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 libavformat 32 * I/O and Muxing/Demuxing Library 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). 40 * Unless you are absolutely sure you won't use libavformat's network 41 * capabilities, you should also call avformat_network_init(). 42 * 43 * A supported input format is described by an AVInputFormat struct, conversely 44 * an output format is described by AVOutputFormat. You can iterate over all 45 * input/output formats using the av_demuxer_iterate / av_muxer_iterate() functions. 46 * The protocols layer is not part of the public API, so you can only get the names 47 * of supported protocols with the avio_enum_protocols() function. 48 * 49 * Main lavf structure used for both muxing and demuxing is AVFormatContext, 50 * which exports all information about the file being read or written. As with 51 * most Libavformat structures, its size is not part of public ABI, so it cannot be 52 * allocated on stack or directly with av_malloc(). To create an 53 * AVFormatContext, use avformat_alloc_context() (some functions, like 54 * avformat_open_input() might do that for you). 55 * 56 * Most importantly an AVFormatContext contains: 57 * @li the @ref AVFormatContext.iformat "input" or @ref AVFormatContext.oformat 58 * "output" format. It is either autodetected or set by user for input; 59 * always set by user for output. 60 * @li an @ref AVFormatContext.streams "array" of AVStreams, which describe all 61 * elementary streams stored in the file. AVStreams are typically referred to 62 * using their index in this array. 63 * @li an @ref AVFormatContext.pb "I/O context". It is either opened by lavf or 64 * set by user for input, always set by user for output (unless you are dealing 65 * with an AVFMT_NOFILE format). 66 * 67 * @section lavf_options Passing options to (de)muxers 68 * It is possible to configure lavf muxers and demuxers using the @ref avoptions 69 * mechanism. Generic (format-independent) libavformat options are provided by 70 * AVFormatContext, they can be examined from a user program by calling 71 * av_opt_next() / av_opt_find() on an allocated AVFormatContext (or its AVClass 72 * from avformat_get_class()). Private (format-specific) options are provided by 73 * AVFormatContext.priv_data if and only if AVInputFormat.priv_class / 74 * AVOutputFormat.priv_class of the corresponding format struct is non-NULL. 75 * Further options may be provided by the @ref AVFormatContext.pb "I/O context", 76 * if its AVClass is non-NULL, and the protocols layer. See the discussion on 77 * nesting in @ref avoptions documentation to learn how to access those. 78 * 79 * @section urls 80 * URL strings in libavformat are made of a scheme/protocol, a ':', and a 81 * scheme specific string. URLs without a scheme and ':' used for local files 82 * are supported but deprecated. "file:" should be used for local files. 83 * 84 * It is important that the scheme string is not taken from untrusted 85 * sources without checks. 86 * 87 * Note that some schemes/protocols are quite powerful, allowing access to 88 * both local and remote files, parts of them, concatenations of them, local 89 * audio and video devices and so on. 90 * 91 * @{ 92 * 93 * @defgroup lavf_decoding Demuxing 94 * @{ 95 * Demuxers read a media file and split it into chunks of data (@em packets). A 96 * @ref AVPacket "packet" contains one or more encoded frames which belongs to a 97 * single elementary stream. In the lavf API this process is represented by the 98 * avformat_open_input() function for opening a file, av_read_frame() for 99 * reading a single packet and finally avformat_close_input(), which does the 100 * cleanup. 101 * 102 * @section lavf_decoding_open Opening a media file 103 * The minimum information required to open a file is its URL, which 104 * is passed to avformat_open_input(), as in the following code: 105 * @code 106 * const char *url = "file:in.mp3"; 107 * AVFormatContext *s = NULL; 108 * int ret = avformat_open_input(&s, url, NULL, NULL); 109 * if (ret < 0) 110 * abort(); 111 * @endcode 112 * The above code attempts to allocate an AVFormatContext, open the 113 * specified file (autodetecting the format) and read the header, exporting the 114 * information stored there into s. Some formats do not have a header or do not 115 * store enough information there, so it is recommended that you call the 116 * avformat_find_stream_info() function which tries to read and decode a few 117 * frames to find missing information. 118 * 119 * In some cases you might want to preallocate an AVFormatContext yourself with 120 * avformat_alloc_context() and do some tweaking on it before passing it to 121 * avformat_open_input(). One such case is when you want to use custom functions 122 * for reading input data instead of lavf internal I/O layer. 123 * To do that, create your own AVIOContext with avio_alloc_context(), passing 124 * your reading callbacks to it. Then set the @em pb field of your 125 * AVFormatContext to newly created AVIOContext. 126 * 127 * Since the format of the opened file is in general not known until after 128 * avformat_open_input() has returned, it is not possible to set demuxer private 129 * options on a preallocated context. Instead, the options should be passed to 130 * avformat_open_input() wrapped in an AVDictionary: 131 * @code 132 * AVDictionary *options = NULL; 133 * av_dict_set(&options, "video_size", "640x480", 0); 134 * av_dict_set(&options, "pixel_format", "rgb24", 0); 135 * 136 * if (avformat_open_input(&s, url, NULL, &options) < 0) 137 * abort(); 138 * av_dict_free(&options); 139 * @endcode 140 * This code passes the private options 'video_size' and 'pixel_format' to the 141 * demuxer. They would be necessary for e.g. the rawvideo demuxer, since it 142 * cannot know how to interpret raw video data otherwise. If the format turns 143 * out to be something different than raw video, those options will not be 144 * recognized by the demuxer and therefore will not be applied. Such unrecognized 145 * options are then returned in the options dictionary (recognized options are 146 * consumed). The calling program can handle such unrecognized options as it 147 * wishes, e.g. 148 * @code 149 * AVDictionaryEntry *e; 150 * if (e = av_dict_get(options, "", NULL, AV_DICT_IGNORE_SUFFIX)) { 151 * fprintf(stderr, "Option %s not recognized by the demuxer.\n", e->key); 152 * abort(); 153 * } 154 * @endcode 155 * 156 * After you have finished reading the file, you must close it with 157 * avformat_close_input(). It will free everything associated with the file. 158 * 159 * @section lavf_decoding_read Reading from an opened file 160 * Reading data from an opened AVFormatContext is done by repeatedly calling 161 * av_read_frame() on it. Each call, if successful, will return an AVPacket 162 * containing encoded data for one AVStream, identified by 163 * AVPacket.stream_index. This packet may be passed straight into the libavcodec 164 * decoding functions avcodec_send_packet() or avcodec_decode_subtitle2() if the 165 * caller wishes to decode the data. 166 * 167 * AVPacket.pts, AVPacket.dts and AVPacket.duration timing information will be 168 * set if known. They may also be unset (i.e. AV_NOPTS_VALUE for 169 * pts/dts, 0 for duration) if the stream does not provide them. The timing 170 * information will be in AVStream.time_base units, i.e. it has to be 171 * multiplied by the timebase to convert them to seconds. 172 * 173 * A packet returned by av_read_frame() is always reference-counted, 174 * i.e. AVPacket.buf is set and the user may keep it indefinitely. 175 * The packet must be freed with av_packet_unref() when it is no 176 * longer needed. 177 * 178 * @section lavf_decoding_seek Seeking 179 * @} 180 * 181 * @defgroup lavf_encoding Muxing 182 * @{ 183 * Muxers take encoded data in the form of @ref AVPacket "AVPackets" and write 184 * it into files or other output bytestreams in the specified container format. 185 * 186 * The main API functions for muxing are avformat_write_header() for writing the 187 * file header, av_write_frame() / av_interleaved_write_frame() for writing the 188 * packets and av_write_trailer() for finalizing the file. 189 * 190 * At the beginning of the muxing process, the caller must first call 191 * avformat_alloc_context() to create a muxing context. The caller then sets up 192 * the muxer by filling the various fields in this context: 193 * 194 * - The @ref AVFormatContext.oformat "oformat" field must be set to select the 195 * muxer that will be used. 196 * - Unless the format is of the AVFMT_NOFILE type, the @ref AVFormatContext.pb 197 * "pb" field must be set to an opened IO context, either returned from 198 * avio_open2() or a custom one. 199 * - Unless the format is of the AVFMT_NOSTREAMS type, at least one stream must 200 * be created with the avformat_new_stream() function. The caller should fill 201 * the @ref AVStream.codecpar "stream codec parameters" information, such as the 202 * codec @ref AVCodecParameters.codec_type "type", @ref AVCodecParameters.codec_id 203 * "id" and other parameters (e.g. width / height, the pixel or sample format, 204 * etc.) as known. The @ref AVStream.time_base "stream timebase" should 205 * be set to the timebase that the caller desires to use for this stream (note 206 * that the timebase actually used by the muxer can be different, as will be 207 * described later). 208 * - It is advised to manually initialize only the relevant fields in 209 * AVCodecParameters, rather than using @ref avcodec_parameters_copy() during 210 * remuxing: there is no guarantee that the codec context values remain valid 211 * for both input and output format contexts. 212 * - The caller may fill in additional information, such as @ref 213 * AVFormatContext.metadata "global" or @ref AVStream.metadata "per-stream" 214 * metadata, @ref AVFormatContext.chapters "chapters", @ref 215 * AVFormatContext.programs "programs", etc. as described in the 216 * AVFormatContext documentation. Whether such information will actually be 217 * stored in the output depends on what the container format and the muxer 218 * support. 219 * 220 * When the muxing context is fully set up, the caller must call 221 * avformat_write_header() to initialize the muxer internals and write the file 222 * header. Whether anything actually is written to the IO context at this step 223 * depends on the muxer, but this function must always be called. Any muxer 224 * private options must be passed in the options parameter to this function. 225 * 226 * The data is then sent to the muxer by repeatedly calling av_write_frame() or 227 * av_interleaved_write_frame() (consult those functions' documentation for 228 * discussion on the difference between them; only one of them may be used with 229 * a single muxing context, they should not be mixed). Do note that the timing 230 * information on the packets sent to the muxer must be in the corresponding 231 * AVStream's timebase. That timebase is set by the muxer (in the 232 * avformat_write_header() step) and may be different from the timebase 233 * requested by the caller. 234 * 235 * Once all the data has been written, the caller must call av_write_trailer() 236 * to flush any buffered packets and finalize the output file, then close the IO 237 * context (if any) and finally free the muxing context with 238 * avformat_free_context(). 239 * @} 240 * 241 * @defgroup lavf_io I/O Read/Write 242 * @{ 243 * @section lavf_io_dirlist Directory listing 244 * The directory listing API makes it possible to list files on remote servers. 245 * 246 * Some of possible use cases: 247 * - an "open file" dialog to choose files from a remote location, 248 * - a recursive media finder providing a player with an ability to play all 249 * files from a given directory. 250 * 251 * @subsection lavf_io_dirlist_open Opening a directory 252 * At first, a directory needs to be opened by calling avio_open_dir() 253 * supplied with a URL and, optionally, ::AVDictionary containing 254 * protocol-specific parameters. The function returns zero or positive 255 * integer and allocates AVIODirContext on success. 256 * 257 * @code 258 * AVIODirContext *ctx = NULL; 259 * if (avio_open_dir(&ctx, "smb://example.com/some_dir", NULL) < 0) { 260 * fprintf(stderr, "Cannot open directory.\n"); 261 * abort(); 262 * } 263 * @endcode 264 * 265 * This code tries to open a sample directory using smb protocol without 266 * any additional parameters. 267 * 268 * @subsection lavf_io_dirlist_read Reading entries 269 * Each directory's entry (i.e. file, another directory, anything else 270 * within ::AVIODirEntryType) is represented by AVIODirEntry. 271 * Reading consecutive entries from an opened AVIODirContext is done by 272 * repeatedly calling avio_read_dir() on it. Each call returns zero or 273 * positive integer if successful. Reading can be stopped right after the 274 * NULL entry has been read -- it means there are no entries left to be 275 * read. The following code reads all entries from a directory associated 276 * with ctx and prints their names to standard output. 277 * @code 278 * AVIODirEntry *entry = NULL; 279 * for (;;) { 280 * if (avio_read_dir(ctx, &entry) < 0) { 281 * fprintf(stderr, "Cannot list directory.\n"); 282 * abort(); 283 * } 284 * if (!entry) 285 * break; 286 * printf("%s\n", entry->name); 287 * avio_free_directory_entry(&entry); 288 * } 289 * @endcode 290 * @} 291 * 292 * @defgroup lavf_codec Demuxers 293 * @{ 294 * @defgroup lavf_codec_native Native Demuxers 295 * @{ 296 * @} 297 * @defgroup lavf_codec_wrappers External library wrappers 298 * @{ 299 * @} 300 * @} 301 * @defgroup lavf_protos I/O Protocols 302 * @{ 303 * @} 304 * @defgroup lavf_internal Internal 305 * @{ 306 * @} 307 * @} 308 */ 309 310 #include <time.h> 311 #include <stdio.h> /* FILE */ 312 313 #include "libavcodec/codec.h" 314 #include "libavcodec/codec_par.h" 315 #include "libavcodec/defs.h" 316 #include "libavcodec/packet.h" 317 318 #include "libavutil/dict.h" 319 #include "libavutil/log.h" 320 321 #include "avio.h" 322 #include "libavformat/version_major.h" 323 #ifndef HAVE_AV_CONFIG_H 324 /* When included as part of the ffmpeg build, only include the major version 325 * to avoid unnecessary rebuilds. When included externally, keep including 326 * the full version information. */ 327 #include "libavformat/version.h" 328 #endif 329 330 struct AVFormatContext; 331 struct AVStream; 332 333 struct AVDeviceInfoList; 334 struct AVDeviceCapabilitiesQuery; 335 336 /** 337 * @defgroup metadata_api Public Metadata API 338 * @{ 339 * @ingroup libavf 340 * The metadata API allows libavformat to export metadata tags to a client 341 * application when demuxing. Conversely it allows a client application to 342 * set metadata when muxing. 343 * 344 * Metadata is exported or set as pairs of key/value strings in the 'metadata' 345 * fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs 346 * using the @ref lavu_dict "AVDictionary" API. Like all strings in FFmpeg, 347 * metadata is assumed to be UTF-8 encoded Unicode. Note that metadata 348 * exported by demuxers isn't checked to be valid UTF-8 in most cases. 349 * 350 * Important concepts to keep in mind: 351 * - Keys are unique; there can never be 2 tags with the same key. This is 352 * also meant semantically, i.e., a demuxer should not knowingly produce 353 * several keys that are literally different but semantically identical. 354 * E.g., key=Author5, key=Author6. In this example, all authors must be 355 * placed in the same tag. 356 * - Metadata is flat, not hierarchical; there are no subtags. If you 357 * want to store, e.g., the email address of the child of producer Alice 358 * and actor Bob, that could have key=alice_and_bobs_childs_email_address. 359 * - Several modifiers can be applied to the tag name. This is done by 360 * appending a dash character ('-') and the modifier name in the order 361 * they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng. 362 * - language -- a tag whose value is localized for a particular language 363 * is appended with the ISO 639-2/B 3-letter language code. 364 * For example: Author-ger=Michael, Author-eng=Mike 365 * The original/default language is in the unqualified "Author" tag. 366 * A demuxer should set a default if it sets any translated tag. 367 * - sorting -- a modified version of a tag that should be used for 368 * sorting will have '-sort' appended. E.g. artist="The Beatles", 369 * artist-sort="Beatles, The". 370 * - Some protocols and demuxers support metadata updates. After a successful 371 * call to av_read_frame(), AVFormatContext.event_flags or AVStream.event_flags 372 * will be updated to indicate if metadata changed. In order to detect metadata 373 * changes on a stream, you need to loop through all streams in the AVFormatContext 374 * and check their individual event_flags. 375 * 376 * - Demuxers attempt to export metadata in a generic format, however tags 377 * with no generic equivalents are left as they are stored in the container. 378 * Follows a list of generic tag names: 379 * 380 @verbatim 381 album -- name of the set this work belongs to 382 album_artist -- main creator of the set/album, if different from artist. 383 e.g. "Various Artists" for compilation albums. 384 artist -- main creator of the work 385 comment -- any additional description of the file. 386 composer -- who composed the work, if different from artist. 387 copyright -- name of copyright holder. 388 creation_time-- date when the file was created, preferably in ISO 8601. 389 date -- date when the work was created, preferably in ISO 8601. 390 disc -- number of a subset, e.g. disc in a multi-disc collection. 391 encoder -- name/settings of the software/hardware that produced the file. 392 encoded_by -- person/group who created the file. 393 filename -- original name of the file. 394 genre -- <self-evident>. 395 language -- main language in which the work is performed, preferably 396 in ISO 639-2 format. Multiple languages can be specified by 397 separating them with commas. 398 performer -- artist who performed the work, if different from artist. 399 E.g for "Also sprach Zarathustra", artist would be "Richard 400 Strauss" and performer "London Philharmonic Orchestra". 401 publisher -- name of the label/publisher. 402 service_name -- name of the service in broadcasting (channel name). 403 service_provider -- name of the service provider in broadcasting. 404 title -- name of the work. 405 track -- number of this work in the set, can be in form current/total. 406 variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of 407 @endverbatim 408 * 409 * Look in the examples section for an application example how to use the Metadata API. 410 * 411 * @} 412 */ 413 414 /* packet functions */ 415 416 417 /** 418 * Allocate and read the payload of a packet and initialize its 419 * fields with default values. 420 * 421 * @param s associated IO context 422 * @param pkt packet 423 * @param size desired payload size 424 * @return >0 (read size) if OK, AVERROR_xxx otherwise 425 */ 426 int av_get_packet(AVIOContext *s, AVPacket *pkt, int size); 427 428 429 /** 430 * Read data and append it to the current content of the AVPacket. 431 * If pkt->size is 0 this is identical to av_get_packet. 432 * Note that this uses av_grow_packet and thus involves a realloc 433 * which is inefficient. Thus this function should only be used 434 * when there is no reasonable way to know (an upper bound of) 435 * the final size. 436 * 437 * @param s associated IO context 438 * @param pkt packet 439 * @param size amount of data to read 440 * @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data 441 * will not be lost even if an error occurs. 442 */ 443 int av_append_packet(AVIOContext *s, AVPacket *pkt, int size); 444 445 /*************************************************/ 446 /* input/output formats */ 447 448 struct AVCodecTag; 449 450 /** 451 * This structure contains the data a format has to probe a file. 452 */ 453 typedef struct AVProbeData { 454 const char *filename; 455 unsigned char *buf; /**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */ 456 int buf_size; /**< Size of buf except extra allocated bytes */ 457 const char *mime_type; /**< mime_type, when known. */ 458 } AVProbeData; 459 460 #define AVPROBE_SCORE_RETRY (AVPROBE_SCORE_MAX/4) 461 #define AVPROBE_SCORE_STREAM_RETRY (AVPROBE_SCORE_MAX/4-1) 462 463 #define AVPROBE_SCORE_EXTENSION 50 ///< score for file extension 464 #define AVPROBE_SCORE_MIME 75 ///< score for file mime type 465 #define AVPROBE_SCORE_MAX 100 ///< maximum score 466 467 #define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer 468 469 /// Demuxer will use avio_open, no opened file should be provided by the caller. 470 #define AVFMT_NOFILE 0x0001 471 #define AVFMT_NEEDNUMBER 0x0002 /**< Needs '%d' in filename. */ 472 /** 473 * The muxer/demuxer is experimental and should be used with caution. 474 * 475 * - demuxers: will not be selected automatically by probing, must be specified 476 * explicitly. 477 */ 478 #define AVFMT_EXPERIMENTAL 0x0004 479 #define AVFMT_SHOW_IDS 0x0008 /**< Show format stream IDs numbers. */ 480 #define AVFMT_GLOBALHEADER 0x0040 /**< Format wants global header. */ 481 #define AVFMT_NOTIMESTAMPS 0x0080 /**< Format does not need / have any timestamps. */ 482 #define AVFMT_GENERIC_INDEX 0x0100 /**< Use generic index building code. */ 483 #define AVFMT_TS_DISCONT 0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */ 484 #define AVFMT_VARIABLE_FPS 0x0400 /**< Format allows variable fps. */ 485 #define AVFMT_NODIMENSIONS 0x0800 /**< Format does not need width/height */ 486 #define AVFMT_NOSTREAMS 0x1000 /**< Format does not require any streams */ 487 #define AVFMT_NOBINSEARCH 0x2000 /**< Format does not allow to fall back on binary search via read_timestamp */ 488 #define AVFMT_NOGENSEARCH 0x4000 /**< Format does not allow to fall back on generic search */ 489 #define AVFMT_NO_BYTE_SEEK 0x8000 /**< Format does not allow seeking by bytes */ 490 #define AVFMT_ALLOW_FLUSH 0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */ 491 #define AVFMT_TS_NONSTRICT 0x20000 /**< Format does not require strictly 492 increasing timestamps, but they must 493 still be monotonic */ 494 #define AVFMT_TS_NEGATIVE 0x40000 /**< Format allows muxing negative 495 timestamps. If not set the timestamp 496 will be shifted in av_write_frame and 497 av_interleaved_write_frame so they 498 start from 0. 499 The user or muxer can override this through 500 AVFormatContext.avoid_negative_ts 501 */ 502 503 #define AVFMT_SEEK_TO_PTS 0x4000000 /**< Seeking is based on PTS */ 504 505 /** 506 * @addtogroup lavf_encoding 507 * @{ 508 */ 509 typedef struct AVOutputFormat { 510 const char *name; 511 /** 512 * Descriptive name for the format, meant to be more human-readable 513 * than name. You should use the NULL_IF_CONFIG_SMALL() macro 514 * to define it. 515 */ 516 const char *long_name; 517 const char *mime_type; 518 const char *extensions; /**< comma-separated filename extensions */ 519 /* output support */ 520 enum AVCodecID audio_codec; /**< default audio codec */ 521 enum AVCodecID video_codec; /**< default video codec */ 522 enum AVCodecID subtitle_codec; /**< default subtitle codec */ 523 /** 524 * can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, 525 * AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS, 526 * AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH, 527 * AVFMT_TS_NONSTRICT, AVFMT_TS_NEGATIVE 528 */ 529 int flags; 530 531 /** 532 * List of supported codec_id-codec_tag pairs, ordered by "better 533 * choice first". The arrays are all terminated by AV_CODEC_ID_NONE. 534 */ 535 const struct AVCodecTag * const *codec_tag; 536 537 538 const AVClass *priv_class; ///< AVClass for the private context 539 540 /***************************************************************** 541 * No fields below this line are part of the public API. They 542 * may not be used outside of libavformat and can be changed and 543 * removed at will. 544 * New public fields should be added right above. 545 ***************************************************************** 546 */ 547 /** 548 * size of private data so that it can be allocated in the wrapper 549 */ 550 int priv_data_size; 551 552 /** 553 * Internal flags. See FF_FMT_FLAG_* in internal.h. 554 */ 555 int flags_internal; 556 557 int (*write_header)(struct AVFormatContext *); 558 /** 559 * Write a packet. If AVFMT_ALLOW_FLUSH is set in flags, 560 * pkt can be NULL in order to flush data buffered in the muxer. 561 * When flushing, return 0 if there still is more data to flush, 562 * or 1 if everything was flushed and there is no more buffered 563 * data. 564 */ 565 int (*write_packet)(struct AVFormatContext *, AVPacket *pkt); 566 int (*write_trailer)(struct AVFormatContext *); 567 /** 568 * A format-specific function for interleavement. 569 * If unset, packets will be interleaved by dts. 570 * 571 * @param s An AVFormatContext for output. pkt will be added to 572 * resp. taken from its packet buffer. 573 * @param[in,out] pkt A packet to be interleaved if has_packet is set; 574 * also used to return packets. If no packet is returned 575 * (e.g. on error), pkt is blank on return. 576 * @param flush 1 if no further packets are available as input and 577 * all remaining packets should be output. 578 * @param has_packet If set, pkt contains a packet to be interleaved 579 * on input; otherwise pkt is blank on input. 580 * @return 1 if a packet was output, 0 if no packet could be output, 581 * < 0 if an error occurred 582 */ 583 int (*interleave_packet)(struct AVFormatContext *s, AVPacket *pkt, 584 int flush, int has_packet); 585 /** 586 * Test if the given codec can be stored in this container. 587 * 588 * @return 1 if the codec is supported, 0 if it is not. 589 * A negative number if unknown. 590 * MKTAG('A', 'P', 'I', 'C') if the codec is only supported as AV_DISPOSITION_ATTACHED_PIC 591 */ 592 int (*query_codec)(enum AVCodecID id, int std_compliance); 593 594 void (*get_output_timestamp)(struct AVFormatContext *s, int stream, 595 int64_t *dts, int64_t *wall); 596 /** 597 * Allows sending messages from application to device. 598 */ 599 int (*control_message)(struct AVFormatContext *s, int type, 600 void *data, size_t data_size); 601 602 /** 603 * Write an uncoded AVFrame. 604 * 605 * See av_write_uncoded_frame() for details. 606 * 607 * The library will free *frame afterwards, but the muxer can prevent it 608 * by setting the pointer to NULL. 609 */ 610 int (*write_uncoded_frame)(struct AVFormatContext *, int stream_index, 611 AVFrame **frame, unsigned flags); 612 /** 613 * Returns device list with it properties. 614 * @see avdevice_list_devices() for more details. 615 */ 616 int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list); 617 enum AVCodecID data_codec; /**< default data codec */ 618 /** 619 * Initialize format. May allocate data here, and set any AVFormatContext or 620 * AVStream parameters that need to be set before packets are sent. 621 * This method must not write output. 622 * 623 * Return 0 if streams were fully configured, 1 if not, negative AVERROR on failure 624 * 625 * Any allocations made here must be freed in deinit(). 626 */ 627 int (*init)(struct AVFormatContext *); 628 /** 629 * Deinitialize format. If present, this is called whenever the muxer is being 630 * destroyed, regardless of whether or not the header has been written. 631 * 632 * If a trailer is being written, this is called after write_trailer(). 633 * 634 * This is called if init() fails as well. 635 */ 636 void (*deinit)(struct AVFormatContext *); 637 /** 638 * Set up any necessary bitstream filtering and extract any extra data needed 639 * for the global header. 640 * 641 * @note pkt might have been directly forwarded by a meta-muxer; therefore 642 * pkt->stream_index as well as the pkt's timebase might be invalid. 643 * Return 0 if more packets from this stream must be checked; 1 if not. 644 */ 645 int (*check_bitstream)(struct AVFormatContext *s, struct AVStream *st, 646 const AVPacket *pkt); 647 } AVOutputFormat; 648 /** 649 * @} 650 */ 651 652 /** 653 * @addtogroup lavf_decoding 654 * @{ 655 */ 656 typedef struct AVInputFormat { 657 /** 658 * A comma separated list of short names for the format. New names 659 * may be appended with a minor bump. 660 */ 661 const char *name; 662 663 /** 664 * Descriptive name for the format, meant to be more human-readable 665 * than name. You should use the NULL_IF_CONFIG_SMALL() macro 666 * to define it. 667 */ 668 const char *long_name; 669 670 /** 671 * Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS, 672 * AVFMT_NOTIMESTAMPS, AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH, 673 * AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK, AVFMT_SEEK_TO_PTS. 674 */ 675 int flags; 676 677 /** 678 * If extensions are defined, then no probe is done. You should 679 * usually not use extension format guessing because it is not 680 * reliable enough 681 */ 682 const char *extensions; 683 684 const struct AVCodecTag * const *codec_tag; 685 686 const AVClass *priv_class; ///< AVClass for the private context 687 688 /** 689 * Comma-separated list of mime types. 690 * It is used check for matching mime types while probing. 691 * @see av_probe_input_format2 692 */ 693 const char *mime_type; 694 695 /***************************************************************** 696 * No fields below this line are part of the public API. They 697 * may not be used outside of libavformat and can be changed and 698 * removed at will. 699 * New public fields should be added right above. 700 ***************************************************************** 701 */ 702 /** 703 * Raw demuxers store their codec ID here. 704 */ 705 int raw_codec_id; 706 707 /** 708 * Size of private data so that it can be allocated in the wrapper. 709 */ 710 int priv_data_size; 711 712 /** 713 * Internal flags. See FF_FMT_FLAG_* in internal.h. 714 */ 715 int flags_internal; 716 717 /** 718 * Tell if a given file has a chance of being parsed as this format. 719 * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes 720 * big so you do not have to check for that unless you need more. 721 */ 722 int (*read_probe)(const AVProbeData *); 723 724 /** 725 * Read the format header and initialize the AVFormatContext 726 * structure. Return 0 if OK. 'avformat_new_stream' should be 727 * called to create new streams. 728 */ 729 int (*read_header)(struct AVFormatContext *); 730 731 /** 732 * Read one packet and put it in 'pkt'. pts and flags are also 733 * set. 'avformat_new_stream' can be called only if the flag 734 * AVFMTCTX_NOHEADER is used and only in the calling thread (not in a 735 * background thread). 736 * @return 0 on success, < 0 on error. 737 * Upon returning an error, pkt must be unreferenced by the caller. 738 */ 739 int (*read_packet)(struct AVFormatContext *, AVPacket *pkt); 740 741 /** 742 * Close the stream. The AVFormatContext and AVStreams are not 743 * freed by this function 744 */ 745 int (*read_close)(struct AVFormatContext *); 746 747 /** 748 * Seek to a given timestamp relative to the frames in 749 * stream component stream_index. 750 * @param stream_index Must not be -1. 751 * @param flags Selects which direction should be preferred if no exact 752 * match is available. 753 * @return >= 0 on success (but not necessarily the new offset) 754 */ 755 int (*read_seek)(struct AVFormatContext *, 756 int stream_index, int64_t timestamp, int flags); 757 758 /** 759 * Get the next timestamp in stream[stream_index].time_base units. 760 * @return the timestamp or AV_NOPTS_VALUE if an error occurred 761 */ 762 int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index, 763 int64_t *pos, int64_t pos_limit); 764 765 /** 766 * Start/resume playing - only meaningful if using a network-based format 767 * (RTSP). 768 */ 769 int (*read_play)(struct AVFormatContext *); 770 771 /** 772 * Pause playing - only meaningful if using a network-based format 773 * (RTSP). 774 */ 775 int (*read_pause)(struct AVFormatContext *); 776 777 /** 778 * Seek to timestamp ts. 779 * Seeking will be done so that the point from which all active streams 780 * can be presented successfully will be closest to ts and within min/max_ts. 781 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL. 782 */ 783 int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags); 784 785 /** 786 * Returns device list with it properties. 787 * @see avdevice_list_devices() for more details. 788 */ 789 int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list); 790 791 } AVInputFormat; 792 /** 793 * @} 794 */ 795 796 enum AVStreamParseType { 797 AVSTREAM_PARSE_NONE, 798 AVSTREAM_PARSE_FULL, /**< full parsing and repack */ 799 AVSTREAM_PARSE_HEADERS, /**< Only parse headers, do not repack. */ 800 AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */ 801 AVSTREAM_PARSE_FULL_ONCE, /**< full parsing and repack of the first frame only, only implemented for H.264 currently */ 802 AVSTREAM_PARSE_FULL_RAW, /**< full parsing and repack with timestamp and position generation by parser for raw 803 this assumes that each packet in the file contains no demuxer level headers and 804 just codec level data, otherwise position generation would fail */ 805 }; 806 807 typedef struct AVIndexEntry { 808 int64_t pos; 809 int64_t timestamp; /**< 810 * Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are available 811 * when seeking to this entry. That means preferable PTS on keyframe based formats. 812 * But demuxers can choose to store a different timestamp, if it is more convenient for the implementation or nothing better 813 * is known 814 */ 815 #define AVINDEX_KEYFRAME 0x0001 816 #define AVINDEX_DISCARD_FRAME 0x0002 /** 817 * Flag is used to indicate which frame should be discarded after decoding. 818 */ 819 int flags:2; 820 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). 821 int min_distance; /**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */ 822 } AVIndexEntry; 823 824 /** 825 * The stream should be chosen by default among other streams of the same type, 826 * unless the user has explicitly specified otherwise. 827 */ 828 #define AV_DISPOSITION_DEFAULT (1 << 0) 829 /** 830 * The stream is not in original language. 831 * 832 * @note AV_DISPOSITION_ORIGINAL is the inverse of this disposition. At most 833 * one of them should be set in properly tagged streams. 834 * @note This disposition may apply to any stream type, not just audio. 835 */ 836 #define AV_DISPOSITION_DUB (1 << 1) 837 /** 838 * The stream is in original language. 839 * 840 * @see the notes for AV_DISPOSITION_DUB 841 */ 842 #define AV_DISPOSITION_ORIGINAL (1 << 2) 843 /** 844 * The stream is a commentary track. 845 */ 846 #define AV_DISPOSITION_COMMENT (1 << 3) 847 /** 848 * The stream contains song lyrics. 849 */ 850 #define AV_DISPOSITION_LYRICS (1 << 4) 851 /** 852 * The stream contains karaoke audio. 853 */ 854 #define AV_DISPOSITION_KARAOKE (1 << 5) 855 856 /** 857 * Track should be used during playback by default. 858 * Useful for subtitle track that should be displayed 859 * even when user did not explicitly ask for subtitles. 860 */ 861 #define AV_DISPOSITION_FORCED (1 << 6) 862 /** 863 * The stream is intended for hearing impaired audiences. 864 */ 865 #define AV_DISPOSITION_HEARING_IMPAIRED (1 << 7) 866 /** 867 * The stream is intended for visually impaired audiences. 868 */ 869 #define AV_DISPOSITION_VISUAL_IMPAIRED (1 << 8) 870 /** 871 * The audio stream contains music and sound effects without voice. 872 */ 873 #define AV_DISPOSITION_CLEAN_EFFECTS (1 << 9) 874 /** 875 * The stream is stored in the file as an attached picture/"cover art" (e.g. 876 * APIC frame in ID3v2). The first (usually only) packet associated with it 877 * will be returned among the first few packets read from the file unless 878 * seeking takes place. It can also be accessed at any time in 879 * AVStream.attached_pic. 880 */ 881 #define AV_DISPOSITION_ATTACHED_PIC (1 << 10) 882 /** 883 * The stream is sparse, and contains thumbnail images, often corresponding 884 * to chapter markers. Only ever used with AV_DISPOSITION_ATTACHED_PIC. 885 */ 886 #define AV_DISPOSITION_TIMED_THUMBNAILS (1 << 11) 887 888 /** 889 * The stream is intended to be mixed with a spatial audio track. For example, 890 * it could be used for narration or stereo music, and may remain unchanged by 891 * listener head rotation. 892 */ 893 #define AV_DISPOSITION_NON_DIEGETIC (1 << 12) 894 895 /** 896 * The subtitle stream contains captions, providing a transcription and possibly 897 * a translation of audio. Typically intended for hearing-impaired audiences. 898 */ 899 #define AV_DISPOSITION_CAPTIONS (1 << 16) 900 /** 901 * The subtitle stream contains a textual description of the video content. 902 * Typically intended for visually-impaired audiences or for the cases where the 903 * video cannot be seen. 904 */ 905 #define AV_DISPOSITION_DESCRIPTIONS (1 << 17) 906 /** 907 * The subtitle stream contains time-aligned metadata that is not intended to be 908 * directly presented to the user. 909 */ 910 #define AV_DISPOSITION_METADATA (1 << 18) 911 /** 912 * The audio stream is intended to be mixed with another stream before 913 * presentation. 914 * Corresponds to mix_type=0 in mpegts. 915 */ 916 #define AV_DISPOSITION_DEPENDENT (1 << 19) 917 /** 918 * The video stream contains still images. 919 */ 920 #define AV_DISPOSITION_STILL_IMAGE (1 << 20) 921 922 /** 923 * @return The AV_DISPOSITION_* flag corresponding to disp or a negative error 924 * code if disp does not correspond to a known stream disposition. 925 */ 926 int av_disposition_from_string(const char *disp); 927 928 /** 929 * @param disposition a combination of AV_DISPOSITION_* values 930 * @return The string description corresponding to the lowest set bit in 931 * disposition. NULL when the lowest set bit does not correspond 932 * to a known disposition or when disposition is 0. 933 */ 934 const char *av_disposition_to_string(int disposition); 935 936 /** 937 * Options for behavior on timestamp wrap detection. 938 */ 939 #define AV_PTS_WRAP_IGNORE 0 ///< ignore the wrap 940 #define AV_PTS_WRAP_ADD_OFFSET 1 ///< add the format specific offset on wrap detection 941 #define AV_PTS_WRAP_SUB_OFFSET -1 ///< subtract the format specific offset on wrap detection 942 943 /** 944 * Stream structure. 945 * New fields can be added to the end with minor version bumps. 946 * Removal, reordering and changes to existing fields require a major 947 * version bump. 948 * sizeof(AVStream) must not be used outside libav*. 949 */ 950 typedef struct AVStream { 951 #if FF_API_AVSTREAM_CLASS 952 /** 953 * A class for @ref avoptions. Set on stream creation. 954 */ 955 const AVClass *av_class; 956 #endif 957 958 int index; /**< stream index in AVFormatContext */ 959 /** 960 * Format-specific stream ID. 961 * decoding: set by libavformat 962 * encoding: set by the user, replaced by libavformat if left unset 963 */ 964 int id; 965 966 void *priv_data; 967 968 /** 969 * This is the fundamental unit of time (in seconds) in terms 970 * of which frame timestamps are represented. 971 * 972 * decoding: set by libavformat 973 * encoding: May be set by the caller before avformat_write_header() to 974 * provide a hint to the muxer about the desired timebase. In 975 * avformat_write_header(), the muxer will overwrite this field 976 * with the timebase that will actually be used for the timestamps 977 * written into the file (which may or may not be related to the 978 * user-provided one, depending on the format). 979 */ 980 AVRational time_base; 981 982 /** 983 * Decoding: pts of the first frame of the stream in presentation order, in stream time base. 984 * Only set this if you are absolutely 100% sure that the value you set 985 * it to really is the pts of the first frame. 986 * This may be undefined (AV_NOPTS_VALUE). 987 * @note The ASF header does NOT contain a correct start_time the ASF 988 * demuxer must NOT set this. 989 */ 990 int64_t start_time; 991 992 /** 993 * Decoding: duration of the stream, in stream time base. 994 * If a source file does not specify a duration, but does specify 995 * a bitrate, this value will be estimated from bitrate and file size. 996 * 997 * Encoding: May be set by the caller before avformat_write_header() to 998 * provide a hint to the muxer about the estimated duration. 999 */ 1000 int64_t duration; 1001 1002 int64_t nb_frames; ///< number of frames in this stream if known or 0 1003 1004 /** 1005 * Stream disposition - a combination of AV_DISPOSITION_* flags. 1006 * - demuxing: set by libavformat when creating the stream or in 1007 * avformat_find_stream_info(). 1008 * - muxing: may be set by the caller before avformat_write_header(). 1009 */ 1010 int disposition; 1011 1012 enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed. 1013 1014 /** 1015 * sample aspect ratio (0 if unknown) 1016 * - encoding: Set by user. 1017 * - decoding: Set by libavformat. 1018 */ 1019 AVRational sample_aspect_ratio; 1020 1021 AVDictionary *metadata; 1022 1023 /** 1024 * Average framerate 1025 * 1026 * - demuxing: May be set by libavformat when creating the stream or in 1027 * avformat_find_stream_info(). 1028 * - muxing: May be set by the caller before avformat_write_header(). 1029 */ 1030 AVRational avg_frame_rate; 1031 1032 /** 1033 * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet 1034 * will contain the attached picture. 1035 * 1036 * decoding: set by libavformat, must not be modified by the caller. 1037 * encoding: unused 1038 */ 1039 AVPacket attached_pic; 1040 1041 /** 1042 * An array of side data that applies to the whole stream (i.e. the 1043 * container does not allow it to change between packets). 1044 * 1045 * There may be no overlap between the side data in this array and side data 1046 * in the packets. I.e. a given side data is either exported by the muxer 1047 * (demuxing) / set by the caller (muxing) in this array, then it never 1048 * appears in the packets, or the side data is exported / sent through 1049 * the packets (always in the first packet where the value becomes known or 1050 * changes), then it does not appear in this array. 1051 * 1052 * - demuxing: Set by libavformat when the stream is created. 1053 * - muxing: May be set by the caller before avformat_write_header(). 1054 * 1055 * Freed by libavformat in avformat_free_context(). 1056 * 1057 * @see av_format_inject_global_side_data() 1058 */ 1059 AVPacketSideData *side_data; 1060 /** 1061 * The number of elements in the AVStream.side_data array. 1062 */ 1063 int nb_side_data; 1064 1065 /** 1066 * Flags indicating events happening on the stream, a combination of 1067 * AVSTREAM_EVENT_FLAG_*. 1068 * 1069 * - demuxing: may be set by the demuxer in avformat_open_input(), 1070 * avformat_find_stream_info() and av_read_frame(). Flags must be cleared 1071 * by the user once the event has been handled. 1072 * - muxing: may be set by the user after avformat_write_header(). to 1073 * indicate a user-triggered event. The muxer will clear the flags for 1074 * events it has handled in av_[interleaved]_write_frame(). 1075 */ 1076 int event_flags; 1077 /** 1078 * - demuxing: the demuxer read new metadata from the file and updated 1079 * AVStream.metadata accordingly 1080 * - muxing: the user updated AVStream.metadata and wishes the muxer to write 1081 * it into the file 1082 */ 1083 #define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001 1084 /** 1085 * - demuxing: new packets for this stream were read from the file. This 1086 * event is informational only and does not guarantee that new packets 1087 * for this stream will necessarily be returned from av_read_frame(). 1088 */ 1089 #define AVSTREAM_EVENT_FLAG_NEW_PACKETS (1 << 1) 1090 1091 /** 1092 * Real base framerate of the stream. 1093 * This is the lowest framerate with which all timestamps can be 1094 * represented accurately (it is the least common multiple of all 1095 * framerates in the stream). Note, this value is just a guess! 1096 * For example, if the time base is 1/90000 and all frames have either 1097 * approximately 3600 or 1800 timer ticks, then r_frame_rate will be 50/1. 1098 */ 1099 AVRational r_frame_rate; 1100 1101 /** 1102 * Codec parameters associated with this stream. Allocated and freed by 1103 * libavformat in avformat_new_stream() and avformat_free_context() 1104 * respectively. 1105 * 1106 * - demuxing: filled by libavformat on stream creation or in 1107 * avformat_find_stream_info() 1108 * - muxing: filled by the caller before avformat_write_header() 1109 */ 1110 AVCodecParameters *codecpar; 1111 1112 /** 1113 * Number of bits in timestamps. Used for wrapping control. 1114 * 1115 * - demuxing: set by libavformat 1116 * - muxing: set by libavformat 1117 * 1118 */ 1119 int pts_wrap_bits; 1120 } AVStream; 1121 1122 struct AVCodecParserContext *av_stream_get_parser(const AVStream *s); 1123 1124 /** 1125 * Returns the pts of the last muxed packet + its duration 1126 * 1127 * the retuned value is undefined when used with a demuxer. 1128 */ 1129 int64_t av_stream_get_end_pts(const AVStream *st); 1130 1131 #define AV_PROGRAM_RUNNING 1 1132 1133 /** 1134 * New fields can be added to the end with minor version bumps. 1135 * Removal, reordering and changes to existing fields require a major 1136 * version bump. 1137 * sizeof(AVProgram) must not be used outside libav*. 1138 */ 1139 typedef struct AVProgram { 1140 int id; 1141 int flags; 1142 enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller 1143 unsigned int *stream_index; 1144 unsigned int nb_stream_indexes; 1145 AVDictionary *metadata; 1146 1147 int program_num; 1148 int pmt_pid; 1149 int pcr_pid; 1150 int pmt_version; 1151 1152 /***************************************************************** 1153 * All fields below this line are not part of the public API. They 1154 * may not be used outside of libavformat and can be changed and 1155 * removed at will. 1156 * New public fields should be added right above. 1157 ***************************************************************** 1158 */ 1159 int64_t start_time; 1160 int64_t end_time; 1161 1162 int64_t pts_wrap_reference; ///< reference dts for wrap detection 1163 int pts_wrap_behavior; ///< behavior on wrap detection 1164 } AVProgram; 1165 1166 #define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present 1167 (streams are added dynamically) */ 1168 #define AVFMTCTX_UNSEEKABLE 0x0002 /**< signal that the stream is definitely 1169 not seekable, and attempts to call the 1170 seek function will fail. For some 1171 network protocols (e.g. HLS), this can 1172 change dynamically at runtime. */ 1173 1174 typedef struct AVChapter { 1175 int64_t id; ///< unique ID to identify the chapter 1176 AVRational time_base; ///< time base in which the start/end timestamps are specified 1177 int64_t start, end; ///< chapter start/end time in time_base units 1178 AVDictionary *metadata; 1179 } AVChapter; 1180 1181 1182 /** 1183 * Callback used by devices to communicate with application. 1184 */ 1185 typedef int (*av_format_control_message)(struct AVFormatContext *s, int type, 1186 void *data, size_t data_size); 1187 1188 typedef int (*AVOpenCallback)(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags, 1189 const AVIOInterruptCB *int_cb, AVDictionary **options); 1190 1191 /** 1192 * The duration of a video can be estimated through various ways, and this enum can be used 1193 * to know how the duration was estimated. 1194 */ 1195 enum AVDurationEstimationMethod { 1196 AVFMT_DURATION_FROM_PTS, ///< Duration accurately estimated from PTSes 1197 AVFMT_DURATION_FROM_STREAM, ///< Duration estimated from a stream with a known duration 1198 AVFMT_DURATION_FROM_BITRATE ///< Duration estimated from bitrate (less accurate) 1199 }; 1200 1201 /** 1202 * Format I/O context. 1203 * New fields can be added to the end with minor version bumps. 1204 * Removal, reordering and changes to existing fields require a major 1205 * version bump. 1206 * sizeof(AVFormatContext) must not be used outside libav*, use 1207 * avformat_alloc_context() to create an AVFormatContext. 1208 * 1209 * Fields can be accessed through AVOptions (av_opt*), 1210 * the name string used matches the associated command line parameter name and 1211 * can be found in libavformat/options_table.h. 1212 * The AVOption/command line parameter names differ in some cases from the C 1213 * structure field names for historic reasons or brevity. 1214 */ 1215 typedef struct AVFormatContext { 1216 /** 1217 * A class for logging and @ref avoptions. Set by avformat_alloc_context(). 1218 * Exports (de)muxer private options if they exist. 1219 */ 1220 const AVClass *av_class; 1221 1222 /** 1223 * The input container format. 1224 * 1225 * Demuxing only, set by avformat_open_input(). 1226 */ 1227 const struct AVInputFormat *iformat; 1228 1229 /** 1230 * The output container format. 1231 * 1232 * Muxing only, must be set by the caller before avformat_write_header(). 1233 */ 1234 const struct AVOutputFormat *oformat; 1235 1236 /** 1237 * Format private data. This is an AVOptions-enabled struct 1238 * if and only if iformat/oformat.priv_class is not NULL. 1239 * 1240 * - muxing: set by avformat_write_header() 1241 * - demuxing: set by avformat_open_input() 1242 */ 1243 void *priv_data; 1244 1245 /** 1246 * I/O context. 1247 * 1248 * - demuxing: either set by the user before avformat_open_input() (then 1249 * the user must close it manually) or set by avformat_open_input(). 1250 * - muxing: set by the user before avformat_write_header(). The caller must 1251 * take care of closing / freeing the IO context. 1252 * 1253 * Do NOT set this field if AVFMT_NOFILE flag is set in 1254 * iformat/oformat.flags. In such a case, the (de)muxer will handle 1255 * I/O in some other way and this field will be NULL. 1256 */ 1257 AVIOContext *pb; 1258 1259 /* stream info */ 1260 /** 1261 * Flags signalling stream properties. A combination of AVFMTCTX_*. 1262 * Set by libavformat. 1263 */ 1264 int ctx_flags; 1265 1266 /** 1267 * Number of elements in AVFormatContext.streams. 1268 * 1269 * Set by avformat_new_stream(), must not be modified by any other code. 1270 */ 1271 unsigned int nb_streams; 1272 /** 1273 * A list of all streams in the file. New streams are created with 1274 * avformat_new_stream(). 1275 * 1276 * - demuxing: streams are created by libavformat in avformat_open_input(). 1277 * If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also 1278 * appear in av_read_frame(). 1279 * - muxing: streams are created by the user before avformat_write_header(). 1280 * 1281 * Freed by libavformat in avformat_free_context(). 1282 */ 1283 AVStream **streams; 1284 1285 /** 1286 * input or output URL. Unlike the old filename field, this field has no 1287 * length restriction. 1288 * 1289 * - demuxing: set by avformat_open_input(), initialized to an empty 1290 * string if url parameter was NULL in avformat_open_input(). 1291 * - muxing: may be set by the caller before calling avformat_write_header() 1292 * (or avformat_init_output() if that is called first) to a string 1293 * which is freeable by av_free(). Set to an empty string if it 1294 * was NULL in avformat_init_output(). 1295 * 1296 * Freed by libavformat in avformat_free_context(). 1297 */ 1298 char *url; 1299 1300 /** 1301 * Position of the first frame of the component, in 1302 * AV_TIME_BASE fractional seconds. NEVER set this value directly: 1303 * It is deduced from the AVStream values. 1304 * 1305 * Demuxing only, set by libavformat. 1306 */ 1307 int64_t start_time; 1308 1309 /** 1310 * Duration of the stream, in AV_TIME_BASE fractional 1311 * seconds. Only set this value if you know none of the individual stream 1312 * durations and also do not set any of them. This is deduced from the 1313 * AVStream values if not set. 1314 * 1315 * Demuxing only, set by libavformat. 1316 */ 1317 int64_t duration; 1318 1319 /** 1320 * Total stream bitrate in bit/s, 0 if not 1321 * available. Never set it directly if the file_size and the 1322 * duration are known as FFmpeg can compute it automatically. 1323 */ 1324 int64_t bit_rate; 1325 1326 unsigned int packet_size; 1327 int max_delay; 1328 1329 /** 1330 * Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*. 1331 * Set by the user before avformat_open_input() / avformat_write_header(). 1332 */ 1333 int flags; 1334 #define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames. 1335 #define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index. 1336 #define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input. 1337 #define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS 1338 #define AVFMT_FLAG_NOFILLIN 0x0010 ///< Do not infer any values from other values, just return what is stored in the container 1339 #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 1340 #define AVFMT_FLAG_NOBUFFER 0x0040 ///< Do not buffer frames when possible 1341 #define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it. 1342 #define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted 1343 #define AVFMT_FLAG_FLUSH_PACKETS 0x0200 ///< Flush the AVIOContext every packet. 1344 /** 1345 * When muxing, try to avoid writing any random/volatile data to the output. 1346 * This includes any random IDs, real-time timestamps/dates, muxer version, etc. 1347 * 1348 * This flag is mainly intended for testing. 1349 */ 1350 #define AVFMT_FLAG_BITEXACT 0x0400 1351 #define AVFMT_FLAG_SORT_DTS 0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down) 1352 #if FF_API_LAVF_PRIV_OPT 1353 #define AVFMT_FLAG_PRIV_OPT 0x20000 ///< Enable use of private options by delaying codec open (deprecated, does nothing) 1354 #endif 1355 #define AVFMT_FLAG_FAST_SEEK 0x80000 ///< Enable fast, but inaccurate seeks for some formats 1356 #define AVFMT_FLAG_SHORTEST 0x100000 ///< Stop muxing when the shortest stream stops. 1357 #define AVFMT_FLAG_AUTO_BSF 0x200000 ///< Add bitstream filters as requested by the muxer 1358 1359 /** 1360 * Maximum number of bytes read from input in order to determine stream 1361 * properties. Used when reading the global header and in 1362 * avformat_find_stream_info(). 1363 * 1364 * Demuxing only, set by the caller before avformat_open_input(). 1365 * 1366 * @note this is \e not used for determining the \ref AVInputFormat 1367 * "input format" 1368 * @sa format_probesize 1369 */ 1370 int64_t probesize; 1371 1372 /** 1373 * Maximum duration (in AV_TIME_BASE units) of the data read 1374 * from input in avformat_find_stream_info(). 1375 * Demuxing only, set by the caller before avformat_find_stream_info(). 1376 * Can be set to 0 to let avformat choose using a heuristic. 1377 */ 1378 int64_t max_analyze_duration; 1379 1380 const uint8_t *key; 1381 int keylen; 1382 1383 unsigned int nb_programs; 1384 AVProgram **programs; 1385 1386 /** 1387 * Forced video codec_id. 1388 * Demuxing: Set by user. 1389 */ 1390 enum AVCodecID video_codec_id; 1391 1392 /** 1393 * Forced audio codec_id. 1394 * Demuxing: Set by user. 1395 */ 1396 enum AVCodecID audio_codec_id; 1397 1398 /** 1399 * Forced subtitle codec_id. 1400 * Demuxing: Set by user. 1401 */ 1402 enum AVCodecID subtitle_codec_id; 1403 1404 /** 1405 * Maximum amount of memory in bytes to use for the index of each stream. 1406 * If the index exceeds this size, entries will be discarded as 1407 * needed to maintain a smaller size. This can lead to slower or less 1408 * accurate seeking (depends on demuxer). 1409 * Demuxers for which a full in-memory index is mandatory will ignore 1410 * this. 1411 * - muxing: unused 1412 * - demuxing: set by user 1413 */ 1414 unsigned int max_index_size; 1415 1416 /** 1417 * Maximum amount of memory in bytes to use for buffering frames 1418 * obtained from realtime capture devices. 1419 */ 1420 unsigned int max_picture_buffer; 1421 1422 /** 1423 * Number of chapters in AVChapter array. 1424 * When muxing, chapters are normally written in the file header, 1425 * so nb_chapters should normally be initialized before write_header 1426 * is called. Some muxers (e.g. mov and mkv) can also write chapters 1427 * in the trailer. To write chapters in the trailer, nb_chapters 1428 * must be zero when write_header is called and non-zero when 1429 * write_trailer is called. 1430 * - muxing: set by user 1431 * - demuxing: set by libavformat 1432 */ 1433 unsigned int nb_chapters; 1434 AVChapter **chapters; 1435 1436 /** 1437 * Metadata that applies to the whole file. 1438 * 1439 * - demuxing: set by libavformat in avformat_open_input() 1440 * - muxing: may be set by the caller before avformat_write_header() 1441 * 1442 * Freed by libavformat in avformat_free_context(). 1443 */ 1444 AVDictionary *metadata; 1445 1446 /** 1447 * Start time of the stream in real world time, in microseconds 1448 * since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the 1449 * stream was captured at this real world time. 1450 * - muxing: Set by the caller before avformat_write_header(). If set to 1451 * either 0 or AV_NOPTS_VALUE, then the current wall-time will 1452 * be used. 1453 * - demuxing: Set by libavformat. AV_NOPTS_VALUE if unknown. Note that 1454 * the value may become known after some number of frames 1455 * have been received. 1456 */ 1457 int64_t start_time_realtime; 1458 1459 /** 1460 * The number of frames used for determining the framerate in 1461 * avformat_find_stream_info(). 1462 * Demuxing only, set by the caller before avformat_find_stream_info(). 1463 */ 1464 int fps_probe_size; 1465 1466 /** 1467 * Error recognition; higher values will detect more errors but may 1468 * misdetect some more or less valid parts as errors. 1469 * Demuxing only, set by the caller before avformat_open_input(). 1470 */ 1471 int error_recognition; 1472 1473 /** 1474 * Custom interrupt callbacks for the I/O layer. 1475 * 1476 * demuxing: set by the user before avformat_open_input(). 1477 * muxing: set by the user before avformat_write_header() 1478 * (mainly useful for AVFMT_NOFILE formats). The callback 1479 * should also be passed to avio_open2() if it's used to 1480 * open the file. 1481 */ 1482 AVIOInterruptCB interrupt_callback; 1483 1484 /** 1485 * Flags to enable debugging. 1486 */ 1487 int debug; 1488 #define FF_FDEBUG_TS 0x0001 1489 1490 /** 1491 * Maximum buffering duration for interleaving. 1492 * 1493 * To ensure all the streams are interleaved correctly, 1494 * av_interleaved_write_frame() will wait until it has at least one packet 1495 * for each stream before actually writing any packets to the output file. 1496 * When some streams are "sparse" (i.e. there are large gaps between 1497 * successive packets), this can result in excessive buffering. 1498 * 1499 * This field specifies the maximum difference between the timestamps of the 1500 * first and the last packet in the muxing queue, above which libavformat 1501 * will output a packet regardless of whether it has queued a packet for all 1502 * the streams. 1503 * 1504 * Muxing only, set by the caller before avformat_write_header(). 1505 */ 1506 int64_t max_interleave_delta; 1507 1508 /** 1509 * Allow non-standard and experimental extension 1510 * @see AVCodecContext.strict_std_compliance 1511 */ 1512 int strict_std_compliance; 1513 1514 /** 1515 * Flags indicating events happening on the file, a combination of 1516 * AVFMT_EVENT_FLAG_*. 1517 * 1518 * - demuxing: may be set by the demuxer in avformat_open_input(), 1519 * avformat_find_stream_info() and av_read_frame(). Flags must be cleared 1520 * by the user once the event has been handled. 1521 * - muxing: may be set by the user after avformat_write_header() to 1522 * indicate a user-triggered event. The muxer will clear the flags for 1523 * events it has handled in av_[interleaved]_write_frame(). 1524 */ 1525 int event_flags; 1526 /** 1527 * - demuxing: the demuxer read new metadata from the file and updated 1528 * AVFormatContext.metadata accordingly 1529 * - muxing: the user updated AVFormatContext.metadata and wishes the muxer to 1530 * write it into the file 1531 */ 1532 #define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001 1533 1534 /** 1535 * Maximum number of packets to read while waiting for the first timestamp. 1536 * Decoding only. 1537 */ 1538 int max_ts_probe; 1539 1540 /** 1541 * Avoid negative timestamps during muxing. 1542 * Any value of the AVFMT_AVOID_NEG_TS_* constants. 1543 * Note, this works better when using av_interleaved_write_frame(). 1544 * - muxing: Set by user 1545 * - demuxing: unused 1546 */ 1547 int avoid_negative_ts; 1548 #define AVFMT_AVOID_NEG_TS_AUTO -1 ///< Enabled when required by target format 1549 #define AVFMT_AVOID_NEG_TS_DISABLED 0 ///< Do not shift timestamps even when they are negative. 1550 #define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative 1551 #define AVFMT_AVOID_NEG_TS_MAKE_ZERO 2 ///< Shift timestamps so that they start at 0 1552 1553 /** 1554 * Transport stream id. 1555 * This will be moved into demuxer private options. Thus no API/ABI compatibility 1556 */ 1557 int ts_id; 1558 1559 /** 1560 * Audio preload in microseconds. 1561 * Note, not all formats support this and unpredictable things may happen if it is used when not supported. 1562 * - encoding: Set by user 1563 * - decoding: unused 1564 */ 1565 int audio_preload; 1566 1567 /** 1568 * Max chunk time in microseconds. 1569 * Note, not all formats support this and unpredictable things may happen if it is used when not supported. 1570 * - encoding: Set by user 1571 * - decoding: unused 1572 */ 1573 int max_chunk_duration; 1574 1575 /** 1576 * Max chunk size in bytes 1577 * Note, not all formats support this and unpredictable things may happen if it is used when not supported. 1578 * - encoding: Set by user 1579 * - decoding: unused 1580 */ 1581 int max_chunk_size; 1582 1583 /** 1584 * forces the use of wallclock timestamps as pts/dts of packets 1585 * This has undefined results in the presence of B frames. 1586 * - encoding: unused 1587 * - decoding: Set by user 1588 */ 1589 int use_wallclock_as_timestamps; 1590 1591 /** 1592 * avio flags, used to force AVIO_FLAG_DIRECT. 1593 * - encoding: unused 1594 * - decoding: Set by user 1595 */ 1596 int avio_flags; 1597 1598 /** 1599 * The duration field can be estimated through various ways, and this field can be used 1600 * to know how the duration was estimated. 1601 * - encoding: unused 1602 * - decoding: Read by user 1603 */ 1604 enum AVDurationEstimationMethod duration_estimation_method; 1605 1606 /** 1607 * Skip initial bytes when opening stream 1608 * - encoding: unused 1609 * - decoding: Set by user 1610 */ 1611 int64_t skip_initial_bytes; 1612 1613 /** 1614 * Correct single timestamp overflows 1615 * - encoding: unused 1616 * - decoding: Set by user 1617 */ 1618 unsigned int correct_ts_overflow; 1619 1620 /** 1621 * Force seeking to any (also non key) frames. 1622 * - encoding: unused 1623 * - decoding: Set by user 1624 */ 1625 int seek2any; 1626 1627 /** 1628 * Flush the I/O context after each packet. 1629 * - encoding: Set by user 1630 * - decoding: unused 1631 */ 1632 int flush_packets; 1633 1634 /** 1635 * format probing score. 1636 * The maximal score is AVPROBE_SCORE_MAX, its set when the demuxer probes 1637 * the format. 1638 * - encoding: unused 1639 * - decoding: set by avformat, read by user 1640 */ 1641 int probe_score; 1642 1643 /** 1644 * Maximum number of bytes read from input in order to identify the 1645 * \ref AVInputFormat "input format". Only used when the format is not set 1646 * explicitly by the caller. 1647 * 1648 * Demuxing only, set by the caller before avformat_open_input(). 1649 * 1650 * @sa probesize 1651 */ 1652 int format_probesize; 1653 1654 /** 1655 * ',' separated list of allowed decoders. 1656 * If NULL then all are allowed 1657 * - encoding: unused 1658 * - decoding: set by user 1659 */ 1660 char *codec_whitelist; 1661 1662 /** 1663 * ',' separated list of allowed demuxers. 1664 * If NULL then all are allowed 1665 * - encoding: unused 1666 * - decoding: set by user 1667 */ 1668 char *format_whitelist; 1669 1670 /** 1671 * IO repositioned flag. 1672 * This is set by avformat when the underlaying IO context read pointer 1673 * is repositioned, for example when doing byte based seeking. 1674 * Demuxers can use the flag to detect such changes. 1675 */ 1676 int io_repositioned; 1677 1678 /** 1679 * Forced video codec. 1680 * This allows forcing a specific decoder, even when there are multiple with 1681 * the same codec_id. 1682 * Demuxing: Set by user 1683 */ 1684 const AVCodec *video_codec; 1685 1686 /** 1687 * Forced audio codec. 1688 * This allows forcing a specific decoder, even when there are multiple with 1689 * the same codec_id. 1690 * Demuxing: Set by user 1691 */ 1692 const AVCodec *audio_codec; 1693 1694 /** 1695 * Forced subtitle codec. 1696 * This allows forcing a specific decoder, even when there are multiple with 1697 * the same codec_id. 1698 * Demuxing: Set by user 1699 */ 1700 const AVCodec *subtitle_codec; 1701 1702 /** 1703 * Forced data codec. 1704 * This allows forcing a specific decoder, even when there are multiple with 1705 * the same codec_id. 1706 * Demuxing: Set by user 1707 */ 1708 const AVCodec *data_codec; 1709 1710 /** 1711 * Number of bytes to be written as padding in a metadata header. 1712 * Demuxing: Unused. 1713 * Muxing: Set by user via av_format_set_metadata_header_padding. 1714 */ 1715 int metadata_header_padding; 1716 1717 /** 1718 * User data. 1719 * This is a place for some private data of the user. 1720 */ 1721 void *opaque; 1722 1723 /** 1724 * Callback used by devices to communicate with application. 1725 */ 1726 av_format_control_message control_message_cb; 1727 1728 /** 1729 * Output timestamp offset, in microseconds. 1730 * Muxing: set by user 1731 */ 1732 int64_t output_ts_offset; 1733 1734 /** 1735 * dump format separator. 1736 * can be ", " or "\n " or anything else 1737 * - muxing: Set by user. 1738 * - demuxing: Set by user. 1739 */ 1740 uint8_t *dump_separator; 1741 1742 /** 1743 * Forced Data codec_id. 1744 * Demuxing: Set by user. 1745 */ 1746 enum AVCodecID data_codec_id; 1747 1748 /** 1749 * ',' separated list of allowed protocols. 1750 * - encoding: unused 1751 * - decoding: set by user 1752 */ 1753 char *protocol_whitelist; 1754 1755 /** 1756 * A callback for opening new IO streams. 1757 * 1758 * Whenever a muxer or a demuxer needs to open an IO stream (typically from 1759 * avformat_open_input() for demuxers, but for certain formats can happen at 1760 * other times as well), it will call this callback to obtain an IO context. 1761 * 1762 * @param s the format context 1763 * @param pb on success, the newly opened IO context should be returned here 1764 * @param url the url to open 1765 * @param flags a combination of AVIO_FLAG_* 1766 * @param options a dictionary of additional options, with the same 1767 * semantics as in avio_open2() 1768 * @return 0 on success, a negative AVERROR code on failure 1769 * 1770 * @note Certain muxers and demuxers do nesting, i.e. they open one or more 1771 * additional internal format contexts. Thus the AVFormatContext pointer 1772 * passed to this callback may be different from the one facing the caller. 1773 * It will, however, have the same 'opaque' field. 1774 */ 1775 int (*io_open)(struct AVFormatContext *s, AVIOContext **pb, const char *url, 1776 int flags, AVDictionary **options); 1777 1778 /** 1779 * A callback for closing the streams opened with AVFormatContext.io_open(). 1780 */ 1781 void (*io_close)(struct AVFormatContext *s, AVIOContext *pb); 1782 1783 /** 1784 * ',' separated list of disallowed protocols. 1785 * - encoding: unused 1786 * - decoding: set by user 1787 */ 1788 char *protocol_blacklist; 1789 1790 /** 1791 * The maximum number of streams. 1792 * - encoding: unused 1793 * - decoding: set by user 1794 */ 1795 int max_streams; 1796 1797 /** 1798 * Skip duration calcuation in estimate_timings_from_pts. 1799 * - encoding: unused 1800 * - decoding: set by user 1801 */ 1802 int skip_estimate_duration_from_pts; 1803 1804 /** 1805 * Maximum number of packets that can be probed 1806 * - encoding: unused 1807 * - decoding: set by user 1808 */ 1809 int max_probe_packets; 1810 1811 /** 1812 * A callback for closing the streams opened with AVFormatContext.io_open(). 1813 * 1814 * Using this is preferred over io_close, because this can return an error. 1815 * Therefore this callback is used instead of io_close by the generic 1816 * libavformat code if io_close is NULL or the default. 1817 * 1818 * @param s the format context 1819 * @param pb IO context to be closed and freed 1820 * @return 0 on success, a negative AVERROR code on failure 1821 */ 1822 int (*io_close2)(struct AVFormatContext *s, AVIOContext *pb); 1823 } AVFormatContext; 1824 1825 /** 1826 * This function will cause global side data to be injected in the next packet 1827 * of each stream as well as after any subsequent seek. 1828 */ 1829 void av_format_inject_global_side_data(AVFormatContext *s); 1830 1831 /** 1832 * Returns the method used to set ctx->duration. 1833 * 1834 * @return AVFMT_DURATION_FROM_PTS, AVFMT_DURATION_FROM_STREAM, or AVFMT_DURATION_FROM_BITRATE. 1835 */ 1836 enum AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext* ctx); 1837 1838 /** 1839 * @defgroup lavf_core Core functions 1840 * @ingroup libavf 1841 * 1842 * Functions for querying libavformat capabilities, allocating core structures, 1843 * etc. 1844 * @{ 1845 */ 1846 1847 /** 1848 * Return the LIBAVFORMAT_VERSION_INT constant. 1849 */ 1850 unsigned avformat_version(void); 1851 1852 /** 1853 * Return the libavformat build-time configuration. 1854 */ 1855 const char *avformat_configuration(void); 1856 1857 /** 1858 * Return the libavformat license. 1859 */ 1860 const char *avformat_license(void); 1861 1862 /** 1863 * Do global initialization of network libraries. This is optional, 1864 * and not recommended anymore. 1865 * 1866 * This functions only exists to work around thread-safety issues 1867 * with older GnuTLS or OpenSSL libraries. If libavformat is linked 1868 * to newer versions of those libraries, or if you do not use them, 1869 * calling this function is unnecessary. Otherwise, you need to call 1870 * this function before any other threads using them are started. 1871 * 1872 * This function will be deprecated once support for older GnuTLS and 1873 * OpenSSL libraries is removed, and this function has no purpose 1874 * anymore. 1875 */ 1876 int avformat_network_init(void); 1877 1878 /** 1879 * Undo the initialization done by avformat_network_init. Call it only 1880 * once for each time you called avformat_network_init. 1881 */ 1882 int avformat_network_deinit(void); 1883 1884 /** 1885 * Iterate over all registered muxers. 1886 * 1887 * @param opaque a pointer where libavformat will store the iteration state. Must 1888 * point to NULL to start the iteration. 1889 * 1890 * @return the next registered muxer or NULL when the iteration is 1891 * finished 1892 */ 1893 const AVOutputFormat *av_muxer_iterate(void **opaque); 1894 1895 /** 1896 * Iterate over all registered demuxers. 1897 * 1898 * @param opaque a pointer where libavformat will store the iteration state. Must 1899 * point to NULL to start the iteration. 1900 * 1901 * @return the next registered demuxer or NULL when the iteration is 1902 * finished 1903 */ 1904 const AVInputFormat *av_demuxer_iterate(void **opaque); 1905 1906 /** 1907 * Allocate an AVFormatContext. 1908 * avformat_free_context() can be used to free the context and everything 1909 * allocated by the framework within it. 1910 */ 1911 AVFormatContext *avformat_alloc_context(void); 1912 1913 /** 1914 * Free an AVFormatContext and all its streams. 1915 * @param s context to free 1916 */ 1917 void avformat_free_context(AVFormatContext *s); 1918 1919 /** 1920 * Get the AVClass for AVFormatContext. It can be used in combination with 1921 * AV_OPT_SEARCH_FAKE_OBJ for examining options. 1922 * 1923 * @see av_opt_find(). 1924 */ 1925 const AVClass *avformat_get_class(void); 1926 1927 /** 1928 * Get the AVClass for AVStream. It can be used in combination with 1929 * AV_OPT_SEARCH_FAKE_OBJ for examining options. 1930 * 1931 * @see av_opt_find(). 1932 */ 1933 const AVClass *av_stream_get_class(void); 1934 1935 /** 1936 * Add a new stream to a media file. 1937 * 1938 * When demuxing, it is called by the demuxer in read_header(). If the 1939 * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also 1940 * be called in read_packet(). 1941 * 1942 * When muxing, should be called by the user before avformat_write_header(). 1943 * 1944 * User is required to call avformat_free_context() to clean up the allocation 1945 * by avformat_new_stream(). 1946 * 1947 * @param s media file handle 1948 * @param c unused, does nothing 1949 * 1950 * @return newly created stream or NULL on error. 1951 */ 1952 AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c); 1953 1954 /** 1955 * Wrap an existing array as stream side data. 1956 * 1957 * @param st stream 1958 * @param type side information type 1959 * @param data the side data array. It must be allocated with the av_malloc() 1960 * family of functions. The ownership of the data is transferred to 1961 * st. 1962 * @param size side information size 1963 * @return zero on success, a negative AVERROR code on failure. On failure, 1964 * the stream is unchanged and the data remains owned by the caller. 1965 */ 1966 int av_stream_add_side_data(AVStream *st, enum AVPacketSideDataType type, 1967 uint8_t *data, size_t size); 1968 1969 /** 1970 * Allocate new information from stream. 1971 * 1972 * @param stream stream 1973 * @param type desired side information type 1974 * @param size side information size 1975 * @return pointer to fresh allocated data or NULL otherwise 1976 */ 1977 uint8_t *av_stream_new_side_data(AVStream *stream, 1978 enum AVPacketSideDataType type, size_t size); 1979 /** 1980 * Get side information from stream. 1981 * 1982 * @param stream stream 1983 * @param type desired side information type 1984 * @param size If supplied, *size will be set to the size of the side data 1985 * or to zero if the desired side data is not present. 1986 * @return pointer to data if present or NULL otherwise 1987 */ 1988 uint8_t *av_stream_get_side_data(const AVStream *stream, 1989 enum AVPacketSideDataType type, size_t *size); 1990 1991 AVProgram *av_new_program(AVFormatContext *s, int id); 1992 1993 /** 1994 * @} 1995 */ 1996 1997 1998 /** 1999 * Allocate an AVFormatContext for an output format. 2000 * avformat_free_context() can be used to free the context and 2001 * everything allocated by the framework within it. 2002 * 2003 * @param *ctx is set to the created format context, or to NULL in 2004 * case of failure 2005 * @param oformat format to use for allocating the context, if NULL 2006 * format_name and filename are used instead 2007 * @param format_name the name of output format to use for allocating the 2008 * context, if NULL filename is used instead 2009 * @param filename the name of the filename to use for allocating the 2010 * context, may be NULL 2011 * @return >= 0 in case of success, a negative AVERROR code in case of 2012 * failure 2013 */ 2014 int avformat_alloc_output_context2(AVFormatContext **ctx, const AVOutputFormat *oformat, 2015 const char *format_name, const char *filename); 2016 2017 /** 2018 * @addtogroup lavf_decoding 2019 * @{ 2020 */ 2021 2022 /** 2023 * Find AVInputFormat based on the short name of the input format. 2024 */ 2025 const AVInputFormat *av_find_input_format(const char *short_name); 2026 2027 /** 2028 * Guess the file format. 2029 * 2030 * @param pd data to be probed 2031 * @param is_opened Whether the file is already opened; determines whether 2032 * demuxers with or without AVFMT_NOFILE are probed. 2033 */ 2034 const AVInputFormat *av_probe_input_format(const AVProbeData *pd, int is_opened); 2035 2036 /** 2037 * Guess the file format. 2038 * 2039 * @param pd data to be probed 2040 * @param is_opened Whether the file is already opened; determines whether 2041 * demuxers with or without AVFMT_NOFILE are probed. 2042 * @param score_max A probe score larger that this is required to accept a 2043 * detection, the variable is set to the actual detection 2044 * score afterwards. 2045 * If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended 2046 * to retry with a larger probe buffer. 2047 */ 2048 const AVInputFormat *av_probe_input_format2(const AVProbeData *pd, 2049 int is_opened, int *score_max); 2050 2051 /** 2052 * Guess the file format. 2053 * 2054 * @param is_opened Whether the file is already opened; determines whether 2055 * demuxers with or without AVFMT_NOFILE are probed. 2056 * @param score_ret The score of the best detection. 2057 */ 2058 const AVInputFormat *av_probe_input_format3(const AVProbeData *pd, 2059 int is_opened, int *score_ret); 2060 2061 /** 2062 * Probe a bytestream to determine the input format. Each time a probe returns 2063 * with a score that is too low, the probe buffer size is increased and another 2064 * attempt is made. When the maximum probe size is reached, the input format 2065 * with the highest score is returned. 2066 * 2067 * @param pb the bytestream to probe 2068 * @param fmt the input format is put here 2069 * @param url the url of the stream 2070 * @param logctx the log context 2071 * @param offset the offset within the bytestream to probe from 2072 * @param max_probe_size the maximum probe buffer size (zero for default) 2073 * @return the score in case of success, a negative value corresponding to an 2074 * the maximal score is AVPROBE_SCORE_MAX 2075 * AVERROR code otherwise 2076 */ 2077 int av_probe_input_buffer2(AVIOContext *pb, const AVInputFormat **fmt, 2078 const char *url, void *logctx, 2079 unsigned int offset, unsigned int max_probe_size); 2080 2081 /** 2082 * Like av_probe_input_buffer2() but returns 0 on success 2083 */ 2084 int av_probe_input_buffer(AVIOContext *pb, const AVInputFormat **fmt, 2085 const char *url, void *logctx, 2086 unsigned int offset, unsigned int max_probe_size); 2087 2088 /** 2089 * Open an input stream and read the header. The codecs are not opened. 2090 * The stream must be closed with avformat_close_input(). 2091 * 2092 * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context). 2093 * May be a pointer to NULL, in which case an AVFormatContext is allocated by this 2094 * function and written into ps. 2095 * Note that a user-supplied AVFormatContext will be freed on failure. 2096 * @param url URL of the stream to open. 2097 * @param fmt If non-NULL, this parameter forces a specific input format. 2098 * Otherwise the format is autodetected. 2099 * @param options A dictionary filled with AVFormatContext and demuxer-private options. 2100 * On return this parameter will be destroyed and replaced with a dict containing 2101 * options that were not found. May be NULL. 2102 * 2103 * @return 0 on success, a negative AVERROR on failure. 2104 * 2105 * @note If you want to use custom IO, preallocate the format context and set its pb field. 2106 */ 2107 int avformat_open_input(AVFormatContext **ps, const char *url, 2108 const AVInputFormat *fmt, AVDictionary **options); 2109 2110 /** 2111 * Read packets of a media file to get stream information. This 2112 * is useful for file formats with no headers such as MPEG. This 2113 * function also computes the real framerate in case of MPEG-2 repeat 2114 * frame mode. 2115 * The logical file position is not changed by this function; 2116 * examined packets may be buffered for later processing. 2117 * 2118 * @param ic media file handle 2119 * @param options If non-NULL, an ic.nb_streams long array of pointers to 2120 * dictionaries, where i-th member contains options for 2121 * codec corresponding to i-th stream. 2122 * On return each dictionary will be filled with options that were not found. 2123 * @return >=0 if OK, AVERROR_xxx on error 2124 * 2125 * @note this function isn't guaranteed to open all the codecs, so 2126 * options being non-empty at return is a perfectly normal behavior. 2127 * 2128 * @todo Let the user decide somehow what information is needed so that 2129 * we do not waste time getting stuff the user does not need. 2130 */ 2131 int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options); 2132 2133 /** 2134 * Find the programs which belong to a given stream. 2135 * 2136 * @param ic media file handle 2137 * @param last the last found program, the search will start after this 2138 * program, or from the beginning if it is NULL 2139 * @param s stream index 2140 * @return the next program which belongs to s, NULL if no program is found or 2141 * the last program is not among the programs of ic. 2142 */ 2143 AVProgram *av_find_program_from_stream(AVFormatContext *ic, AVProgram *last, int s); 2144 2145 void av_program_add_stream_index(AVFormatContext *ac, int progid, unsigned int idx); 2146 2147 /** 2148 * Find the "best" stream in the file. 2149 * The best stream is determined according to various heuristics as the most 2150 * likely to be what the user expects. 2151 * If the decoder parameter is non-NULL, av_find_best_stream will find the 2152 * default decoder for the stream's codec; streams for which no decoder can 2153 * be found are ignored. 2154 * 2155 * @param ic media file handle 2156 * @param type stream type: video, audio, subtitles, etc. 2157 * @param wanted_stream_nb user-requested stream number, 2158 * or -1 for automatic selection 2159 * @param related_stream try to find a stream related (eg. in the same 2160 * program) to this one, or -1 if none 2161 * @param decoder_ret if non-NULL, returns the decoder for the 2162 * selected stream 2163 * @param flags flags; none are currently defined 2164 * @return the non-negative stream number in case of success, 2165 * AVERROR_STREAM_NOT_FOUND if no stream with the requested type 2166 * could be found, 2167 * AVERROR_DECODER_NOT_FOUND if streams were found but no decoder 2168 * @note If av_find_best_stream returns successfully and decoder_ret is not 2169 * NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec. 2170 */ 2171 int av_find_best_stream(AVFormatContext *ic, 2172 enum AVMediaType type, 2173 int wanted_stream_nb, 2174 int related_stream, 2175 const AVCodec **decoder_ret, 2176 int flags); 2177 2178 /** 2179 * Return the next frame of a stream. 2180 * This function returns what is stored in the file, and does not validate 2181 * that what is there are valid frames for the decoder. It will split what is 2182 * stored in the file into frames and return one for each call. It will not 2183 * omit invalid data between valid frames so as to give the decoder the maximum 2184 * information possible for decoding. 2185 * 2186 * On success, the returned packet is reference-counted (pkt->buf is set) and 2187 * valid indefinitely. The packet must be freed with av_packet_unref() when 2188 * it is no longer needed. For video, the packet contains exactly one frame. 2189 * For audio, it contains an integer number of frames if each frame has 2190 * a known fixed size (e.g. PCM or ADPCM data). If the audio frames have 2191 * a variable size (e.g. MPEG audio), then it contains one frame. 2192 * 2193 * pkt->pts, pkt->dts and pkt->duration are always set to correct 2194 * values in AVStream.time_base units (and guessed if the format cannot 2195 * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format 2196 * has B-frames, so it is better to rely on pkt->dts if you do not 2197 * decompress the payload. 2198 * 2199 * @return 0 if OK, < 0 on error or end of file. On error, pkt will be blank 2200 * (as if it came from av_packet_alloc()). 2201 * 2202 * @note pkt will be initialized, so it may be uninitialized, but it must not 2203 * contain data that needs to be freed. 2204 */ 2205 int av_read_frame(AVFormatContext *s, AVPacket *pkt); 2206 2207 /** 2208 * Seek to the keyframe at timestamp. 2209 * 'timestamp' in 'stream_index'. 2210 * 2211 * @param s media file handle 2212 * @param stream_index If stream_index is (-1), a default 2213 * stream is selected, and timestamp is automatically converted 2214 * from AV_TIME_BASE units to the stream specific time_base. 2215 * @param timestamp Timestamp in AVStream.time_base units 2216 * or, if no stream is specified, in AV_TIME_BASE units. 2217 * @param flags flags which select direction and seeking mode 2218 * @return >= 0 on success 2219 */ 2220 int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp, 2221 int flags); 2222 2223 /** 2224 * Seek to timestamp ts. 2225 * Seeking will be done so that the point from which all active streams 2226 * can be presented successfully will be closest to ts and within min/max_ts. 2227 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL. 2228 * 2229 * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and 2230 * are the file position (this may not be supported by all demuxers). 2231 * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames 2232 * in the stream with stream_index (this may not be supported by all demuxers). 2233 * Otherwise all timestamps are in units of the stream selected by stream_index 2234 * or if stream_index is -1, in AV_TIME_BASE units. 2235 * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as 2236 * keyframes (this may not be supported by all demuxers). 2237 * If flags contain AVSEEK_FLAG_BACKWARD, it is ignored. 2238 * 2239 * @param s media file handle 2240 * @param stream_index index of the stream which is used as time base reference 2241 * @param min_ts smallest acceptable timestamp 2242 * @param ts target timestamp 2243 * @param max_ts largest acceptable timestamp 2244 * @param flags flags 2245 * @return >=0 on success, error code otherwise 2246 * 2247 * @note This is part of the new seek API which is still under construction. 2248 */ 2249 int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags); 2250 2251 /** 2252 * Discard all internally buffered data. This can be useful when dealing with 2253 * discontinuities in the byte stream. Generally works only with formats that 2254 * can resync. This includes headerless formats like MPEG-TS/TS but should also 2255 * work with NUT, Ogg and in a limited way AVI for example. 2256 * 2257 * The set of streams, the detected duration, stream parameters and codecs do 2258 * not change when calling this function. If you want a complete reset, it's 2259 * better to open a new AVFormatContext. 2260 * 2261 * This does not flush the AVIOContext (s->pb). If necessary, call 2262 * avio_flush(s->pb) before calling this function. 2263 * 2264 * @param s media file handle 2265 * @return >=0 on success, error code otherwise 2266 */ 2267 int avformat_flush(AVFormatContext *s); 2268 2269 /** 2270 * Start playing a network-based stream (e.g. RTSP stream) at the 2271 * current position. 2272 */ 2273 int av_read_play(AVFormatContext *s); 2274 2275 /** 2276 * Pause a network-based stream (e.g. RTSP stream). 2277 * 2278 * Use av_read_play() to resume it. 2279 */ 2280 int av_read_pause(AVFormatContext *s); 2281 2282 /** 2283 * Close an opened input AVFormatContext. Free it and all its contents 2284 * and set *s to NULL. 2285 */ 2286 void avformat_close_input(AVFormatContext **s); 2287 /** 2288 * @} 2289 */ 2290 2291 #define AVSEEK_FLAG_BACKWARD 1 ///< seek backward 2292 #define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes 2293 #define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes 2294 #define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number 2295 2296 /** 2297 * @addtogroup lavf_encoding 2298 * @{ 2299 */ 2300 2301 #define AVSTREAM_INIT_IN_WRITE_HEADER 0 ///< stream parameters initialized in avformat_write_header 2302 #define AVSTREAM_INIT_IN_INIT_OUTPUT 1 ///< stream parameters initialized in avformat_init_output 2303 2304 /** 2305 * Allocate the stream private data and write the stream header to 2306 * an output media file. 2307 * 2308 * @param s Media file handle, must be allocated with avformat_alloc_context(). 2309 * Its oformat field must be set to the desired output format; 2310 * Its pb field must be set to an already opened AVIOContext. 2311 * @param options An AVDictionary filled with AVFormatContext and muxer-private options. 2312 * On return this parameter will be destroyed and replaced with a dict containing 2313 * options that were not found. May be NULL. 2314 * 2315 * @return AVSTREAM_INIT_IN_WRITE_HEADER on success if the codec had not already been fully initialized in avformat_init, 2316 * AVSTREAM_INIT_IN_INIT_OUTPUT on success if the codec had already been fully initialized in avformat_init, 2317 * negative AVERROR on failure. 2318 * 2319 * @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_init_output. 2320 */ 2321 av_warn_unused_result 2322 int avformat_write_header(AVFormatContext *s, AVDictionary **options); 2323 2324 /** 2325 * Allocate the stream private data and initialize the codec, but do not write the header. 2326 * May optionally be used before avformat_write_header to initialize stream parameters 2327 * before actually writing the header. 2328 * If using this function, do not pass the same options to avformat_write_header. 2329 * 2330 * @param s Media file handle, must be allocated with avformat_alloc_context(). 2331 * Its oformat field must be set to the desired output format; 2332 * Its pb field must be set to an already opened AVIOContext. 2333 * @param options An AVDictionary filled with AVFormatContext and muxer-private options. 2334 * On return this parameter will be destroyed and replaced with a dict containing 2335 * options that were not found. May be NULL. 2336 * 2337 * @return AVSTREAM_INIT_IN_WRITE_HEADER on success if the codec requires avformat_write_header to fully initialize, 2338 * AVSTREAM_INIT_IN_INIT_OUTPUT on success if the codec has been fully initialized, 2339 * negative AVERROR on failure. 2340 * 2341 * @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_write_header. 2342 */ 2343 av_warn_unused_result 2344 int avformat_init_output(AVFormatContext *s, AVDictionary **options); 2345 2346 /** 2347 * Write a packet to an output media file. 2348 * 2349 * This function passes the packet directly to the muxer, without any buffering 2350 * or reordering. The caller is responsible for correctly interleaving the 2351 * packets if the format requires it. Callers that want libavformat to handle 2352 * the interleaving should call av_interleaved_write_frame() instead of this 2353 * function. 2354 * 2355 * @param s media file handle 2356 * @param pkt The packet containing the data to be written. Note that unlike 2357 * av_interleaved_write_frame(), this function does not take 2358 * ownership of the packet passed to it (though some muxers may make 2359 * an internal reference to the input packet). 2360 * <br> 2361 * This parameter can be NULL (at any time, not just at the end), in 2362 * order to immediately flush data buffered within the muxer, for 2363 * muxers that buffer up data internally before writing it to the 2364 * output. 2365 * <br> 2366 * Packet's @ref AVPacket.stream_index "stream_index" field must be 2367 * set to the index of the corresponding stream in @ref 2368 * AVFormatContext.streams "s->streams". 2369 * <br> 2370 * The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts") 2371 * must be set to correct values in the stream's timebase (unless the 2372 * output format is flagged with the AVFMT_NOTIMESTAMPS flag, then 2373 * they can be set to AV_NOPTS_VALUE). 2374 * The dts for subsequent packets passed to this function must be strictly 2375 * increasing when compared in their respective timebases (unless the 2376 * output format is flagged with the AVFMT_TS_NONSTRICT, then they 2377 * merely have to be nondecreasing). @ref AVPacket.duration 2378 * "duration") should also be set if known. 2379 * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush 2380 * 2381 * @see av_interleaved_write_frame() 2382 */ 2383 int av_write_frame(AVFormatContext *s, AVPacket *pkt); 2384 2385 /** 2386 * Write a packet to an output media file ensuring correct interleaving. 2387 * 2388 * This function will buffer the packets internally as needed to make sure the 2389 * packets in the output file are properly interleaved, usually ordered by 2390 * increasing dts. Callers doing their own interleaving should call 2391 * av_write_frame() instead of this function. 2392 * 2393 * Using this function instead of av_write_frame() can give muxers advance 2394 * knowledge of future packets, improving e.g. the behaviour of the mp4 2395 * muxer for VFR content in fragmenting mode. 2396 * 2397 * @param s media file handle 2398 * @param pkt The packet containing the data to be written. 2399 * <br> 2400 * If the packet is reference-counted, this function will take 2401 * ownership of this reference and unreference it later when it sees 2402 * fit. If the packet is not reference-counted, libavformat will 2403 * make a copy. 2404 * The returned packet will be blank (as if returned from 2405 * av_packet_alloc()), even on error. 2406 * <br> 2407 * This parameter can be NULL (at any time, not just at the end), to 2408 * flush the interleaving queues. 2409 * <br> 2410 * Packet's @ref AVPacket.stream_index "stream_index" field must be 2411 * set to the index of the corresponding stream in @ref 2412 * AVFormatContext.streams "s->streams". 2413 * <br> 2414 * The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts") 2415 * must be set to correct values in the stream's timebase (unless the 2416 * output format is flagged with the AVFMT_NOTIMESTAMPS flag, then 2417 * they can be set to AV_NOPTS_VALUE). 2418 * The dts for subsequent packets in one stream must be strictly 2419 * increasing (unless the output format is flagged with the 2420 * AVFMT_TS_NONSTRICT, then they merely have to be nondecreasing). 2421 * @ref AVPacket.duration "duration" should also be set if known. 2422 * 2423 * @return 0 on success, a negative AVERROR on error. 2424 * 2425 * @see av_write_frame(), AVFormatContext.max_interleave_delta 2426 */ 2427 int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt); 2428 2429 /** 2430 * Write an uncoded frame to an output media file. 2431 * 2432 * The frame must be correctly interleaved according to the container 2433 * specification; if not, av_interleaved_write_uncoded_frame() must be used. 2434 * 2435 * See av_interleaved_write_uncoded_frame() for details. 2436 */ 2437 int av_write_uncoded_frame(AVFormatContext *s, int stream_index, 2438 AVFrame *frame); 2439 2440 /** 2441 * Write an uncoded frame to an output media file. 2442 * 2443 * If the muxer supports it, this function makes it possible to write an AVFrame 2444 * structure directly, without encoding it into a packet. 2445 * It is mostly useful for devices and similar special muxers that use raw 2446 * video or PCM data and will not serialize it into a byte stream. 2447 * 2448 * To test whether it is possible to use it with a given muxer and stream, 2449 * use av_write_uncoded_frame_query(). 2450 * 2451 * The caller gives up ownership of the frame and must not access it 2452 * afterwards. 2453 * 2454 * @return >=0 for success, a negative code on error 2455 */ 2456 int av_interleaved_write_uncoded_frame(AVFormatContext *s, int stream_index, 2457 AVFrame *frame); 2458 2459 /** 2460 * Test whether a muxer supports uncoded frame. 2461 * 2462 * @return >=0 if an uncoded frame can be written to that muxer and stream, 2463 * <0 if not 2464 */ 2465 int av_write_uncoded_frame_query(AVFormatContext *s, int stream_index); 2466 2467 /** 2468 * Write the stream trailer to an output media file and free the 2469 * file private data. 2470 * 2471 * May only be called after a successful call to avformat_write_header. 2472 * 2473 * @param s media file handle 2474 * @return 0 if OK, AVERROR_xxx on error 2475 */ 2476 int av_write_trailer(AVFormatContext *s); 2477 2478 /** 2479 * Return the output format in the list of registered output formats 2480 * which best matches the provided parameters, or return NULL if 2481 * there is no match. 2482 * 2483 * @param short_name if non-NULL checks if short_name matches with the 2484 * names of the registered formats 2485 * @param filename if non-NULL checks if filename terminates with the 2486 * extensions of the registered formats 2487 * @param mime_type if non-NULL checks if mime_type matches with the 2488 * MIME type of the registered formats 2489 */ 2490 const AVOutputFormat *av_guess_format(const char *short_name, 2491 const char *filename, 2492 const char *mime_type); 2493 2494 /** 2495 * Guess the codec ID based upon muxer and filename. 2496 */ 2497 enum AVCodecID av_guess_codec(const AVOutputFormat *fmt, const char *short_name, 2498 const char *filename, const char *mime_type, 2499 enum AVMediaType type); 2500 2501 /** 2502 * Get timing information for the data currently output. 2503 * The exact meaning of "currently output" depends on the format. 2504 * It is mostly relevant for devices that have an internal buffer and/or 2505 * work in real time. 2506 * @param s media file handle 2507 * @param stream stream in the media file 2508 * @param[out] dts DTS of the last packet output for the stream, in stream 2509 * time_base units 2510 * @param[out] wall absolute time when that packet whas output, 2511 * in microsecond 2512 * @return 0 if OK, AVERROR(ENOSYS) if the format does not support it 2513 * Note: some formats or devices may not allow to measure dts and wall 2514 * atomically. 2515 */ 2516 int av_get_output_timestamp(struct AVFormatContext *s, int stream, 2517 int64_t *dts, int64_t *wall); 2518 2519 2520 /** 2521 * @} 2522 */ 2523 2524 2525 /** 2526 * @defgroup lavf_misc Utility functions 2527 * @ingroup libavf 2528 * @{ 2529 * 2530 * Miscellaneous utility functions related to both muxing and demuxing 2531 * (or neither). 2532 */ 2533 2534 /** 2535 * Send a nice hexadecimal dump of a buffer to the specified file stream. 2536 * 2537 * @param f The file stream pointer where the dump should be sent to. 2538 * @param buf buffer 2539 * @param size buffer size 2540 * 2541 * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2 2542 */ 2543 void av_hex_dump(FILE *f, const uint8_t *buf, int size); 2544 2545 /** 2546 * Send a nice hexadecimal dump of a buffer to the log. 2547 * 2548 * @param avcl A pointer to an arbitrary struct of which the first field is a 2549 * pointer to an AVClass struct. 2550 * @param level The importance level of the message, lower values signifying 2551 * higher importance. 2552 * @param buf buffer 2553 * @param size buffer size 2554 * 2555 * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2 2556 */ 2557 void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size); 2558 2559 /** 2560 * Send a nice dump of a packet to the specified file stream. 2561 * 2562 * @param f The file stream pointer where the dump should be sent to. 2563 * @param pkt packet to dump 2564 * @param dump_payload True if the payload must be displayed, too. 2565 * @param st AVStream that the packet belongs to 2566 */ 2567 void av_pkt_dump2(FILE *f, const AVPacket *pkt, int dump_payload, const AVStream *st); 2568 2569 2570 /** 2571 * Send a nice dump of a packet to the log. 2572 * 2573 * @param avcl A pointer to an arbitrary struct of which the first field is a 2574 * pointer to an AVClass struct. 2575 * @param level The importance level of the message, lower values signifying 2576 * higher importance. 2577 * @param pkt packet to dump 2578 * @param dump_payload True if the payload must be displayed, too. 2579 * @param st AVStream that the packet belongs to 2580 */ 2581 void av_pkt_dump_log2(void *avcl, int level, const AVPacket *pkt, int dump_payload, 2582 const AVStream *st); 2583 2584 /** 2585 * Get the AVCodecID for the given codec tag tag. 2586 * If no codec id is found returns AV_CODEC_ID_NONE. 2587 * 2588 * @param tags list of supported codec_id-codec_tag pairs, as stored 2589 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag 2590 * @param tag codec tag to match to a codec ID 2591 */ 2592 enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag); 2593 2594 /** 2595 * Get the codec tag for the given codec id id. 2596 * If no codec tag is found returns 0. 2597 * 2598 * @param tags list of supported codec_id-codec_tag pairs, as stored 2599 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag 2600 * @param id codec ID to match to a codec tag 2601 */ 2602 unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id); 2603 2604 /** 2605 * Get the codec tag for the given codec id. 2606 * 2607 * @param tags list of supported codec_id - codec_tag pairs, as stored 2608 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag 2609 * @param id codec id that should be searched for in the list 2610 * @param tag A pointer to the found tag 2611 * @return 0 if id was not found in tags, > 0 if it was found 2612 */ 2613 int av_codec_get_tag2(const struct AVCodecTag * const *tags, enum AVCodecID id, 2614 unsigned int *tag); 2615 2616 int av_find_default_stream_index(AVFormatContext *s); 2617 2618 /** 2619 * Get the index for a specific timestamp. 2620 * 2621 * @param st stream that the timestamp belongs to 2622 * @param timestamp timestamp to retrieve the index for 2623 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond 2624 * to the timestamp which is <= the requested one, if backward 2625 * is 0, then it will be >= 2626 * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise 2627 * @return < 0 if no such timestamp could be found 2628 */ 2629 int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags); 2630 2631 /** 2632 * Get the index entry count for the given AVStream. 2633 * 2634 * @param st stream 2635 * @return the number of index entries in the stream 2636 */ 2637 int avformat_index_get_entries_count(const AVStream *st); 2638 2639 /** 2640 * Get the AVIndexEntry corresponding to the given index. 2641 * 2642 * @param st Stream containing the requested AVIndexEntry. 2643 * @param idx The desired index. 2644 * @return A pointer to the requested AVIndexEntry if it exists, NULL otherwise. 2645 * 2646 * @note The pointer returned by this function is only guaranteed to be valid 2647 * until any function that takes the stream or the parent AVFormatContext 2648 * as input argument is called. 2649 */ 2650 const AVIndexEntry *avformat_index_get_entry(AVStream *st, int idx); 2651 2652 /** 2653 * Get the AVIndexEntry corresponding to the given timestamp. 2654 * 2655 * @param st Stream containing the requested AVIndexEntry. 2656 * @param timestamp Timestamp to retrieve the index entry for. 2657 * @param flags If AVSEEK_FLAG_BACKWARD then the returned entry will correspond 2658 * to the timestamp which is <= the requested one, if backward 2659 * is 0, then it will be >= 2660 * if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise. 2661 * @return A pointer to the requested AVIndexEntry if it exists, NULL otherwise. 2662 * 2663 * @note The pointer returned by this function is only guaranteed to be valid 2664 * until any function that takes the stream or the parent AVFormatContext 2665 * as input argument is called. 2666 */ 2667 const AVIndexEntry *avformat_index_get_entry_from_timestamp(AVStream *st, 2668 int64_t wanted_timestamp, 2669 int flags); 2670 /** 2671 * Add an index entry into a sorted list. Update the entry if the list 2672 * already contains it. 2673 * 2674 * @param timestamp timestamp in the time base of the given stream 2675 */ 2676 int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp, 2677 int size, int distance, int flags); 2678 2679 2680 /** 2681 * Split a URL string into components. 2682 * 2683 * The pointers to buffers for storing individual components may be null, 2684 * in order to ignore that component. Buffers for components not found are 2685 * set to empty strings. If the port is not found, it is set to a negative 2686 * value. 2687 * 2688 * @param proto the buffer for the protocol 2689 * @param proto_size the size of the proto buffer 2690 * @param authorization the buffer for the authorization 2691 * @param authorization_size the size of the authorization buffer 2692 * @param hostname the buffer for the host name 2693 * @param hostname_size the size of the hostname buffer 2694 * @param port_ptr a pointer to store the port number in 2695 * @param path the buffer for the path 2696 * @param path_size the size of the path buffer 2697 * @param url the URL to split 2698 */ 2699 void av_url_split(char *proto, int proto_size, 2700 char *authorization, int authorization_size, 2701 char *hostname, int hostname_size, 2702 int *port_ptr, 2703 char *path, int path_size, 2704 const char *url); 2705 2706 2707 /** 2708 * Print detailed information about the input or output format, such as 2709 * duration, bitrate, streams, container, programs, metadata, side data, 2710 * codec and time base. 2711 * 2712 * @param ic the context to analyze 2713 * @param index index of the stream to dump information about 2714 * @param url the URL to print, such as source or destination file 2715 * @param is_output Select whether the specified context is an input(0) or output(1) 2716 */ 2717 void av_dump_format(AVFormatContext *ic, 2718 int index, 2719 const char *url, 2720 int is_output); 2721 2722 2723 #define AV_FRAME_FILENAME_FLAGS_MULTIPLE 1 ///< Allow multiple %d 2724 2725 /** 2726 * Return in 'buf' the path with '%d' replaced by a number. 2727 * 2728 * Also handles the '%0nd' format where 'n' is the total number 2729 * of digits and '%%'. 2730 * 2731 * @param buf destination buffer 2732 * @param buf_size destination buffer size 2733 * @param path numbered sequence string 2734 * @param number frame number 2735 * @param flags AV_FRAME_FILENAME_FLAGS_* 2736 * @return 0 if OK, -1 on format error 2737 */ 2738 int av_get_frame_filename2(char *buf, int buf_size, 2739 const char *path, int number, int flags); 2740 2741 int av_get_frame_filename(char *buf, int buf_size, 2742 const char *path, int number); 2743 2744 /** 2745 * Check whether filename actually is a numbered sequence generator. 2746 * 2747 * @param filename possible numbered sequence string 2748 * @return 1 if a valid numbered sequence string, 0 otherwise 2749 */ 2750 int av_filename_number_test(const char *filename); 2751 2752 /** 2753 * Generate an SDP for an RTP session. 2754 * 2755 * Note, this overwrites the id values of AVStreams in the muxer contexts 2756 * for getting unique dynamic payload types. 2757 * 2758 * @param ac array of AVFormatContexts describing the RTP streams. If the 2759 * array is composed by only one context, such context can contain 2760 * multiple AVStreams (one AVStream per RTP stream). Otherwise, 2761 * all the contexts in the array (an AVCodecContext per RTP stream) 2762 * must contain only one AVStream. 2763 * @param n_files number of AVCodecContexts contained in ac 2764 * @param buf buffer where the SDP will be stored (must be allocated by 2765 * the caller) 2766 * @param size the size of the buffer 2767 * @return 0 if OK, AVERROR_xxx on error 2768 */ 2769 int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size); 2770 2771 /** 2772 * Return a positive value if the given filename has one of the given 2773 * extensions, 0 otherwise. 2774 * 2775 * @param filename file name to check against the given extensions 2776 * @param extensions a comma-separated list of filename extensions 2777 */ 2778 int av_match_ext(const char *filename, const char *extensions); 2779 2780 /** 2781 * Test if the given container can store a codec. 2782 * 2783 * @param ofmt container to check for compatibility 2784 * @param codec_id codec to potentially store in container 2785 * @param std_compliance standards compliance level, one of FF_COMPLIANCE_* 2786 * 2787 * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot. 2788 * A negative number if this information is not available. 2789 */ 2790 int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id, 2791 int std_compliance); 2792 2793 /** 2794 * @defgroup riff_fourcc RIFF FourCCs 2795 * @{ 2796 * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are 2797 * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the 2798 * following code: 2799 * @code 2800 * uint32_t tag = MKTAG('H', '2', '6', '4'); 2801 * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 }; 2802 * enum AVCodecID id = av_codec_get_id(table, tag); 2803 * @endcode 2804 */ 2805 /** 2806 * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID. 2807 */ 2808 const struct AVCodecTag *avformat_get_riff_video_tags(void); 2809 /** 2810 * @return the table mapping RIFF FourCCs for audio to AVCodecID. 2811 */ 2812 const struct AVCodecTag *avformat_get_riff_audio_tags(void); 2813 /** 2814 * @return the table mapping MOV FourCCs for video to libavcodec AVCodecID. 2815 */ 2816 const struct AVCodecTag *avformat_get_mov_video_tags(void); 2817 /** 2818 * @return the table mapping MOV FourCCs for audio to AVCodecID. 2819 */ 2820 const struct AVCodecTag *avformat_get_mov_audio_tags(void); 2821 2822 /** 2823 * @} 2824 */ 2825 2826 /** 2827 * Guess the sample aspect ratio of a frame, based on both the stream and the 2828 * frame aspect ratio. 2829 * 2830 * Since the frame aspect ratio is set by the codec but the stream aspect ratio 2831 * is set by the demuxer, these two may not be equal. This function tries to 2832 * return the value that you should use if you would like to display the frame. 2833 * 2834 * Basic logic is to use the stream aspect ratio if it is set to something sane 2835 * otherwise use the frame aspect ratio. This way a container setting, which is 2836 * usually easy to modify can override the coded value in the frames. 2837 * 2838 * @param format the format context which the stream is part of 2839 * @param stream the stream which the frame is part of 2840 * @param frame the frame with the aspect ratio to be determined 2841 * @return the guessed (valid) sample_aspect_ratio, 0/1 if no idea 2842 */ 2843 AVRational av_guess_sample_aspect_ratio(AVFormatContext *format, AVStream *stream, AVFrame *frame); 2844 2845 /** 2846 * Guess the frame rate, based on both the container and codec information. 2847 * 2848 * @param ctx the format context which the stream is part of 2849 * @param stream the stream which the frame is part of 2850 * @param frame the frame for which the frame rate should be determined, may be NULL 2851 * @return the guessed (valid) frame rate, 0/1 if no idea 2852 */ 2853 AVRational av_guess_frame_rate(AVFormatContext *ctx, AVStream *stream, AVFrame *frame); 2854 2855 /** 2856 * Check if the stream st contained in s is matched by the stream specifier 2857 * spec. 2858 * 2859 * See the "stream specifiers" chapter in the documentation for the syntax 2860 * of spec. 2861 * 2862 * @return >0 if st is matched by spec; 2863 * 0 if st is not matched by spec; 2864 * AVERROR code if spec is invalid 2865 * 2866 * @note A stream specifier can match several streams in the format. 2867 */ 2868 int avformat_match_stream_specifier(AVFormatContext *s, AVStream *st, 2869 const char *spec); 2870 2871 int avformat_queue_attached_pictures(AVFormatContext *s); 2872 2873 enum AVTimebaseSource { 2874 AVFMT_TBCF_AUTO = -1, 2875 AVFMT_TBCF_DECODER, 2876 AVFMT_TBCF_DEMUXER, 2877 #if FF_API_R_FRAME_RATE 2878 AVFMT_TBCF_R_FRAMERATE, 2879 #endif 2880 }; 2881 2882 /** 2883 * Transfer internal timing information from one stream to another. 2884 * 2885 * This function is useful when doing stream copy. 2886 * 2887 * @param ofmt target output format for ost 2888 * @param ost output stream which needs timings copy and adjustments 2889 * @param ist reference input stream to copy timings from 2890 * @param copy_tb define from where the stream codec timebase needs to be imported 2891 */ 2892 int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt, 2893 AVStream *ost, const AVStream *ist, 2894 enum AVTimebaseSource copy_tb); 2895 2896 /** 2897 * Get the internal codec timebase from a stream. 2898 * 2899 * @param st input stream to extract the timebase from 2900 */ 2901 AVRational av_stream_get_codec_timebase(const AVStream *st); 2902 2903 /** 2904 * @} 2905 */ 2906 2907 #endif /* AVFORMAT_AVFORMAT_H */ 2908