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FFmpeg
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Format I/O context. More...
#include <avformat.h>
Public Attributes | |
| const AVClass * | av_class |
| A class for logging and AVOptions. More... | |
| struct AVInputFormat * | iformat |
| The input container format. More... | |
| struct AVOutputFormat * | oformat |
| The output container format. More... | |
| void * | priv_data |
| Format private data. More... | |
| AVIOContext * | pb |
| I/O context. More... | |
| int | ctx_flags |
| Flags signalling stream properties. More... | |
| unsigned int | nb_streams |
| Number of elements in AVFormatContext.streams. More... | |
| AVStream ** | streams |
| A list of all streams in the file. More... | |
| char * | url |
| input or output URL. More... | |
| int64_t | start_time |
| Position of the first frame of the component, in AV_TIME_BASE fractional seconds. More... | |
| int64_t | duration |
| Duration of the stream, in AV_TIME_BASE fractional seconds. More... | |
| int64_t | bit_rate |
| Total stream bitrate in bit/s, 0 if not available. More... | |
| unsigned int | packet_size |
| int | max_delay |
| int | flags |
| Flags modifying the (de)muxer behaviour. More... | |
| int64_t | probesize |
| Maximum size of the data read from input for determining the input container format. More... | |
| int64_t | max_analyze_duration |
| Maximum duration (in AV_TIME_BASE units) of the data read from input in avformat_find_stream_info(). More... | |
| const uint8_t * | key |
| int | keylen |
| unsigned int | nb_programs |
| AVProgram ** | programs |
| enum AVCodecID | video_codec_id |
| Forced video codec_id. More... | |
| enum AVCodecID | audio_codec_id |
| Forced audio codec_id. More... | |
| enum AVCodecID | subtitle_codec_id |
| Forced subtitle codec_id. More... | |
| unsigned int | max_index_size |
| Maximum amount of memory in bytes to use for the index of each stream. More... | |
| unsigned int | max_picture_buffer |
| Maximum amount of memory in bytes to use for buffering frames obtained from realtime capture devices. | |
| unsigned int | nb_chapters |
| Number of chapters in AVChapter array. More... | |
| AVChapter ** | chapters |
| AVDictionary * | metadata |
| Metadata that applies to the whole file. More... | |
| int64_t | start_time_realtime |
| Start time of the stream in real world time, in microseconds since the Unix epoch (00:00 1st January 1970). More... | |
| int | fps_probe_size |
| The number of frames used for determining the framerate in avformat_find_stream_info(). More... | |
| int | error_recognition |
| Error recognition; higher values will detect more errors but may misdetect some more or less valid parts as errors. More... | |
| AVIOInterruptCB | interrupt_callback |
| Custom interrupt callbacks for the I/O layer. More... | |
| int | debug |
| Flags to enable debugging. | |
| int64_t | max_interleave_delta |
| Maximum buffering duration for interleaving. More... | |
| int | strict_std_compliance |
| Allow non-standard and experimental extension. More... | |
| int | event_flags |
| Flags for the user to detect events happening on the file. More... | |
| int | max_ts_probe |
| Maximum number of packets to read while waiting for the first timestamp. More... | |
| int | avoid_negative_ts |
| Avoid negative timestamps during muxing. More... | |
| int | ts_id |
| Transport stream id. More... | |
| int | audio_preload |
| Audio preload in microseconds. More... | |
| int | max_chunk_duration |
| Max chunk time in microseconds. More... | |
| int | max_chunk_size |
| Max chunk size in bytes Note, not all formats support this and unpredictable things may happen if it is used when not supported. More... | |
| int | use_wallclock_as_timestamps |
| forces the use of wallclock timestamps as pts/dts of packets This has undefined results in the presence of B frames. More... | |
| int | avio_flags |
| avio flags, used to force AVIO_FLAG_DIRECT. More... | |
| enum AVDurationEstimationMethod | duration_estimation_method |
| The duration field can be estimated through various ways, and this field can be used to know how the duration was estimated. More... | |
| int64_t | skip_initial_bytes |
| Skip initial bytes when opening stream. More... | |
| unsigned int | correct_ts_overflow |
| Correct single timestamp overflows. More... | |
| int | seek2any |
| Force seeking to any (also non key) frames. More... | |
| int | flush_packets |
| Flush the I/O context after each packet. More... | |
| int | probe_score |
| format probing score. More... | |
| int | format_probesize |
| number of bytes to read maximally to identify format. More... | |
| char * | codec_whitelist |
| ',' separated list of allowed decoders. More... | |
| char * | format_whitelist |
| ',' separated list of allowed demuxers. More... | |
| AVFormatInternal * | internal |
| An opaque field for libavformat internal usage. More... | |
| int | io_repositioned |
| IO repositioned flag. More... | |
| AVCodec * | video_codec |
| Forced video codec. More... | |
| AVCodec * | audio_codec |
| Forced audio codec. More... | |
| AVCodec * | subtitle_codec |
| Forced subtitle codec. More... | |
| AVCodec * | data_codec |
| Forced data codec. More... | |
| int | metadata_header_padding |
| Number of bytes to be written as padding in a metadata header. More... | |
| void * | opaque |
| User data. More... | |
| av_format_control_message | control_message_cb |
| Callback used by devices to communicate with application. | |
| int64_t | output_ts_offset |
| Output timestamp offset, in microseconds. More... | |
| uint8_t * | dump_separator |
| dump format separator. More... | |
| enum AVCodecID | data_codec_id |
| Forced Data codec_id. More... | |
| char * | protocol_whitelist |
| ',' separated list of allowed protocols. More... | |
| int(* | io_open )(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags, AVDictionary **options) |
| A callback for opening new IO streams. More... | |
| void(* | io_close )(struct AVFormatContext *s, AVIOContext *pb) |
| A callback for closing the streams opened with AVFormatContext.io_open(). | |
| char * | protocol_blacklist |
| ',' separated list of disallowed protocols. More... | |
| int | max_streams |
| The maximum number of streams. More... | |
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.
Fields can be accessed through AVOptions (av_opt*), the name string used matches the associated command line parameter name and can be found in libavformat/options_table.h. The AVOption/command line parameter names differ in some cases from the C structure field names for historic reasons or brevity.
| AVCodec* AVFormatContext::audio_codec |
Forced audio codec.
This allows forcing a specific decoder, even when there are multiple with the same codec_id. Demuxing: Set by user
| enum AVCodecID AVFormatContext::audio_codec_id |
Forced audio codec_id.
Demuxing: Set by user.
| int AVFormatContext::audio_preload |
Audio preload in microseconds.
Note, not all formats support this and unpredictable things may happen if it is used when not supported.
| const AVClass* AVFormatContext::av_class |
A class for logging and AVOptions.
Set by avformat_alloc_context(). Exports (de)muxer private options if they exist.
| int AVFormatContext::avio_flags |
avio flags, used to force AVIO_FLAG_DIRECT.
| int AVFormatContext::avoid_negative_ts |
Avoid negative timestamps during muxing.
Any value of the AVFMT_AVOID_NEG_TS_* constants. Note, this only works when using av_interleaved_write_frame. (interleave_packet_per_dts is in use)
| int64_t AVFormatContext::bit_rate |
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.
| char* AVFormatContext::codec_whitelist |
',' separated list of allowed decoders.
If NULL then all are allowed
| unsigned int AVFormatContext::correct_ts_overflow |
Correct single timestamp overflows.
| int AVFormatContext::ctx_flags |
Flags signalling stream properties.
A combination of AVFMTCTX_*. Set by libavformat.
| AVCodec* AVFormatContext::data_codec |
Forced data codec.
This allows forcing a specific decoder, even when there are multiple with the same codec_id. Demuxing: Set by user
| enum AVCodecID AVFormatContext::data_codec_id |
Forced Data codec_id.
Demuxing: Set by user.
| uint8_t* AVFormatContext::dump_separator |
dump format separator.
can be ", " or "\n " or anything else
| int64_t AVFormatContext::duration |
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.
Demuxing only, set by libavformat.
| enum AVDurationEstimationMethod AVFormatContext::duration_estimation_method |
The duration field can be estimated through various ways, and this field can be used to know how the duration was estimated.
| int AVFormatContext::error_recognition |
Error recognition; higher values will detect more errors but may misdetect some more or less valid parts as errors.
Demuxing only, set by the caller before avformat_open_input().
| int AVFormatContext::event_flags |
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 AVFormatContext::flags |
Flags modifying the (de)muxer behaviour.
A combination of AVFMT_FLAG_*. Set by the user before avformat_open_input() / avformat_write_header().
| int AVFormatContext::flush_packets |
Flush the I/O context after each packet.
| int AVFormatContext::format_probesize |
number of bytes to read maximally to identify format.
| char* AVFormatContext::format_whitelist |
',' separated list of allowed demuxers.
If NULL then all are allowed
| int AVFormatContext::fps_probe_size |
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().
| struct AVInputFormat* AVFormatContext::iformat |
The input container format.
Demuxing only, set by avformat_open_input().
| AVFormatInternal* AVFormatContext::internal |
An opaque field for libavformat internal usage.
Must not be accessed in any way by callers.
| AVIOInterruptCB AVFormatContext::interrupt_callback |
Custom interrupt callbacks for the I/O layer.
demuxing: set by the user before avformat_open_input(). muxing: 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.
| int(* AVFormatContext::io_open) (struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags, AVDictionary **options) |
A callback for opening new IO streams.
Whenever a muxer or a demuxer needs to open an IO stream (typically from avformat_open_input() for demuxers, but for certain formats can happen at other times as well), it will call this callback to obtain an IO context.
| s | the format context |
| pb | on success, the newly opened IO context should be returned here |
| url | the url to open |
| flags | a combination of AVIO_FLAG_* |
| options | a dictionary of additional options, with the same semantics as in avio_open2() |
| int AVFormatContext::io_repositioned |
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.
| int64_t AVFormatContext::max_analyze_duration |
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.
| int AVFormatContext::max_chunk_duration |
Max chunk time in microseconds.
Note, not all formats support this and unpredictable things may happen if it is used when not supported.
| int AVFormatContext::max_chunk_size |
Max chunk size in bytes Note, not all formats support this and unpredictable things may happen if it is used when not supported.
| unsigned int AVFormatContext::max_index_size |
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.
| int64_t AVFormatContext::max_interleave_delta |
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().
| int AVFormatContext::max_streams |
The maximum number of streams.
| int AVFormatContext::max_ts_probe |
Maximum number of packets to read while waiting for the first timestamp.
Decoding only.
| AVDictionary* AVFormatContext::metadata |
Metadata that applies to the whole file.
Freed by libavformat in avformat_free_context().
| int AVFormatContext::metadata_header_padding |
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.
| unsigned int AVFormatContext::nb_chapters |
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.
| unsigned int AVFormatContext::nb_streams |
Number of elements in AVFormatContext.streams.
Set by avformat_new_stream(), must not be modified by any other code.
| struct AVOutputFormat* AVFormatContext::oformat |
The output container format.
Muxing only, must be set by the caller before avformat_write_header().
| void* AVFormatContext::opaque |
User data.
This is a place for some private data of the user.
| int64_t AVFormatContext::output_ts_offset |
Output timestamp offset, in microseconds.
Muxing: set by user
| AVIOContext* AVFormatContext::pb |
I/O context.
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.
| void* AVFormatContext::priv_data |
Format private data.
This is an AVOptions-enabled struct if and only if iformat/oformat.priv_class is not NULL.
| int AVFormatContext::probe_score |
format probing score.
The maximal score is AVPROBE_SCORE_MAX, its set when the demuxer probes the format.
| int64_t AVFormatContext::probesize |
Maximum size of the data read from input for determining the input container format.
Demuxing only, set by the caller before avformat_open_input().
| char* AVFormatContext::protocol_blacklist |
',' separated list of disallowed protocols.
| char* AVFormatContext::protocol_whitelist |
',' separated list of allowed protocols.
| int AVFormatContext::seek2any |
Force seeking to any (also non key) frames.
| int64_t AVFormatContext::skip_initial_bytes |
Skip initial bytes when opening stream.
| int64_t AVFormatContext::start_time |
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.
Demuxing only, set by libavformat.
| int64_t AVFormatContext::start_time_realtime |
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.
| AVStream** AVFormatContext::streams |
A list of all streams in the file.
New streams are created with avformat_new_stream().
Freed by libavformat in avformat_free_context().
| int AVFormatContext::strict_std_compliance |
Allow non-standard and experimental extension.
| AVCodec* AVFormatContext::subtitle_codec |
Forced subtitle codec.
This allows forcing a specific decoder, even when there are multiple with the same codec_id. Demuxing: Set by user
| enum AVCodecID AVFormatContext::subtitle_codec_id |
Forced subtitle codec_id.
Demuxing: Set by user.
| int AVFormatContext::ts_id |
Transport stream id.
This will be moved into demuxer private options. Thus no API/ABI compatibility
| char* AVFormatContext::url |
input or output URL.
Unlike the old filename field, this field has no length restriction.
Freed by libavformat in avformat_free_context().
| int AVFormatContext::use_wallclock_as_timestamps |
forces the use of wallclock timestamps as pts/dts of packets This has undefined results in the presence of B frames.
| AVCodec* AVFormatContext::video_codec |
Forced video codec.
This allows forcing a specific decoder, even when there are multiple with the same codec_id. Demuxing: Set by user
| enum AVCodecID AVFormatContext::video_codec_id |
Forced video codec_id.
Demuxing: Set by user.
1.8.12