but semantically identical.
289 * E.g., key=Author5, key=Author6. In this example, all authors must be
290 * placed in the same tag.
291 * - Metadata is flat, not hierarchical; there are no subtags. If you
292 * want to store, e.g., the email address of the child of producer Alice
293 * and actor Bob, that could have key=alice_and_bobs_childs_email_address.
294 * - Several modifiers can be applied to the tag name. This is done by
295 * appending a dash character ('-') and the modifier name in the order
296 * they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
297 * - language -- a tag whose value is localized for a particular language
298 * is appended with the ISO 639-2/B 3-letter language code.
299 * For example: Author-ger=Michael, Author-eng=Mike
300 * The original/default language is in the unqualified "Author" tag.
301 * A demuxer should set a default if it sets any translated tag.
302 * - sorting -- a modified version of a tag that should be used for
303 * sorting will have '-sort' appended. E.g. artist="The Beatles",
304 * artist-sort="Beatles, The".
305 * - Some protocols and demuxers support metadata updates. After a successful
306 * call to av_read_packet(), AVFormatContext.event_flags or AVStream.event_flags
307 * will be updated to indicate if metadata changed. In order to detect metadata
308 * changes on a stream, you need to loop through all streams in the AVFormatContext
309 * and check their individual event_flags.
310 *
311 * - Demuxers attempt to export metadata in a generic format, however tags
312 * with no generic equivalents are left as they are stored in the container.
313 * Follows a list of generic tag names:
314 *
315 @verbatim
316 album -- name of the set this work belongs to
317 album_artist -- main creator of the set/album, if different from artist.
318 e.g. "Various Artists" for compilation albums.
319 artist -- main creator of the work
320 comment -- any additional description of the file.
321 composer -- who composed the work, if different from artist.
322 copyright -- name of copyright holder.
323 creation_time-- date when the file was created, preferably in ISO 8601.
324 date -- date when the work was created, preferably in ISO 8601.
325 disc -- number of a subset, e.g. disc in a multi-disc collection.
326 encoder -- name/settings of the software/hardware that produced the file.
327 encoded_by -- person/group who created the file.
328 filename -- original name of the file.
329 genre -- <self-evident>.
330 language -- main language in which the work is performed, preferably
331 in ISO 639-2 format. Multiple languages can be specified by
332 separating them with commas.
333 performer -- artist who performed the work, if different from artist.
334 E.g for "Also sprach Zarathustra", artist would be "Richard
335 Strauss" and performer "London Philharmonic Orchestra".
336 publisher -- name of the label/publisher.
337 service_name -- name of the service in broadcasting (channel name).
338 service_provider -- name of the service provider in broadcasting.
339 title -- name of the work.
340 track -- number of this work in the set, can be in form current/total.
341 variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
342 @endverbatim
343 *
344 * Look in the examples section for an application example how to use the Metadata API.
345 *
346 * @}
347 */
348
349 /* packet functions */
350
351
352 /**
353 * Allocate and read the payload of a packet and initialize its
354 * fields with default values.
355 *
356 * @param s associated IO context
357 * @param pkt packet
358 * @param size desired payload size
359 * @return >0 (read size) if OK, AVERROR_xxx otherwise
360 */
362
363
364 /**
365 * Read data and append it to the current content of the AVPacket.
366 * If pkt->size is 0 this is identical to av_get_packet.
367 * Note that this uses av_grow_packet and thus involves a realloc
368 * which is inefficient. Thus this function should only be used
369 * when there is no reasonable way to know (an upper bound of)
370 * the final size.
371 *
372 * @param s associated IO context
373 * @param pkt packet
374 * @param size amount of data to read
375 * @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
376 * will not be lost even if an error occurs.
377 */
379
380 #if FF_API_LAVF_FRAC
381 /*************************************************/
382 /* fractional numbers for exact pts handling */
383
384 /**
385 * The exact value of the fractional number is: 'val + num / den'.
386 * num is assumed to be 0 <= num < den.
387 */
388 typedef struct AVFrac {
389 int64_t
val, num, den;
390 } AVFrac;
391 #endif
392
393 /*************************************************/
394 /* input/output formats */
395
397
398 /**
399 * This structure contains the data a format has to probe a file.
400 */
403 unsigned char *
buf;
/**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */
404 int buf_size;
/**< Size of buf except extra allocated bytes */
407
408 #define AVPROBE_SCORE_RETRY (AVPROBE_SCORE_MAX/4)
409 #define AVPROBE_SCORE_STREAM_RETRY (AVPROBE_SCORE_MAX/4-1)
410
411 #define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension
412 #define AVPROBE_SCORE_MIME 75
///< score for file mime type
413 #define AVPROBE_SCORE_MAX 100
///< maximum score
414
415 #define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
416
417 /// Demuxer will use avio_open, no opened file should be provided by the caller.
418 #define AVFMT_NOFILE 0x0001
419 #define AVFMT_NEEDNUMBER 0x0002 /**< Needs '%d' in filename. */
420 #define AVFMT_SHOW_IDS 0x0008 /**< Show format stream IDs numbers. */
421 #define AVFMT_RAWPICTURE 0x0020 /**< Format wants AVPicture structure for
422 raw picture data. */
423 #define AVFMT_GLOBALHEADER 0x0040 /**< Format wants global header. */
424 #define AVFMT_NOTIMESTAMPS 0x0080 /**< Format does not need / have any timestamps. */
425 #define AVFMT_GENERIC_INDEX 0x0100 /**< Use generic index building code. */
426 #define AVFMT_TS_DISCONT 0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
427 #define AVFMT_VARIABLE_FPS 0x0400 /**< Format allows variable fps. */
428 #define AVFMT_NODIMENSIONS 0x0800 /**< Format does not need width/height */
429 #define AVFMT_NOSTREAMS 0x1000 /**< Format does not require any streams */
430 #define AVFMT_NOBINSEARCH 0x2000 /**< Format does not allow to fall back on binary search via read_timestamp */
431 #define AVFMT_NOGENSEARCH 0x4000 /**< Format does not allow to fall back on generic search */
432 #define AVFMT_NO_BYTE_SEEK 0x8000 /**< Format does not allow seeking by bytes */
433 #define AVFMT_ALLOW_FLUSH 0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
434 #if LIBAVFORMAT_VERSION_MAJOR <= 54
435 #define AVFMT_TS_NONSTRICT 0x8020000 //we try to be compatible to the ABIs of ffmpeg and major forks
436 #else
437 #define AVFMT_TS_NONSTRICT 0x20000
438 #endif
439 /**< Format does not require strictly
440 increasing timestamps, but they must
441 still be monotonic */
442 #define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative
443 timestamps. If not set the timestamp
444 will be shifted in av_write_frame and
445 av_interleaved_write_frame so they
446 start from 0.
447 The user or muxer can override this through
448 AVFormatContext.avoid_negative_ts
449 */
450
451 #define AVFMT_SEEK_TO_PTS 0x4000000 /**< Seeking is based on PTS */
452
453 /**
454 * @addtogroup lavf_encoding
455 * @{
456 */
459 /**
460 * Descriptive name for the format, meant to be more human-readable
461 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
462 * to define it.
463 */
466 const char *
extensions;
/**< comma-separated filename extensions */
467 /* output support */
471 /**
472 * can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_RAWPICTURE,
473 * AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
474 * AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
475 * AVFMT_TS_NONSTRICT
476 */
478
479 /**
480 * List of supported codec_id-codec_tag pairs, ordered by "better
481 * choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
482 */
484
485
487
488 /*****************************************************************
489 * No fields below this line are part of the public API. They
490 * may not be used outside of libavformat and can be changed and
491 * removed at will.
492 * New public fields should be added right above.
493 *****************************************************************
494 */
496 /**
497 * size of private data so that it can be allocated in the wrapper
498 */
500
502 /**
503 * Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,
504 * pkt can be NULL in order to flush data buffered in the muxer.
505 * When flushing, return 0 if there still is more data to flush,
506 * or 1 if everything was flushed and there is no more buffered
507 * data.
508 */
511 /**
512 * Currently only used to set pixel format if not YUV420P.
513 */
516 /**
517 * Test if the given codec can be stored in this container.
518 *
519 * @return 1 if the codec is supported, 0 if it is not.
520 * A negative number if unknown.
521 * MKTAG('A', 'P', 'I', 'C') if the codec is only supported as AV_DISPOSITION_ATTACHED_PIC
522 */
524
526 int64_t *dts, int64_t *wall);
527 /**
528 * Allows sending messages from application to device.
529 */
531 void *
data,
size_t data_size);
532
533 /**
534 * Write an uncoded AVFrame.
535 *
536 * See av_write_uncoded_frame() for details.
537 *
538 * The library will free *frame afterwards, but the muxer can prevent it
539 * by setting the pointer to NULL.
540 */
543 /**
544 * Returns device list with it properties.
545 * @see avdevice_list_devices() for more details.
546 */
548 /**
549 * Initialize device capabilities submodule.
550 * @see avdevice_capabilities_create() for more details.
551 */
553 /**
554 * Free device capabilities submodule.
555 * @see avdevice_capabilities_free() for more details.
556 */
560 /**
561 * @}
562 */
563
564 /**
565 * @addtogroup lavf_decoding
566 * @{
567 */
569 /**
570 * A comma separated list of short names for the format. New names
571 * may be appended with a minor bump.
572 */
574
575 /**
576 * Descriptive name for the format, meant to be more human-readable
577 * than name. You should use the NULL_IF_CONFIG_SMALL() macro
578 * to define it.
579 */
581
582 /**
583 * Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
584 * AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
585 * AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK, AVFMT_SEEK_TO_PTS.
586 */
588
589 /**
590 * If extensions are defined, then no probe is done. You should
591 * usually not use extension format guessing because it is not
592 * reliable enough
593 */
595
597
599
600 /**
601 * Comma-separated list of mime types.
602 * It is used check for matching mime types while probing.
603 * @see av_probe_input_format2
604 */
606
607 /*****************************************************************
608 * No fields below this line are part of the public API. They
609 * may not be used outside of libavformat and can be changed and
610 * removed at will.
611 * New public fields should be added right above.
612 *****************************************************************
613 */
615
616 /**
617 * Raw demuxers store their codec ID here.
618 */
620
621 /**
622 * Size of private data so that it can be allocated in the wrapper.
623 */
625
626 /**
627 * Tell if a given file has a chance of being parsed as this format.
628 * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
629 * big so you do not have to check for that unless you need more.
630 */
632
633 /**
634 * Read the format header and initialize the AVFormatContext
635 * structure. Return 0 if OK. 'avformat_new_stream' should be
636 * called to create new streams.
637 */
639
640 /**
641 * Read one packet and put it in 'pkt'. pts and flags are also
642 * set. 'avformat_new_stream' can be called only if the flag
643 * AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
644 * background thread).
645 * @return 0 on success, < 0 on error.
646 * When returning an error, pkt must not have been allocated
647 * or must be freed before returning
648 */
650
651 /**
652 * Close the stream. The AVFormatContext and AVStreams are not
653 * freed by this function
654 */
656
657 /**
658 * Seek to a given timestamp relative to the frames in
659 * stream component stream_index.
660 * @param stream_index Must not be -1.
661 * @param flags Selects which direction should be preferred if no exact
662 * match is available.
663 * @return >= 0 on success (but not necessarily the new offset)
664 */
666 int stream_index, int64_t timestamp,
int flags);
667
668 /**
669 * Get the next timestamp in stream[stream_index].time_base units.
670 * @return the timestamp or AV_NOPTS_VALUE if an error occurred
671 */
673 int64_t *pos, int64_t pos_limit);
674
675 /**
676 * Start/resume playing - only meaningful if using a network-based format
677 * (RTSP).
678 */
680
681 /**
682 * Pause playing - only meaningful if using a network-based format
683 * (RTSP).
684 */
686
687 /**
688 * Seek to timestamp ts.
689 * Seeking will be done so that the point from which all active streams
690 * can be presented successfully will be closest to ts and within min/max_ts.
691 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
692 */
694
695 /**
696 * Returns device list with it properties.
697 * @see avdevice_list_devices() for more details.
698 */
700
701 /**
702 * Initialize device capabilities submodule.
703 * @see avdevice_capabilities_create() for more details.
704 */
706
707 /**
708 * Free device capabilities submodule.
709 * @see avdevice_capabilities_free() for more details.
710 */
713 /**
714 * @}
715 */
716
724 this assumes that each packet in the file contains no demuxer level headers and
725 just codec level data, otherwise position generation would fail */
726 };
727
731 * Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are available
732 * when seeking to this entry. That means preferable PTS on keyframe based formats.
733 * But demuxers can choose to store a different timestamp, if it is more convenient for the implementation or nothing better
734 * is known
735 */
736 #define AVINDEX_KEYFRAME 0x0001
738 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).
739 int min_distance;
/**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */
741
742 #define AV_DISPOSITION_DEFAULT 0x0001
743 #define AV_DISPOSITION_DUB 0x0002
744 #define AV_DISPOSITION_ORIGINAL 0x0004
745 #define AV_DISPOSITION_COMMENT 0x0008
746 #define AV_DISPOSITION_LYRICS 0x0010
747 #define AV_DISPOSITION_KARAOKE 0x0020
748
749 /**
750 * Track should be used during playback by default.
751 * Useful for subtitle track that should be displayed
752 * even when user did not explicitly ask for subtitles.
753 */
754 #define AV_DISPOSITION_FORCED 0x0040
755 #define AV_DISPOSITION_HEARING_IMPAIRED 0x0080 /**< stream for hearing impaired audiences */
756 #define AV_DISPOSITION_VISUAL_IMPAIRED 0x0100 /**< stream for visual impaired audiences */
757 #define AV_DISPOSITION_CLEAN_EFFECTS 0x0200 /**< stream without voice */
758 /**
759 * The stream is stored in the file as an attached picture/"cover art" (e.g.
760 * APIC frame in ID3v2). The single packet associated with it will be returned
761 * among the first few packets read from the file unless seeking takes place.
762 * It can also be accessed at any time in AVStream.attached_pic.
763 */
764 #define AV_DISPOSITION_ATTACHED_PIC 0x0400
765
766 /**
767 * To specify text track kind (different from subtitles default).
768 */
769 #define AV_DISPOSITION_CAPTIONS 0x10000
770 #define AV_DISPOSITION_DESCRIPTIONS 0x20000
771 #define AV_DISPOSITION_METADATA 0x40000
772
773 /**
774 * Options for behavior on timestamp wrap detection.
775 */
776 #define AV_PTS_WRAP_IGNORE 0 ///< ignore the wrap
777 #define AV_PTS_WRAP_ADD_OFFSET 1
///< add the format specific offset on wrap detection
778 #define AV_PTS_WRAP_SUB_OFFSET -1
///< subtract the format specific offset on wrap detection
779
780 /**
781 * Stream structure.
782 * New fields can be added to the end with minor version bumps.
783 * Removal, reordering and changes to existing fields require a major
784 * version bump.
785 * sizeof(AVStream) must not be used outside libav*.
786 */
788 int index;
/**< stream index in AVFormatContext */
789 /**
790 * Format-specific stream ID.
791 * decoding: set by libavformat
792 * encoding: set by the user, replaced by libavformat if left unset
793 */
795 /**
796 * Codec context associated with this stream. Allocated and freed by
797 * libavformat.
798 *
799 * - decoding: The demuxer exports codec information stored in the headers
800 * here.
801 * - encoding: The user sets codec information, the muxer writes it to the
802 * output. Mandatory fields as specified in AVCodecContext
803 * documentation must be set even if this AVCodecContext is
804 * not actually used for encoding.
805 */
808
809 #if FF_API_LAVF_FRAC
810 /**
811 * @deprecated this field is unused
812 */
815 #endif
816
817 /**
818 * This is the fundamental unit of time (in seconds) in terms
819 * of which frame timestamps are represented.
820 *
821 * decoding: set by libavformat
822 * encoding: May be set by the caller before avformat_write_header() to
823 * provide a hint to the muxer about the desired timebase. In
824 * avformat_write_header(), the muxer will overwrite this field
825 * with the timebase that will actually be used for the timestamps
826 * written into the file (which may or may not be related to the
827 * user-provided one, depending on the format).
828 */
830
831 /**
832 * Decoding: pts of the first frame of the stream in presentation order, in stream time base.
833 * Only set this if you are absolutely 100% sure that the value you set
834 * it to really is the pts of the first frame.
835 * This may be undefined (AV_NOPTS_VALUE).
836 * @note The ASF header does NOT contain a correct start_time the ASF
837 * demuxer must NOT set this.
838 */
840
841 /**
842 * Decoding: duration of the stream, in stream time base.
843 * If a source file does not specify a duration, but does specify
844 * a bitrate, this value will be estimated from bitrate and file size.
845 */
847
848 int64_t
nb_frames;
///< number of frames in this stream if known or 0
849
851
852 enum AVDiscard discard;
///< Selects which packets can be discarded at will and do not need to be demuxed.
853
854 /**
855 * sample aspect ratio (0 if unknown)
856 * - encoding: Set by user.
857 * - decoding: Set by libavformat.
858 */
860
862
863 /**
864 * Average framerate
865 *
866 * - demuxing: May be set by libavformat when creating the stream or in
867 * avformat_find_stream_info().
868 * - muxing: May be set by the caller before avformat_write_header().
869 */
871
872 /**
873 * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
874 * will contain the attached picture.
875 *
876 * decoding: set by libavformat, must not be modified by the caller.
877 * encoding: unused
878 */
880
881 /**
882 * An array of side data that applies to the whole stream (i.e. the
883 * container does not allow it to change between packets).
884 *
885 * There may be no overlap between the side data in this array and side data
886 * in the packets. I.e. a given side data is either exported by the muxer
887 * (demuxing) / set by the caller (muxing) in this array, then it never
888 * appears in the packets, or the side data is exported / sent through
889 * the packets (always in the first packet where the value becomes known or
890 * changes), then it does not appear in this array.
891 *
892 * - demuxing: Set by libavformat when the stream is created.
893 * - muxing: May be set by the caller before avformat_write_header().
894 *
895 * Freed by libavformat in avformat_free_context().
896 *
897 * @see av_format_inject_global_side_data()
898 */
900 /**
901 * The number of elements in the AVStream.side_data array.
902 */
904
905 /**
906 * Flags for the user to detect events happening on the stream. Flags must
907 * be cleared by the user once the event has been handled.
908 * A combination of AVSTREAM_EVENT_FLAG_*.
909 */
911 #define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
912
913 /*****************************************************************
914 * All fields below this line are not part of the public API. They
915 * may not be used outside of libavformat and can be changed and
916 * removed at will.
917 * New public fields should be added right above.
918 *****************************************************************
919 */
920
921 /**
922 * Stream information used internally by av_find_stream_info()
923 */
924 #define MAX_STD_TIMEBASES (30*12+7+6)
925 struct {
933
934 /**
935 * 0 -> decoder has not been searched for yet.
936 * >0 -> decoder found
937 * <0 -> decoder with codec_id == -found_decoder has not been found
938 */
940
942
943 /**
944 * Those are used for average framerate estimation.
945 */
950
952
953 int pts_wrap_bits;
/**< number of bits in pts (used for wrapping control) */
954
955 // Timestamp generation support:
956 /**
957 * Timestamp corresponding to the last dts sync point.
958 *
959 * Initialized when AVCodecParserContext.dts_sync_point >= 0 and
960 * a DTS is received from the underlying container. Otherwise set to
961 * AV_NOPTS_VALUE by default.
962 */
967
968 /**
969 * Number of packets to buffer for codec probing
970 */
971 #define MAX_PROBE_PACKETS 2500
973
974 /**
975 * Number of frames that have been demuxed during av_find_stream_info()
976 */
978
979 /* av_read_frame() support */
982
983 /**
984 * last packet in packet_buffer for this stream when muxing.
985 */
988 #define MAX_REORDER_DELAY 16
990
992 support seeking natively. */
995
996 /**
997 * Real base framerate of the stream.
998 * This is the lowest framerate with which all timestamps can be
999 * represented accurately (it is the least common multiple of all
1000 * framerates in the stream). Note, this value is just a guess!
1001 * For example, if the time base is 1/90000 and all frames have either
1002 * approximately 3600 or 1800 timer ticks, then r_frame_rate will be 50/1.
1003 *
1004 * Code outside avformat should access this field using:
1005 * av_stream_get/set_r_frame_rate(stream)
1006 */
1008
1009 /**
1010 * Stream Identifier
1011 * This is the MPEG-TS stream identifier +1
1012 * 0 means unknown
1013 */
1015
1018
1019 /**
1020 * stream probing state
1021 * -1 -> probing finished
1022 * 0 -> no probing requested
1023 * rest -> perform probing with request_probe being the minimum score to accept.
1024 * NOT PART OF PUBLIC API
1025 */
1027 /**
1028 * Indicates that everything up to the next keyframe
1029 * should be discarded.
1030 */
1032
1033 /**
1034 * Number of samples to skip at the start of the frame decoded from the next packet.
1035 */
1037
1038 /**
1039 * If not 0, the first audio sample that should be discarded from the stream.
1040 * This is broken by design (needs global sample count), but can't be
1041 * avoided for broken by design formats such as mp3 with ad-hoc gapless
1042 * audio support.
1043 */
1045
1046 /**
1047 * The sample after last sample that is intended to be discarded after
1048 * first_discard_sample. Works on frame boundaries only. Used to prevent
1049 * early EOF if the gapless info is broken (considered concatenated mp3s).
1050 */
1052
1053 /**
1054 * Number of internally decoded frames, used internally in libavformat, do not access
1055 * its lifetime differs from info which is why it is not in that structure.
1056 */
1058
1059 /**
1060 * Timestamp offset added to timestamps before muxing
1061 * NOT PART OF PUBLIC API
1062 */
1064
1065 /**
1066 * Internal data to check for wrapping of the time stamp
1067 */
1069
1070 /**
1071 * Options for behavior, when a wrap is detected.
1072 *
1073 * Defined by AV_PTS_WRAP_ values.
1074 *
1075 * If correction is enabled, there are two possibilities:
1076 * If the first time stamp is near the wrap point, the wrap offset
1077 * will be subtracted, which will create negative time stamps.
1078 * Otherwise the offset will be added.
1079 */
1081
1082 /**
1083 * Internal data to prevent doing update_initial_durations() twice
1084 */
1086
1087 /**
1088 * Internal data to generate dts from pts
1089 */
1092
1093 /**
1094 * Internal data to analyze DTS and detect faulty mpeg streams
1095 */
1099
1100 /**
1101 * Internal data to inject global side data
1102 */
1104
1105 /**
1106 * String containing paris of key and values describing recommended encoder configuration.
1107 * Paris are separated by ','.
1108 * Keys are separated from values by '='.
1109 */
1111
1112 /**
1113 * display aspect ratio (0 if unknown)
1114 * - encoding: unused
1115 * - decoding: Set by libavformat to calculate sample_aspect_ratio internally
1116 */
1119
1125
1126 /**
1127 * Returns the pts of the last muxed packet + its duration
1128 *
1129 * the retuned value is undefined when used with a demuxer.
1130 */
1132
1133 #define AV_PROGRAM_RUNNING 1
1134
1135 /**
1136 * New fields can be added to the end with minor version bumps.
1137 * Removal, reordering and changes to existing fields require a major
1138 * version bump.
1139 * sizeof(AVProgram) must not be used outside libav*.
1140 */
1148
1152
1153 /*****************************************************************
1154 * All fields below this line are not part of the public API. They
1155 * may not be used outside of libavformat and can be changed and
1156 * removed at will.
1157 * New public fields should be added right above.
1158 *****************************************************************
1159 */
1162
1166
1167 #define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
1168 (streams are added dynamically) */
1169
1171 int id;
///< unique ID to identify the chapter
1173 int64_t
start,
end;
///< chapter start/end time in time_base units
1176
1177
1178 /**
1179 * Callback used by devices to communicate with application.
1180 */
1182 void *
data,
size_t data_size);
1183
1184
1185 /**
1186 * The duration of a video can be estimated through various ways, and this enum can be used
1187 * to know how the duration was estimated.
1188 */
1193 };
1194
1196
1197 /**
1198 * Format I/O context.
1199 * New fields can be added to the end with minor version bumps.
1200 * Removal, reordering and changes to existing fields require a major
1201 * version bump.
1202 * sizeof(AVFormatContext) must not be used outside libav*, use
1203 * avformat_alloc_context() to create an AVFormatContext.
1204 */
1206 /**
1207 * A class for logging and @ref avoptions. Set by avformat_alloc_context().
1208 * Exports (de)muxer private options if they exist.
1209 */
1211
1212 /**
1213 * The input container format.
1214 *
1215 * Demuxing only, set by avformat_open_input().
1216 */
1218
1219 /**
1220 * The output container format.
1221 *
1222 * Muxing only, must be set by the caller before avformat_write_header().
1223 */
1225
1226 /**
1227 * Format private data. This is an AVOptions-enabled struct
1228 * if and only if iformat/oformat.priv_class is not NULL.
1229 *
1230 * - muxing: set by avformat_write_header()
1231 * - demuxing: set by avformat_open_input()
1232 */
1234
1235 /**
1236 * I/O context.
1237 *
1238 * - demuxing: either set by the user before avformat_open_input() (then
1239 * the user must close it manually) or set by avformat_open_input().
1240 * - muxing: set by the user before avformat_write_header(). The caller must
1241 * take care of closing / freeing the IO context.
1242 *
1243 * Do NOT set this field if AVFMT_NOFILE flag is set in
1244 * iformat/oformat.flags. In such a case, the (de)muxer will handle
1245 * I/O in some other way and this field will be NULL.
1246 */
1248
1249 /* stream info */
1250 /**
1251 * Flags signalling stream properties. A combination of AVFMTCTX_*.
1252 * Set by libavformat.
1253 */
1255
1256 /**
1257 * Number of elements in AVFormatContext.streams.
1258 *
1259 * Set by avformat_new_stream(), must not be modified by any other code.
1260 */
1262 /**
1263 * A list of all streams in the file. New streams are created with
1264 * avformat_new_stream().
1265 *
1266 * - demuxing: streams are created by libavformat in avformat_open_input().
1267 * If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
1268 * appear in av_read_frame().
1269 * - muxing: streams are created by the user before avformat_write_header().
1270 *
1271 * Freed by libavformat in avformat_free_context().
1272 */
1274
1275 /**
1276 * input or output filename
1277 *
1278 * - demuxing: set by avformat_open_input()
1279 * - muxing: may be set by the caller before avformat_write_header()
1280 */
1282
1283 /**
1284 * Position of the first frame of the component, in
1285 * AV_TIME_BASE fractional seconds. NEVER set this value directly:
1286 * It is deduced from the AVStream values.
1287 *
1288 * Demuxing only, set by libavformat.
1289 */
1291
1292 /**
1293 * Duration of the stream, in AV_TIME_BASE fractional
1294 * seconds. Only set this value if you know none of the individual stream
1295 * durations and also do not set any of them. This is deduced from the
1296 * AVStream values if not set.
1297 *
1298 * Demuxing only, set by libavformat.
1299 */
1301
1302 /**
1303 * Total stream bitrate in bit/s, 0 if not
1304 * available. Never set it directly if the file_size and the
1305 * duration are known as FFmpeg can compute it automatically.
1306 */
1308
1311
1312 /**
1313 * Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
1314 * Set by the user before avformat_open_input() / avformat_write_header().
1315 */
1317 #define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
1318 #define AVFMT_FLAG_IGNIDX 0x0002
///< Ignore index.
1319 #define AVFMT_FLAG_NONBLOCK 0x0004
///< Do not block when reading packets from input.
1320 #define AVFMT_FLAG_IGNDTS 0x0008
///< Ignore DTS on frames that contain both DTS & PTS
1321 #define AVFMT_FLAG_NOFILLIN 0x0010
///< Do not infer any values from other values, just return what is stored in the container
1322 #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
1323 #define AVFMT_FLAG_NOBUFFER 0x0040
///< Do not buffer frames when possible
1324 #define AVFMT_FLAG_CUSTOM_IO 0x0080
///< The caller has supplied a custom AVIOContext, don't avio_close() it.
1325 #define AVFMT_FLAG_DISCARD_CORRUPT 0x0100
///< Discard frames marked corrupted
1326 #define AVFMT_FLAG_FLUSH_PACKETS 0x0200
///< Flush the AVIOContext every packet.
1327 /**
1328 * When muxing, try to avoid writing any random/volatile data to the output.
1329 * This includes any random IDs, real-time timestamps/dates, muxer version, etc.
1330 *
1331 * This flag is mainly intended for testing.
1332 */
1333 #define AVFMT_FLAG_BITEXACT 0x0400
1334 #define AVFMT_FLAG_MP4A_LATM 0x8000 ///< Enable RTP MP4A-LATM payload
1335 #define AVFMT_FLAG_SORT_DTS 0x10000
///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
1336 #define AVFMT_FLAG_PRIV_OPT 0x20000
///< Enable use of private options by delaying codec open (this could be made default once all code is converted)
1337 #define AVFMT_FLAG_KEEP_SIDE_DATA 0x40000
///< Don't merge side data but keep it separate.
1338
1339 /**
1340 * @deprecated deprecated in favor of probesize2
1341 */
1343
1344 /**
1345 * @deprecated deprecated in favor of max_analyze_duration2
1346 */
1349
1352
1355
1356 /**
1357 * Forced video codec_id.
1358 * Demuxing: Set by user.
1359 */
1361
1362 /**
1363 * Forced audio codec_id.
1364 * Demuxing: Set by user.
1365 */
1367
1368 /**
1369 * Forced subtitle codec_id.
1370 * Demuxing: Set by user.
1371 */
1373
1374 /**
1375 * Maximum amount of memory in bytes to use for the index of each stream.
1376 * If the index exceeds this size, entries will be discarded as
1377 * needed to maintain a smaller size. This can lead to slower or less
1378 * accurate seeking (depends on demuxer).
1379 * Demuxers for which a full in-memory index is mandatory will ignore
1380 * this.
1381 * - muxing: unused
1382 * - demuxing: set by user
1383 */
1385
1386 /**
1387 * Maximum amount of memory in bytes to use for buffering frames
1388 * obtained from realtime capture devices.
1389 */
1391
1392 /**
1393 * Number of chapters in AVChapter array.
1394 * When muxing, chapters are normally written in the file header,
1395 * so nb_chapters should normally be initialized before write_header
1396 * is called. Some muxers (e.g. mov and mkv) can also write chapters
1397 * in the trailer. To write chapters in the trailer, nb_chapters
1398 * must be zero when write_header is called and non-zero when
1399 * write_trailer is called.
1400 * - muxing: set by user
1401 * - demuxing: set by libavformat
1402 */
1405
1406 /**
1407 * Metadata that applies to the whole file.
1408 *
1409 * - demuxing: set by libavformat in avformat_open_input()
1410 * - muxing: may be set by the caller before avformat_write_header()
1411 *
1412 * Freed by libavformat in avformat_free_context().
1413 */
1415
1416 /**
1417 * Start time of the stream in real world time, in microseconds
1418 * since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
1419 * stream was captured at this real world time.
1420 * - muxing: Set by the caller before avformat_write_header(). If set to
1421 * either 0 or AV_NOPTS_VALUE, then the current wall-time will
1422 * be used.
1423 * - demuxing: Set by libavformat. AV_NOPTS_VALUE if unknown. Note that
1424 * the value may become known after some number of frames
1425 * have been received.
1426 */
1428
1429 /**
1430 * The number of frames used for determining the framerate in
1431 * avformat_find_stream_info().
1432 * Demuxing only, set by the caller before avformat_find_stream_info().
1433 */
1435
1436 /**
1437 * Error recognition; higher values will detect more errors but may
1438 * misdetect some more or less valid parts as errors.
1439 * Demuxing only, set by the caller before avformat_open_input().
1440 */
1442
1443 /**
1444 * Custom interrupt callbacks for the I/O layer.
1445 *
1446 * demuxing: set by the user before avformat_open_input().
1447 * muxing: set by the user before avformat_write_header()
1448 * (mainly useful for AVFMT_NOFILE formats). The callback
1449 * should also be passed to avio_open2() if it's used to
1450 * open the file.
1451 */
1453
1454 /**
1455 * Flags to enable debugging.
1456 */
1458 #define FF_FDEBUG_TS 0x0001
1459
1460 /**
1461 * Maximum buffering duration for interleaving.
1462 *
1463 * To ensure all the streams are interleaved correctly,
1464 * av_interleaved_write_frame() will wait until it has at least one packet
1465 * for each stream before actually writing any packets to the output file.
1466 * When some streams are "sparse" (i.e. there are large gaps between
1467 * successive packets), this can result in excessive buffering.
1468 *
1469 * This field specifies the maximum difference between the timestamps of the
1470 * first and the last packet in the muxing queue, above which libavformat
1471 * will output a packet regardless of whether it has queued a packet for all
1472 * the streams.
1473 *
1474 * Muxing only, set by the caller before avformat_write_header().
1475 */
1477
1478 /**
1479 * Allow non-standard and experimental extension
1480 * @see AVCodecContext.strict_std_compliance
1481 */
1483
1484 /**
1485 * Flags for the user to detect events happening on the file. Flags must
1486 * be cleared by the user once the event has been handled.
1487 * A combination of AVFMT_EVENT_FLAG_*.
1488 */
1490 #define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.
1491
1492 /**
1493 * Maximum number of packets to read while waiting for the first timestamp.
1494 * Decoding only.
1495 */
1497
1498 /**
1499 * Avoid negative timestamps during muxing.
1500 * Any value of the AVFMT_AVOID_NEG_TS_* constants.
1501 * Note, this only works when using av_interleaved_write_frame. (interleave_packet_per_dts is in use)
1502 * - muxing: Set by user
1503 * - demuxing: unused
1504 */
1506 #define AVFMT_AVOID_NEG_TS_AUTO -1 ///< Enabled when required by target format
1507 #define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1
///< Shift timestamps so they are non negative
1508 #define AVFMT_AVOID_NEG_TS_MAKE_ZERO 2
///< Shift timestamps so that they start at 0
1509
1510 /**
1511 * Transport stream id.
1512 * This will be moved into demuxer private options. Thus no API/ABI compatibility
1513 */
1515
1516 /**
1517 * Audio preload in microseconds.
1518 * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1519 * - encoding: Set by user via AVOptions (NO direct access)
1520 * - decoding: unused
1521 */
1523
1524 /**
1525 * Max chunk time in microseconds.
1526 * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1527 * - encoding: Set by user via AVOptions (NO direct access)
1528 * - decoding: unused
1529 */
1531
1532 /**
1533 * Max chunk size in bytes
1534 * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
1535 * - encoding: Set by user via AVOptions (NO direct access)
1536 * - decoding: unused
1537 */
1539
1540 /**
1541 * forces the use of wallclock timestamps as pts/dts of packets
1542 * This has undefined results in the presence of B frames.
1543 * - encoding: unused
1544 * - decoding: Set by user via AVOptions (NO direct access)
1545 */
1547
1548 /**
1549 * avio flags, used to force AVIO_FLAG_DIRECT.
1550 * - encoding: unused
1551 * - decoding: Set by user via AVOptions (NO direct access)
1552 */
1554
1555 /**
1556 * The duration field can be estimated through various ways, and this field can be used
1557 * to know how the duration was estimated.
1558 * - encoding: unused
1559 * - decoding: Read by user via AVOptions (NO direct access)
1560 */
1562
1563 /**
1564 * Skip initial bytes when opening stream
1565 * - encoding: unused
1566 * - decoding: Set by user via AVOptions (NO direct access)
1567 */
1569
1570 /**
1571 * Correct single timestamp overflows
1572 * - encoding: unused
1573 * - decoding: Set by user via AVOptions (NO direct access)
1574 */
1576
1577 /**
1578 * Force seeking to any (also non key) frames.
1579 * - encoding: unused
1580 * - decoding: Set by user via AVOptions (NO direct access)
1581 */
1583
1584 /**
1585 * Flush the I/O context after each packet.
1586 * - encoding: Set by user via AVOptions (NO direct access)
1587 * - decoding: unused
1588 */
1590
1591 /**
1592 * format probing score.
1593 * The maximal score is AVPROBE_SCORE_MAX, its set when the demuxer probes
1594 * the format.
1595 * - encoding: unused
1596 * - decoding: set by avformat, read by user via av_format_get_probe_score() (NO direct access)
1597 */
1599
1600 /**
1601 * number of bytes to read maximally to identify format.
1602 * - encoding: unused
1603 * - decoding: set by user through AVOPtions (NO direct access)
1604 */
1606
1607 /**
1608 * ',' separated list of allowed decoders.
1609 * If NULL then all are allowed
1610 * - encoding: unused
1611 * - decoding: set by user through AVOptions (NO direct access)
1612 */
1614
1615 /**
1616 * ',' separated list of allowed demuxers.
1617 * If NULL then all are allowed
1618 * - encoding: unused
1619 * - decoding: set by user through AVOptions (NO direct access)
1620 */
1622
1623 /**
1624 * An opaque field for libavformat internal usage.
1625 * Must not be accessed in any way by callers.
1626 */
1628
1629 /**
1630 * IO repositioned flag.
1631 * This is set by avformat when the underlaying IO context read pointer
1632 * is repositioned, for example when doing byte based seeking.
1633 * Demuxers can use the flag to detect such changes.
1634 */
1636
1637 /**
1638 * Forced video codec.
1639 * This allows forcing a specific decoder, even when there are multiple with
1640 * the same codec_id.
1641 * Demuxing: Set by user via av_format_set_video_codec (NO direct access).
1642 */
1644
1645 /**
1646 * Forced audio codec.
1647 * This allows forcing a specific decoder, even when there are multiple with
1648 * the same codec_id.
1649 * Demuxing: Set by user via av_format_set_audio_codec (NO direct access).
1650 */
1652
1653 /**
1654 * Forced subtitle codec.
1655 * This allows forcing a specific decoder, even when there are multiple with
1656 * the same codec_id.
1657 * Demuxing: Set by user via av_format_set_subtitle_codec (NO direct access).
1658 */
1660
1661 /**
1662 * Forced data codec.
1663 * This allows forcing a specific decoder, even when there are multiple with
1664 * the same codec_id.
1665 * Demuxing: Set by user via av_format_set_data_codec (NO direct access).
1666 */
1668
1669 /**
1670 * Number of bytes to be written as padding in a metadata header.
1671 * Demuxing: Unused.
1672 * Muxing: Set by user via av_format_set_metadata_header_padding.
1673 */
1675
1676 /**
1677 * User data.
1678 * This is a place for some private data of the user.
1679 * Mostly usable with control_message_cb or any future callbacks in device's context.
1680 */
1682
1683 /**
1684 * Callback used by devices to communicate with application.
1685 */
1687
1688 /**
1689 * Output timestamp offset, in microseconds.
1690 * Muxing: set by user via AVOptions (NO direct access)
1691 */
1693
1694 /**
1695 * Maximum duration (in AV_TIME_BASE units) of the data read
1696 * from input in avformat_find_stream_info().
1697 * Demuxing only, set by the caller before avformat_find_stream_info()
1698 * via AVOptions (NO direct access).
1699 * Can be set to 0 to let avformat choose using a heuristic.
1700 */
1702
1703 /**
1704 * Maximum size of the data read from input for determining
1705 * the input container format.
1706 * Demuxing only, set by the caller before avformat_open_input()
1707 * via AVOptions (NO direct access).
1708 */
1710
1711 /**
1712 * dump format separator.
1713 * can be ", " or "\n " or anything else
1714 * Code outside libavformat should access this field using AVOptions
1715 * (NO direct access).
1716 * - muxing: Set by user.
1717 * - demuxing: Set by user.
1718 */
1720
1721 /**
1722 * Forced Data codec_id.
1723 * Demuxing: Set by user.
1724 */
1727
1743
1744 /**
1745 * This function will cause global side data to be injected in the next packet
1746 * of each stream as well as after any subsequent seek.
1747 */
1749
1750 /**
1751 * Returns the method used to set ctx->duration.
1752 *
1753 * @return AVFMT_DURATION_FROM_PTS, AVFMT_DURATION_FROM_STREAM, or AVFMT_DURATION_FROM_BITRATE.
1754 */
1756
1761
1762
1763 /**
1764 * @defgroup lavf_core Core functions
1765 * @ingroup libavf
1766 *
1767 * Functions for querying libavformat capabilities, allocating core structures,
1768 * etc.
1769 * @{
1770 */
1771
1772 /**
1773 * Return the LIBAVFORMAT_VERSION_INT constant.
1774 */
1776
1777 /**
1778 * Return the libavformat build-time configuration.
1779 */
1781
1782 /**
1783 * Return the libavformat license.
1784 */
1786
1787 /**
1788 * Initialize libavformat and register all the muxers, demuxers and
1789 * protocols. If you do not call this function, then you can select
1790 * exactly which formats you want to support.
1791 *
1792 * @see av_register_input_format()
1793 * @see av_register_output_format()
1794 */
1796
1799
1800 /**
1801 * Do global initialization of network components. This is optional,
1802 * but recommended, since it avoids the overhead of implicitly
1803 * doing the setup for each session.
1804 *
1805 * Calling this function will become mandatory if using network
1806 * protocols at some major version bump.
1807 */
1809
1810 /**
1811 * Undo the initialization done by avformat_network_init.
1812 */
1814
1815 /**
1816 * If f is NULL, returns the first registered input format,
1817 * if f is non-NULL, returns the next registered input format after f
1818 * or NULL if f is the last one.
1819 */
1821
1822 /**
1823 * If f is NULL, returns the first registered output format,
1824 * if f is non-NULL, returns the next registered output format after f
1825 * or NULL if f is the last one.
1826 */
1828
1829 /**
1830 * Allocate an AVFormatContext.
1831 * avformat_free_context() can be used to free the context and everything
1832 * allocated by the framework within it.
1833 */
1835
1836 /**
1837 * Free an AVFormatContext and all its streams.
1838 * @param s context to free
1839 */
1841
1842 /**
1843 * Get the AVClass for AVFormatContext. It can be used in combination with
1844 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
1845 *
1846 * @see av_opt_find().
1847 */
1849
1850 /**
1851 * Add a new stream to a media file.
1852 *
1853 * When demuxing, it is called by the demuxer in read_header(). If the
1854 * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
1855 * be called in read_packet().
1856 *
1857 * When muxing, should be called by the user before avformat_write_header().
1858 *
1859 * User is required to call avcodec_close() and avformat_free_context() to
1860 * clean up the allocation by avformat_new_stream().
1861 *
1862 * @param s media file handle
1863 * @param c If non-NULL, the AVCodecContext corresponding to the new stream
1864 * will be initialized to use this codec. This is needed for e.g. codec-specific
1865 * defaults to be set, so codec should be provided if it is known.
1866 *
1867 * @return newly created stream or NULL on error.
1868 */
1870
1871 /**
1872 * Get side information from stream.
1873 *
1874 * @param stream stream
1875 * @param type desired side information type
1876 * @param size pointer for side information size to store (optional)
1877 * @return pointer to data if present or NULL otherwise
1878 */
1881
1883
1884 /**
1885 * @}
1886 */
1887
1888
1889 /**
1890 * Allocate an AVFormatContext for an output format.
1891 * avformat_free_context() can be used to free the context and
1892 * everything allocated by the framework within it.
1893 *
1894 * @param *ctx is set to the created format context, or to NULL in
1895 * case of failure
1896 * @param oformat format to use for allocating the context, if NULL
1897 * format_name and filename are used instead
1898 * @param format_name the name of output format to use for allocating the
1899 * context, if NULL filename is used instead
1900 * @param filename the name of the filename to use for allocating the
1901 * context, may be NULL
1902 * @return >= 0 in case of success, a negative AVERROR code in case of
1903 * failure
1904 */
1906 const char *format_name, const char *filename);
1907
1908 /**
1909 * @addtogroup lavf_decoding
1910 * @{
1911 */
1912
1913 /**
1914 * Find AVInputFormat based on the short name of the input format.
1915 */
1917
1918 /**
1919 * Guess the file format.
1920 *
1921 * @param pd data to be probed
1922 * @param is_opened Whether the file is already opened; determines whether
1923 * demuxers with or without AVFMT_NOFILE are probed.
1924 */
1926
1927 /**
1928 * Guess the file format.
1929 *
1930 * @param pd data to be probed
1931 * @param is_opened Whether the file is already opened; determines whether
1932 * demuxers with or without AVFMT_NOFILE are probed.
1933 * @param score_max A probe score larger that this is required to accept a
1934 * detection, the variable is set to the actual detection
1935 * score afterwards.
1936 * If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
1937 * to retry with a larger probe buffer.
1938 */
1940
1941 /**
1942 * Guess the file format.
1943 *
1944 * @param is_opened Whether the file is already opened; determines whether
1945 * demuxers with or without AVFMT_NOFILE are probed.
1946 * @param score_ret The score of the best detection.
1947 */
1949
1950 /**
1951 * Probe a bytestream to determine the input format. Each time a probe returns
1952 * with a score that is too low, the probe buffer size is increased and another
1953 * attempt is made. When the maximum probe size is reached, the input format
1954 * with the highest score is returned.
1955 *
1956 * @param pb the bytestream to probe
1957 * @param fmt the input format is put here
1958 * @param filename the filename of the stream
1959 * @param logctx the log context
1960 * @param offset the offset within the bytestream to probe from
1961 * @param max_probe_size the maximum probe buffer size (zero for default)
1962 * @return the score in case of success, a negative value corresponding to an
1963 * the maximal score is AVPROBE_SCORE_MAX
1964 * AVERROR code otherwise
1965 */
1967 const char *filename, void *logctx,
1968 unsigned int offset,
unsigned int max_probe_size);
1969
1970 /**
1971 * Like av_probe_input_buffer2() but returns 0 on success
1972 */
1974 const char *filename, void *logctx,
1975 unsigned int offset,
unsigned int max_probe_size);
1976
1977 /**
1978 * Open an input stream and read the header. The codecs are not opened.
1979 * The stream must be closed with avformat_close_input().
1980 *
1981 * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
1982 * May be a pointer to NULL, in which case an AVFormatContext is allocated by this
1983 * function and written into ps.
1984 * Note that a user-supplied AVFormatContext will be freed on failure.
1985 * @param filename Name of the stream to open.
1986 * @param fmt If non-NULL, this parameter forces a specific input format.
1987 * Otherwise the format is autodetected.
1988 * @param options A dictionary filled with AVFormatContext and demuxer-private options.
1989 * On return this parameter will be destroyed and replaced with a dict containing
1990 * options that were not found. May be NULL.
1991 *
1992 * @return 0 on success, a negative AVERROR on failure.
1993 *
1994 * @note If you want to use custom IO, preallocate the format context and set its pb field.
1995 */
1997
2000
2001 /**
2002 * Read packets of a media file to get stream information. This
2003 * is useful for file formats with no headers such as MPEG. This
2004 * function also computes the real framerate in case of MPEG-2 repeat
2005 * frame mode.
2006 * The logical file position is not changed by this function;
2007 * examined packets may be buffered for later processing.
2008 *
2009 * @param ic media file handle
2010 * @param options If non-NULL, an ic.nb_streams long array of pointers to
2011 * dictionaries, where i-th member contains options for
2012 * codec corresponding to i-th stream.
2013 * On return each dictionary will be filled with options that were not found.
2014 * @return >=0 if OK, AVERROR_xxx on error
2015 *
2016 * @note this function isn't guaranteed to open all the codecs, so
2017 * options being non-empty at return is a perfectly normal behavior.
2018 *
2019 * @todo Let the user decide somehow what information is needed so that
2020 * we do not waste time getting stuff the user does not need.
2021 */
2023
2024 /**
2025 * Find the programs which belong to a given stream.
2026 *
2027 * @param ic media file handle
2028 * @param last the last found program, the search will start after this
2029 * program, or from the beginning if it is NULL
2030 * @param s stream index
2031 * @return the next program which belongs to s, NULL if no program is found or
2032 * the last program is not among the programs of ic.
2033 */
2035
2036 /**
2037 * Find the "best" stream in the file.
2038 * The best stream is determined according to various heuristics as the most
2039 * likely to be what the user expects.
2040 * If the decoder parameter is non-NULL, av_find_best_stream will find the
2041 * default decoder for the stream's codec; streams for which no decoder can
2042 * be found are ignored.
2043 *
2044 * @param ic media file handle
2045 * @param type stream type: video, audio, subtitles, etc.
2046 * @param wanted_stream_nb user-requested stream number,
2047 * or -1 for automatic selection
2048 * @param related_stream try to find a stream related (eg. in the same
2049 * program) to this one, or -1 if none
2050 * @param decoder_ret if non-NULL, returns the decoder for the
2051 * selected stream
2052 * @param flags flags; none are currently defined
2053 * @return the non-negative stream number in case of success,
2054 * AVERROR_STREAM_NOT_FOUND if no stream with the requested type
2055 * could be found,
2056 * AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
2057 * @note If av_find_best_stream returns successfully and decoder_ret is not
2058 * NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
2059 */
2062 int wanted_stream_nb,
2063 int related_stream,
2066
2067 /**
2068 * Return the next frame of a stream.
2069 * This function returns what is stored in the file, and does not validate
2070 * that what is there are valid frames for the decoder. It will split what is
2071 * stored in the file into frames and return one for each call. It will not
2072 * omit invalid data between valid frames so as to give the decoder the maximum
2073 * information possible for decoding.
2074 *
2075 * If pkt->buf is NULL, then the packet is valid until the next
2076 * av_read_frame() or until avformat_close_input(). Otherwise the packet
2077 * is valid indefinitely. In both cases the packet must be freed with
2078 * av_free_packet when it is no longer needed. For video, the packet contains
2079 * exactly one frame. For audio, it contains an integer number of frames if each
2080 * frame has a known fixed size (e.g. PCM or ADPCM data). If the audio frames
2081 * have a variable size (e.g. MPEG audio), then it contains one frame.
2082 *
2083 * pkt->pts, pkt->dts and pkt->duration are always set to correct
2084 * values in AVStream.time_base units (and guessed if the format cannot
2085 * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
2086 * has B-frames, so it is better to rely on pkt->dts if you do not
2087 * decompress the payload.
2088 *
2089 * @return 0 if OK, < 0 on error or end of file
2090 */
2092
2093 /**
2094 * Seek to the keyframe at timestamp.
2095 * 'timestamp' in 'stream_index'.
2096 *
2097 * @param s media file handle
2098 * @param stream_index If stream_index is (-1), a default
2099 * stream is selected, and timestamp is automatically converted
2100 * from AV_TIME_BASE units to the stream specific time_base.
2101 * @param timestamp Timestamp in AVStream.time_base units
2102 * or, if no stream is specified, in AV_TIME_BASE units.
2103 * @param flags flags which select direction and seeking mode
2104 * @return >= 0 on success
2105 */
2108
2109 /**
2110 * Seek to timestamp ts.
2111 * Seeking will be done so that the point from which all active streams
2112 * can be presented successfully will be closest to ts and within min/max_ts.
2113 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
2114 *
2115 * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
2116 * are the file position (this may not be supported by all demuxers).
2117 * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
2118 * in the stream with stream_index (this may not be supported by all demuxers).
2119 * Otherwise all timestamps are in units of the stream selected by stream_index
2120 * or if stream_index is -1, in AV_TIME_BASE units.
2121 * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
2122 * keyframes (this may not be supported by all demuxers).
2123 * If flags contain AVSEEK_FLAG_BACKWARD, it is ignored.
2124 *
2125 * @param s media file handle
2126 * @param stream_index index of the stream which is used as time base reference
2127 * @param min_ts smallest acceptable timestamp
2128 * @param ts target timestamp
2129 * @param max_ts largest acceptable timestamp
2130 * @param flags flags
2131 * @return >=0 on success, error code otherwise
2132 *
2133 * @note This is part of the new seek API which is still under construction.
2134 * Thus do not use this yet. It may change at any time, do not expect
2135 * ABI compatibility yet!
2136 */
2138
2139 /**
2140 * Discard all internally buffered data. This can be useful when dealing with
2141 * discontinuities in the byte stream. Generally works only with formats that
2142 * can resync. This includes headerless formats like MPEG-TS/TS but should also
2143 * work with NUT, Ogg and in a limited way AVI for example.
2144 *
2145 * The set of streams, the detected duration, stream parameters and codecs do
2146 * not change when calling this function. If you want a complete reset, it's
2147 * better to open a new AVFormatContext.
2148 *
2149 * This does not flush the AVIOContext (s->pb). If necessary, call
2150 * avio_flush(s->pb) before calling this function.
2151 *
2152 * @param s media file handle
2153 * @return >=0 on success, error code otherwise
2154 */
2156
2157 /**
2158 * Start playing a network-based stream (e.g. RTSP stream) at the
2159 * current position.
2160 */
2162
2163 /**
2164 * Pause a network-based stream (e.g. RTSP stream).
2165 *
2166 * Use av_read_play() to resume it.
2167 */
2169
2170 /**
2171 * Close an opened input AVFormatContext. Free it and all its contents
2172 * and set *s to NULL.
2173 */
2175 /**
2176 * @}
2177 */
2178
2179 #define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
2180 #define AVSEEK_FLAG_BYTE 2
///< seeking based on position in bytes
2181 #define AVSEEK_FLAG_ANY 4
///< seek to any frame, even non-keyframes
2182 #define AVSEEK_FLAG_FRAME 8
///< seeking based on frame number
2183
2184 /**
2185 * @addtogroup lavf_encoding
2186 * @{
2187 */
2188 /**
2189 * Allocate the stream private data and write the stream header to
2190 * an output media file.
2191 *
2192 * @param s Media file handle, must be allocated with avformat_alloc_context().
2193 * Its oformat field must be set to the desired output format;
2194 * Its pb field must be set to an already opened AVIOContext.
2195 * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
2196 * On return this parameter will be destroyed and replaced with a dict containing
2197 * options that were not found. May be NULL.
2198 *
2199 * @return 0 on success, negative AVERROR on failure.
2200 *
2201 * @see av_opt_find, av_dict_set, avio_open, av_oformat_next.
2202 */
2204
2205 /**
2206 * Write a packet to an output media file.
2207 *
2208 * This function passes the packet directly to the muxer, without any buffering
2209 * or reordering. The caller is responsible for correctly interleaving the
2210 * packets if the format requires it. Callers that want libavformat to handle
2211 * the interleaving should call av_interleaved_write_frame() instead of this
2212 * function.
2213 *
2214 * @param s media file handle
2215 * @param pkt The packet containing the data to be written. Note that unlike
2216 * av_interleaved_write_frame(), this function does not take
2217 * ownership of the packet passed to it (though some muxers may make
2218 * an internal reference to the input packet).
2219 * <br>
2220 * This parameter can be NULL (at any time, not just at the end), in
2221 * order to immediately flush data buffered within the muxer, for
2222 * muxers that buffer up data internally before writing it to the
2223 * output.
2224 * <br>
2225 * Packet's @ref AVPacket.stream_index "stream_index" field must be
2226 * set to the index of the corresponding stream in @ref
2227 * AVFormatContext.streams "s->streams". It is very strongly
2228 * recommended that timing information (@ref AVPacket.pts "pts", @ref
2229 * AVPacket.dts "dts", @ref AVPacket.duration "duration") is set to
2230 * correct values.
2231 * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
2232 *
2233 * @see av_interleaved_write_frame()
2234 */
2236
2237 /**
2238 * Write a packet to an output media file ensuring correct interleaving.
2239 *
2240 * This function will buffer the packets internally as needed to make sure the
2241 * packets in the output file are properly interleaved in the order of
2242 * increasing dts. Callers doing their own interleaving should call
2243 * av_write_frame() instead of this function.
2244 *
2245 * @param s media file handle
2246 * @param pkt The packet containing the data to be written.
2247 * <br>
2248 * If the packet is reference-counted, this function will take
2249 * ownership of this reference and unreference it later when it sees
2250 * fit.
2251 * The caller must not access the data through this reference after
2252 * this function returns. If the packet is not reference-counted,
2253 * libavformat will make a copy.
2254 * <br>
2255 * This parameter can be NULL (at any time, not just at the end), to
2256 * flush the interleaving queues.
2257 * <br>
2258 * Packet's @ref AVPacket.stream_index "stream_index" field must be
2259 * set to the index of the corresponding stream in @ref
2260 * AVFormatContext.streams "s->streams". It is very strongly
2261 * recommended that timing information (@ref AVPacket.pts "pts", @ref
2262 * AVPacket.dts "dts", @ref AVPacket.duration "duration") is set to
2263 * correct values.
2264 *
2265 * @return 0 on success, a negative AVERROR on error. Libavformat will always
2266 * take care of freeing the packet, even if this function fails.
2267 *
2268 * @see av_write_frame(), AVFormatContext.max_interleave_delta
2269 */
2271
2272 /**
2273 * Write a uncoded frame to an output media file.
2274 *
2275 * The frame must be correctly interleaved according to the container
2276 * specification; if not, then av_interleaved_write_frame() must be used.
2277 *
2278 * See av_interleaved_write_frame() for details.
2279 */
2282
2283 /**
2284 * Write a uncoded frame to an output media file.
2285 *
2286 * If the muxer supports it, this function allows to write an AVFrame
2287 * structure directly, without encoding it into a packet.
2288 * It is mostly useful for devices and similar special muxers that use raw
2289 * video or PCM data and will not serialize it into a byte stream.
2290 *
2291 * To test whether it is possible to use it with a given muxer and stream,
2292 * use av_write_uncoded_frame_query().
2293 *
2294 * The caller gives up ownership of the frame and must not access it
2295 * afterwards.
2296 *
2297 * @return >=0 for success, a negative code on error
2298 */
2301
2302 /**
2303 * Test whether a muxer supports uncoded frame.
2304 *
2305 * @return >=0 if an uncoded frame can be written to that muxer and stream,
2306 * <0 if not
2307 */
2309
2310 /**
2311 * Write the stream trailer to an output media file and free the
2312 * file private data.
2313 *
2314 * May only be called after a successful call to avformat_write_header.
2315 *
2316 * @param s media file handle
2317 * @return 0 if OK, AVERROR_xxx on error
2318 */
2320
2321 /**
2322 * Return the output format in the list of registered output formats
2323 * which best matches the provided parameters, or return NULL if
2324 * there is no match.
2325 *
2326 * @param short_name if non-NULL checks if short_name matches with the
2327 * names of the registered formats
2328 * @param filename if non-NULL checks if filename terminates with the
2329 * extensions of the registered formats
2330 * @param mime_type if non-NULL checks if mime_type matches with the
2331 * MIME type of the registered formats
2332 */
2334 const char *filename,
2335 const char *mime_type);
2336
2337 /**
2338 * Guess the codec ID based upon muxer and filename.
2339 */
2341 const char *filename, const char *mime_type,
2343
2344 /**
2345 * Get timing information for the data currently output.
2346 * The exact meaning of "currently output" depends on the format.
2347 * It is mostly relevant for devices that have an internal buffer and/or
2348 * work in real time.
2349 * @param s media file handle
2350 * @param stream stream in the media file
2351 * @param[out] dts DTS of the last packet output for the stream, in stream
2352 * time_base units
2353 * @param[out] wall absolute time when that packet whas output,
2354 * in microsecond
2355 * @return 0 if OK, AVERROR(ENOSYS) if the format does not support it
2356 * Note: some formats or devices may not allow to measure dts and wall
2357 * atomically.
2358 */
2360 int64_t *dts, int64_t *wall);
2361
2362
2363 /**
2364 * @}
2365 */
2366
2367
2368 /**
2369 * @defgroup lavf_misc Utility functions
2370 * @ingroup libavf
2371 * @{
2372 *
2373 * Miscellaneous utility functions related to both muxing and demuxing
2374 * (or neither).
2375 */
2376
2377 /**
2378 * Send a nice hexadecimal dump of a buffer to the specified file stream.
2379 *
2380 * @param f The file stream pointer where the dump should be sent to.
2381 * @param buf buffer
2382 * @param size buffer size
2383 *
2384 * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
2385 */
2387
2388 /**
2389 * Send a nice hexadecimal dump of a buffer to the log.
2390 *
2391 * @param avcl A pointer to an arbitrary struct of which the first field is a
2392 * pointer to an AVClass struct.
2393 * @param level The importance level of the message, lower values signifying
2394 * higher importance.
2395 * @param buf buffer
2396 * @param size buffer size
2397 *
2398 * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
2399 */
2401
2402 /**
2403 * Send a nice dump of a packet to the specified file stream.
2404 *
2405 * @param f The file stream pointer where the dump should be sent to.
2406 * @param pkt packet to dump
2407 * @param dump_payload True if the payload must be displayed, too.
2408 * @param st AVStream that the packet belongs to
2409 */
2411
2412
2413 /**
2414 * Send a nice dump of a packet to the log.
2415 *
2416 * @param avcl A pointer to an arbitrary struct of which the first field is a
2417 * pointer to an AVClass struct.
2418 * @param level The importance level of the message, lower values signifying
2419 * higher importance.
2420 * @param pkt packet to dump
2421 * @param dump_payload True if the payload must be displayed, too.
2422 * @param st AVStream that the packet belongs to
2423 */
2426
2427 /**
2428 * Get the AVCodecID for the given codec tag tag.
2429 * If no codec id is found returns AV_CODEC_ID_NONE.
2430 *
2431 * @param tags list of supported codec_id-codec_tag pairs, as stored
2432 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2433 * @param tag codec tag to match to a codec ID
2434 */
2436
2437 /**
2438 * Get the codec tag for the given codec id id.
2439 * If no codec tag is found returns 0.
2440 *
2441 * @param tags list of supported codec_id-codec_tag pairs, as stored
2442 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2443 * @param id codec ID to match to a codec tag
2444 */
2446
2447 /**
2448 * Get the codec tag for the given codec id.
2449 *
2450 * @param tags list of supported codec_id - codec_tag pairs, as stored
2451 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
2452 * @param id codec id that should be searched for in the list
2453 * @param tag A pointer to the found tag
2454 * @return 0 if id was not found in tags, > 0 if it was found
2455 */
2458
2460
2461 /**
2462 * Get the index for a specific timestamp.
2463 *
2464 * @param st stream that the timestamp belongs to
2465 * @param timestamp timestamp to retrieve the index for
2466 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
2467 * to the timestamp which is <= the requested one, if backward
2468 * is 0, then it will be >=
2469 * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
2470 * @return < 0 if no such timestamp could be found
2471 */
2473
2474 /**
2475 * Add an index entry into a sorted list. Update the entry if the list
2476 * already contains it.
2477 *
2478 * @param timestamp timestamp in the time base of the given stream
2479 */
2482
2483
2484 /**
2485 * Split a URL string into components.
2486 *
2487 * The pointers to buffers for storing individual components may be null,
2488 * in order to ignore that component. Buffers for components not found are
2489 * set to empty strings. If the port is not found, it is set to a negative
2490 * value.
2491 *
2492 * @param proto the buffer for the protocol
2493 * @param proto_size the size of the proto buffer
2494 * @param authorization the buffer for the authorization
2495 * @param authorization_size the size of the authorization buffer
2496 * @param hostname the buffer for the host name
2497 * @param hostname_size the size of the hostname buffer
2498 * @param port_ptr a pointer to store the port number in
2499 * @param path the buffer for the path
2500 * @param path_size the size of the path buffer
2501 * @param url the URL to split
2502 */
2504 char *authorization, int authorization_size,
2505 char *hostname, int hostname_size,
2506 int *port_ptr,
2507 char *path, int path_size,
2508 const char *url);
2509
2510
2511 /**
2512 * Print detailed information about the input or output format, such as
2513 * duration, bitrate, streams, container, programs, metadata, side data,
2514 * codec and time base.
2515 *
2516 * @param ic the context to analyze
2517 * @param index index of the stream to dump information about
2518 * @param url the URL to print, such as source or destination file
2519 * @param is_output Select whether the specified context is an input(0) or output(1)
2520 */
2523 const char *url,
2524 int is_output);
2525
2526 /**
2527 * Return in 'buf' the path with '%d' replaced by a number.
2528 *
2529 * Also handles the '%0nd' format where 'n' is the total number
2530 * of digits and '%%'.
2531 *
2532 * @param buf destination buffer
2533 * @param buf_size destination buffer size
2534 * @param path numbered sequence string
2535 * @param number frame number
2536 * @return 0 if OK, -1 on format error
2537 */
2539 const char *path, int number);
2540
2541 /**
2542 * Check whether filename actually is a numbered sequence generator.
2543 *
2544 * @param filename possible numbered sequence string
2545 * @return 1 if a valid numbered sequence string, 0 otherwise
2546 */
2548
2549 /**
2550 * Generate an SDP for an RTP session.
2551 *
2552 * Note, this overwrites the id values of AVStreams in the muxer contexts
2553 * for getting unique dynamic payload types.
2554 *
2555 * @param ac array of AVFormatContexts describing the RTP streams. If the
2556 * array is composed by only one context, such context can contain
2557 * multiple AVStreams (one AVStream per RTP stream). Otherwise,
2558 * all the contexts in the array (an AVCodecContext per RTP stream)
2559 * must contain only one AVStream.
2560 * @param n_files number of AVCodecContexts contained in ac
2561 * @param buf buffer where the SDP will be stored (must be allocated by
2562 * the caller)
2563 * @param size the size of the buffer
2564 * @return 0 if OK, AVERROR_xxx on error
2565 */
2567
2568 /**
2569 * Return a positive value if the given filename has one of the given
2570 * extensions, 0 otherwise.
2571 *
2572 * @param filename file name to check against the given extensions
2573 * @param extensions a comma-separated list of filename extensions
2574 */
2575 int av_match_ext(
const char *filename,
const char *extensions);
2576
2577 /**
2578 * Test if the given container can store a codec.
2579 *
2580 * @param ofmt container to check for compatibility
2581 * @param codec_id codec to potentially store in container
2582 * @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
2583 *
2584 * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
2585 * A negative number if this information is not available.
2586 */
2588 int std_compliance);
2589
2590 /**
2591 * @defgroup riff_fourcc RIFF FourCCs
2592 * @{
2593 * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
2594 * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
2595 * following code:
2596 * @code
2597 * uint32_t tag = MKTAG('H', '2', '6', '4');
2598 * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
2599 * enum AVCodecID id = av_codec_get_id(table, tag);
2600 * @endcode
2601 */
2602 /**
2603 * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
2604 */
2606 /**
2607 * @return the table mapping RIFF FourCCs for audio to AVCodecID.
2608 */
2610 /**
2611 * @return the table mapping MOV FourCCs for video to libavcodec AVCodecID.
2612 */
2614 /**
2615 * @return the table mapping MOV FourCCs for audio to AVCodecID.
2616 */
2618
2619 /**
2620 * @}
2621 */
2622
2623 /**
2624 * Guess the sample aspect ratio of a frame, based on both the stream and the
2625 * frame aspect ratio.
2626 *
2627 * Since the frame aspect ratio is set by the codec but the stream aspect ratio
2628 * is set by the demuxer, these two may not be equal. This function tries to
2629 * return the value that you should use if you would like to display the frame.
2630 *
2631 * Basic logic is to use the stream aspect ratio if it is set to something sane
2632 * otherwise use the frame aspect ratio. This way a container setting, which is
2633 * usually easy to modify can override the coded value in the frames.
2634 *
2635 * @param format the format context which the stream is part of
2636 * @param stream the stream which the frame is part of
2637 * @param frame the frame with the aspect ratio to be determined
2638 * @return the guessed (valid) sample_aspect_ratio, 0/1 if no idea
2639 */
2641
2642 /**
2643 * Guess the frame rate, based on both the container and codec information.
2644 *
2645 * @param ctx the format context which the stream is part of
2646 * @param stream the stream which the frame is part of
2647 * @param frame the frame for which the frame rate should be determined, may be NULL
2648 * @return the guessed (valid) frame rate, 0/1 if no idea
2649 */
2651
2652 /**
2653 * Check if the stream st contained in s is matched by the stream specifier
2654 * spec.
2655 *
2656 * See the "stream specifiers" chapter in the documentation for the syntax
2657 * of spec.
2658 *
2659 * @return >0 if st is matched by spec;
2660 * 0 if st is not matched by spec;
2661 * AVERROR code if spec is invalid
2662 *
2663 * @note A stream specifier can match several streams in the format.
2664 */
2666 const char *spec);
2667
2669
2670
2671 /**
2672 * @}
2673 */
2674
2675 #endif /* AVFORMAT_AVFORMAT_H */