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Rusty-slicer/third-party/ffmpeg/ffmpeg-git-20240213-amd64-static/manpages/ffmpeg.txt

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the app is working but unsafe af
2024-03-01 13:47:42 +00:00
FFMPEG(1) FFMPEG(1)
NAME
ffmpeg - ffmpeg media converter
SYNOPSIS
ffmpeg [global_options] {[input_file_options] -i input_url} ...
{[output_file_options] output_url} ...
DESCRIPTION
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.
ffmpeg reads from an arbitrary number of input "files" (which can be
regular files, pipes, network streams, grabbing devices, etc.),
specified by the "-i" option, and writes to an arbitrary number of
output "files", which are specified by a plain output url. Anything
found on the command line which cannot be interpreted as an option is
considered to be an output url.
Each input or output url can, in principle, contain any number of
streams of different types (video/audio/subtitle/attachment/data). The
allowed number and/or types of streams may be limited by the container
format. Selecting which streams from which inputs will go into which
output is either done automatically or with the "-map" option (see the
Stream selection chapter).
To refer to input files in options, you must use their indices
(0-based). E.g. the first input file is 0, the second is 1, etc.
Similarly, streams within a file are referred to by their indices. E.g.
"2:3" refers to the fourth stream in the third input file. Also see the
Stream specifiers chapter.
As a general rule, options are applied to the next specified file.
Therefore, order is important, and you can have the same option on the
command line multiple times. Each occurrence is then applied to the
next input or output file. Exceptions from this rule are the global
options (e.g. verbosity level), which should be specified first.
Do not mix input and output files -- first specify all input files,
then all output files. Also do not mix options which belong to
different files. All options apply ONLY to the next input or output
file and are reset between files.
Some simple examples follow.
o Convert an input media file to a different format, by re-encoding
media streams:
ffmpeg -i input.avi output.mp4
o Set the video bitrate of the output file to 64 kbit/s:
ffmpeg -i input.avi -b:v 64k -bufsize 64k output.mp4
o Force the frame rate of the output file to 24 fps:
ffmpeg -i input.avi -r 24 output.mp4
o 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:
ffmpeg -r 1 -i input.m2v -r 24 output.mp4
The format option may be needed for raw input files.
DETAILED DESCRIPTION
The transcoding process in ffmpeg for each output can be described by
the following diagram:
_______ ______________
| | | |
| input | demuxer | encoded data | decoder
| file | ---------> | packets | -----+
|_______| |______________| |
v
_________
| |
| decoded |
| frames |
|_________|
________ ______________ |
| | | | |
| output | <-------- | encoded data | <----+
| file | muxer | packets | encoder
|________| |______________|
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, ffmpeg tries to keep them synchronized
by tracking lowest timestamp on any active input stream.
Encoded packets are then passed to the decoder (unless streamcopy is
selected for the stream, see further for a description). The decoder
produces uncompressed frames (raw video/PCM audio/...) which can be
processed further by filtering (see next section). After filtering, the
frames are passed to the encoder, which encodes them and outputs
encoded packets. Finally, those are passed to the muxer, which writes
the encoded packets to the output file.
Filtering
Before encoding, ffmpeg can process raw audio and video frames using
filters from the libavfilter library. Several chained filters form a
filter graph. ffmpeg distinguishes between two types of filtergraphs:
simple and complex.
Simple filtergraphs
Simple filtergraphs are those that have exactly one input and output,
both of the same type. In the above diagram they can be represented by
simply inserting an additional step between decoding and encoding:
_________ ______________
| | | |
| decoded | | encoded data |
| frames |\ _ | packets |
|_________| \ /||______________|
\ __________ /
simple _\|| | / encoder
filtergraph | filtered |/
| frames |
|__________|
Simple filtergraphs are configured with the per-stream -filter option
(with -vf and -af aliases for video and audio respectively). A simple
filtergraph for video can look for example like this:
_______ _____________ _______ ________
| | | | | | | |
| input | ---> | deinterlace | ---> | scale | ---> | output |
|_______| |_____________| |_______| |________|
Note that some filters change frame properties but not frame contents.
E.g. the "fps" filter in the example above changes number of frames,
but does not touch the frame contents. Another example is the "setpts"
filter, which only sets timestamps and otherwise passes the frames
unchanged.
Complex filtergraphs
Complex filtergraphs are those which cannot be described as simply a
linear processing chain applied to one stream. This is the case, for
example, when the graph has more than one input and/or output, or when
output stream type is different from input. They can be represented
with the following diagram:
_________
| |
| input 0 |\ __________
|_________| \ | |
\ _________ /| output 0 |
\ | | / |__________|
_________ \| complex | /
| | | |/
| input 1 |---->| filter |\
|_________| | | \ __________
/| graph | \ | |
/ | | \| output 1 |
_________ / |_________| |__________|
| | /
| input 2 |/
|_________|
Complex filtergraphs are configured with the -filter_complex option.
Note that this option is global, since a complex filtergraph, by its
nature, cannot be unambiguously associated with a single stream or
file.
The -lavfi option is equivalent to -filter_complex.
A trivial example of a complex filtergraph is the "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 "amix"
filter.
Stream copy
Stream copy is a mode selected by supplying the "copy" parameter to the
-codec option. It makes 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:
_______ ______________ ________
| | | | | |
| input | demuxer | encoded data | muxer | output |
| file | ---------> | packets | -------> | file |
|_______| |______________| |________|
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.
STREAM SELECTION
ffmpeg provides the "-map" option for manual control of stream
selection in each output file. Users can skip "-map" and let ffmpeg
perform automatic stream selection as described below. The "-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.
Description
The sub-sections that follow describe the various rules that are
involved in stream selection. The examples that follow next show how
these rules are applied in practice.
While every effort is made to accurately reflect the behavior of the
program, FFmpeg is under continuous development and the code may have
changed since the time of this writing.
Automatic stream selection
In the absence of any map options for a particular output file, ffmpeg
inspects the output format to check which type of streams can be
included in it, viz. video, audio and/or subtitles. For each acceptable
stream type, ffmpeg will pick one stream, when available, from among
all the inputs.
It will select that stream based upon the following criteria:
o for video, it is the stream with the highest resolution,
o for audio, it is the stream with the most channels,
o 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.
In the case where several streams of the same type rate equally, the
stream with the lowest index is chosen.
Data or attachment streams are not automatically selected and can only
be included using "-map".
Manual stream selection
When "-map" is used, only user-mapped streams are included in that
output file, with one possible exception for filtergraph outputs
described below.
Complex filtergraphs
If there are any complex filtergraph output streams with unlabeled
pads, they will be added to the first output file. This will lead to a
fatal error if the stream type is not supported by the output format.
In the absence of the map option, the inclusion of these streams leads
to the automatic stream selection of their types being skipped. If map
options are present, these filtergraph streams are included in addition
to the mapped streams.
Complex filtergraph output streams with labeled pads must be mapped
once and exactly once.
Stream handling
Stream handling is independent of stream selection, with an exception
for subtitles described below. Stream handling is set via the "-codec"
option addressed to streams within a specific output file. In
particular, codec options are applied by ffmpeg after the stream
selection process and thus do not influence the latter. If no "-codec"
option is specified for a stream type, ffmpeg will select the default
encoder registered by the output file muxer.
An exception exists for subtitles. If a subtitle encoder is specified
for an output file, the first subtitle stream found of any type, text
or image, will be included. ffmpeg does not validate if the specified
encoder can convert the selected stream or if the converted stream is
acceptable within the output format. This applies generally as well:
when the user sets an encoder manually, the stream selection process
cannot check if the encoded stream can be muxed into the output file.
If it cannot, ffmpeg will abort and all output files will fail to be
processed.
Examples
The following examples illustrate the behavior, quirks and limitations
of ffmpeg's stream selection methods.
They assume the following three input files.
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)
Example: automatic stream selection
ffmpeg -i A.avi -i B.mp4 out1.mkv out2.wav -map 1:a -c:a copy out3.mov
There are three output files specified, and for the first two, no
"-map" options are set, so ffmpeg will select streams for these two
files automatically.
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 "stream 0" from B.mp4, which has the highest
resolution among all the input video streams.For audio, it will select
"stream 3" from B.mp4, since it has the greatest number of channels.For
subtitles, it will select "stream 2" from B.mp4, which is the first
subtitle stream from among A.avi and B.mp4.
out2.wav accepts only audio streams, so only "stream 3" from B.mp4 is
selected.
For out3.mov, since a "-map" option is set, no automatic stream
selection will occur. The "-map 1:a" option will select all audio
streams from the second input B.mp4. No other streams will be included
in this output file.
For the first two outputs, all included streams will be transcoded. The
encoders chosen will be the default ones registered by each output
format, which may not match the codec of the selected input streams.
For the third output, codec option for audio streams has been set to
"copy", so no decoding-filtering-encoding operations will occur, or can
occur. Packets of selected streams shall be conveyed from the input
file and muxed within the output file.
Example: automatic subtitles selection
ffmpeg -i C.mkv out1.mkv -c:s dvdsub -an out2.mkv
Although out1.mkv is a Matroska container file which accepts subtitle
streams, only a video and audio stream shall be selected. The subtitle
stream of 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 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 "-an" disables audio stream selection for
out2.mkv.
Example: unlabeled filtergraph outputs
ffmpeg -i A.avi -i C.mkv -i B.mp4 -filter_complex "overlay" out1.mp4 out2.srt
A filtergraph is setup here using the "-filter_complex" option and
consists of a single video filter. The "overlay" filter requires
exactly two video inputs, but none are specified, so the first two
available video streams are used, those of A.avi and C.mkv. The output
pad of the filter has no label and so is sent to the first output file
out1.mp4. Due to this, automatic selection of the video stream is
skipped, which would have selected the stream in B.mp4. The audio
stream with most channels viz. "stream 3" in B.mp4, is chosen
automatically. No subtitle stream is chosen however, since the MP4
format has no default subtitle encoder registered, and the user hasn't
specified a subtitle encoder.
The 2nd output file, out2.srt, only accepts text-based subtitle
streams. So, even though the first subtitle stream available belongs to
C.mkv, it is image-based and hence skipped. The selected stream,
"stream 2" in B.mp4, is the first text-based subtitle stream.
Example: labeled filtergraph outputs
ffmpeg -i A.avi -i B.mp4 -i C.mkv -filter_complex "[1:v]hue=s=0[outv];overlay;aresample" \
-map '[outv]' -an out1.mp4 \
out2.mkv \
-map '[outv]' -map 1:a:0 out3.mkv
The above command will fail, as the output pad labelled "[outv]" has
been mapped twice. None of the output files shall be processed.
ffmpeg -i A.avi -i B.mp4 -i C.mkv -filter_complex "[1:v]hue=s=0[outv];overlay;aresample" \
-an out1.mp4 \
out2.mkv \
-map 1:a:0 out3.mkv
This command above will also fail as the hue filter output has a label,
"[outv]", and hasn't been mapped anywhere.
The command should be modified as follows,
ffmpeg -i A.avi -i B.mp4 -i C.mkv -filter_complex "[1:v]hue=s=0,split=2[outv1][outv2];overlay;aresample" \
-map '[outv1]' -an out1.mp4 \
out2.mkv \
-map '[outv2]' -map 1:a:0 out3.mkv
The video stream from B.mp4 is sent to the hue filter, whose output is
cloned once using the split filter, and both outputs labelled. Then a
copy each is mapped to the first and third output files.
The overlay filter, requiring two video inputs, uses the first two
unused video streams. Those are the streams from A.avi and C.mkv. The
overlay output isn't labelled, so it is sent to the first output file
out1.mp4, regardless of the presence of the "-map" option.
The aresample filter is sent the first unused audio stream, that of
A.avi. Since this filter output is also unlabelled, it too is mapped to
the first output file. The presence of "-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 out1.mp4.
The video, audio and subtitle streams mapped to "out2.mkv" are entirely
determined by automatic stream selection.
out3.mkv consists of the cloned video output from the hue filter and
the first audio stream from B.mp4.
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'.
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.
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.
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.
ffmpeg -i INPUT -/filter:v filter.script OUTPUT
will load a filtergraph description from the file named filter.script.
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.
A stream specifier is a string generally appended to the option name
and separated from it by a colon. E.g. "-codec:a:1 ac3" contains the
"a:1" stream specifier, which matches the second audio stream.
Therefore, it would select the ac3 codec for the second audio stream.
A stream specifier can match several streams, so that the option is
applied to all of them. E.g. the stream specifier in "-b:a 128k"
matches all audio streams.
An empty stream specifier matches all streams. For example, "-codec
copy" or "-codec: copy" would copy all the streams without reencoding.
Possible forms of stream specifiers are:
stream_index
Matches the stream with this index. E.g. "-threads:1 4" would set
the thread count for the second stream to 4. If stream_index is
used as an additional stream specifier (see below), then it selects
stream number 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.
stream_type[:additional_stream_specifier]
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
additional_stream_specifier is used, then it matches streams which
both have this type and match the additional_stream_specifier.
Otherwise, it matches all streams of the specified type.
g:group_specifier[:additional_stream_specifier]
Matches streams which are in the group with the specifier
group_specifier. if additional_stream_specifier is used, then it
matches streams which both are part of the group and match the
additional_stream_specifier. group_specifier may be one of the
following:
group_index
Match the stream with this group index.
#group_id or i:group_id
Match the stream with this group id.
p:program_id[:additional_stream_specifier]
Matches streams which are in the program with the id program_id. If
additional_stream_specifier is used, then it matches streams which
both are part of the program and match the
additional_stream_specifier.
#stream_id or i:stream_id
Match the stream by stream id (e.g. PID in MPEG-TS container).
m:key[:value]
Matches streams with the metadata tag key having the specified
value. If value is not given, matches streams that contain the
given tag with any value.
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.
Note that in ffmpeg, matching by metadata will only work properly
for input files.
Generic options
These options are shared amongst the ff* tools.
-L Show license.
-h, -?, -help, --help [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.
Possible values of arg are:
long
Print advanced tool options in addition to the basic tool
options.
full
Print complete list of options, including shared and private
options for encoders, decoders, demuxers, muxers, filters, etc.
decoder=decoder_name
Print detailed information about the decoder named
decoder_name. Use the -decoders option to get a list of all
decoders.
encoder=encoder_name
Print detailed information about the encoder named
encoder_name. Use the -encoders option to get a list of all
encoders.
demuxer=demuxer_name
Print detailed information about the demuxer named
demuxer_name. Use the -formats option to get a list of all
demuxers and muxers.
muxer=muxer_name
Print detailed information about the muxer named muxer_name.
Use the -formats option to get a list of all muxers and
demuxers.
filter=filter_name
Print detailed information about the filter named filter_name.
Use the -filters option to get a list of all filters.
bsf=bitstream_filter_name
Print detailed information about the bitstream filter named
bitstream_filter_name. Use the -bsfs option to get a list of
all bitstream filters.
protocol=protocol_name
Print detailed information about the protocol named
protocol_name. Use the -protocols option to get a list of all
protocols.
-version
Show version.
-buildconf
Show the build configuration, one option per line.
-formats
Show available formats (including devices).
-demuxers
Show available demuxers.
-muxers
Show available muxers.
-devices
Show available devices.
-codecs
Show all codecs known to libavcodec.
Note that the term 'codec' is used throughout this documentation as
a shortcut for what is more correctly called a media bitstream
format.
-decoders
Show available decoders.
-encoders
Show all available encoders.
-bsfs
Show available bitstream filters.
-protocols
Show available protocols.
-filters
Show available libavfilter filters.
-pix_fmts
Show available pixel formats.
-sample_fmts
Show available sample formats.
-layouts
Show channel names and standard channel layouts.
-dispositions
Show stream dispositions.
-colors
Show recognized color names.
-sources device[,opt1=val1[,opt2=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.
ffmpeg -sources pulse,server=192.168.0.4
-sinks device[,opt1=val1[,opt2=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.
ffmpeg -sinks pulse,server=192.168.0.4
-loglevel [flags+]loglevel | -v [flags+]loglevel
Set logging level and flags used by the library.
The optional flags prefix can consist of the following values:
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.
level
Indicates that log output should add a "[level]" prefix to each
message line. This can be used as an alternative to log
coloring, e.g. when dumping the log to file.
Flags can also be used alone by adding a '+'/'-' prefix to
set/reset a single flag without affecting other flags or changing
loglevel. When setting both flags and loglevel, a '+' separator is
expected between the last flags value and before loglevel.
loglevel is a string or a number containing one of the following
values:
quiet, -8
Show nothing at all; be silent.
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.
fatal, 8
Only show fatal errors. These are errors after which the
process absolutely cannot continue.
error, 16
Show all errors, including ones which can be recovered from.
warning, 24
Show all warnings and errors. Any message related to possibly
incorrect or unexpected events will be shown.
info, 32
Show informative messages during processing. This is in
addition to warnings and errors. This is the default value.
verbose, 40
Same as "info", except more verbose.
debug, 48
Show everything, including debugging information.
trace, 56
For example to enable repeated log output, add the "level" prefix,
and set loglevel to "verbose":
ffmpeg -loglevel repeat+level+verbose -i input output
Another example that enables repeated log output without affecting
current state of "level" prefix flag or loglevel:
ffmpeg [...] -loglevel +repeat
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
AV_LOG_FORCE_NOCOLOR, or can be forced setting the environment
variable AV_LOG_FORCE_COLOR.
-report
Dump full command line and log output to a file named
"program-YYYYMMDD-HHMMSS.log" in the current directory. This file
can be useful for bug reports. It also implies "-loglevel debug".
Setting the environment variable 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 ``Quoting and escaping'' section in the ffmpeg-utils manual).
The following options are recognized:
file
set the file name to use for the report; %p is expanded to the
name of the program, %t is expanded to a timestamp, "%%" is
expanded to a plain "%"
level
set the log verbosity level using a numerical value (see
"-loglevel").
For example, to output a report to a file named ffreport.log using
a log level of 32 (alias for log level "info"):
FFREPORT=file=ffreport.log:level=32 ffmpeg -i input output
Errors in parsing the environment variable are not fatal, and will
not appear in the report.
-hide_banner
Suppress printing banner.
All FFmpeg tools will normally show a copyright notice, build
options and library versions. This option can be used to suppress
printing this information.
-cpuflags flags (global)
Allows setting and clearing cpu flags. This option is intended for
testing. Do not use it unless you know what you're doing.
ffmpeg -cpuflags -sse+mmx ...
ffmpeg -cpuflags mmx ...
ffmpeg -cpuflags 0 ...
Possible flags for this option are:
x86
mmx
mmxext
sse
sse2
sse2slow
sse3
sse3slow
ssse3
atom
sse4.1
sse4.2
avx
avx2
xop
fma3
fma4
3dnow
3dnowext
bmi1
bmi2
cmov
ARM
armv5te
armv6
armv6t2
vfp
vfpv3
neon
setend
AArch64
armv8
vfp
neon
PowerPC
altivec
Specific Processors
pentium2
pentium3
pentium4
k6
k62
athlon
athlonxp
k8
-cpucount count (global)
Override detection of CPU count. This option is intended for
testing. Do not use it unless you know what you're doing.
ffmpeg -cpucount 2
-max_alloc bytes
Set the maximum size limit for allocating a block on the heap by
ffmpeg's family of malloc functions. Exercise extreme caution when
using this option. Don't use if you do not understand the full
consequence of doing so. Default is INT_MAX.
AVOptions
These options are provided directly by the libavformat, libavdevice and
libavcodec libraries. To see the list of available AVOptions, use the
-help option. They are separated into two categories:
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.
private
These options are specific to the given container, device or codec.
Private options are listed under their corresponding
containers/devices/codecs.
For example to write an ID3v2.3 header instead of a default ID3v2.4 to
an MP3 file, use the id3v2_version private option of the MP3 muxer:
ffmpeg -i input.flac -id3v2_version 3 out.mp3
All codec AVOptions are per-stream, and thus a stream specifier should
be attached to them:
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
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.
Note: the -nooption syntax cannot be used for boolean AVOptions, use
-option 0/-option 1.
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.
Main options
-f fmt (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.
-i url (input)
input file url
-y (global)
Overwrite output files without asking.
-n (global)
Do not overwrite output files, and exit immediately if a specified
output file already exists.
-stream_loop number (input)
Set number of times input stream shall be looped. Loop 0 means no
loop, loop -1 means infinite loop.
-recast_media (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.
-c[:stream_specifier] codec (input/output,per-stream)
-codec[:stream_specifier] codec (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. codec is
the name of a decoder/encoder or a special value "copy" (output
only) to indicate that the stream is not to be re-encoded.
For example
ffmpeg -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT
encodes all video streams with libx264 and copies all audio
streams.
For each stream, the last matching "c" option is applied, so
ffmpeg -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT
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.
-t duration (input/output)
When used as an input option (before "-i"), limit the duration of
data read from the input file.
When used as an output option (before an output url), stop writing
the output after its duration reaches duration.
duration must be a time duration specification, see the Time
duration section in the ffmpeg-utils(1) manual.
-to and -t are mutually exclusive and -t has priority.
-to position (input/output)
Stop writing the output or reading the input at position. position
must be a time duration specification, see the Time duration
section in the ffmpeg-utils(1) manual.
-to and -t are mutually exclusive and -t has priority.
-fs limit_size (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.
-ss position (input/output)
When used as an input option (before "-i"), seeks in this input
file to position. Note that in most formats it is not possible to
seek exactly, so ffmpeg will seek to the closest seek point before
position. When transcoding and -accurate_seek is enabled (the
default), this extra segment between the seek point and position
will be decoded and discarded. When doing stream copy or when
-noaccurate_seek is used, it will be preserved.
When used as an output option (before an output url), decodes but
discards input until the timestamps reach position.
position must be a time duration specification, see the Time
duration section in the ffmpeg-utils(1) manual.
-sseof position (input)
Like the "-ss" option but relative to the "end of file". That is
negative values are earlier in the file, 0 is at EOF.
-isync input_index (input)
Assign an input as a sync source.
This will take the difference between the start times of the target
and reference inputs and offset the timestamps of the target file
by that difference. The source timestamps of the two inputs should
derive from the same clock source for expected results. If "copyts"
is set then "start_at_zero" must also be set. If either of the
inputs has no starting timestamp then no sync adjustment is made.
Acceptable values are those that refer to a valid ffmpeg input
index. If the sync reference is the target index itself or -1, then
no adjustment is made to target timestamps. A sync reference may
not itself be synced to any other input.
Default value is -1.
-itsoffset offset (input)
Set the input time offset.
offset must be a time duration specification, see the Time duration
section in the ffmpeg-utils(1) manual.
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 offset.
-itsscale scale (input,per-stream)
Rescale input timestamps. scale should be a floating point number.
-timestamp date (output)
Set the recording timestamp in the container.
date must be a date specification, see the Date section in the
ffmpeg-utils(1) manual.
-metadata[:metadata_specifier] key=value (output,per-metadata)
Set a metadata key/value pair.
An optional metadata_specifier may be given to set metadata on
streams, chapters or programs. See "-map_metadata" documentation
for details.
This option overrides metadata set with "-map_metadata". It is also
possible to delete metadata by using an empty value.
For example, for setting the title in the output file:
ffmpeg -i in.avi -metadata title="my title" out.flv
To set the language of the first audio stream:
ffmpeg -i INPUT -metadata:s:a:0 language=eng OUTPUT
-disposition[:stream_specifier] value (output,per-stream)
Sets the disposition for a stream.
By default, the disposition is copied from the input stream, unless
the output stream this option applies to is fed by a complex
filtergraph - in that case the disposition is unset by default.
value is a sequence of items separated by '+' or '-'. The first
item may also be prefixed with '+' or '-', in which case this
option modifies the default value. Otherwise (the first item is not
prefixed) this options overrides the default value. A '+' prefix
adds the given disposition, '-' removes it. It is also possible to
clear the disposition by setting it to 0.
If no "-disposition" options were specified for an output file,
ffmpeg will automatically set the 'default' disposition on the
first stream of each type, when there are multiple streams of this
type in the output file and no stream of that type is already
marked as default.
The "-dispositions" option lists the known dispositions.
For example, to make the second audio stream the default stream:
ffmpeg -i in.mkv -c copy -disposition:a:1 default out.mkv
To make the second subtitle stream the default stream and remove
the default disposition from the first subtitle stream:
ffmpeg -i in.mkv -c copy -disposition:s:0 0 -disposition:s:1 default out.mkv
To add an embedded cover/thumbnail:
ffmpeg -i in.mp4 -i IMAGE -map 0 -map 1 -c copy -c:v:1 png -disposition:v:1 attached_pic out.mp4
Not all muxers support embedded thumbnails, and those who do, only
support a few formats, like JPEG or PNG.
-program
[title=title:][program_num=program_num:]st=stream[:st=stream...]
(output)
Creates a program with the specified title, program_num and adds
the specified stream(s) to it.
-stream_group
type=type:st=stream[:st=stream][:stg=stream_group][:id=stream_group_id...]
(output)
Creates a stream group of the specified type, stream_group_id and
adds the specified stream(s) and/or previously defined
stream_group(s) to it.
type can be one of the following:
iamf_audio_element
Groups streams that belong to the same IAMF Audio Element
For this group type, the following options are available
audio_element_type
The Audio Element type. The following values are supported:
channel
Scalable channel audio representation
scene
Ambisonics representation
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
parameter_id
An identifier parameters blocks in frames may refer to
dmixp_mode
A pre-defined combination of demixing parameters
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
parameter_id
An identifier parameters blocks in frames may refer to
layer
A layer defining a Channel Layout in the Audio Element.
This option must be separated from the rest with a ','.
Several ',' separated entries can be defined, and at least
one must be set.
It takes the following ":"-separated key=value options
ch_layout
The layer's channel layout
flags
The following flags are available:
recon_gain
Wether to signal if recon_gain is present as
metadata in parameter blocks within frames
output_gain
output_gain_flags
Which channels output_gain applies to. The following
flags are available:
FL
FR
BL
BR
TFL
TFR
ambisonics_mode
The ambisonics mode. This has no effect if
audio_element_type is set to channel.
The following values are supported:
mono
Each ambisonics channel is coded as an individual
mono stream in the group
default_w
Default weight value
iamf_mix_presentation
Groups streams that belong to all IAMF Audio Element the same
IAMF Mix Presentation references
For this group type, the following options are available
submix
A sub-mix within the Mix Presentation. This option must be
separated from the rest with a ','. Several ',' separated
entries can be defined, and at least one must be set.
It takes the following ":"-separated key=value options
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
parameter_rate
The sample rate duration fields in parameters blocks in
frames that refer to this parameter_id are expressed as
default_mix_gain
Default mix gain value to apply when there are no
parameter blocks sharing the same parameter_id for a
given frame
element
References an Audio Element used in this Mix
Presentation to generate the final output audio signal
for playback. This option must be separated from the
rest with a '|'. Several '|' separated entries can be
defined, and at least one must be set.
It takes the following ":"-separated key=value options:
stg The stream_group_id for an Audio Element which this
sub-mix refers to
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
parameter_rate
The sample rate duration fields in parameters
blocks in frames that refer to this parameter_id
are expressed as
default_mix_gain
Default mix gain value to apply when there are no
parameter blocks sharing the same parameter_id for
a given frame
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
annotations
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 audio_element_type is
set to channel.
The following values are supported:
stereo
binaural
layout
Specifies the layouts for this sub-mix on which the
loudness information was measured. This option must be
separated from the rest with a '|'. Several '|'
separated entries can be defined, and at least one must
be set.
It takes the following ":"-separated key=value options:
layout_type
loudspeakers
The layout follows the loudspeaker sound system
convention of ITU-2051-3.
binaural
The layout is binaural.
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 layout_type is set to binaural.
integrated_loudness
The program integrated loudness information, as
defined in ITU-1770-4.
digital_peak
The digital (sampled) peak value of the audio
signal, as defined in ITU-1770-4.
true_peak
The true peak of the audio signal, as defined in
ITU-1770-4.
dialog_anchored_loudness
The Dialogue loudness information, as defined in
ITU-1770-4.
album_anchored_loudness
The Album loudness information, as defined in
ITU-1770-4.
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 annotationss
-target type (output)
Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50"). type
may be prefixed with "pal-", "ntsc-" or "film-" to use the
corresponding standard. All the format options (bitrate, codecs,
buffer sizes) are then set automatically. You can just type:
ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
Nevertheless you can specify additional options as long as you know
they do not conflict with the standard, as in:
ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
The parameters set for each target are as follows.
VCD
<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
SVCD
<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
DVD
<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
DV
<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
The "dv50" target is identical to the "dv" target except that the
pixel format set is "yuv422p" for all three standards.
Any user-set value for a parameter above will override the target
preset value. In that case, the output may not comply with the
target standard.
-dn (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 "-discard" option to disable streams individually.
As an output option, disables data recording i.e. automatic
selection or mapping of any data stream. For full manual control
see the "-map" option.
-dframes number (output)
Set the number of data frames to output. This is an obsolete alias
for "-frames:d", which you should use instead.
-frames[:stream_specifier] framecount (output,per-stream)
Stop writing to the stream after framecount frames.
-q[:stream_specifier] q (output,per-stream)
-qscale[:stream_specifier] q (output,per-stream)
Use fixed quality scale (VBR). The meaning of q/qscale is codec-
dependent. If qscale is used without a 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.
-filter[:stream_specifier] filtergraph (output,per-stream)
Create the filtergraph specified by filtergraph and use it to
filter the stream.
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 "in", and the output to the label "out".
See the ffmpeg-filters manual for more information about the
filtergraph syntax.
See the -filter_complex option if you want to create filtergraphs
with multiple inputs and/or outputs.
-reinit_filter[:stream_specifier] integer (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 "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.
-filter_threads nb_threads (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.
-pre[:stream_specifier] preset_name (output,per-stream)
Specify the preset for matching stream(s).
-stats (global)
Print encoding progress/statistics. It is on by default, to
explicitly disable it you need to specify "-nostats".
-stats_period time (global)
Set period at which encoding progress/statistics are updated.
Default is 0.5 seconds.
-progress url (global)
Send program-friendly progress information to url.
Progress information is written periodically and at the end of the
encoding process. It is made of "key=value" lines. key consists of
only alphanumeric characters. The last key of a sequence of
progress information is always "progress".
The update period is set using "-stats_period".
-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 "-nostdin".
Disabling interaction on standard input is useful, for example, if
ffmpeg is in the background process group. Roughly the same result
can be achieved with "ffmpeg ... < /dev/null" but it requires a
shell.
-debug_ts (global)
Print timestamp/latency information. It is off by default. This
option is mostly useful for testing and debugging purposes, and the
output format may change from one version to another, so it should
not be employed by portable scripts.
See also the option "-fdebug ts".
-attach filename (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 "-map" or automatic
mappings).
Note that for Matroska you also have to set the mimetype metadata
tag:
ffmpeg -i INPUT -attach DejaVuSans.ttf -metadata:s:2 mimetype=application/x-truetype-font out.mkv
(assuming that the attachment stream will be third in the output
file).
-dump_attachment[:stream_specifier] filename (input,per-stream)
Extract the matching attachment stream into a file named filename.
If filename is empty, then the value of the "filename" metadata tag
will be used.
E.g. to extract the first attachment to a file named 'out.ttf':
ffmpeg -dump_attachment:t:0 out.ttf -i INPUT
To extract all attachments to files determined by the "filename"
tag:
ffmpeg -dump_attachment:t "" -i INPUT
Technical note -- attachments are implemented as codec extradata,
so this option can actually be used to extract extradata from any
stream, not just attachments.
Video Options
-vframes number (output)
Set the number of video frames to output. This is an obsolete alias
for "-frames:v", which you should use instead.
-r[:stream_specifier] fps (input/output,per-stream)
Set frame rate (Hz value, fraction or abbreviation).
As an input option, ignore any timestamps stored in the file and
instead generate timestamps assuming constant frame rate fps. This
is not the same as the -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 -framerate instead of the
input option -r.
As an output option:
video encoding
Duplicate or drop frames right before encoding them to achieve
constant output frame rate fps.
video streamcopy
Indicate to the muxer that fps is the stream frame rate. No
data is dropped or duplicated in this case. This may produce
invalid files if fps does not match the actual stream frame
rate as determined by packet timestamps. See also the "setts"
bitstream filter.
-fpsmax[:stream_specifier] fps (output,per-stream)
Set maximum frame rate (Hz value, fraction or abbreviation).
Clamps output frame rate when output framerate is auto-set and is
higher than this value. Useful in batch processing or when input
framerate is wrongly detected as very high. It cannot be set
together with "-r". It is ignored during streamcopy.
-s[:stream_specifier] size (input/output,per-stream)
Set frame size.
As an input option, this is a shortcut for the video_size private
option, recognized by some demuxers for which the frame size is
either not stored in the file or is configurable -- e.g. raw video
or video grabbers.
As an output option, this inserts the "scale" video filter to the
end of the corresponding filtergraph. Please use the "scale" filter
directly to insert it at the beginning or some other place.
The format is wxh (default - same as source).
-aspect[:stream_specifier] aspect (output,per-stream)
Set the video display aspect ratio specified by aspect.
aspect can be a floating point number string, or a string of the
form num:den, where num and den are the numerator and denominator
of the aspect ratio. For example "4:3", "16:9", "1.3333", and
"1.7777" are valid argument values.
If used together with -vcodec copy, it will affect the aspect ratio
stored at container level, but not the aspect ratio stored in
encoded frames, if it exists.
-display_rotation[:stream_specifier] rotation (input,per-stream)
Set video rotation metadata.
rotation is a decimal number specifying the amount in degree by
which the video should be rotated counter-clockwise before being
displayed.
This option overrides the rotation/display transform metadata
stored in the file, if any. When the video is being transcoded
(rather than copied) and "-autorotate" is enabled, the video will
be rotated at the filtering stage. Otherwise, the metadata will be
written into the output file if the muxer supports it.
If the "-display_hflip" and/or "-display_vflip" options are given,
they are applied after the rotation specified by this option.
-display_hflip[:stream_specifier] (input,per-stream)
Set whether on display the image should be horizontally flipped.
See the "-display_rotation" option for more details.
-display_vflip[:stream_specifier] (input,per-stream)
Set whether on display the image should be vertically flipped.
See the "-display_rotation" option for more details.
-vn (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 "-discard" option to disable streams individually.
As an output option, disables video recording i.e. automatic
selection or mapping of any video stream. For full manual control
see the "-map" option.
-vcodec codec (output)
Set the video codec. This is an alias for "-codec:v".
-pass[:stream_specifier] n (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:
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
-passlogfile[:stream_specifier] prefix (output,per-stream)
Set two-pass log file name prefix to prefix, the default file name
prefix is ``ffmpeg2pass''. The complete file name will be
PREFIX-N.log, where N is a number specific to the output stream
-vf filtergraph (output)
Create the filtergraph specified by filtergraph and use it to
filter the stream.
This is an alias for "-filter:v", see the -filter option.
-autorotate
Automatically rotate the video according to file metadata. Enabled
by default, use -noautorotate to disable it.
-autoscale
Automatically scale the video according to the resolution of first
frame. Enabled by default, use -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.
Advanced Video options
-pix_fmt[:stream_specifier] format (input/output,per-stream)
Set pixel format. Use "-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 pix_fmt is prefixed by a "+", ffmpeg will exit
with an error if the requested pixel format can not be selected,
and automatic conversions inside filtergraphs are disabled. If
pix_fmt is a single "+", ffmpeg selects the same pixel format as
the input (or graph output) and automatic conversions are disabled.
-sws_flags flags (input/output)
Set default flags for the libswscale library. These flags are used
by automatically inserted "scale" filters and those within simple
filtergraphs, if not overridden within the filtergraph definition.
See the ffmpeg-scaler manual for a list of scaler options.
-rc_override[:stream_specifier] override (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.
-psnr
Calculate PSNR of compressed frames. This option is deprecated,
pass the PSNR flag to the encoder instead, using "-flags +psnr".
-vstats
Dump video coding statistics to vstats_HHMMSS.log. See the vstats
file format section for the format description.
-vstats_file file
Dump video coding statistics to file. See the vstats file format
section for the format description.
-vstats_version file
Specify which version of the vstats format to use. Default is 2.
See the vstats file format section for the format description.
-vtag fourcc/tag (output)
Force video tag/fourcc. This is an alias for "-tag:v".
-force_key_frames[:stream_specifier] time[,time...] (output,per-stream)
-force_key_frames[:stream_specifier] expr:expr (output,per-stream)
-force_key_frames[:stream_specifier] source (output,per-stream)
force_key_frames can take arguments of the following form:
time[,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
"-enc_time_base".
If one of the times is ""chapters"[delta]", it is expanded into
the time of the beginning of all chapters in the file, shifted
by delta, expressed as a time in seconds. This option can be
useful to ensure that a seek point is present at a chapter mark
or any other designated place in the output file.
For example, to insert a key frame at 5 minutes, plus key
frames 0.1 second before the beginning of every chapter:
-force_key_frames 0:05:00,chapters-0.1
expr:expr
If the argument is prefixed with "expr:", the string expr is
interpreted like an expression and is evaluated for each frame.
A key frame is forced in case the evaluation is non-zero.
The expression in expr can contain the following constants:
n the number of current processed frame, starting from 0
n_forced
the number of forced frames
prev_forced_n
the number of the previous forced frame, it is "NAN" when
no keyframe was forced yet
prev_forced_t
the time of the previous forced frame, it is "NAN" when no
keyframe was forced yet
t the time of the current processed frame
For example to force a key frame every 5 seconds, you can
specify:
-force_key_frames expr:gte(t,n_forced*5)
To force a key frame 5 seconds after the time of the last
forced one, starting from second 13:
-force_key_frames expr:if(isnan(prev_forced_t),gte(t,13),gte(t,prev_forced_t+5))
source
If the argument is "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.
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.
-copyinkf[:stream_specifier] (output,per-stream)
When doing stream copy, copy also non-key frames found at the
beginning.
-init_hw_device type[=name][:device[,key=value...]]
Initialise a new hardware device of type type called name, using
the given device parameters. If no name is specified it will
receive a default name of the form "type%d".
The meaning of device and the following arguments depends on the
device type:
cuda
device is the number of the CUDA device.
The following options are recognized:
primary_ctx
If set to 1, uses the primary device context instead of
creating a new one.
Examples:
-init_hw_device cuda:1
Choose the second device on the system.
-init_hw_device cuda:0,primary_ctx=1
Choose the first device and use the primary device context.
dxva2
device is the number of the Direct3D 9 display adapter.
d3d11va
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 vendor_id.
Examples:
-init_hw_device d3d11va
Create a d3d11va device on the default Direct3D 11 display
adapter.
-init_hw_device d3d11va:1
Create a d3d11va device on the Direct3D 11 display adapter
specified by index 1.
-init_hw_device d3d11va:,vendor_id=0x8086
Create a d3d11va device on the first Direct3D 11 display
adapter whose hardware VendorId is 0x8086.
vaapi
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 ($DISPLAY) and then the first DRM
render node (/dev/dri/renderD128), or the default DirectX
adapter on Windows.
The following options are recognized:
kernel_driver
When device is not specified, use this option to specify
the name of the kernel driver associated with the desired
device. This option is available only when the hardware
acceleration method drm and vaapi are enabled.
Examples:
-init_hw_device vaapi
Create a vaapi device on the default device.
-init_hw_device vaapi:/dev/dri/renderD129
Create a vaapi device on DRM render node
/dev/dri/renderD129.
-init_hw_device vaapi:1
Create a vaapi device on DirectX adapter 1.
-init_hw_device vaapi:,kernel_driver=i915
Create a vaapi device on a device associated with kernel
driver i915.
vdpau
device is an X11 display name. If not specified, it will
attempt to open the default X11 display ($DISPLAY).
qsv device selects a value in MFX_IMPL_*. Allowed values are:
auto
sw
hw
auto_any
hw_any
hw2
hw3
hw4
If not specified, auto_any is used. (Note that it may be
easier to achieve the desired result for QSV by creating the
platform-appropriate subdevice (dxva2 or d3d11va or vaapi) and
then deriving a QSV device from that.)
The following options are recognized:
child_device
Specify a DRM render node on Linux or DirectX adapter on
Windows.
child_device_type
Choose platform-appropriate subdevice type. On Windows
d3d11va is used as default subdevice type when
"--enable-libvpl" is specified at configuration time, dxva2
is used as default subdevice type when "--enable-libmfx" is
specified at configuration time. On Linux user can use
vaapi only as subdevice type.
Examples:
-init_hw_device qsv:hw,child_device=/dev/dri/renderD129
Create a QSV device with MFX_IMPL_HARDWARE on DRM render
node /dev/dri/renderD129.
-init_hw_device qsv:hw,child_device=1
Create a QSV device with MFX_IMPL_HARDWARE on DirectX
adapter 1.
-init_hw_device qsv:hw,child_device_type=d3d11va
Choose the GPU subdevice with type d3d11va and create QSV
device with MFX_IMPL_HARDWARE.
-init_hw_device qsv:hw,child_device_type=dxva2
Choose the GPU subdevice with type dxva2 and create QSV
device with MFX_IMPL_HARDWARE.
-init_hw_device qsv:hw,child_device=1,child_device_type=d3d11va
Create a QSV device with MFX_IMPL_HARDWARE on DirectX
adapter 1 with subdevice type d3d11va.
-init_hw_device vaapi=va:/dev/dri/renderD129 -init_hw_device
qsv=hw1@va
Create a VAAPI device called va on /dev/dri/renderD129,
then derive a QSV device called hw1 from device va.
opencl
device selects the platform and device as
platform_index.device_index.
The set of devices can also be filtered using the key-value
pairs to find only devices matching particular platform or
device strings.
The strings usable as filters are:
platform_profile
platform_version
platform_name
platform_vendor
platform_extensions
device_name
device_vendor
driver_version
device_version
device_profile
device_extensions
device_type
The indices and filters must together uniquely select a device.
Examples:
-init_hw_device opencl:0.1
Choose the second device on the first platform.
-init_hw_device opencl:,device_name=Foo9000
Choose the device with a name containing the string
Foo9000.
-init_hw_device
opencl:1,device_type=gpu,device_extensions=cl_khr_fp16
Choose the GPU device on the second platform supporting the
cl_khr_fp16 extension.
vulkan
If device is an integer, it selects the device by its index in
a system-dependent list of devices. If device is any other
string, it selects the first device with a name containing that
string as a substring.
The following options are recognized:
debug
If set to 1, enables the validation layer, if installed.
linear_images
If set to 1, images allocated by the hwcontext will be
linear and locally mappable.
instance_extensions
A plus separated list of additional instance extensions to
enable.
device_extensions
A plus separated list of additional device extensions to
enable.
Examples:
-init_hw_device vulkan:1
Choose the second device on the system.
-init_hw_device vulkan:RADV
Choose the first device with a name containing the string
RADV.
-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.
-init_hw_device type[=name]@source
Initialise a new hardware device of type type called name, deriving
it from the existing device with the name source.
-init_hw_device list
List all hardware device types supported in this build of ffmpeg.
-filter_hw_device name
Pass the hardware device called name to all filters in any filter
graph. This can be used to set the device to upload to with the
"hwupload" filter, or the device to map to with the "hwmap" filter.
Other filters may also make use of this parameter when they require
a hardware device. Note that this is typically only required when
the input is not already in hardware frames - when it is, filters
will derive the device they require from the context of the frames
they receive as input.
This is a global setting, so all filters will receive the same
device.
-hwaccel[:stream_specifier] hwaccel (input,per-stream)
Use hardware acceleration to decode the matching stream(s). The
allowed values of hwaccel are:
none
Do not use any hardware acceleration (the default).
auto
Automatically select the hardware acceleration method.
vdpau
Use VDPAU (Video Decode and Presentation API for Unix) hardware
acceleration.
dxva2
Use DXVA2 (DirectX Video Acceleration) hardware acceleration.
d3d11va
Use D3D11VA (DirectX Video Acceleration) hardware acceleration.
vaapi
Use VAAPI (Video Acceleration API) hardware acceleration.
qsv Use the Intel QuickSync Video acceleration for video
transcoding.
Unlike most other values, this option does not enable
accelerated decoding (that is used automatically whenever a qsv
decoder is selected), but accelerated transcoding, without
copying the frames into the system memory.
For it to work, both the decoder and the encoder must support
QSV acceleration and no filters must be used.
This option has no effect if the selected hwaccel is not available
or not supported by the chosen decoder.
Note that most acceleration methods are intended for playback and
will not be faster than software decoding on modern CPUs.
Additionally, 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.
-hwaccel_device[:stream_specifier] hwaccel_device (input,per-stream)
Select a device to use for hardware acceleration.
This option only makes sense when the -hwaccel option is also
specified. It can either refer to an existing device created with
-init_hw_device by name, or it can create a new device as if
-init_hw_device type:hwaccel_device were called immediately before.
-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.
-fix_sub_duration_heartbeat[:stream_specifier]
Set a specific output video stream as the heartbeat stream
according to which to split and push through currently in-progress
subtitle upon receipt of a random access packet.
This lowers the latency of subtitles for which the end packet or
the following subtitle has not yet been received. As a drawback,
this will most likely lead to duplication of subtitle events in
order to cover the full duration, so when dealing with use cases
where latency of when the subtitle event is passed on to output is
not relevant this option should not be utilized.
Requires -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.
Audio Options
-aframes number (output)
Set the number of audio frames to output. This is an obsolete alias
for "-frames:a", which you should use instead.
-ar[:stream_specifier] freq (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.
-aq q (output)
Set the audio quality (codec-specific, VBR). This is an alias for
-q:a.
-ac[:stream_specifier] channels (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.
-an (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 "-discard" option to disable streams individually.
As an output option, disables audio recording i.e. automatic
selection or mapping of any audio stream. For full manual control
see the "-map" option.
-acodec codec (input/output)
Set the audio codec. This is an alias for "-codec:a".
-sample_fmt[:stream_specifier] sample_fmt (output,per-stream)
Set the audio sample format. Use "-sample_fmts" to get a list of
supported sample formats.
-af filtergraph (output)
Create the filtergraph specified by filtergraph and use it to
filter the stream.
This is an alias for "-filter:a", see the -filter option.
Advanced Audio options
-atag fourcc/tag (output)
Force audio tag/fourcc. This is an alias for "-tag:a".
-guess_layout_max channels (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 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.
Subtitle options
-scodec codec (input/output)
Set the subtitle codec. This is an alias for "-codec:s".
-sn (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 "-discard" option to disable streams individually.
As an output option, disables subtitle recording i.e. automatic
selection or mapping of any subtitle stream. For full manual
control see the "-map" option.
Advanced Subtitle options
-fix_sub_duration
Fix subtitles durations. For each subtitle, wait for the next
packet in the same stream and adjust the duration of the first to
avoid overlap. This is necessary with some subtitles codecs,
especially DVB subtitles, because the duration in the original
packet is only a rough estimate and the end is actually marked by
an empty subtitle frame. Failing to use this option when necessary
can result in exaggerated durations or muxing failures due to non-
monotonic timestamps.
Note that this option will delay the output of all data until the
next subtitle packet is decoded: it may increase memory consumption
and latency a lot.
-canvas_size size
Set the size of the canvas used to render subtitles.
Advanced options
-map [-]input_file_id[:stream_specifier][?] | [linklabel] (output)
Create one or more streams in the output file. This option has two
forms for specifying the data source(s): the first selects one or
more streams from some input file (specified with "-i"), the second
takes an output from some complex filtergraph (specified with
"-filter_complex").
In the first form, an output stream is created for every stream
from the input file with the index input_file_id. If
stream_specifier is given, only those streams that match the
specifier are used (see the Stream specifiers section for the
stream_specifier syntax).
A "-" character before the stream identifier creates a "negative"
mapping. It disables matching streams from already created
mappings.
A trailing "?" after the stream index will allow the map to be
optional: if the map matches no streams the map will be ignored
instead of failing. Note the map will still fail if an invalid
input file index is used; such as if the map refers to a non-
existent input.
An alternative [linklabel] form will map outputs from complex
filter graphs (see the -filter_complex option) to the output file.
linklabel must correspond to a defined output link label in the
graph.
This option may be specified multiple times, each adding more
streams to the output file. Any given input stream may also be
mapped any number of times as a source for different output
streams, e.g. in order to use different encoding options and/or
filters. The streams are created in the output in the same order in
which the "-map" options are given on the commandline.
Using this option disables the default mappings for this output
file.
Examples:
map everything
To map ALL streams from the first input file to output
ffmpeg -i INPUT -map 0 output
select specific stream
If you have two audio streams in the first input file, these
streams are identified by 0:0 and 0:1. You can use "-map" to
select which streams to place in an output file. For example:
ffmpeg -i INPUT -map 0:1 out.wav
will map the second input stream in INPUT to the (single)
output stream in out.wav.
create multiple streams
To select the stream with index 2 from input file a.mov
(specified by the identifier 0:2), and stream with index 6 from
input b.mov (specified by the identifier 1:6), and copy them to
the output file out.mov:
ffmpeg -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov
create multiple streams 2
To select all video and the third audio stream from an input
file:
ffmpeg -i INPUT -map 0:v -map 0:a:2 OUTPUT
negative map
To map all the streams except the second audio, use negative
mappings
ffmpeg -i INPUT -map 0 -map -0:a:1 OUTPUT
optional map
To map the video and audio streams from the first input, and
using the trailing "?", ignore the audio mapping if no audio
streams exist in the first input:
ffmpeg -i INPUT -map 0:v -map 0:a? OUTPUT
map by language
To pick the English audio stream:
ffmpeg -i INPUT -map 0:m:language:eng OUTPUT
-ignore_unknown
Ignore input streams with unknown type instead of failing if
copying such streams is attempted.
-copy_unknown
Allow input streams with unknown type to be copied instead of
failing if copying such streams is attempted.
-map_channel
[input_file_id.stream_specifier.channel_id|-1][?][:output_file_id.stream_specifier]
This option is deprecated and will be removed. It can be replaced
by the pan filter. In some cases it may be easier to use some
combination of the channelsplit, channelmap, or amerge filters.
Map an audio channel from a given input to an output. If
output_file_id.stream_specifier is not set, the audio channel will
be mapped on all the audio streams.
Using "-1" instead of input_file_id.stream_specifier.channel_id
will map a muted channel.
A trailing "?" will allow the map_channel to be optional: if the
map_channel matches no channel the map_channel will be ignored
instead of failing.
For example, assuming INPUT is a stereo audio file, you can switch
the two audio channels with the following command:
ffmpeg -i INPUT -map_channel 0.0.1 -map_channel 0.0.0 OUTPUT
If you want to mute the first channel and keep the second:
ffmpeg -i INPUT -map_channel -1 -map_channel 0.0.1 OUTPUT
The order of the "-map_channel" option specifies the order of the
channels in the output stream. The output channel layout is guessed
from the number of channels mapped (mono if one "-map_channel",
stereo if two, etc.). Using "-ac" in combination of "-map_channel"
makes the channel gain levels to be updated if input and output
channel layouts don't match (for instance two "-map_channel"
options and "-ac 6").
You can also extract each channel of an input to specific outputs;
the following command extracts two channels of the INPUT audio
stream (file 0, stream 0) to the respective OUTPUT_CH0 and
OUTPUT_CH1 outputs:
ffmpeg -i INPUT -map_channel 0.0.0 OUTPUT_CH0 -map_channel 0.0.1 OUTPUT_CH1
The following example splits the channels of a stereo input into
two separate streams, which are put into the same output file:
ffmpeg -i stereo.wav -map 0:0 -map 0:0 -map_channel 0.0.0:0.0 -map_channel 0.0.1:0.1 -y out.ogg
Note that currently each output stream can only contain channels
from a single input stream; you can't for example use
"-map_channel" to pick multiple input audio channels contained in
different streams (from the same or different files) and merge them
into a single output stream. It is therefore not currently
possible, for example, to turn two separate mono streams into a
single stereo stream. However splitting a stereo stream into two
single channel mono streams is possible.
If you need this feature, a possible workaround is to use the
amerge filter. For example, if you need to merge a media (here
input.mkv) with 2 mono audio streams into one single stereo channel
audio stream (and keep the video stream), you can use the following
command:
ffmpeg -i input.mkv -filter_complex "[0:1] [0:2] amerge" -c:a pcm_s16le -c:v copy output.mkv
To map the first two audio channels from the first input, and using
the trailing "?", ignore the audio channel mapping if the first
input is mono instead of stereo:
ffmpeg -i INPUT -map_channel 0.0.0 -map_channel 0.0.1? OUTPUT
-map_metadata[:metadata_spec_out] infile[:metadata_spec_in]
(output,per-metadata)
Set metadata information of the next output file from infile. Note
that those are file indices (zero-based), not filenames. Optional
metadata_spec_in/out parameters specify, which metadata to copy. A
metadata specifier can have the following forms:
g global metadata, i.e. metadata that applies to the whole file
s[:stream_spec]
per-stream metadata. 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.
c:chapter_index
per-chapter metadata. chapter_index is the zero-based chapter
index.
p:program_index
per-program metadata. program_index is the zero-based program
index.
If metadata specifier is omitted, it defaults to global.
By default, global metadata is copied from the first input file,
per-stream and per-chapter metadata is copied along with
streams/chapters. These default mappings are disabled by creating
any mapping of the relevant type. A negative file index can be used
to create a dummy mapping that just disables automatic copying.
For example to copy metadata from the first stream of the input
file to global metadata of the output file:
ffmpeg -i in.ogg -map_metadata 0:s:0 out.mp3
To do the reverse, i.e. copy global metadata to all audio streams:
ffmpeg -i in.mkv -map_metadata:s:a 0:g out.mkv
Note that simple 0 would work as well in this example, since global
metadata is assumed by default.
-map_chapters input_file_index (output)
Copy chapters from input file with index 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.
-benchmark (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.
-benchmark_all (global)
Show benchmarking information during the encode. Shows real,
system and user time used in various steps (audio/video
encode/decode).
-timelimit duration (global)
Exit after ffmpeg has been running for duration seconds in CPU user
time.
-dump (global)
Dump each input packet to stderr.
-hex (global)
When dumping packets, also dump the payload.
-readrate speed (input)
Limit input read speed.
Its value is a floating-point positive number which represents the
maximum duration of media, in seconds, that should be ingested in
one second of wallclock time. Default value is zero and represents
no imposed limitation on speed of ingestion. Value 1 represents
real-time speed and is equivalent to "-re".
Mainly used to simulate a capture device or live input stream (e.g.
when reading from a file). Should not be used with a low value
when input is an actual capture device or live stream as it may
cause packet loss.
It is useful for when flow speed of output packets is important,
such as live streaming.
-re (input)
Read input at native frame rate. This is equivalent to setting
"-readrate 1".
-readrate_initial_burst seconds
Set an initial read burst time, in seconds, after which
-re/-readrate will be enforced.
-vsync parameter (global)
-fps_mode[:stream_specifier] parameter (output,per-stream)
Set video sync method / framerate mode. vsync is applied to all
output video streams but can be overridden for a stream by setting
fps_mode. vsync is deprecated and will be removed in the future.
For compatibility reasons some of the values for vsync can be
specified as numbers (shown in parentheses in the following table).
passthrough (0)
Each frame is passed with its timestamp from the demuxer to the
muxer.
cfr (1)
Frames will be duplicated and dropped to achieve exactly the
requested constant frame rate.
vfr (2)
Frames are passed through with their timestamp or dropped so as
to prevent 2 frames from having the same timestamp.
auto (-1)
Chooses between cfr and vfr depending on muxer capabilities.
This is the default method.
Note that the timestamps may be further modified by the muxer,
after this. For example, in the case that the format option
avoid_negative_ts is enabled.
With -map you can select from which stream the timestamps should be
taken. You can leave either video or audio unchanged and sync the
remaining stream(s) to the unchanged one.
-frame_drop_threshold 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.
-apad parameters (output,per-stream)
Pad the output audio stream(s). This is the same as applying "-af
apad". Argument is a string of filter parameters composed the same
as with the "apad" filter. "-shortest" must be set for this output
for the option to take effect.
-copyts
Do not process input timestamps, but keep their values without
trying to sanitize them. In particular, do not remove the initial
start time offset value.
Note that, depending on the vsync option or on specific muxer
processing (e.g. in case the format option avoid_negative_ts is
enabled) the output timestamps may mismatch with the input
timestamps even when this option is selected.
-start_at_zero
When used with copyts, shift input timestamps so they start at
zero.
This means that using e.g. "-ss 50" will make output timestamps
start at 50 seconds, regardless of what timestamp the input file
started at.
-copytb mode
Specify how to set the encoder timebase when stream copying. mode
is an integer numeric value, and can assume one of the following
values:
1 Use the demuxer timebase.
The time base is copied to the output encoder from the
corresponding input demuxer. This is sometimes required to
avoid non monotonically increasing timestamps when copying
video streams with variable frame rate.
0 Use the decoder timebase.
The time base is copied to the output encoder from the
corresponding input decoder.
-1 Try to make the choice automatically, in order to generate a
sane output.
Default value is -1.
-enc_time_base[:stream_specifier] timebase (output,per-stream)
Set the encoder timebase. timebase can assume one of the following
values:
0 Assign a default value according to the media type.
For video - use 1/framerate, for audio - use 1/samplerate.
demux
Use the timebase from the demuxer.
filter
Use the timebase from the filtergraph.
a positive number
Use the provided number as the timebase.
This field can be provided as a ratio of two integers (e.g.
1:24, 1:48000) or as a decimal number (e.g. 0.04166, 2.0833e-5)
Default value is 0.
-bitexact (input/output)
Enable bitexact mode for (de)muxer and (de/en)coder
-shortest (output)
Finish encoding when the shortest output stream ends.
Note that this option may require buffering frames, which
introduces extra latency. The maximum amount of this latency may be
controlled with the "-shortest_buf_duration" option.
-shortest_buf_duration duration (output)
The "-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 X this is typically the case for
subtitles).
This option controls the maximum duration of buffered frames in
seconds. Larger values may allow the "-shortest" option to produce
more accurate results, but increase memory use and latency.
The default value is 10 seconds.
-dts_delta_threshold threshold
Timestamp discontinuity delta threshold, expressed as a decimal
number of seconds.
The timestamp discontinuity correction enabled by this option is
only applied to input formats accepting timestamp discontinuity
(for which the "AVFMT_TS_DISCONT" flag is enabled), e.g. MPEG-TS
and HLS, and is automatically disabled when employing the "-copyts"
option (unless wrapping is detected).
If a timestamp discontinuity is detected whose absolute value is
greater than threshold, ffmpeg will remove the discontinuity by
decreasing/increasing the current DTS and PTS by the corresponding
delta value.
The default value is 10.
-dts_error_threshold threshold
Timestamp error delta threshold, expressed as a decimal number of
seconds.
The timestamp correction enabled by this option is only applied to
input formats not accepting timestamp discontinuity (for which the
"AVFMT_TS_DISCONT" flag is not enabled).
If a timestamp discontinuity is detected whose absolute value is
greater than threshold, ffmpeg will drop the PTS/DTS timestamp
value.
The default value is "3600*30" (30 hours), which is arbitrarily
picked and quite conservative.
-muxdelay seconds (output)
Set the maximum demux-decode delay.
-muxpreload seconds (output)
Set the initial demux-decode delay.
-streamid output-stream-index:new-value (output)
Assign a new stream-id value to an output stream. This option
should be specified prior to the output filename to which it
applies. For the situation where multiple output files exist, a
streamid may be reassigned to a different value.
For example, to set the stream 0 PID to 33 and the stream 1 PID to
36 for an output mpegts file:
ffmpeg -i inurl -streamid 0:33 -streamid 1:36 out.ts
-bsf[:stream_specifier] bitstream_filters (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).
bitstream_filters is a comma-separated list of bitstream filter
specifications, each of the form
<filter>[=<optname0>=<optval0>:<optname1>=<optval1>:...]
Any of the ',=:' characters that are to be a part of an option
value need to be escaped with a backslash.
Use the "-bsfs" option to get the list of bitstream filters.
E.g.
ffmpeg -bsf:v h264_mp4toannexb -i h264.mp4 -c:v copy -an out.h264
applies the "h264_mp4toannexb" bitstream filter (which converts
MP4-encapsulated H.264 stream to Annex B) to the input video
stream.
On the other hand,
ffmpeg -i file.mov -an -vn -bsf:s mov2textsub -c:s copy -f rawvideo sub.txt
applies the "mov2textsub" bitstream filter (which extracts text
from MOV subtitles) to the output subtitle stream. Note, however,
that since both examples use "-c copy", it matters little whether
the filters are applied on input or output - that would change if
transcoding was happening.
-tag[:stream_specifier] codec_tag (input/output,per-stream)
Force a tag/fourcc for matching streams.
-timecode hh:mm:ssSEPff
Specify Timecode for writing. SEP is ':' for non drop timecode and
';' (or '.') for drop.
ffmpeg -i input.mpg -timecode 01:02:03.04 -r 30000/1001 -s ntsc output.mpg
-filter_complex filtergraph (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 -filter options.
filtergraph is a description of the filtergraph, as described in
the ``Filtergraph syntax'' section of the ffmpeg-filters manual.
Input link labels must refer to input streams using the
"[file_index:stream_specifier]" syntax (i.e. the same as -map
uses). If stream_specifier matches multiple streams, the first one
will be used. An unlabeled input will be connected to the first
unused input stream of the matching type.
Output link labels are referred to with -map. Unlabeled outputs are
added to the first output file.
Note that with this option it is possible to use only lavfi sources
without normal input files.
For example, to overlay an image over video
ffmpeg -i video.mkv -i image.png -filter_complex '[0:v][1:v]overlay[out]' -map
'[out]' out.mkv
Here "[0:v]" refers to the first video stream in the first input
file, which is linked to the first (main) input of the overlay
filter. Similarly the first video stream in the second input is
linked to the second (overlay) input of overlay.
Assuming there is only one video stream in each input file, we can
omit input labels, so the above is equivalent to
ffmpeg -i video.mkv -i image.png -filter_complex 'overlay[out]' -map
'[out]' out.mkv
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
ffmpeg -i video.mkv -i image.png -filter_complex 'overlay' out.mkv
As a special exception, you can use a bitmap subtitle stream as
input: it will be converted into a video with the same size as the
largest video in the file, or 720x576 if no video is present. Note
that this is an experimental and temporary solution. It will be
removed once libavfilter has proper support for subtitles.
For example, to hardcode subtitles on top of a DVB-T recording
stored in MPEG-TS format, delaying the subtitles by 1 second:
ffmpeg -i input.ts -filter_complex \
'[#0x2ef] setpts=PTS+1/TB [sub] ; [#0x2d0] [sub] overlay' \
-sn -map '#0x2dc' output.mkv
(0x2d0, 0x2dc and 0x2ef are the MPEG-TS PIDs of respectively the
video, audio and subtitles streams; 0:0, 0:3 and 0:7 would have
worked too)
To generate 5 seconds of pure red video using lavfi "color" source:
ffmpeg -filter_complex 'color=c=red' -t 5 out.mkv
-filter_complex_threads nb_threads (global)
Defines how many threads are used to process a filter_complex
graph. Similar to filter_threads but used for "-filter_complex"
graphs only. The default is the number of available CPUs.
-lavfi filtergraph (global)
Define a complex filtergraph, i.e. one with arbitrary number of
inputs and/or outputs. Equivalent to -filter_complex.
-accurate_seek (input)
This option enables or disables accurate seeking in input files
with the -ss option. It is enabled by default, so seeking is
accurate when transcoding. Use -noaccurate_seek to disable it,
which may be useful e.g. when copying some streams and transcoding
the others.
-seek_timestamp (input)
This option enables or disables seeking by timestamp in input files
with the -ss option. It is disabled by default. If enabled, the
argument to the -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.
-thread_queue_size size (input/output)
For input, this option sets the maximum number of queued packets
when reading from the file or device. With low latency / high rate
live streams, packets may be discarded if they are not read in a
timely manner; setting this value can force ffmpeg to use a
separate input thread and read packets as soon as they arrive. By
default ffmpeg only does this if multiple inputs are specified.
For output, this option specified the maximum number of packets
that may be queued to each muxing thread.
-sdp_file file (global)
Print sdp information for an output stream to 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).
-discard (input)
Allows discarding specific streams or frames from streams. Any
input stream can be fully discarded, using value "all" whereas
selective discarding of frames from a stream occurs at the demuxer
and is not supported by all demuxers.
none
Discard no frame.
default
Default, which discards no frames.
noref
Discard all non-reference frames.
bidir
Discard all bidirectional frames.
nokey
Discard all frames excepts keyframes.
all Discard all frames.
-abort_on flags (global)
Stop and abort on various conditions. The following flags are
available:
empty_output
No packets were passed to the muxer, the output is empty.
empty_output_stream
No packets were passed to the muxer in some of the output
streams.
-max_error_rate (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.
-xerror (global)
Stop and exit on error
-max_muxing_queue_size packets (output,per-stream)
When transcoding audio and/or video streams, ffmpeg will not begin
writing into the output until it has one packet for each such
stream. While waiting for that to happen, packets for other streams
are buffered. This option sets the size of this buffer, in packets,
for the matching output stream.
The default value of this option should be high enough for most
uses, so only touch this option if you are sure that you need it.
-muxing_queue_data_threshold bytes (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.
-auto_conversion_filters (global)
Enable automatically inserting format conversion filters in all
filter graphs, including those defined by -vf, -af, -filter_complex
and -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 "-noauto_conversion_filters".
-bits_per_raw_sample[:stream_specifier] value (output,per-stream)
Declare the number of bits per raw sample in the given output
stream to be 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.
-stats_enc_pre[:stream_specifier] path (output,per-stream)
-stats_enc_post[:stream_specifier] path (output,per-stream)
-stats_mux_pre[:stream_specifier] path (output,per-stream)
Write per-frame encoding information about the matching streams
into the file given by path.
-stats_enc_pre writes information about raw video or audio frames
right before they are sent for encoding, while -stats_enc_post
writes information about encoded packets as they are received from
the encoder. -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 -stats_enc_pre_fmt / -stats_enc_post_fmt /
-stats_mux_pre_fmt.
When stats for multiple streams are written into a single file, the
lines corresponding to different streams will be interleaved. The
precise order of this interleaving is not specified and not
guaranteed to remain stable between different invocations of the
program, even with the same options.
-stats_enc_pre_fmt[:stream_specifier] format_spec (output,per-stream)
-stats_enc_post_fmt[:stream_specifier] format_spec (output,per-stream)
-stats_mux_pre_fmt[:stream_specifier] format_spec (output,per-stream)
Specify the format for the lines written with -stats_enc_pre /
-stats_enc_post / -stats_mux_pre.
format_spec is a string that may contain directives of the form
{fmt}. format_spec is backslash-escaped --- use \{, \}, and \\ to
write a literal {, }, or \, respectively, into the output.
The directives given with fmt may be one of the following:
fidx
Index of the output file.
sidx
Index of the output stream in the file.
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.
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.
tb Timebase in which this frame/packet's timestamps are expressed,
as a rational number num/den. Note that encoder and muxer may
use different timebases.
tbi Timebase for ptsi, as a rational number num/den. Available when
ptsi is available, 0/1 otherwise.
pts Presentation timestamp of the frame or packet, as an integer.
Should be multiplied by the timebase to compute presentation
time.
ptsi
Presentation timestamp of the input frame (see ni), as an
integer. Should be multiplied by tbi to compute presentation
time. Printed as (2^63 - 1 = 9223372036854775807) when not
available.
t Presentation time of the frame or packet, as a decimal number.
Equal to pts multiplied by tb.
ti Presentation time of the input frame (see ni), as a decimal
number. Equal to ptsi multiplied by tbi. Printed as inf when
not available.
dts (packet)
Decoding timestamp of the packet, as an integer. Should be
multiplied by the timebase to compute presentation time.
dt (packet)
Decoding time of the frame or packet, as a decimal number.
Equal to dts multiplied by tb.
sn (frame,audio)
Number of audio samples sent to the encoder so far.
samp (frame,audio)
Number of audio samples in the frame.
size (packet)
Size of the encoded packet in bytes.
br (packet)
Current bitrate in bits per second.
abr (packet)
Average bitrate for the whole stream so far, in bits per
second, -1 if it cannot be determined at this point.
key (packet)
Character 'K' if the packet contains a keyframe, character 'N'
otherwise.
Directives tagged with packet may only be used with
-stats_enc_post_fmt and -stats_mux_pre_fmt.
Directives tagged with frame may only be used with
-stats_enc_pre_fmt.
Directives tagged with audio may only be used with audio streams.
The default format strings are:
pre-encoding
{fidx} {sidx} {n} {t}
post-encoding
{fidx} {sidx} {n} {t}
In the future, new items may be added to the end of the default
formatting strings. Users who depend on the format staying exactly
the same, should prescribe it manually.
Note that stats for different streams written into the same file
may have different formats.
Preset files
A preset file contains a sequence of option=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
presets directory in the FFmpeg source tree for examples.
There are two types of preset files: ffpreset and avpreset files.
ffpreset files
ffpreset files are specified with the "vpre", "apre", "spre", and
"fpre" options. The "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 "vpre", "apre", and "spre" options, the options
specified in a preset file are applied to the currently selected codec
of the same type as the preset option.
The argument passed to the "vpre", "apre", and "spre" preset options
identifies the preset file to use according to the following rules:
First ffmpeg searches for a file named arg.ffpreset in the directories
$FFMPEG_DATADIR (if set), and $HOME/.ffmpeg, and in the datadir defined
at configuration time (usually PREFIX/share/ffmpeg) or in a ffpresets
folder along the executable on win32, in that order. For example, if
the argument is "libvpx-1080p", it will search for the file
libvpx-1080p.ffpreset.
If no such file is found, then ffmpeg will search for a file named
codec_name-arg.ffpreset in the above-mentioned directories, where
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
"-vcodec libvpx" and use "-vpre 1080p", then it will search for the
file libvpx-1080p.ffpreset.
avpreset files
avpreset files are specified with the "pre" option. They work similar
to ffpreset files, but they only allow encoder- specific options.
Therefore, an option=value pair specifying an encoder cannot be used.
When the "pre" option is specified, ffmpeg will look for files with the
suffix .avpreset in the directories $AVCONV_DATADIR (if set), and
$HOME/.avconv, and in the datadir defined at configuration time
(usually PREFIX/share/ffmpeg), in that order.
First ffmpeg searches for a file named codec_name-arg.avpreset in the
above-mentioned directories, where 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 "-vcodec libvpx" and use "-pre 1080p", then
it will search for the file libvpx-1080p.avpreset.
If no such file is found, then ffmpeg will search for a file named
arg.avpreset in the same directories.
vstats file format
The "-vstats" and "-vstats_file" options enable generation of a file
containing statistics about the generated video outputs.
The "-vstats_version" option controls the format version of the
generated file.
With version 1 the format is:
frame= <FRAME> q= <FRAME_QUALITY> PSNR= <PSNR> f_size= <FRAME_SIZE> s_size= <STREAM_SIZE>kB time= <TIMESTAMP> br= <BITRATE>kbits/s avg_br= <AVERAGE_BITRATE>kbits/s
With version 2 the format is:
out= <OUT_FILE_INDEX> st= <OUT_FILE_STREAM_INDEX> frame= <FRAME_NUMBER> q= <FRAME_QUALITY>f PSNR= <PSNR> f_size= <FRAME_SIZE> s_size= <STREAM_SIZE>kB time= <TIMESTAMP> br= <BITRATE>kbits/s avg_br= <AVERAGE_BITRATE>kbits/s
The value corresponding to each key is described below:
avg_br
average bitrate expressed in Kbits/s
br bitrate expressed in Kbits/s
frame
number of encoded frame
out out file index
PSNR
Peak Signal to Noise Ratio
q quality of the frame
f_size
encoded packet size expressed as number of bytes
s_size
stream size expressed in KiB
st out file stream index
time
time of the packet
type
picture type
See also the -stats_enc options for an alternative way to show encoding
statistics.
EXAMPLES
Video and Audio grabbing
If you specify the input format and device then ffmpeg can grab video
and audio directly.
ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
Or with an ALSA audio source (mono input, card id 1) instead of OSS:
ffmpeg -f alsa -ac 1 -i hw:1 -f video4linux2 -i /dev/video0 /tmp/out.mpg
Note that you must activate the right video source and channel before
launching ffmpeg with any TV viewer such as
<http://linux.bytesex.org/xawtv/> by Gerd Knorr. You also have to set
the audio recording levels correctly with a standard mixer.
X11 grabbing
Grab the X11 display with ffmpeg via
ffmpeg -f x11grab -video_size cif -framerate 25 -i :0.0 /tmp/out.mpg
0.0 is display.screen number of your X11 server, same as the DISPLAY
environment variable.
ffmpeg -f x11grab -video_size cif -framerate 25 -i :0.0+10,20 /tmp/out.mpg
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.
Video and Audio file format conversion
Any supported file format and protocol can serve as input to ffmpeg:
Examples:
o You can use YUV files as input:
ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
It will use the files:
/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
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 -s
option if ffmpeg cannot guess it.
o You can input from a raw YUV420P file:
ffmpeg -i /tmp/test.yuv /tmp/out.avi
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.
o You can output to a raw YUV420P file:
ffmpeg -i mydivx.avi hugefile.yuv
o You can set several input files and output files:
ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
Converts the audio file a.wav and the raw YUV video file a.yuv to
MPEG file a.mpg.
o You can also do audio and video conversions at the same time:
ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
Converts a.wav to MPEG audio at 22050 Hz sample rate.
o You can encode to several formats at the same time and define a
mapping from input stream to output streams:
ffmpeg -i /tmp/a.wav -map 0:a -b:a 64k /tmp/a.mp2 -map 0:a -b:a 128k /tmp/b.mp2
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.
o You can transcode decrypted VOBs:
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
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
"--enable-libmp3lame" to configure. The mapping is particularly
useful for DVD transcoding to get the desired audio language.
NOTE: To see the supported input formats, use "ffmpeg -demuxers".
o You can extract images from a video, or create a video from many
images:
For extracting images from a video:
ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg
This will extract one video frame per second from the video and
will output them in files named foo-001.jpeg, foo-002.jpeg, etc.
Images will be rescaled to fit the new WxH values.
If you want to extract just a limited number of frames, you can use
the above command in combination with the "-frames:v" or "-t"
option, or in combination with -ss to start extracting from a
certain point in time.
For creating a video from many images:
ffmpeg -f image2 -framerate 12 -i foo-%03d.jpeg -s WxH foo.avi
The syntax "foo-%03d.jpeg" specifies to use a decimal number
composed of three digits padded with zeroes to express the sequence
number. It is the same syntax supported by the C printf function,
but only formats accepting a normal integer are suitable.
When importing an image sequence, -i also supports expanding shell-
like wildcard patterns (globbing) internally, by selecting the
image2-specific "-pattern_type glob" option.
For example, for creating a video from filenames matching the glob
pattern "foo-*.jpeg":
ffmpeg -f image2 -pattern_type glob -framerate 12 -i 'foo-*.jpeg' -s WxH foo.avi
o You can put many streams of the same type in the output:
ffmpeg -i test1.avi -i test2.avi -map 1:1 -map 1:0 -map 0:1 -map 0:0 -c copy -y test12.nut
The resulting output file test12.nut will contain the first four
streams from the input files in reverse order.
o To force CBR video output:
ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
o The four options lmin, lmax, mblmin and mblmax use 'lambda' units,
but you may use the QP2LAMBDA constant to easily convert from 'q'
units:
ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
SEE ALSO
ffmpeg-all(1), 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)
AUTHORS
The FFmpeg developers.
For details about the authorship, see the Git history of the project
(https://git.ffmpeg.org/ffmpeg), e.g. by typing the command git log in
the FFmpeg source directory, or browsing the online repository at
<https://git.ffmpeg.org/ffmpeg>.
Maintainers for the specific components are listed in the file
MAINTAINERS in the source code tree.
FFMPEG(1)
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