-h, -?, -help, --help
Show help.
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-version
Show version.
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-formats
Show available formats.
The fields preceding the format names have the following meanings:
D Decoding available
E Encoding available
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-codecs
Show available codecs.
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-bsfs
Show available bitstream filters.
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-protocols
Show available protocols.
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-filters
Show available libavfilter filters.
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-pix_fmts
Show available pixel formats.
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-sample_fmts
Show available sample formats.
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-loglevel loglevel | -v loglevel
Set the logging level used by the library. loglevel is a number or a string containing one of the
following values:
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-i filename (input)
input file name
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-y (global)
Overwrite output files without asking.
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-t duration (output)
Stop writing the output after its duration reaches duration. duration may be a number in seconds, or
in "hh:mm:ss[.xxx]" form.
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-fs limit_size (output)
Set the file size limit.
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-ss position (input/output)
When used as an input option (before "-i"), seeks in this input file to position. When used as an
output option (before an output filename), decodes but discards input until the timestamps reach
position. This is slower, but more accurate.
position may be either in seconds or in "hh:mm:ss[.xxx]" form.
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-itsoffset offset (input)
Set the input time offset in seconds. "[-]hh:mm:ss[.xxx]" syntax is also supported. 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.
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-metadata[:metadata_specifier] key=value (output,per-metadata)
Set a metadata key/value pair.
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-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:
avconv -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:
avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
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-dframes number (output)
Set the number of data frames to record. This is an alias for "-frames:d".
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-frames[:stream_specifier] framecount (output,per-stream)
Stop writing to the stream after framecount frames.
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-q[:stream_specifier] q (output,per-stream)
-qscale[:stream_specifier] q (output,per-stream)
Use fixed quality scale (VBR). The meaning of q is codec-dependent.
-filter[:stream_specifier] filter_graph (output,per-stream)
filter_graph is a description of the filter graph to apply to the stream. Use "-filters" to show all
the available filters (including also sources and sinks).
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-pre[:stream_specifier] preset_name (output,per-stream)
Specify the preset for matching stream(s).
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-stats (global)
Print encoding progress/statistics. On by default.
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-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:
avconv -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).
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-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.
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-r[:stream_specifier] fps (input/output,per-stream)
Set frame rate (Hz value, fraction or abbreviation), (default = 25).
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-s[:stream_specifier] size (input/output,per-stream)
Set frame size. The format is wxh (default - same as source). The following abbreviations are
recognized:
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-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.
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-vn (output)
Disable video recording.
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-bt tolerance
Set video bitrate tolerance (in bits, default 4000k). Has a minimum value of:
(target_bitrate/target_framerate). In 1-pass mode, bitrate tolerance specifies how far ratecontrol
is willing to deviate from the target average bitrate value. This is not related to min/max bitrate.
Lowering tolerance too much has an adverse effect on quality.
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-maxrate bitrate
Set max video bitrate (in bit/s). Requires -bufsize to be set.
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-minrate bitrate
Set min video bitrate (in bit/s). Most useful in setting up a CBR encode:
avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v
It is of little use elsewise.
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-bufsize size
Set video buffer verifier buffer size (in bits).
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-vcodec codec (output)
Set the video codec. This is an alias for "-codec:v".
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-same_quant
Use same quantizer as source (implies VBR).
Note that this is NOT SAME QUALITY. Do not use this option unless you know you need it.
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-pass n
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:
avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL
avconv -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null
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-passlogfile prefix (global)
Set two-pass log file name prefix to prefix, the default file name prefix is ``av2pass''. The
complete file name will be PREFIX-N.log, where N is a number specific to the output stream.
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-vf filter_graph (output)
filter_graph is a description of the filter graph to apply to the input video. Use the option
"-filters" to show all the available filters (including also sources and sinks). This is an alias
for "-filter:v".
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.
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-sws_flags flags (input/output)
Set SwScaler flags.
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-g gop_size
Set the group of pictures size.
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-vdt n
Discard threshold.
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-qmin q
minimum video quantizer scale (VBR)
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-qmax q
maximum video quantizer scale (VBR)
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-qdiff q
maximum difference between the quantizer scales (VBR)
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-qblur blur
video quantizer scale blur (VBR) (range 0.0 - 1.0)
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-qcomp compression
video quantizer scale compression (VBR) (default 0.5). Constant of ratecontrol equation. Recommended
range for default rc_eq: 0.0-1.0
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-lmin lambda
minimum video lagrange factor (VBR)
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-lmax lambda
max video lagrange factor (VBR)
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-mblmin lambda
minimum macroblock quantizer scale (VBR)
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-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:
avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext
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-rc_init_cplx complexity
initial complexity for single pass encoding
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-b_qfactor factor
qp factor between P- and B-frames
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-i_qfactor factor
qp factor between P- and I-frames
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-b_qoffset offset
qp offset between P- and B-frames
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-i_qoffset offset
qp offset between P- and I-frames
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-rc_eq equation
Set rate control equation (see section "Expression Evaluation") (default = "tex^qComp").
When computing the rate control equation expression, besides the standard functions defined in the
section "Expression Evaluation", the following functions are available:
bits2qp(bits)
qp2bits(qp)
and the following constants are available:
iTex
pTex
tex
mv
fCode
iCount
mcVar
var
isI
isP
isB
avgQP
qComp
avgIITex
avgPITex
avgPPTex
avgBPTex
avgTex
-rc_override[:stream_specifier] override (output,per-stream)
rate control override for specific intervals
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-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)
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-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
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-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)
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-bf frames
Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
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-mbd mode
macroblock decision
0 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv).
1 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
2 FF_MB_DECISION_RD: rate distortion
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-bug param
Work around encoder bugs that are not auto-detected.
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-strict strictness
How strictly to follow the standards.
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-deinterlace
Deinterlace pictures.
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-vstats
Dump video coding statistics to vstats_HHMMSS.log.
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-vstats_file file
Dump video coding statistics to file.
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-top[:stream_specifier] n (output,per-stream)
top=1/bottom=0/auto=-1 field first
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-dc precision
Intra_dc_precision.
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-vtag fourcc/tag (output)
Force video tag/fourcc. This is an alias for "-tag:v".
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-qphist (global)
Show QP histogram.
-force_key_frames[:stream_specifier] time[,time...] (output,per-stream)
Force key frames at the specified timestamps, more precisely at the first frames after each specified
time. 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. The timestamps must be specified in ascending order.
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-copyinkf[:stream_specifier] (output,per-stream)
When doing stream copy, copy also non-key frames found at the beginning.
Audio Options
-aframes number (output)
Set the number of audio frames to record. This is an alias for "-frames:a".
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-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.
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-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.
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-an (output)
Disable audio recording.
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-acodec codec (input/output)
Set the audio codec. This is an alias for "-codec:a".
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-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.
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-atag fourcc/tag (output)
Force audio tag/fourcc. This is an alias for "-tag:a".
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-audio_service_type type
Set the type of service that the audio stream contains.
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-scodec codec (input/output)
Set the subtitle codec. This is an alias for "-codec:s".
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-sn (output)
Disable subtitle recording.
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-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.
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-debug
Print specific debug info.
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-benchmark (global)
Show benchmarking information at the end of an encode. Shows CPU time used and maximum memory
consumption. Maximum memory consumption is not supported on all systems, it will usually display as
0 if not supported.
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-timelimit duration (global)
Exit after avconv has been running for duration seconds.
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-dump (global)
Dump each input packet to stderr.
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-hex (global)
When dumping packets, also dump the payload.
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-ps size
Set RTP payload size in bytes.
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-re (input)
Read input at native frame rate. Mainly used to simulate a grab device.
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-threads count
Thread count.
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-vsync parameter
Video sync method.
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-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.
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-copyts
Copy timestamps from input to output.
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-copytb
Copy input stream time base from input to output when stream copying.
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-shortest
Finish encoding when the shortest input stream ends.
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-dts_delta_threshold
Timestamp discontinuity delta threshold.
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-muxdelay seconds (input)
Set the maximum demux-decode delay.
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-muxpreload seconds (input)
Set the initial demux-decode delay.
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-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.
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-tag[:stream_specifier] codec_tag (output,per-stream)
Force a tag/fourcc for matching streams.
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