18f43de964
Also extends documentation for timestamp related ffmpeg options, in order to make more apparent the fact that muxer processing may change the timestamps values.
1386 lines
53 KiB
Plaintext
1386 lines
53 KiB
Plaintext
\input texinfo @c -*- texinfo -*-
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@settitle ffmpeg Documentation
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@titlepage
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@center @titlefont{ffmpeg Documentation}
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@end titlepage
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@top
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@contents
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@chapter Synopsis
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ffmpeg [@var{global_options}] @{[@var{input_file_options}] -i @file{input_file}@} ... @{[@var{output_file_options}] @file{output_file}@} ...
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@chapter Description
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@c man begin DESCRIPTION
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ffmpeg is a very fast video and audio converter that can also grab from
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a live audio/video source. It can also convert between arbitrary sample
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rates and resize video on the fly with a high quality polyphase filter.
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ffmpeg reads from an arbitrary number of input "files" (which can be regular
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files, pipes, network streams, grabbing devices, etc.), specified by the
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@code{-i} option, and writes to an arbitrary number of output "files", which are
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specified by a plain output filename. Anything found on the command line which
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cannot be interpreted as an option is considered to be an output filename.
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Each input or output file can in principle contain any number of streams of
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different types (video/audio/subtitle/attachment/data). Allowed number and/or
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types of streams can be limited by the container format. Selecting, which
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streams from which inputs go into output, is done either automatically or with
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the @code{-map} option (see the Stream selection chapter).
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To refer to input files in options, you must use their indices (0-based). E.g.
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the first input file is @code{0}, the second is @code{1} etc. Similarly, streams
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within a file are referred to by their indices. E.g. @code{2:3} refers to the
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fourth stream in the third input file. See also the Stream specifiers chapter.
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As a general rule, options are applied to the next specified
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file. Therefore, order is important, and you can have the same
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option on the command line multiple times. Each occurrence is
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then applied to the next input or output file.
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Exceptions from this rule are the global options (e.g. verbosity level),
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which should be specified first.
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Do not mix input and output files -- first specify all input files, then all
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output files. Also do not mix options which belong to different files. All
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options apply ONLY to the next input or output file and are reset between files.
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@itemize
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@item
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To set the video bitrate of the output file to 64kbit/s:
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@example
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ffmpeg -i input.avi -b:v 64k -bufsize 64k output.avi
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@end example
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@item
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To force the frame rate of the output file to 24 fps:
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@example
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ffmpeg -i input.avi -r 24 output.avi
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@end example
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@item
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To force the frame rate of the input file (valid for raw formats only)
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to 1 fps and the frame rate of the output file to 24 fps:
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@example
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ffmpeg -r 1 -i input.m2v -r 24 output.avi
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@end example
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@end itemize
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The format option may be needed for raw input files.
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@c man end DESCRIPTION
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@chapter Detailed description
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@c man begin DETAILED DESCRIPTION
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The transcoding process in @command{ffmpeg} for each output can be described by
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the following diagram:
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@example
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_______ ______________ _________ ______________ ________
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| | | | | | | | | |
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| input | demuxer | encoded data | decoder | decoded | encoder | encoded data | muxer | output |
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| file | ---------> | packets | ---------> | frames | ---------> | packets | -------> | file |
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|_______| |______________| |_________| |______________| |________|
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@end example
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@command{ffmpeg} calls the libavformat library (containing demuxers) to read
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input files and get packets containing encoded data from them. When there are
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multiple input files, @command{ffmpeg} tries to keep them synchronized by
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tracking lowest timestamp on any active input stream.
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Encoded packets are then passed to the decoder (unless streamcopy is selected
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for the stream, see further for a description). The decoder produces
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uncompressed frames (raw video/PCM audio/...) which can be processed further by
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filtering (see next section). After filtering the frames are passed to the
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encoder, which encodes them and outputs encoded packets again. Finally those are
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passed to the muxer, which writes the encoded packets to the output file.
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@section Filtering
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Before encoding, @command{ffmpeg} can process raw audio and video frames using
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filters from the libavfilter library. Several chained filters form a filter
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graph. @command{ffmpeg} distinguishes between two types of filtergraphs -
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simple and complex.
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@subsection Simple filtergraphs
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Simple filtergraphs are those that have exactly one input and output, both of
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the same type. In the above diagram they can be represented by simply inserting
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an additional step between decoding and encoding:
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@example
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_________ __________ ______________
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| | | | | |
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| decoded | simple filtergraph | filtered | encoder | encoded data |
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| frames | -------------------> | frames | ---------> | packets |
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|_________| |__________| |______________|
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@end example
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Simple filtergraphs are configured with the per-stream @option{-filter} option
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(with @option{-vf} and @option{-af} aliases for video and audio respectively).
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A simple filtergraph for video can look for example like this:
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@example
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_______ _____________ _______ _____ ________
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| | | | | | | | | |
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| input | ---> | deinterlace | ---> | scale | ---> | fps | ---> | output |
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|_______| |_____________| |_______| |_____| |________|
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@end example
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Note that some filters change frame properties but not frame contents. E.g. the
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@code{fps} filter in the example above changes number of frames, but does not
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touch the frame contents. Another example is the @code{setpts} filter, which
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only sets timestamps and otherwise passes the frames unchanged.
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@subsection Complex filtergraphs
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Complex filtergraphs are those which cannot be described as simply a linear
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processing chain applied to one stream. This is the case e.g. when the graph has
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more than one input and/or output, or when output stream type is different from
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input. They can be represented with the following diagram:
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@example
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_________
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| |
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| input 0 |\ __________
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|_________| \ | |
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\ _________ /| output 0 |
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\ | | / |__________|
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_________ \| complex | /
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| | | |/
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| input 1 |---->| filter |\
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|_________| | | \ __________
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/| graph | \ | |
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/ | | \| output 1 |
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_________ / |_________| |__________|
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| | /
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| input 2 |/
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|_________|
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@end example
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Complex filtergraphs are configured with the @option{-filter_complex} option.
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Note that this option is global, since a complex filtergraph by its nature
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cannot be unambiguously associated with a single stream or file.
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The @option{-lavfi} option is equivalent to @option{-filter_complex}.
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A trivial example of a complex filtergraph is the @code{overlay} filter, which
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has two video inputs and one video output, containing one video overlaid on top
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of the other. Its audio counterpart is the @code{amix} filter.
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@section Stream copy
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Stream copy is a mode selected by supplying the @code{copy} parameter to the
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@option{-codec} option. It makes @command{ffmpeg} omit the decoding and encoding
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step for the specified stream, so it does only demuxing and muxing. It is useful
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for changing the container format or modifying container-level metadata. The
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diagram above will in this case simplify to this:
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@example
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_______ ______________ ________
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| input | demuxer | encoded data | muxer | output |
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| file | ---------> | packets | -------> | file |
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|_______| |______________| |________|
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@end example
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Since there is no decoding or encoding, it is very fast and there is no quality
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loss. However it might not work in some cases because of many factors. Applying
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filters is obviously also impossible, since filters work on uncompressed data.
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@c man end DETAILED DESCRIPTION
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@chapter Stream selection
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@c man begin STREAM SELECTION
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By default ffmpeg includes only one stream of each type (video, audio, subtitle)
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present in the input files and adds them to each output file. It picks the
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"best" of each based upon the following criteria; for video it is the stream
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with the highest resolution, for audio the stream with the most channels, for
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subtitle it's the first subtitle stream. In the case where several streams of
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the same type rate equally, the lowest numbered stream is chosen.
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You can disable some of those defaults by using @code{-vn/-an/-sn} options. For
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full manual control, use the @code{-map} option, which disables the defaults just
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described.
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@c man end STREAM SELECTION
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@chapter Options
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@c man begin OPTIONS
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@include avtools-common-opts.texi
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@section Main options
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@table @option
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@item -f @var{fmt} (@emph{input/output})
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Force input or output file format. The format is normally auto detected for input
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files and guessed from file extension for output files, so this option is not
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needed in most cases.
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@item -i @var{filename} (@emph{input})
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input file name
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@item -y (@emph{global})
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Overwrite output files without asking.
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@item -n (@emph{global})
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Do not overwrite output files but exit if file exists.
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@item -c[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
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@itemx -codec[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream})
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Select an encoder (when used before an output file) or a decoder (when used
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before an input file) for one or more streams. @var{codec} is the name of a
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decoder/encoder or a special value @code{copy} (output only) to indicate that
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the stream is not to be re-encoded.
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For example
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@example
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ffmpeg -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
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@end example
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encodes all video streams with libx264 and copies all audio streams.
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For each stream, the last matching @code{c} option is applied, so
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@example
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ffmpeg -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
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@end example
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will copy all the streams except the second video, which will be encoded with
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libx264, and the 138th audio, which will be encoded with libvorbis.
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@item -t @var{duration} (@emph{output})
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Stop writing the output after its duration reaches @var{duration}.
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@var{duration} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.
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-to and -t are mutually exclusive and -t has priority.
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@item -to @var{position} (@emph{output})
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Stop writing the output at @var{position}.
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@var{position} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form.
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-to and -t are mutually exclusive and -t has priority.
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@item -fs @var{limit_size} (@emph{output})
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Set the file size limit, expressed in bytes.
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@item -ss @var{position} (@emph{input/output})
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When used as an input option (before @code{-i}), seeks in this input file to
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@var{position}. When used as an output option (before an output filename),
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decodes but discards input until the timestamps reach @var{position}. This is
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slower, but more accurate.
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@var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form.
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@item -itsoffset @var{offset} (@emph{input})
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Set the input time offset in seconds.
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@code{[-]hh:mm:ss[.xxx]} syntax is also supported.
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The offset is added to the timestamps of the input files.
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Specifying a positive offset means that the corresponding
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streams are delayed by @var{offset} seconds.
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@item -timestamp @var{time} (@emph{output})
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Set the recording timestamp in the container.
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The syntax for @var{time} is:
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@example
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now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH:MM:SS[.m...])|(HHMMSS[.m...]))[Z|z])
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@end example
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If the value is "now" it takes the current time.
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Time is local time unless 'Z' or 'z' is appended, in which case it is
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interpreted as UTC.
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If the year-month-day part is not specified it takes the current
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year-month-day.
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@item -metadata[:metadata_specifier] @var{key}=@var{value} (@emph{output,per-metadata})
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Set a metadata key/value pair.
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An optional @var{metadata_specifier} may be given to set metadata
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on streams or chapters. See @code{-map_metadata} documentation for
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details.
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This option overrides metadata set with @code{-map_metadata}. It is
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also possible to delete metadata by using an empty value.
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For example, for setting the title in the output file:
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@example
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ffmpeg -i in.avi -metadata title="my title" out.flv
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@end example
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To set the language of the first audio stream:
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@example
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ffmpeg -i INPUT -metadata:s:a:1 language=eng OUTPUT
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@end example
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@item -target @var{type} (@emph{output})
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Specify target file type (@code{vcd}, @code{svcd}, @code{dvd}, @code{dv},
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@code{dv50}). @var{type} may be prefixed with @code{pal-}, @code{ntsc-} or
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@code{film-} to use the corresponding standard. All the format options
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(bitrate, codecs, buffer sizes) are then set automatically. You can just type:
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@example
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ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
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@end example
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Nevertheless you can specify additional options as long as you know
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they do not conflict with the standard, as in:
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@example
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ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
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@end example
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@item -dframes @var{number} (@emph{output})
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Set the number of data frames to record. This is an alias for @code{-frames:d}.
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@item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream})
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Stop writing to the stream after @var{framecount} frames.
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@item -q[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
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@itemx -qscale[:@var{stream_specifier}] @var{q} (@emph{output,per-stream})
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Use fixed quality scale (VBR). The meaning of @var{q} is
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codec-dependent.
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@anchor{filter_option}
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@item -filter[:@var{stream_specifier}] @var{filter_graph} (@emph{output,per-stream})
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Create the filter graph specified by @var{filter_graph} and use it to
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filter the stream.
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@var{filter_graph} is a description of the filter graph to apply to
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the stream, and must have a single input and a single output of the
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same type of the stream. In the filter graph, the input is associated
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to the label @code{in}, and the output to the label @code{out}. See
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the ffmpeg-filters manual for more information about the filtergraph
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syntax.
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See the @ref{filter_complex_option,,-filter_complex option} if you
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want to create filter graphs with multiple inputs and/or outputs.
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@item -pre[:@var{stream_specifier}] @var{preset_name} (@emph{output,per-stream})
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Specify the preset for matching stream(s).
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@item -stats (@emph{global})
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Print encoding progress/statistics. It is on by default, to explicitly
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disable it you need to specify @code{-nostats}.
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@item -progress @var{url} (@emph{global})
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Send program-friendly progress information to @var{url}.
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Progress information is written approximately every second and at the end of
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the encoding process. It is made of "@var{key}=@var{value}" lines. @var{key}
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consists of only alphanumeric characters. The last key of a sequence of
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progress information is always "progress".
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@item -stdin
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Enable interaction on standard input. On by default unless standard input is
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used as an input. To explicitly disable interaction you need to specify
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@code{-nostdin}.
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Disabling interaction on standard input is useful, for example, if
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ffmpeg is in the background process group. Roughly the same result can
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be achieved with @code{ffmpeg ... < /dev/null} but it requires a
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shell.
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@item -debug_ts (@emph{global})
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Print timestamp information. It is off by default. This option is
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mostly useful for testing and debugging purposes, and the output
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format may change from one version to another, so it should not be
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employed by portable scripts.
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See also the option @code{-fdebug ts}.
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@item -attach @var{filename} (@emph{output})
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Add an attachment to the output file. This is supported by a few formats
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like Matroska for e.g. fonts used in rendering subtitles. Attachments
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are implemented as a specific type of stream, so this option will add
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a new stream to the file. It is then possible to use per-stream options
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on this stream in the usual way. Attachment streams created with this
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option will be created after all the other streams (i.e. those created
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with @code{-map} or automatic mappings).
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Note that for Matroska you also have to set the mimetype metadata tag:
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@example
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ffmpeg -i INPUT -attach DejaVuSans.ttf -metadata:s:2 mimetype=application/x-truetype-font out.mkv
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@end example
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(assuming that the attachment stream will be third in the output file).
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@item -dump_attachment[:@var{stream_specifier}] @var{filename} (@emph{input,per-stream})
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Extract the matching attachment stream into a file named @var{filename}. If
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@var{filename} is empty, then the value of the @code{filename} metadata tag
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will be used.
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E.g. to extract the first attachment to a file named 'out.ttf':
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@example
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ffmpeg -dump_attachment:t:0 out.ttf -i INPUT
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@end example
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To extract all attachments to files determined by the @code{filename} tag:
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@example
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ffmpeg -dump_attachment:t "" -i INPUT
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@end example
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Technical note -- attachments are implemented as codec extradata, so this
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option can actually be used to extract extradata from any stream, not just
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attachments.
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@end table
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@section Video Options
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@table @option
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@item -vframes @var{number} (@emph{output})
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Set the number of video frames to record. This is an alias for @code{-frames:v}.
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@item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream})
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Set frame rate (Hz value, fraction or abbreviation).
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As an input option, ignore any timestamps stored in the file and instead
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generate timestamps assuming constant frame rate @var{fps}.
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As an output option, duplicate or drop input frames to achieve constant output
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frame rate @var{fps}.
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@item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream})
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Set frame size.
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As an input option, this is a shortcut for the @option{video_size} private
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option, recognized by some demuxers for which the frame size is either not
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stored in the file or is configurable -- e.g. raw video or video grabbers.
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As an output option, this inserts the @code{scale} video filter to the
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@emph{end} of the corresponding filtergraph. Please use the @code{scale} filter
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directly to insert it at the beginning or some other place.
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The format is @samp{wxh} (default - same as source).
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@item -aspect[:@var{stream_specifier}] @var{aspect} (@emph{output,per-stream})
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Set the video display aspect ratio specified by @var{aspect}.
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@var{aspect} can be a floating point number string, or a string of the
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form @var{num}:@var{den}, where @var{num} and @var{den} are the
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numerator and denominator of the aspect ratio. For example "4:3",
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|
"16:9", "1.3333", and "1.7777" are valid argument values.
|
|
|
|
@item -vn (@emph{output})
|
|
Disable video recording.
|
|
|
|
@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 -vlang @var{code}
|
|
Set the ISO 639 language code (3 letters) of the current video stream.
|
|
|
|
@item -vf @var{filter_graph} (@emph{output})
|
|
Create the filter graph specified by @var{filter_graph} and use it to
|
|
filter the stream.
|
|
|
|
This is an alias for @code{-filter:v}, see the @ref{filter_option,,-filter option}.
|
|
@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 filter graphs 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 SwScaler flags.
|
|
@item -vdt @var{n}
|
|
Discard threshold.
|
|
|
|
@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 -deinterlace
|
|
Deinterlace pictures.
|
|
This option is deprecated since the deinterlacing is very low quality.
|
|
Use the yadif filter with @code{-filter:v yadif}.
|
|
@item -ilme
|
|
Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
|
|
Use this option if your input file is interlaced and you want
|
|
to keep the interlaced format for minimum losses.
|
|
The alternative is to deinterlace the input stream with
|
|
@option{-deinterlace}, but deinterlacing introduces losses.
|
|
@item -psnr
|
|
Calculate PSNR of compressed frames.
|
|
@item -vstats
|
|
Dump video coding statistics to @file{vstats_HHMMSS.log}.
|
|
@item -vstats_file @var{file}
|
|
Dump video coding statistics to @var{file}.
|
|
@item -top[:@var{stream_specifier}] @var{n} (@emph{output,per-stream})
|
|
top=1/bottom=0/auto=-1 field first
|
|
@item -dc @var{precision}
|
|
Intra_dc_precision.
|
|
@item -vtag @var{fourcc/tag} (@emph{output})
|
|
Force video tag/fourcc. This is an alias for @code{-tag:v}.
|
|
@item -qphist (@emph{global})
|
|
Show QP histogram
|
|
@item -vbsf @var{bitstream_filter}
|
|
Deprecated see -bsf
|
|
|
|
@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})
|
|
Force key frames at the specified timestamps, more precisely at the first
|
|
frames after each specified time.
|
|
|
|
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.
|
|
|
|
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
|
|
|
|
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
|
|
|
|
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.
|
|
@end table
|
|
|
|
@section Audio Options
|
|
|
|
@table @option
|
|
@item -aframes @var{number} (@emph{output})
|
|
Set the number of audio frames to record. This is an alias for @code{-frames:a}.
|
|
@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{output})
|
|
Disable audio recording.
|
|
@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{filter_graph} (@emph{output})
|
|
Create the filter graph specified by @var{filter_graph} 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 -absf @var{bitstream_filter}
|
|
Deprecated, see -bsf
|
|
@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.
|
|
@end table
|
|
|
|
@section Subtitle options:
|
|
|
|
@table @option
|
|
@item -slang @var{code}
|
|
Set the ISO 639 language code (3 letters) of the current subtitle stream.
|
|
@item -scodec @var{codec} (@emph{input/output})
|
|
Set the subtitle codec. This is an alias for @code{-codec:s}.
|
|
@item -sn (@emph{output})
|
|
Disable subtitle recording.
|
|
@item -sbsf @var{bitstream_filter}
|
|
Deprecated, see -bsf
|
|
@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{sync_file_id}[:@var{stream_specifier}]] | @var{[linklabel]} (@emph{output})
|
|
|
|
Designate one or more input streams as a source for the output file. Each input
|
|
stream is identified by the input file index @var{input_file_id} and
|
|
the input stream index @var{input_stream_id} within the input
|
|
file. Both indices start at 0. If specified,
|
|
@var{sync_file_id}:@var{stream_specifier} sets which input stream
|
|
is used as a presentation sync reference.
|
|
|
|
The first @code{-map} option on the command line specifies the
|
|
source for output stream 0, the second @code{-map} option specifies
|
|
the source for output stream 1, etc.
|
|
|
|
A @code{-} character before the stream identifier creates a "negative" mapping.
|
|
It disables matching streams from already created mappings.
|
|
|
|
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.
|
|
|
|
For example, to map ALL streams from the first input file to output
|
|
@example
|
|
ffmpeg -i INPUT -map 0 output
|
|
@end example
|
|
|
|
For example, if you have two audio streams in the first input file,
|
|
these streams are identified by "0:0" and "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 input stream in @file{INPUT} identified by "0:1" to
|
|
the (single) output stream in @file{out.wav}.
|
|
|
|
For example, to select the stream with index 2 from input file
|
|
@file{a.mov} (specified by the identifier "0:2"), and stream with
|
|
index 6 from input @file{b.mov} (specified by the identifier "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
|
|
|
|
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
|
|
|
|
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
|
|
|
|
Note that using this option disables the default mappings for this output file.
|
|
|
|
@item -map_channel [@var{input_file_id}.@var{stream_specifier}.@var{channel_id}|-1][:@var{output_file_id}.@var{stream_specifier}]
|
|
Map an audio channel from a given input to an output. If
|
|
@var{output_file_id}.@var{stream_specifier} is not set, the audio channel will
|
|
be mapped on all the audio streams.
|
|
|
|
Using "-1" instead of
|
|
@var{input_file_id}.@var{stream_specifier}.@var{channel_id} will map a muted
|
|
channel.
|
|
|
|
For example, assuming @var{INPUT} is a stereo audio file, you can switch the
|
|
two audio channels with the following command:
|
|
@example
|
|
ffmpeg -i INPUT -map_channel 0.0.1 -map_channel 0.0.0 OUTPUT
|
|
@end example
|
|
|
|
If you want to mute the first channel and keep the second:
|
|
@example
|
|
ffmpeg -i INPUT -map_channel -1 -map_channel 0.0.1 OUTPUT
|
|
@end example
|
|
|
|
The order of the "-map_channel" option specifies the order of the channels in
|
|
the output stream. The output channel layout is guessed from the number of
|
|
channels mapped (mono if one "-map_channel", stereo if two, etc.). Using "-ac"
|
|
in combination of "-map_channel" makes the channel gain levels to be updated if
|
|
input and output channel layouts don't match (for instance two "-map_channel"
|
|
options and "-ac 6").
|
|
|
|
You can also extract each channel of an input to specific outputs; the following
|
|
command extracts two channels of the @var{INPUT} audio stream (file 0, stream 0)
|
|
to the respective @var{OUTPUT_CH0} and @var{OUTPUT_CH1} outputs:
|
|
@example
|
|
ffmpeg -i INPUT -map_channel 0.0.0 OUTPUT_CH0 -map_channel 0.0.1 OUTPUT_CH1
|
|
@end example
|
|
|
|
The following example splits the channels of a stereo input into two separate
|
|
streams, which are put into the same output file:
|
|
@example
|
|
ffmpeg -i stereo.wav -map 0:0 -map 0:0 -map_channel 0.0.0:0.0 -map_channel 0.0.1:0.1 -y out.ogg
|
|
@end example
|
|
|
|
Note that currently each output stream can only contain channels from a single
|
|
input stream; you can't for example use "-map_channel" to pick multiple input
|
|
audio channels contained in different streams (from the same or different files)
|
|
and merge them into a single output stream. It is therefore not currently
|
|
possible, for example, to turn two separate mono streams into a single stereo
|
|
stream. However splitting a stereo stream into two single channel mono streams
|
|
is possible.
|
|
|
|
If you need this feature, a possible workaround is to use the @emph{amerge}
|
|
filter. For example, if you need to merge a media (here @file{input.mkv}) with 2
|
|
mono audio streams into one single stereo channel audio stream (and keep the
|
|
video stream), you can use the following command:
|
|
@example
|
|
ffmpeg -i input.mkv -filter_complex "[0:1] [0:2] amerge" -c:a pcm_s16le -c:v copy output.mkv
|
|
@end example
|
|
|
|
@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 CPU 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 CPU 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.
|
|
@item -dump (@emph{global})
|
|
Dump each input packet to stderr.
|
|
@item -hex (@emph{global})
|
|
When dumping packets, also dump the payload.
|
|
@item -re (@emph{input})
|
|
Read input at native frame rate. Mainly used to simulate a grab device.
|
|
By default @command{ffmpeg} attempts to read the input(s) as fast as possible.
|
|
This option will slow down the reading of the input(s) to the native frame rate
|
|
of the input(s). It is useful for real-time output (e.g. live streaming). If
|
|
your input(s) is coming from some other live streaming source (through HTTP or
|
|
UDP for example) the server might already be in real-time, thus the option will
|
|
likely not be required. On the other hand, this is meaningful if your input(s)
|
|
is a file you are trying to push in real-time.
|
|
@item -loop_input
|
|
Loop over the input stream. Currently it works only for image
|
|
streams. This option is used for automatic FFserver testing.
|
|
This option is deprecated, use -loop 1.
|
|
@item -loop_output @var{number_of_times}
|
|
Repeatedly loop output for formats that support looping such as animated GIF
|
|
(0 will loop the output infinitely).
|
|
This option is deprecated, use -loop.
|
|
@item -vsync @var{parameter}
|
|
Video sync method.
|
|
For compatibility reasons old values can be specified as numbers.
|
|
Newly added values will have to be specified as strings always.
|
|
|
|
@table @option
|
|
@item 0, passthrough
|
|
Each frame is passed with its timestamp from the demuxer to the muxer.
|
|
@item 1, cfr
|
|
Frames will be duplicated and dropped to achieve exactly the requested
|
|
constant framerate.
|
|
@item 2, vfr
|
|
Frames are passed through with their timestamp or dropped so as to
|
|
prevent 2 frames from having the same timestamp.
|
|
@item drop
|
|
As passthrough but destroys all timestamps, making the muxer generate
|
|
fresh timestamps based on frame-rate.
|
|
@item -1, auto
|
|
Chooses between 1 and 2 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 -async @var{samples_per_second}
|
|
Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
|
|
the parameter is the maximum samples per second by which the audio is changed.
|
|
-async 1 is a special case where only the start of the audio stream is corrected
|
|
without any later correction.
|
|
|
|
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.
|
|
|
|
This option has been deprecated. Use the @code{aresample} audio filter instead.
|
|
|
|
@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 -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 -shortest (@emph{output})
|
|
Finish encoding when the shortest input stream ends.
|
|
@item -dts_delta_threshold
|
|
Timestamp discontinuity delta threshold.
|
|
@item -muxdelay @var{seconds} (@emph{input})
|
|
Set the maximum demux-decode delay.
|
|
@item -muxpreload @var{seconds} (@emph{input})
|
|
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 infile -streamid 0:33 -streamid 1:36 out.ts
|
|
@end example
|
|
|
|
@item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{output,per-stream})
|
|
Set bitstream filters for matching streams. @var{bitstream_filters} is
|
|
a comma-separated list of bitstream filters. Use the @code{-bsfs} option
|
|
to get the list of bitstream filters.
|
|
@example
|
|
ffmpeg -i h264.mp4 -c:v copy -bsf:v h264_mp4toannexb -an out.h264
|
|
@end example
|
|
@example
|
|
ffmpeg -i file.mov -an -vn -bsf:s mov2textsub -c:s copy -f rawvideo sub.txt
|
|
@end example
|
|
|
|
@item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{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 filter graph, 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 filter graph, as described in the ``Filtergraph syntax'' section of the
|
|
ffmpeg-filters manual.
|
|
|
|
Input link labels must refer to input streams using the
|
|
@code{[file_index:stream_specifier]} syntax (i.e. the same as @option{-map}
|
|
uses). If @var{stream_specifier} matches multiple streams, the first one will be
|
|
used. 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
|
|
|
|
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 -lavfi @var{filtergraph} (@emph{global})
|
|
Define a complex filter graph, i.e. one with arbitrary number of inputs and/or
|
|
outputs. Equivalent to @option{-filter_complex}.
|
|
|
|
@end table
|
|
|
|
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)
|
|
|
|
@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.
|
|
|
|
Preset 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}.
|
|
@c man end OPTIONS
|
|
|
|
@chapter Tips
|
|
@c man begin TIPS
|
|
|
|
@itemize
|
|
@item
|
|
For streaming at very low bitrate application, use a low frame rate
|
|
and a small GOP size. This is especially true for RealVideo where
|
|
the Linux player does not seem to be very fast, so it can miss
|
|
frames. An example is:
|
|
|
|
@example
|
|
ffmpeg -g 3 -r 3 -t 10 -b:v 50k -s qcif -f rv10 /tmp/b.rm
|
|
@end example
|
|
|
|
@item
|
|
The parameter 'q' which is displayed while encoding is the current
|
|
quantizer. The value 1 indicates that a very good quality could
|
|
be achieved. The value 31 indicates the worst quality. If q=31 appears
|
|
too often, it means that the encoder cannot compress enough to meet
|
|
your bitrate. You must either increase the bitrate, decrease the
|
|
frame rate or decrease the frame size.
|
|
|
|
@item
|
|
If your computer is not fast enough, you can speed up the
|
|
compression at the expense of the compression ratio. You can use
|
|
'-me zero' to speed up motion estimation, and '-g 0' to disable
|
|
motion estimation completely (you have only I-frames, which means it
|
|
is about as good as JPEG compression).
|
|
|
|
@item
|
|
To have very low audio bitrates, reduce the sampling frequency
|
|
(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).
|
|
|
|
@item
|
|
To have a constant quality (but a variable bitrate), use the option
|
|
'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
|
|
quality).
|
|
|
|
@end itemize
|
|
@c man end TIPS
|
|
|
|
@chapter Examples
|
|
@c man begin EXAMPLES
|
|
|
|
@section Preset files
|
|
|
|
A preset file contains a sequence of @var{option=value} pairs, one for
|
|
each line, specifying a sequence of options which can be specified also on
|
|
the command line. Lines starting with the hash ('#') character are ignored and
|
|
are used to provide comments. Empty lines are also ignored. Check the
|
|
@file{presets} directory in the FFmpeg source tree for examples.
|
|
|
|
Preset files are specified with the @code{pre} option, this option takes a
|
|
preset name as input. FFmpeg searches for a file named @var{preset_name}.avpreset in
|
|
the directories @file{$AVCONV_DATADIR} (if set), and @file{$HOME/.ffmpeg}, and in
|
|
the data directory defined at configuration time (usually @file{$PREFIX/share/ffmpeg})
|
|
in that order. For example, if the argument is @code{libx264-max}, it will
|
|
search for the file @file{libx264-max.avpreset}.
|
|
|
|
@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 -s cif -r 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 -s cif -r 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 -formats}.
|
|
|
|
@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 -vframes or -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 -i foo-%03d.jpeg -r 12 -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 -i 'foo-*.jpeg' -r 12 -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 0:3 -map 0:2 -map 0:1 -map 0:0 -c copy test12.nut
|
|
@end example
|
|
|
|
The resulting output file @file{test12.avi} will contain first four streams from
|
|
the input file 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
|
|
|
|
@chapter See Also
|
|
|
|
@ifhtml
|
|
@url{ffplay.html,ffplay}, @url{ffprobe.html,ffprobe}, @url{ffserver.html,ffserver},
|
|
@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},
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@url{ffmpeg-devices.html,ffmpeg-devices},
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|
@url{ffmpeg-protocols.html,ffmpeg-protocols},
|
|
@url{ffmpeg-filters.html,ffmpeg-filters}
|
|
@end ifhtml
|
|
|
|
@ifnothtml
|
|
ffplay(1), ffprobe(1), ffserver(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 video converter
|
|
|
|
@end ignore
|
|
|
|
@bye
|