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- \input texinfo @c -*- texinfo -*-
- @documentencoding UTF-8
- @settitle ffmpeg Documentation
- @titlepage
- @center @titlefont{ffmpeg Documentation}
- @end titlepage
- @top
- @contents
- @chapter Synopsis
- ffmpeg [@var{global_options}] @{[@var{input_file_options}] -i @file{input_url}@} ... @{[@var{output_file_options}] @file{output_url}@} ...
- @chapter Description
- @c man begin DESCRIPTION
- @command{ffmpeg} is a universal media converter. It can read a wide variety of
- inputs - including live grabbing/recording devices - filter, and transcode them
- into a plethora of output formats.
- @command{ffmpeg} reads from an arbitrary number of input "files" (which can be regular
- files, pipes, network streams, grabbing devices, etc.), specified by the
- @code{-i} option, and writes to an arbitrary number of output "files", which are
- specified by a plain output url. Anything found on the command line which
- cannot be interpreted as an option is considered to be an output url.
- Each input or output url can, in principle, contain any number of streams of
- different types (video/audio/subtitle/attachment/data). The allowed number and/or
- types of streams may be limited by the container format. Selecting which
- streams from which inputs will go into which output is either done automatically
- or with the @code{-map} option (see the Stream selection chapter).
- To refer to input files in options, you must use their indices (0-based). E.g.
- the first input file is @code{0}, the second is @code{1}, etc. Similarly, streams
- within a file are referred to by their indices. E.g. @code{2:3} refers to the
- fourth stream in the third input file. Also see the Stream specifiers chapter.
- As a general rule, options are applied to the next specified
- file. Therefore, order is important, and you can have the same
- option on the command line multiple times. Each occurrence is
- then applied to the next input or output file.
- Exceptions from this rule are the global options (e.g. verbosity level),
- which should be specified first.
- Do not mix input and output files -- first specify all input files, then all
- output files. Also do not mix options which belong to different files. All
- options apply ONLY to the next input or output file and are reset between files.
- Some simple examples follow.
- @itemize
- @item
- Convert an input media file to a different format, by re-encoding media streams:
- @example
- ffmpeg -i input.avi output.mp4
- @end example
- @item
- Set the video bitrate of the output file to 64 kbit/s:
- @example
- ffmpeg -i input.avi -b:v 64k -bufsize 64k output.mp4
- @end example
- @item
- Force the frame rate of the output file to 24 fps:
- @example
- ffmpeg -i input.avi -r 24 output.mp4
- @end example
- @item
- Force the frame rate of the input file (valid for raw formats only) to 1 fps and
- the frame rate of the output file to 24 fps:
- @example
- ffmpeg -r 1 -i input.m2v -r 24 output.mp4
- @end example
- @end itemize
- The format option may be needed for raw input files.
- @c man end DESCRIPTION
- @chapter Detailed description
- @c man begin DETAILED DESCRIPTION
- The transcoding process in @command{ffmpeg} for each output can be described by
- the following diagram:
- @verbatim
- _______ ______________
- | | | |
- | input | demuxer | encoded data | decoder
- | file | ---------> | packets | -----+
- |_______| |______________| |
- v
- _________
- | |
- | decoded |
- | frames |
- |_________|
- ________ ______________ |
- | | | | |
- | output | <-------- | encoded data | <----+
- | file | muxer | packets | encoder
- |________| |______________|
- @end verbatim
- @command{ffmpeg} calls the libavformat library (containing demuxers) to read
- input files and get packets containing encoded data from them. When there are
- multiple input files, @command{ffmpeg} tries to keep them synchronized by
- tracking lowest timestamp on any active input stream.
- Encoded packets are then passed to the decoder (unless streamcopy is selected
- for the stream, see further for a description). The decoder produces
- uncompressed frames (raw video/PCM audio/...) which can be processed further by
- filtering (see next section). After filtering, the frames are passed to the
- encoder, which encodes them and outputs encoded packets. Finally, those are
- passed to the muxer, which writes the encoded packets to the output file.
- @section Filtering
- Before encoding, @command{ffmpeg} can process raw audio and video frames using
- filters from the libavfilter library. Several chained filters form a filter
- graph. @command{ffmpeg} distinguishes between two types of filtergraphs:
- simple and complex.
- @subsection Simple filtergraphs
- Simple filtergraphs are those that have exactly one input and output, both of
- the same type. In the above diagram they can be represented by simply inserting
- an additional step between decoding and encoding:
- @verbatim
- _________ ______________
- | | | |
- | decoded | | encoded data |
- | frames |\ _ | packets |
- |_________| \ /||______________|
- \ __________ /
- simple _\|| | / encoder
- filtergraph | filtered |/
- | frames |
- |__________|
- @end verbatim
- Simple filtergraphs are configured with the per-stream @option{-filter} option
- (with @option{-vf} and @option{-af} aliases for video and audio respectively).
- A simple filtergraph for video can look for example like this:
- @verbatim
- _______ _____________ _______ ________
- | | | | | | | |
- | input | ---> | deinterlace | ---> | scale | ---> | output |
- |_______| |_____________| |_______| |________|
- @end verbatim
- Note that some filters change frame properties but not frame contents. E.g. the
- @code{fps} filter in the example above changes number of frames, but does not
- touch the frame contents. Another example is the @code{setpts} filter, which
- only sets timestamps and otherwise passes the frames unchanged.
- @subsection Complex filtergraphs
- Complex filtergraphs are those which cannot be described as simply a linear
- processing chain applied to one stream. This is the case, for example, when the graph has
- more than one input and/or output, or when output stream type is different from
- input. They can be represented with the following diagram:
- @verbatim
- _________
- | |
- | input 0 |\ __________
- |_________| \ | |
- \ _________ /| output 0 |
- \ | | / |__________|
- _________ \| complex | /
- | | | |/
- | input 1 |---->| filter |\
- |_________| | | \ __________
- /| graph | \ | |
- / | | \| output 1 |
- _________ / |_________| |__________|
- | | /
- | input 2 |/
- |_________|
- @end verbatim
- Complex filtergraphs are configured with the @option{-filter_complex} option.
- Note that this option is global, since a complex filtergraph, by its nature,
- cannot be unambiguously associated with a single stream or file.
- The @option{-lavfi} option is equivalent to @option{-filter_complex}.
- A trivial example of a complex filtergraph is the @code{overlay} filter, which
- has two video inputs and one video output, containing one video overlaid on top
- of the other. Its audio counterpart is the @code{amix} filter.
- @section Stream copy
- Stream copy is a mode selected by supplying the @code{copy} parameter to the
- @option{-codec} option. It makes @command{ffmpeg} omit the decoding and encoding
- step for the specified stream, so it does only demuxing and muxing. It is useful
- for changing the container format or modifying container-level metadata. The
- diagram above will, in this case, simplify to this:
- @verbatim
- _______ ______________ ________
- | | | | | |
- | input | demuxer | encoded data | muxer | output |
- | file | ---------> | packets | -------> | file |
- |_______| |______________| |________|
- @end verbatim
- Since there is no decoding or encoding, it is very fast and there is no quality
- loss. However, it might not work in some cases because of many factors. Applying
- filters is obviously also impossible, since filters work on uncompressed data.
- @section Loopback decoders
- While decoders are normally associated with demuxer streams, it is also possible
- to create "loopback" decoders that decode the output from some encoder and allow
- it to be fed back to complex filtergraphs. This is done with the @code{-dec}
- directive, which takes as a parameter the index of the output stream that should
- be decoded. Every such directive creates a new loopback decoder, indexed with
- successive integers starting at zero. These indices should then be used to refer
- to loopback decoders in complex filtergraph link labels, as described in the
- documentation for @option{-filter_complex}.
- Decoding AVOptions can be passed to loopback decoders by placing them before
- @code{-dec}, analogously to input/output options.
- E.g. the following example:
- @example
- ffmpeg -i INPUT \
- -map 0:v:0 -c:v libx264 -crf 45 -f null - \
- -threads 3 -dec 0:0 \
- -filter_complex '[0:v][dec:0]hstack[stack]' \
- -map '[stack]' -c:v ffv1 OUTPUT
- @end example
- reads an input video and
- @itemize
- @item
- (line 2) encodes it with @code{libx264} at low quality;
- @item
- (line 3) decodes this encoded stream using 3 threads;
- @item
- (line 4) places decoded video side by side with the original input video;
- @item
- (line 5) combined video is then losslessly encoded and written into
- @file{OUTPUT}.
- @end itemize
- @c man end DETAILED DESCRIPTION
- @chapter Stream selection
- @c man begin STREAM SELECTION
- @command{ffmpeg} provides the @code{-map} option for manual control of stream selection in each
- output file. Users can skip @code{-map} and let ffmpeg perform automatic stream selection as
- described below. The @code{-vn / -an / -sn / -dn} options can be used to skip inclusion of
- video, audio, subtitle and data streams respectively, whether manually mapped or automatically
- selected, except for those streams which are outputs of complex filtergraphs.
- @section Description
- The sub-sections that follow describe the various rules that are involved in stream selection.
- The examples that follow next show how these rules are applied in practice.
- While every effort is made to accurately reflect the behavior of the program, FFmpeg is under
- continuous development and the code may have changed since the time of this writing.
- @subsection Automatic stream selection
- In the absence of any map options for a particular output file, ffmpeg inspects the output
- format to check which type of streams can be included in it, viz. video, audio and/or
- subtitles. For each acceptable stream type, ffmpeg will pick one stream, when available,
- from among all the inputs.
- It will select that stream based upon the following criteria:
- @itemize
- @item
- for video, it is the stream with the highest resolution,
- @item
- for audio, it is the stream with the most channels,
- @item
- for subtitles, it is the first subtitle stream found but there's a caveat.
- The output format's default subtitle encoder can be either text-based or image-based,
- and only a subtitle stream of the same type will be chosen.
- @end itemize
- In the case where several streams of the same type rate equally, the stream with the lowest
- index is chosen.
- Data or attachment streams are not automatically selected and can only be included
- using @code{-map}.
- @subsection Manual stream selection
- When @code{-map} is used, only user-mapped streams are included in that output file,
- with one possible exception for filtergraph outputs described below.
- @subsection Complex filtergraphs
- If there are any complex filtergraph output streams with unlabeled pads, they will be added
- to the first output file. This will lead to a fatal error if the stream type is not supported
- by the output format. In the absence of the map option, the inclusion of these streams leads
- to the automatic stream selection of their types being skipped. If map options are present,
- these filtergraph streams are included in addition to the mapped streams.
- Complex filtergraph output streams with labeled pads must be mapped once and exactly once.
- @subsection Stream handling
- Stream handling is independent of stream selection, with an exception for subtitles described
- below. Stream handling is set via the @code{-codec} option addressed to streams within a
- specific @emph{output} file. In particular, codec options are applied by ffmpeg after the
- stream selection process and thus do not influence the latter. If no @code{-codec} option is
- specified for a stream type, ffmpeg will select the default encoder registered by the output
- file muxer.
- An exception exists for subtitles. If a subtitle encoder is specified for an output file, the
- first subtitle stream found of any type, text or image, will be included. ffmpeg does not validate
- if the specified encoder can convert the selected stream or if the converted stream is acceptable
- within the output format. This applies generally as well: when the user sets an encoder manually,
- the stream selection process cannot check if the encoded stream can be muxed into the output file.
- If it cannot, ffmpeg will abort and @emph{all} output files will fail to be processed.
- @section Examples
- The following examples illustrate the behavior, quirks and limitations of ffmpeg's stream
- selection methods.
- They assume the following three input files.
- @verbatim
- input file 'A.avi'
- stream 0: video 640x360
- stream 1: audio 2 channels
- input file 'B.mp4'
- stream 0: video 1920x1080
- stream 1: audio 2 channels
- stream 2: subtitles (text)
- stream 3: audio 5.1 channels
- stream 4: subtitles (text)
- input file 'C.mkv'
- stream 0: video 1280x720
- stream 1: audio 2 channels
- stream 2: subtitles (image)
- @end verbatim
- @subsubheading Example: automatic stream selection
- @example
- ffmpeg -i A.avi -i B.mp4 out1.mkv out2.wav -map 1:a -c:a copy out3.mov
- @end example
- There are three output files specified, and for the first two, no @code{-map} options
- are set, so ffmpeg will select streams for these two files automatically.
- @file{out1.mkv} is a Matroska container file and accepts video, audio and subtitle streams,
- so ffmpeg will try to select one of each type.@*
- For video, it will select @code{stream 0} from @file{B.mp4}, which has the highest
- resolution among all the input video streams.@*
- For audio, it will select @code{stream 3} from @file{B.mp4}, since it has the greatest
- number of channels.@*
- For subtitles, it will select @code{stream 2} from @file{B.mp4}, which is the first subtitle
- stream from among @file{A.avi} and @file{B.mp4}.
- @file{out2.wav} accepts only audio streams, so only @code{stream 3} from @file{B.mp4} is
- selected.
- For @file{out3.mov}, since a @code{-map} option is set, no automatic stream selection will
- occur. The @code{-map 1:a} option will select all audio streams from the second input
- @file{B.mp4}. No other streams will be included in this output file.
- For the first two outputs, all included streams will be transcoded. The encoders chosen will
- be the default ones registered by each output format, which may not match the codec of the
- selected input streams.
- For the third output, codec option for audio streams has been set
- to @code{copy}, so no decoding-filtering-encoding operations will occur, or @emph{can} occur.
- Packets of selected streams shall be conveyed from the input file and muxed within the output
- file.
- @subsubheading Example: automatic subtitles selection
- @example
- ffmpeg -i C.mkv out1.mkv -c:s dvdsub -an out2.mkv
- @end example
- Although @file{out1.mkv} is a Matroska container file which accepts subtitle streams, only a
- video and audio stream shall be selected. The subtitle stream of @file{C.mkv} is image-based
- and the default subtitle encoder of the Matroska muxer is text-based, so a transcode operation
- for the subtitles is expected to fail and hence the stream isn't selected. However, in
- @file{out2.mkv}, a subtitle encoder is specified in the command and so, the subtitle stream is
- selected, in addition to the video stream. The presence of @code{-an} disables audio stream
- selection for @file{out2.mkv}.
- @subsubheading Example: unlabeled filtergraph outputs
- @example
- ffmpeg -i A.avi -i C.mkv -i B.mp4 -filter_complex "overlay" out1.mp4 out2.srt
- @end example
- A filtergraph is setup here using the @code{-filter_complex} option and consists of a single
- video filter. The @code{overlay} filter requires exactly two video inputs, but none are
- specified, so the first two available video streams are used, those of @file{A.avi} and
- @file{C.mkv}. The output pad of the filter has no label and so is sent to the first output file
- @file{out1.mp4}. Due to this, automatic selection of the video stream is skipped, which would
- have selected the stream in @file{B.mp4}. The audio stream with most channels viz. @code{stream 3}
- in @file{B.mp4}, is chosen automatically. No subtitle stream is chosen however, since the MP4
- format has no default subtitle encoder registered, and the user hasn't specified a subtitle encoder.
- The 2nd output file, @file{out2.srt}, only accepts text-based subtitle streams. So, even though
- the first subtitle stream available belongs to @file{C.mkv}, it is image-based and hence skipped.
- The selected stream, @code{stream 2} in @file{B.mp4}, is the first text-based subtitle stream.
- @subsubheading Example: labeled filtergraph outputs
- @example
- ffmpeg -i A.avi -i B.mp4 -i C.mkv -filter_complex "[1:v]hue=s=0[outv];overlay;aresample" \
- -map '[outv]' -an out1.mp4 \
- out2.mkv \
- -map '[outv]' -map 1:a:0 out3.mkv
- @end example
- The above command will fail, as the output pad labelled @code{[outv]} has been mapped twice.
- None of the output files shall be processed.
- @example
- ffmpeg -i A.avi -i B.mp4 -i C.mkv -filter_complex "[1:v]hue=s=0[outv];overlay;aresample" \
- -an out1.mp4 \
- out2.mkv \
- -map 1:a:0 out3.mkv
- @end example
- This command above will also fail as the hue filter output has a label, @code{[outv]},
- and hasn't been mapped anywhere.
- The command should be modified as follows,
- @example
- ffmpeg -i A.avi -i B.mp4 -i C.mkv -filter_complex "[1:v]hue=s=0,split=2[outv1][outv2];overlay;aresample" \
- -map '[outv1]' -an out1.mp4 \
- out2.mkv \
- -map '[outv2]' -map 1:a:0 out3.mkv
- @end example
- The video stream from @file{B.mp4} is sent to the hue filter, whose output is cloned once using
- the split filter, and both outputs labelled. Then a copy each is mapped to the first and third
- output files.
- The overlay filter, requiring two video inputs, uses the first two unused video streams. Those
- are the streams from @file{A.avi} and @file{C.mkv}. The overlay output isn't labelled, so it is
- sent to the first output file @file{out1.mp4}, regardless of the presence of the @code{-map} option.
- The aresample filter is sent the first unused audio stream, that of @file{A.avi}. Since this filter
- output is also unlabelled, it too is mapped to the first output file. The presence of @code{-an}
- only suppresses automatic or manual stream selection of audio streams, not outputs sent from
- filtergraphs. Both these mapped streams shall be ordered before the mapped stream in @file{out1.mp4}.
- The video, audio and subtitle streams mapped to @code{out2.mkv} are entirely determined by
- automatic stream selection.
- @file{out3.mkv} consists of the cloned video output from the hue filter and the first audio
- stream from @file{B.mp4}.
- @*
- @c man end STREAM SELECTION
- @chapter Options
- @c man begin OPTIONS
- @include fftools-common-opts.texi
- @section Main options
- @table @option
- @item -f @var{fmt} (@emph{input/output})
- Force input or output file format. The format is normally auto detected for input
- files and guessed from the file extension for output files, so this option is not
- needed in most cases.
- @item -i @var{url} (@emph{input})
- input file url
- @item -y (@emph{global})
- Overwrite output files without asking.
- @item -n (@emph{global})
- Do not overwrite output files, and exit immediately if a specified
- output file already exists.
- @item -stream_loop @var{number} (@emph{input})
- Set number of times input stream shall be looped. Loop 0 means no loop,
- loop -1 means infinite loop.
- @item -recast_media (@emph{global})
- Allow forcing a decoder of a different media type than the one
- detected or designated by the demuxer. Useful for decoding media
- data muxed as data streams.
- @item -c[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
- @itemx -codec[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
- Select an encoder (when used before an output file) or a decoder (when used
- before an input file) for one or more streams. @var{codec} is the name of a
- decoder/encoder or a special value @code{copy} (output only) to indicate that
- the stream is not to be re-encoded.
- For example
- @example
- ffmpeg -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
- @end example
- encodes all video streams with libx264 and copies all audio streams.
- For each stream, the last matching @code{c} option is applied, so
- @example
- ffmpeg -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
- @end example
- will copy all the streams except the second video, which will be encoded with
- libx264, and the 138th audio, which will be encoded with libvorbis.
- @item -t @var{duration} (@emph{input/output})
- When used as an input option (before @code{-i}), limit the @var{duration} of
- data read from the input file.
- When used as an output option (before an output url), stop writing the
- output after its duration reaches @var{duration}.
- @var{duration} must be a time duration specification,
- see @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
- -to and -t are mutually exclusive and -t has priority.
- @item -to @var{position} (@emph{input/output})
- Stop writing the output or reading the input at @var{position}.
- @var{position} must be a time duration specification,
- see @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
- -to and -t are mutually exclusive and -t has priority.
- @item -fs @var{limit_size} (@emph{output})
- Set the file size limit, expressed in bytes. No further chunk of bytes is written
- after the limit is exceeded. The size of the output file is slightly more than the
- requested file size.
- @item -ss @var{position} (@emph{input/output})
- When used as an input option (before @code{-i}), seeks in this input file to
- @var{position}. Note that in most formats it is not possible to seek exactly,
- so @command{ffmpeg} will seek to the closest seek point before @var{position}.
- When transcoding and @option{-accurate_seek} is enabled (the default), this
- extra segment between the seek point and @var{position} will be decoded and
- discarded. When doing stream copy or when @option{-noaccurate_seek} is used, it
- will be preserved.
- When used as an output option (before an output url), decodes but discards
- input until the timestamps reach @var{position}.
- @var{position} must be a time duration specification,
- see @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
- @item -sseof @var{position} (@emph{input})
- Like the @code{-ss} option but relative to the "end of file". That is negative
- values are earlier in the file, 0 is at EOF.
- @item -isync @var{input_index} (@emph{input})
- Assign an input as a sync source.
- This will take the difference between the start times of the target and reference inputs and
- offset the timestamps of the target file by that difference. The source timestamps of the two
- inputs should derive from the same clock source for expected results. If @code{copyts} is set
- then @code{start_at_zero} must also be set. If either of the inputs has no starting timestamp
- then no sync adjustment is made.
- Acceptable values are those that refer to a valid ffmpeg input index. If the sync reference is
- the target index itself or @var{-1}, then no adjustment is made to target timestamps. A sync
- reference may not itself be synced to any other input.
- Default value is @var{-1}.
- @item -itsoffset @var{offset} (@emph{input})
- Set the input time offset.
- @var{offset} must be a time duration specification,
- see @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
- The offset is added to the timestamps of the input files. Specifying
- a positive offset means that the corresponding streams are delayed by
- the time duration specified in @var{offset}.
- @item -itsscale @var{scale} (@emph{input,per-stream})
- Rescale input timestamps. @var{scale} should be a floating point number.
- @item -timestamp @var{date} (@emph{output})
- Set the recording timestamp in the container.
- @var{date} must be a date specification,
- see @ref{date syntax,,the Date section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
- @item -metadata[:metadata_specifier] @var{key}=@var{value} (@emph{output,per-metadata})
- Set a metadata key/value pair.
- An optional @var{metadata_specifier} may be given to set metadata
- on streams, chapters or programs. See @code{-map_metadata}
- documentation for details.
- This option overrides metadata set with @code{-map_metadata}. It is
- also possible to delete metadata by using an empty value.
- For example, for setting the title in the output file:
- @example
- ffmpeg -i in.avi -metadata title="my title" out.flv
- @end example
- To set the language of the first audio stream:
- @example
- ffmpeg -i INPUT -metadata:s:a:0 language=eng OUTPUT
- @end example
- @item -disposition[:stream_specifier] @var{value} (@emph{output,per-stream})
- Sets the disposition for a stream.
- By default, the disposition is copied from the input stream, unless the output
- stream this option applies to is fed by a complex filtergraph - in that case the
- disposition is unset by default.
- @var{value} is a sequence of items separated by '+' or '-'. The first item may
- also be prefixed with '+' or '-', in which case this option modifies the default
- value. Otherwise (the first item is not prefixed) this options overrides the
- default value. A '+' prefix adds the given disposition, '-' removes it. It is
- also possible to clear the disposition by setting it to 0.
- If no @code{-disposition} options were specified for an output file, ffmpeg will
- automatically set the 'default' disposition on the first stream of each type,
- when there are multiple streams of this type in the output file and no stream of
- that type is already marked as default.
- The @code{-dispositions} option lists the known dispositions.
- For example, to make the second audio stream the default stream:
- @example
- ffmpeg -i in.mkv -c copy -disposition:a:1 default out.mkv
- @end example
- To make the second subtitle stream the default stream and remove the default
- disposition from the first subtitle stream:
- @example
- ffmpeg -i in.mkv -c copy -disposition:s:0 0 -disposition:s:1 default out.mkv
- @end example
- To add an embedded cover/thumbnail:
- @example
- ffmpeg -i in.mp4 -i IMAGE -map 0 -map 1 -c copy -c:v:1 png -disposition:v:1 attached_pic out.mp4
- @end example
- Not all muxers support embedded thumbnails, and those who do, only support a few formats, like JPEG or PNG.
- @item -program [title=@var{title}:][program_num=@var{program_num}:]st=@var{stream}[:st=@var{stream}...] (@emph{output})
- Creates a program with the specified @var{title}, @var{program_num} and adds the specified
- @var{stream}(s) to it.
- @item -stream_group [map=@var{input_file_id}=@var{stream_group}][type=@var{type}:]st=@var{stream}[:st=@var{stream}][:stg=@var{stream_group}][:id=@var{stream_group_id}...] (@emph{output})
- Creates a stream group of the specified @var{type} and @var{stream_group_id}, or by
- @var{map}ping an input group, adding the specified @var{stream}(s) and/or previously
- defined @var{stream_group}(s) to it.
- @var{type} can be one of the following:
- @table @option
- @item iamf_audio_element
- Groups @var{stream}s that belong to the same IAMF Audio Element
- For this group @var{type}, the following options are available
- @table @option
- @item audio_element_type
- The Audio Element type. The following values are supported:
- @table @option
- @item channel
- Scalable channel audio representation
- @item scene
- Ambisonics representation
- @end table
- @item demixing
- Demixing information used to reconstruct a scalable channel audio representation.
- This option must be separated from the rest with a ',', and takes the following
- key=value options
- @table @option
- @item parameter_id
- An identifier parameters blocks in frames may refer to
- @item dmixp_mode
- A pre-defined combination of demixing parameters
- @end table
- @item recon_gain
- Recon gain information used to reconstruct a scalable channel audio representation.
- This option must be separated from the rest with a ',', and takes the following
- key=value options
- @table @option
- @item parameter_id
- An identifier parameters blocks in frames may refer to
- @end table
- @item layer
- A layer defining a Channel Layout in the Audio Element.
- This option must be separated from the rest with a ','. Several ',' separated entries
- can be defined, and at least one must be set.
- It takes the following ":"-separated key=value options
- @table @option
- @item ch_layout
- The layer's channel layout
- @item flags
- The following flags are available:
- @table @option
- @item recon_gain
- Wether to signal if recon_gain is present as metadata in parameter blocks within frames
- @end table
- @item output_gain
- @item output_gain_flags
- Which channels output_gain applies to. The following flags are available:
- @table @option
- @item FL
- @item FR
- @item BL
- @item BR
- @item TFL
- @item TFR
- @end table
- @item ambisonics_mode
- The ambisonics mode. This has no effect if audio_element_type is set to channel.
- The following values are supported:
- @table @option
- @item mono
- Each ambisonics channel is coded as an individual mono stream in the group
- @end table
- @end table
- @item default_w
- Default weight value
- @end table
- @item iamf_mix_presentation
- Groups @var{stream}s that belong to all IAMF Audio Element the same
- IAMF Mix Presentation references
- For this group @var{type}, the following options are available
- @table @option
- @item submix
- A sub-mix within the Mix Presentation.
- This option must be separated from the rest with a ','. Several ',' separated entries
- can be defined, and at least one must be set.
- It takes the following ":"-separated key=value options
- @table @option
- @item parameter_id
- An identifier parameters blocks in frames may refer to, for post-processing the mixed
- audio signal to generate the audio signal for playback
- @item parameter_rate
- The sample rate duration fields in parameters blocks in frames that refer to this
- @var{parameter_id} are expressed as
- @item default_mix_gain
- Default mix gain value to apply when there are no parameter blocks sharing the same
- @var{parameter_id} for a given frame
- @item element
- References an Audio Element used in this Mix Presentation to generate the final output
- audio signal for playback.
- This option must be separated from the rest with a '|'. Several '|' separated entries
- can be defined, and at least one must be set.
- It takes the following ":"-separated key=value options:
- @table @option
- @item stg
- The @var{stream_group_id} for an Audio Element which this sub-mix refers to
- @item parameter_id
- An identifier parameters blocks in frames may refer to, for applying any processing to
- the referenced and rendered Audio Element before being summed with other processed Audio
- Elements
- @item parameter_rate
- The sample rate duration fields in parameters blocks in frames that refer to this
- @var{parameter_id} are expressed as
- @item default_mix_gain
- Default mix gain value to apply when there are no parameter blocks sharing the same
- @var{parameter_id} for a given frame
- @item annotations
- A key=value string describing the sub-mix element where "key" is a string conforming to
- BCP-47 that specifies the language for the "value" string. "key" must be the same as the
- one in the mix's @var{annotations}
- @item headphones_rendering_mode
- Indicates whether the input channel-based Audio Element is rendered to stereo loudspeakers
- or spatialized with a binaural renderer when played back on headphones.
- This has no effect if the referenced Audio Element's @var{audio_element_type} is set to
- channel.
- The following values are supported:
- @table @option
- @item stereo
- @item binaural
- @end table
- @end table
- @item layout
- Specifies the layouts for this sub-mix on which the loudness information was measured.
- This option must be separated from the rest with a '|'. Several '|' separated entries
- can be defined, and at least one must be set.
- It takes the following ":"-separated key=value options:
- @table @option
- @item layout_type
- @table @option
- @item loudspeakers
- The layout follows the loudspeaker sound system convention of ITU-2051-3.
- @item binaural
- The layout is binaural.
- @end table
- @item sound_system
- Channel layout matching one of Sound Systems A to J of ITU-2051-3, plus 7.1.2 and 3.1.2
- This has no effect if @var{layout_type} is set to binaural.
- @item integrated_loudness
- The program integrated loudness information, as defined in ITU-1770-4.
- @item digital_peak
- The digital (sampled) peak value of the audio signal, as defined in ITU-1770-4.
- @item true_peak
- The true peak of the audio signal, as defined in ITU-1770-4.
- @item dialog_anchored_loudness
- The Dialogue loudness information, as defined in ITU-1770-4.
- @item album_anchored_loudness
- The Album loudness information, as defined in ITU-1770-4.
- @end table
- @end table
- @item annotations
- A key=value string string describing the mix where "key" is a string conforming to BCP-47
- that specifies the language for the "value" string. "key" must be the same as the ones in
- all sub-mix element's @var{annotations}s
- @end table
- @end table
- E.g. to create an scalable 5.1 IAMF file from several WAV input files
- @example
- ffmpeg -i front.wav -i back.wav -i center.wav -i lfe.wav
- -map 0:0 -map 1:0 -map 2:0 -map 3:0 -c:a opus
- -stream_group type=iamf_audio_element:id=1:st=0:st=1:st=2:st=3,
- demixing=parameter_id=998,
- recon_gain=parameter_id=101,
- layer=ch_layout=stereo,
- layer=ch_layout=5.1,
- -stream_group type=iamf_mix_presentation:id=2:stg=0:annotations=en-us=Mix_Presentation,
- submix=parameter_id=100:parameter_rate=48000|element=stg=0:parameter_id=100:annotations=en-us=Scalable_Submix|layout=sound_system=stereo|layout=sound_system=5.1
- -streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 output.iamf
- @end example
- To copy the two stream groups (Audio Element and Mix Presentation) from an input IAMF file with four
- streams into an mp4 output
- @example
- ffmpeg -i input.iamf -c:a copy -stream_group map=0=0:st=0:st=1:st=2:st=3 -stream_group map=0=1:stg=0
- -streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 output.mp4
- @end example
- @item -target @var{type} (@emph{output})
- Specify target file type (@code{vcd}, @code{svcd}, @code{dvd}, @code{dv},
- @code{dv50}). @var{type} may be prefixed with @code{pal-}, @code{ntsc-} or
- @code{film-} to use the corresponding standard. All the format options
- (bitrate, codecs, buffer sizes) are then set automatically. You can just type:
- @example
- ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
- @end example
- Nevertheless you can specify additional options as long as you know
- they do not conflict with the standard, as in:
- @example
- ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
- @end example
- The parameters set for each target are as follows.
- @strong{VCD}
- @example
- @var{pal}:
- -f vcd -muxrate 1411200 -muxpreload 0.44 -packetsize 2324
- -s 352x288 -r 25
- -codec:v mpeg1video -g 15 -b:v 1150k -maxrate:v 1150k -minrate:v 1150k -bufsize:v 327680
- -ar 44100 -ac 2
- -codec:a mp2 -b:a 224k
- @var{ntsc}:
- -f vcd -muxrate 1411200 -muxpreload 0.44 -packetsize 2324
- -s 352x240 -r 30000/1001
- -codec:v mpeg1video -g 18 -b:v 1150k -maxrate:v 1150k -minrate:v 1150k -bufsize:v 327680
- -ar 44100 -ac 2
- -codec:a mp2 -b:a 224k
- @var{film}:
- -f vcd -muxrate 1411200 -muxpreload 0.44 -packetsize 2324
- -s 352x240 -r 24000/1001
- -codec:v mpeg1video -g 18 -b:v 1150k -maxrate:v 1150k -minrate:v 1150k -bufsize:v 327680
- -ar 44100 -ac 2
- -codec:a mp2 -b:a 224k
- @end example
- @strong{SVCD}
- @example
- @var{pal}:
- -f svcd -packetsize 2324
- -s 480x576 -pix_fmt yuv420p -r 25
- -codec:v mpeg2video -g 15 -b:v 2040k -maxrate:v 2516k -minrate:v 0 -bufsize:v 1835008 -scan_offset 1
- -ar 44100
- -codec:a mp2 -b:a 224k
- @var{ntsc}:
- -f svcd -packetsize 2324
- -s 480x480 -pix_fmt yuv420p -r 30000/1001
- -codec:v mpeg2video -g 18 -b:v 2040k -maxrate:v 2516k -minrate:v 0 -bufsize:v 1835008 -scan_offset 1
- -ar 44100
- -codec:a mp2 -b:a 224k
- @var{film}:
- -f svcd -packetsize 2324
- -s 480x480 -pix_fmt yuv420p -r 24000/1001
- -codec:v mpeg2video -g 18 -b:v 2040k -maxrate:v 2516k -minrate:v 0 -bufsize:v 1835008 -scan_offset 1
- -ar 44100
- -codec:a mp2 -b:a 224k
- @end example
- @strong{DVD}
- @example
- @var{pal}:
- -f dvd -muxrate 10080k -packetsize 2048
- -s 720x576 -pix_fmt yuv420p -r 25
- -codec:v mpeg2video -g 15 -b:v 6000k -maxrate:v 9000k -minrate:v 0 -bufsize:v 1835008
- -ar 48000
- -codec:a ac3 -b:a 448k
- @var{ntsc}:
- -f dvd -muxrate 10080k -packetsize 2048
- -s 720x480 -pix_fmt yuv420p -r 30000/1001
- -codec:v mpeg2video -g 18 -b:v 6000k -maxrate:v 9000k -minrate:v 0 -bufsize:v 1835008
- -ar 48000
- -codec:a ac3 -b:a 448k
- @var{film}:
- -f dvd -muxrate 10080k -packetsize 2048
- -s 720x480 -pix_fmt yuv420p -r 24000/1001
- -codec:v mpeg2video -g 18 -b:v 6000k -maxrate:v 9000k -minrate:v 0 -bufsize:v 1835008
- -ar 48000
- -codec:a ac3 -b:a 448k
- @end example
- @strong{DV}
- @example
- @var{pal}:
- -f dv
- -s 720x576 -pix_fmt yuv420p -r 25
- -ar 48000 -ac 2
- @var{ntsc}:
- -f dv
- -s 720x480 -pix_fmt yuv411p -r 30000/1001
- -ar 48000 -ac 2
- @var{film}:
- -f dv
- -s 720x480 -pix_fmt yuv411p -r 24000/1001
- -ar 48000 -ac 2
- @end example
- The @code{dv50} target is identical to the @code{dv} target except that the pixel format set is @code{yuv422p} for all three standards.
- Any user-set value for a parameter above will override the target preset value. In that case, the output may
- not comply with the target standard.
- @item -dn (@emph{input/output})
- As an input option, blocks all data streams of a file from being filtered or
- being automatically selected or mapped for any output. See @code{-discard}
- option to disable streams individually.
- As an output option, disables data recording i.e. automatic selection or
- mapping of any data stream. For full manual control see the @code{-map}
- option.
- @item -dframes @var{number} (@emph{output})
- Set the number of data frames to output. This is an obsolete alias for
- @code{-frames:d}, which you should use instead.
- @item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream})
- Stop writing to the stream after @var{framecount} frames.
- @item -q[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
- @itemx -qscale[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
- Use fixed quality scale (VBR). The meaning of @var{q}/@var{qscale} is
- codec-dependent.
- If @var{qscale} is used without a @var{stream_specifier} then it applies only
- to the video stream, this is to maintain compatibility with previous behavior
- and as specifying the same codec specific value to 2 different codecs that is
- audio and video generally is not what is intended when no stream_specifier is
- used.
- @anchor{filter_option}
- @item -filter[:@var{stream_specifier}] @var{filtergraph} (@emph{output,per-stream})
- Create the filtergraph specified by @var{filtergraph} and use it to
- filter the stream.
- @var{filtergraph} is a description of the filtergraph to apply to
- the stream, and must have a single input and a single output of the
- same type of the stream. In the filtergraph, the input is associated
- to the label @code{in}, and the output to the label @code{out}. See
- the ffmpeg-filters manual for more information about the filtergraph
- syntax.
- See the @ref{filter_complex_option,,-filter_complex option} if you
- want to create filtergraphs with multiple inputs and/or outputs.
- @item -reinit_filter[:@var{stream_specifier}] @var{integer} (@emph{input,per-stream})
- This boolean option determines if the filtergraph(s) to which this stream is fed gets
- reinitialized when input frame parameters change mid-stream. This option is enabled by
- default as most video and all audio filters cannot handle deviation in input frame properties.
- Upon reinitialization, existing filter state is lost, like e.g. the frame count @code{n}
- reference available in some filters. Any frames buffered at time of reinitialization are lost.
- The properties where a change triggers reinitialization are,
- for video, frame resolution or pixel format;
- for audio, sample format, sample rate, channel count or channel layout.
- @item -filter_threads @var{nb_threads} (@emph{global})
- Defines how many threads are used to process a filter pipeline. Each pipeline
- will produce a thread pool with this many threads available for parallel processing.
- The default is the number of available CPUs.
- @item -pre[:@var{stream_specifier}] @var{preset_name} (@emph{output,per-stream})
- Specify the preset for matching stream(s).
- @item -stats (@emph{global})
- Print encoding progress/statistics. It is on by default, to explicitly
- disable it you need to specify @code{-nostats}.
- @item -stats_period @var{time} (@emph{global})
- Set period at which encoding progress/statistics are updated. Default is 0.5 seconds.
- @item -progress @var{url} (@emph{global})
- Send program-friendly progress information to @var{url}.
- Progress information is written periodically and at the end of
- the encoding process. It is made of "@var{key}=@var{value}" lines. @var{key}
- consists of only alphanumeric characters. The last key of a sequence of
- progress information is always "progress".
- The update period is set using @code{-stats_period}.
- @anchor{stdin option}
- @item -stdin
- Enable interaction on standard input. On by default unless standard input is
- used as an input. To explicitly disable interaction you need to specify
- @code{-nostdin}.
- Disabling interaction on standard input is useful, for example, if
- ffmpeg is in the background process group. Roughly the same result can
- be achieved with @code{ffmpeg ... < /dev/null} but it requires a
- shell.
- @item -debug_ts (@emph{global})
- Print timestamp/latency information. It is off by default. This option is
- mostly useful for testing and debugging purposes, and the output
- format may change from one version to another, so it should not be
- employed by portable scripts.
- See also the option @code{-fdebug ts}.
- @item -attach @var{filename} (@emph{output})
- Add an attachment to the output file. This is supported by a few formats
- like Matroska for e.g. fonts used in rendering subtitles. Attachments
- are implemented as a specific type of stream, so this option will add
- a new stream to the file. It is then possible to use per-stream options
- on this stream in the usual way. Attachment streams created with this
- option will be created after all the other streams (i.e. those created
- with @code{-map} or automatic mappings).
- Note that for Matroska you also have to set the mimetype metadata tag:
- @example
- ffmpeg -i INPUT -attach DejaVuSans.ttf -metadata:s:2 mimetype=application/x-truetype-font out.mkv
- @end example
- (assuming that the attachment stream will be third in the output file).
- @item -dump_attachment[:@var{stream_specifier}] @var{filename} (@emph{input,per-stream})
- Extract the matching attachment stream into a file named @var{filename}. If
- @var{filename} is empty, then the value of the @code{filename} metadata tag
- will be used.
- E.g. to extract the first attachment to a file named 'out.ttf':
- @example
- ffmpeg -dump_attachment:t:0 out.ttf -i INPUT
- @end example
- To extract all attachments to files determined by the @code{filename} tag:
- @example
- ffmpeg -dump_attachment:t "" -i INPUT
- @end example
- Technical note -- attachments are implemented as codec extradata, so this
- option can actually be used to extract extradata from any stream, not just
- attachments.
- @end table
- @section Video Options
- @table @option
- @item -vframes @var{number} (@emph{output})
- Set the number of video frames to output. This is an obsolete alias for
- @code{-frames:v}, which you should use instead.
- @item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream})
- Set frame rate (Hz value, fraction or abbreviation).
- As an input option, ignore any timestamps stored in the file and instead
- generate timestamps assuming constant frame rate @var{fps}.
- This is not the same as the @option{-framerate} option used for some input formats
- like image2 or v4l2 (it used to be the same in older versions of FFmpeg).
- If in doubt use @option{-framerate} instead of the input option @option{-r}.
- As an output option:
- @table @option
- @item video encoding
- Duplicate or drop frames right before encoding them to achieve constant output
- frame rate @var{fps}.
- @item video streamcopy
- Indicate to the muxer that @var{fps} is the stream frame rate. No data is
- dropped or duplicated in this case. This may produce invalid files if @var{fps}
- does not match the actual stream frame rate as determined by packet timestamps.
- See also the @code{setts} bitstream filter.
- @end table
- @item -fpsmax[:@var{stream_specifier}] @var{fps} (@emph{output,per-stream})
- Set maximum frame rate (Hz value, fraction or abbreviation).
- Clamps output frame rate when output framerate is auto-set and is higher than this value.
- Useful in batch processing or when input framerate is wrongly detected as very high.
- It cannot be set together with @code{-r}. It is ignored during streamcopy.
- @item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream})
- Set frame size.
- As an input option, this is a shortcut for the @option{video_size} private
- option, recognized by some demuxers for which the frame size is either not
- stored in the file or is configurable -- e.g. raw video or video grabbers.
- As an output option, this inserts the @code{scale} video filter to the
- @emph{end} of the corresponding filtergraph. Please use the @code{scale} filter
- directly to insert it at the beginning or some other place.
- The format is @samp{wxh} (default - same as source).
- @item -aspect[:@var{stream_specifier}] @var{aspect} (@emph{output,per-stream})
- Set the video display aspect ratio specified by @var{aspect}.
- @var{aspect} can be a floating point number string, or a string of the
- form @var{num}:@var{den}, where @var{num} and @var{den} are the
- numerator and denominator of the aspect ratio. For example "4:3",
- "16:9", "1.3333", and "1.7777" are valid argument values.
- If used together with @option{-vcodec copy}, it will affect the aspect ratio
- stored at container level, but not the aspect ratio stored in encoded
- frames, if it exists.
- @item -display_rotation[:@var{stream_specifier}] @var{rotation} (@emph{input,per-stream})
- Set video rotation metadata.
- @var{rotation} is a decimal number specifying the amount in degree by
- which the video should be rotated counter-clockwise before being
- displayed.
- This option overrides the rotation/display transform metadata stored in
- the file, if any. When the video is being transcoded (rather than
- copied) and @code{-autorotate} is enabled, the video will be rotated at
- the filtering stage. Otherwise, the metadata will be written into the
- output file if the muxer supports it.
- If the @code{-display_hflip} and/or @code{-display_vflip} options are
- given, they are applied after the rotation specified by this option.
- @item -display_hflip[:@var{stream_specifier}] (@emph{input,per-stream})
- Set whether on display the image should be horizontally flipped.
- See the @code{-display_rotation} option for more details.
- @item -display_vflip[:@var{stream_specifier}] (@emph{input,per-stream})
- Set whether on display the image should be vertically flipped.
- See the @code{-display_rotation} option for more details.
- @item -vn (@emph{input/output})
- As an input option, blocks all video streams of a file from being filtered or
- being automatically selected or mapped for any output. See @code{-discard}
- option to disable streams individually.
- As an output option, disables video recording i.e. automatic selection or
- mapping of any video stream. For full manual control see the @code{-map}
- option.
- @item -vcodec @var{codec} (@emph{output})
- Set the video codec. This is an alias for @code{-codec:v}.
- @item -pass[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
- Select the pass number (1 or 2). It is used to do two-pass
- video encoding. The statistics of the video are recorded in the first
- pass into a log file (see also the option -passlogfile),
- and in the second pass that log file is used to generate the video
- at the exact requested bitrate.
- On pass 1, you may just deactivate audio and set output to null,
- examples for Windows and Unix:
- @example
- ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
- ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
- @end example
- @item -passlogfile[:@var{stream_specifier}] @var{prefix} (@emph{output,per-stream})
- Set two-pass log file name prefix to @var{prefix}, the default file name
- prefix is ``ffmpeg2pass''. The complete file name will be
- @file{PREFIX-N.log}, where N is a number specific to the output
- stream
- @item -vf @var{filtergraph} (@emph{output})
- Create the filtergraph specified by @var{filtergraph} and use it to
- filter the stream.
- This is an alias for @code{-filter:v}, see the @ref{filter_option,,-filter option}.
- @item -autorotate
- Automatically rotate the video according to file metadata. Enabled by
- default, use @option{-noautorotate} to disable it.
- @item -autoscale
- Automatically scale the video according to the resolution of first frame.
- Enabled by default, use @option{-noautoscale} to disable it. When autoscale is
- disabled, all output frames of filter graph might not be in the same resolution
- and may be inadequate for some encoder/muxer. Therefore, it is not recommended
- to disable it unless you really know what you are doing.
- Disable autoscale at your own risk.
- @end table
- @section Advanced Video options
- @table @option
- @item -pix_fmt[:@var{stream_specifier}] @var{format} (@emph{input/output,per-stream})
- Set pixel format. Use @code{-pix_fmts} to show all the supported
- pixel formats.
- If the selected pixel format can not be selected, ffmpeg will print a
- warning and select the best pixel format supported by the encoder.
- If @var{pix_fmt} is prefixed by a @code{+}, ffmpeg will exit with an error
- if the requested pixel format can not be selected, and automatic conversions
- inside filtergraphs are disabled.
- If @var{pix_fmt} is a single @code{+}, ffmpeg selects the same pixel format
- as the input (or graph output) and automatic conversions are disabled.
- @item -sws_flags @var{flags} (@emph{input/output})
- Set default flags for the libswscale library. These flags are used by
- automatically inserted @code{scale} filters and those within simple
- filtergraphs, if not overridden within the filtergraph definition.
- See the @ref{scaler_options,,ffmpeg-scaler manual,ffmpeg-scaler} for a list
- of scaler options.
- @item -rc_override[:@var{stream_specifier}] @var{override} (@emph{output,per-stream})
- Rate control override for specific intervals, formatted as "int,int,int"
- list separated with slashes. Two first values are the beginning and
- end frame numbers, last one is quantizer to use if positive, or quality
- factor if negative.
- @item -vstats
- Dump video coding statistics to @file{vstats_HHMMSS.log}. See the
- @ref{vstats_file_format,,vstats file format} section for the format description.
- @item -vstats_file @var{file}
- Dump video coding statistics to @var{file}. See the
- @ref{vstats_file_format,,vstats file format} section for the format description.
- @item -vstats_version @var{file}
- Specify which version of the vstats format to use. Default is @code{2}. See the
- @ref{vstats_file_format,,vstats file format} section for the format description.
- @item -vtag @var{fourcc/tag} (@emph{output})
- Force video tag/fourcc. This is an alias for @code{-tag:v}.
- @item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{output,per-stream})
- @item -force_key_frames[:@var{stream_specifier}] expr:@var{expr} (@emph{output,per-stream})
- @item -force_key_frames[:@var{stream_specifier}] source (@emph{output,per-stream})
- @var{force_key_frames} can take arguments of the following form:
- @table @option
- @item @var{time}[,@var{time}...]
- If the argument consists of timestamps, ffmpeg will round the specified times to the nearest
- output timestamp as per the encoder time base and force a keyframe at the first frame having
- timestamp equal or greater than the computed timestamp. Note that if the encoder time base is too
- coarse, then the keyframes may be forced on frames with timestamps lower than the specified time.
- The default encoder time base is the inverse of the output framerate but may be set otherwise
- via @code{-enc_time_base}.
- If one of the times is "@code{chapters}[@var{delta}]", it is expanded into
- the time of the beginning of all chapters in the file, shifted by
- @var{delta}, expressed as a time in seconds.
- This option can be useful to ensure that a seek point is present at a
- chapter mark or any other designated place in the output file.
- For example, to insert a key frame at 5 minutes, plus key frames 0.1 second
- before the beginning of every chapter:
- @example
- -force_key_frames 0:05:00,chapters-0.1
- @end example
- @item expr:@var{expr}
- If the argument is prefixed with @code{expr:}, the string @var{expr}
- is interpreted like an expression and is evaluated for each frame. A
- key frame is forced in case the evaluation is non-zero.
- The expression in @var{expr} can contain the following constants:
- @table @option
- @item n
- the number of current processed frame, starting from 0
- @item n_forced
- the number of forced frames
- @item prev_forced_n
- the number of the previous forced frame, it is @code{NAN} when no
- keyframe was forced yet
- @item prev_forced_t
- the time of the previous forced frame, it is @code{NAN} when no
- keyframe was forced yet
- @item t
- the time of the current processed frame
- @end table
- For example to force a key frame every 5 seconds, you can specify:
- @example
- -force_key_frames expr:gte(t,n_forced*5)
- @end example
- To force a key frame 5 seconds after the time of the last forced one,
- starting from second 13:
- @example
- -force_key_frames expr:if(isnan(prev_forced_t),gte(t,13),gte(t,prev_forced_t+5))
- @end example
- @item source
- If the argument is @code{source}, ffmpeg will force a key frame if
- the current frame being encoded is marked as a key frame in its source.
- In cases where this particular source frame has to be dropped,
- enforce the next available frame to become a key frame instead.
- @end table
- Note that forcing too many keyframes is very harmful for the lookahead
- algorithms of certain encoders: using fixed-GOP options or similar
- would be more efficient.
- @item -copyinkf[:@var{stream_specifier}] (@emph{output,per-stream})
- When doing stream copy, copy also non-key frames found at the
- beginning.
- @item -init_hw_device @var{type}[=@var{name}][:@var{device}[,@var{key=value}...]]
- Initialise a new hardware device of type @var{type} called @var{name}, using the
- given device parameters.
- If no name is specified it will receive a default name of the form "@var{type}%d".
- The meaning of @var{device} and the following arguments depends on the
- device type:
- @table @option
- @item cuda
- @var{device} is the number of the CUDA device.
- The following options are recognized:
- @table @option
- @item primary_ctx
- If set to 1, uses the primary device context instead of creating a new one.
- @end table
- Examples:
- @table @emph
- @item -init_hw_device cuda:1
- Choose the second device on the system.
- @item -init_hw_device cuda:0,primary_ctx=1
- Choose the first device and use the primary device context.
- @end table
- @item dxva2
- @var{device} is the number of the Direct3D 9 display adapter.
- @item d3d11va
- @var{device} is the number of the Direct3D 11 display adapter.
- If not specified, it will attempt to use the default Direct3D 11 display adapter
- or the first Direct3D 11 display adapter whose hardware VendorId is specified
- by @samp{vendor_id}.
- Examples:
- @table @emph
- @item -init_hw_device d3d11va
- Create a d3d11va device on the default Direct3D 11 display adapter.
- @item -init_hw_device d3d11va:1
- Create a d3d11va device on the Direct3D 11 display adapter specified by index 1.
- @item -init_hw_device d3d11va:,vendor_id=0x8086
- Create a d3d11va device on the first Direct3D 11 display adapter whose hardware VendorId is 0x8086.
- @end table
- @item vaapi
- @var{device} is either an X11 display name, a DRM render node or a DirectX adapter index.
- If not specified, it will attempt to open the default X11 display (@emph{$DISPLAY})
- and then the first DRM render node (@emph{/dev/dri/renderD128}), or the default
- DirectX adapter on Windows.
- The following options are recognized:
- @table @option
- @item kernel_driver
- When @var{device} is not specified, use this option to specify the name of the kernel
- driver associated with the desired device. This option is available only when
- the hardware acceleration method @emph{drm} and @emph{vaapi} are enabled.
- @end table
- Examples:
- @table @emph
- @item -init_hw_device vaapi
- Create a vaapi device on the default device.
- @item -init_hw_device vaapi:/dev/dri/renderD129
- Create a vaapi device on DRM render node @file{/dev/dri/renderD129}.
- @item -init_hw_device vaapi:1
- Create a vaapi device on DirectX adapter 1.
- @item -init_hw_device vaapi:,kernel_driver=i915
- Create a vaapi device on a device associated with kernel driver @samp{i915}.
- @end table
- @item vdpau
- @var{device} is an X11 display name.
- If not specified, it will attempt to open the default X11 display (@emph{$DISPLAY}).
- @item qsv
- @var{device} selects a value in @samp{MFX_IMPL_*}. Allowed values are:
- @table @option
- @item auto
- @item sw
- @item hw
- @item auto_any
- @item hw_any
- @item hw2
- @item hw3
- @item hw4
- @end table
- If not specified, @samp{auto_any} is used.
- (Note that it may be easier to achieve the desired result for QSV by creating the
- platform-appropriate subdevice (@samp{dxva2} or @samp{d3d11va} or @samp{vaapi}) and then deriving a
- QSV device from that.)
- The following options are recognized:
- @table @option
- @item child_device
- Specify a DRM render node on Linux or DirectX adapter on Windows.
- @item child_device_type
- Choose platform-appropriate subdevice type. On Windows @samp{d3d11va} is used
- as default subdevice type when @code{--enable-libvpl} is specified at configuration time,
- @samp{dxva2} is used as default subdevice type when @code{--enable-libmfx} is specified at
- configuration time. On Linux user can use @samp{vaapi} only as subdevice type.
- @end table
- Examples:
- @table @emph
- @item -init_hw_device qsv:hw,child_device=/dev/dri/renderD129
- Create a QSV device with @samp{MFX_IMPL_HARDWARE} on DRM render node @file{/dev/dri/renderD129}.
- @item -init_hw_device qsv:hw,child_device=1
- Create a QSV device with @samp{MFX_IMPL_HARDWARE} on DirectX adapter 1.
- @item -init_hw_device qsv:hw,child_device_type=d3d11va
- Choose the GPU subdevice with type @samp{d3d11va} and create QSV device with @samp{MFX_IMPL_HARDWARE}.
- @item -init_hw_device qsv:hw,child_device_type=dxva2
- Choose the GPU subdevice with type @samp{dxva2} and create QSV device with @samp{MFX_IMPL_HARDWARE}.
- @item -init_hw_device qsv:hw,child_device=1,child_device_type=d3d11va
- Create a QSV device with @samp{MFX_IMPL_HARDWARE} on DirectX adapter 1 with subdevice type @samp{d3d11va}.
- @item -init_hw_device vaapi=va:/dev/dri/renderD129 -init_hw_device qsv=hw1@@@var{va}
- Create a VAAPI device called @samp{va} on @file{/dev/dri/renderD129}, then derive a QSV device called @samp{hw1}
- from device @samp{va}.
- @end table
- @item opencl
- @var{device} selects the platform and device as @emph{platform_index.device_index}.
- The set of devices can also be filtered using the key-value pairs to find only
- devices matching particular platform or device strings.
- The strings usable as filters are:
- @table @option
- @item platform_profile
- @item platform_version
- @item platform_name
- @item platform_vendor
- @item platform_extensions
- @item device_name
- @item device_vendor
- @item driver_version
- @item device_version
- @item device_profile
- @item device_extensions
- @item device_type
- @end table
- The indices and filters must together uniquely select a device.
- Examples:
- @table @emph
- @item -init_hw_device opencl:0.1
- Choose the second device on the first platform.
- @item -init_hw_device opencl:,device_name=Foo9000
- Choose the device with a name containing the string @emph{Foo9000}.
- @item -init_hw_device opencl:1,device_type=gpu,device_extensions=cl_khr_fp16
- Choose the GPU device on the second platform supporting the @emph{cl_khr_fp16}
- extension.
- @end table
- @item vulkan
- If @var{device} is an integer, it selects the device by its index in a
- system-dependent list of devices. If @var{device} is any other string, it
- selects the first device with a name containing that string as a substring.
- The following options are recognized:
- @table @option
- @item debug
- If set to 1, enables the validation layer, if installed.
- @item linear_images
- If set to 1, images allocated by the hwcontext will be linear and locally mappable.
- @item instance_extensions
- A plus separated list of additional instance extensions to enable.
- @item device_extensions
- A plus separated list of additional device extensions to enable.
- @end table
- Examples:
- @table @emph
- @item -init_hw_device vulkan:1
- Choose the second device on the system.
- @item -init_hw_device vulkan:RADV
- Choose the first device with a name containing the string @emph{RADV}.
- @item -init_hw_device vulkan:0,instance_extensions=VK_KHR_wayland_surface+VK_KHR_xcb_surface
- Choose the first device and enable the Wayland and XCB instance extensions.
- @end table
- @end table
- @item -init_hw_device @var{type}[=@var{name}]@@@var{source}
- Initialise a new hardware device of type @var{type} called @var{name},
- deriving it from the existing device with the name @var{source}.
- @item -init_hw_device list
- List all hardware device types supported in this build of ffmpeg.
- @item -filter_hw_device @var{name}
- Pass the hardware device called @var{name} to all filters in any filter graph.
- This can be used to set the device to upload to with the @code{hwupload} filter,
- or the device to map to with the @code{hwmap} filter. Other filters may also
- make use of this parameter when they require a hardware device. Note that this
- is typically only required when the input is not already in hardware frames -
- when it is, filters will derive the device they require from the context of the
- frames they receive as input.
- This is a global setting, so all filters will receive the same device.
- @item -hwaccel[:@var{stream_specifier}] @var{hwaccel} (@emph{input,per-stream})
- Use hardware acceleration to decode the matching stream(s). The allowed values
- of @var{hwaccel} are:
- @table @option
- @item none
- Do not use any hardware acceleration (the default).
- @item auto
- Automatically select the hardware acceleration method.
- @item vdpau
- Use VDPAU (Video Decode and Presentation API for Unix) hardware acceleration.
- @item dxva2
- Use DXVA2 (DirectX Video Acceleration) hardware acceleration.
- @item d3d11va
- Use D3D11VA (DirectX Video Acceleration) hardware acceleration.
- @item vaapi
- Use VAAPI (Video Acceleration API) hardware acceleration.
- @item qsv
- Use the Intel QuickSync Video acceleration for video transcoding.
- Unlike most other values, this option does not enable accelerated decoding (that
- is used automatically whenever a qsv decoder is selected), but accelerated
- transcoding, without copying the frames into the system memory.
- For it to work, both the decoder and the encoder must support QSV acceleration
- and no filters must be used.
- @end table
- This option has no effect if the selected hwaccel is not available or not
- supported by the chosen decoder.
- Note that most acceleration methods are intended for playback and will not be
- faster than software decoding on modern CPUs. Additionally, @command{ffmpeg}
- will usually need to copy the decoded frames from the GPU memory into the system
- memory, resulting in further performance loss. This option is thus mainly
- useful for testing.
- @item -hwaccel_device[:@var{stream_specifier}] @var{hwaccel_device} (@emph{input,per-stream})
- Select a device to use for hardware acceleration.
- This option only makes sense when the @option{-hwaccel} option is also specified.
- It can either refer to an existing device created with @option{-init_hw_device}
- by name, or it can create a new device as if
- @samp{-init_hw_device} @var{type}:@var{hwaccel_device}
- were called immediately before.
- @item -hwaccels
- List all hardware acceleration components enabled in this build of ffmpeg.
- Actual runtime availability depends on the hardware and its suitable driver
- being installed.
- @item -fix_sub_duration_heartbeat[:@var{stream_specifier}]
- Set a specific output video stream as the heartbeat stream according to which
- to split and push through currently in-progress subtitle upon receipt of a
- random access packet.
- This lowers the latency of subtitles for which the end packet or the following
- subtitle has not yet been received. As a drawback, this will most likely lead
- to duplication of subtitle events in order to cover the full duration, so
- when dealing with use cases where latency of when the subtitle event is passed
- on to output is not relevant this option should not be utilized.
- Requires @option{-fix_sub_duration} to be set for the relevant input subtitle
- stream for this to have any effect, as well as for the input subtitle stream
- having to be directly mapped to the same output in which the heartbeat stream
- resides.
- @end table
- @section Audio Options
- @table @option
- @item -aframes @var{number} (@emph{output})
- Set the number of audio frames to output. This is an obsolete alias for
- @code{-frames:a}, which you should use instead.
- @item -ar[:@var{stream_specifier}] @var{freq} (@emph{input/output,per-stream})
- Set the audio sampling frequency. For output streams it is set by
- default to the frequency of the corresponding input stream. For input
- streams this option only makes sense for audio grabbing devices and raw
- demuxers and is mapped to the corresponding demuxer options.
- @item -aq @var{q} (@emph{output})
- Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
- @item -ac[:@var{stream_specifier}] @var{channels} (@emph{input/output,per-stream})
- Set the number of audio channels. For output streams it is set by
- default to the number of input audio channels. For input streams
- this option only makes sense for audio grabbing devices and raw demuxers
- and is mapped to the corresponding demuxer options.
- @item -an (@emph{input/output})
- As an input option, blocks all audio streams of a file from being filtered or
- being automatically selected or mapped for any output. See @code{-discard}
- option to disable streams individually.
- As an output option, disables audio recording i.e. automatic selection or
- mapping of any audio stream. For full manual control see the @code{-map}
- option.
- @item -acodec @var{codec} (@emph{input/output})
- Set the audio codec. This is an alias for @code{-codec:a}.
- @item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream})
- Set the audio sample format. Use @code{-sample_fmts} to get a list
- of supported sample formats.
- @item -af @var{filtergraph} (@emph{output})
- Create the filtergraph specified by @var{filtergraph} and use it to
- filter the stream.
- This is an alias for @code{-filter:a}, see the @ref{filter_option,,-filter option}.
- @end table
- @section Advanced Audio options
- @table @option
- @item -atag @var{fourcc/tag} (@emph{output})
- Force audio tag/fourcc. This is an alias for @code{-tag:a}.
- @item -ch_layout[:@var{stream_specifier}] @var{layout} (@emph{input/output,per-stream})
- Alias for @code{-channel_layout}.
- @item -channel_layout[:@var{stream_specifier}] @var{layout} (@emph{input/output,per-stream})
- Set the audio channel layout. For output streams it is set by default to the
- input channel layout. For input streams it overrides the channel layout of the
- input. Not all decoders respect the overridden channel layout. This option
- also sets the channel layout for audio grabbing devices and raw demuxers
- and is mapped to the corresponding demuxer option.
- @item -guess_layout_max @var{channels} (@emph{input,per-stream})
- If some input channel layout is not known, try to guess only if it
- corresponds to at most the specified number of channels. For example, 2
- tells to @command{ffmpeg} to recognize 1 channel as mono and 2 channels as
- stereo but not 6 channels as 5.1. The default is to always try to guess. Use
- 0 to disable all guessing. Using the @code{-channel_layout} option to
- explicitly specify an input layout also disables guessing.
- @end table
- @section Subtitle options
- @table @option
- @item -scodec @var{codec} (@emph{input/output})
- Set the subtitle codec. This is an alias for @code{-codec:s}.
- @item -sn (@emph{input/output})
- As an input option, blocks all subtitle streams of a file from being filtered or
- being automatically selected or mapped for any output. See @code{-discard}
- option to disable streams individually.
- As an output option, disables subtitle recording i.e. automatic selection or
- mapping of any subtitle stream. For full manual control see the @code{-map}
- option.
- @end table
- @section Advanced Subtitle options
- @table @option
- @item -fix_sub_duration
- Fix subtitles durations. For each subtitle, wait for the next packet in the
- same stream and adjust the duration of the first to avoid overlap. This is
- necessary with some subtitles codecs, especially DVB subtitles, because the
- duration in the original packet is only a rough estimate and the end is
- actually marked by an empty subtitle frame. Failing to use this option when
- necessary can result in exaggerated durations or muxing failures due to
- non-monotonic timestamps.
- Note that this option will delay the output of all data until the next
- subtitle packet is decoded: it may increase memory consumption and latency a
- lot.
- @item -canvas_size @var{size}
- Set the size of the canvas used to render subtitles.
- @end table
- @section Advanced options
- @table @option
- @item -map [-]@var{input_file_id}[:@var{stream_specifier}][?] | @var{[linklabel]} (@emph{output})
- Create one or more streams in the output file. This option has two forms for
- specifying the data source(s): the first selects one or more streams from some
- input file (specified with @code{-i}), the second takes an output from some
- complex filtergraph (specified with @code{-filter_complex}).
- In the first form, an output stream is created for every stream from the input
- file with the index @var{input_file_id}. If @var{stream_specifier} is given,
- only those streams that match the specifier are used (see the
- @ref{Stream specifiers} section for the @var{stream_specifier} syntax).
- A @code{-} character before the stream identifier creates a "negative" mapping.
- It disables matching streams from already created mappings.
- A trailing @code{?} after the stream index will allow the map to be
- optional: if the map matches no streams the map will be ignored instead
- of failing. Note the map will still fail if an invalid input file index
- is used; such as if the map refers to a non-existent input.
- An alternative @var{[linklabel]} form will map outputs from complex filter
- graphs (see the @option{-filter_complex} option) to the output file.
- @var{linklabel} must correspond to a defined output link label in the graph.
- This option may be specified multiple times, each adding more streams to the
- output file. Any given input stream may also be mapped any number of times as a
- source for different output streams, e.g. in order to use different encoding
- options and/or filters. The streams are created in the output in the same order
- in which the @code{-map} options are given on the commandline.
- Using this option disables the default mappings for this output file.
- Examples:
- @table @emph
- @item map everything
- To map ALL streams from the first input file to output
- @example
- ffmpeg -i INPUT -map 0 output
- @end example
- @item select specific stream
- If you have two audio streams in the first input file, these streams are
- identified by @var{0:0} and @var{0:1}. You can use @code{-map} to select which
- streams to place in an output file. For example:
- @example
- ffmpeg -i INPUT -map 0:1 out.wav
- @end example
- will map the second input stream in @file{INPUT} to the (single) output stream
- in @file{out.wav}.
- @item create multiple streams
- To select the stream with index 2 from input file @file{a.mov} (specified by the
- identifier @var{0:2}), and stream with index 6 from input @file{b.mov}
- (specified by the identifier @var{1:6}), and copy them to the output file
- @file{out.mov}:
- @example
- ffmpeg -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
- @end example
- @item create multiple streams 2
- To select all video and the third audio stream from an input file:
- @example
- ffmpeg -i INPUT -map 0:v -map 0:a:2 OUTPUT
- @end example
- @item negative map
- To map all the streams except the second audio, use negative mappings
- @example
- ffmpeg -i INPUT -map 0 -map -0:a:1 OUTPUT
- @end example
- @item optional map
- To map the video and audio streams from the first input, and using the
- trailing @code{?}, ignore the audio mapping if no audio streams exist in
- the first input:
- @example
- ffmpeg -i INPUT -map 0:v -map 0:a? OUTPUT
- @end example
- @item map by language
- To pick the English audio stream:
- @example
- ffmpeg -i INPUT -map 0:m:language:eng OUTPUT
- @end example
- @end table
- @item -ignore_unknown
- Ignore input streams with unknown type instead of failing if copying
- such streams is attempted.
- @item -copy_unknown
- Allow input streams with unknown type to be copied instead of failing if copying
- such streams is attempted.
- @item -map_metadata[:@var{metadata_spec_out}] @var{infile}[:@var{metadata_spec_in}] (@emph{output,per-metadata})
- Set metadata information of the next output file from @var{infile}. Note that
- those are file indices (zero-based), not filenames.
- Optional @var{metadata_spec_in/out} parameters specify, which metadata to copy.
- A metadata specifier can have the following forms:
- @table @option
- @item @var{g}
- global metadata, i.e. metadata that applies to the whole file
- @item @var{s}[:@var{stream_spec}]
- per-stream metadata. @var{stream_spec} is a stream specifier as described
- in the @ref{Stream specifiers} chapter. In an input metadata specifier, the first
- matching stream is copied from. In an output metadata specifier, all matching
- streams are copied to.
- @item @var{c}:@var{chapter_index}
- per-chapter metadata. @var{chapter_index} is the zero-based chapter index.
- @item @var{p}:@var{program_index}
- per-program metadata. @var{program_index} is the zero-based program index.
- @end table
- If metadata specifier is omitted, it defaults to global.
- By default, global metadata is copied from the first input file,
- per-stream and per-chapter metadata is copied along with streams/chapters. These
- default mappings are disabled by creating any mapping of the relevant type. A negative
- file index can be used to create a dummy mapping that just disables automatic copying.
- For example to copy metadata from the first stream of the input file to global metadata
- of the output file:
- @example
- ffmpeg -i in.ogg -map_metadata 0:s:0 out.mp3
- @end example
- To do the reverse, i.e. copy global metadata to all audio streams:
- @example
- ffmpeg -i in.mkv -map_metadata:s:a 0:g out.mkv
- @end example
- Note that simple @code{0} would work as well in this example, since global
- metadata is assumed by default.
- @item -map_chapters @var{input_file_index} (@emph{output})
- Copy chapters from input file with index @var{input_file_index} to the next
- output file. If no chapter mapping is specified, then chapters are copied from
- the first input file with at least one chapter. Use a negative file index to
- disable any chapter copying.
- @item -benchmark (@emph{global})
- Show benchmarking information at the end of an encode.
- Shows real, system and user time used and maximum memory consumption.
- Maximum memory consumption is not supported on all systems,
- it will usually display as 0 if not supported.
- @item -benchmark_all (@emph{global})
- Show benchmarking information during the encode.
- Shows real, system and user time used in various steps (audio/video encode/decode).
- @item -timelimit @var{duration} (@emph{global})
- Exit after ffmpeg has been running for @var{duration} seconds in CPU user time.
- @item -dump (@emph{global})
- Dump each input packet to stderr.
- @item -hex (@emph{global})
- When dumping packets, also dump the payload.
- @item -readrate @var{speed} (@emph{input})
- Limit input read speed.
- Its value is a floating-point positive number which represents the maximum duration of
- media, in seconds, that should be ingested in one second of wallclock time.
- Default value is zero and represents no imposed limitation on speed of ingestion.
- Value @code{1} represents real-time speed and is equivalent to @code{-re}.
- Mainly used to simulate a capture device or live input stream (e.g. when reading from a file).
- Should not be used with a low value when input is an actual capture device or live stream as
- it may cause packet loss.
- It is useful for when flow speed of output packets is important, such as live streaming.
- @item -re (@emph{input})
- Read input at native frame rate. This is equivalent to setting @code{-readrate 1}.
- @item -readrate_initial_burst @var{seconds}
- Set an initial read burst time, in seconds, after which @option{-re/-readrate}
- will be enforced.
- @item -vsync @var{parameter} (@emph{global})
- @itemx -fps_mode[:@var{stream_specifier}] @var{parameter} (@emph{output,per-stream})
- Set video sync method / framerate mode. vsync is applied to all output video streams
- but can be overridden for a stream by setting fps_mode. vsync is deprecated and will be
- removed in the future.
- For compatibility reasons some of the values for vsync can be specified as numbers (shown
- in parentheses in the following table).
- @table @option
- @item passthrough (0)
- Each frame is passed with its timestamp from the demuxer to the muxer.
- @item cfr (1)
- Frames will be duplicated and dropped to achieve exactly the requested
- constant frame rate.
- @item vfr (2)
- Frames are passed through with their timestamp or dropped so as to
- prevent 2 frames from having the same timestamp.
- @item auto (-1)
- Chooses between cfr and vfr depending on muxer capabilities. This is the
- default method.
- @end table
- Note that the timestamps may be further modified by the muxer, after this.
- For example, in the case that the format option @option{avoid_negative_ts}
- is enabled.
- With -map you can select from which stream the timestamps should be
- taken. You can leave either video or audio unchanged and sync the
- remaining stream(s) to the unchanged one.
- @item -frame_drop_threshold @var{parameter}
- Frame drop threshold, which specifies how much behind video frames can
- be before they are dropped. In frame rate units, so 1.0 is one frame.
- The default is -1.1. One possible usecase is to avoid framedrops in case
- of noisy timestamps or to increase frame drop precision in case of exact
- timestamps.
- @item -apad @var{parameters} (@emph{output,per-stream})
- Pad the output audio stream(s). This is the same as applying @code{-af apad}.
- Argument is a string of filter parameters composed the same as with the @code{apad} filter.
- @code{-shortest} must be set for this output for the option to take effect.
- @item -copyts
- Do not process input timestamps, but keep their values without trying
- to sanitize them. In particular, do not remove the initial start time
- offset value.
- Note that, depending on the @option{vsync} option or on specific muxer
- processing (e.g. in case the format option @option{avoid_negative_ts}
- is enabled) the output timestamps may mismatch with the input
- timestamps even when this option is selected.
- @item -start_at_zero
- When used with @option{copyts}, shift input timestamps so they start at zero.
- This means that using e.g. @code{-ss 50} will make output timestamps start at
- 50 seconds, regardless of what timestamp the input file started at.
- @item -copytb @var{mode}
- Specify how to set the encoder timebase when stream copying. @var{mode} is an
- integer numeric value, and can assume one of the following values:
- @table @option
- @item 1
- Use the demuxer timebase.
- The time base is copied to the output encoder from the corresponding input
- demuxer. This is sometimes required to avoid non monotonically increasing
- timestamps when copying video streams with variable frame rate.
- @item 0
- Use the decoder timebase.
- The time base is copied to the output encoder from the corresponding input
- decoder.
- @item -1
- Try to make the choice automatically, in order to generate a sane output.
- @end table
- Default value is -1.
- @item -enc_time_base[:@var{stream_specifier}] @var{timebase} (@emph{output,per-stream})
- Set the encoder timebase. @var{timebase} can assume one of the following values:
- @table @option
- @item 0
- Assign a default value according to the media type.
- For video - use 1/framerate, for audio - use 1/samplerate.
- @item demux
- Use the timebase from the demuxer.
- @item filter
- Use the timebase from the filtergraph.
- @item a positive number
- Use the provided number as the timebase.
- This field can be provided as a ratio of two integers (e.g. 1:24, 1:48000)
- or as a decimal number (e.g. 0.04166, 2.0833e-5)
- @end table
- Default value is 0.
- @item -bitexact (@emph{input/output})
- Enable bitexact mode for (de)muxer and (de/en)coder
- @item -shortest (@emph{output})
- Finish encoding when the shortest output stream ends.
- Note that this option may require buffering frames, which introduces extra
- latency. The maximum amount of this latency may be controlled with the
- @code{-shortest_buf_duration} option.
- @item -shortest_buf_duration @var{duration} (@emph{output})
- The @code{-shortest} option may require buffering potentially large amounts
- of data when at least one of the streams is "sparse" (i.e. has large gaps
- between frames – this is typically the case for subtitles).
- This option controls the maximum duration of buffered frames in seconds.
- Larger values may allow the @code{-shortest} option to produce more accurate
- results, but increase memory use and latency.
- The default value is 10 seconds.
- @item -dts_delta_threshold @var{threshold}
- Timestamp discontinuity delta threshold, expressed as a decimal number
- of seconds.
- The timestamp discontinuity correction enabled by this option is only
- applied to input formats accepting timestamp discontinuity (for which
- the @code{AVFMT_TS_DISCONT} flag is enabled), e.g. MPEG-TS and HLS, and
- is automatically disabled when employing the @code{-copyts} option
- (unless wrapping is detected).
- If a timestamp discontinuity is detected whose absolute value is
- greater than @var{threshold}, ffmpeg will remove the discontinuity by
- decreasing/increasing the current DTS and PTS by the corresponding
- delta value.
- The default value is 10.
- @item -dts_error_threshold @var{threshold}
- Timestamp error delta threshold, expressed as a decimal number of
- seconds.
- The timestamp correction enabled by this option is only applied to
- input formats not accepting timestamp discontinuity (for which the
- @code{AVFMT_TS_DISCONT} flag is not enabled).
- If a timestamp discontinuity is detected whose absolute value is
- greater than @var{threshold}, ffmpeg will drop the PTS/DTS timestamp
- value.
- The default value is @code{3600*30} (30 hours), which is arbitrarily
- picked and quite conservative.
- @item -muxdelay @var{seconds} (@emph{output})
- Set the maximum demux-decode delay.
- @item -muxpreload @var{seconds} (@emph{output})
- Set the initial demux-decode delay.
- @item -streamid @var{output-stream-index}:@var{new-value} (@emph{output})
- Assign a new stream-id value to an output stream. This option should be
- specified prior to the output filename to which it applies.
- For the situation where multiple output files exist, a streamid
- may be reassigned to a different value.
- For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
- an output mpegts file:
- @example
- ffmpeg -i inurl -streamid 0:33 -streamid 1:36 out.ts
- @end example
- @item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{input/output,per-stream})
- Apply bitstream filters to matching streams. The filters are applied to each
- packet as it is received from the demuxer (when used as an input option) or
- before it is sent to the muxer (when used as an output option).
- @var{bitstream_filters} is a comma-separated list of bitstream filter
- specifications, each of the form
- @example
- @var{filter}[=@var{optname0}=@var{optval0}:@var{optname1}=@var{optval1}:...]
- @end example
- Any of the ',=:' characters that are to be a part of an option value need to be
- escaped with a backslash.
- Use the @code{-bsfs} option to get the list of bitstream filters.
- E.g.
- @example
- ffmpeg -bsf:v h264_mp4toannexb -i h264.mp4 -c:v copy -an out.h264
- @end example
- applies the @code{h264_mp4toannexb} bitstream filter (which converts
- MP4-encapsulated H.264 stream to Annex B) to the @emph{input} video stream.
- On the other hand,
- @example
- ffmpeg -i file.mov -an -vn -bsf:s mov2textsub -c:s copy -f rawvideo sub.txt
- @end example
- applies the @code{mov2textsub} bitstream filter (which extracts text from MOV
- subtitles) to the @emph{output} subtitle stream. Note, however, that since both
- examples use @code{-c copy}, it matters little whether the filters are applied
- on input or output - that would change if transcoding was happening.
- @item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{input/output,per-stream})
- Force a tag/fourcc for matching streams.
- @item -timecode @var{hh}:@var{mm}:@var{ss}SEP@var{ff}
- Specify Timecode for writing. @var{SEP} is ':' for non drop timecode and ';'
- (or '.') for drop.
- @example
- ffmpeg -i input.mpg -timecode 01:02:03.04 -r 30000/1001 -s ntsc output.mpg
- @end example
- @anchor{filter_complex_option}
- @item -filter_complex @var{filtergraph} (@emph{global})
- Define a complex filtergraph, i.e. one with arbitrary number of inputs and/or
- outputs. For simple graphs -- those with one input and one output of the same
- type -- see the @option{-filter} options. @var{filtergraph} is a description of
- the filtergraph, as described in the ``Filtergraph syntax'' section of the
- ffmpeg-filters manual. This option may be specified multiple times - each use
- creates a new complex filtergraph.
- Inputs to a complex filtergraph may come from different source types,
- distinguished by the format of the corresponding link label:
- @itemize
- @item
- To connect an input stream, use @code{[file_index:stream_specifier]} (i.e. the
- same syntax as @option{-map}). If @var{stream_specifier} matches multiple
- streams, the first one will be used.
- @item
- To connect a loopback decoder use [dec:@var{dec_idx}], where @var{dec_idx} is
- the index of the loopback decoder to be connected to given input.
- @item
- To connect an output from another complex filtergraph, use its link label. E.g
- the following example:
- @example
- ffmpeg -i input.mkv \
- -filter_complex '[0:v]scale=size=hd1080,split=outputs=2[for_enc][orig_scaled]' \
- -c:v libx264 -map '[for_enc]' output.mkv \
- -dec 0:0 \
- -filter_complex '[dec:0][orig_scaled]hstack[stacked]' \
- -map '[stacked]' -c:v ffv1 comparison.mkv
- @end example
- reads an input video and
- @itemize
- @item
- (line 2) uses a complex filtergraph with one input and two outputs
- to scale the video to 1920x1080 and duplicate the result to both
- outputs;
- @item
- (line 3) encodes one scaled output with @code{libx264} and writes the result to
- @file{output.mkv};
- @item
- (line 4) decodes this encoded stream with a loopback decoder;
- @item
- (line 5) places the output of the loopback decoder (i.e. the
- @code{libx264}-encoded video) side by side with the scaled original input;
- @item
- (line 6) combined video is then losslessly encoded and written into
- @file{comparison.mkv}.
- @end itemize
- Note that the two filtergraphs cannot be combined into one, because then there
- would be a cycle in the transcoding pipeline (filtergraph output goes to
- encoding, from there to decoding, then back to the same graph), and such cycles
- are not allowed.
- @end itemize
- An unlabeled input will be connected to the first unused input stream of the
- matching type.
- Output link labels are referred to with @option{-map}. Unlabeled outputs are
- added to the first output file.
- Note that with this option it is possible to use only lavfi sources without
- normal input files.
- For example, to overlay an image over video
- @example
- ffmpeg -i video.mkv -i image.png -filter_complex '[0:v][1:v]overlay[out]' -map
- '[out]' out.mkv
- @end example
- Here @code{[0:v]} refers to the first video stream in the first input file,
- which is linked to the first (main) input of the overlay filter. Similarly the
- first video stream in the second input is linked to the second (overlay) input
- of overlay.
- Assuming there is only one video stream in each input file, we can omit input
- labels, so the above is equivalent to
- @example
- ffmpeg -i video.mkv -i image.png -filter_complex 'overlay[out]' -map
- '[out]' out.mkv
- @end example
- Furthermore we can omit the output label and the single output from the filter
- graph will be added to the output file automatically, so we can simply write
- @example
- ffmpeg -i video.mkv -i image.png -filter_complex 'overlay' out.mkv
- @end example
- As a special exception, you can use a bitmap subtitle stream as input: it
- will be converted into a video with the same size as the largest video in
- the file, or 720x576 if no video is present. Note that this is an
- experimental and temporary solution. It will be removed once libavfilter has
- proper support for subtitles.
- For example, to hardcode subtitles on top of a DVB-T recording stored in
- MPEG-TS format, delaying the subtitles by 1 second:
- @example
- ffmpeg -i input.ts -filter_complex \
- '[#0x2ef] setpts=PTS+1/TB [sub] ; [#0x2d0] [sub] overlay' \
- -sn -map '#0x2dc' output.mkv
- @end example
- (0x2d0, 0x2dc and 0x2ef are the MPEG-TS PIDs of respectively the video,
- audio and subtitles streams; 0:0, 0:3 and 0:7 would have worked too)
- To generate 5 seconds of pure red video using lavfi @code{color} source:
- @example
- ffmpeg -filter_complex 'color=c=red' -t 5 out.mkv
- @end example
- @item -filter_complex_threads @var{nb_threads} (@emph{global})
- Defines how many threads are used to process a filter_complex graph.
- Similar to filter_threads but used for @code{-filter_complex} graphs only.
- The default is the number of available CPUs.
- @item -lavfi @var{filtergraph} (@emph{global})
- Define a complex filtergraph, i.e. one with arbitrary number of inputs and/or
- outputs. Equivalent to @option{-filter_complex}.
- @item -accurate_seek (@emph{input})
- This option enables or disables accurate seeking in input files with the
- @option{-ss} option. It is enabled by default, so seeking is accurate when
- transcoding. Use @option{-noaccurate_seek} to disable it, which may be useful
- e.g. when copying some streams and transcoding the others.
- @item -seek_timestamp (@emph{input})
- This option enables or disables seeking by timestamp in input files with the
- @option{-ss} option. It is disabled by default. If enabled, the argument
- to the @option{-ss} option is considered an actual timestamp, and is not
- offset by the start time of the file. This matters only for files which do
- not start from timestamp 0, such as transport streams.
- @item -thread_queue_size @var{size} (@emph{input/output})
- For input, this option sets the maximum number of queued packets when reading
- from the file or device. With low latency / high rate live streams, packets may
- be discarded if they are not read in a timely manner; setting this value can
- force ffmpeg to use a separate input thread and read packets as soon as they
- arrive. By default ffmpeg only does this if multiple inputs are specified.
- For output, this option specified the maximum number of packets that may be
- queued to each muxing thread.
- @item -sdp_file @var{file} (@emph{global})
- Print sdp information for an output stream to @var{file}.
- This allows dumping sdp information when at least one output isn't an
- rtp stream. (Requires at least one of the output formats to be rtp).
- @item -discard (@emph{input})
- Allows discarding specific streams or frames from streams.
- Any input stream can be fully discarded, using value @code{all} whereas
- selective discarding of frames from a stream occurs at the demuxer
- and is not supported by all demuxers.
- @table @option
- @item none
- Discard no frame.
- @item default
- Default, which discards no frames.
- @item noref
- Discard all non-reference frames.
- @item bidir
- Discard all bidirectional frames.
- @item nokey
- Discard all frames excepts keyframes.
- @item all
- Discard all frames.
- @end table
- @item -abort_on @var{flags} (@emph{global})
- Stop and abort on various conditions. The following flags are available:
- @table @option
- @item empty_output
- No packets were passed to the muxer, the output is empty.
- @item empty_output_stream
- No packets were passed to the muxer in some of the output streams.
- @end table
- @item -max_error_rate (@emph{global})
- Set fraction of decoding frame failures across all inputs which when crossed
- ffmpeg will return exit code 69. Crossing this threshold does not terminate
- processing. Range is a floating-point number between 0 to 1. Default is 2/3.
- @item -xerror (@emph{global})
- Stop and exit on error
- @item -max_muxing_queue_size @var{packets} (@emph{output,per-stream})
- When transcoding audio and/or video streams, ffmpeg will not begin writing into
- the output until it has one packet for each such stream. While waiting for that
- to happen, packets for other streams are buffered. This option sets the size of
- this buffer, in packets, for the matching output stream.
- The default value of this option should be high enough for most uses, so only
- touch this option if you are sure that you need it.
- @item -muxing_queue_data_threshold @var{bytes} (@emph{output,per-stream})
- This is a minimum threshold until which the muxing queue size is not taken into
- account. Defaults to 50 megabytes per stream, and is based on the overall size
- of packets passed to the muxer.
- @item -auto_conversion_filters (@emph{global})
- Enable automatically inserting format conversion filters in all filter
- graphs, including those defined by @option{-vf}, @option{-af},
- @option{-filter_complex} and @option{-lavfi}. If filter format negotiation
- requires a conversion, the initialization of the filters will fail.
- Conversions can still be performed by inserting the relevant conversion
- filter (scale, aresample) in the graph.
- On by default, to explicitly disable it you need to specify
- @code{-noauto_conversion_filters}.
- @item -bits_per_raw_sample[:@var{stream_specifier}] @var{value} (@emph{output,per-stream})
- Declare the number of bits per raw sample in the given output stream to be
- @var{value}. Note that this option sets the information provided to the
- encoder/muxer, it does not change the stream to conform to this value. Setting
- values that do not match the stream properties may result in encoding failures
- or invalid output files.
- @anchor{stats_enc_options}
- @item -stats_enc_pre[:@var{stream_specifier}] @var{path} (@emph{output,per-stream})
- @item -stats_enc_post[:@var{stream_specifier}] @var{path} (@emph{output,per-stream})
- @item -stats_mux_pre[:@var{stream_specifier}] @var{path} (@emph{output,per-stream})
- Write per-frame encoding information about the matching streams into the file
- given by @var{path}.
- @option{-stats_enc_pre} writes information about raw video or audio frames right
- before they are sent for encoding, while @option{-stats_enc_post} writes
- information about encoded packets as they are received from the encoder.
- @option{-stats_mux_pre} writes information about packets just as they are about to
- be sent to the muxer. Every frame or packet produces one line in the specified
- file. The format of this line is controlled by @option{-stats_enc_pre_fmt} /
- @option{-stats_enc_post_fmt} / @option{-stats_mux_pre_fmt}.
- When stats for multiple streams are written into a single file, the lines
- corresponding to different streams will be interleaved. The precise order of
- this interleaving is not specified and not guaranteed to remain stable between
- different invocations of the program, even with the same options.
- @item -stats_enc_pre_fmt[:@var{stream_specifier}] @var{format_spec} (@emph{output,per-stream})
- @item -stats_enc_post_fmt[:@var{stream_specifier}] @var{format_spec} (@emph{output,per-stream})
- @item -stats_mux_pre_fmt[:@var{stream_specifier}] @var{format_spec} (@emph{output,per-stream})
- Specify the format for the lines written with @option{-stats_enc_pre} /
- @option{-stats_enc_post} / @option{-stats_mux_pre}.
- @var{format_spec} is a string that may contain directives of the form
- @var{@{fmt@}}. @var{format_spec} is backslash-escaped --- use \@{, \@}, and \\
- to write a literal @{, @}, or \, respectively, into the output.
- The directives given with @var{fmt} may be one of the following:
- @table @option
- @item fidx
- Index of the output file.
- @item sidx
- Index of the output stream in the file.
- @item n
- Frame number. Pre-encoding: number of frames sent to the encoder so far.
- Post-encoding: number of packets received from the encoder so far.
- Muxing: number of packets submitted to the muxer for this stream so far.
- @item ni
- Input frame number. Index of the input frame (i.e. output by a decoder) that
- corresponds to this output frame or packet. -1 if unavailable.
- @item tb
- Timebase in which this frame/packet's timestamps are expressed, as a rational
- number @var{num/den}. Note that encoder and muxer may use different timebases.
- @item tbi
- Timebase for @var{ptsi}, as a rational number @var{num/den}. Available when
- @var{ptsi} is available, @var{0/1} otherwise.
- @item pts
- Presentation timestamp of the frame or packet, as an integer. Should be
- multiplied by the timebase to compute presentation time.
- @item ptsi
- Presentation timestamp of the input frame (see @var{ni}), as an integer. Should
- be multiplied by @var{tbi} to compute presentation time. Printed as
- (2^63 - 1 = 9223372036854775807) when not available.
- @item t
- Presentation time of the frame or packet, as a decimal number. Equal to
- @var{pts} multiplied by @var{tb}.
- @item ti
- Presentation time of the input frame (see @var{ni}), as a decimal number. Equal
- to @var{ptsi} multiplied by @var{tbi}. Printed as inf when not available.
- @item dts (@emph{packet})
- Decoding timestamp of the packet, as an integer. Should be multiplied by the
- timebase to compute presentation time.
- @item dt (@emph{packet})
- Decoding time of the frame or packet, as a decimal number. Equal to
- @var{dts} multiplied by @var{tb}.
- @item sn (@emph{frame,audio})
- Number of audio samples sent to the encoder so far.
- @item samp (@emph{frame,audio})
- Number of audio samples in the frame.
- @item size (@emph{packet})
- Size of the encoded packet in bytes.
- @item br (@emph{packet})
- Current bitrate in bits per second.
- @item abr (@emph{packet})
- Average bitrate for the whole stream so far, in bits per second, -1 if it cannot
- be determined at this point.
- @item key (@emph{packet})
- Character 'K' if the packet contains a keyframe, character 'N' otherwise.
- @end table
- Directives tagged with @emph{packet} may only be used with
- @option{-stats_enc_post_fmt} and @option{-stats_mux_pre_fmt}.
- Directives tagged with @emph{frame} may only be used with
- @option{-stats_enc_pre_fmt}.
- Directives tagged with @emph{audio} may only be used with audio streams.
- The default format strings are:
- @table @option
- @item pre-encoding
- @{fidx@} @{sidx@} @{n@} @{t@}
- @item post-encoding
- @{fidx@} @{sidx@} @{n@} @{t@}
- @end table
- In the future, new items may be added to the end of the default formatting
- strings. Users who depend on the format staying exactly the same, should
- prescribe it manually.
- Note that stats for different streams written into the same file may have
- different formats.
- @end table
- @section Preset files
- A preset file contains a sequence of @var{option}=@var{value} pairs,
- one for each line, specifying a sequence of options which would be
- awkward to specify on the command line. Lines starting with the hash
- ('#') character are ignored and are used to provide comments. Check
- the @file{presets} directory in the FFmpeg source tree for examples.
- There are two types of preset files: ffpreset and avpreset files.
- @subsection ffpreset files
- ffpreset files are specified with the @code{vpre}, @code{apre},
- @code{spre}, and @code{fpre} options. The @code{fpre} option takes the
- filename of the preset instead of a preset name as input and can be
- used for any kind of codec. For the @code{vpre}, @code{apre}, and
- @code{spre} options, the options specified in a preset file are
- applied to the currently selected codec of the same type as the preset
- option.
- The argument passed to the @code{vpre}, @code{apre}, and @code{spre}
- preset options identifies the preset file to use according to the
- following rules:
- First ffmpeg searches for a file named @var{arg}.ffpreset in the
- directories @file{$FFMPEG_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
- the datadir defined at configuration time (usually @file{PREFIX/share/ffmpeg})
- or in a @file{ffpresets} folder along the executable on win32,
- in that order. For example, if the argument is @code{libvpx-1080p}, it will
- search for the file @file{libvpx-1080p.ffpreset}.
- If no such file is found, then ffmpeg will search for a file named
- @var{codec_name}-@var{arg}.ffpreset in the above-mentioned
- directories, where @var{codec_name} is the name of the codec to which
- the preset file options will be applied. For example, if you select
- the video codec with @code{-vcodec libvpx} and use @code{-vpre 1080p},
- then it will search for the file @file{libvpx-1080p.ffpreset}.
- @subsection avpreset files
- avpreset files are specified with the @code{pre} option. They work similar to
- ffpreset files, but they only allow encoder- specific options. Therefore, an
- @var{option}=@var{value} pair specifying an encoder cannot be used.
- When the @code{pre} option is specified, ffmpeg will look for files with the
- suffix .avpreset in the directories @file{$AVCONV_DATADIR} (if set), and
- @file{$HOME/.avconv}, and in the datadir defined at configuration time (usually
- @file{PREFIX/share/ffmpeg}), in that order.
- First ffmpeg searches for a file named @var{codec_name}-@var{arg}.avpreset in
- the above-mentioned directories, where @var{codec_name} is the name of the codec
- to which the preset file options will be applied. For example, if you select the
- video codec with @code{-vcodec libvpx} and use @code{-pre 1080p}, then it will
- search for the file @file{libvpx-1080p.avpreset}.
- If no such file is found, then ffmpeg will search for a file named
- @var{arg}.avpreset in the same directories.
- @anchor{vstats_file_format}
- @section vstats file format
- The @code{-vstats} and @code{-vstats_file} options enable generation of a file
- containing statistics about the generated video outputs.
- The @code{-vstats_version} option controls the format version of the generated
- file.
- With version @code{1} the format is:
- @example
- frame= @var{FRAME} q= @var{FRAME_QUALITY} PSNR= @var{PSNR} f_size= @var{FRAME_SIZE} s_size= @var{STREAM_SIZE}kB time= @var{TIMESTAMP} br= @var{BITRATE}kbits/s avg_br= @var{AVERAGE_BITRATE}kbits/s
- @end example
- With version @code{2} the format is:
- @example
- out= @var{OUT_FILE_INDEX} st= @var{OUT_FILE_STREAM_INDEX} frame= @var{FRAME_NUMBER} q= @var{FRAME_QUALITY}f PSNR= @var{PSNR} f_size= @var{FRAME_SIZE} s_size= @var{STREAM_SIZE}kB time= @var{TIMESTAMP} br= @var{BITRATE}kbits/s avg_br= @var{AVERAGE_BITRATE}kbits/s
- @end example
- The value corresponding to each key is described below:
- @table @option
- @item avg_br
- average bitrate expressed in Kbits/s
- @item br
- bitrate expressed in Kbits/s
- @item frame
- number of encoded frame
- @item out
- out file index
- @item PSNR
- Peak Signal to Noise Ratio
- @item q
- quality of the frame
- @item f_size
- encoded packet size expressed as number of bytes
- @item s_size
- stream size expressed in KiB
- @item st
- out file stream index
- @item time
- time of the packet
- @item type
- picture type
- @end table
- See also the @ref{stats_enc_options,,-stats_enc options} for an alternative way
- to show encoding statistics.
- @c man end OPTIONS
- @chapter Examples
- @c man begin EXAMPLES
- @section Video and Audio grabbing
- If you specify the input format and device then ffmpeg can grab video
- and audio directly.
- @example
- ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
- @end example
- Or with an ALSA audio source (mono input, card id 1) instead of OSS:
- @example
- ffmpeg -f alsa -ac 1 -i hw:1 -f video4linux2 -i /dev/video0 /tmp/out.mpg
- @end example
- Note that you must activate the right video source and channel before
- launching ffmpeg with any TV viewer such as
- @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also
- have to set the audio recording levels correctly with a
- standard mixer.
- @section X11 grabbing
- Grab the X11 display with ffmpeg via
- @example
- ffmpeg -f x11grab -video_size cif -framerate 25 -i :0.0 /tmp/out.mpg
- @end example
- 0.0 is display.screen number of your X11 server, same as
- the DISPLAY environment variable.
- @example
- ffmpeg -f x11grab -video_size cif -framerate 25 -i :0.0+10,20 /tmp/out.mpg
- @end example
- 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
- variable. 10 is the x-offset and 20 the y-offset for the grabbing.
- @section Video and Audio file format conversion
- Any supported file format and protocol can serve as input to ffmpeg:
- Examples:
- @itemize
- @item
- You can use YUV files as input:
- @example
- ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
- @end example
- It will use the files:
- @example
- /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
- /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
- @end example
- The Y files use twice the resolution of the U and V files. They are
- raw files, without header. They can be generated by all decent video
- decoders. You must specify the size of the image with the @option{-s} option
- if ffmpeg cannot guess it.
- @item
- You can input from a raw YUV420P file:
- @example
- ffmpeg -i /tmp/test.yuv /tmp/out.avi
- @end example
- test.yuv is a file containing raw YUV planar data. Each frame is composed
- of the Y plane followed by the U and V planes at half vertical and
- horizontal resolution.
- @item
- You can output to a raw YUV420P file:
- @example
- ffmpeg -i mydivx.avi hugefile.yuv
- @end example
- @item
- You can set several input files and output files:
- @example
- ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
- @end example
- Converts the audio file a.wav and the raw YUV video file a.yuv
- to MPEG file a.mpg.
- @item
- You can also do audio and video conversions at the same time:
- @example
- ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
- @end example
- Converts a.wav to MPEG audio at 22050 Hz sample rate.
- @item
- You can encode to several formats at the same time and define a
- mapping from input stream to output streams:
- @example
- ffmpeg -i /tmp/a.wav -map 0:a -b:a 64k /tmp/a.mp2 -map 0:a -b:a 128k /tmp/b.mp2
- @end example
- Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
- file:index' specifies which input stream is used for each output
- stream, in the order of the definition of output streams.
- @item
- You can transcode decrypted VOBs:
- @example
- ffmpeg -i snatch_1.vob -f avi -c:v mpeg4 -b:v 800k -g 300 -bf 2 -c:a libmp3lame -b:a 128k snatch.avi
- @end example
- This is a typical DVD ripping example; the input is a VOB file, the
- output an AVI file with MPEG-4 video and MP3 audio. Note that in this
- command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
- GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
- input video. Furthermore, the audio stream is MP3-encoded so you need
- to enable LAME support by passing @code{--enable-libmp3lame} to configure.
- The mapping is particularly useful for DVD transcoding
- to get the desired audio language.
- NOTE: To see the supported input formats, use @code{ffmpeg -demuxers}.
- @item
- You can extract images from a video, or create a video from many images:
- For extracting images from a video:
- @example
- ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
- @end example
- This will extract one video frame per second from the video and will
- output them in files named @file{foo-001.jpeg}, @file{foo-002.jpeg},
- etc. Images will be rescaled to fit the new WxH values.
- If you want to extract just a limited number of frames, you can use the
- above command in combination with the @code{-frames:v} or @code{-t} option,
- or in combination with -ss to start extracting from a certain point in time.
- For creating a video from many images:
- @example
- ffmpeg -f image2 -framerate 12 -i foo-%03d.jpeg -s WxH foo.avi
- @end example
- The syntax @code{foo-%03d.jpeg} specifies to use a decimal number
- composed of three digits padded with zeroes to express the sequence
- number. It is the same syntax supported by the C printf function, but
- only formats accepting a normal integer are suitable.
- When importing an image sequence, -i also supports expanding
- shell-like wildcard patterns (globbing) internally, by selecting the
- image2-specific @code{-pattern_type glob} option.
- For example, for creating a video from filenames matching the glob pattern
- @code{foo-*.jpeg}:
- @example
- ffmpeg -f image2 -pattern_type glob -framerate 12 -i 'foo-*.jpeg' -s WxH foo.avi
- @end example
- @item
- You can put many streams of the same type in the output:
- @example
- ffmpeg -i test1.avi -i test2.avi -map 1:1 -map 1:0 -map 0:1 -map 0:0 -c copy -y test12.nut
- @end example
- The resulting output file @file{test12.nut} will contain the first four streams
- from the input files in reverse order.
- @item
- To force CBR video output:
- @example
- ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
- @end example
- @item
- The four options lmin, lmax, mblmin and mblmax use 'lambda' units,
- but you may use the QP2LAMBDA constant to easily convert from 'q' units:
- @example
- ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
- @end example
- @end itemize
- @c man end EXAMPLES
- @include config.texi
- @ifset config-all
- @ifset config-avutil
- @include utils.texi
- @end ifset
- @ifset config-avcodec
- @include codecs.texi
- @include bitstream_filters.texi
- @end ifset
- @ifset config-avformat
- @include formats.texi
- @include protocols.texi
- @end ifset
- @ifset config-avdevice
- @include devices.texi
- @end ifset
- @ifset config-swresample
- @include resampler.texi
- @end ifset
- @ifset config-swscale
- @include scaler.texi
- @end ifset
- @ifset config-avfilter
- @include filters.texi
- @end ifset
- @include general_contents.texi
- @end ifset
- @chapter See Also
- @ifhtml
- @ifset config-all
- @url{ffmpeg.html,ffmpeg}
- @end ifset
- @ifset config-not-all
- @url{ffmpeg-all.html,ffmpeg-all},
- @end ifset
- @url{ffplay.html,ffplay}, @url{ffprobe.html,ffprobe},
- @url{ffmpeg-utils.html,ffmpeg-utils},
- @url{ffmpeg-scaler.html,ffmpeg-scaler},
- @url{ffmpeg-resampler.html,ffmpeg-resampler},
- @url{ffmpeg-codecs.html,ffmpeg-codecs},
- @url{ffmpeg-bitstream-filters.html,ffmpeg-bitstream-filters},
- @url{ffmpeg-formats.html,ffmpeg-formats},
- @url{ffmpeg-devices.html,ffmpeg-devices},
- @url{ffmpeg-protocols.html,ffmpeg-protocols},
- @url{ffmpeg-filters.html,ffmpeg-filters}
- @end ifhtml
- @ifnothtml
- @ifset config-all
- ffmpeg(1),
- @end ifset
- @ifset config-not-all
- ffmpeg-all(1),
- @end ifset
- ffplay(1), ffprobe(1),
- ffmpeg-utils(1), ffmpeg-scaler(1), ffmpeg-resampler(1),
- ffmpeg-codecs(1), ffmpeg-bitstream-filters(1), ffmpeg-formats(1),
- ffmpeg-devices(1), ffmpeg-protocols(1), ffmpeg-filters(1)
- @end ifnothtml
- @include authors.texi
- @ignore
- @setfilename ffmpeg
- @settitle ffmpeg media converter
- @end ignore
- @bye
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