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.
ffmpeg -i input.avi -b:v 64k -bufsize 64k output.avi
ffmpeg -i input.avi -r 24 output.avi
ffmpeg -r 1 -i input.m2v -r 24 output.avi
_______ ______________ | | | | | 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.
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 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.
_______ ______________ ________ | | | | | | | 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.
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:
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.
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 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.
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.
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.
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:
Note that in ffmpeg, matching by metadata will only work properly for input files.
Possible values of arg are:
Note that the term 'codec' is used throughout this documentation as a shortcut for what is more correctly called a media bitstream format.
ffmpeg -sources pulse,server=192.168.0.4
ffmpeg -sinks pulse,server=192.168.0.4
The optional flags prefix can consist of the following values:
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:
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.
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:
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.
All FFmpeg tools will normally show a copyright notice, build options and library versions. This option can be used to suppress printing this information.
ffmpeg -cpuflags -sse+mmx ... ffmpeg -cpuflags mmx ... ffmpeg -cpuflags 0 ...
Possible flags for this option are:
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.
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.
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 and -t are mutually exclusive and -t has priority.
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.
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.
date must be a date specification, see the Date section in the ffmpeg-utils(1) manual.
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
This option overrides the disposition copied from the input stream. It is also possible to delete the disposition by setting it to 0.
The following dispositions are recognized:
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.
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
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.
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.
Progress information is written approximately every second 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''.
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.
See also the option "-fdebug ts".
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).
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.
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, duplicate or drop input frames to achieve constant output frame rate fps.
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 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.
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.
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
This is an alias for "-filter:v", see the -filter option.
version = 1 :
"frame= %5d q= %2.1f PSNR= %6.2f f_size= %6d s_size= %8.0fkB time= %0.3f br= %7.1fkbits/s avg_br= %7.1fkbits/s"
version > 1:
"out= %2d st= %2d frame= %5d q= %2.1f PSNR= %6.2f f_size= %6d s_size= %8.0fkB time= %0.3f br= %7.1fkbits/s avg_br= %7.1fkbits/s"
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:
The expression in expr can contain the following constants:
For example to force a key frame every 5 seconds, you can specify:
To force a key frame 5 seconds after the time of the last forced one, starting from second 13:
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.
The meaning of device and the following arguments depends on the device type:
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 vaapi) and then deriving a QSV device from that.)
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:
The indices and filters must together uniquely select a device.
The following options are recognized:
This is a global setting, so all filters will receive the same device.
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.
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.
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.
This is an alias for "-filter:a", see the -filter option.
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.
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.
The first "-map" option on the command line specifies the source for output stream 0, the second "-map" option specifies the source for output stream 1, etc.
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.
For example, to map ALL streams from the first input file to output
ffmpeg -i INPUT -map 0 output
For example, if you have two audio streams in the first input file, these streams are identified by ``0:0'' and ``0:1''. You can use "-map" to select which streams to place in an output file. For example:
ffmpeg -i INPUT -map 0:1 out.wav
will map the input stream in INPUT identified by ``0:1'' to the (single) output stream in out.wav.
For example, 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
To select all video and the third audio stream from an input file:
ffmpeg -i INPUT -map 0:v -map 0:a:2 OUTPUT
To map all the streams except the second audio, use negative mappings
ffmpeg -i INPUT -map 0 -map -0:a:1 OUTPUT
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
To pick the English audio stream:
ffmpeg -i INPUT -map 0:m:language:eng OUTPUT
Note that using this option disables the default mappings for this output file.
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
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.
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.
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.
This option has been deprecated. Use the "aresample" audio filter instead.
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.
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.
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.
The time base is copied to the output encoder from the corresponding input decoder.
Default value is -1.
For video - use 1/framerate, for audio - use 1/samplerate.
If an input stream is not available, the default timebase will be used.
This field can be provided as a ratio of two integers (e.g. 1:24, 1:48000) or as a floating point number (e.g. 0.04166, 2.0833e-5)
Default value is 0.
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
ffmpeg -i h264.mp4 -c:v copy -bsf:v h264_mp4toannexb -an out.h264 ffmpeg -i file.mov -an -vn -bsf:s mov2textsub -c:s copy -f rawvideo sub.txt
ffmpeg -i input.mpg -timecode 01:02:03.04 -r 30000/1001 -s ntsc output.mpg
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
To generate 5 seconds of pure red video using lavfi "color" source:
ffmpeg -filter_complex 'color=c=red' -t 5 out.mkv
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.
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
There are two types of preset files: ffpreset and avpreset 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 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.
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.
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
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.
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.
ffmpeg -i mydivx.avi hugefile.yuv
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.
ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
Converts a.wav to MPEG audio at 22050 Hz sample rate.
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.
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".
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
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.
ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
For details about the authorship, see the Git history of the project (git://source.ffmpeg.org/ffmpeg), e.g. by typing the command git log in the FFmpeg source directory, or browsing the online repository at <http://source.ffmpeg.org>.
Maintainers for the specific components are listed in the file MAINTAINERS in the source code tree.