Synopsis
********

The generic syntax is:

     avconv [global options] [[infile options][-i INFILE]]... {[outfile options] OUTFILE}...

Description
***********

avconv is a very fast video and audio converter that can also grab from a live audio/video source. It can also convert between arbitrary sample rates and resize video on the fly with a high quality polyphase filter.

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.

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

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

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

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

  * To 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:

          avconv -r 1 -i input.m2v -r 24 output.avi

The format option may be needed for raw input files.

Stream selection
****************

By default avconv tries to pick the "best" stream of each type present in input files and add them to each output file. For video, this means the highest resolution, for audio the highest channel count. For subtitle it's simply the first subtitle stream.

You can disable some of those defaults by using -vn/-an/-sn options. For full manual control, use the -map option, which disables the defaults just described.

Options
*******

     [file avtools-common-opts.texi not included]

Main options
============

-f FMT (input/output)
     Force input or output file format. The format is normally autodetected for input files and guessed from file extension for output files, so this option is not needed in most cases.

-i FILENAME (input)
     input file name

-y (global)
     Overwrite output files without asking.

-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 reencoded.

     For example

          avconv -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

          avconv -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 (output)
     Stop writing the output after its duration reaches DURATION. DURATION may be a number in seconds, or in hh:mm:ss[.xxx] form.

-fs LIMIT_SIZE (output)
     Set the file size limit.

-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.

-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.

-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 or chapters. 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:

          avconv -i in.avi -metadata title="my title" out.flv

     To set the language of the second stream:

          avconv -i INPUT -metadata:s:1 language=eng OUTPUT

-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

-dframes NUMBER (output)
     Set the number of data frames to record. This is an alias for -frames:d.

-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 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).

-pre[:STREAM_SPECIFIER] PRESET_NAME (output,per-stream)
     Specify the preset for matching stream(s).

-stats (global)
     Print encoding progress/statistics. On by default.

-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).

-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':

          avconv -dump_attachment:t:0 out.ttf INPUT

     To extract all attachments to files determined by the filename tag:

          avconv -dump_attachment:t "" 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 record. This is an alias for -frames:v.

-r[:STREAM_SPECIFIER] FPS (input/output,per-stream)
     Set frame rate (Hz value, fraction or abbreviation), (default = 25).

-s[:STREAM_SPECIFIER] SIZE (input/output,per-stream)
     Set frame size. The format is wxh (ffserver default = 160x128, avconv default = same as source). The following abbreviations are recognized:

     sqcif
          128x96

     qcif
          176x144

     cif
          352x288

     4cif
          704x576

     16cif
          1408x1152

     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[: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.

-vn (output)
     Disable video recording.

-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.

-maxrate BITRATE
     Set max video bitrate (in bit/s). Requires -bufsize to be set.

-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.

-bufsize SIZE
     Set video buffer verifier buffer size (in bits).

-vcodec CODEC (output)
     Set the video codec. This is an alias for -codec:v.

-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.

-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

-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.

-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.

-sws_flags FLAGS (input/output)
     Set SwScaler flags.

-g GOP_SIZE
     Set the group of pictures size.

-vdt N
     Discard threshold.

-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) (range 0.0 - 1.0)

-qcomp COMPRESSION
     video quantizer scale compression (VBR) (default 0.5). Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0

-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:

          avconv -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 (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

-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)

-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 avconv).

     1
          FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.

     2
          FF_MB_DECISION_RD: rate distortion

-bug PARAM
     Work around encoder bugs that are not auto-detected.

-strict STRICTNESS
     How strictly to follow the standards.

-deinterlace
     Deinterlace pictures.

-vstats
     Dump video coding statistics to vstats_HHMMSS.log.

-vstats_file FILE
     Dump video coding statistics to FILE.

-top[:STREAM_SPECIFIER] N (output,per-stream)
     top=1/bottom=0/auto=-1 field first

-dc PRECISION
     Intra_dc_precision.

-vtag FOURCC/TAG (output)
     Force video tag/fourcc. This is an alias for -tag:v.

-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.

Audio Options
=============

-aframes NUMBER (output)
     Set the number of audio frames to record. This is an alias for -frames:a.

-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 (output)
     Disable audio recording.

-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 -help sample_fmts to get a list of supported sample formats.

Advanced Audio options:
=======================

-atag FOURCC/TAG (output)
     Force audio tag/fourcc. This is an alias for -tag:a.

-audio_service_type TYPE
     Set the type of service that the audio stream contains.

     ma
          Main Audio Service (default)

     ef
          Effects

     vi
          Visually Impaired

     hi
          Hearing Impaired

     di
          Dialogue

     co
          Commentary

     em
          Emergency

     vo
          Voice Over

     ka
          Karaoke

Subtitle options:
=================

-scodec CODEC (input/output)
     Set the subtitle codec. This is an alias for -codec:s.

-sn (output)
     Disable subtitle recording.

Audio/Video grab options
========================

-isync (global)
     Synchronize read on input.

Advanced options
================

-map [-]INPUT_FILE_ID[:STREAM_SPECIFIER][,SYNC_FILE_ID[:STREAM_SPECIFIER]] (output)

     Designate one or more input streams as a source for the output file. Each input stream is identified by the input file index INPUT_FILE_ID and the input stream index INPUT_STREAM_ID within the input file. Both indices start at 0. If specified, SYNC_FILE_ID:STREAM_SPECIFIER sets which input stream is used as a presentation sync reference.

     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.

     For example, to map ALL streams from the first input file to output

          avconv -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:

          avconv -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:

          avconv -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:

          avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT

     To map all the streams except the second audio, use negative mappings

          avconv -i INPUT -map 0 -map -0:a:1 OUTPUT

     Note that using this option disables the default mappings for this output file.

-map_metadata[:METADATA_TYPE][:INDEX] INFILE[:METADATA_TYPE][:INDEX] (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_TYPE parameters specify, which metadata to copy - (g)lobal (i.e. metadata that applies to the whole file), per-(s)tream, per-(c)hapter or per-(p)rogram. All metadata specifiers other than global must be followed by the stream/chapter/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:

          avconv -i in.ogg -map_metadata 0:s:0 out.mp3

-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.

-debug
     Print specific debug info.

-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.

-timelimit DURATION (global)
     Exit after avconv has been running for DURATION seconds.

-dump (global)
     Dump each input packet to stderr.

-hex (global)
     When dumping packets, also dump the payload.

-ps SIZE
     Set RTP payload size in bytes.

-re (input)
     Read input at native frame rate. Mainly used to simulate a grab device.

-threads COUNT
     Thread count.

-vsync PARAMETER
     Video sync method.

     0
          Each frame is passed with its timestamp from the demuxer to the muxer.

     1
          Frames will be duplicated and dropped to achieve exactly the requested constant framerate.

     2
          Frames are passed through with their timestamp or dropped so as to prevent 2 frames from having the same timestamp.

     -1
          Chooses between 1 and 2 depending on muxer capabilities. This is the default method.

     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.

-copytb
     Copy input stream time base from input to output when stream copying.

-shortest
     Finish encoding when the shortest input stream ends.

-dts_delta_threshold
     Timestamp discontinuity delta threshold.

-muxdelay SECONDS (input)
     Set the maximum demux-decode delay.

-muxpreload SECONDS (input)
     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:

          avconv -i infile -streamid 0:33 -streamid 1:36 out.ts

-bsf[:STREAM_SPECIFIER] BITSTREAM_FILTERS (output,per-stream)
     Set bitstream filters for matching streams. BISTREAM_FILTERS is a comma-separated list of bitstream filters. Use the -bsfs option to get the list of bitstream filters.

          avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264

          avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt

-tag[:STREAM_SPECIFIER] CODEC_TAG (output,per-stream)
     Force a tag/fourcc for matching streams.

Tips
****

  * For streaming at very low bitrate application, use a low frame rate and a small GOP size. This is especially true for RealVideo where the Linux player does not seem to be very fast, so it can miss frames. An example is:

          avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm

  * The parameter 'q' which is displayed while encoding is the current quantizer. The value 1 indicates that a very good quality could be achieved. The value 31 indicates the worst quality. If q=31 appears too often, it means that the encoder cannot compress enough to meet your bitrate. You must either increase the bitrate, decrease the frame rate or decrease the frame size.

  * If your computer is not fast enough, you can speed up the compression at the expense of the compression ratio. You can use '-me zero' to speed up motion estimation, and '-intra' to disable motion estimation completely (you have only I-frames, which means it is about as good as JPEG compression).

  * To have very low audio bitrates, reduce the sampling frequency (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).

  * To have a constant quality (but a variable bitrate), use the option '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst quality).

Examples
********

Preset files
============

A preset file contains a sequence of OPTION=VALUE pairs, one for each line, specifying a sequence of options which can be specified also on the command line. Lines starting with the hash ('#') character are ignored and are used to provide comments. Empty lines are also ignored. Check the presets directory in the Libav source tree for examples.

Preset files are specified with the pre option, this option takes a preset name as input.  Avconv searches for a file named PRESET_NAME.avpreset in the directories $AVCONV_DATADIR (if set), and $HOME/.avconv, and in the data directory defined at configuration time (usually $PREFIX/share/avconv) in that order.  For example, if the argument is libx264-max, it will search for the file libx264-max.avpreset.

Video and Audio grabbing
========================

If you specify the input format and device then avconv can grab video and audio directly.

     avconv -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 avconv with any TV viewer such as xawtv (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 avconv via

     avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg

0.0 is display.screen number of your X11 server, same as the DISPLAY environment variable.

     avconv -f x11grab -s cif -r 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 avconv:

Examples:

  * You can use YUV files as input:

          avconv -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 avconv cannot guess it.

  * You can input from a raw YUV420P file:

          avconv -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:

          avconv -i mydivx.avi hugefile.yuv

  * You can set several input files and output files:

          avconv -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:

          avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2

     Converts a.wav to MPEG audio at 22050 Hz sample rate.

  * You can encode to several formats at the same time and define a mapping from input stream to output streams:

          avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 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.

  * You can transcode decrypted VOBs:

          avconv -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 avconv -formats.

  * You can extract images from a video, or create a video from many images:

     For extracting images from a video:

          avconv -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 -vframes or -t option, or in combination with -ss to start extracting from a certain point in time.

     For creating a video from many images:

          avconv -f image2 -i foo-%03d.jpeg -r 12 -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.

  * You can put many streams of the same type in the output:

          avconv -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut

     The resulting output file test12.avi will contain first four streams from the input file in reverse order.

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