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/*
 * copyright (c) 2001 Fabrice Bellard
 *
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 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

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#ifndef AVFORMAT_AVFORMAT_H
#define AVFORMAT_AVFORMAT_H
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/**
 * @file
 * @ingroup libavf
 * Main libavformat public API header
 */

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/**
 * @defgroup libavf I/O and Muxing/Demuxing Library
 * @{
 *
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 * Libavformat (lavf) is a library for dealing with various media container
 * formats. Its main two purposes are demuxing - i.e. splitting a media file
 * into component streams, and the reverse process of muxing - writing supplied
 * data in a specified container format. It also has an @ref lavf_io
 * "I/O module" which supports a number of protocols for accessing the data (e.g.
 * file, tcp, http and others). Before using lavf, you need to call
 * av_register_all() to register all compiled muxers, demuxers and protocols.
 * Unless you are absolutely sure you won't use libavformat's network
 * capabilities, you should also call avformat_network_init().
 *
 * A supported input format is described by an AVInputFormat struct, conversely
 * an output format is described by AVOutputFormat. You can iterate over all
 * registered input/output formats using the av_iformat_next() /
 * av_oformat_next() functions. The protocols layer is not part of the public
 * API, so you can only get the names of supported protocols with the
 * avio_enum_protocols() function.
 *
 * Main lavf structure used for both muxing and demuxing is AVFormatContext,
 * which exports all information about the file being read or written. As with
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 * most Libavformat structures, its size is not part of public ABI, so it cannot be
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 * allocated on stack or directly with av_malloc(). To create an
 * AVFormatContext, use avformat_alloc_context() (some functions, like
 * avformat_open_input() might do that for you).
 *
 * Most importantly an AVFormatContext contains:
 * @li the @ref AVFormatContext.iformat "input" or @ref AVFormatContext.oformat
 * "output" format. It is either autodetected or set by user for input;
 * always set by user for output.
 * @li an @ref AVFormatContext.streams "array" of AVStreams, which describe all
 * elementary streams stored in the file. AVStreams are typically referred to
 * using their index in this array.
 * @li an @ref AVFormatContext.pb "I/O context". It is either opened by lavf or
 * set by user for input, always set by user for output (unless you are dealing
 * with an AVFMT_NOFILE format).
 *
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 * @section lavf_options Passing options to (de)muxers
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 * It is possible to configure lavf muxers and demuxers using the @ref avoptions
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 * mechanism. Generic (format-independent) libavformat options are provided by
 * AVFormatContext, they can be examined from a user program by calling
 * av_opt_next() / av_opt_find() on an allocated AVFormatContext (or its AVClass
 * from avformat_get_class()). Private (format-specific) options are provided by
 * AVFormatContext.priv_data if and only if AVInputFormat.priv_class /
 * AVOutputFormat.priv_class of the corresponding format struct is non-NULL.
 * Further options may be provided by the @ref AVFormatContext.pb "I/O context",
 * if its AVClass is non-NULL, and the protocols layer. See the discussion on
 * nesting in @ref avoptions documentation to learn how to access those.
 *
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 * @defgroup lavf_decoding Demuxing
 * @{
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 * Demuxers read a media file and split it into chunks of data (@em packets). A
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 * @ref AVPacket "packet" contains one or more encoded frames which belongs to a
 * single elementary stream. In the lavf API this process is represented by the
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 * avformat_open_input() function for opening a file, av_read_frame() for
 * reading a single packet and finally avformat_close_input(), which does the
 * cleanup.
 *
 * @section lavf_decoding_open Opening a media file
 * The minimum information required to open a file is its URL or filename, which
 * is passed to avformat_open_input(), as in the following code:
 * @code
 * const char    *url = "in.mp3";
 * AVFormatContext *s = NULL;
 * int ret = avformat_open_input(&s, url, NULL, NULL);
 * if (ret < 0)
 *     abort();
 * @endcode
 * The above code attempts to allocate an AVFormatContext, open the
 * specified file (autodetecting the format) and read the header, exporting the
 * information stored there into s. Some formats do not have a header or do not
 * store enough information there, so it is recommended that you call the
 * avformat_find_stream_info() function which tries to read and decode a few
 * frames to find missing information.
 *
 * In some cases you might want to preallocate an AVFormatContext yourself with
 * avformat_alloc_context() and do some tweaking on it before passing it to
 * avformat_open_input(). One such case is when you want to use custom functions
 * for reading input data instead of lavf internal I/O layer.
 * To do that, create your own AVIOContext with avio_alloc_context(), passing
 * your reading callbacks to it. Then set the @em pb field of your
 * AVFormatContext to newly created AVIOContext.
 *
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 * Since the format of the opened file is in general not known until after
 * avformat_open_input() has returned, it is not possible to set demuxer private
 * options on a preallocated context. Instead, the options should be passed to
 * avformat_open_input() wrapped in an AVDictionary:
 * @code
 * AVDictionary *options = NULL;
 * av_dict_set(&options, "video_size", "640x480", 0);
 * av_dict_set(&options, "pixel_format", "rgb24", 0);
 *
 * if (avformat_open_input(&s, url, NULL, &options) < 0)
 *     abort();
 * av_dict_free(&options);
 * @endcode
 * This code passes the private options 'video_size' and 'pixel_format' to the
 * demuxer. They would be necessary for e.g. the rawvideo demuxer, since it
 * cannot know how to interpret raw video data otherwise. If the format turns
 * out to be something different than raw video, those options will not be
 * recognized by the demuxer and therefore will not be applied. Such unrecognized
 * options are then returned in the options dictionary (recognized options are
 * consumed). The calling program can handle such unrecognized options as it
 * wishes, e.g.
 * @code
 * AVDictionaryEntry *e;
 * if (e = av_dict_get(options, "", NULL, AV_DICT_IGNORE_SUFFIX)) {
 *     fprintf(stderr, "Option %s not recognized by the demuxer.\n", e->key);
 *     abort();
 * }
 * @endcode
 *
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 * After you have finished reading the file, you must close it with
 * avformat_close_input(). It will free everything associated with the file.
 *
 * @section lavf_decoding_read Reading from an opened file
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 * Reading data from an opened AVFormatContext is done by repeatedly calling
 * av_read_frame() on it. Each call, if successful, will return an AVPacket
 * containing encoded data for one AVStream, identified by
 * AVPacket.stream_index. This packet may be passed straight into the libavcodec
 * decoding functions avcodec_decode_video2(), avcodec_decode_audio4() or
 * avcodec_decode_subtitle2() if the caller wishes to decode the data.
 *
 * AVPacket.pts, AVPacket.dts and AVPacket.duration timing information will be
 * set if known. They may also be unset (i.e. AV_NOPTS_VALUE for
 * pts/dts, 0 for duration) if the stream does not provide them. The timing
 * information will be in AVStream.time_base units, i.e. it has to be
 * multiplied by the timebase to convert them to seconds.
 *
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 * If AVPacket.buf is set on the returned packet, then the packet is
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 * allocated dynamically and the user may keep it indefinitely.
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 * Otherwise, if AVPacket.buf is NULL, the packet data is backed by a
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 * static storage somewhere inside the demuxer and the packet is only valid
 * until the next av_read_frame() call or closing the file. If the caller
 * requires a longer lifetime, av_dup_packet() will make an av_malloc()ed copy
 * of it.
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 * In both cases, the packet must be freed with av_packet_unref() when it is no
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 * longer needed.
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 *
 * @section lavf_decoding_seek Seeking
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 * @}
 *
 * @defgroup lavf_encoding Muxing
 * @{
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 * Muxers take encoded data in the form of @ref AVPacket "AVPackets" and write
 * it into files or other output bytestreams in the specified container format.
 *
 * The main API functions for muxing are avformat_write_header() for writing the
 * file header, av_write_frame() / av_interleaved_write_frame() for writing the
 * packets and av_write_trailer() for finalizing the file.
 *
 * At the beginning of the muxing process, the caller must first call
 * avformat_alloc_context() to create a muxing context. The caller then sets up
 * the muxer by filling the various fields in this context:
 *
 * - The @ref AVFormatContext.oformat "oformat" field must be set to select the
 *   muxer that will be used.
 * - Unless the format is of the AVFMT_NOFILE type, the @ref AVFormatContext.pb
 *   "pb" field must be set to an opened IO context, either returned from
 *   avio_open2() or a custom one.
 * - Unless the format is of the AVFMT_NOSTREAMS type, at least one stream must
 *   be created with the avformat_new_stream() function. The caller should fill
 *   the @ref AVStream.codec "stream codec context" information, such as the
 *   codec @ref AVCodecContext.codec_type "type", @ref AVCodecContext.codec_id
 *   "id" and other parameters (e.g. width / height, the pixel or sample format,
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 *   etc.) as known. The @ref AVStream.time_base "stream timebase" should
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 *   be set to the timebase that the caller desires to use for this stream (note
 *   that the timebase actually used by the muxer can be different, as will be
 *   described later).
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 * - It is advised to manually initialize only the relevant fields in
 *   AVCodecContext, rather than using @ref avcodec_copy_context() during
 *   remuxing: there is no guarantee that the codec context values remain valid
 *   for both input and output format contexts.
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 * - The caller may fill in additional information, such as @ref
 *   AVFormatContext.metadata "global" or @ref AVStream.metadata "per-stream"
 *   metadata, @ref AVFormatContext.chapters "chapters", @ref
 *   AVFormatContext.programs "programs", etc. as described in the
 *   AVFormatContext documentation. Whether such information will actually be
 *   stored in the output depends on what the container format and the muxer
 *   support.
 *
 * When the muxing context is fully set up, the caller must call
 * avformat_write_header() to initialize the muxer internals and write the file
 * header. Whether anything actually is written to the IO context at this step
 * depends on the muxer, but this function must always be called. Any muxer
 * private options must be passed in the options parameter to this function.
 *
 * The data is then sent to the muxer by repeatedly calling av_write_frame() or
 * av_interleaved_write_frame() (consult those functions' documentation for
 * discussion on the difference between them; only one of them may be used with
 * a single muxing context, they should not be mixed). Do note that the timing
 * information on the packets sent to the muxer must be in the corresponding
 * AVStream's timebase. That timebase is set by the muxer (in the
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 * avformat_write_header() step) and may be different from the timebase
 * requested by the caller.
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 *
 * Once all the data has been written, the caller must call av_write_trailer()
 * to flush any buffered packets and finalize the output file, then close the IO
 * context (if any) and finally free the muxing context with
 * avformat_free_context().
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 * @}
 *
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 * @defgroup lavf_io I/O Read/Write
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 * @{
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 * @section lavf_io_dirlist Directory listing
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 * The directory listing API makes it possible to list files on remote servers.
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 *
 * Some of possible use cases:
 * - an "open file" dialog to choose files from a remote location,
 * - a recursive media finder providing a player with an ability to play all
 * files from a given directory.
 *
 * @subsection lavf_io_dirlist_open Opening a directory
 * At first, a directory needs to be opened by calling avio_open_dir()
 * supplied with a URL and, optionally, ::AVDictionary containing
 * protocol-specific parameters. The function returns zero or positive
 * integer and allocates AVIODirContext on success.
 *
 * @code
 * AVIODirContext *ctx = NULL;
 * if (avio_open_dir(&ctx, "smb://example.com/some_dir", NULL) < 0) {
 *     fprintf(stderr, "Cannot open directory.\n");
 *     abort();
 * }
 * @endcode
 *
 * This code tries to open a sample directory using smb protocol without
 * any additional parameters.
 *
 * @subsection lavf_io_dirlist_read Reading entries
 * Each directory's entry (i.e. file, another directory, anything else
 * within ::AVIODirEntryType) is represented by AVIODirEntry.
 * Reading consecutive entries from an opened AVIODirContext is done by
 * repeatedly calling avio_read_dir() on it. Each call returns zero or
 * positive integer if successful. Reading can be stopped right after the
 * NULL entry has been read -- it means there are no entries left to be
 * read. The following code reads all entries from a directory associated
 * with ctx and prints their names to standard output.
 * @code
 * AVIODirEntry *entry = NULL;
 * for (;;) {
 *     if (avio_read_dir(ctx, &entry) < 0) {
 *         fprintf(stderr, "Cannot list directory.\n");
 *         abort();
 *     }
 *     if (!entry)
 *         break;
 *     printf("%s\n", entry->name);
 *     avio_free_directory_entry(&entry);
 * }
 * @endcode
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 * @}
 *
 * @defgroup lavf_codec Demuxers
 * @{
 * @defgroup lavf_codec_native Native Demuxers
 * @{
 * @}
 * @defgroup lavf_codec_wrappers External library wrappers
 * @{
 * @}
 * @}
 * @defgroup lavf_protos I/O Protocols
 * @{
 * @}
 * @defgroup lavf_internal Internal
 * @{
 * @}
 * @}
 *
 */
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#include <time.h>
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#include <stdio.h>  /* FILE */
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#include "libavcodec/avcodec.h"
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#include "libavutil/dict.h"
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#include "libavutil/log.h"
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#include "avio.h"
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#include "libavformat/version.h"
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struct AVFormatContext;

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struct AVDeviceInfoList;
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struct AVDeviceCapabilitiesQuery;
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/**
 * @defgroup metadata_api Public Metadata API
 * @{
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 * @ingroup libavf
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 * The metadata API allows libavformat to export metadata tags to a client
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 * application when demuxing. Conversely it allows a client application to
 * set metadata when muxing.
 *
 * Metadata is exported or set as pairs of key/value strings in the 'metadata'
 * fields of the AVFormatContext, AVStream, AVChapter and AVProgram structs
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 * using the @ref lavu_dict "AVDictionary" API. Like all strings in FFmpeg,
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 * metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
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 * exported by demuxers isn't checked to be valid UTF-8 in most cases.
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 *
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 * Important concepts to keep in mind:
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 * -  Keys are unique; there can never be 2 tags with the same key. This is
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 *    also meant semantically, i.e., a demuxer should not knowingly produce
 *    several keys that are literally different but semantically identical.
 *    E.g., key=Author5, key=Author6. In this example, all authors must be
 *    placed in the same tag.
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 * -  Metadata is flat, not hierarchical; there are no subtags. If you
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 *    want to store, e.g., the email address of the child of producer Alice
 *    and actor Bob, that could have key=alice_and_bobs_childs_email_address.
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 * -  Several modifiers can be applied to the tag name. This is done by
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 *    appending a dash character ('-') and the modifier name in the order
 *    they appear in the list below -- e.g. foo-eng-sort, not foo-sort-eng.
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 *    -  language -- a tag whose value is localized for a particular language
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 *       is appended with the ISO 639-2/B 3-letter language code.
 *       For example: Author-ger=Michael, Author-eng=Mike
 *       The original/default language is in the unqualified "Author" tag.
 *       A demuxer should set a default if it sets any translated tag.
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 *    -  sorting  -- a modified version of a tag that should be used for
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 *       sorting will have '-sort' appended. E.g. artist="The Beatles",
 *       artist-sort="Beatles, The".
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 * - Some protocols and demuxers support metadata updates. After a successful
 *   call to av_read_packet(), AVFormatContext.event_flags or AVStream.event_flags
 *   will be updated to indicate if metadata changed. In order to detect metadata
 *   changes on a stream, you need to loop through all streams in the AVFormatContext
 *   and check their individual event_flags.
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 *
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 * -  Demuxers attempt to export metadata in a generic format, however tags
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 *    with no generic equivalents are left as they are stored in the container.
 *    Follows a list of generic tag names:
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 *
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 @verbatim
 album        -- name of the set this work belongs to
 album_artist -- main creator of the set/album, if different from artist.
                 e.g. "Various Artists" for compilation albums.
 artist       -- main creator of the work
 comment      -- any additional description of the file.
 composer     -- who composed the work, if different from artist.
 copyright    -- name of copyright holder.
 creation_time-- date when the file was created, preferably in ISO 8601.
 date         -- date when the work was created, preferably in ISO 8601.
 disc         -- number of a subset, e.g. disc in a multi-disc collection.
 encoder      -- name/settings of the software/hardware that produced the file.
 encoded_by   -- person/group who created the file.
 filename     -- original name of the file.
 genre        -- <self-evident>.
 language     -- main language in which the work is performed, preferably
                 in ISO 639-2 format. Multiple languages can be specified by
                 separating them with commas.
 performer    -- artist who performed the work, if different from artist.
                 E.g for "Also sprach Zarathustra", artist would be "Richard
                 Strauss" and performer "London Philharmonic Orchestra".
 publisher    -- name of the label/publisher.
 service_name     -- name of the service in broadcasting (channel name).
 service_provider -- name of the service provider in broadcasting.
 title        -- name of the work.
 track        -- number of this work in the set, can be in form current/total.
 variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
 @endverbatim
 *
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 * Look in the examples section for an application example how to use the Metadata API.
 *
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 * @}
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 */

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/* packet functions */

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/**
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 * Allocate and read the payload of a packet and initialize its
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 * fields with default values.
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 *
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 * @param s    associated IO context
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 * @param pkt packet
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 * @param size desired payload size
 * @return >0 (read size) if OK, AVERROR_xxx otherwise
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 */
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int av_get_packet(AVIOContext *s, AVPacket *pkt, int size);
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/**
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 * Read data and append it to the current content of the AVPacket.
 * If pkt->size is 0 this is identical to av_get_packet.
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 * Note that this uses av_grow_packet and thus involves a realloc
 * which is inefficient. Thus this function should only be used
 * when there is no reasonable way to know (an upper bound of)
 * the final size.
 *
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 * @param s    associated IO context
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 * @param pkt packet
 * @param size amount of data to read
 * @return >0 (read size) if OK, AVERROR_xxx otherwise, previous data
 *         will not be lost even if an error occurs.
 */
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int av_append_packet(AVIOContext *s, AVPacket *pkt, int size);
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#if FF_API_LAVF_FRAC
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/*************************************************/
/* fractional numbers for exact pts handling */

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/**
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 * The exact value of the fractional number is: 'val + num / den'.
 * num is assumed to be 0 <= num < den.
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 */
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typedef struct AVFrac {
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    int64_t val, num, den;
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} AVFrac;
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#endif
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/*************************************************/
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/* input/output formats */
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struct AVCodecTag;

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/**
 * This structure contains the data a format has to probe a file.
 */
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typedef struct AVProbeData {
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    const char *filename;
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    unsigned char *buf; /**< Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero. */
    int buf_size;       /**< Size of buf except extra allocated bytes */
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    const char *mime_type; /**< mime_type, when known. */
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} AVProbeData;

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#define AVPROBE_SCORE_RETRY (AVPROBE_SCORE_MAX/4)
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#define AVPROBE_SCORE_STREAM_RETRY (AVPROBE_SCORE_MAX/4-1)

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#define AVPROBE_SCORE_EXTENSION  50 ///< score for file extension
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#define AVPROBE_SCORE_MIME       75 ///< score for file mime type
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#define AVPROBE_SCORE_MAX       100 ///< maximum score

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#define AVPROBE_PADDING_SIZE 32             ///< extra allocated bytes at the end of the probe buffer
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/// Demuxer will use avio_open, no opened file should be provided by the caller.
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#define AVFMT_NOFILE        0x0001
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#define AVFMT_NEEDNUMBER    0x0002 /**< Needs '%d' in filename. */
#define AVFMT_SHOW_IDS      0x0008 /**< Show format stream IDs numbers. */
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#if FF_API_LAVF_FMT_RAWPICTURE
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#define AVFMT_RAWPICTURE    0x0020 /**< Format wants AVPicture structure for
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                                      raw picture data. @deprecated Not used anymore */
#endif
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#define AVFMT_GLOBALHEADER  0x0040 /**< Format wants global header. */
#define AVFMT_NOTIMESTAMPS  0x0080 /**< Format does not need / have any timestamps. */
#define AVFMT_GENERIC_INDEX 0x0100 /**< Use generic index building code. */
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#define AVFMT_TS_DISCONT    0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
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#define AVFMT_VARIABLE_FPS  0x0400 /**< Format allows variable fps. */
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#define AVFMT_NODIMENSIONS  0x0800 /**< Format does not need width/height */
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#define AVFMT_NOSTREAMS     0x1000 /**< Format does not require any streams */
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#define AVFMT_NOBINSEARCH   0x2000 /**< Format does not allow to fall back on binary search via read_timestamp */
#define AVFMT_NOGENSEARCH   0x4000 /**< Format does not allow to fall back on generic search */
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#define AVFMT_NO_BYTE_SEEK  0x8000 /**< Format does not allow seeking by bytes */
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#define AVFMT_ALLOW_FLUSH  0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
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#define AVFMT_TS_NONSTRICT 0x20000 /**< Format does not require strictly
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                                        increasing timestamps, but they must
                                        still be monotonic */
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#define AVFMT_TS_NEGATIVE  0x40000 /**< Format allows muxing negative
                                        timestamps. If not set the timestamp
                                        will be shifted in av_write_frame and
                                        av_interleaved_write_frame so they
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                                        start from 0.
                                        The user or muxer can override this through
                                        AVFormatContext.avoid_negative_ts
                                        */
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#define AVFMT_SEEK_TO_PTS   0x4000000 /**< Seeking is based on PTS */
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/**
 * @addtogroup lavf_encoding
 * @{
 */
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typedef struct AVOutputFormat {
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    const char *name;
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    /**
     * Descriptive name for the format, meant to be more human-readable
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     * than name. You should use the NULL_IF_CONFIG_SMALL() macro
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     * to define it.
     */
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    const char *long_name;
    const char *mime_type;
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    const char *extensions; /**< comma-separated filename extensions */
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    /* output support */
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    enum AVCodecID audio_codec;    /**< default audio codec */
    enum AVCodecID video_codec;    /**< default video codec */
    enum AVCodecID subtitle_codec; /**< default subtitle codec */
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    /**
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     * can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER,
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     * AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
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     * AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
     * AVFMT_TS_NONSTRICT
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     */
    int flags;

    /**
     * List of supported codec_id-codec_tag pairs, ordered by "better
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     * choice first". The arrays are all terminated by AV_CODEC_ID_NONE.
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     */
    const struct AVCodecTag * const *codec_tag;


    const AVClass *priv_class; ///< AVClass for the private context

    /*****************************************************************
     * No fields below this line are part of the public API. They
     * may not be used outside of libavformat and can be changed and
     * removed at will.
     * New public fields should be added right above.
     *****************************************************************
     */
    struct AVOutputFormat *next;
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    /**
     * size of private data so that it can be allocated in the wrapper
     */
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    int priv_data_size;
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    int (*write_header)(struct AVFormatContext *);
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    /**
     * Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,
     * pkt can be NULL in order to flush data buffered in the muxer.
     * When flushing, return 0 if there still is more data to flush,
     * or 1 if everything was flushed and there is no more buffered
     * data.
     */
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    int (*write_packet)(struct AVFormatContext *, AVPacket *pkt);
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    int (*write_trailer)(struct AVFormatContext *);
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    /**
     * Currently only used to set pixel format if not YUV420P.
     */
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    int (*interleave_packet)(struct AVFormatContext *, AVPacket *out,
                             AVPacket *in, int flush);
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    /**
     * Test if the given codec can be stored in this container.
     *
     * @return 1 if the codec is supported, 0 if it is not.
     *         A negative number if unknown.
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     *         MKTAG('A', 'P', 'I', 'C') if the codec is only supported as AV_DISPOSITION_ATTACHED_PIC
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     */
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    int (*query_codec)(enum AVCodecID id, int std_compliance);
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    void (*get_output_timestamp)(struct AVFormatContext *s, int stream,
                                 int64_t *dts, int64_t *wall);
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    /**
     * Allows sending messages from application to device.
     */
    int (*control_message)(struct AVFormatContext *s, int type,
                           void *data, size_t data_size);
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    /**
     * Write an uncoded AVFrame.
     *
     * See av_write_uncoded_frame() for details.
     *
     * The library will free *frame afterwards, but the muxer can prevent it
     * by setting the pointer to NULL.
     */
    int (*write_uncoded_frame)(struct AVFormatContext *, int stream_index,
                               AVFrame **frame, unsigned flags);
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    /**
     * Returns device list with it properties.
     * @see avdevice_list_devices() for more details.
     */
    int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list);
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    /**
     * Initialize device capabilities submodule.
     * @see avdevice_capabilities_create() for more details.
     */
    int (*create_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);
    /**
     * Free device capabilities submodule.
     * @see avdevice_capabilities_free() for more details.
     */
    int (*free_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);
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    enum AVCodecID data_codec; /**< default data codec */
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} AVOutputFormat;
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/**
 * @}
 */
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/**
 * @addtogroup lavf_decoding
 * @{
 */
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typedef struct AVInputFormat {
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    /**
     * A comma separated list of short names for the format. New names
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     * may be appended with a minor bump.
     */
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    const char *name;
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    /**
     * Descriptive name for the format, meant to be more human-readable
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     * than name. You should use the NULL_IF_CONFIG_SMALL() macro
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     * to define it.
     */
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    const char *long_name;
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    /**
     * Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
     * AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
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     * AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK, AVFMT_SEEK_TO_PTS.
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     */
    int flags;

    /**
     * If extensions are defined, then no probe is done. You should
     * usually not use extension format guessing because it is not
     * reliable enough
     */
    const char *extensions;

    const struct AVCodecTag * const *codec_tag;

    const AVClass *priv_class; ///< AVClass for the private context

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    /**
     * Comma-separated list of mime types.
     * It is used check for matching mime types while probing.
     * @see av_probe_input_format2
     */
    const char *mime_type;

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    /*****************************************************************
     * No fields below this line are part of the public API. They
     * may not be used outside of libavformat and can be changed and
     * removed at will.
     * New public fields should be added right above.
     *****************************************************************
     */
    struct AVInputFormat *next;

    /**
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     * Raw demuxers store their codec ID here.
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     */
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    int raw_codec_id;
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    /**
     * Size of private data so that it can be allocated in the wrapper.
     */
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    int priv_data_size;
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    /**
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     * Tell if a given file has a chance of being parsed as this format.
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     * The buffer provided is guaranteed to be AVPROBE_PADDING_SIZE bytes
     * big so you do not have to check for that unless you need more.
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     */
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    int (*read_probe)(AVProbeData *);
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    /**
     * Read the format header and initialize the AVFormatContext
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     * structure. Return 0 if OK. 'avformat_new_stream' should be
     * called to create new streams.
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     */
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    int (*read_header)(struct AVFormatContext *);
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    /**
     * Read one packet and put it in 'pkt'. pts and flags are also
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     * set. 'avformat_new_stream' can be called only if the flag
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     * AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
     * background thread).
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     * @return 0 on success, < 0 on error.
     *         When returning an error, pkt must not have been allocated
     *         or must be freed before returning
     */
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    int (*read_packet)(struct AVFormatContext *, AVPacket *pkt);
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    /**
     * Close the stream. The AVFormatContext and AVStreams are not
     * freed by this function
     */
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    int (*read_close)(struct AVFormatContext *);
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    /**
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     * Seek to a given timestamp relative to the frames in
     * stream component stream_index.
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     * @param stream_index Must not be -1.
     * @param flags Selects which direction should be preferred if no exact
     *              match is available.
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     * @return >= 0 on success (but not necessarily the new offset)
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     */
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    int (*read_seek)(struct AVFormatContext *,
                     int stream_index, int64_t timestamp, int flags);

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    /**
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     * Get the next timestamp in stream[stream_index].time_base units.
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     * @return the timestamp or AV_NOPTS_VALUE if an error occurred
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     */
    int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index,
                              int64_t *pos, int64_t pos_limit);
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    /**
     * Start/resume playing - only meaningful if using a network-based format
     * (RTSP).
     */
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    int (*read_play)(struct AVFormatContext *);

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    /**
     * Pause playing - only meaningful if using a network-based format
     * (RTSP).
     */
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    int (*read_pause)(struct AVFormatContext *);

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    /**
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     * Seek to timestamp ts.
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     * Seeking will be done so that the point from which all active streams
     * can be presented successfully will be closest to ts and within min/max_ts.
     * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
     */
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    int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
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    /**
     * Returns device list with it properties.
     * @see avdevice_list_devices() for more details.
     */
    int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list);
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    /**
     * Initialize device capabilities submodule.
     * @see avdevice_capabilities_create() for more details.
     */
    int (*create_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);

    /**
     * Free device capabilities submodule.
     * @see avdevice_capabilities_free() for more details.
     */
    int (*free_device_capabilities)(struct AVFormatContext *s, struct AVDeviceCapabilitiesQuery *caps);
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} AVInputFormat;
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/**
 * @}
 */
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enum AVStreamParseType {
    AVSTREAM_PARSE_NONE,
    AVSTREAM_PARSE_FULL,       /**< full parsing and repack */
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    AVSTREAM_PARSE_HEADERS,    /**< Only parse headers, do not repack. */
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    AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */
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    AVSTREAM_PARSE_FULL_ONCE,  /**< full parsing and repack of the first frame only, only implemented for H.264 currently */
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    AVSTREAM_PARSE_FULL_RAW=MKTAG(0,'R','A','W'),       /**< full parsing and repack with timestamp and position generation by parser for raw
                                                             this assumes that each packet in the file contains no demuxer level headers and
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                                                             just codec level data, otherwise position generation would fail */
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};

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typedef struct AVIndexEntry {
    int64_t pos;
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    int64_t timestamp;        /**<
                               * Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are available
                               * when seeking to this entry. That means preferable PTS on keyframe based formats.
                               * But demuxers can choose to store a different timestamp, if it is more convenient for the implementation or nothing better
                               * is known
                               */
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#define AVINDEX_KEYFRAME 0x0001
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    int flags:2;
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    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).
    int min_distance;         /**< Minimum distance between this and the previous keyframe, used to avoid unneeded searching. */
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} AVIndexEntry;

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#define AV_DISPOSITION_DEFAULT   0x0001
#define AV_DISPOSITION_DUB       0x0002
#define AV_DISPOSITION_ORIGINAL  0x0004
#define AV_DISPOSITION_COMMENT   0x0008
#define AV_DISPOSITION_LYRICS    0x0010
#define AV_DISPOSITION_KARAOKE   0x0020
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/**
 * Track should be used during playback by default.
 * Useful for subtitle track that should be displayed
 * even when user did not explicitly ask for subtitles.
 */
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#define AV_DISPOSITION_FORCED    0x0040
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#define AV_DISPOSITION_HEARING_IMPAIRED  0x0080  /**< stream for hearing impaired audiences */
#define AV_DISPOSITION_VISUAL_IMPAIRED   0x0100  /**< stream for visual impaired audiences */
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#define AV_DISPOSITION_CLEAN_EFFECTS     0x0200  /**< stream without voice */
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/**
 * The stream is stored in the file as an attached picture/"cover art" (e.g.
 * APIC frame in ID3v2). The single packet associated with it will be returned
 * among the first few packets read from the file unless seeking takes place.
 * It can also be accessed at any time in AVStream.attached_pic.
 */
#define AV_DISPOSITION_ATTACHED_PIC      0x0400
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typedef struct AVStreamInternal AVStreamInternal;

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/**
 * To specify text track kind (different from subtitles default).
 */
#define AV_DISPOSITION_CAPTIONS     0x10000
#define AV_DISPOSITION_DESCRIPTIONS 0x20000
#define AV_DISPOSITION_METADATA     0x40000

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/**
 * Options for behavior on timestamp wrap detection.
 */
#define AV_PTS_WRAP_IGNORE      0   ///< ignore the wrap
#define AV_PTS_WRAP_ADD_OFFSET  1   ///< add the format specific offset on wrap detection
#define AV_PTS_WRAP_SUB_OFFSET  -1  ///< subtract the format specific offset on wrap detection

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/**
 * Stream structure.
 * New fields can be added to the end with minor version bumps.
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 * Removal, reordering and changes to existing fields require a major
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 * version bump.
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 * sizeof(AVStream) must not be used outside libav*.
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 */
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typedef struct AVStream {
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    int index;    /**< stream index in AVFormatContext */
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    /**
     * Format-specific stream ID.
     * decoding: set by libavformat
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     * encoding: set by the user, replaced by libavformat if left unset
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     */
    int id;
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    /**
     * Codec context associated with this stream. Allocated and freed by
     * libavformat.
     *
     * - decoding: The demuxer exports codec information stored in the headers
     *             here.
     * - encoding: The user sets codec information, the muxer writes it to the
     *             output. Mandatory fields as specified in AVCodecContext
     *             documentation must be set even if this AVCodecContext is
     *             not actually used for encoding.
     */
    AVCodecContext *codec;
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    void *priv_data;
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#if FF_API_LAVF_FRAC
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    /**
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     * @deprecated this field is unused
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     */
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    attribute_deprecated
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    struct AVFrac pts;
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#endif
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    /**
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     * This is the fundamental unit of time (in seconds) in terms
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     * of which frame timestamps are represented.
     *
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     * decoding: set by libavformat
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     * encoding: May be set by the caller before avformat_write_header() to
     *           provide a hint to the muxer about the desired timebase. In
     *           avformat_write_header(), the muxer will overwrite this field
     *           with the timebase that will actually be used for the timestamps
     *           written into the file (which may or may not be related to the
     *           user-provided one, depending on the format).
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     */
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    AVRational time_base;
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    /**
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     * Decoding: pts of the first frame of the stream in presentation order, in stream time base.
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     * Only set this if you are absolutely 100% sure that the value you set
     * it to really is the pts of the first frame.
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     * This may be undefined (AV_NOPTS_VALUE).
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     * @note The ASF header does NOT contain a correct start_time the ASF
     * demuxer must NOT set this.
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     */
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    int64_t start_time;
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    /**
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     * Decoding: duration of the stream, in stream time base.
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     * If a source file does not specify a duration, but does specify
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     * a bitrate, this value will be estimated from bitrate and file size.
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     */
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    int64_t duration;
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    int64_t nb_frames;                 ///< number of frames in this stream if known or 0
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    int disposition; /**< AV_DISPOSITION_* bit field */
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    enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.

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    /**
     * sample aspect ratio (0 if unknown)
     * - encoding: Set by user.
     * - decoding: Set by libavformat.
     */
    AVRational sample_aspect_ratio;
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    AVDictionary *metadata;
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    /**
     * Average framerate
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     *
     * - demuxing: May be set by libavformat when creating the stream or in
     *             avformat_find_stream_info().
     * - muxing: May be set by the caller before avformat_write_header().
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     */
    AVRational avg_frame_rate;
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    /**
     * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
     * will contain the attached picture.
     *
     * decoding: set by libavformat, must not be modified by the caller.
     * encoding: unused
     */
    AVPacket attached_pic;

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    /**
     * An array of side data that applies to the whole stream (i.e. the
     * container does not allow it to change between packets).
     *
     * There may be no overlap between the side data in this array and side data
     * in the packets. I.e. a given side data is either exported by the muxer
     * (demuxing) / set by the caller (muxing) in this array, then it never
     * appears in the packets, or the side data is exported / sent through
     * the packets (always in the first packet where the value becomes known or
     * changes), then it does not appear in this array.
     *
     * - demuxing: Set by libavformat when the stream is created.
     * - muxing: May be set by the caller before avformat_write_header().
     *
     * Freed by libavformat in avformat_free_context().
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     *
     * @see av_format_inject_global_side_data()
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     */
    AVPacketSideData *side_data;
    /**
     * The number of elements in the AVStream.side_data array.
     */
    int            nb_side_data;

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    /**
     * Flags for the user to detect events happening on the stream. Flags must
     * be cleared by the user once the event has been handled.
     * A combination of AVSTREAM_EVENT_FLAG_*.
     */
    int event_flags;
#define AVSTREAM_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.

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    /*****************************************************************
     * All fields below this line are not part of the public API. They
     * may not be used outside of libavformat and can be changed and
     * removed at will.
     * New public fields should be added right above.
     *****************************************************************
     */

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    /**
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     * Stream information used internally by av_find_stream_info()
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     */
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#define MAX_STD_TIMEBASES (30*12+7+6)
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    struct {
        int64_t last_dts;
        int64_t duration_gcd;
        int duration_count;
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        int64_t rfps_duration_sum;
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        double (*duration_error)[2][MAX_STD_TIMEBASES];
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        int64_t codec_info_duration;
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        int64_t codec_info_duration_fields;
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        /**
         * 0  -> decoder has not been searched for yet.
         * >0 -> decoder found
         * <0 -> decoder with codec_id == -found_decoder has not been found
         */
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        int found_decoder;
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        int64_t last_duration;

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        /**
         * Those are used for average framerate estimation.
         */
        int64_t fps_first_dts;
        int     fps_first_dts_idx;
        int64_t fps_last_dts;
        int     fps_last_dts_idx;

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    } *info;
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    int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
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    // Timestamp generation support:
    /**
     * Timestamp corresponding to the last dts sync point.
     *
     * Initialized when AVCodecParserContext.dts_sync_point >= 0 and
     * a DTS is received from the underlying container. Otherwise set to
     * AV_NOPTS_VALUE by default.
     */
    int64_t first_dts;
    int64_t cur_dts;
    int64_t last_IP_pts;
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    int last_IP_duration;
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    /**
     * Number of packets to buffer for codec probing
     */
    int probe_packets;

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    /**
     * Number of frames that have been demuxed during av_find_stream_info()
     */
    int codec_info_nb_frames;

    /* av_read_frame() support */
    enum AVStreamParseType need_parsing;
    struct AVCodecParserContext *parser;

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    /**
     * last packet in packet_buffer for this stream when muxing.
     */
    struct AVPacketList *last_in_packet_buffer;
    AVProbeData probe_data;
#define MAX_REORDER_DELAY 16
    int64_t pts_buffer[MAX_REORDER_DELAY+1];

    AVIndexEntry *index_entries; /**< Only used if the format does not
                                    support seeking natively. */
    int nb_index_entries;
    unsigned int index_entries_allocated_size;

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    /**
     * Real base framerate of the stream.
     * This is the lowest framerate with which all timestamps can be
     * represented accurately (it is the least common multiple of all
     * framerates in the stream). Note, this value is just a guess!
     * For example, if the time base is 1/90000 and all frames have either
     * approximately 3600 or 1800 timer ticks, then r_frame_rate will be 50/1.
     *
     * Code outside avformat should access this field using:
     * av_stream_get/set_r_frame_rate(stream)
     */
    AVRational r_frame_rate;

    /**
     * Stream Identifier
     * This is the MPEG-TS stream identifier +1
     * 0 means unknown
     */
    int stream_identifier;

    int64_t interleaver_chunk_size;
    int64_t interleaver_chunk_duration;

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    /**
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     * stream probing state
     * -1   -> probing finished
     *  0   -> no probing requested
     * rest -> perform probing with request_probe being the minimum score to accept.
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     * NOT PART OF PUBLIC API
     */
    int request_probe;
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    /**
     * Indicates that everything up to the next keyframe
     * should be discarded.
     */
    int skip_to_keyframe;
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    /**
     * Number of samples to skip at the start of the frame decoded from the next packet.
     */
    int skip_samples;
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    /**
     * If not 0, the number of samples that should be skipped from the start of
     * the stream (the samples are removed from packets with pts==0, which also
     * assumes negative timestamps do not happen).
     * Intended for use with formats such as mp3 with ad-hoc gapless audio
     * support.
     */
    int64_t start_skip_samples;

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    /**
     * If not 0, the first audio sample that should be discarded from the stream.
     * This is broken by design (needs global sample count), but can't be
     * avoided for broken by design formats such as mp3 with ad-hoc gapless
     * audio support.
     */
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    int64_t first_discard_sample;

    /**
     * The sample after last sample that is intended to be discarded after
     * first_discard_sample. Works on frame boundaries only. Used to prevent
     * early EOF if the gapless info is broken (considered concatenated mp3s).
     */
    int64_t last_discard_sample;
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    /**
     * Number of internally decoded frames, used internally in libavformat, do not access
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     * its lifetime differs from info which is why it is not in that structure.
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     */
    int nb_decoded_frames;
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    /**
     * Timestamp offset added to timestamps before muxing
     * NOT PART OF PUBLIC API
     */
    int64_t mux_ts_offset;

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    /**
     * Internal data to check for wrapping of the time stamp
     */
    int64_t pts_wrap_reference;

    /**
     * Options for behavior, when a wrap is detected.
     *
     * Defined by AV_PTS_WRAP_ values.
     *
     * If correction is enabled, there are two possibilities:
     * If the first time stamp is near the wrap point, the wrap offset
     * will be subtracted, which will create negative time stamps.
     * Otherwise the offset will be added.
     */
    int pts_wrap_behavior;

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    /**
     * Internal data to prevent doing update_initial_durations() twice
     */
    int update_initial_durations_done;
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    /**
     * Internal data to generate dts from pts
     */
    int64_t pts_reorder_error[MAX_REORDER_DELAY+1];
    uint8_t pts_reorder_error_count[MAX_REORDER_DELAY+1];

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    /**
     * Internal data to analyze DTS and detect faulty mpeg streams
     */
    int64_t last_dts_for_order_check;
    uint8_t dts_ordered;
    uint8_t dts_misordered;

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    /**
     * Internal data to inject global side data
     */
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    int inject_global_side_data;
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    /**
     * String containing paris of key and values describing recommended encoder configuration.
     * Paris are separated by ','.
     * Keys are separated from values by '='.
     */
    char *recommended_encoder_configuration;
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    /**
     * display aspect ratio (0 if unknown)
     * - encoding: unused
     * - decoding: Set by libavformat to calculate sample_aspect_ratio internally
     */
    AVRational display_aspect_ratio;
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    struct FFFrac *priv_pts;
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    /**
     * An opaque field for libavformat internal usage.
     * Must not be accessed in any way by callers.
     */
    AVStreamInternal *internal;
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} AVStream;

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AVRational av_stream_get_r_frame_rate(const AVStream *s);
void       av_stream_set_r_frame_rate(AVStream *s, AVRational r);
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struct AVCodecParserContext *av_stream_get_parser(const AVStream *s);
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char* av_stream_get_recommended_encoder_configuration(const AVStream *s);
void  av_stream_set_recommended_encoder_configuration(AVStream *s, char *configuration);
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/**
 * Returns the pts of the last muxed packet + its duration
 *
 * the retuned value is undefined when used with a demuxer.
 */
int64_t    av_stream_get_end_pts(const AVStream *st);

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#define AV_PROGRAM_RUNNING 1

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/**
 * New fields can be added to the end with minor version bumps.
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 * version bump.
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 * sizeof(AVProgram) must not be used outside libav*.
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 */
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typedef struct AVProgram {
    int            id;
    int            flags;
    enum AVDiscard discard;        ///< selects which program to discard and which to feed to the caller
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    unsigned int   *stream_index;
    unsigned int   nb_stream_indexes;
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    AVDictionary *metadata;
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    int program_num;
    int pmt_pid;
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    int pcr_pid;
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    /*****************************************************************
     * All fields below this line are not part of the public API. They
     * may not be used outside of libavformat and can be changed and
     * removed at will.
     * New public fields should be added right above.
     *****************************************************************
     */
    int64_t start_time;
    int64_t end_time;
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    int64_t pts_wrap_reference;    ///< reference dts for wrap detection
    int pts_wrap_behavior;         ///< behavior on wrap detection
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} AVProgram;

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#define AVFMTCTX_NOHEADER      0x0001 /**< signal that no header is present
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                                         (streams are added dynamically) */

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typedef struct AVChapter {
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    int id;                 ///< unique ID to identify the chapter
    AVRational time_base;   ///< time base in which the start/end timestamps are specified
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    int64_t start, end;     ///< chapter start/end time in time_base units
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    AVDictionary *metadata;
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} AVChapter;

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/**
 * Callback used by devices to communicate with application.
 */
typedef int (*av_format_control_message)(struct AVFormatContext *s, int type,
                                         void *data, size_t data_size);

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typedef int (*AVOpenCallback)(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags,
                              const AVIOInterruptCB *int_cb, AVDictionary **options);
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/**
 * The duration of a video can be estimated through various ways, and this enum can be used
 * to know how the duration was estimated.
 */
enum AVDurationEstimationMethod {
    AVFMT_DURATION_FROM_PTS,    ///< Duration accurately estimated from PTSes
    AVFMT_DURATION_FROM_STREAM, ///< Duration estimated from a stream with a known duration
    AVFMT_DURATION_FROM_BITRATE ///< Duration estimated from bitrate (less accurate)
};

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typedef struct AVFormatInternal AVFormatInternal;

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/**
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 * Format I/O context.
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 * New fields can be added to the end with minor version bumps.
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 * version bump.
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 * sizeof(AVFormatContext) must not be used outside libav*, use
 * avformat_alloc_context() to create an AVFormatContext.
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 */
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typedef struct AVFormatContext {
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    /**
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     * A class for logging and @ref avoptions. Set by avformat_alloc_context().
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     * Exports (de)muxer private options if they exist.
     */
    const AVClass *av_class;

    /**
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     * The input container format.
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     *
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     * Demuxing only, set by avformat_open_input().
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     */
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    struct AVInputFormat *iformat;
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    /**
     * The output container format.
     *
     * Muxing only, must be set by the caller before avformat_write_header().
     */
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    struct AVOutputFormat *oformat;
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    /**
     * Format private data. This is an AVOptions-enabled struct
     * if and only if iformat/oformat.priv_class is not NULL.
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     *
     * - muxing: set by avformat_write_header()
     * - demuxing: set by avformat_open_input()
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     */
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    void *priv_data;
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    /**
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     * I/O context.
     *
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     * - demuxing: either set by the user before avformat_open_input() (then
     *             the user must close it manually) or set by avformat_open_input().
     * - muxing: set by the user before avformat_write_header(). The caller must
     *           take care of closing / freeing the IO context.
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     *
     * Do NOT set this field if AVFMT_NOFILE flag is set in
     * iformat/oformat.flags. In such a case, the (de)muxer will handle
     * I/O in some other way and this field will be NULL.
     */
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    AVIOContext *pb;
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    /* stream info */
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    /**
     * Flags signalling stream properties. A combination of AVFMTCTX_*.
     * Set by libavformat.
     */
    int ctx_flags;
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    /**
     * Number of elements in AVFormatContext.streams.
     *
     * Set by avformat_new_stream(), must not be modified by any other code.
     */
    unsigned int nb_streams;
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    /**
     * A list of all streams in the file. New streams are created with
     * avformat_new_stream().
     *
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     * - demuxing: streams are created by libavformat in avformat_open_input().
     *             If AVFMTCTX_NOHEADER is set in ctx_flags, then new streams may also
     *             appear in av_read_frame().
     * - muxing: streams are created by the user before avformat_write_header().
     *
     * Freed by libavformat in avformat_free_context().
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     */
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    AVStream **streams;
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    /**
     * input or output filename
     *
     * - demuxing: set by avformat_open_input()
     * - muxing: may be set by the caller before avformat_write_header()
     */
    char filename[1024];
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    /**
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     * Position of the first frame of the component, in
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     * AV_TIME_BASE fractional seconds. NEVER set this value directly:
     * It is deduced from the AVStream values.
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     *
     * Demuxing only, set by libavformat.
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     */
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    int64_t start_time;
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    /**
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     * Duration of the stream, in AV_TIME_BASE fractional
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     * seconds. Only set this value if you know none of the individual stream
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     * durations and also do not set any of them. This is deduced from the
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     * AVStream values if not set.
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     *
     * Demuxing only, set by libavformat.
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     */
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    int64_t duration;
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    /**
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     * Total stream bitrate in bit/s, 0 if not
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     * available. Never set it directly if the file_size and the
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     * duration are known as FFmpeg can compute it automatically.
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     */
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    int64_t bit_rate;
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    unsigned int packet_size;
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    int max_delay;
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    /**
     * Flags modifying the (de)muxer behaviour. A combination of AVFMT_FLAG_*.
     * Set by the user before avformat_open_input() / avformat_write_header().
     */
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    int flags;
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#define AVFMT_FLAG_GENPTS       0x0001 ///< Generate missing pts even if it requires parsing future frames.
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#define AVFMT_FLAG_IGNIDX       0x0002 ///< Ignore index.
#define AVFMT_FLAG_NONBLOCK     0x0004 ///< Do not block when reading packets from input.
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#define AVFMT_FLAG_IGNDTS       0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
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#define AVFMT_FLAG_NOFILLIN     0x0010 ///< Do not infer any values from other values, just return what is stored in the container
#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
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#define AVFMT_FLAG_NOBUFFER     0x0040 ///< Do not buffer frames when possible
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#define AVFMT_FLAG_CUSTOM_IO    0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
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#define AVFMT_FLAG_DISCARD_CORRUPT  0x0100 ///< Discard frames marked corrupted
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#define AVFMT_FLAG_FLUSH_PACKETS    0x0200 ///< Flush the AVIOContext every packet.
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/**
 * When muxing, try to avoid writing any random/volatile data to the output.
 * This includes any random IDs, real-time timestamps/dates, muxer version, etc.
 *
 * This flag is mainly intended for testing.
 */
#define AVFMT_FLAG_BITEXACT         0x0400
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#define AVFMT_FLAG_MP4A_LATM    0x8000 ///< Enable RTP MP4A-LATM payload
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#define AVFMT_FLAG_SORT_DTS    0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
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#define AVFMT_FLAG_PRIV_OPT    0x20000 ///< Enable use of private options by delaying codec open (this could be made default once all code is converted)
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#define AVFMT_FLAG_KEEP_SIDE_DATA 0x40000 ///< Don't merge side data but keep it separate.
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#define AVFMT_FLAG_FAST_SEEK   0x80000 ///< Enable fast, but inaccurate seeks for some formats
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    /**
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     * Maximum size of the data read from input for determining
     * the input container format.
     * Demuxing only, set by the caller before avformat_open_input().
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     */
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    int64_t probesize;
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    /**
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     * Maximum duration (in AV_TIME_BASE units) of the data read
     * from input in avformat_find_stream_info().
     * Demuxing only, set by the caller before avformat_find_stream_info().
     * Can be set to 0 to let avformat choose using a heuristic.
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     */
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    int64_t max_analyze_duration;
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    const uint8_t *key;
    int keylen;
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    unsigned int nb_programs;
    AVProgram **programs;
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    /**
     * Forced video codec_id.
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     * Demuxing: Set by user.
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     */
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    enum AVCodecID video_codec_id;
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    /**
     * Forced audio codec_id.
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     * Demuxing: Set by user.
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     */
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    enum AVCodecID audio_codec_id;
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    /**
     * Forced subtitle codec_id.
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     * Demuxing: Set by user.
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     */
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    enum AVCodecID subtitle_codec_id;
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    /**
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     * Maximum amount of memory in bytes to use for the index of each stream.
     * If the index exceeds this size, entries will be discarded as
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     * needed to maintain a smaller size. This can lead to slower or less
     * accurate seeking (depends on demuxer).
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     * Demuxers for which a full in-memory index is mandatory will ignore
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     * this.
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     * - muxing: unused
     * - demuxing: set by user
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     */
    unsigned int max_index_size;
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    /**
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     * Maximum amount of memory in bytes to use for buffering frames
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     * obtained from realtime capture devices.
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     */
    unsigned int max_picture_buffer;
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    /**
     * Number of chapters in AVChapter array.
     * When muxing, chapters are normally written in the file header,
     * so nb_chapters should normally be initialized before write_header
     * is called. Some muxers (e.g. mov and mkv) can also write chapters
     * in the trailer.  To write chapters in the trailer, nb_chapters
     * must be zero when write_header is called and non-zero when
     * write_trailer is called.
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     * - muxing: set by user
     * - demuxing: set by libavformat
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     */
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    unsigned int nb_chapters;
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    AVChapter **chapters;
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    /**
     * Metadata that applies to the whole file.
     *
     * - demuxing: set by libavformat in avformat_open_input()
     * - muxing: may be set by the caller before avformat_write_header()
     *
     * Freed by libavformat in avformat_free_context().
     */
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    AVDictionary *metadata;
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    /**
     * Start time of the stream in real world time, in microseconds
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     * since the Unix epoch (00:00 1st January 1970). That is, pts=0 in the
     * stream was captured at this real world time.
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     * - muxing: Set by the caller before avformat_write_header(). If set to
     *           either 0 or AV_NOPTS_VALUE, then the current wall-time will
     *           be used.
     * - demuxing: Set by libavformat. AV_NOPTS_VALUE if unknown. Note that
     *             the value may become known after some number of frames
     *             have been received.
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     */
    int64_t start_time_realtime;
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    /**
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     * The number of frames used for determining the framerate in
     * avformat_find_stream_info().
     * Demuxing only, set by the caller before avformat_find_stream_info().
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     */
    int fps_probe_size;
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    /**
     * Error recognition; higher values will detect more errors but may
     * misdetect some more or less valid parts as errors.
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     * Demuxing only, set by the caller before avformat_open_input().
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     */
    int error_recognition;
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    /**
     * Custom interrupt callbacks for the I/O layer.
     *
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     * demuxing: set by the user before avformat_open_input().
     * muxing: set by the user before avformat_write_header()
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     * (mainly useful for AVFMT_NOFILE formats). The callback
     * should also be passed to avio_open2() if it's used to
     * open the file.
     */
    AVIOInterruptCB interrupt_callback;

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    /**
     * Flags to enable debugging.
     */
    int debug;
#define FF_FDEBUG_TS        0x0001
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    /**
     * Maximum buffering duration for interleaving.
     *
     * To ensure all the streams are interleaved correctly,
     * av_interleaved_write_frame() will wait until it has at least one packet
     * for each stream before actually writing any packets to the output file.
     * When some streams are "sparse" (i.e. there are large gaps between
     * successive packets), this can result in excessive buffering.
     *
     * This field specifies the maximum difference between the timestamps of the
     * first and the last packet in the muxing queue, above which libavformat
     * will output a packet regardless of whether it has queued a packet for all
     * the streams.
     *
     * Muxing only, set by the caller before avformat_write_header().
     */
    int64_t max_interleave_delta;

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    /**
     * Allow non-standard and experimental extension
     * @see AVCodecContext.strict_std_compliance
     */
    int strict_std_compliance;
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    /**
     * Flags for the user to detect events happening on the file. Flags must
     * be cleared by the user once the event has been handled.
     * A combination of AVFMT_EVENT_FLAG_*.
     */
    int event_flags;
#define AVFMT_EVENT_FLAG_METADATA_UPDATED 0x0001 ///< The call resulted in updated metadata.

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    /**
     * Maximum number of packets to read while waiting for the first timestamp.
     * Decoding only.
     */
    int max_ts_probe;

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    /**
     * Avoid negative timestamps during muxing.
     * Any value of the AVFMT_AVOID_NEG_TS_* constants.
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     * Note, this only works when using av_interleaved_write_frame. (interleave_packet_per_dts is in use)
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     * - muxing: Set by user
     * - demuxing: unused
     */
    int avoid_negative_ts;
#define AVFMT_AVOID_NEG_TS_AUTO             -1 ///< Enabled when required by target format
#define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
#define AVFMT_AVOID_NEG_TS_MAKE_ZERO         2 ///< Shift timestamps so that they start at 0

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    /**
     * Transport stream id.
     * This will be moved into demuxer private options. Thus no API/ABI compatibility
     */
    int ts_id;
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    /**
     * Audio preload in microseconds.
     * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
     * - encoding: Set by user via AVOptions (NO direct access)
     * - decoding: unused
     */
    int audio_preload;
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    /**
     * Max chunk time in microseconds.
     * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
     * - encoding: Set by user via AVOptions (NO direct access)
     * - decoding: unused
     */
    int max_chunk_duration;

    /**
     * Max chunk size in bytes
     * Note, not all formats support this and unpredictable things may happen if it is used when not supported.
     * - encoding: Set by user via AVOptions (NO direct access)
     * - decoding: unused
     */
    int max_chunk_size;

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    /**
     * forces the use of wallclock timestamps as pts/dts of packets
     * This has undefined results in the presence of B frames.
     * - encoding: unused
     * - decoding: Set by user via AVOptions (NO direct access)
     */
    int use_wallclock_as_timestamps;

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    /**
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     * avio flags, used to force AVIO_FLAG_DIRECT.
     * - encoding: unused
     * - decoding: Set by user via AVOptions (NO direct access)
     */
    int avio_flags;

    /**
     * The duration field can be estimated through various ways, and this field can be used
     * to know how the duration was estimated.
     * - encoding: unused
     * - decoding: Read by user via AVOptions (NO direct access)
     */
    enum AVDurationEstimationMethod duration_estimation_method;

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    /**
     * Skip initial bytes when opening stream
     * - encoding: unused
     * - decoding: Set by user via AVOptions (NO direct access)
     */
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    int64_t skip_initial_bytes;
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    /**
     * Correct single timestamp overflows
     * - encoding: unused
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     * - decoding: Set by user via AVOptions (NO direct access)
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     */
    unsigned int correct_ts_overflow;

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    /**
     * Force seeking to any (also non key) frames.
     * - encoding: unused
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     * - decoding: Set by user via AVOptions (NO direct access)
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     */
    int seek2any;

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    /**
     * Flush the I/O context after each packet.
     * - encoding: Set by user via AVOptions (NO direct access)
     * - decoding: unused
     */
    int flush_packets;

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    /**
     * format probing score.
     * The maximal score is AVPROBE_SCORE_MAX, its set when the demuxer probes
     * the format.
     * - encoding: unused
     * - decoding: set by avformat, read by user via av_format_get_probe_score() (NO direct access)
     */
    int probe_score;

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    /**
     * number of bytes to read maximally to identify format.
     * - encoding: unused
     * - decoding: set by user through AVOPtions (NO direct access)
     */
    int format_probesize;

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    /**
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     * ',' separated list of allowed decoders.
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     * If NULL then all are allowed
     * - encoding: unused
     * - decoding: set by user through AVOptions (NO direct access)
     */
    char *codec_whitelist;

    /**
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     * ',' separated list of allowed demuxers.
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     * If NULL then all are allowed
     * - encoding: unused
     * - decoding: set by user through AVOptions (NO direct access)
     */
    char *format_whitelist;

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    /**
     * An opaque field for libavformat internal usage.
     * Must not be accessed in any way by callers.
     */
    AVFormatInternal *internal;
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    /**
     * IO repositioned flag.
     * This is set by avformat when the underlaying IO context read pointer
     * is repositioned, for example when doing byte based seeking.
     * Demuxers can use the flag to detect such changes.
     */
    int io_repositioned;
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    /**
     * Forced video codec.
     * This allows forcing a specific decoder, even when there are multiple with
     * the same codec_id.
     * Demuxing: Set by user via av_format_set_video_codec (NO direct access).
     */
    AVCodec *video_codec;

    /**
     * Forced audio codec.
     * This allows forcing a specific decoder, even when there are multiple with
     * the same codec_id.
     * Demuxing: Set by user via av_format_set_audio_codec (NO direct access).
     */
    AVCodec *audio_codec;

    /**
     * Forced subtitle codec.
     * This allows forcing a specific decoder, even when there are multiple with
     * the same codec_id.
     * Demuxing: Set by user via av_format_set_subtitle_codec (NO direct access).
     */
    AVCodec *subtitle_codec;
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    /**
     * Forced data codec.
     * This allows forcing a specific decoder, even when there are multiple with
     * the same codec_id.
     * Demuxing: Set by user via av_format_set_data_codec (NO direct access).
     */
    AVCodec *data_codec;

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    /**
     * Number of bytes to be written as padding in a metadata header.
     * Demuxing: Unused.
     * Muxing: Set by user via av_format_set_metadata_header_padding.
     */
    int metadata_header_padding;
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    /**
     * User data.
     * This is a place for some private data of the user.
     * Mostly usable with control_message_cb or any future callbacks in device's context.
     */
    void *opaque;

    /**
     * Callback used by devices to communicate with application.
     */
    av_format_control_message control_message_cb;

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    /**
     * Output timestamp offset, in microseconds.
     * Muxing: set by user via AVOptions (NO direct access)
     */
    int64_t output_ts_offset;
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    /**
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     * dump format separator.
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     * can be ", " or "\n      " or anything else
     * Code outside libavformat should access this field using AVOptions
     * (NO direct access).
     * - muxing: Set by user.
     * - demuxing: Set by user.
     */
    uint8_t *dump_separator;
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    /**
     * Forced Data codec_id.
     * Demuxing: Set by user.
     */
    enum AVCodecID data_codec_id;
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    /**
     * Called to open further IO contexts when needed for demuxing.
     *
     * This can be set by the user application to perform security checks on
     * the URLs before opening them.
     * The function should behave like avio_open2(), AVFormatContext is provided
     * as contextual information and to reach AVFormatContext.opaque.
     *
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     * If NULL then some simple checks are used together with avio_open2().
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     *
     * Must not be accessed directly from outside avformat.
     * @See av_format_set_open_cb()
     *
     * Demuxing: Set by user.
     */
    int (*open_cb)(struct AVFormatContext *s, AVIOContext **p, const char *url, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options);
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} AVFormatContext;

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int av_format_get_probe_score(const AVFormatContext *s);
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AVCodec * av_format_get_video_codec(const AVFormatContext *s);
void      av_format_set_video_codec(AVFormatContext *s, AVCodec *c);
AVCodec * av_format_get_audio_codec(const AVFormatContext *s);
void      av_format_set_audio_codec(AVFormatContext *s, AVCodec *c);
AVCodec * av_format_get_subtitle_codec(const AVFormatContext *s);
void      av_format_set_subtitle_codec(AVFormatContext *s, AVCodec *c);
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AVCodec * av_format_get_data_codec(const AVFormatContext *s);
void      av_format_set_data_codec(AVFormatContext *s, AVCodec *c);
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int       av_format_get_metadata_header_padding(const AVFormatContext *s);
void      av_format_set_metadata_header_padding(AVFormatContext *s, int c);
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void *    av_format_get_opaque(const AVFormatContext *s);
void      av_format_set_opaque(AVFormatContext *s, void *opaque);
av_format_control_message av_format_get_control_message_cb(const AVFormatContext *s);
void      av_format_set_control_message_cb(AVFormatContext *s, av_format_control_message callback);
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AVOpenCallback av_format_get_open_cb(const AVFormatContext *s);
void      av_format_set_open_cb(AVFormatContext *s, AVOpenCallback callback);
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/**
 * This function will cause global side data to be injected in the next packet
 * of each stream as well as after any subsequent seek.
 */
void av_format_inject_global_side_data(AVFormatContext *s);

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/**
 * Returns the method used to set ctx->duration.
 *
 * @return AVFMT_DURATION_FROM_PTS, AVFMT_DURATION_FROM_STREAM, or AVFMT_DURATION_FROM_BITRATE.
 */
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enum AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext* ctx);
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typedef struct AVPacketList {
    AVPacket pkt;
    struct AVPacketList *next;
} AVPacketList;

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/**
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 * @defgroup lavf_core Core functions
 * @ingroup libavf
 *
 * Functions for querying libavformat capabilities, allocating core structures,
 * etc.
 * @{
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 */

/**
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 * Return the LIBAVFORMAT_VERSION_INT constant.
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 */
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unsigned avformat_version(void);
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/**
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 * Return the libavformat build-time configuration.
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 */
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const char *avformat_configuration(void);
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/**
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 * Return the libavformat license.
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 */
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const char *avformat_license(void);
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/**
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 * Initialize libavformat and register all the muxers, demuxers and
 * protocols. If you do not call this function, then you can select
 * exactly which formats you want to support.
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 *
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 * @see av_register_input_format()
 * @see av_register_output_format()
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 */
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void av_register_all(void);

void av_register_input_format(AVInputFormat *format);
void av_register_output_format(AVOutputFormat *format);
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/**
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 * Do global initialization of network components. This is optional,
 * but recommended, since it avoids the overhead of implicitly
 * doing the setup for each session.
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 *
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 * Calling this function will become mandatory if using network
 * protocols at some major version bump.
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 */
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int avformat_network_init(void);
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/**
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 * Undo the initialization done by avformat_network_init.
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 */
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int avformat_network_deinit(void);
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/**
 * If f is NULL, returns the first registered input format,
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 * if f is non-NULL, returns the next registered input format after f
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 * or NULL if f is the last one.
 */
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AVInputFormat  *av_iformat_next(const AVInputFormat  *f);
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/**
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 * If f is NULL, returns the first registered output format,
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 * if f is non-NULL, returns the next registered output format after f
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 * or NULL if f is the last one.
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 */
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AVOutputFormat *av_oformat_next(const AVOutputFormat *f);
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/**
 * Allocate an AVFormatContext.
 * avformat_free_context() can be used to free the context and everything
 * allocated by the framework within it.
 */
AVFormatContext *avformat_alloc_context(void);
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/**
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 * Free an AVFormatContext and all its streams.
 * @param s context to free
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 */
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void avformat_free_context(AVFormatContext *s);
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/**
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 * Get the AVClass for AVFormatContext. It can be used in combination with
 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
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 *
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 * @see av_opt_find().
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 */
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const AVClass *avformat_get_class(void);
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/**
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 * Add a new stream to a media file.
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 *
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 * When demuxing, it is called by the demuxer in read_header(). If the
 * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
 * be called in read_packet().
 *
 * When muxing, should be called by the user before avformat_write_header().
 *
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 * User is required to call avcodec_close() and avformat_free_context() to
 * clean up the allocation by avformat_new_stream().
 *
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 * @param s media file handle
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 * @param c If non-NULL, the AVCodecContext corresponding to the new stream
 * will be initialized to use this codec. This is needed for e.g. codec-specific
 * defaults to be set, so codec should be provided if it is known.
 *
 * @return newly created stream or NULL on error.
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 */
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AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c);
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/**
 * Allocate new information from stream.
 *
 * @param stream stream
 * @param type desired side information type
 * @param size side information size
 * @return pointer to fresh allocated data or NULL otherwise
 */
uint8_t *av_stream_new_side_data(AVStream *stream,
                                 enum AVPacketSideDataType type, int size);
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/**
 * Get side information from stream.
 *
 * @param stream stream
 * @param type desired side information type
 * @param size pointer for side information size to store (optional)
 * @return pointer to data if present or NULL otherwise
 */
uint8_t *av_stream_get_side_data(AVStream *stream,
                                 enum AVPacketSideDataType type, int *size);

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AVProgram *av_new_program(AVFormatContext *s, int id);
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/**
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 * @}
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 */
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/**
 * Allocate an AVFormatContext for an output format.
 * avformat_free_context() can be used to free the context and
 * everything allocated by the framework within it.
 *
 * @param *ctx is set to the created format context, or to NULL in
 * case of failure
 * @param oformat format to use for allocating the context, if NULL
 * format_name and filename are used instead
 * @param format_name the name of output format to use for allocating the
 * context, if NULL filename is used instead
 * @param filename the name of the filename to use for allocating the
 * context, may be NULL
 * @return >= 0 in case of success, a negative AVERROR code in case of
 * failure
 */
int avformat_alloc_output_context2(AVFormatContext **ctx, AVOutputFormat *oformat,
                                   const char *format_name, const char *filename);

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/**
 * @addtogroup lavf_decoding
 * @{
 */
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/**
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 * Find AVInputFormat based on the short name of the input format.
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 */
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AVInputFormat *av_find_input_format(const char *short_name);
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/**
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 * Guess the file format.
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 *
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 * @param pd        data to be probed
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 * @param is_opened Whether the file is already opened; determines whether
 *                  demuxers with or without AVFMT_NOFILE are probed.
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 */
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AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened);
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/**
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 * Guess the file format.
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 *
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 * @param pd        data to be probed
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 * @param is_opened Whether the file is already opened; determines whether
 *                  demuxers with or without AVFMT_NOFILE are probed.
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 * @param score_max A probe score larger that this is required to accept a
 *                  detection, the variable is set to the actual detection
 *                  score afterwards.
 *                  If the score is <= AVPROBE_SCORE_MAX / 4 it is recommended
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 *                  to retry with a larger probe buffer.
 */
AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max);

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/**
 * Guess the file format.
 *
 * @param is_opened Whether the file is already opened; determines whether
 *                  demuxers with or without AVFMT_NOFILE are probed.
 * @param score_ret The score of the best detection.
 */
AVInputFormat *av_probe_input_format3(AVProbeData *pd, int is_opened, int *score_ret);

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/**
 * Probe a bytestream to determine the input format. Each time a probe returns
 * with a score that is too low, the probe buffer size is increased and another
 * attempt is made. When the maximum probe size is reached, the input format
 * with the highest score is returned.
 *
 * @param pb the bytestream to probe
 * @param fmt the input format is put here
 * @param filename the filename of the stream
 * @param logctx the log context
 * @param offset the offset within the bytestream to probe from
 * @param max_probe_size the maximum probe buffer size (zero for default)
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 * @return the score in case of success, a negative value corresponding to an
 *         the maximal score is AVPROBE_SCORE_MAX
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 * AVERROR code otherwise
 */
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int av_probe_input_buffer2(AVIOContext *pb, AVInputFormat **fmt,
                           const char *filename, void *logctx,
                           unsigned int offset, unsigned int max_probe_size);

/**
 * Like av_probe_input_buffer2() but returns 0 on success
 */
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int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
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                          const char *filename, void *logctx,
                          unsigned int offset, unsigned int max_probe_size);

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/**
 * Open an input stream and read the header. The codecs are not opened.
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 * The stream must be closed with avformat_close_input().
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 *
 * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
 *           May be a pointer to NULL, in which case an AVFormatContext is allocated by this
 *           function and written into ps.
 *           Note that a user-supplied AVFormatContext will be freed on failure.
 * @param filename Name of the stream to open.
 * @param fmt If non-NULL, this parameter forces a specific input format.
 *            Otherwise the format is autodetected.
 * @param options  A dictionary filled with AVFormatContext and demuxer-private options.
 *                 On return this parameter will be destroyed and replaced with a dict containing
 *                 options that were not found. May be NULL.
 *
 * @return 0 on success, a negative AVERROR on failure.
 *
 * @note If you want to use custom IO, preallocate the format context and set its pb field.
 */
int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options);
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attribute_deprecated
int av_demuxer_open(AVFormatContext *ic);
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/**
 * Read packets of a media file to get stream information. This
 * is useful for file formats with no headers such as MPEG. This
 * function also computes the real framerate in case of MPEG-2 repeat
 * frame mode.
 * The logical file position is not changed by this function;
 * examined packets may be buffered for later processing.
 *
 * @param ic media file handle
 * @param options  If non-NULL, an ic.nb_streams long array of pointers to
 *                 dictionaries, where i-th member contains options for
 *                 codec corresponding to i-th stream.
 *                 On return each dictionary will be filled with options that were not found.
 * @return >=0 if OK, AVERROR_xxx on error
 *
 * @note this function isn't guaranteed to open all the codecs, so
 *       options being non-empty at return is a perfectly normal behavior.
 *
 * @todo Let the user decide somehow what information is needed so that
 *       we do not waste time getting stuff the user does not need.
 */
int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options);
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/**
 * Find the programs which belong to a given stream.
 *
 * @param ic    media file handle
 * @param last  the last found program, the search will start after this
 *              program, or from the beginning if it is NULL
 * @param s     stream index
 * @return the next program which belongs to s, NULL if no program is found or
 *         the last program is not among the programs of ic.
 */
AVProgram *av_find_program_from_stream(AVFormatContext *ic, AVProgram *last, int s);

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/**
 * Find the "best" stream in the file.
 * The best stream is determined according to various heuristics as the most
 * likely to be what the user expects.
 * If the decoder parameter is non-NULL, av_find_best_stream will find the
 * default decoder for the stream's codec; streams for which no decoder can
 * be found are ignored.
 *
 * @param ic                media file handle
 * @param type              stream type: video, audio, subtitles, etc.
 * @param wanted_stream_nb  user-requested stream number,
 *                          or -1 for automatic selection
 * @param related_stream    try to find a stream related (eg. in the same
 *                          program) to this one, or -1 if none
 * @param decoder_ret       if non-NULL, returns the decoder for the
 *                          selected stream
 * @param flags             flags; none are currently defined
 * @return  the non-negative stream number in case of success,
 *          AVERROR_STREAM_NOT_FOUND if no stream with the requested type
 *          could be found,
 *          AVERROR_DECODER_NOT_FOUND if streams were found but no decoder
 * @note  If av_find_best_stream returns successfully and decoder_ret is not
 *        NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.
 */
int av_find_best_stream(AVFormatContext *ic,
                        enum AVMediaType type,
                        int wanted_stream_nb,
                        int related_stream,
                        AVCodec **decoder_ret,
                        int flags);

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/**
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 * Return the next frame of a stream.
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 * This function returns what is stored in the file, and does not validate
 * that what is there are valid frames for the decoder. It will split what is
 * stored in the file into frames and return one for each call. It will not
 * omit invalid data between valid frames so as to give the decoder the maximum
 * information possible for decoding.
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 *
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 * If pkt->buf is NULL, then the packet is valid until the next
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 * av_read_frame() or until avformat_close_input(). Otherwise the packet
 * is valid indefinitely. In both cases the packet must be freed with
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 * av_packet_unref when it is no longer needed. For video, the packet contains
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 * exactly one frame. For audio, it contains an integer number of frames if each
 * frame has a known fixed size (e.g. PCM or ADPCM data). If the audio frames
 * have a variable size (e.g. MPEG audio), then it contains one frame.
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 *
 * pkt->pts, pkt->dts and pkt->duration are always set to correct
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 * values in AVStream.time_base units (and guessed if the format cannot
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 * provide them). pkt->pts can be AV_NOPTS_VALUE if the video format
 * has B-frames, so it is better to rely on pkt->dts if you do not
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 * decompress the payload.
 *
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 * @return 0 if OK, < 0 on error or end of file
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 */
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int av_read_frame(AVFormatContext *s, AVPacket *pkt);
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/**
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 * Seek to the keyframe at timestamp.
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 * 'timestamp' in 'stream_index'.
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 *
 * @param s media file handle
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 * @param stream_index If stream_index is (-1), a default
 * stream is selected, and timestamp is automatically converted
 * from AV_TIME_BASE units to the stream specific time_base.
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 * @param timestamp Timestamp in AVStream.time_base units
 *        or, if no stream is specified, in AV_TIME_BASE units.
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 * @param flags flags which select direction and seeking mode
 * @return >= 0 on success
 */
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int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
                  int flags);
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/**
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 * Seek to timestamp ts.
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 * Seeking will be done so that the point from which all active streams
 * can be presented successfully will be closest to ts and within min/max_ts.
 * Active streams are all streams that have AVStream.discard < AVDISCARD_ALL.
 *
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 * If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
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 * are the file position (this may not be supported by all demuxers).
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 * If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
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 * in the stream with stream_index (this may not be supported by all demuxers).
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 * Otherwise all timestamps are in units of the stream selected by stream_index
 * or if stream_index is -1, in AV_TIME_BASE units.
 * If flags contain AVSEEK_FLAG_ANY, then non-keyframes are treated as
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 * keyframes (this may not be supported by all demuxers).
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 * If flags contain AVSEEK_FLAG_BACKWARD, it is ignored.
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 *
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 * @param s media file handle
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 * @param stream_index index of the stream which is used as time base reference
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 * @param min_ts smallest acceptable timestamp
 * @param ts target timestamp
 * @param max_ts largest acceptable timestamp
 * @param flags flags
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 * @return >=0 on success, error code otherwise
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 *
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 * @note This is part of the new seek API which is still under construction.
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 *       Thus do not use this yet. It may change at any time, do not expect
 *       ABI compatibility yet!
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 */
int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);

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/**
 * Discard all internally buffered data. This can be useful when dealing with
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 * discontinuities in the byte stream. Generally works only with formats that
 * can resync. This includes headerless formats like MPEG-TS/TS but should also
 * work with NUT, Ogg and in a limited way AVI for example.
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 *
 * The set of streams, the detected duration, stream parameters and codecs do
 * not change when calling this function. If you want a complete reset, it's
 * better to open a new AVFormatContext.
 *
 * This does not flush the AVIOContext (s->pb). If necessary, call
 * avio_flush(s->pb) before calling this function.
 *
 * @param s media file handle
 * @return >=0 on success, error code otherwise
 */
int avformat_flush(AVFormatContext *s);

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/**
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 * Start playing a network-based stream (e.g. RTSP stream) at the
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 * current position.
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 */
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int av_read_play(AVFormatContext *s);
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/**
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 * Pause a network-based stream (e.g. RTSP stream).
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 *
 * Use av_read_play() to resume it.
 */
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int av_read_pause(AVFormatContext *s);
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/**
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 * Close an opened input AVFormatContext. Free it and all its contents
 * and set *s to NULL.
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 */
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void avformat_close_input(AVFormatContext **s);
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/**
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 * @}
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 */

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#define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
#define AVSEEK_FLAG_BYTE     2 ///< seeking based on position in bytes
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#define AVSEEK_FLAG_ANY      4 ///< seek to any frame, even non-keyframes
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#define AVSEEK_FLAG_FRAME    8 ///< seeking based on frame number
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/**
 * @addtogroup lavf_encoding
 * @{
 */
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/**
 * Allocate the stream private data and write the stream header to
 * an output media file.
 *
 * @param s Media file handle, must be allocated with avformat_alloc_context().
 *          Its oformat field must be set to the desired output format;
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 *          Its pb field must be set to an already opened AVIOContext.
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 * @param options  An AVDictionary filled with AVFormatContext and muxer-private options.
 *                 On return this parameter will be destroyed and replaced with a dict containing
 *                 options that were not found. May be NULL.
 *
 * @return 0 on success, negative AVERROR on failure.
 *
 * @see av_opt_find, av_dict_set, avio_open, av_oformat_next.
 */
int avformat_write_header(AVFormatContext *s, AVDictionary **options);

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/**
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 * Write a packet to an output media file.
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 *
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 * This function passes the packet directly to the muxer, without any buffering
 * or reordering. The caller is responsible for correctly interleaving the
 * packets if the format requires it. Callers that want libavformat to handle
 * the interleaving should call av_interleaved_write_frame() instead of this
 * function.
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 *
 * @param s media file handle
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 * @param pkt The packet containing the data to be written. Note that unlike
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 *            av_interleaved_write_frame(), this function does not take
 *            ownership of the packet passed to it (though some muxers may make
 *            an internal reference to the input packet).
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 *            <br>
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 *            This parameter can be NULL (at any time, not just at the end), in
 *            order to immediately flush data buffered within the muxer, for
 *            muxers that buffer up data internally before writing it to the
 *            output.
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 *            <br>
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 *            Packet's @ref AVPacket.stream_index "stream_index" field must be
 *            set to the index of the corresponding stream in @ref
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 *            AVFormatContext.streams "s->streams".
 *            <br>
 *            The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
 *            must be set to correct values in the stream's timebase (unless the
 *            output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
 *            they can be set to AV_NOPTS_VALUE).
 *            The dts for subsequent packets passed to this function must be strictly
 *            increasing when compared in their respective timebases (unless the
 *            output format is flagged with the AVFMT_TS_NONSTRICT, then they
 *            merely have to be nondecreasing).  @ref AVPacket.duration
 *            "duration") should also be set if known.
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 * @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
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 *
 * @see av_interleaved_write_frame()
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 */
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int av_write_frame(AVFormatContext *s, AVPacket *pkt);
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/**
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 * Write a packet to an output media file ensuring correct interleaving.
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 *
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 * This function will buffer the packets internally as needed to make sure the
 * packets in the output file are properly interleaved in the order of
 * increasing dts. Callers doing their own interleaving should call
 * av_write_frame() instead of this function.
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 *
 * @param s media file handle
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 * @param pkt The packet containing the data to be written.
 *            <br>
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 *            If the packet is reference-counted, this function will take
 *            ownership of this reference and unreference it later when it sees
 *            fit.
 *            The caller must not access the data through this reference after
 *            this function returns. If the packet is not reference-counted,
 *            libavformat will make a copy.
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 *            <br>
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 *            This parameter can be NULL (at any time, not just at the end), to
 *            flush the interleaving queues.
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 *            <br>
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 *            Packet's @ref AVPacket.stream_index "stream_index" field must be
 *            set to the index of the corresponding stream in @ref
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 *            AVFormatContext.streams "s->streams".
 *            <br>
 *            The timestamps (@ref AVPacket.pts "pts", @ref AVPacket.dts "dts")
 *            must be set to correct values in the stream's timebase (unless the
 *            output format is flagged with the AVFMT_NOTIMESTAMPS flag, then
 *            they can be set to AV_NOPTS_VALUE).
 *            The dts for subsequent packets in one stream must be strictly
 *            increasing (unless the output format is flagged with the
 *            AVFMT_TS_NONSTRICT, then they merely have to be nondecreasing).
 *            @ref AVPacket.duration "duration") should also be set if known.
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 *
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 * @return 0 on success, a negative AVERROR on error. Libavformat will always
 *         take care of freeing the packet, even if this function fails.
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 *
 * @see av_write_frame(), AVFormatContext.max_interleave_delta
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 */
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int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
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/**
 * Write a uncoded frame to an output media file.
 *
 * The frame must be correctly interleaved according to the container
 * specification; if not, then av_interleaved_write_frame() must be used.
 *
 * See av_interleaved_write_frame() for details.
 */
int av_write_uncoded_frame(AVFormatContext *s, int stream_index,
                           AVFrame *frame);

/**
 * Write a uncoded frame to an output media file.
 *
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 * If the muxer supports it, this function makes it possible to write an AVFrame
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 * structure directly, without encoding it into a packet.
 * It is mostly useful for devices and similar special muxers that use raw
 * video or PCM data and will not serialize it into a byte stream.
 *
 * To test whether it is possible to use it with a given muxer and stream,
 * use av_write_uncoded_frame_query().
 *
 * The caller gives up ownership of the frame and must not access it
 * afterwards.
 *
 * @return  >=0 for success, a negative code on error
 */
int av_interleaved_write_uncoded_frame(AVFormatContext *s, int stream_index,
                                       AVFrame *frame);

/**
 * Test whether a muxer supports uncoded frame.
 *
 * @return  >=0 if an uncoded frame can be written to that muxer and stream,
 *          <0 if not
 */
int av_write_uncoded_frame_query(AVFormatContext *s, int stream_index);

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/**
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 * Write the stream trailer to an output media file and free the
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 * file private data.
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 *
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 * May only be called after a successful call to avformat_write_header.
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 *
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 * @param s media file handle
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 * @return 0 if OK, AVERROR_xxx on error
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 */
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int av_write_trailer(AVFormatContext *s);
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/**
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 * Return the output format in the list of registered output formats
 * which best matches the provided parameters, or return NULL if
 * there is no match.
 *
 * @param short_name if non-NULL checks if short_name matches with the
 * names of the registered formats
 * @param filename if non-NULL checks if filename terminates with the
 * extensions of the registered formats
 * @param mime_type if non-NULL checks if mime_type matches with the
 * MIME type of the registered formats
 */
AVOutputFormat *av_guess_format(const char *short_name,
                                const char *filename,
                                const char *mime_type);

/**
 * Guess the codec ID based upon muxer and filename.
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 */
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enum AVCodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
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                            const char *filename, const char *mime_type,
                            enum AVMediaType type);
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/**
 * Get timing information for the data currently output.
 * The exact meaning of "currently output" depends on the format.
 * It is mostly relevant for devices that have an internal buffer and/or
 * work in real time.
 * @param s          media file handle
 * @param stream     stream in the media file
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 * @param[out] dts   DTS of the last packet output for the stream, in stream
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 *                   time_base units
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 * @param[out] wall  absolute time when that packet whas output,
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 *                   in microsecond
 * @return  0 if OK, AVERROR(ENOSYS) if the format does not support it
 * Note: some formats or devices may not allow to measure dts and wall
 * atomically.
 */
int av_get_output_timestamp(struct AVFormatContext *s, int stream,
                            int64_t *dts, int64_t *wall);

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/**
 * @}
 */
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/**
 * @defgroup lavf_misc Utility functions
 * @ingroup libavf
 * @{
 *
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 * Miscellaneous utility functions related to both muxing and demuxing
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 * (or neither).
 */

/**
 * Send a nice hexadecimal dump of a buffer to the specified file stream.
 *
 * @param f The file stream pointer where the dump should be sent to.
 * @param buf buffer
 * @param size buffer size
 *
 * @see av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2
 */
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void av_hex_dump(FILE *f, const uint8_t *buf, int size);
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/**
 * Send a nice hexadecimal dump of a buffer to the log.
 *
 * @param avcl A pointer to an arbitrary struct of which the first field is a
 * pointer to an AVClass struct.
 * @param level The importance level of the message, lower values signifying
 * higher importance.
 * @param buf buffer
 * @param size buffer size
 *
 * @see av_hex_dump, av_pkt_dump2, av_pkt_dump_log2
 */
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void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
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/**
 * Send a nice dump of a packet to the specified file stream.
 *
 * @param f The file stream pointer where the dump should be sent to.
 * @param pkt packet to dump
 * @param dump_payload True if the payload must be displayed, too.
 * @param st AVStream that the packet belongs to
 */
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void av_pkt_dump2(FILE *f, const AVPacket *pkt, int dump_payload, const AVStream *st);
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/**
 * Send a nice dump of a packet to the log.
 *
 * @param avcl A pointer to an arbitrary struct of which the first field is a
 * pointer to an AVClass struct.
 * @param level The importance level of the message, lower values signifying
 * higher importance.
 * @param pkt packet to dump
 * @param dump_payload True if the payload must be displayed, too.
 * @param st AVStream that the packet belongs to
 */
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void av_pkt_dump_log2(void *avcl, int level, const AVPacket *pkt, int dump_payload,
                      const AVStream *st);
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/**
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 * Get the AVCodecID for the given codec tag tag.
 * If no codec id is found returns AV_CODEC_ID_NONE.
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 *
 * @param tags list of supported codec_id-codec_tag pairs, as stored
 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
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 * @param tag  codec tag to match to a codec ID
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 */
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enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
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/**
 * Get the codec tag for the given codec id id.
 * If no codec tag is found returns 0.
 *
 * @param tags list of supported codec_id-codec_tag pairs, as stored
 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
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 * @param id   codec ID to match to a codec tag
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 */
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unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id);
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/**
 * Get the codec tag for the given codec id.
 *
 * @param tags list of supported codec_id - codec_tag pairs, as stored
 * in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
 * @param id codec id that should be searched for in the list
 * @param tag A pointer to the found tag
 * @return 0 if id was not found in tags, > 0 if it was found
 */
int av_codec_get_tag2(const struct AVCodecTag * const *tags, enum AVCodecID id,
                      unsigned int *tag);

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int av_find_default_stream_index(AVFormatContext *s);

/**
 * Get the index for a specific timestamp.
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 *
 * @param st        stream that the timestamp belongs to
 * @param timestamp timestamp to retrieve the index for
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 * @param flags if AVSEEK_FLAG_BACKWARD then the returned index will correspond
 *                 to the timestamp which is <= the requested one, if backward
 *                 is 0, then it will be >=
 *              if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise
 * @return < 0 if no such timestamp could be found
 */
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);

/**
 * Add an index entry into a sorted list. Update the entry if the list
 * already contains it.
 *
 * @param timestamp timestamp in the time base of the given stream
 */
int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp,
                       int size, int distance, int flags);


/**
 * Split a URL string into components.
 *
 * The pointers to buffers for storing individual components may be null,
 * in order to ignore that component. Buffers for components not found are
 * set to empty strings. If the port is not found, it is set to a negative
 * value.
 *
 * @param proto the buffer for the protocol
 * @param proto_size the size of the proto buffer
 * @param authorization the buffer for the authorization
 * @param authorization_size the size of the authorization buffer
 * @param hostname the buffer for the host name
 * @param hostname_size the size of the hostname buffer
 * @param port_ptr a pointer to store the port number in
 * @param path the buffer for the path
 * @param path_size the size of the path buffer
 * @param url the URL to split
 */
void av_url_split(char *proto,         int proto_size,
                  char *authorization, int authorization_size,
                  char *hostname,      int hostname_size,
                  int *port_ptr,
                  char *path,          int path_size,
                  const char *url);

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/**
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 * Print detailed information about the input or output format, such as
 * duration, bitrate, streams, container, programs, metadata, side data,
 * codec and time base.
 *
 * @param ic        the context to analyze
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 * @param index     index of the stream to dump information about
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 * @param url       the URL to print, such as source or destination file
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 * @param is_output Select whether the specified context is an input(0) or output(1)
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 */
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void av_dump_format(AVFormatContext *ic,
                    int index,
                    const char *url,
                    int is_output);
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/**
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 * Return in 'buf' the path with '%d' replaced by a number.
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 *
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 * Also handles the '%0nd' format where 'n' is the total number
 * of digits and '%%'.
 *
 * @param buf destination buffer
 * @param buf_size destination buffer size
 * @param path numbered sequence string
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 * @param number frame number
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 * @return 0 if OK, -1 on format error
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 */
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int av_get_frame_filename(char *buf, int buf_size,
                          const char *path, int number);
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/**
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 * Check whether filename actually is a numbered sequence generator.
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 *
 * @param filename possible numbered sequence string
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 * @return 1 if a valid numbered sequence string, 0 otherwise
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 */
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int av_filename_number_test(const char *filename);
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/**
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 * Generate an SDP for an RTP session.
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 *
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 * Note, this overwrites the id values of AVStreams in the muxer contexts
 * for getting unique dynamic payload types.
 *
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 * @param ac array of AVFormatContexts describing the RTP streams. If the
 *           array is composed by only one context, such context can contain
 *           multiple AVStreams (one AVStream per RTP stream). Otherwise,
 *           all the contexts in the array (an AVCodecContext per RTP stream)
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 *           must contain only one AVStream.
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 * @param n_files number of AVCodecContexts contained in ac
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 * @param buf buffer where the SDP will be stored (must be allocated by
 *            the caller)
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 * @param size the size of the buffer
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 * @return 0 if OK, AVERROR_xxx on error
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 */
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int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
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/**
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 * Return a positive value if the given filename has one of the given
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 * extensions, 0 otherwise.
 *
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 * @param filename   file name to check against the given extensions
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 * @param extensions a comma-separated list of filename extensions
 */
int av_match_ext(const char *filename, const char *extensions);

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/**
 * Test if the given container can store a codec.
 *
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 * @param ofmt           container to check for compatibility
 * @param codec_id       codec to potentially store in container
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 * @param std_compliance standards compliance level, one of FF_COMPLIANCE_*
 *
 * @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
 *         A negative number if this information is not available.
 */
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int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id,
                         int std_compliance);
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/**
 * @defgroup riff_fourcc RIFF FourCCs
 * @{
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 * Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs. The tables are
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 * meant to be passed to av_codec_get_id()/av_codec_get_tag() as in the
 * following code:
 * @code
 * uint32_t tag = MKTAG('H', '2', '6', '4');
 * const struct AVCodecTag *table[] = { avformat_get_riff_video_tags(), 0 };
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 * enum AVCodecID id = av_codec_get_id(table, tag);
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 * @endcode
 */
/**
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 * @return the table mapping RIFF FourCCs for video to libavcodec AVCodecID.
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 */
const struct AVCodecTag *avformat_get_riff_video_tags(void);
/**
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 * @return the table mapping RIFF FourCCs for audio to AVCodecID.
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 */
const struct AVCodecTag *avformat_get_riff_audio_tags(void);
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/**
 * @return the table mapping MOV FourCCs for video to libavcodec AVCodecID.
 */
const struct AVCodecTag *avformat_get_mov_video_tags(void);
/**
 * @return the table mapping MOV FourCCs for audio to AVCodecID.
 */
const struct AVCodecTag *avformat_get_mov_audio_tags(void);
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/**
 * @}
 */

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/**
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 * Guess the sample aspect ratio of a frame, based on both the stream and the
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 * frame aspect ratio.
 *
 * Since the frame aspect ratio is set by the codec but the stream aspect ratio
 * is set by the demuxer, these two may not be equal. This function tries to
 * return the value that you should use if you would like to display the frame.
 *
 * Basic logic is to use the stream aspect ratio if it is set to something sane
 * otherwise use the frame aspect ratio. This way a container setting, which is
 * usually easy to modify can override the coded value in the frames.
 *
 * @param format the format context which the stream is part of
 * @param stream the stream which the frame is part of
 * @param frame the frame with the aspect ratio to be determined
 * @return the guessed (valid) sample_aspect_ratio, 0/1 if no idea
 */
AVRational av_guess_sample_aspect_ratio(AVFormatContext *format, AVStream *stream, AVFrame *frame);

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/**
 * Guess the frame rate, based on both the container and codec information.
 *
 * @param ctx the format context which the stream is part of
 * @param stream the stream which the frame is part of
 * @param frame the frame for which the frame rate should be determined, may be NULL
 * @return the guessed (valid) frame rate, 0/1 if no idea
 */
AVRational av_guess_frame_rate(AVFormatContext *ctx, AVStream *stream, AVFrame *frame);

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/**
 * Check if the stream st contained in s is matched by the stream specifier
 * spec.
 *
 * See the "stream specifiers" chapter in the documentation for the syntax
 * of spec.
 *
 * @return  >0 if st is matched by spec;
 *          0  if st is not matched by spec;
 *          AVERROR code if spec is invalid
 *
 * @note  A stream specifier can match several streams in the format.
 */
int avformat_match_stream_specifier(AVFormatContext *s, AVStream *st,
                                    const char *spec);

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int avformat_queue_attached_pictures(AVFormatContext *s);
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/**
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 * @}
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 */

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#endif /* AVFORMAT_AVFORMAT_H */