Linux Blog

FFMPEG

Section: (1)
Updated: 2007-10-02
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NAME

ffmpeg - FFmpeg video converter  

SYNOPSIS

ffmpeg [[infile options][-i infile]]... {[outfile options] outfile}...  

DESCRIPTION

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.

* To set the video bitrate of the output file to 64kbit/s:

        ffmpeg -i input.avi -b 64k output.avi

* To force the frame rate of the input and output file to 24 fps:

        ffmpeg -r 24 -i input.avi output.avi

* To force the frame rate of the output file to 24 fps:

        ffmpeg -i input.avi -r 24 output.avi

* To force the frame rate of input file to 1 fps and the output file to 24 fps:

        ffmpeg -r 1 -i input.avi -r 24 output.avi

The format option may be needed for raw input files.

By default, FFmpeg tries to convert as losslessly as possible: It uses the same audio and video parameters for the outputs as the one specified for the inputs.  

OPTIONS

 

Main options

-L
Show license.
-h
Show help.
-version
Show version.
-formats
Show available formats, codecs, protocols, ...
-f fmt
Force format.
-i filename
input filename
-y
Overwrite output files.
-t duration
Restrict the transcoded/captured video sequence to the duration specified in seconds. "hh:mm:ss[.xxx]" syntax is also supported.
-fs limit_size
Set the file size limit.
-ss position
Seek to given time position in seconds. "hh:mm:ss[.xxx]" syntax is also supported.
-itsoffset offset
Set the input time offset in seconds. "[-]hh:mm:ss[.xxx]" syntax is also supported. This option affects all the input files that follow it. The offset is added to the timestamps of the input files. Specifying a positive offset means that the corresponding streams are delayed by 'offset' seconds.
-title string
Set the title.
-timestamp time
Set the timestamp.
-author string
Set the author.
-copyright string
Set the copyright.
-comment string
Set the comment.
-album string
Set the album.
-track number
Set the track.
-year number
Set the year.
-v verbose
Control amount of logging.
-target type
Specify target file type (``vcd'', ``svcd'', ``dvd'', ``dv'', ``dv50'', ``pal-vcd'', ``ntsc-svcd'', ... ). 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

-dframes number
Set the number of data frames to record.
-scodec codec
Force subtitle codec ('copy' to copy stream).
-newsubtitle
Add a new subtitle stream to the current output stream.
-slang code
Set the ISO 639 language code (3 letters) of the current subtitle stream.
 

Video Options

-b bitrate
Set the video bitrate in bit/s (default = 200 kb/s).
-vframes number
Set the number of video frames to record.
-r fps
Set frame rate (Hz value, fraction or abbreviation), (default = 25).
-s size
Set frame size. The format is wxh (ffserver default = 160x128, ffmpeg default = same as source). The following abbreviations are recognized:
sqcif
128x96
qcif
176x144
cif
352x288
4cif
704x576
qqvga
160x120
qvga
320x240
vga
640x480
svga
800x600
xga
1024x768
uxga
1600x1200
qxga
2048x1536
sxga
1280x1024
qsxga
2560x2048
hsxga
5120x4096
wvga
852x480
wxga
1366x768
wsxga
1600x1024
wuxga
1920x1200
woxga
2560x1600
wqsxga
3200x2048
wquxga
3840x2400
whsxga
6400x4096
whuxga
7680x4800
cga
320x200
ega
640x350
hd480
852x480
hd720
1280x720
hd1080
1920x1080
-aspect aspect
Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
-croptop size
Set top crop band size (in pixels).
-cropbottom size
Set bottom crop band size (in pixels).
-cropleft size
Set left crop band size (in pixels).
-cropright size
Set right crop band size (in pixels).
-padtop size
Set top pad band size (in pixels).
-padbottom size
Set bottom pad band size (in pixels).
-padleft size
Set left pad band size (in pixels).
-padright size
Set right pad band size (in pixels).
-padcolor (hex color)
Set color of padded bands. The value for padcolor is expressed as a six digit hexadecimal number where the first two digits represent red, the middle two digits green and last two digits blue (default = 000000 (black)).
-vn
Disable video recording.
-bt tolerance
Set video bitrate tolerance (in bit/s).
-maxrate bitrate
Set max video bitrate (in bit/s).
-minrate bitrate
Set min video bitrate (in bit/s).
-bufsize size
Set video buffer verifier buffer size (in bits).
-vcodec codec
Force video codec to codec. Use the "copy" special value to tell that the raw codec data must be copied as is.
-sameq
Use same video quality as source (implies VBR).
-pass n
Select the pass number (1 or 2). It is useful to do two pass encoding. The statistics of the video are recorded in the first pass and the video is generated at the exact requested bitrate in the second pass.
-passlogfile file
Set two pass logfile name to file.
-newvideo
Add a new video stream to the current output stream.
 

Advanced Video Options

-pix_fmt format
Set pixel format. Use 'list' as parameter to show all the supported pixel formats.
-sws_flags flags
Set SwScaler flags (only available when compiled with SwScaler support).
-g gop_size
Set the group of pictures size.
-intra
Use only intra frames.
-vdt n
Discard threshold.
-qscale q
Use fixed video quantizer scale (VBR).
-qmin q
minimum video quantizer scale (VBR)
-qmax q
maximum video quantizer scale (VBR)
-qdiff q
maximum difference between the quantizer scales (VBR)
-qblur blur
video quantizer scale blur (VBR)
-qcomp compression
video quantizer scale compression (VBR)
-lmin lambda
minimum video lagrange factor (VBR)
-lmax lambda
max video lagrange factor (VBR)
-mblmin lambda
minimum macroblock quantizer scale (VBR)
-mblmax lambda
maximum macroblock quantizer scale (VBR)

These four options (lmin, lmax, mblmin, 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

-rc_init_cplx complexity
initial complexity for single pass encoding
-b_qfactor factor
qp factor between P- and B-frames
-i_qfactor factor
qp factor between P- and I-frames
-b_qoffset offset
qp offset between P- and B-frames
-i_qoffset offset
qp offset between P- and I-frames
-rc_eq equation
Set rate control equation (default = "tex^qComp").
-rc_override override
rate control override for specific intervals
-me_method method
Set motion estimation method to method. Available methods are (from lowest to best quality):
zero
Try just the (0, 0) vector.
phods
log
x1
hex
umh
epzs
(default method)
full
exhaustive search (slow and marginally better than epzs)
-dct_algo algo
Set DCT algorithm to algo. Available values are:
0
FF_DCT_AUTO (default)
1
FF_DCT_FASTINT
2
FF_DCT_INT
3
FF_DCT_MMX
4
FF_DCT_MLIB
5
FF_DCT_ALTIVEC
-idct_algo algo
Set IDCT algorithm to algo. Available values are:
0
FF_IDCT_AUTO (default)
1
FF_IDCT_INT
2
FF_IDCT_SIMPLE
3
FF_IDCT_SIMPLEMMX
4
FF_IDCT_LIBMPEG2MMX
5
FF_IDCT_PS2
6
FF_IDCT_MLIB
7
FF_IDCT_ARM
8
FF_IDCT_ALTIVEC
9
FF_IDCT_SH4
10
FF_IDCT_SIMPLEARM
-er n
Set error resilience to n.
1
FF_ER_CAREFUL (default)
2
FF_ER_COMPLIANT
3
FF_ER_AGGRESSIVE
4
FF_ER_VERY_AGGRESSIVE
-ec bit_mask
Set error concealment to bit_mask. bit_mask is a bit mask of the following values:
1
FF_EC_GUESS_MVS (default = enabled)
2
FF_EC_DEBLOCK (default = enabled)
-bf frames
Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
-mbd mode
macroblock decision
0
FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
1
FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
2
FF_MB_DECISION_RD: rate distortion
-4mv
Use four motion vector by macroblock (MPEG-4 only).
-part
Use data partitioning (MPEG-4 only).
-bug param
Work around encoder bugs that are not auto-detected.
-strict strictness
How strictly to follow the standards.
-aic
Enable Advanced intra coding (h263+).
-umv
Enable Unlimited Motion Vector (h263+)
-deinterlace
Deinterlace pictures.
-ilme
Force interlacing support in encoder (MPEG-2 and MPEG-4 only). Use this option if your input file is interlaced and you want to keep the interlaced format for minimum losses. The alternative is to deinterlace the input stream with -deinterlace, but deinterlacing introduces losses.
-psnr
Calculate PSNR of compressed frames.
-vstats
Dump video coding statistics to vstats_HHMMSS.log.
-vstats_file file
Dump video coding statistics to file.
-vhook module
Insert video processing module. module contains the module name and its parameters separated by spaces.
-top n
top=1/bottom=0/auto=-1 field first
-dc precision
Intra_dc_precision.
-vtag fourcc/tag
Force video tag/fourcc.
-qphist
Show QP histogram.
-vbsf bitstream filter
Bitstream filters available are ``dump_extra'', ``remove_extra'', ``noise''.
 

Audio Options

-aframes number
Set the number of audio frames to record.
-ar freq
Set the audio sampling frequency (default = 44100 Hz).
-ab bitrate
Set the audio bitrate in bit/s (default = 64k).
-ac channels
Set the number of audio channels (default = 1).
-an
Disable audio recording.
-acodec codec
Force audio codec to codec. Use the "copy" special value to specify that the raw codec data must be copied as is.
-newaudio
Add a new audio track to the output file. If you want to specify parameters, do so before "-newaudio" ("-acodec", "-ab", etc..).

Mapping will be done automatically, if the number of output streams is equal to the number of input streams, else it will pick the first one that matches. You can override the mapping using "-map" as usual.

Example:

        ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio

-alang code
Set the ISO 639 language code (3 letters) of the current audio stream.
 

Advanced Audio options:

-atag fourcc/tag
Force audio tag/fourcc.
-absf bitstream filter
Bitstream filters available are ``dump_extra'', ``remove_extra'', ``noise'', ``mp3comp'', ``mp3decomp''.
 

Subtitle options:

-scodec codec
Force subtitle codec ('copy' to copy stream).
-newsubtitle
Add a new subtitle stream to the current output stream.
-slang code
Set the ISO 639 language code (3 letters) of the current subtitle stream.
 

Audio/Video grab options

-vc channel
Set video grab channel (DV1394 only).
-tvstd standard
Set television standard (NTSC, PAL (SECAM)).
-isync
Synchronize read on input.
 

Advanced options

-map input stream id[:input stream id]
Set stream mapping from input streams to output streams. Just enumerate the input streams in the order you want them in the output. [input stream id] sets the (input) stream to sync against.
-map_meta_data outfile:infile
Set meta data information of outfile from infile.
-debug
Print specific debug info.
-benchmark
Add timings for benchmarking.
-dump
Dump each input packet.
-hex
When dumping packets, also dump the payload.
-bitexact
Only use bit exact algorithms (for codec testing).
-ps size
Set packet size in bits.
-re
Read input at native frame rate. Mainly used to simulate a grab device.
-loop_input
Loop over the input stream. Currently it works only for image streams. This option is used for automatic FFserver testing.
-loop_output number_of_times
Repeatedly loop output for formats that support looping such as animated GIF (0 will loop the output infinitely).
-threads count
Thread count.
-vsync parameter
Video sync method. Video will be stretched/squeezed to match the timestamps, it is done by duplicating and dropping frames. 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.
-async samples_per_second
Audio sync method. ``Stretches/squeezes'' the audio stream to match the timestamps, the parameter is the maximum samples per second by which the audio is changed. -async 1 is a special case where only the start of the audio stream is corrected without any later correction.
-copyts
Copy timestamps from input to output.
-shortest
Finish encoding when the shortest input stream ends.
-dts_delta_threshold
Timestamp discontinuity delta threshold.
-muxdelay seconds
Set the maximum demux-decode delay.
-muxpreload seconds
Set the initial demux-decode delay.
 

FFmpeg formula evaluator

When evaluating a rate control string, FFmpeg uses an internal formula evaluator.

The following binary operators are available: "+", "-", "*", "/", "^".

The following unary operators are available: "+", "-", "(...)".

The following functions are available:

sinh(x)
cosh(x)
tanh(x)
sin(x)
cos(x)
tan(x)
exp(x)
log(x)
squish(x)
gauss(x)
abs(x)
max(x, y)
min(x, y)
gt(x, y)
lt(x, y)
eq(x, y)
bits2qp(bits)
qp2bits(qp)

The following constants are available:

PI
E
iTex
pTex
tex
mv
fCode
iCount
mcVar
var
isI
isP
isB
avgQP
qComp
avgIITex
avgPITex
avgPPTex
avgBPTex
avgTex
 

EXAMPLES

 

Video and Audio grabbing

FFmpeg can grab video and audio from devices given that you specify the input format and device.

        ffmpeg -f oss -i /dev/dsp -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 xawtv (<http://bytesex.org/xawtv/>) by Gerd Knorr. You also have to set the audio recording levels correctly with a standard mixer.  

X11 grabbing

FFmpeg can grab the X11 display.

        ffmpeg -f x11grab -s cif -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 -s cif -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

* FFmpeg can use any supported file format and protocol as input:

Examples:

* 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.

* 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.

* You can output to a raw YUV420P file:

        ffmpeg -i mydivx.avi hugefile.yuv

* 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.

* 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 22050Hz sample rate.

* 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 -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0

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.

* You can transcode decrypted VOBs

        ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec libmp3lame -ab 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 -formats".  

SEE ALSO

ffserver(1), ffplay(1) and the HTML documentation of ffmpeg.  

AUTHOR

Fabrice Bellard


 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
Main options
Video Options
Advanced Video Options
Audio Options
Advanced Audio options:
Subtitle options:
Audio/Video grab options
Advanced options
FFmpeg formula evaluator
EXAMPLES
Video and Audio grabbing
X11 grabbing
Video and Audio file format conversion
SEE ALSO
AUTHOR




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