\input texinfo @c -*- texinfo -*- @settitle avconv Documentation @titlepage @center @titlefont{avconv Documentation} @end titlepage @top @contents @chapter Synopsis The generic syntax is: @example @c man begin SYNOPSIS avconv [global options] [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}... @c man end @end example @chapter Description @c man begin 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. @itemize @item To set the video bitrate of the output file to 64kbit/s: @example avconv -i input.avi -b 64k output.avi @end example @item To force the frame rate of the output file to 24 fps: @example avconv -i input.avi -r 24 output.avi @end example @item 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: @example avconv -r 1 -i input.m2v -r 24 output.avi @end example @end itemize The format option may be needed for raw input files. @c man end DESCRIPTION @chapter Stream selection @c man begin 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 @code{-vn/-an/-sn} options. For full manual control, use the @code{-map} option, which disables the defaults just described. @c man end STREAM SELECTION @chapter Options @c man begin OPTIONS @include avtools-common-opts.texi @section Main options @table @option @item -f @var{fmt} (@emph{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. @item -i @var{filename} (@emph{input}) input file name @item -y (@emph{global}) Overwrite output files without asking. @item -c[:@var{stream_specifier}] @var{codec} (@emph{input/output,per-stream}) @itemx -codec[:@var{stream_specifier}] @var{codec} (@emph{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. @var{codec} is the name of a decoder/encoder or a special value @code{copy} (output only) to indicate that the stream is not to be reencoded. For example @example avconv -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT @end example encodes all video streams with libx264 and copies all audio streams. For each stream, the last matching @code{c} option is applied, so @example avconv -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT @end example 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. @item -t @var{duration} (@emph{output}) Stop writing the output after its duration reaches @var{duration}. @var{duration} may be a number in seconds, or in @code{hh:mm:ss[.xxx]} form. @item -fs @var{limit_size} (@emph{output}) Set the file size limit. @item -ss @var{position} (@emph{input/output}) When used as an input option (before @code{-i}), seeks in this input file to @var{position}. When used as an output option (before an output filename), decodes but discards input until the timestamps reach @var{position}. This is slower, but more accurate. @var{position} may be either in seconds or in @code{hh:mm:ss[.xxx]} form. @item -itsoffset @var{offset} (@emph{input}) Set the input time offset in seconds. @code{[-]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 @var{offset} seconds. @item -metadata[:metadata_specifier] @var{key}=@var{value} (@emph{output,per-metadata}) Set a metadata key/value pair. An optional @var{metadata_specifier} may be given to set metadata on streams or chapters. See @code{-map_metadata} documentation for details. This option overrides metadata set with @code{-map_metadata}. It is also possible to delete metadata by using an empty value. For example, for setting the title in the output file: @example avconv -i in.avi -metadata title="my title" out.flv @end example To set the language of the second stream: @example avconv -i INPUT -metadata:s:1 language=eng OUTPUT @end example @item -v @var{number} (@emph{global}) This option is deprecated and has no effect, use -loglevel to set verbosity level. @item -target @var{type} (@emph{output}) Specify target file type (@code{vcd}, @code{svcd}, @code{dvd}, @code{dv}, @code{dv50}). @var{type} may be prefixed with @code{pal-}, @code{ntsc-} or @code{film-} to use the corresponding standard. All the format options (bitrate, codecs, buffer sizes) are then set automatically. You can just type: @example avconv -i myfile.avi -target vcd /tmp/vcd.mpg @end example Nevertheless you can specify additional options as long as you know they do not conflict with the standard, as in: @example avconv -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg @end example @item -dframes @var{number} (@emph{output}) Set the number of data frames to record. This is an alias for @code{-frames:d}. @item -frames[:@var{stream_specifier}] @var{framecount} (@emph{output,per-stream}) Stop writing to the stream after @var{framecount} frames. @item -q[:@var{stream_specifier}] @var{q} (@emph{output,per-stream}) @itemx -qscale[:@var{stream_specifier}] @var{q} (@emph{output,per-stream}) Use fixed quality scale (VBR). The meaning of @var{q} is codec-dependent. @item -filter[:@var{stream_specifier}] @var{filter_graph} @var{filter_graph} is a description of the filter graph to apply to the stream. Use @code{-filters} to show all the available filters (including also sources and sinks). @item -stats (@emph{global}) Print encoding progress/statistics. On by default. @end table @section Video Options @table @option @item -vframes @var{number} (@emph{output}) Set the number of video frames to record. This is an alias for @code{-frames:v}. @item -r[:@var{stream_specifier}] @var{fps} (@emph{input/output,per-stream}) Set frame rate (Hz value, fraction or abbreviation), (default = 25). @item -s[:@var{stream_specifier}] @var{size} (@emph{input/output,per-stream}) Set frame size. The format is @samp{wxh} (avserver default = 160x128, avconv default = same as source). The following abbreviations are recognized: @table @samp @item sqcif 128x96 @item qcif 176x144 @item cif 352x288 @item 4cif 704x576 @item 16cif 1408x1152 @item qqvga 160x120 @item qvga 320x240 @item vga 640x480 @item svga 800x600 @item xga 1024x768 @item uxga 1600x1200 @item qxga 2048x1536 @item sxga 1280x1024 @item qsxga 2560x2048 @item hsxga 5120x4096 @item wvga 852x480 @item wxga 1366x768 @item wsxga 1600x1024 @item wuxga 1920x1200 @item woxga 2560x1600 @item wqsxga 3200x2048 @item wquxga 3840x2400 @item whsxga 6400x4096 @item whuxga 7680x4800 @item cga 320x200 @item ega 640x350 @item hd480 852x480 @item hd720 1280x720 @item hd1080 1920x1080 @end table @item -aspect[:@var{stream_specifier}] @var{aspect} (@emph{output,per-stream}) Set the video display aspect ratio specified by @var{aspect}. @var{aspect} can be a floating point number string, or a string of the form @var{num}:@var{den}, where @var{num} and @var{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. @item -vn (@emph{output}) Disable video recording. @item -bt @var{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. @item -maxrate @var{bitrate} Set max video bitrate (in bit/s). Requires -bufsize to be set. @item -minrate @var{bitrate} Set min video bitrate (in bit/s). Most useful in setting up a CBR encode: @example avconv -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v @end example It is of little use elsewise. @item -bufsize @var{size} Set video buffer verifier buffer size (in bits). @item -vcodec @var{codec} (@emph{output}) Set the video codec. This is an alias for @code{-codec:v}. @item -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. @item -pass @var{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: @example 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 @end example @item -passlogfile @var{prefix} (@emph{global}) Set two-pass log file name prefix to @var{prefix}, the default file name prefix is ``av2pass''. The complete file name will be @file{PREFIX-N.log}, where N is a number specific to the output stream. @item -vf @var{filter_graph} (@emph{output}) @var{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 @code{-filter:v}. @end table @section Advanced Video Options @table @option @item -pix_fmt[:@var{stream_specifier}] @var{format} (@emph{input/output,per-stream}) Set pixel format. Use @code{-pix_fmts} to show all the supported pixel formats. @item -sws_flags @var{flags} (@emph{input/output}) Set SwScaler flags. @item -g @var{gop_size} Set the group of pictures size. @item -vdt @var{n} Discard threshold. @item -qmin @var{q} minimum video quantizer scale (VBR) @item -qmax @var{q} maximum video quantizer scale (VBR) @item -qdiff @var{q} maximum difference between the quantizer scales (VBR) @item -qblur @var{blur} video quantizer scale blur (VBR) (range 0.0 - 1.0) @item -qcomp @var{compression} video quantizer scale compression (VBR) (default 0.5). Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0 @item -lmin @var{lambda} minimum video lagrange factor (VBR) @item -lmax @var{lambda} max video lagrange factor (VBR) @item -mblmin @var{lambda} minimum macroblock quantizer scale (VBR) @item -mblmax @var{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: @example avconv -i src.ext -lmax 21*QP2LAMBDA dst.ext @end example @item -rc_init_cplx @var{complexity} initial complexity for single pass encoding @item -b_qfactor @var{factor} qp factor between P- and B-frames @item -i_qfactor @var{factor} qp factor between P- and I-frames @item -b_qoffset @var{offset} qp offset between P- and B-frames @item -i_qoffset @var{offset} qp offset between P- and I-frames @item -rc_eq @var{equation} Set rate control equation (see section "Expression Evaluation") (default = @code{tex^qComp}). When computing the rate control equation expression, besides the standard functions defined in the section "Expression Evaluation", the following functions are available: @table @var @item bits2qp(bits) @item qp2bits(qp) @end table and the following constants are available: @table @var @item iTex @item pTex @item tex @item mv @item fCode @item iCount @item mcVar @item var @item isI @item isP @item isB @item avgQP @item qComp @item avgIITex @item avgPITex @item avgPPTex @item avgBPTex @item avgTex @end table @item -rc_override[:@var{stream_specifier}] @var{override} (@emph{output,per-stream}) rate control override for specific intervals @item -me_method @var{method} Set motion estimation method to @var{method}. Available methods are (from lowest to best quality): @table @samp @item zero Try just the (0, 0) vector. @item phods @item log @item x1 @item hex @item umh @item epzs (default method) @item full exhaustive search (slow and marginally better than epzs) @end table @item -er @var{n} Set error resilience to @var{n}. @table @samp @item 1 FF_ER_CAREFUL (default) @item 2 FF_ER_COMPLIANT @item 3 FF_ER_AGGRESSIVE @item 4 FF_ER_VERY_AGGRESSIVE @end table @item -ec @var{bit_mask} Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of the following values: @table @samp @item 1 FF_EC_GUESS_MVS (default = enabled) @item 2 FF_EC_DEBLOCK (default = enabled) @end table @item -bf @var{frames} Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4). @item -mbd @var{mode} macroblock decision @table @samp @item 0 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in avconv). @item 1 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits. @item 2 FF_MB_DECISION_RD: rate distortion @end table @item -bug @var{param} Work around encoder bugs that are not auto-detected. @item -strict @var{strictness} How strictly to follow the standards. @item -deinterlace Deinterlace pictures. @item -vstats Dump video coding statistics to @file{vstats_HHMMSS.log}. @item -vstats_file @var{file} Dump video coding statistics to @var{file}. @item -top[:@var{stream_specifier}] @var{n} (@emph{output,per-stream}) top=1/bottom=0/auto=-1 field first @item -dc @var{precision} Intra_dc_precision. @item -vtag @var{fourcc/tag} (@emph{output}) Force video tag/fourcc. This is an alias for @code{-tag:v}. @item -qphist (@emph{global}) Show QP histogram. @item -force_key_frames[:@var{stream_specifier}] @var{time}[,@var{time}...] (@emph{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. @end table @section Audio Options @table @option @item -aframes @var{number} (@emph{output}) Set the number of audio frames to record. This is an alias for @code{-frames:a}. @item -ar[:@var{stream_specifier}] @var{freq} (@emph{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. @item -aq @var{q} (@emph{output}) Set the audio quality (codec-specific, VBR). This is an alias for -q:a. @item -ac[:@var{stream_specifier}] @var{channels} (@emph{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. @item -an (@emph{output}) Disable audio recording. @item -acodec @var{codec} (@emph{input/output}) Set the audio codec. This is an alias for @code{-codec:a}. @item -sample_fmt[:@var{stream_specifier}] @var{sample_fmt} (@emph{output,per-stream}) Set the audio sample format. Use @code{-help sample_fmts} to get a list of supported sample formats. @end table @section Advanced Audio options: @table @option @item -atag @var{fourcc/tag} (@emph{output}) Force audio tag/fourcc. This is an alias for @code{-tag:a}. @item -audio_service_type @var{type} Set the type of service that the audio stream contains. @table @option @item ma Main Audio Service (default) @item ef Effects @item vi Visually Impaired @item hi Hearing Impaired @item di Dialogue @item co Commentary @item em Emergency @item vo Voice Over @item ka Karaoke @end table @end table @section Subtitle options: @table @option @item -scodec @var{codec} (@emph{input/output}) Set the subtitle codec. This is an alias for @code{-codec:s}. @item -sn (@emph{output}) Disable subtitle recording. @end table @section Audio/Video grab options @table @option @item -isync (@emph{global}) Synchronize read on input. @end table @section Advanced options @table @option @item -map [-]@var{input_file_id}[:@var{stream_specifier}][,@var{sync_file_id}[:@var{stream_specifier}]] (@emph{output}) Designate one or more input streams as a source for the output file. Each input stream is identified by the input file index @var{input_file_id} and the input stream index @var{input_stream_id} within the input file. Both indices start at 0. If specified, @var{sync_file_id}:@var{stream_specifier} sets which input stream is used as a presentation sync reference. The first @code{-map} option on the command line specifies the source for output stream 0, the second @code{-map} option specifies the source for output stream 1, etc. A @code{-} 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 @example avconv -i INPUT -map 0 output @end example 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 @code{-map} to select which streams to place in an output file. For example: @example avconv -i INPUT -map 0:1 out.wav @end example will map the input stream in @file{INPUT} identified by "0:1" to the (single) output stream in @file{out.wav}. For example, to select the stream with index 2 from input file @file{a.mov} (specified by the identifier "0:2"), and stream with index 6 from input @file{b.mov} (specified by the identifier "1:6"), and copy them to the output file @file{out.mov}: @example avconv -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov @end example To select all video and the third audio stream from an input file: @example avconv -i INPUT -map 0:v -map 0:a:2 OUTPUT @end example To map all the streams except the second audio, use negative mappings @example avconv -i INPUT -map 0 -map -0:a:1 OUTPUT @end example Note that using this option disables the default mappings for this output file. @item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}] (@emph{output,per-metadata}) Set metadata information of the next output file from @var{infile}. Note that those are file indices (zero-based), not filenames. Optional @var{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: @example avconv -i in.ogg -map_metadata 0:s:0 out.mp3 @end example @item -map_chapters @var{input_file_index} (@emph{output}) Copy chapters from input file with index @var{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. @item -debug Print specific debug info. @item -benchmark (@emph{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. @item -timelimit @var{duration} (@emph{global}) Exit after avconv has been running for @var{duration} seconds. @item -dump (@emph{global}) Dump each input packet to stderr. @item -hex (@emph{global}) When dumping packets, also dump the payload. @item -ps @var{size} Set RTP payload size in bytes. @item -re (@emph{input}) Read input at native frame rate. Mainly used to simulate a grab device. @item -threads @var{count} Thread count. @item -vsync @var{parameter} Video sync method. @table @option @item 0 Each frame is passed with its timestamp from the demuxer to the muxer. @item 1 Frames will be duplicated and dropped to achieve exactly the requested constant framerate. @item 2 Frames are passed through with their timestamp or dropped so as to prevent 2 frames from having the same timestamp. @item -1 Chooses between 1 and 2 depending on muxer capabilities. This is the default method. @end table 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. @item -async @var{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. @item -copyts Copy timestamps from input to output. @item -copytb Copy input stream time base from input to output when stream copying. @item -shortest Finish encoding when the shortest input stream ends. @item -dts_delta_threshold Timestamp discontinuity delta threshold. @item -muxdelay @var{seconds} (@emph{input}) Set the maximum demux-decode delay. @item -muxpreload @var{seconds} (@emph{input}) Set the initial demux-decode delay. @item -streamid @var{output-stream-index}:@var{new-value} (@emph{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: @example avconv -i infile -streamid 0:33 -streamid 1:36 out.ts @end example @item -bsf[:@var{stream_specifier}] @var{bitstream_filters} (@emph{output,per-stream}) Set bitstream filters for matching streams. @var{bistream_filters} is a comma-separated list of bitstream filters. Use the @code{-bsfs} option to get the list of bitstream filters. @example avconv -i h264.mp4 -c:v copy -vbsf h264_mp4toannexb -an out.h264 @end example @example avconv -i file.mov -an -vn -sbsf mov2textsub -c:s copy -f rawvideo sub.txt @end example @item -tag[:@var{stream_specifier}] @var{codec_tag} (@emph{output,per-stream}) Force a tag/fourcc for matching streams. @end table @c man end OPTIONS @chapter Tips @c man begin TIPS @itemize @item 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: @example avconv -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm @end example @item 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. @item 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). @item To have very low audio bitrates, reduce the sampling frequency (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3). @item 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). @end itemize @c man end TIPS @chapter Examples @c man begin EXAMPLES @section Video and Audio grabbing If you specify the input format and device then avconv can grab video and audio directly. @example avconv -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg @end example Note that you must activate the right video source and channel before launching avconv with any TV viewer such as @uref{http://linux.bytesex.org/xawtv/, xawtv} by Gerd Knorr. You also have to set the audio recording levels correctly with a standard mixer. @section X11 grabbing Grab the X11 display with avconv via @example avconv -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg @end example 0.0 is display.screen number of your X11 server, same as the DISPLAY environment variable. @example avconv -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg @end example 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. @section Video and Audio file format conversion Any supported file format and protocol can serve as input to avconv: Examples: @itemize @item You can use YUV files as input: @example avconv -i /tmp/test%d.Y /tmp/out.mpg @end example It will use the files: @example /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V, /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc... @end example 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 @option{-s} option if avconv cannot guess it. @item You can input from a raw YUV420P file: @example avconv -i /tmp/test.yuv /tmp/out.avi @end example 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. @item You can output to a raw YUV420P file: @example avconv -i mydivx.avi hugefile.yuv @end example @item You can set several input files and output files: @example avconv -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg @end example Converts the audio file a.wav and the raw YUV video file a.yuv to MPEG file a.mpg. @item You can also do audio and video conversions at the same time: @example avconv -i /tmp/a.wav -ar 22050 /tmp/a.mp2 @end example Converts a.wav to MPEG audio at 22050 Hz sample rate. @item You can encode to several formats at the same time and define a mapping from input stream to output streams: @example avconv -i /tmp/a.wav -map 0:a -b 64k /tmp/a.mp2 -map 0:a -b 128k /tmp/b.mp2 @end example 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. @item You can transcode decrypted VOBs: @example 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 @end example 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 @code{--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 @code{avconv -formats}. @item You can extract images from a video, or create a video from many images: For extracting images from a video: @example avconv -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg @end example This will extract one video frame per second from the video and will output them in files named @file{foo-001.jpeg}, @file{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: @example avconv -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi @end example The syntax @code{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. @item You can put many streams of the same type in the output: @example avconv -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut @end example The resulting output file @file{test12.avi} will contain first four streams from the input file in reverse order. @end itemize @c man end EXAMPLES @include eval.texi @include encoders.texi @include demuxers.texi @include muxers.texi @include indevs.texi @include outdevs.texi @include protocols.texi @include bitstream_filters.texi @include filters.texi @include metadata.texi @ignore @setfilename avconv @settitle avconv video converter @c man begin SEEALSO avplay(1), avprobe(1), avserver(1) and the Libav HTML documentation @c man end @c man begin AUTHORS The Libav developers @c man end @end ignore @bye