ffmpeg.1 - oasis-root - Compiled tree of Oasis Linux based on own branch at <https://hacktivis.me/git/oasis/>

ffmpeg.1 (121187B)

.Dd August 2, 2024
.Dt FFMPEG 7
.Os
.Sh NAME
.Nm ffmpeg
.Nd ffmpeg Documentation
.Sh
.Sh Synopsis
ffmpeg [
.Va global_options
] {[
.Va input_file_options
] -i
.Pa input_url
}\&... {[
.Va output_file_options
]
.Pa output_url
}\&...
.Pp
.Sh Description
.Xr 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.
.Pp
.Xr ffmpeg
reads from an arbitrary number of input "files" (which can be regular files,
pipes, network streams, grabbing devices, etc.), specified by the
.Li -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.
.Pp
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
.Li -map
option (see the Stream selection chapter).
.Pp
To refer to input files in options, you must use their indices (0-based).
E.g. the first input file is
.Li 0 ,
the second is
.Li 1 ,
etc. Similarly, streams within a file are referred to by their indices. E.g.
.Li 2:3
refers to the fourth stream in the third input file. Also see the Stream specifiers
chapter.
.Pp
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.
.Pp
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.
.Pp
Some simple examples follow.
.Pp
.Bl -bullet
.It
Convert an input media file to a different format, by re-encoding media streams:
.Bd -literal -offset indent
ffmpeg -i input.avi output.mp4
.Ed
.Pp
.It
Set the video bitrate of the output file to 64 kbit/s:
.Bd -literal -offset indent
ffmpeg -i input.avi -b:v 64k -bufsize 64k output.mp4
.Ed
.Pp
.It
Force the frame rate of the output file to 24 fps:
.Bd -literal -offset indent
ffmpeg -i input.avi -r 24 output.mp4
.Ed
.Pp
.It
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:
.Bd -literal -offset indent
ffmpeg -r 1 -i input.m2v -r 24 output.mp4
.Ed
.El
.Pp
The format option may be needed for raw input files.
.Pp
.Sh Detailed description
The transcoding process in
.Xr ffmpeg
for each output can be described by the following diagram:
.Pp
.Bd -literal -offset indent
_______ ______________
| | | |
| input | demuxer | encoded data | decoder
| file | ---------> | packets | -----+
|_______| |______________| |
v
_________
| |
| decoded |
| frames |
|_________|
________ ______________ |
| | | | |
| output | <-------- | encoded data | <----+
| file | muxer | packets | encoder
|________| |______________|
.Ed
.Pp
.Xr 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,
.Xr ffmpeg
tries to keep them synchronized by tracking lowest timestamp on any active
input stream.
.Pp
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.
.Pp
.Ss Filtering
Before encoding,
.Xr ffmpeg
can process raw audio and video frames using filters from the libavfilter
library. Several chained filters form a filter graph.
.Xr ffmpeg
distinguishes between two types of filtergraphs: simple and complex.
.Pp
.Em Simple filtergraphs
.Pp
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:
.Pp
.Bd -literal -offset indent
_________ ______________
| | | |
| decoded | | encoded data |
| frames |\e _ | packets |
|_________| \e /||______________|
\e __________ /
simple _\e|| | / encoder
filtergraph | filtered |/
| frames |
|__________|
.Ed
.Pp
Simple filtergraphs are configured with the per-stream
.Op -filter
option (with
.Op -vf
and
.Op -af
aliases for video and audio respectively). A simple filtergraph for video
can look for example like this:
.Pp
.Bd -literal -offset indent
_______ _____________ _______ ________
| | | | | | | |
| input | ---> | deinterlace | ---> | scale | ---> | output |
|_______| |_____________| |_______| |________|
.Ed
.Pp
Note that some filters change frame properties but not frame contents. E.g.
the
.Li fps
filter in the example above changes number of frames, but does not touch the
frame contents. Another example is the
.Li setpts
filter, which only sets timestamps and otherwise passes the frames unchanged.
.Pp
.Em Complex filtergraphs
.Pp
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:
.Pp
.Bd -literal -offset indent
_________
| |
| input 0 |\e __________
|_________| \e | |
\e _________ /| output 0 |
\e | | / |__________|
_________ \e| complex | /
| | | |/
| input 1 |---->| filter |\e
|_________| | | \e __________
/| graph | \e | |
/ | | \e| output 1 |
_________ / |_________| |__________|
| | /
| input 2 |/
|_________|
.Ed
.Pp
Complex filtergraphs are configured with the
.Op -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.
.Pp
The
.Op -lavfi
option is equivalent to
.Op -filter_complex .
.Pp
A trivial example of a complex filtergraph is the
.Li 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
.Li amix
filter.
.Pp
.Ss Stream copy
Stream copy is a mode selected by supplying the
.Li copy
parameter to the
.Op -codec
option. It makes
.Xr 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:
.Pp
.Bd -literal -offset indent
_______ ______________ ________
| | | | | |
| input | demuxer | encoded data | muxer | output |
| file | ---------> | packets | -------> | file |
|_______| |______________| |________|
.Ed
.Pp
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.
.Pp
.Ss 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
.Li -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
.Op -filter_complex .
.Pp
E.g. the following example:
.Pp
.Bd -literal -offset indent
ffmpeg -i INPUT \e
-map 0:v:0 -c:v libx264 -crf 45 -f null - \e
-dec 0:0 -filter_complex '[0:v][dec:0]hstack[stack]' \e
-map '[stack]' -c:v ffv1 OUTPUT
.Ed
.Pp
reads an input video and
.Bl -bullet
.It
(line 2) encodes it with
.Li libx264
at low quality;
.Pp
.It
(line 3) decodes this encoded stream and places it side by side with the original
input video;
.Pp
.It
(line 4) combined video is then losslessly encoded and written into
.Pa OUTPUT .
.Pp
.El
.Sh Stream selection
.Xr ffmpeg
provides the
.Li -map
option for manual control of stream selection in each output file. Users can
skip
.Li -map
and let ffmpeg perform automatic stream selection as described below. The
.Li -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.
.Pp
.Ss 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.
.Pp
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.
.Pp
.Em Automatic stream selection
.Pp
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.
.Pp
It will select that stream based upon the following criteria:
.Bl -bullet
.It
for video, it is the stream with the highest resolution,
.It
for audio, it is the stream with the most channels,
.It
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.
.El
.Pp
In the case where several streams of the same type rate equally, the stream
with the lowest index is chosen.
.Pp
Data or attachment streams are not automatically selected and can only be
included using
.Li -map .
.Pp
.Em Manual stream selection
.Pp
When
.Li -map
is used, only user-mapped streams are included in that output file, with one
possible exception for filtergraph outputs described below.
.Pp
.Em Complex filtergraphs
.Pp
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.
.Pp
Complex filtergraph output streams with labeled pads must be mapped once and
exactly once.
.Pp
.Em Stream handling
.Pp
Stream handling is independent of stream selection, with an exception for
subtitles described below. Stream handling is set via the
.Li -codec
option addressed to streams within a specific
.Em output
file. In particular, codec options are applied by ffmpeg after the stream
selection process and thus do not influence the latter. If no
.Li -codec
option is specified for a stream type, ffmpeg will select the default encoder
registered by the output file muxer.
.Pp
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
.Em all
output files will fail to be processed.
.Pp
.Ss Examples
The following examples illustrate the behavior, quirks and limitations of
ffmpeg's stream selection methods.
.Pp
They assume the following three input files.
.Pp
.Bd -literal -offset indent
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)
.Ed
.Pp
.No Example: automatic stream selection
.Pp
.Bd -literal -offset indent
ffmpeg -i A.avi -i B.mp4 out1.mkv out2.wav -map 1:a -c:a copy out3.mov
.Ed
There are three output files specified, and for the first two, no
.Li -map
options are set, so ffmpeg will select streams for these two files automatically.
.Pp
.Pa 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
.Li stream 0
from
.Pa B.mp4 ,
which has the highest resolution among all the input video streams. For audio,
it will select
.Li stream 3
from
.Pa B.mp4 ,
since it has the greatest number of channels. For subtitles, it will select
.Li stream 2
from
.Pa B.mp4 ,
which is the first subtitle stream from among
.Pa A.avi
and
.Pa B.mp4 .
.Pp
.Pa out2.wav
accepts only audio streams, so only
.Li stream 3
from
.Pa B.mp4
is selected.
.Pp
For
.Pa out3.mov ,
since a
.Li -map
option is set, no automatic stream selection will occur. The
.Li -map 1:a
option will select all audio streams from the second input
.Pa B.mp4 .
No other streams will be included in this output file.
.Pp
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.
.Pp
For the third output, codec option for audio streams has been set to
.Li copy ,
so no decoding-filtering-encoding operations will occur, or
.Em can
occur. Packets of selected streams shall be conveyed from the input file and
muxed within the output file.
.Pp
.No Example: automatic subtitles selection
.Pp
.Bd -literal -offset indent
ffmpeg -i C.mkv out1.mkv -c:s dvdsub -an out2.mkv
.Ed
Although
.Pa out1.mkv
is a Matroska container file which accepts subtitle streams, only a video
and audio stream shall be selected. The subtitle stream of
.Pa 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
.Pa 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
.Li -an
disables audio stream selection for
.Pa out2.mkv .
.Pp
.No Example: unlabeled filtergraph outputs
.Pp
.Bd -literal -offset indent
ffmpeg -i A.avi -i C.mkv -i B.mp4 -filter_complex "overlay" out1.mp4 out2.srt
.Ed
A filtergraph is setup here using the
.Li -filter_complex
option and consists of a single video filter. The
.Li overlay
filter requires exactly two video inputs, but none are specified, so the first
two available video streams are used, those of
.Pa A.avi
and
.Pa C.mkv .
The output pad of the filter has no label and so is sent to the first output
file
.Pa out1.mp4 .
Due to this, automatic selection of the video stream is skipped, which would
have selected the stream in
.Pa B.mp4 .
The audio stream with most channels viz.
.Li stream 3
in
.Pa 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.
.Pp
The 2nd output file,
.Pa out2.srt ,
only accepts text-based subtitle streams. So, even though the first subtitle
stream available belongs to
.Pa C.mkv ,
it is image-based and hence skipped. The selected stream,
.Li stream 2
in
.Pa B.mp4 ,
is the first text-based subtitle stream.
.Pp
.No Example: labeled filtergraph outputs
.Pp
.Bd -literal -offset indent
ffmpeg -i A.avi -i B.mp4 -i C.mkv -filter_complex "[1:v]hue=s=0[outv];overlay;aresample" \e
-map '[outv]' -an out1.mp4 \e
out2.mkv \e
-map '[outv]' -map 1:a:0 out3.mkv
.Ed
.Pp
The above command will fail, as the output pad labelled
.Li [outv]
has been mapped twice. None of the output files shall be processed.
.Pp
.Bd -literal -offset indent
ffmpeg -i A.avi -i B.mp4 -i C.mkv -filter_complex "[1:v]hue=s=0[outv];overlay;aresample" \e
-an out1.mp4 \e
out2.mkv \e
-map 1:a:0 out3.mkv
.Ed
.Pp
This command above will also fail as the hue filter output has a label,
.Li [outv] ,
and hasn't been mapped anywhere.
.Pp
The command should be modified as follows,
.Bd -literal -offset indent
ffmpeg -i A.avi -i B.mp4 -i C.mkv -filter_complex "[1:v]hue=s=0,split=2[outv1][outv2];overlay;aresample" \e
-map '[outv1]' -an out1.mp4 \e
out2.mkv \e
-map '[outv2]' -map 1:a:0 out3.mkv
.Ed
The video stream from
.Pa 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.
.Pp
The overlay filter, requiring two video inputs, uses the first two unused
video streams. Those are the streams from
.Pa A.avi
and
.Pa C.mkv .
The overlay output isn't labelled, so it is sent to the first output file
.Pa out1.mp4 ,
regardless of the presence of the
.Li -map
option.
.Pp
The aresample filter is sent the first unused audio stream, that of
.Pa A.avi .
Since this filter output is also unlabelled, it too is mapped to the first
output file. The presence of
.Li -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
.Pa out1.mp4 .
.Pp
The video, audio and subtitle streams mapped to
.Li out2.mkv
are entirely determined by automatic stream selection.
.Pp
.Pa out3.mkv
consists of the cloned video output from the hue filter and the first audio
stream from
.Pa B.mp4 .

.Pp
.Sh Options
All the numerical options, if not specified otherwise, accept a string representing
a number as input, which may be followed by one of the SI unit prefixes, for
example: 'K', 'M', or 'G'.
.Pp
If 'i' is appended to the SI unit prefix, the complete prefix will be interpreted
as a unit prefix for binary multiples, which are based on powers of 1024 instead
of powers of 1000. Appending 'B' to the SI unit prefix multiplies the value
by 8. This allows using, for example: 'KB', 'MiB', 'G' and 'B' as number suffixes.
.Pp
Options which do not take arguments are boolean options, and set the corresponding
value to true. They can be set to false by prefixing the option name with
"no". For example using "-nofoo" will set the boolean option with name "foo"
to false.
.Pp
Options that take arguments support a special syntax where the argument given
on the command line is interpreted as a path to the file from which the actual
argument value is loaded. To use this feature, add a forward slash '/' immediately
before the option name (after the leading dash). E.g.
.Bd -literal -offset indent
ffmpeg -i INPUT -/filter:v filter.script OUTPUT
.Ed
will load a filtergraph description from the file named
.Pa filter.script .
.Pp
.Ss Stream specifiers
Some options are applied per-stream, e.g. bitrate or codec. Stream specifiers
are used to precisely specify which stream(s) a given option belongs to.
.Pp
A stream specifier is a string generally appended to the option name and separated
from it by a colon. E.g.
.Li -codec:a:1 ac3
contains the
.Li a:1
stream specifier, which matches the second audio stream. Therefore, it would
select the ac3 codec for the second audio stream.
.Pp
A stream specifier can match several streams, so that the option is applied
to all of them. E.g. the stream specifier in
.Li -b:a 128k
matches all audio streams.
.Pp
An empty stream specifier matches all streams. For example,
.Li -codec copy
or
.Li -codec: copy
would copy all the streams without reencoding.
.Pp
Possible forms of stream specifiers are:
.Bl -tag -width Ds
.It Va stream_index
Matches the stream with this index. E.g.
.Li -threads:1 4
would set the thread count for the second stream to 4. If
.Va stream_index
is used as an additional stream specifier (see below), then it selects stream
number
.Va stream_index
from the matching streams. Stream numbering is based on the order of the streams
as detected by libavformat except when a stream group specifier or program
ID is also specified. In this case it is based on the ordering of the streams
in the group or program.
.It Va stream_type[: Va additional_stream_specifier]
.Va stream_type
is one of following: 'v' or 'V' for video, 'a' for audio, 's' for subtitle,
\&'d' for data, and 't' for attachments. 'v' matches all video streams, 'V'
only matches video streams which are not attached pictures, video thumbnails
or cover arts. If
.Va additional_stream_specifier
is used, then it matches streams which both have this type and match the
.Va additional_stream_specifier .
Otherwise, it matches all streams of the specified type.
.It g: Va group_specifier[: Va additional_stream_specifier]
Matches streams which are in the group with the specifier
.Va group_specifier .
if
.Va additional_stream_specifier
is used, then it matches streams which both are part of the group and match
the
.Va additional_stream_specifier .
.Va group_specifier
may be one of the following:
.Bl -tag -width Ds
.It Va group_index
Match the stream with this group index.
.It # Va group_id or i: Va group_id
Match the stream with this group id.
.El
.It p: Va program_id[: Va additional_stream_specifier]
Matches streams which are in the program with the id
.Va program_id .
If
.Va additional_stream_specifier
is used, then it matches streams which both are part of the program and match
the
.Va additional_stream_specifier .
.Pp
.It # Va stream_id or i: Va stream_id
Match the stream by stream id (e.g. PID in MPEG-TS container).
.It m: Va key[: Va value]
Matches streams with the metadata tag
.Va key
having the specified value. If
.Va value
is not given, matches streams that contain the given tag with any value.
.It u
Matches streams with usable configuration, the codec must be defined and the
essential information such as video dimension or audio sample rate must be
present.
.Pp
Note that in
.Xr ffmpeg ,
matching by metadata will only work properly for input files.
.El
.Pp
.Ss Generic options
These options are shared amongst the ff* tools.
.Pp
.Bl -tag -width Ds
.It -L
Show license.
.Pp
.It -h, -?, -help, --help [ Va arg]
Show help. An optional parameter may be specified to print help about a specific
item. If no argument is specified, only basic (non advanced) tool options
are shown.
.Pp
Possible values of
.Va arg
are:
.Bl -tag -width Ds
.It long
Print advanced tool options in addition to the basic tool options.
.Pp
.It full
Print complete list of options, including shared and private options for encoders,
decoders, demuxers, muxers, filters, etc.
.Pp
.It decoder= Va decoder_name
Print detailed information about the decoder named
.Va decoder_name .
Use the
.Op -decoders
option to get a list of all decoders.
.Pp
.It encoder= Va encoder_name
Print detailed information about the encoder named
.Va encoder_name .
Use the
.Op -encoders
option to get a list of all encoders.
.Pp
.It demuxer= Va demuxer_name
Print detailed information about the demuxer named
.Va demuxer_name .
Use the
.Op -formats
option to get a list of all demuxers and muxers.
.Pp
.It muxer= Va muxer_name
Print detailed information about the muxer named
.Va muxer_name .
Use the
.Op -formats
option to get a list of all muxers and demuxers.
.Pp
.It filter= Va filter_name
Print detailed information about the filter named
.Va filter_name .
Use the
.Op -filters
option to get a list of all filters.
.Pp
.It bsf= Va bitstream_filter_name
Print detailed information about the bitstream filter named
.Va bitstream_filter_name .
Use the
.Op -bsfs
option to get a list of all bitstream filters.
.Pp
.It protocol= Va protocol_name
Print detailed information about the protocol named
.Va protocol_name .
Use the
.Op -protocols
option to get a list of all protocols.
.El
.Pp
.It -version
Show version.
.Pp
.It -buildconf
Show the build configuration, one option per line.
.Pp
.It -formats
Show available formats (including devices).
.Pp
.It -demuxers
Show available demuxers.
.Pp
.It -muxers
Show available muxers.
.Pp
.It -devices
Show available devices.
.Pp
.It -codecs
Show all codecs known to libavcodec.
.Pp
Note that the term 'codec' is used throughout this documentation as a shortcut
for what is more correctly called a media bitstream format.
.Pp
.It -decoders
Show available decoders.
.Pp
.It -encoders
Show all available encoders.
.Pp
.It -bsfs
Show available bitstream filters.
.Pp
.It -protocols
Show available protocols.
.Pp
.It -filters
Show available libavfilter filters.
.Pp
.It -pix_fmts
Show available pixel formats.
.Pp
.It -sample_fmts
Show available sample formats.
.Pp
.It -layouts
Show channel names and standard channel layouts.
.Pp
.It -dispositions
Show stream dispositions.
.Pp
.It -colors
Show recognized color names.
.Pp
.It -sources Va device[, Va opt1= Va val1[, Va opt2= Va val2]...]
Show autodetected sources of the input device. Some devices may provide system-dependent
source names that cannot be autodetected. The returned list cannot be assumed
to be always complete.
.Bd -literal -offset indent
ffmpeg -sources pulse,server=192.168.0.4
.Ed
.Pp
.It -sinks Va device[, Va opt1= Va val1[, Va opt2= Va val2]...]
Show autodetected sinks of the output device. Some devices may provide system-dependent
sink names that cannot be autodetected. The returned list cannot be assumed
to be always complete.
.Bd -literal -offset indent
ffmpeg -sinks pulse,server=192.168.0.4
.Ed
.Pp
.It -loglevel [ Va flags+] Va loglevel | -v [ Va flags+] Va loglevel
Set logging level and flags used by the library.
.Pp
The optional
.Va flags
prefix can consist of the following values:
.Bl -tag -width Ds
.It repeat
Indicates that repeated log output should not be compressed to the first line
and the "Last message repeated n times" line will be omitted.
.It level
Indicates that log output should add a
.Li [level]
prefix to each message line. This can be used as an alternative to log coloring,
e.g. when dumping the log to file.
.El
Flags can also be used alone by adding a '+'/'-' prefix to set/reset a single
flag without affecting other
.Va flags
or changing
.Va loglevel .
When setting both
.Va flags
and
.Va loglevel ,
a '+' separator is expected between the last
.Va flags
value and before
.Va loglevel .
.Pp
.Va loglevel
is a string or a number containing one of the following values:
.Bl -tag -width Ds
.It quiet, -8
Show nothing at all; be silent.
.It panic, 0
Only show fatal errors which could lead the process to crash, such as an assertion
failure. This is not currently used for anything.
.It fatal, 8
Only show fatal errors. These are errors after which the process absolutely
cannot continue.
.It error, 16
Show all errors, including ones which can be recovered from.
.It warning, 24
Show all warnings and errors. Any message related to possibly incorrect or
unexpected events will be shown.
.It info, 32
Show informative messages during processing. This is in addition to warnings
and errors. This is the default value.
.It verbose, 40
Same as
.Li info ,
except more verbose.
.It debug, 48
Show everything, including debugging information.
.It trace, 56
.El
.Pp
For example to enable repeated log output, add the
.Li level
prefix, and set
.Va loglevel
to
.Li verbose :
.Bd -literal -offset indent
ffmpeg -loglevel repeat+level+verbose -i input output
.Ed
Another example that enables repeated log output without affecting current
state of
.Li level
prefix flag or
.Va loglevel :
.Bd -literal -offset indent
ffmpeg [...] -loglevel +repeat
.Ed
.Pp
By default the program logs to stderr. If coloring is supported by the terminal,
colors are used to mark errors and warnings. Log coloring can be disabled
setting the environment variable
.Ev AV_LOG_FORCE_NOCOLOR ,
or can be forced setting the environment variable
.Ev AV_LOG_FORCE_COLOR .
.Pp
.It -report
Dump full command line and log output to a file named
.Li Va program- Va YYYYMMDD- Va HHMMSS.log
in the current directory. This file can be useful for bug reports. It also
implies
.Li -loglevel debug .
.Pp
Setting the environment variable
.Ev FFREPORT
to any value has the same effect. If the value is a ':'-separated key=value
sequence, these options will affect the report; option values must be escaped
if they contain special characters or the options delimiter ':' (see the \(lqQuoting
and escaping\(rq section in the ffmpeg-utils manual).
.Pp
The following options are recognized:
.Bl -tag -width Ds
.It file
set the file name to use for the report;
.Li %p
is expanded to the name of the program,
.Li %t
is expanded to a timestamp,
.Li %%
is expanded to a plain
.Li %
.It level
set the log verbosity level using a numerical value (see
.Li -loglevel ) .
.El
.Pp
For example, to output a report to a file named
.Pa ffreport.log
using a log level of
.Li 32
(alias for log level
.Li info ) :
.Pp
.Bd -literal -offset indent
FFREPORT=file=ffreport.log:level=32 ffmpeg -i input output
.Ed
.Pp
Errors in parsing the environment variable are not fatal, and will not appear
in the report.
.Pp
.It -hide_banner
Suppress printing banner.
.Pp
All FFmpeg tools will normally show a copyright notice, build options and
library versions. This option can be used to suppress printing this information.
.Pp
.It -cpuflags flags ( Em global)
Allows setting and clearing cpu flags. This option is intended for testing.
Do not use it unless you know what you're doing.
.Bd -literal -offset indent
ffmpeg -cpuflags -sse+mmx ...
ffmpeg -cpuflags mmx ...
ffmpeg -cpuflags 0 ...
.Ed
Possible flags for this option are:
.Bl -tag -width Ds
.It x86
.Bl -tag -width Ds
.It mmx
.It mmxext
.It sse
.It sse2
.It sse2slow
.It sse3
.It sse3slow
.It ssse3
.It atom
.It sse4.1
.It sse4.2
.It avx
.It avx2
.It xop
.It fma3
.It fma4
.It 3dnow
.It 3dnowext
.It bmi1
.It bmi2
.It cmov
.El
.It ARM
.Bl -tag -width Ds
.It armv5te
.It armv6
.It armv6t2
.It vfp
.It vfpv3
.It neon
.It setend
.El
.It AArch64
.Bl -tag -width Ds
.It armv8
.It vfp
.It neon
.El
.It PowerPC
.Bl -tag -width Ds
.It altivec
.El
.It Specific Processors
.Bl -tag -width Ds
.It pentium2
.It pentium3
.It pentium4
.It k6
.It k62
.It athlon
.It athlonxp
.It k8
.El
.El
.Pp
.It -cpucount Va count ( Em global)
Override detection of CPU count. This option is intended for testing. Do not
use it unless you know what you're doing.
.Bd -literal -offset indent
ffmpeg -cpucount 2
.Ed
.Pp
.It -max_alloc Va bytes
Set the maximum size limit for allocating a block on the heap by ffmpeg's
family of malloc functions. Exercise
.Sy extreme caution
when using this option. Don't use if you do not understand the full consequence
of doing so. Default is INT_MAX.
.El
.Pp
.Ss AVOptions
These options are provided directly by the libavformat, libavdevice and libavcodec
libraries. To see the list of available AVOptions, use the
.Op -help
option. They are separated into two categories:
.Bl -tag -width Ds
.It generic
These options can be set for any container, codec or device. Generic options
are listed under AVFormatContext options for containers/devices and under
AVCodecContext options for codecs.
.It private
These options are specific to the given container, device or codec. Private
options are listed under their corresponding containers/devices/codecs.
.El
.Pp
For example to write an ID3v2.3 header instead of a default ID3v2.4 to an
MP3 file, use the
.Op id3v2_version
private option of the MP3 muxer:
.Bd -literal -offset indent
ffmpeg -i input.flac -id3v2_version 3 out.mp3
.Ed
.Pp
All codec AVOptions are per-stream, and thus a stream specifier should be
attached to them:
.Bd -literal -offset indent
ffmpeg -i multichannel.mxf -map 0:v:0 -map 0:a:0 -map 0:a:0 -c:a:0 ac3 -b:a:0 640k -ac:a:1 2 -c:a:1 aac -b:2 128k out.mp4
.Ed
.Pp
In the above example, a multichannel audio stream is mapped twice for output.
The first instance is encoded with codec ac3 and bitrate 640k. The second
instance is downmixed to 2 channels and encoded with codec aac. A bitrate
of 128k is specified for it using absolute index of the output stream.
.Pp
Note: the
.Op -nooption
syntax cannot be used for boolean AVOptions, use
.Op -option 0
/
.Op -option 1 .
.Pp
Note: the old undocumented way of specifying per-stream AVOptions by prepending
v/a/s to the options name is now obsolete and will be removed soon.
.Pp
.Ss Main options
.Bl -tag -width Ds
.It -f Va fmt ( Em 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.
.Pp
.It -i Va url ( Em input)
input file url
.Pp
.It -y ( Em global)
Overwrite output files without asking.
.Pp
.It -n ( Em global)
Do not overwrite output files, and exit immediately if a specified output
file already exists.
.Pp
.It -stream_loop Va number ( Em input)
Set number of times input stream shall be looped. Loop 0 means no loop, loop
-1 means infinite loop.
.Pp
.It -recast_media ( Em 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.
.Pp
.It -c[: Va stream_specifier] Va codec ( Em input/output,per-stream)
.It -codec[: Va stream_specifier] Va codec ( Em 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.
.Va codec
is the name of a decoder/encoder or a special value
.Li copy
(output only) to indicate that the stream is not to be re-encoded.
.Pp
For example
.Bd -literal -offset indent
ffmpeg -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
.Ed
encodes all video streams with libx264 and copies all audio streams.
.Pp
For each stream, the last matching
.Li c
option is applied, so
.Bd -literal -offset indent
ffmpeg -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
.Ed
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.
.Pp
.It -t Va duration ( Em input/output)
When used as an input option (before
.Li -i ) ,
limit the
.Va duration
of data read from the input file.
.Pp
When used as an output option (before an output url), stop writing the output
after its duration reaches
.Va duration .
.Pp
.Va duration
must be a time duration specification, see time duration syntax,,the Time
duration section in the ffmpeg-utils(1) manual,ffmpeg-utils.
.Pp
-to and -t are mutually exclusive and -t has priority.
.Pp
.It -to Va position ( Em input/output)
Stop writing the output or reading the input at
.Va position .
.Va position
must be a time duration specification, see time duration syntax,,the Time
duration section in the ffmpeg-utils(1) manual,ffmpeg-utils.
.Pp
-to and -t are mutually exclusive and -t has priority.
.Pp
.It -fs Va limit_size ( Em 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.
.Pp
.It -ss Va position ( Em input/output)
When used as an input option (before
.Li -i ) ,
seeks in this input file to
.Va position .
Note that in most formats it is not possible to seek exactly, so
.Xr ffmpeg
will seek to the closest seek point before
.Va position .
When transcoding and
.Op -accurate_seek
is enabled (the default), this extra segment between the seek point and
.Va position
will be decoded and discarded. When doing stream copy or when
.Op -noaccurate_seek
is used, it will be preserved.
.Pp
When used as an output option (before an output url), decodes but discards
input until the timestamps reach
.Va position .
.Pp
.Va position
must be a time duration specification, see time duration syntax,,the Time
duration section in the ffmpeg-utils(1) manual,ffmpeg-utils.
.Pp
.It -sseof Va position ( Em input)
.Pp
Like the
.Li -ss
option but relative to the "end of file". That is negative values are earlier
in the file, 0 is at EOF.
.Pp
.It -isync Va input_index ( Em input)
Assign an input as a sync source.
.Pp
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
.Li copyts
is set then
.Li start_at_zero
must also be set. If either of the inputs has no starting timestamp then no
sync adjustment is made.
.Pp
Acceptable values are those that refer to a valid ffmpeg input index. If the
sync reference is the target index itself or
.Va -1 ,
then no adjustment is made to target timestamps. A sync reference may not
itself be synced to any other input.
.Pp
Default value is
.Va -1 .
.Pp
.It -itsoffset Va offset ( Em input)
Set the input time offset.
.Pp
.Va offset
must be a time duration specification, see time duration syntax,,the Time
duration section in the ffmpeg-utils(1) manual,ffmpeg-utils.
.Pp
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
.Va offset .
.Pp
.It -itsscale Va scale ( Em input,per-stream)
Rescale input timestamps.
.Va scale
should be a floating point number.
.Pp
.It -timestamp Va date ( Em output)
Set the recording timestamp in the container.
.Pp
.Va date
must be a date specification, see date syntax,,the Date section in the ffmpeg-utils(1)
manual,ffmpeg-utils.
.Pp
.It -metadata[:metadata_specifier] Va key= Va value ( Em output,per-metadata)
Set a metadata key/value pair.
.Pp
An optional
.Va metadata_specifier
may be given to set metadata on streams, chapters or programs. See
.Li -map_metadata
documentation for details.
.Pp
This option overrides metadata set with
.Li -map_metadata .
It is also possible to delete metadata by using an empty value.
.Pp
For example, for setting the title in the output file:
.Bd -literal -offset indent
ffmpeg -i in.avi -metadata title="my title" out.flv
.Ed
.Pp
To set the language of the first audio stream:
.Bd -literal -offset indent
ffmpeg -i INPUT -metadata:s:a:0 language=eng OUTPUT
.Ed
.Pp
.It -disposition[:stream_specifier] Va value ( Em output,per-stream)
Sets the disposition for a stream.
.Pp
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.
.Pp
.Va 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.
.Pp
If no
.Li -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.
.Pp
The
.Li -dispositions
option lists the known dispositions.
.Pp
For example, to make the second audio stream the default stream:
.Bd -literal -offset indent
ffmpeg -i in.mkv -c copy -disposition:a:1 default out.mkv
.Ed
.Pp
To make the second subtitle stream the default stream and remove the default
disposition from the first subtitle stream:
.Bd -literal -offset indent
ffmpeg -i in.mkv -c copy -disposition:s:0 0 -disposition:s:1 default out.mkv
.Ed
.Pp
To add an embedded cover/thumbnail:
.Bd -literal -offset indent
ffmpeg -i in.mp4 -i IMAGE -map 0 -map 1 -c copy -c:v:1 png -disposition:v:1 attached_pic out.mp4
.Ed
.Pp
Not all muxers support embedded thumbnails, and those who do, only support
a few formats, like JPEG or PNG.
.Pp
.It -program [title= Va title:][program_num= Va program_num:]st= Va stream[:st= Va stream...] ( Em output)
.Pp
Creates a program with the specified
.Va title ,
.Va program_num
and adds the specified
.Va stream
(s) to it.
.Pp
.It -stream_group type= Va type:st= Va stream[:st= Va stream][:stg= Va stream_group][:id= Va stream_group_id...] ( Em output)
.Pp
Creates a stream group of the specified
.Va type ,
.Va stream_group_id
and adds the specified
.Va stream
(s) and/or previously defined
.Va stream_group
(s) to it.
.Pp
.Va type
can be one of the following:
.Bl -tag -width Ds
.It iamf_audio_element
Groups
.Va stream
s that belong to the same IAMF Audio Element
.Pp
For this group
.Va type ,
the following options are available
.Bl -tag -width Ds
.It audio_element_type
The Audio Element type. The following values are supported:
.Pp
.Bl -tag -width Ds
.It channel
Scalable channel audio representation
.It scene
Ambisonics representation
.El
.Pp
.It 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
.Pp
.Bl -tag -width Ds
.It parameter_id
An identifier parameters blocks in frames may refer to
.It dmixp_mode
A pre-defined combination of demixing parameters
.El
.Pp
.It 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
.Pp
.Bl -tag -width Ds
.It parameter_id
An identifier parameters blocks in frames may refer to
.El
.Pp
.It 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.
.Pp
It takes the following ":"-separated key=value options
.Pp
.Bl -tag -width Ds
.It ch_layout
The layer's channel layout
.It flags
The following flags are available:
.Pp
.Bl -tag -width Ds
.It recon_gain
Wether to signal if recon_gain is present as metadata in parameter blocks
within frames
.El
.Pp
.It output_gain
.It output_gain_flags
Which channels output_gain applies to. The following flags are available:
.Pp
.Bl -tag -width Ds
.It FL
.It FR
.It BL
.It BR
.It TFL
.It TFR
.El
.Pp
.It ambisonics_mode
The ambisonics mode. This has no effect if audio_element_type is set to channel.
.Pp
The following values are supported:
.Pp
.Bl -tag -width Ds
.It mono
Each ambisonics channel is coded as an individual mono stream in the group
.El
.Pp
.El
.It default_w
Default weight value
.Pp
.El
.It iamf_mix_presentation
Groups
.Va stream
s that belong to all IAMF Audio Element the same IAMF Mix Presentation references
.Pp
For this group
.Va type ,
the following options are available
.Pp
.Bl -tag -width Ds
.It 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.
.Pp
It takes the following ":"-separated key=value options
.Pp
.Bl -tag -width Ds
.It 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
.It parameter_rate
The sample rate duration fields in parameters blocks in frames that refer
to this
.Va parameter_id
are expressed as
.It default_mix_gain
Default mix gain value to apply when there are no parameter blocks sharing
the same
.Va parameter_id
for a given frame
.Pp
.It 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.
.Pp
It takes the following ":"-separated key=value options:
.Pp
.Bl -tag -width Ds
.It stg
The
.Va stream_group_id
for an Audio Element which this sub-mix refers to
.It 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
.It parameter_rate
The sample rate duration fields in parameters blocks in frames that refer
to this
.Va parameter_id
are expressed as
.It default_mix_gain
Default mix gain value to apply when there are no parameter blocks sharing
the same
.Va parameter_id
for a given frame
.It 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
.Va annotations
.It 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
.Va audio_element_type
is set to channel.
.Pp
The following values are supported:
.Pp
.Bl -tag -width Ds
.It stereo
.It binaural
.El
.Pp
.El
.It 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.
.Pp
It takes the following ":"-separated key=value options:
.Pp
.Bl -tag -width Ds
.It layout_type
.Pp
.Bl -tag -width Ds
.It loudspeakers
The layout follows the loudspeaker sound system convention of ITU-2051-3.
.It binaural
The layout is binaural.
.El
.Pp
.It 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
.Va layout_type
is set to binaural.
.It integrated_loudness
The program integrated loudness information, as defined in ITU-1770-4.
.It digital_peak
The digital (sampled) peak value of the audio signal, as defined in ITU-1770-4.
.It true_peak
The true peak of the audio signal, as defined in ITU-1770-4.
.It dialog_anchored_loudness
The Dialogue loudness information, as defined in ITU-1770-4.
.It album_anchored_loudness
The Album loudness information, as defined in ITU-1770-4.
.El
.Pp
.El
.It 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
.Va annotations
s
.El
.Pp
.El
.It -target Va type ( Em output)
Specify target file type (
.Li vcd ,
.Li svcd ,
.Li dvd ,
.Li dv ,
.Li dv50 ) .
.Va type
may be prefixed with
.Li pal- ,
.Li ntsc-
or
.Li film-
to use the corresponding standard. All the format options (bitrate, codecs,
buffer sizes) are then set automatically. You can just type:
.Pp
.Bd -literal -offset indent
ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
.Ed
.Pp
Nevertheless you can specify additional options as long as you know they do
not conflict with the standard, as in:
.Pp
.Bd -literal -offset indent
ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
.Ed
.Pp
The parameters set for each target are as follows.
.Pp
.Sy VCD
.Bd -literal -offset indent
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
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
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
.Ed
.Pp
.Sy SVCD
.Bd -literal -offset indent
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
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
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
.Ed
.Pp
.Sy DVD
.Bd -literal -offset indent
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
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
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
.Ed
.Pp
.Sy DV
.Bd -literal -offset indent
pal:
-f dv
-s 720x576 -pix_fmt yuv420p -r 25
-ar 48000 -ac 2
ntsc:
-f dv
-s 720x480 -pix_fmt yuv411p -r 30000/1001
-ar 48000 -ac 2
film:
-f dv
-s 720x480 -pix_fmt yuv411p -r 24000/1001
-ar 48000 -ac 2
.Ed
The
.Li dv50
target is identical to the
.Li dv
target except that the pixel format set is
.Li yuv422p
for all three standards.
.Pp
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.
.Pp
.It -dn ( Em 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
.Li -discard
option to disable streams individually.
.Pp
As an output option, disables data recording i.e. automatic selection or mapping
of any data stream. For full manual control see the
.Li -map
option.
.Pp
.It -dframes Va number ( Em output)
Set the number of data frames to output. This is an obsolete alias for
.Li -frames:d ,
which you should use instead.
.Pp
.It -frames[: Va stream_specifier] Va framecount ( Em output,per-stream)
Stop writing to the stream after
.Va framecount
frames.
.Pp
.It -q[: Va stream_specifier] Va q ( Em output,per-stream)
.It -qscale[: Va stream_specifier] Va q ( Em output,per-stream)
Use fixed quality scale (VBR). The meaning of
.Va q
/
.Va qscale
is codec-dependent. If
.Va qscale
is used without a
.Va 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.
.Pp
.It -filter[: Va stream_specifier] Va filtergraph ( Em output,per-stream)
Create the filtergraph specified by
.Va filtergraph
and use it to filter the stream.
.Pp
.Va 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
.Li in ,
and the output to the label
.Li out .
See the ffmpeg-filters manual for more information about the filtergraph syntax.
.Pp
See the filter_complex_option,,-filter_complex option if you want to create
filtergraphs with multiple inputs and/or outputs.
.Pp
.It -reinit_filter[: Va stream_specifier] Va integer ( Em 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
.Li 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.
.Pp
.It -filter_threads Va nb_threads ( Em 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.
.Pp
.It -pre[: Va stream_specifier] Va preset_name ( Em output,per-stream)
Specify the preset for matching stream(s).
.Pp
.It -stats ( Em global)
Print encoding progress/statistics. It is on by default, to explicitly disable
it you need to specify
.Li -nostats .
.Pp
.It -stats_period Va time ( Em global)
Set period at which encoding progress/statistics are updated. Default is 0.5
seconds.
.Pp
.It -progress Va url ( Em global)
Send program-friendly progress information to
.Va url .
.Pp
Progress information is written periodically and at the end of the encoding
process. It is made of "
.Va key
=
.Va value "
lines.
.Va key
consists of only alphanumeric characters. The last key of a sequence of progress
information is always "progress".
.Pp
The update period is set using
.Li -stats_period .
.Pp
.It -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
.Li -nostdin .
.Pp
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
.Li ffmpeg ... < /dev/null
but it requires a shell.
.Pp
.It -debug_ts ( Em 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.
.Pp
See also the option
.Li -fdebug ts .
.Pp
.It -attach Va filename ( Em 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
.Li -map
or automatic mappings).
.Pp
Note that for Matroska you also have to set the mimetype metadata tag:
.Bd -literal -offset indent
ffmpeg -i INPUT -attach DejaVuSans.ttf -metadata:s:2 mimetype=application/x-truetype-font out.mkv
.Ed
(assuming that the attachment stream will be third in the output file).
.Pp
.It -dump_attachment[: Va stream_specifier] Va filename ( Em input,per-stream)
Extract the matching attachment stream into a file named
.Va filename .
If
.Va filename
is empty, then the value of the
.Li filename
metadata tag will be used.
.Pp
E.g. to extract the first attachment to a file named 'out.ttf':
.Bd -literal -offset indent
ffmpeg -dump_attachment:t:0 out.ttf -i INPUT
.Ed
To extract all attachments to files determined by the
.Li filename
tag:
.Bd -literal -offset indent
ffmpeg -dump_attachment:t "" -i INPUT
.Ed
.Pp
Technical note -- attachments are implemented as codec extradata, so this
option can actually be used to extract extradata from any stream, not just
attachments.
.El
.Pp
.Ss Video Options
.Bl -tag -width Ds
.It -vframes Va number ( Em output)
Set the number of video frames to output. This is an obsolete alias for
.Li -frames:v ,
which you should use instead.
.It -r[: Va stream_specifier] Va fps ( Em input/output,per-stream)
Set frame rate (Hz value, fraction or abbreviation).
.Pp
As an input option, ignore any timestamps stored in the file and instead generate
timestamps assuming constant frame rate
.Va fps .
This is not the same as the
.Op -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
.Op -framerate
instead of the input option
.Op -r .
.Pp
As an output option:
.Bl -tag -width Ds
.It video encoding
Duplicate or drop frames right before encoding them to achieve constant output
frame rate
.Va fps .
.Pp
.It video streamcopy
Indicate to the muxer that
.Va fps
is the stream frame rate. No data is dropped or duplicated in this case. This
may produce invalid files if
.Va fps
does not match the actual stream frame rate as determined by packet timestamps.
See also the
.Li setts
bitstream filter.
.Pp
.El
.It -fpsmax[: Va stream_specifier] Va fps ( Em output,per-stream)
Set maximum frame rate (Hz value, fraction or abbreviation).
.Pp
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
.Li -r .
It is ignored during streamcopy.
.Pp
.It -s[: Va stream_specifier] Va size ( Em input/output,per-stream)
Set frame size.
.Pp
As an input option, this is a shortcut for the
.Op 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.
.Pp
As an output option, this inserts the
.Li scale
video filter to the
.Em end
of the corresponding filtergraph. Please use the
.Li scale
filter directly to insert it at the beginning or some other place.
.Pp
The format is
.Li wxh
(default - same as source).
.Pp
.It -aspect[: Va stream_specifier] Va aspect ( Em output,per-stream)
Set the video display aspect ratio specified by
.Va aspect .
.Pp
.Va aspect
can be a floating point number string, or a string of the form
.Va num
:
.Va den ,
where
.Va num
and
.Va 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.
.Pp
If used together with
.Op -vcodec copy ,
it will affect the aspect ratio stored at container level, but not the aspect
ratio stored in encoded frames, if it exists.
.Pp
.It -display_rotation[: Va stream_specifier] Va rotation ( Em input,per-stream)
Set video rotation metadata.
.Pp
.Va rotation
is a decimal number specifying the amount in degree by which the video should
be rotated counter-clockwise before being displayed.
.Pp
This option overrides the rotation/display transform metadata stored in the
file, if any. When the video is being transcoded (rather than copied) and
.Li -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.
.Pp
If the
.Li -display_hflip
and/or
.Li -display_vflip
options are given, they are applied after the rotation specified by this option.
.Pp
.It -display_hflip[: Va stream_specifier] ( Em input,per-stream)
Set whether on display the image should be horizontally flipped.
.Pp
See the
.Li -display_rotation
option for more details.
.Pp
.It -display_vflip[: Va stream_specifier] ( Em input,per-stream)
Set whether on display the image should be vertically flipped.
.Pp
See the
.Li -display_rotation
option for more details.
.Pp
.It -vn ( Em 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
.Li -discard
option to disable streams individually.
.Pp
As an output option, disables video recording i.e. automatic selection or
mapping of any video stream. For full manual control see the
.Li -map
option.
.Pp
.It -vcodec Va codec ( Em output)
Set the video codec. This is an alias for
.Li -codec:v .
.Pp
.It -pass[: Va stream_specifier] Va n ( Em 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:
.Bd -literal -offset indent
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
.Ed
.Pp
.It -passlogfile[: Va stream_specifier] Va prefix ( Em output,per-stream)
Set two-pass log file name prefix to
.Va prefix ,
the default file name prefix is \(lqffmpeg2pass\(rq. The complete file name will be
.Pa PREFIX-N.log ,
where N is a number specific to the output stream
.Pp
.It -vf Va filtergraph ( Em output)
Create the filtergraph specified by
.Va filtergraph
and use it to filter the stream.
.Pp
This is an alias for
.Li -filter:v ,
see the filter_option,,-filter option.
.Pp
.It -autorotate
Automatically rotate the video according to file metadata. Enabled by default,
use
.Op -noautorotate
to disable it.
.Pp
.It -autoscale
Automatically scale the video according to the resolution of first frame.
Enabled by default, use
.Op -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.
.El
.Pp
.Ss Advanced Video options
.Bl -tag -width Ds
.It -pix_fmt[: Va stream_specifier] Va format ( Em input/output,per-stream)
Set pixel format. Use
.Li -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
.Va pix_fmt
is prefixed by a
.Li + ,
ffmpeg will exit with an error if the requested pixel format can not be selected,
and automatic conversions inside filtergraphs are disabled. If
.Va pix_fmt
is a single
.Li + ,
ffmpeg selects the same pixel format as the input (or graph output) and automatic
conversions are disabled.
.Pp
.It -sws_flags Va flags ( Em input/output)
Set default flags for the libswscale library. These flags are used by automatically
inserted
.Li scale
filters and those within simple filtergraphs, if not overridden within the
filtergraph definition.
.Pp
See the scaler_options,,ffmpeg-scaler manual,ffmpeg-scaler for a list of scaler
options.
.Pp
.It -rc_override[: Va stream_specifier] Va override ( Em 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.
.Pp
.It -vstats
Dump video coding statistics to
.Pa vstats_HHMMSS.log .
See the vstats_file_format,,vstats file format section for the format description.
.Pp
.It -vstats_file Va file
Dump video coding statistics to
.Va file .
See the vstats_file_format,,vstats file format section for the format description.
.Pp
.It -vstats_version Va file
Specify which version of the vstats format to use. Default is
.Li 2 .
See the vstats_file_format,,vstats file format section for the format description.
.Pp
.It -vtag Va fourcc/tag ( Em output)
Force video tag/fourcc. This is an alias for
.Li -tag:v .
.Pp
.It -force_key_frames[: Va stream_specifier] Va time[, Va time...] ( Em output,per-stream)
.It -force_key_frames[: Va stream_specifier] expr: Va expr ( Em output,per-stream)
.It -force_key_frames[: Va stream_specifier] source ( Em output,per-stream)
.Pp
.Va force_key_frames
can take arguments of the following form:
.Pp
.Bl -tag -width Ds
.It Va time[, Va 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
.Li -enc_time_base .
.Pp
If one of the times is "
.Li chapters
[
.Va delta
]", it is expanded into the time of the beginning of all chapters in the file,
shifted by
.Va 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.
.Pp
For example, to insert a key frame at 5 minutes, plus key frames 0.1 second
before the beginning of every chapter:
.Bd -literal -offset indent
-force_key_frames 0:05:00,chapters-0.1
.Ed
.Pp
.It expr: Va expr
If the argument is prefixed with
.Li expr: ,
the string
.Va expr
is interpreted like an expression and is evaluated for each frame. A key frame
is forced in case the evaluation is non-zero.
.Pp
The expression in
.Va expr
can contain the following constants:
.Bl -tag -width Ds
.It n
the number of current processed frame, starting from 0
.It n_forced
the number of forced frames
.It prev_forced_n
the number of the previous forced frame, it is
.Li NAN
when no keyframe was forced yet
.It prev_forced_t
the time of the previous forced frame, it is
.Li NAN
when no keyframe was forced yet
.It t
the time of the current processed frame
.El
.Pp
For example to force a key frame every 5 seconds, you can specify:
.Bd -literal -offset indent
-force_key_frames expr:gte(t,n_forced*5)
.Ed
.Pp
To force a key frame 5 seconds after the time of the last forced one, starting
from second 13:
.Bd -literal -offset indent
-force_key_frames expr:if(isnan(prev_forced_t),gte(t,13),gte(t,prev_forced_t+5))
.Ed
.Pp
.It source
If the argument is
.Li 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.
.Pp
.El
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.
.Pp
.It -copyinkf[: Va stream_specifier] ( Em output,per-stream)
When doing stream copy, copy also non-key frames found at the beginning.
.Pp
.It -init_hw_device Va type[= Va name][: Va device[, Va key=value...]]
Initialise a new hardware device of type
.Va type
called
.Va name ,
using the given device parameters. If no name is specified it will receive
a default name of the form "
.Va type
%d".
.Pp
The meaning of
.Va device
and the following arguments depends on the device type:
.Bl -tag -width Ds
.It cuda
.Va device
is the number of the CUDA device.
.Pp
The following options are recognized:
.Bl -tag -width Ds
.It primary_ctx
If set to 1, uses the primary device context instead of creating a new one.
.El
.Pp
Examples:
.Bl -tag -width Ds
.It -init_hw_device cuda:1
Choose the second device on the system.
.Pp
.It -init_hw_device cuda:0,primary_ctx=1
Choose the first device and use the primary device context.
.El
.Pp
.It dxva2
.Va device
is the number of the Direct3D 9 display adapter.
.Pp
.It d3d11va
.Va 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
.Li vendor_id .
.Pp
Examples:
.Bl -tag -width Ds
.It -init_hw_device d3d11va
Create a d3d11va device on the default Direct3D 11 display adapter.
.Pp
.It -init_hw_device d3d11va:1
Create a d3d11va device on the Direct3D 11 display adapter specified by index
1.
.Pp
.It -init_hw_device d3d11va:,vendor_id=0x8086
Create a d3d11va device on the first Direct3D 11 display adapter whose hardware
VendorId is 0x8086.
.El
.Pp
.It vaapi
.Va 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 (
.Em $DISPLAY )
and then the first DRM render node (
.Em /dev/dri/renderD128 ) ,
or the default DirectX adapter on Windows.
.Pp
The following options are recognized:
.Bl -tag -width Ds
.It kernel_driver
When
.Va 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
.Em drm
and
.Em vaapi
are enabled.
.El
.Pp
Examples:
.Bl -tag -width Ds
.It -init_hw_device vaapi
Create a vaapi device on the default device.
.Pp
.It -init_hw_device vaapi:/dev/dri/renderD129
Create a vaapi device on DRM render node
.Pa /dev/dri/renderD129 .
.Pp
.It -init_hw_device vaapi:1
Create a vaapi device on DirectX adapter 1.
.Pp
.It -init_hw_device vaapi:,kernel_driver=i915
Create a vaapi device on a device associated with kernel driver
.Li i915 .
.El
.Pp
.It vdpau
.Va device
is an X11 display name. If not specified, it will attempt to open the default
X11 display (
.Em $DISPLAY ) .
.Pp
.It qsv
.Va device
selects a value in
.Li MFX_IMPL_* .
Allowed values are:
.Bl -tag -width Ds
.It auto
.It sw
.It hw
.It auto_any
.It hw_any
.It hw2
.It hw3
.It hw4
.El
If not specified,
.Li auto_any
is used. (Note that it may be easier to achieve the desired result for QSV
by creating the platform-appropriate subdevice (
.Li dxva2
or
.Li d3d11va
or
.Li vaapi )
and then deriving a QSV device from that.)
.Pp
The following options are recognized:
.Bl -tag -width Ds
.It child_device
Specify a DRM render node on Linux or DirectX adapter on Windows.
.It child_device_type
Choose platform-appropriate subdevice type. On Windows
.Li d3d11va
is used as default subdevice type when
.Li --enable-libvpl
is specified at configuration time,
.Li dxva2
is used as default subdevice type when
.Li --enable-libmfx
is specified at configuration time. On Linux user can use
.Li vaapi
only as subdevice type.
.El
.Pp
Examples:
.Bl -tag -width Ds
.It -init_hw_device qsv:hw,child_device=/dev/dri/renderD129
Create a QSV device with
.Li MFX_IMPL_HARDWARE
on DRM render node
.Pa /dev/dri/renderD129 .
.Pp
.It -init_hw_device qsv:hw,child_device=1
Create a QSV device with
.Li MFX_IMPL_HARDWARE
on DirectX adapter 1.
.Pp
.It -init_hw_device qsv:hw,child_device_type=d3d11va
Choose the GPU subdevice with type
.Li d3d11va
and create QSV device with
.Li MFX_IMPL_HARDWARE .
.Pp
.It -init_hw_device qsv:hw,child_device_type=dxva2
Choose the GPU subdevice with type
.Li dxva2
and create QSV device with
.Li MFX_IMPL_HARDWARE .
.Pp
.It -init_hw_device qsv:hw,child_device=1,child_device_type=d3d11va
Create a QSV device with
.Li MFX_IMPL_HARDWARE
on DirectX adapter 1 with subdevice type
.Li d3d11va .
.Pp
.It -init_hw_device vaapi=va:/dev/dri/renderD129 -init_hw_device qsv=hw1@ Va va
Create a VAAPI device called
.Li va
on
.Pa /dev/dri/renderD129 ,
then derive a QSV device called
.Li hw1
from device
.Li va .
.Pp
.El
.It opencl
.Va device
selects the platform and device as
.Em platform_index.device_index .
.Pp
The set of devices can also be filtered using the key-value pairs to find
only devices matching particular platform or device strings.
.Pp
The strings usable as filters are:
.Bl -tag -width Ds
.It platform_profile
.It platform_version
.It platform_name
.It platform_vendor
.It platform_extensions
.It device_name
.It device_vendor
.It driver_version
.It device_version
.It device_profile
.It device_extensions
.It device_type
.El
.Pp
The indices and filters must together uniquely select a device.
.Pp
Examples:
.Bl -tag -width Ds
.It -init_hw_device opencl:0.1
Choose the second device on the first platform.
.Pp
.It -init_hw_device opencl:,device_name=Foo9000
Choose the device with a name containing the string
.Em Foo9000 .
.Pp
.It -init_hw_device opencl:1,device_type=gpu,device_extensions=cl_khr_fp16
Choose the GPU device on the second platform supporting the
.Em cl_khr_fp16
extension.
.El
.Pp
.It vulkan
If
.Va device
is an integer, it selects the device by its index in a system-dependent list
of devices. If
.Va device
is any other string, it selects the first device with a name containing that
string as a substring.
.Pp
The following options are recognized:
.Bl -tag -width Ds
.It debug
If set to 1, enables the validation layer, if installed.
.It linear_images
If set to 1, images allocated by the hwcontext will be linear and locally
mappable.
.It instance_extensions
A plus separated list of additional instance extensions to enable.
.It device_extensions
A plus separated list of additional device extensions to enable.
.El
.Pp
Examples:
.Bl -tag -width Ds
.It -init_hw_device vulkan:1
Choose the second device on the system.
.Pp
.It -init_hw_device vulkan:RADV
Choose the first device with a name containing the string
.Em RADV .
.Pp
.It -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.
.El
.Pp
.El
.It -init_hw_device Va type[= Va name]@ Va source
Initialise a new hardware device of type
.Va type
called
.Va name ,
deriving it from the existing device with the name
.Va source .
.Pp
.It -init_hw_device list
List all hardware device types supported in this build of ffmpeg.
.Pp
.It -filter_hw_device Va name
Pass the hardware device called
.Va name
to all filters in any filter graph. This can be used to set the device to
upload to with the
.Li hwupload
filter, or the device to map to with the
.Li 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.
.Pp
This is a global setting, so all filters will receive the same device.
.Pp
.It -hwaccel[: Va stream_specifier] Va hwaccel ( Em input,per-stream)
Use hardware acceleration to decode the matching stream(s). The allowed values
of
.Va hwaccel
are:
.Bl -tag -width Ds
.It none
Do not use any hardware acceleration (the default).
.Pp
.It auto
Automatically select the hardware acceleration method.
.Pp
.It vdpau
Use VDPAU (Video Decode and Presentation API for Unix) hardware acceleration.
.Pp
.It dxva2
Use DXVA2 (DirectX Video Acceleration) hardware acceleration.
.Pp
.It d3d11va
Use D3D11VA (DirectX Video Acceleration) hardware acceleration.
.Pp
.It vaapi
Use VAAPI (Video Acceleration API) hardware acceleration.
.Pp
.It qsv
Use the Intel QuickSync Video acceleration for video transcoding.
.Pp
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.
.Pp
For it to work, both the decoder and the encoder must support QSV acceleration
and no filters must be used.
.El
.Pp
This option has no effect if the selected hwaccel is not available or not
supported by the chosen decoder.
.Pp
Note that most acceleration methods are intended for playback and will not
be faster than software decoding on modern CPUs. Additionally,
.Xr 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.
.Pp
.It -hwaccel_device[: Va stream_specifier] Va hwaccel_device ( Em input,per-stream)
Select a device to use for hardware acceleration.
.Pp
This option only makes sense when the
.Op -hwaccel
option is also specified. It can either refer to an existing device created
with
.Op -init_hw_device
by name, or it can create a new device as if
.Li -init_hw_device
.Va type
:
.Va hwaccel_device
were called immediately before.
.Pp
.It -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.
.Pp
.It -fix_sub_duration_heartbeat[: Va 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.
.Pp
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.
.Pp
Requires
.Op -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.
.Pp
.El
.Ss Audio Options
.Bl -tag -width Ds
.It -aframes Va number ( Em output)
Set the number of audio frames to output. This is an obsolete alias for
.Li -frames:a ,
which you should use instead.
.It -ar[: Va stream_specifier] Va freq ( Em 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.
.It -aq Va q ( Em output)
Set the audio quality (codec-specific, VBR). This is an alias for -q:a.
.It -ac[: Va stream_specifier] Va channels ( Em 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.
.It -an ( Em 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
.Li -discard
option to disable streams individually.
.Pp
As an output option, disables audio recording i.e. automatic selection or
mapping of any audio stream. For full manual control see the
.Li -map
option.
.It -acodec Va codec ( Em input/output)
Set the audio codec. This is an alias for
.Li -codec:a .
.It -sample_fmt[: Va stream_specifier] Va sample_fmt ( Em output,per-stream)
Set the audio sample format. Use
.Li -sample_fmts
to get a list of supported sample formats.
.Pp
.It -af Va filtergraph ( Em output)
Create the filtergraph specified by
.Va filtergraph
and use it to filter the stream.
.Pp
This is an alias for
.Li -filter:a ,
see the filter_option,,-filter option.
.El
.Pp
.Ss Advanced Audio options
.Bl -tag -width Ds
.It -atag Va fourcc/tag ( Em output)
Force audio tag/fourcc. This is an alias for
.Li -tag:a .
.It -guess_layout_max Va channels ( Em 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
.Xr 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.
.El
.Pp
.Ss Subtitle options
.Bl -tag -width Ds
.It -scodec Va codec ( Em input/output)
Set the subtitle codec. This is an alias for
.Li -codec:s .
.It -sn ( Em 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
.Li -discard
option to disable streams individually.
.Pp
As an output option, disables subtitle recording i.e. automatic selection
or mapping of any subtitle stream. For full manual control see the
.Li -map
option.
.El
.Pp
.Ss Advanced Subtitle options
.Bl -tag -width Ds
.It -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.
.Pp
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.
.Pp
.It -canvas_size Va size
Set the size of the canvas used to render subtitles.
.Pp
.El
.Ss Advanced options
.Bl -tag -width Ds
.It -map [-] Va input_file_id[: Va stream_specifier][?] | Va [linklabel] ( Em output)
.Pp
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
.Li -i ) ,
the second takes an output from some complex filtergraph (specified with
.Li -filter_complex ) .
.Pp
In the first form, an output stream is created for every stream from the input
file with the index
.Va input_file_id .
If
.Va stream_specifier
is given, only those streams that match the specifier are used (see the Stream
specifiers section for the
.Va stream_specifier
syntax).
.Pp
A
.Li -
character before the stream identifier creates a "negative" mapping. It disables
matching streams from already created mappings.
.Pp
A trailing
.Li ?
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.
.Pp
An alternative
.Va [linklabel]
form will map outputs from complex filter graphs (see the
.Op -filter_complex
option) to the output file.
.Va linklabel
must correspond to a defined output link label in the graph.
.Pp
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
.Li -map
options are given on the commandline.
.Pp
Using this option disables the default mappings for this output file.
.Pp
Examples:
.Pp
.Bl -tag -width Ds
.It map everything
To map ALL streams from the first input file to output
.Bd -literal -offset indent
ffmpeg -i INPUT -map 0 output
.Ed
.Pp
.It select specific stream
If you have two audio streams in the first input file, these streams are identified
by
.Va 0:0
and
.Va 0:1 .
You can use
.Li -map
to select which streams to place in an output file. For example:
.Bd -literal -offset indent
ffmpeg -i INPUT -map 0:1 out.wav
.Ed
will map the second input stream in
.Pa INPUT
to the (single) output stream in
.Pa out.wav .
.Pp
.It create multiple streams
To select the stream with index 2 from input file
.Pa a.mov
(specified by the identifier
.Va 0:2 ) ,
and stream with index 6 from input
.Pa b.mov
(specified by the identifier
.Va 1:6 ) ,
and copy them to the output file
.Pa out.mov :
.Bd -literal -offset indent
ffmpeg -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
.Ed
.Pp
.It create multiple streams 2
To select all video and the third audio stream from an input file:
.Bd -literal -offset indent
ffmpeg -i INPUT -map 0:v -map 0:a:2 OUTPUT
.Ed
.Pp
.It negative map
To map all the streams except the second audio, use negative mappings
.Bd -literal -offset indent
ffmpeg -i INPUT -map 0 -map -0:a:1 OUTPUT
.Ed
.Pp
.It optional map
To map the video and audio streams from the first input, and using the trailing
.Li ? ,
ignore the audio mapping if no audio streams exist in the first input:
.Bd -literal -offset indent
ffmpeg -i INPUT -map 0:v -map 0:a? OUTPUT
.Ed
.Pp
.It map by language
To pick the English audio stream:
.Bd -literal -offset indent
ffmpeg -i INPUT -map 0:m:language:eng OUTPUT
.Ed
.Pp
.El
.It -ignore_unknown
Ignore input streams with unknown type instead of failing if copying such
streams is attempted.
.Pp
.It -copy_unknown
Allow input streams with unknown type to be copied instead of failing if copying
such streams is attempted.
.Pp
.It -map_metadata[: Va metadata_spec_out] Va infile[: Va metadata_spec_in] ( Em output,per-metadata)
Set metadata information of the next output file from
.Va infile .
Note that those are file indices (zero-based), not filenames. Optional
.Va metadata_spec_in/out
parameters specify, which metadata to copy. A metadata specifier can have
the following forms:
.Bl -tag -width Ds
.It Va g
global metadata, i.e. metadata that applies to the whole file
.Pp
.It Va s[: Va stream_spec]
per-stream metadata.
.Va stream_spec
is a stream specifier as described in the 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.
.Pp
.It Va c: Va chapter_index
per-chapter metadata.
.Va chapter_index
is the zero-based chapter index.
.Pp
.It Va p: Va program_index
per-program metadata.
.Va program_index
is the zero-based program index.
.El
If metadata specifier is omitted, it defaults to global.
.Pp
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.
.Pp
For example to copy metadata from the first stream of the input file to global
metadata of the output file:
.Bd -literal -offset indent
ffmpeg -i in.ogg -map_metadata 0:s:0 out.mp3
.Ed
.Pp
To do the reverse, i.e. copy global metadata to all audio streams:
.Bd -literal -offset indent
ffmpeg -i in.mkv -map_metadata:s:a 0:g out.mkv
.Ed
Note that simple
.Li 0
would work as well in this example, since global metadata is assumed by default.
.Pp
.It -map_chapters Va input_file_index ( Em output)
Copy chapters from input file with index
.Va 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.
.Pp
.It -benchmark ( Em 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.
.It -benchmark_all ( Em global)
Show benchmarking information during the encode. Shows real, system and user
time used in various steps (audio/video encode/decode).
.It -timelimit Va duration ( Em global)
Exit after ffmpeg has been running for
.Va duration
seconds in CPU user time.
.It -dump ( Em global)
Dump each input packet to stderr.
.It -hex ( Em global)
When dumping packets, also dump the payload.
.It -readrate Va speed ( Em input)
Limit input read speed.
.Pp
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
.Li 1
represents real-time speed and is equivalent to
.Li -re .
.Pp
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.
.Pp
It is useful for when flow speed of output packets is important, such as live
streaming.
.It -re ( Em input)
Read input at native frame rate. This is equivalent to setting
.Li -readrate 1 .
.It -readrate_initial_burst Va seconds
Set an initial read burst time, in seconds, after which
.Op -re/-readrate
will be enforced.
.It -vsync Va parameter ( Em global)
.It -fps_mode[: Va stream_specifier] Va parameter ( Em 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.
.Pp
For compatibility reasons some of the values for vsync can be specified as
numbers (shown in parentheses in the following table).
.Pp
.Bl -tag -width Ds
.It passthrough (0)
Each frame is passed with its timestamp from the demuxer to the muxer.
.It cfr (1)
Frames will be duplicated and dropped to achieve exactly the requested constant
frame rate.
.It vfr (2)
Frames are passed through with their timestamp or dropped so as to prevent
2 frames from having the same timestamp.
.It auto (-1)
Chooses between cfr and vfr depending on muxer capabilities. This is the default
method.
.El
.Pp
Note that the timestamps may be further modified by the muxer, after this.
For example, in the case that the format option
.Op avoid_negative_ts
is enabled.
.Pp
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.
.Pp
.It -frame_drop_threshold Va 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.
.Pp
.It -apad Va parameters ( Em output,per-stream)
Pad the output audio stream(s). This is the same as applying
.Li -af apad .
Argument is a string of filter parameters composed the same as with the
.Li apad
filter.
.Li -shortest
must be set for this output for the option to take effect.
.Pp
.It -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.
.Pp
Note that, depending on the
.Op vsync
option or on specific muxer processing (e.g. in case the format option
.Op avoid_negative_ts
is enabled) the output timestamps may mismatch with the input timestamps even
when this option is selected.
.Pp
.It -start_at_zero
When used with
.Op copyts ,
shift input timestamps so they start at zero.
.Pp
This means that using e.g.
.Li -ss 50
will make output timestamps start at 50 seconds, regardless of what timestamp
the input file started at.
.Pp
.It -copytb Va mode
Specify how to set the encoder timebase when stream copying.
.Va mode
is an integer numeric value, and can assume one of the following values:
.Pp
.Bl -tag -width Ds
.It 1
Use the demuxer timebase.
.Pp
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.
.Pp
.It 0
Use the decoder timebase.
.Pp
The time base is copied to the output encoder from the corresponding input
decoder.
.Pp
.It -1
Try to make the choice automatically, in order to generate a sane output.
.El
.Pp
Default value is -1.
.Pp
.It -enc_time_base[: Va stream_specifier] Va timebase ( Em output,per-stream)
Set the encoder timebase.
.Va timebase
can assume one of the following values:
.Pp
.Bl -tag -width Ds
.It 0
Assign a default value according to the media type.
.Pp
For video - use 1/framerate, for audio - use 1/samplerate.
.Pp
.It demux
Use the timebase from the demuxer.
.Pp
.It filter
Use the timebase from the filtergraph.
.Pp
.It a positive number
Use the provided number as the timebase.
.Pp
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)
.El
.Pp
Default value is 0.
.Pp
.It -bitexact ( Em input/output)
Enable bitexact mode for (de)muxer and (de/en)coder
.It -shortest ( Em output)
Finish encoding when the shortest output stream ends.
.Pp
Note that this option may require buffering frames, which introduces extra
latency. The maximum amount of this latency may be controlled with the
.Li -shortest_buf_duration
option.
.Pp
.It -shortest_buf_duration Va duration ( Em output)
The
.Li -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).
.Pp
This option controls the maximum duration of buffered frames in seconds. Larger
values may allow the
.Li -shortest
option to produce more accurate results, but increase memory use and latency.
.Pp
The default value is 10 seconds.
.Pp
.It -dts_delta_threshold Va threshold
Timestamp discontinuity delta threshold, expressed as a decimal number of
seconds.
.Pp
The timestamp discontinuity correction enabled by this option is only applied
to input formats accepting timestamp discontinuity (for which the
.Li AVFMT_TS_DISCONT
flag is enabled), e.g. MPEG-TS and HLS, and is automatically disabled when
employing the
.Li -copyts
option (unless wrapping is detected).
.Pp
If a timestamp discontinuity is detected whose absolute value is greater than
.Va threshold ,
ffmpeg will remove the discontinuity by decreasing/increasing the current
DTS and PTS by the corresponding delta value.
.Pp
The default value is 10.
.Pp
.It -dts_error_threshold Va threshold
Timestamp error delta threshold, expressed as a decimal number of seconds.
.Pp
The timestamp correction enabled by this option is only applied to input formats
not accepting timestamp discontinuity (for which the
.Li AVFMT_TS_DISCONT
flag is not enabled).
.Pp
If a timestamp discontinuity is detected whose absolute value is greater than
.Va threshold ,
ffmpeg will drop the PTS/DTS timestamp value.
.Pp
The default value is
.Li 3600*30
(30 hours), which is arbitrarily picked and quite conservative.
.Pp
.It -muxdelay Va seconds ( Em output)
Set the maximum demux-decode delay.
.It -muxpreload Va seconds ( Em output)
Set the initial demux-decode delay.
.It -streamid Va output-stream-index: Va new-value ( Em 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.
.Pp
For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for
an output mpegts file:
.Bd -literal -offset indent
ffmpeg -i inurl -streamid 0:33 -streamid 1:36 out.ts
.Ed
.Pp
.It -bsf[: Va stream_specifier] Va bitstream_filters ( Em 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).
.Pp
.Va bitstream_filters
is a comma-separated list of bitstream filter specifications, each of the
form
.Bd -literal -offset indent
filter[=optname0=optval0:optname1=optval1:...]
.Ed
Any of the ',=:' characters that are to be a part of an option value need
to be escaped with a backslash.
.Pp
Use the
.Li -bsfs
option to get the list of bitstream filters.
.Pp
E.g.
.Bd -literal -offset indent
ffmpeg -bsf:v h264_mp4toannexb -i h264.mp4 -c:v copy -an out.h264
.Ed
applies the
.Li h264_mp4toannexb
bitstream filter (which converts MP4-encapsulated H.264 stream to Annex B)
to the
.Em input
video stream.
.Pp
On the other hand,
.Bd -literal -offset indent
ffmpeg -i file.mov -an -vn -bsf:s mov2textsub -c:s copy -f rawvideo sub.txt
.Ed
applies the
.Li mov2textsub
bitstream filter (which extracts text from MOV subtitles) to the
.Em output
subtitle stream. Note, however, that since both examples use
.Li -c copy ,
it matters little whether the filters are applied on input or output - that
would change if transcoding was happening.
.Pp
.It -tag[: Va stream_specifier] Va codec_tag ( Em input/output,per-stream)
Force a tag/fourcc for matching streams.
.Pp
.It -timecode Va hh: Va mm: Va ssSEP Va ff
Specify Timecode for writing.
.Va SEP
is ':' for non drop timecode and ';' (or '.') for drop.
.Bd -literal -offset indent
ffmpeg -i input.mpg -timecode 01:02:03.04 -r 30000/1001 -s ntsc output.mpg
.Ed
.Pp
.It -filter_complex Va filtergraph ( Em 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
.Op -filter
options.
.Va filtergraph
is a description of the filtergraph, as described in the \(lqFiltergraph syntax\(rq
section of the ffmpeg-filters manual.
.Pp
Input link labels must refer to either input streams or loopback decoders.
For input streams, use the
.Li [file_index:stream_specifier]
syntax (i.e. the same as
.Op -map
uses). If
.Va stream_specifier
matches multiple streams, the first one will be used.
.Pp
For decoders, the link label must be [dec:
.Va dec_idx
], where
.Va dec_idx
is the index of the loopback decoder to be connected to given input.
.Pp
An unlabeled input will be connected to the first unused input stream of the
matching type.
.Pp
Output link labels are referred to with
.Op -map .
Unlabeled outputs are added to the first output file.
.Pp
Note that with this option it is possible to use only lavfi sources without
normal input files.
.Pp
For example, to overlay an image over video
.Bd -literal -offset indent
ffmpeg -i video.mkv -i image.png -filter_complex '[0:v][1:v]overlay[out]' -map
\&'[out]' out.mkv
.Ed
Here
.Li [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.
.Pp
Assuming there is only one video stream in each input file, we can omit input
labels, so the above is equivalent to
.Bd -literal -offset indent
ffmpeg -i video.mkv -i image.png -filter_complex 'overlay[out]' -map
\&'[out]' out.mkv
.Ed
.Pp
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
.Bd -literal -offset indent
ffmpeg -i video.mkv -i image.png -filter_complex 'overlay' out.mkv
.Ed
.Pp
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.
.Pp
For example, to hardcode subtitles on top of a DVB-T recording stored in MPEG-TS
format, delaying the subtitles by 1 second:
.Bd -literal -offset indent
ffmpeg -i input.ts -filter_complex \e
'[#0x2ef] setpts=PTS+1/TB [sub] ; [#0x2d0] [sub] overlay' \e
-sn -map '#0x2dc' output.mkv
.Ed
(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)
.Pp
To generate 5 seconds of pure red video using lavfi
.Li color
source:
.Bd -literal -offset indent
ffmpeg -filter_complex 'color=c=red' -t 5 out.mkv
.Ed
.Pp
.It -filter_complex_threads Va nb_threads ( Em global)
Defines how many threads are used to process a filter_complex graph. Similar
to filter_threads but used for
.Li -filter_complex
graphs only. The default is the number of available CPUs.
.Pp
.It -lavfi Va filtergraph ( Em global)
Define a complex filtergraph, i.e. one with arbitrary number of inputs and/or
outputs. Equivalent to
.Op -filter_complex .
.Pp
.It -accurate_seek ( Em input)
This option enables or disables accurate seeking in input files with the
.Op -ss
option. It is enabled by default, so seeking is accurate when transcoding.
Use
.Op -noaccurate_seek
to disable it, which may be useful e.g. when copying some streams and transcoding
the others.
.Pp
.It -seek_timestamp ( Em input)
This option enables or disables seeking by timestamp in input files with the
.Op -ss
option. It is disabled by default. If enabled, the argument to the
.Op -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.
.Pp
.It -thread_queue_size Va size ( Em 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.
.Pp
For output, this option specified the maximum number of packets that may be
queued to each muxing thread.
.Pp
.It -sdp_file Va file ( Em global)
Print sdp information for an output stream to
.Va 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).
.Pp
.It -discard ( Em input)
Allows discarding specific streams or frames from streams. Any input stream
can be fully discarded, using value
.Li all
whereas selective discarding of frames from a stream occurs at the demuxer
and is not supported by all demuxers.
.Pp
.Bl -tag -width Ds
.It none
Discard no frame.
.Pp
.It default
Default, which discards no frames.
.Pp
.It noref
Discard all non-reference frames.
.Pp
.It bidir
Discard all bidirectional frames.
.Pp
.It nokey
Discard all frames excepts keyframes.
.Pp
.It all
Discard all frames.
.El
.Pp
.It -abort_on Va flags ( Em global)
Stop and abort on various conditions. The following flags are available:
.Pp
.Bl -tag -width Ds
.It empty_output
No packets were passed to the muxer, the output is empty.
.It empty_output_stream
No packets were passed to the muxer in some of the output streams.
.El
.Pp
.It -max_error_rate ( Em 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.
.Pp
.It -xerror ( Em global)
Stop and exit on error
.Pp
.It -max_muxing_queue_size Va packets ( Em 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.
.Pp
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.
.Pp
.It -muxing_queue_data_threshold Va bytes ( Em 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.
.Pp
.It -auto_conversion_filters ( Em global)
Enable automatically inserting format conversion filters in all filter graphs,
including those defined by
.Op -vf ,
.Op -af ,
.Op -filter_complex
and
.Op -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
.Li -noauto_conversion_filters .
.Pp
.It -bits_per_raw_sample[: Va stream_specifier] Va value ( Em output,per-stream)
Declare the number of bits per raw sample in the given output stream to be
.Va 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.
.Pp
.It -stats_enc_pre[: Va stream_specifier] Va path ( Em output,per-stream)
.It -stats_enc_post[: Va stream_specifier] Va path ( Em output,per-stream)
.It -stats_mux_pre[: Va stream_specifier] Va path ( Em output,per-stream)
Write per-frame encoding information about the matching streams into the file
given by
.Va path .
.Pp
.Op -stats_enc_pre
writes information about raw video or audio frames right before they are sent
for encoding, while
.Op -stats_enc_post
writes information about encoded packets as they are received from the encoder.
.Op -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
.Op -stats_enc_pre_fmt
/
.Op -stats_enc_post_fmt
/
.Op -stats_mux_pre_fmt .
.Pp
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.
.Pp
.It -stats_enc_pre_fmt[: Va stream_specifier] Va format_spec ( Em output,per-stream)
.It -stats_enc_post_fmt[: Va stream_specifier] Va format_spec ( Em output,per-stream)
.It -stats_mux_pre_fmt[: Va stream_specifier] Va format_spec ( Em output,per-stream)
Specify the format for the lines written with
.Op -stats_enc_pre
/
.Op -stats_enc_post
/
.Op -stats_mux_pre .
.Pp
.Va format_spec
is a string that may contain directives of the form
.Va {fmt} .
.Va format_spec
is backslash-escaped --- use \e{, \e}, and \e\e to write a literal {, }, or \e, respectively,
into the output.
.Pp
The directives given with
.Va fmt
may be one of the following:
.Bl -tag -width Ds
.It fidx
Index of the output file.
.Pp
.It sidx
Index of the output stream in the file.
.Pp
.It 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.
.Pp
.It 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.
.Pp
.It tb
Timebase in which this frame/packet's timestamps are expressed, as a rational
number
.Va num/den .
Note that encoder and muxer may use different timebases.
.Pp
.It tbi
Timebase for
.Va ptsi ,
as a rational number
.Va num/den .
Available when
.Va ptsi
is available,
.Va 0/1
otherwise.
.Pp
.It pts
Presentation timestamp of the frame or packet, as an integer. Should be multiplied
by the timebase to compute presentation time.
.Pp
.It ptsi
Presentation timestamp of the input frame (see
.Va ni ) ,
as an integer. Should be multiplied by
.Va tbi
to compute presentation time. Printed as (2^63 - 1 = 9223372036854775807)
when not available.
.Pp
.It t
Presentation time of the frame or packet, as a decimal number. Equal to
.Va pts
multiplied by
.Va tb .
.Pp
.It ti
Presentation time of the input frame (see
.Va ni ) ,
as a decimal number. Equal to
.Va ptsi
multiplied by
.Va tbi .
Printed as inf when not available.
.Pp
.It dts ( Em packet)
Decoding timestamp of the packet, as an integer. Should be multiplied by the
timebase to compute presentation time.
.Pp
.It dt ( Em packet)
Decoding time of the frame or packet, as a decimal number. Equal to
.Va dts
multiplied by
.Va tb .
.Pp
.It sn ( Em frame,audio)
Number of audio samples sent to the encoder so far.
.Pp
.It samp ( Em frame,audio)
Number of audio samples in the frame.
.Pp
.It size ( Em packet)
Size of the encoded packet in bytes.
.Pp
.It br ( Em packet)
Current bitrate in bits per second.
.Pp
.It abr ( Em packet)
Average bitrate for the whole stream so far, in bits per second, -1 if it
cannot be determined at this point.
.Pp
.It key ( Em packet)
Character 'K' if the packet contains a keyframe, character 'N' otherwise.
.El
.Pp
Directives tagged with
.Em packet
may only be used with
.Op -stats_enc_post_fmt
and
.Op -stats_mux_pre_fmt .
.Pp
Directives tagged with
.Em frame
may only be used with
.Op -stats_enc_pre_fmt .
.Pp
Directives tagged with
.Em audio
may only be used with audio streams.
.Pp
The default format strings are:
.Bl -tag -width Ds
.It pre-encoding
{fidx} {sidx} {n} {t}
.It post-encoding
{fidx} {sidx} {n} {t}
.El
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.
.Pp
Note that stats for different streams written into the same file may have
different formats.
.Pp
.El
.Ss Preset files
A preset file contains a sequence of
.Va option
=
.Va 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
.Pa presets
directory in the FFmpeg source tree for examples.
.Pp
There are two types of preset files: ffpreset and avpreset files.
.Pp
.Em ffpreset files
.Pp
ffpreset files are specified with the
.Li vpre ,
.Li apre ,
.Li spre ,
and
.Li fpre
options. The
.Li 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
.Li vpre ,
.Li apre ,
and
.Li spre
options, the options specified in a preset file are applied to the currently
selected codec of the same type as the preset option.
.Pp
The argument passed to the
.Li vpre ,
.Li apre ,
and
.Li spre
preset options identifies the preset file to use according to the following
rules:
.Pp
First ffmpeg searches for a file named
.Va arg
\&.ffpreset in the directories
.Pa $FFMPEG_DATADIR
(if set), and
.Pa $HOME/.ffmpeg ,
and in the datadir defined at configuration time (usually
.Pa PREFIX/share/ffmpeg )
or in a
.Pa ffpresets
folder along the executable on win32, in that order. For example, if the argument
is
.Li libvpx-1080p ,
it will search for the file
.Pa libvpx-1080p.ffpreset .
.Pp
If no such file is found, then ffmpeg will search for a file named
.Va codec_name
-
.Va arg
\&.ffpreset in the above-mentioned directories, where
.Va 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
.Li -vcodec libvpx
and use
.Li -vpre 1080p ,
then it will search for the file
.Pa libvpx-1080p.ffpreset .
.Pp
.Em avpreset files
.Pp
avpreset files are specified with the
.Li pre
option. They work similar to ffpreset files, but they only allow encoder-
specific options. Therefore, an
.Va option
=
.Va value
pair specifying an encoder cannot be used.
.Pp
When the
.Li pre
option is specified, ffmpeg will look for files with the suffix .avpreset
in the directories
.Pa $AVCONV_DATADIR
(if set), and
.Pa $HOME/.avconv ,
and in the datadir defined at configuration time (usually
.Pa PREFIX/share/ffmpeg ) ,
in that order.
.Pp
First ffmpeg searches for a file named
.Va codec_name
-
.Va arg
\&.avpreset in the above-mentioned directories, where
.Va 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
.Li -vcodec libvpx
and use
.Li -pre 1080p ,
then it will search for the file
.Pa libvpx-1080p.avpreset .
.Pp
If no such file is found, then ffmpeg will search for a file named
.Va arg
\&.avpreset in the same directories.
.Pp
.Ss vstats file format
The
.Li -vstats
and
.Li -vstats_file
options enable generation of a file containing statistics about the generated
video outputs.
.Pp
The
.Li -vstats_version
option controls the format version of the generated file.
.Pp
With version
.Li 1
the format is:
.Bd -literal -offset indent
frame= FRAME q= FRAME_QUALITY PSNR= PSNR f_size= FRAME_SIZE s_size= STREAM_SIZEkB time= TIMESTAMP br= BITRATEkbits/s avg_br= AVERAGE_BITRATEkbits/s
.Ed
.Pp
With version
.Li 2
the format is:
.Bd -literal -offset indent
out= OUT_FILE_INDEX st= OUT_FILE_STREAM_INDEX frame= FRAME_NUMBER q= FRAME_QUALITYf PSNR= PSNR f_size= FRAME_SIZE s_size= STREAM_SIZEkB time= TIMESTAMP br= BITRATEkbits/s avg_br= AVERAGE_BITRATEkbits/s
.Ed
.Pp
The value corresponding to each key is described below:
.Bl -tag -width Ds
.It avg_br
average bitrate expressed in Kbits/s
.Pp
.It br
bitrate expressed in Kbits/s
.Pp
.It frame
number of encoded frame
.Pp
.It out
out file index
.Pp
.It PSNR
Peak Signal to Noise Ratio
.Pp
.It q
quality of the frame
.Pp
.It f_size
encoded packet size expressed as number of bytes
.Pp
.It s_size
stream size expressed in KiB
.Pp
.It st
out file stream index
.Pp
.It time
time of the packet
.Pp
.It type
picture type
.El
.Pp
See also the stats_enc_options,,-stats_enc options for an alternative way
to show encoding statistics.
.Pp
.Sh Examples
.Ss Video and Audio grabbing
If you specify the input format and device then ffmpeg can grab video and
audio directly.
.Pp
.Bd -literal -offset indent
ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
.Ed
.Pp
Or with an ALSA audio source (mono input, card id 1) instead of OSS:
.Bd -literal -offset indent
ffmpeg -f alsa -ac 1 -i hw:1 -f video4linux2 -i /dev/video0 /tmp/out.mpg
.Ed
.Pp
Note that you must activate the right video source and channel before launching
ffmpeg with any TV viewer such as
.Lk http://linux.bytesex.org/xawtv/
by Gerd Knorr. You also have to set the audio recording levels correctly with
a standard mixer.
.Pp
.Ss X11 grabbing
Grab the X11 display with ffmpeg via
.Pp
.Bd -literal -offset indent
ffmpeg -f x11grab -video_size cif -framerate 25 -i :0.0 /tmp/out.mpg
.Ed
.Pp
0.0 is display.screen number of your X11 server, same as the DISPLAY environment
variable.
.Pp
.Bd -literal -offset indent
ffmpeg -f x11grab -video_size cif -framerate 25 -i :0.0+10,20 /tmp/out.mpg
.Ed
.Pp
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.
.Pp
.Ss Video and Audio file format conversion
Any supported file format and protocol can serve as input to ffmpeg:
.Pp
Examples:
.Bl -bullet
.It
You can use YUV files as input:
.Pp
.Bd -literal -offset indent
ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
.Ed
.Pp
It will use the files:
.Bd -literal -offset indent
/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
.Ed
.Pp
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
.Op -s
option if ffmpeg cannot guess it.
.Pp
.It
You can input from a raw YUV420P file:
.Pp
.Bd -literal -offset indent
ffmpeg -i /tmp/test.yuv /tmp/out.avi
.Ed
.Pp
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.
.Pp
.It
You can output to a raw YUV420P file:
.Pp
.Bd -literal -offset indent
ffmpeg -i mydivx.avi hugefile.yuv
.Ed
.Pp
.It
You can set several input files and output files:
.Pp
.Bd -literal -offset indent
ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
.Ed
.Pp
Converts the audio file a.wav and the raw YUV video file a.yuv to MPEG file
a.mpg.
.Pp
.It
You can also do audio and video conversions at the same time:
.Pp
.Bd -literal -offset indent
ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
.Ed
.Pp
Converts a.wav to MPEG audio at 22050 Hz sample rate.
.Pp
.It
You can encode to several formats at the same time and define a mapping from
input stream to output streams:
.Pp
.Bd -literal -offset indent
ffmpeg -i /tmp/a.wav -map 0:a -b:a 64k /tmp/a.mp2 -map 0:a -b:a 128k /tmp/b.mp2
.Ed
.Pp
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.
.Pp
.It
You can transcode decrypted VOBs:
.Pp
.Bd -literal -offset indent
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
.Ed
.Pp
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
.Li --enable-libmp3lame
to configure. The mapping is particularly useful for DVD transcoding to get
the desired audio language.
.Pp
NOTE: To see the supported input formats, use
.Li ffmpeg -demuxers .
.Pp
.It
You can extract images from a video, or create a video from many images:
.Pp
For extracting images from a video:
.Bd -literal -offset indent
ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
.Ed
.Pp
This will extract one video frame per second from the video and will output
them in files named
.Pa foo-001.jpeg ,
.Pa foo-002.jpeg ,
etc. Images will be rescaled to fit the new WxH values.
.Pp
If you want to extract just a limited number of frames, you can use the above
command in combination with the
.Li -frames:v
or
.Li -t
option, or in combination with -ss to start extracting from a certain point
in time.
.Pp
For creating a video from many images:
.Bd -literal -offset indent
ffmpeg -f image2 -framerate 12 -i foo-%03d.jpeg -s WxH foo.avi
.Ed
.Pp
The syntax
.Li 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.
.Pp
When importing an image sequence, -i also supports expanding shell-like wildcard
patterns (globbing) internally, by selecting the image2-specific
.Li -pattern_type glob
option.
.Pp
For example, for creating a video from filenames matching the glob pattern
.Li foo-*.jpeg :
.Bd -literal -offset indent
ffmpeg -f image2 -pattern_type glob -framerate 12 -i 'foo-*.jpeg' -s WxH foo.avi
.Ed
.Pp
.It
You can put many streams of the same type in the output:
.Pp
.Bd -literal -offset indent
ffmpeg -i test1.avi -i test2.avi -map 1:1 -map 1:0 -map 0:1 -map 0:0 -c copy -y test12.nut
.Ed
.Pp
The resulting output file
.Pa test12.nut
will contain the first four streams from the input files in reverse order.
.Pp
.It
To force CBR video output:
.Bd -literal -offset indent
ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
.Ed
.Pp
.It
The four options lmin, lmax, mblmin and mblmax use 'lambda' units, but you
may use the QP2LAMBDA constant to easily convert from 'q' units:
.Bd -literal -offset indent
ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
.Ed
.Pp
.El
.Sh See Also
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)
.Pp
.Sh Authors
The FFmpeg developers.
.Pp
For details about the authorship, see the Git history of the project (https://git.ffmpeg.org/ffmpeg),
e.g. by typing the command
.Xr git log
in the FFmpeg source directory, or browsing the online repository at
.Lk https://git.ffmpeg.org/ffmpeg .
.Pp
Maintainers for the specific components are listed in the file
.Pa MAINTAINERS
in the source code tree.
.Pp