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FFmpeg/libavformat/avformat.h
Michael Niedermayer 018601dbf9 lavf: inject sample skip side data when requested by the demuxer 
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2012-07-12 20:32:03 +02:00

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/*
* copyright (c) 2001 Fabrice Bellard
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* 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
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVFORMAT_AVFORMAT_H
#define AVFORMAT_AVFORMAT_H
/**
* @file
* @ingroup libavf
* Main libavformat public API header
*/
/**
* @defgroup libavf I/O and Muxing/Demuxing Library
* @{
*
* 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
* most Libavformat structures, its size is not part of public ABI, so it cannot be
* 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).
*
* @section lavf_options Passing options to (de)muxers
* Lavf allows to configure muxers and demuxers using the @ref avoptions
* 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.
*
* @defgroup lavf_decoding Demuxing
* @{
* Demuxers read a media file and split it into chunks of data (@em packets). A
* @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
* 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.
*
* 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
*
* 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
* 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.
*
* The packet data belongs to the demuxer and is invalid after the next call to
* av_read_frame(). The user must free the packet with av_free_packet() before
* calling av_read_frame() again or closing the file.
*
* @section lavf_decoding_seek Seeking
* @}
*
* @defgroup lavf_encoding Muxing
* @{
* @}
*
* @defgroup lavf_io I/O Read/Write
* @{
* @}
*
* @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
* @{
* @}
* @}
*
*/
#include <time.h>
#include <stdio.h> /* FILE */
#include "libavcodec/avcodec.h"
#include "libavutil/dict.h"
#include "libavutil/log.h"
#include "avio.h"
#include "libavformat/version.h"
#if FF_API_AV_GETTIME
#include "libavutil/time.h"
#endif
struct AVFormatContext;
/**
* @defgroup metadata_api Public Metadata API
* @{
* @ingroup libavf
* The metadata API allows libavformat to export metadata tags to a client
* 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
* using the @ref lavu_dict "AVDictionary" API. Like all strings in FFmpeg,
* metadata is assumed to be UTF-8 encoded Unicode. Note that metadata
* exported by demuxers isn't checked to be valid UTF-8 in most cases.
*
* Important concepts to keep in mind:
* - Keys are unique; there can never be 2 tags with the same key. This is
* 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.
* - Metadata is flat, not hierarchical; there are no subtags. If you
* 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.
* - Several modifiers can be applied to the tag name. This is done by
* 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.
* - language -- a tag whose value is localized for a particular language
* 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.
* - sorting -- a modified version of a tag that should be used for
* sorting will have '-sort' appended. E.g. artist="The Beatles",
* artist-sort="Beatles, The".
*
* - Demuxers attempt to export metadata in a generic format, however tags
* with no generic equivalents are left as they are stored in the container.
* Follows a list of generic tag names:
*
@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
*
* Look in the examples section for an application example how to use the Metadata API.
*
* @}
*/
/* packet functions */
/**
* Allocate and read the payload of a packet and initialize its
* fields with default values.
*
* @param pkt packet
* @param size desired payload size
* @return >0 (read size) if OK, AVERROR_xxx otherwise
*/
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size);
/**
* Read data and append it to the current content of the AVPacket.
* If pkt->size is 0 this is identical to av_get_packet.
* 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.
*
* @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.
*/
int av_append_packet(AVIOContext *s, AVPacket *pkt, int size);
/*************************************************/
/* fractional numbers for exact pts handling */
/**
* The exact value of the fractional number is: 'val + num / den'.
* num is assumed to be 0 <= num < den.
*/
typedef struct AVFrac {
int64_t val, num, den;
} AVFrac;
/*************************************************/
/* input/output formats */
struct AVCodecTag;
/**
* This structure contains the data a format has to probe a file.
*/
typedef struct AVProbeData {
const char *filename;
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 */
} AVProbeData;
#define AVPROBE_SCORE_MAX 100 ///< maximum score, half of that is used for file-extension-based detection
#define AVPROBE_PADDING_SIZE 32 ///< extra allocated bytes at the end of the probe buffer
/// Demuxer will use avio_open, no opened file should be provided by the caller.
#define AVFMT_NOFILE 0x0001
#define AVFMT_NEEDNUMBER 0x0002 /**< Needs '%d' in filename. */
#define AVFMT_SHOW_IDS 0x0008 /**< Show format stream IDs numbers. */
#define AVFMT_RAWPICTURE 0x0020 /**< Format wants AVPicture structure for
raw picture data. */
#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. */
#define AVFMT_TS_DISCONT 0x0200 /**< Format allows timestamp discontinuities. Note, muxers always require valid (monotone) timestamps */
#define AVFMT_VARIABLE_FPS 0x0400 /**< Format allows variable fps. */
#define AVFMT_NODIMENSIONS 0x0800 /**< Format does not need width/height */
#define AVFMT_NOSTREAMS 0x1000 /**< Format does not require any streams */
#define AVFMT_NOBINSEARCH 0x2000 /**< Format does not allow to fallback to binary search via read_timestamp */
#define AVFMT_NOGENSEARCH 0x4000 /**< Format does not allow to fallback to generic search */
#define AVFMT_NO_BYTE_SEEK 0x8000 /**< Format does not allow seeking by bytes */
#define AVFMT_ALLOW_FLUSH 0x10000 /**< Format allows flushing. If not set, the muxer will not receive a NULL packet in the write_packet function. */
#if LIBAVFORMAT_VERSION_MAJOR <= 54
#define AVFMT_TS_NONSTRICT 0x8020000 //we try to be compatible to the ABIs of ffmpeg and major forks
#else
#define AVFMT_TS_NONSTRICT 0x20000
#endif
/**< Format does not require strictly
increasing timestamps, but they must
still be monotonic */
#define AVFMT_SEEK_TO_PTS 0x4000000 /**< Seeking is based on PTS */
/**
* @addtogroup lavf_encoding
* @{
*/
typedef struct AVOutputFormat {
const char *name;
/**
* Descriptive name for the format, meant to be more human-readable
* than name. You should use the NULL_IF_CONFIG_SMALL() macro
* to define it.
*/
const char *long_name;
const char *mime_type;
const char *extensions; /**< comma-separated filename extensions */
/* output support */
enum CodecID audio_codec; /**< default audio codec */
enum CodecID video_codec; /**< default video codec */
enum CodecID subtitle_codec; /**< default subtitle codec */
/**
* can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_RAWPICTURE,
* AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,
* AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,
* AVFMT_TS_NONSTRICT
*/
int flags;
/**
* List of supported codec_id-codec_tag pairs, ordered by "better
* choice first". The arrays are all terminated by CODEC_ID_NONE.
*/
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;
/**
* size of private data so that it can be allocated in the wrapper
*/
int priv_data_size;
int (*write_header)(struct AVFormatContext *);
/**
* 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.
*/
int (*write_packet)(struct AVFormatContext *, AVPacket *pkt);
int (*write_trailer)(struct AVFormatContext *);
/**
* Currently only used to set pixel format if not YUV420P.
*/
int (*interleave_packet)(struct AVFormatContext *, AVPacket *out,
AVPacket *in, int flush);
/**
* 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.
*/
int (*query_codec)(enum CodecID id, int std_compliance);
void (*get_output_timestamp)(struct AVFormatContext *s, int stream,
int64_t *dts, int64_t *wall);
} AVOutputFormat;
/**
* @}
*/
/**
* @addtogroup lavf_decoding
* @{
*/
typedef struct AVInputFormat {
/**
* A comma separated list of short names for the format. New names
* may be appended with a minor bump.
*/
const char *name;
/**
* Descriptive name for the format, meant to be more human-readable
* than name. You should use the NULL_IF_CONFIG_SMALL() macro
* to define it.
*/
const char *long_name;
/**
* Can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER, AVFMT_SHOW_IDS,
* AVFMT_GENERIC_INDEX, AVFMT_TS_DISCONT, AVFMT_NOBINSEARCH,
* AVFMT_NOGENSEARCH, AVFMT_NO_BYTE_SEEK, AVFMT_SEEK_TO_PTS.
*/
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
/*****************************************************************
* 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;
/**
* Raw demuxers store their codec ID here.
*/
int raw_codec_id;
/**
* Size of private data so that it can be allocated in the wrapper.
*/
int priv_data_size;
/**
* Tell if a given file has a chance of being parsed as this format.
* 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.
*/
int (*read_probe)(AVProbeData *);
/**
* Read the format header and initialize the AVFormatContext
* structure. Return 0 if OK. Only used in raw format right
* now. 'avformat_new_stream' should be called to create new streams.
*/
int (*read_header)(struct AVFormatContext *);
/**
* Read one packet and put it in 'pkt'. pts and flags are also
* set. 'avformat_new_stream' can be called only if the flag
* AVFMTCTX_NOHEADER is used and only in the calling thread (not in a
* background thread).
* @return 0 on success, < 0 on error.
* When returning an error, pkt must not have been allocated
* or must be freed before returning
*/
int (*read_packet)(struct AVFormatContext *, AVPacket *pkt);
/**
* Close the stream. The AVFormatContext and AVStreams are not
* freed by this function
*/
int (*read_close)(struct AVFormatContext *);
/**
* Seek to a given timestamp relative to the frames in
* stream component stream_index.
* @param stream_index Must not be -1.
* @param flags Selects which direction should be preferred if no exact
* match is available.
* @return >= 0 on success (but not necessarily the new offset)
*/
int (*read_seek)(struct AVFormatContext *,
int stream_index, int64_t timestamp, int flags);
/**
* Get the next timestamp in stream[stream_index].time_base units.
* @return the timestamp or AV_NOPTS_VALUE if an error occurred
*/
int64_t (*read_timestamp)(struct AVFormatContext *s, int stream_index,
int64_t *pos, int64_t pos_limit);
/**
* Start/resume playing - only meaningful if using a network-based format
* (RTSP).
*/
int (*read_play)(struct AVFormatContext *);
/**
* Pause playing - only meaningful if using a network-based format
* (RTSP).
*/
int (*read_pause)(struct AVFormatContext *);
/**
* Seek to timestamp ts.
* 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.
*/
int (*read_seek2)(struct AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
} AVInputFormat;
/**
* @}
*/
enum AVStreamParseType {
AVSTREAM_PARSE_NONE,
AVSTREAM_PARSE_FULL, /**< full parsing and repack */
AVSTREAM_PARSE_HEADERS, /**< Only parse headers, do not repack. */
AVSTREAM_PARSE_TIMESTAMPS, /**< full parsing and interpolation of timestamps for frames not starting on a packet boundary */
AVSTREAM_PARSE_FULL_ONCE, /**< full parsing and repack of the first frame only, only implemented for H.264 currently */
AVSTREAM_PARSE_FULL_RAW=MKTAG(0,'R','A','W'), /**< full parsing and repack with timestamp generation for raw */
};
typedef struct AVIndexEntry {
int64_t pos;
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
*/
#define AVINDEX_KEYFRAME 0x0001
int flags:2;
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. */
} AVIndexEntry;
#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
/**
* 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.
*/
#define AV_DISPOSITION_FORCED 0x0040
#define AV_DISPOSITION_HEARING_IMPAIRED 0x0080 /**< stream for hearing impaired audiences */
#define AV_DISPOSITION_VISUAL_IMPAIRED 0x0100 /**< stream for visual impaired audiences */
#define AV_DISPOSITION_CLEAN_EFFECTS 0x0200 /**< stream without voice */
/**
* 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
/**
* Stream structure.
* New fields can be added to the end with minor version bumps.
* Removal, reordering and changes to existing fields require a major
* version bump.
* sizeof(AVStream) must not be used outside libav*.
*/
typedef struct AVStream {
int index; /**< stream index in AVFormatContext */
/**
* Format-specific stream ID.
* decoding: set by libavformat
* encoding: set by the user
*/
int id;
/**
* 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;
/**
* 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.
*/
AVRational r_frame_rate;
void *priv_data;
/**
* encoding: pts generation when outputting stream
*/
struct AVFrac pts;
/**
* This is the fundamental unit of time (in seconds) in terms
* of which frame timestamps are represented.
*
* decoding: set by libavformat
* encoding: set by libavformat in av_write_header. The muxer may use the
* user-provided value of @ref AVCodecContext.time_base "codec->time_base"
* as a hint.
*/
AVRational time_base;
/**
* Decoding: pts of the first frame of the stream in presentation order, in stream time base.
* Only set this if you are absolutely 100% sure that the value you set
* it to really is the pts of the first frame.
* This may be undefined (AV_NOPTS_VALUE).
* @note The ASF header does NOT contain a correct start_time the ASF
* demuxer must NOT set this.
*/
int64_t start_time;
/**
* Decoding: duration of the stream, in stream time base.
* If a source file does not specify a duration, but does specify
* a bitrate, this value will be estimated from bitrate and file size.
*/
int64_t duration;
int64_t nb_frames; ///< number of frames in this stream if known or 0
int disposition; /**< AV_DISPOSITION_* bit field */
enum AVDiscard discard; ///< Selects which packets can be discarded at will and do not need to be demuxed.
/**
* sample aspect ratio (0 if unknown)
* - encoding: Set by user.
* - decoding: Set by libavformat.
*/
AVRational sample_aspect_ratio;
AVDictionary *metadata;
/**
* Average framerate
*/
AVRational avg_frame_rate;
/**
* 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;
/*****************************************************************
* 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.
*****************************************************************
*/
/**
* Stream information used internally by av_find_stream_info()
*/
#define MAX_STD_TIMEBASES (60*12+6)
struct {
int64_t last_dts;
int64_t duration_gcd;
int duration_count;
double duration_error[2][2][MAX_STD_TIMEBASES];
int64_t codec_info_duration;
int nb_decoded_frames;
int found_decoder;
} *info;
int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */
// 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 reference_dts;
int64_t first_dts;
int64_t cur_dts;
int64_t last_IP_pts;
int last_IP_duration;
/**
* Number of packets to buffer for codec probing
*/
#define MAX_PROBE_PACKETS 2500
int probe_packets;
/**
* Number of frames that have been demuxed during av_find_stream_info()
*/
int codec_info_nb_frames;
/**
* 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;
/* av_read_frame() support */
enum AVStreamParseType need_parsing;
struct AVCodecParserContext *parser;
/**
* 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;
/**
* flag to indicate that probing is requested
* NOT PART OF PUBLIC API
*/
int request_probe;
/**
* Indicates that everything up to the next keyframe
* should be discarded.
*/
int skip_to_keyframe;
/**
* Number of samples to skip at the start of the frame decoded from the next packet.
*/
int skip_samples;
} AVStream;
#define AV_PROGRAM_RUNNING 1
/**
* New fields can be added to the end with minor version bumps.
* Removal, reordering and changes to existing fields require a major
* version bump.
* sizeof(AVProgram) must not be used outside libav*.
*/
typedef struct AVProgram {
int id;
int flags;
enum AVDiscard discard; ///< selects which program to discard and which to feed to the caller
unsigned int *stream_index;
unsigned int nb_stream_indexes;
AVDictionary *metadata;
int program_num;
int pmt_pid;
int pcr_pid;
} AVProgram;
#define AVFMTCTX_NOHEADER 0x0001 /**< signal that no header is present
(streams are added dynamically) */
typedef struct AVChapter {
int id; ///< unique ID to identify the chapter
AVRational time_base; ///< time base in which the start/end timestamps are specified
int64_t start, end; ///< chapter start/end time in time_base units
AVDictionary *metadata;
} AVChapter;
/**
* 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)
};
/**
* Format I/O context.
* New fields can be added to the end with minor version bumps.
* Removal, reordering and changes to existing fields require a major
* version bump.
* sizeof(AVFormatContext) must not be used outside libav*, use
* avformat_alloc_context() to create an AVFormatContext.
*/
typedef struct AVFormatContext {
/**
* A class for logging and AVOptions. Set by avformat_alloc_context().
* Exports (de)muxer private options if they exist.
*/
const AVClass *av_class;
/**
* Can only be iformat or oformat, not both at the same time.
*
* decoding: set by avformat_open_input().
* encoding: set by the user.
*/
struct AVInputFormat *iformat;
struct AVOutputFormat *oformat;
/**
* Format private data. This is an AVOptions-enabled struct
* if and only if iformat/oformat.priv_class is not NULL.
*/
void *priv_data;
/**
* I/O context.
*
* decoding: either set by the user before avformat_open_input() (then
* the user must close it manually) or set by avformat_open_input().
* encoding: set by the user.
*
* 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.
*/
AVIOContext *pb;
/* stream info */
int ctx_flags; /**< Format-specific flags, see AVFMTCTX_xx */
/**
* A list of all streams in the file. New streams are created with
* avformat_new_stream().
*
* decoding: 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().
* encoding: streams are created by the user before avformat_write_header().
*/
unsigned int nb_streams;
AVStream **streams;
char filename[1024]; /**< input or output filename */
/**
* Decoding: position of the first frame of the component, in
* AV_TIME_BASE fractional seconds. NEVER set this value directly:
* It is deduced from the AVStream values.
*/
int64_t start_time;
/**
* Decoding: duration of the stream, in AV_TIME_BASE fractional
* seconds. Only set this value if you know none of the individual stream
* durations and also do not set any of them. This is deduced from the
* AVStream values if not set.
*/
int64_t duration;
/**
* Decoding: total stream bitrate in bit/s, 0 if not
* available. Never set it directly if the file_size and the
* duration are known as FFmpeg can compute it automatically.
*/
int bit_rate;
unsigned int packet_size;
int max_delay;
int flags;
#define AVFMT_FLAG_GENPTS 0x0001 ///< Generate missing pts even if it requires parsing future frames.
#define AVFMT_FLAG_IGNIDX 0x0002 ///< Ignore index.
#define AVFMT_FLAG_NONBLOCK 0x0004 ///< Do not block when reading packets from input.
#define AVFMT_FLAG_IGNDTS 0x0008 ///< Ignore DTS on frames that contain both DTS & PTS
#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
#define AVFMT_FLAG_CUSTOM_IO 0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
#define AVFMT_FLAG_DISCARD_CORRUPT 0x0100 ///< Discard frames marked corrupted
#define AVFMT_FLAG_MP4A_LATM 0x8000 ///< Enable RTP MP4A-LATM payload
#define AVFMT_FLAG_SORT_DTS 0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
#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)
#define AVFMT_FLAG_KEEP_SIDE_DATA 0x40000 ///< Don't merge side data but keep it separate.
/**
* decoding: size of data to probe; encoding: unused.
*/
unsigned int probesize;
/**
* decoding: maximum time (in AV_TIME_BASE units) during which the input should
* be analyzed in avformat_find_stream_info().
*/
int max_analyze_duration;
const uint8_t *key;
int keylen;
unsigned int nb_programs;
AVProgram **programs;
/**
* Forced video codec_id.
* Demuxing: Set by user.
*/
enum CodecID video_codec_id;
/**
* Forced audio codec_id.
* Demuxing: Set by user.
*/
enum CodecID audio_codec_id;
/**
* Forced subtitle codec_id.
* Demuxing: Set by user.
*/
enum CodecID subtitle_codec_id;
/**
* 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
* needed to maintain a smaller size. This can lead to slower or less
* accurate seeking (depends on demuxer).
* Demuxers for which a full in-memory index is mandatory will ignore
* this.
* muxing : unused
* demuxing: set by user
*/
unsigned int max_index_size;
/**
* Maximum amount of memory in bytes to use for buffering frames
* obtained from realtime capture devices.
*/
unsigned int max_picture_buffer;
unsigned int nb_chapters;
AVChapter **chapters;
AVDictionary *metadata;
/**
* Start time of the stream in real world time, in microseconds
* since the unix epoch (00:00 1st January 1970). That is, pts=0
* in the stream was captured at this real world time.
* - encoding: Set by user.
* - decoding: Unused.
*/
int64_t start_time_realtime;
/**
* decoding: number of frames used to probe fps
*/
int fps_probe_size;
/**
* Error recognition; higher values will detect more errors but may
* misdetect some more or less valid parts as errors.
* - encoding: unused
* - decoding: Set by user.
*/
int error_recognition;
/**
* Custom interrupt callbacks for the I/O layer.
*
* decoding: set by the user before avformat_open_input().
* encoding: set by the user before avformat_write_header()
* (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;
/**
* Flags to enable debugging.
*/
int debug;
#define FF_FDEBUG_TS 0x0001
/**
* Transport stream id.
* This will be moved into demuxer private options. Thus no API/ABI compatibility
*/
int ts_id;
/**
* 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;
/**
* 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;
/*****************************************************************
* 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.
*****************************************************************
*/
/**
* This buffer is only needed when packets were already buffered but
* not decoded, for example to get the codec parameters in MPEG
* streams.
*/
struct AVPacketList *packet_buffer;
struct AVPacketList *packet_buffer_end;
/* av_seek_frame() support */
int64_t data_offset; /**< offset of the first packet */
/**
* Raw packets from the demuxer, prior to parsing and decoding.
* This buffer is used for buffering packets until the codec can
* be identified, as parsing cannot be done without knowing the
* codec.
*/
struct AVPacketList *raw_packet_buffer;
struct AVPacketList *raw_packet_buffer_end;
/**
* Packets split by the parser get queued here.
*/
struct AVPacketList *parse_queue;
struct AVPacketList *parse_queue_end;
/**
* Remaining size available for raw_packet_buffer, in bytes.
*/
#define RAW_PACKET_BUFFER_SIZE 2500000
int raw_packet_buffer_remaining_size;
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.
*/
enum AVDurationEstimationMethod duration_estimation_method;
} AVFormatContext;
/**
* Returns the method used to set ctx->duration.
*
* @return AVFMT_DURATION_FROM_PTS, AVFMT_DURATION_FROM_STREAM, or AVFMT_DURATION_FROM_BITRATE.
*/
enum AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext* ctx);
typedef struct AVPacketList {
AVPacket pkt;
struct AVPacketList *next;
} AVPacketList;
/**
* @defgroup lavf_core Core functions
* @ingroup libavf
*
* Functions for querying libavformat capabilities, allocating core structures,
* etc.
* @{
*/
/**
* Return the LIBAVFORMAT_VERSION_INT constant.
*/
unsigned avformat_version(void);
/**
* Return the libavformat build-time configuration.
*/
const char *avformat_configuration(void);
/**
* Return the libavformat license.
*/
const char *avformat_license(void);
/**
* 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.
*
* @see av_register_input_format()
* @see av_register_output_format()
* @see av_register_protocol()
*/
void av_register_all(void);
void av_register_input_format(AVInputFormat *format);
void av_register_output_format(AVOutputFormat *format);
/**
* Do global initialization of network components. This is optional,
* but recommended, since it avoids the overhead of implicitly
* doing the setup for each session.
*
* Calling this function will become mandatory if using network
* protocols at some major version bump.
*/
int avformat_network_init(void);
/**
* Undo the initialization done by avformat_network_init.
*/
int avformat_network_deinit(void);
/**
* If f is NULL, returns the first registered input format,
* if f is non-NULL, returns the next registered input format after f
* or NULL if f is the last one.
*/
AVInputFormat *av_iformat_next(AVInputFormat *f);
/**
* If f is NULL, returns the first registered output format,
* if f is non-NULL, returns the next registered output format after f
* or NULL if f is the last one.
*/
AVOutputFormat *av_oformat_next(AVOutputFormat *f);
/**
* 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);
/**
* Free an AVFormatContext and all its streams.
* @param s context to free
*/
void avformat_free_context(AVFormatContext *s);
/**
* Get the AVClass for AVFormatContext. It can be used in combination with
* AV_OPT_SEARCH_FAKE_OBJ for examining options.
*
* @see av_opt_find().
*/
const AVClass *avformat_get_class(void);
/**
* Add a new stream to a media file.
*
* 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().
*
* @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.
*/
AVStream *avformat_new_stream(AVFormatContext *s, AVCodec *c);
AVProgram *av_new_program(AVFormatContext *s, int id);
/**
* @}
*/
#if FF_API_PKT_DUMP
attribute_deprecated void av_pkt_dump(FILE *f, AVPacket *pkt, int dump_payload);
attribute_deprecated void av_pkt_dump_log(void *avcl, int level, AVPacket *pkt,
int dump_payload);
#endif
#if FF_API_ALLOC_OUTPUT_CONTEXT
/**
* @deprecated deprecated in favor of avformat_alloc_output_context2()
*/
attribute_deprecated
AVFormatContext *avformat_alloc_output_context(const char *format,
AVOutputFormat *oformat,
const char *filename);
#endif
/**
* 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);
/**
* @addtogroup lavf_decoding
* @{
*/
/**
* Find AVInputFormat based on the short name of the input format.
*/
AVInputFormat *av_find_input_format(const char *short_name);
/**
* Guess the file format.
*
* @param is_opened Whether the file is already opened; determines whether
* demuxers with or without AVFMT_NOFILE are probed.
*/
AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened);
/**
* 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_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
* to retry with a larger probe buffer.
*/
AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max);
/**
* 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);
/**
* 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)
* @return 0 in case of success, a negative value corresponding to an
* AVERROR code otherwise
*/
int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
const char *filename, void *logctx,
unsigned int offset, unsigned int max_probe_size);
/**
* Open an input stream and read the header. The codecs are not opened.
* The stream must be closed with av_close_input_file().
*
* @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);
attribute_deprecated
int av_demuxer_open(AVFormatContext *ic);
#if FF_API_FORMAT_PARAMETERS
/**
* 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
* @return >=0 if OK, AVERROR_xxx on error
* @todo Let the user decide somehow what information is needed so that
* we do not waste time getting stuff the user does not need.
*
* @deprecated use avformat_find_stream_info.
*/
attribute_deprecated
int av_find_stream_info(AVFormatContext *ic);
#endif
/**
* 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);
/**
* 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);
/**
* 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);
#if FF_API_READ_PACKET
/**
* @deprecated use AVFMT_FLAG_NOFILLIN | AVFMT_FLAG_NOPARSE to read raw
* unprocessed packets
*
* Read a transport packet from a media file.
*
* This function is obsolete and should never be used.
* Use av_read_frame() instead.
*
* @param s media file handle
* @param pkt is filled
* @return 0 if OK, AVERROR_xxx on error
*/
attribute_deprecated
int av_read_packet(AVFormatContext *s, AVPacket *pkt);
#endif
/**
* Return the next frame of a stream.
* 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.
*
* The returned packet is valid
* until the next av_read_frame() or until av_close_input_file() and
* must be freed with av_free_packet. For video, the packet contains
* 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.
*
* pkt->pts, pkt->dts and pkt->duration are always set to correct
* values in AVStream.time_base units (and guessed if the format cannot
* 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
* decompress the payload.
*
* @return 0 if OK, < 0 on error or end of file
*/
int av_read_frame(AVFormatContext *s, AVPacket *pkt);
/**
* Seek to the keyframe at timestamp.
* 'timestamp' in 'stream_index'.
* @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.
* @param timestamp Timestamp in AVStream.time_base units
* or, if no stream is specified, in AV_TIME_BASE units.
* @param flags flags which select direction and seeking mode
* @return >= 0 on success
*/
int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp,
int flags);
/**
* Seek to timestamp ts.
* 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.
*
* If flags contain AVSEEK_FLAG_BYTE, then all timestamps are in bytes and
* are the file position (this may not be supported by all demuxers).
* If flags contain AVSEEK_FLAG_FRAME, then all timestamps are in frames
* in the stream with stream_index (this may not be supported by all demuxers).
* 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
* keyframes (this may not be supported by all demuxers).
*
* @param stream_index index of the stream which is used as time base reference
* @param min_ts smallest acceptable timestamp
* @param ts target timestamp
* @param max_ts largest acceptable timestamp
* @param flags flags
* @return >=0 on success, error code otherwise
*
* @note This is part of the new seek API which is still under construction.
* Thus do not use this yet. It may change at any time, do not expect
* ABI compatibility yet!
*/
int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
/**
* Start playing a network-based stream (e.g. RTSP stream) at the
* current position.
*/
int av_read_play(AVFormatContext *s);
/**
* Pause a network-based stream (e.g. RTSP stream).
*
* Use av_read_play() to resume it.
*/
int av_read_pause(AVFormatContext *s);
#if FF_API_CLOSE_INPUT_FILE
/**
* @deprecated use avformat_close_input()
* Close a media file (but not its codecs).
*
* @param s media file handle
*/
attribute_deprecated
void av_close_input_file(AVFormatContext *s);
#endif
/**
* Close an opened input AVFormatContext. Free it and all its contents
* and set *s to NULL.
*/
void avformat_close_input(AVFormatContext **s);
/**
* @}
*/
#if FF_API_NEW_STREAM
/**
* Add a new stream to a media file.
*
* Can only be called in the read_header() function. If the flag
* AVFMTCTX_NOHEADER is in the format context, then new streams
* can be added in read_packet too.
*
* @param s media file handle
* @param id file-format-dependent stream ID
*/
attribute_deprecated
AVStream *av_new_stream(AVFormatContext *s, int id);
#endif
#if FF_API_SET_PTS_INFO
/**
* @deprecated this function is not supposed to be called outside of lavf
*/
attribute_deprecated
void av_set_pts_info(AVStream *s, int pts_wrap_bits,
unsigned int pts_num, unsigned int pts_den);
#endif
#define AVSEEK_FLAG_BACKWARD 1 ///< seek backward
#define AVSEEK_FLAG_BYTE 2 ///< seeking based on position in bytes
#define AVSEEK_FLAG_ANY 4 ///< seek to any frame, even non-keyframes
#define AVSEEK_FLAG_FRAME 8 ///< seeking based on frame number
/**
* @addtogroup lavf_encoding
* @{
*/
/**
* 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;
* Its pb field must be set to an already openened AVIOContext.
* @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);
/**
* Write a packet to an output media file.
*
* The packet shall contain one audio or video frame.
* The packet must be correctly interleaved according to the container
* specification, if not then av_interleaved_write_frame must be used.
*
* @param s media file handle
* @param pkt The packet, which contains the stream_index, buf/buf_size,
* dts/pts, ...
* This 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.
* @return < 0 on error, = 0 if OK, 1 if flushed and there is no more data to flush
*/
int av_write_frame(AVFormatContext *s, AVPacket *pkt);
/**
* Write a packet to an output media file ensuring correct interleaving.
*
* The packet must contain one audio or video frame.
* If the packets are already correctly interleaved, the application should
* call av_write_frame() instead as it is slightly faster. It is also important
* to keep in mind that completely non-interleaved input will need huge amounts
* of memory to interleave with this, so it is preferable to interleave at the
* demuxer level.
*
* @param s media file handle
* @param pkt The packet containing the data to be written. Libavformat takes
* ownership of the data and will free it when it sees fit using the packet's
* This can be NULL (at any time, not just at the end), to flush the
* interleaving queues.
* @ref AVPacket.destruct "destruct" field. The caller must not access the data
* after this function returns, as it may already be freed.
* Packet's @ref AVPacket.stream_index "stream_index" field must be set to the
* index of the corresponding stream in @ref AVFormatContext.streams
* "s.streams".
* It is very strongly recommended that timing information (@ref AVPacket.pts
* "pts", @ref AVPacket.dts "dts" @ref AVPacket.duration "duration") is set to
* correct values.
*
* @return 0 on success, a negative AVERROR on error.
*/
int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
#if FF_API_INTERLEAVE_PACKET
/**
* @deprecated this function was never meant to be called by the user
* programs.
*/
attribute_deprecated
int av_interleave_packet_per_dts(AVFormatContext *s, AVPacket *out,
AVPacket *pkt, int flush);
#endif
/**
* Write the stream trailer to an output media file and free the
* file private data.
*
* May only be called after a successful call to av_write_header.
*
* @param s media file handle
* @return 0 if OK, AVERROR_xxx on error
*/
int av_write_trailer(AVFormatContext *s);
/**
* 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.
*/
enum CodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
const char *filename, const char *mime_type,
enum AVMediaType type);
/**
* 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
* @param dts[out] DTS of the last packet output for the stream, in stream
* time_base units
* @param wall[out] absolute time when that packet whas output,
* 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);
/**
* @}
*/
/**
* @defgroup lavf_misc Utility functions
* @ingroup libavf
* @{
*
* Miscellaneous utility functions related to both muxing and demuxing
* (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
*/
void av_hex_dump(FILE *f, uint8_t *buf, int size);
/**
* 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
*/
void av_hex_dump_log(void *avcl, int level, uint8_t *buf, int size);
/**
* 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
*/
void av_pkt_dump2(FILE *f, AVPacket *pkt, int dump_payload, AVStream *st);
/**
* 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
*/
void av_pkt_dump_log2(void *avcl, int level, AVPacket *pkt, int dump_payload,
AVStream *st);
/**
* Get the CodecID for the given codec tag tag.
* If no codec id is found returns CODEC_ID_NONE.
*
* @param tags list of supported codec_id-codec_tag pairs, as stored
* in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
*/
enum CodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
/**
* 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
*/
unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum CodecID id);
int av_find_default_stream_index(AVFormatContext *s);
/**
* Get the index for a specific timestamp.
* @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);
void av_dump_format(AVFormatContext *ic,
int index,
const char *url,
int is_output);
/**
* Return in 'buf' the path with '%d' replaced by a number.
*
* 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
* @param number frame number
* @return 0 if OK, -1 on format error
*/
int av_get_frame_filename(char *buf, int buf_size,
const char *path, int number);
/**
* Check whether filename actually is a numbered sequence generator.
*
* @param filename possible numbered sequence string
* @return 1 if a valid numbered sequence string, 0 otherwise
*/
int av_filename_number_test(const char *filename);
/**
* Generate an SDP for an RTP session.
*
* @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)
* must contain only one AVStream.
* @param n_files number of AVCodecContexts contained in ac
* @param buf buffer where the SDP will be stored (must be allocated by
* the caller)
* @param size the size of the buffer
* @return 0 if OK, AVERROR_xxx on error
*/
int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
/**
* Return a positive value if the given filename has one of the given
* extensions, 0 otherwise.
*
* @param extensions a comma-separated list of filename extensions
*/
int av_match_ext(const char *filename, const char *extensions);
/**
* Test if the given container can store a codec.
*
* @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.
*/
int avformat_query_codec(AVOutputFormat *ofmt, enum CodecID codec_id, int std_compliance);
/**
* @defgroup riff_fourcc RIFF FourCCs
* @{
* Get the tables mapping RIFF FourCCs to libavcodec CodecIDs. The tables are
* 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 };
* enum CodecID id = av_codec_get_id(table, tag);
* @endcode
*/
/**
* @return the table mapping RIFF FourCCs for video to libavcodec CodecID.
*/
const struct AVCodecTag *avformat_get_riff_video_tags(void);
/**
* @return the table mapping RIFF FourCCs for audio to CodecID.
*/
const struct AVCodecTag *avformat_get_riff_audio_tags(void);
/**
* Guesses the sample aspect ratio of a frame, based on both the stream and the
* 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);
/**
* @}
*/
/**
* @}
*/
#endif /* AVFORMAT_AVFORMAT_H */
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