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AVPROBE(1)                                                          AVPROBE(1)

avprobe - avprobe media prober

       avprobe [options] [input_file]

       avprobe gathers information from multimedia streams and prints it in
       human- and machine-readable fashion.

       For example it can be used to check the format of the container used by
       a multimedia stream and the format and type of each media stream
       contained in it.

       If a filename is specified in input, avprobe will try to open and probe
       the file content. If the file cannot be opened or recognized as a
       multimedia file, a positive exit code is returned.

       avprobe may be employed both as a standalone application or in
       combination with a textual filter, which may perform more sophisticated
       processing, e.g. statistical processing or plotting.

       Options are used to list some of the formats supported by avprobe or
       for specifying which information to display, and for setting how
       avprobe will show it.

       avprobe output is designed to be easily parsable by any INI or JSON
       parsers.

       All the numerical options, if not specified otherwise, accept in input
       a string representing a number, which may contain one of the SI unit
       prefixes, for example 'K', 'M', 'G'.  If 'i' is appended after the
       prefix, binary prefixes are used, which are based on powers of 1024
       instead of powers of 1000.  The 'B' postfix multiplies the value by 8,
       and can be appended after a unit prefix or used alone. This allows
       using for example 'KB', 'MiB', 'G' and 'B' as number postfix.

       Options which do not take arguments are boolean options, and set the
       corresponding value to true. They can be set to false by prefixing with
       "no" the option name, for example using "-nofoo" in the command line
       will set to false the boolean option with name "foo".

   Stream specifiers
       Some options are applied per-stream, e.g. bitrate or codec. Stream
       specifiers are used to precisely specify which stream(s) does a given
       option belong to.

       A stream specifier is a string generally appended to the option name
       and separated from it by a colon. E.g. "-codec:a:1 ac3" option contains
       "a:1" stream specifer, which matches the second audio stream. Therefore
       it would select the ac3 codec for the second audio stream.

       A stream specifier can match several stream, the option is then applied
       to all of them. E.g. the stream specifier in "-b:a 128k" matches all
       audio streams.

       An empty stream specifier matches all streams, for example "-codec
       copy" or "-codec: copy" would copy all the streams without reencoding.

       Possible forms of stream specifiers are:

       stream_index
           Matches the stream with this index. E.g. "-threads:1 4" would set
           the thread count for the second stream to 4.

       stream_type[:stream_index]
           stream_type is one of: 'v' for video, 'a' for audio, 's' for
           subtitle, 'd' for data and 't' for attachments. If stream_index is
           given, then matches stream number stream_index of this type.
           Otherwise matches all streams of this type.

       p:program_id[:stream_index]
           If stream_index is given, then matches stream number stream_index
           in program with id program_id. Otherwise matches all streams in
           this program.

       i:stream_id
           Match the stream by stream id (e.g. PID in MPEG-TS container).

       m:key[:value]
           Matches streams with the metadata tag key having the specified
           value. If value is not given, matches streams that contain the
           given tag with any value.

           Note that in avconv, matching by metadata will only work properly
           for input files.

   Generic options
       These options are shared amongst the av* tools.

       -L  Show license.

       -h, -?, -help, --help [arg]
           Show help. An optional parameter may be specified to print help
           about a specific item.

           Possible values of arg are:

           decoder=decoder_name
               Print detailed information about the decoder named
               decoder_name. Use the -decoders option to get a list of all
               decoders.

           encoder=encoder_name
               Print detailed information about the encoder named
               encoder_name. Use the -encoders option to get a list of all
               encoders.

           demuxer=demuxer_name
               Print detailed information about the demuxer named
               demuxer_name. Use the -formats option to get a list of all
               demuxers and muxers.

           muxer=muxer_name
               Print detailed information about the muxer named muxer_name.
               Use the -formats option to get a list of all muxers and
               demuxers.

           filter=filter_name
               Print detailed information about the filter name filter_name.
               Use the -filters option to get a list of all filters.

       -version
           Show version.

       -formats
           Show available formats.

           The fields preceding the format names have the following meanings:

           D   Decoding available

           E   Encoding available

       -codecs
           Show all codecs known to libavcodec.

           Note that the term 'codec' is used throughout this documentation as
           a shortcut for what is more correctly called a media bitstream
           format.

       -decoders
           Show available decoders.

       -encoders
           Show all available encoders.

       -bsfs
           Show available bitstream filters.

       -protocols
           Show available protocols.

       -filters
           Show available libavfilter filters.

       -pix_fmts
           Show available pixel formats.

       -sample_fmts
           Show available sample formats.

       -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:

           quiet
           panic
           fatal
           error
           warning
           info
           verbose
           debug

           By default the program logs to stderr, if coloring is supported by
           the terminal, colors are used to mark errors and warnings. Log
           coloring can be disabled setting the environment variable
           AV_LOG_FORCE_NOCOLOR or NO_COLOR, or can be forced setting the
           environment variable AV_LOG_FORCE_COLOR.  The use of the
           environment variable NO_COLOR is deprecated and will be dropped in
           a following Libav version.

       -cpuflags mask (global)
           Set a mask that's applied to autodetected CPU flags. This option is
           intended for testing. Do not use it unless you know what you're
           doing.

   AVOptions
       These options are provided directly by the libavformat, libavdevice and
       libavcodec libraries. To see the list of available AVOptions, use the
       -help option. They are separated into two categories:

       generic
           These options can be set for any container, codec or device.
           Generic options are listed under AVFormatContext options for
           containers/devices and under AVCodecContext options for codecs.

       private
           These options are specific to the given container, device or codec.
           Private options are listed under their corresponding
           containers/devices/codecs.

       For example to write an ID3v2.3 header instead of a default ID3v2.4 to
       an MP3 file, use the id3v2_version private option of the MP3 muxer:

               avconv -i input.flac -id3v2_version 3 out.mp3

       All codec AVOptions are obviously per-stream, so the chapter on stream
       specifiers applies to them

       Note -nooption syntax cannot be used for boolean AVOptions, use -option
       0/-option 1.

       Note2 old undocumented way of specifying per-stream AVOptions by
       prepending v/a/s to the options name is now obsolete and will be
       removed soon.

   Codec AVOptions
       -b[:stream_specifier] integer (output,audio,video)
           set bitrate (in bits/s)

       -bt[:stream_specifier] integer (output,video)
           Set video bitrate tolerance (in bits/s). 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
           minimum/maximum bitrate. Lowering tolerance too much has an adverse
           effect on quality.

       -flags[:stream_specifier] flags (input/output,audio,video)
           Possible values:

           unaligned
               allow decoders to produce unaligned output

           mv4 use four motion vectors per macroblock (MPEG-4)

           qpel
               use 1/4-pel motion compensation

           loop
               use loop filter

           qscale
               use fixed qscale

           gmc use gmc

           mv0 always try a mb with mv=<0,0>

           input_preserved
           pass1
               use internal 2-pass ratecontrol in first  pass mode

           pass2
               use internal 2-pass ratecontrol in second pass mode

           gray
               only decode/encode grayscale

           emu_edge
               do not draw edges

           psnr
               error[?] variables will be set during encoding

           truncated
           naq normalize adaptive quantization

           ildct
               use interlaced DCT

           low_delay
               force low delay

           global_header
               place global headers in extradata instead of every keyframe

           bitexact
               use only bitexact functions (except (I)DCT)

           aic H.263 advanced intra coding / MPEG-4 AC prediction

           ilme
               interlaced motion estimation

           cgop
               closed GOP

           output_corrupt
               Output even potentially corrupted frames

       -me_method[:stream_specifier] integer (output,video)
           set motion estimation method

           Possible values:

           zero
               zero motion estimation (fastest)

           full
               full motion estimation (slowest)

           epzs
               EPZS motion estimation (default)

           esa esa motion estimation (alias for full)

           tesa
               tesa motion estimation

           dia diamond motion estimation (alias for EPZS)

           log log motion estimation

           phods
               phods motion estimation

           x1  X1 motion estimation

           hex hex motion estimation

           umh umh motion estimation

       -g[:stream_specifier] integer (output,video)
           set the group of picture (GOP) size

       -ar[:stream_specifier] integer (input/output,audio)
           set audio sampling rate (in Hz)

       -ac[:stream_specifier] integer (input/output,audio)
           set number of audio channels

       -cutoff[:stream_specifier] integer (output,audio)
           set cutoff bandwidth

       -frame_size[:stream_specifier] integer (output,audio)
       -qcomp[:stream_specifier] float (output,video)
           video quantizer scale compression (VBR). Constant of ratecontrol
           equation. Recommended range for default rc_eq: 0.0-1.0

       -qblur[:stream_specifier] float (output,video)
           video quantizer scale blur (VBR)

       -qmin[:stream_specifier] integer (output,video)
           minimum video quantizer scale (VBR)

       -qmax[:stream_specifier] integer (output,video)
           maximum video quantizer scale (VBR)

       -qdiff[:stream_specifier] integer (output,video)
           maximum difference between the quantizer scales (VBR)

       -bf[:stream_specifier] integer (output,video)
           use 'frames' B frames

       -b_qfactor[:stream_specifier] float (output,video)
           QP factor between P- and B-frames

       -rc_strategy[:stream_specifier] integer (output,video)
           ratecontrol method

       -b_strategy[:stream_specifier] integer (output,video)
           strategy to choose between I/P/B-frames

       -ps[:stream_specifier] integer (output,video)
           RTP payload size in bytes

       -bug[:stream_specifier] flags (input,video)
           work around not autodetected encoder bugs

           Possible values:

           autodetect
           old_msmpeg4
               some old lavc-generated MSMPEG4v3 files (no autodetection)

           xvid_ilace
               Xvid interlacing bug (autodetected if FOURCC == XVIX)

           ump4
               (autodetected if FOURCC == UMP4)

           no_padding
               padding bug (autodetected)

           amv
           ac_vlc
               illegal VLC bug (autodetected per FOURCC)

           qpel_chroma
           std_qpel
               old standard qpel (autodetected per FOURCC/version)

           qpel_chroma2
           direct_blocksize
               direct-qpel-blocksize bug (autodetected per FOURCC/version)

           edge
               edge padding bug (autodetected per FOURCC/version)

           hpel_chroma
           dc_clip
           ms  work around various bugs in Microsoft's broken decoders

           trunc
               truncated frames

       -strict[:stream_specifier] integer (input/output,audio,video)
           how strictly to follow the standards

           Possible values:

           very
               strictly conform to a older more strict version of the spec or
               reference software

           strict
               strictly conform to all the things in the spec no matter what
               the consequences

           normal
           unofficial
               allow unofficial extensions

           experimental
               allow non-standardized experimental things

       -b_qoffset[:stream_specifier] float (output,video)
           QP offset between P- and B-frames

       -err_detect[:stream_specifier] flags (input,audio,video)
           set error detection flags

           Possible values:

           crccheck
               verify embedded CRCs

           bitstream
               detect bitstream specification deviations

           buffer
               detect improper bitstream length

           explode
               abort decoding on minor error detection

       -mpeg_quant[:stream_specifier] integer (output,video)
           use MPEG quantizers instead of H.263

       -qsquish[:stream_specifier] float (output,video)
           how to keep quantizer between qmin and qmax (0 = clip, 1 = use
           differentiable function)

       -rc_qmod_amp[:stream_specifier] float (output,video)
           experimental quantizer modulation

       -rc_qmod_freq[:stream_specifier] integer (output,video)
           experimental quantizer modulation

       -rc_eq[:stream_specifier] string (output,video)
           Set rate control equation. When computing the expression, besides
           the standard functions defined in the section 'Expression
           Evaluation', the following functions are available: bits2qp(bits),
           qp2bits(qp). Also the following constants are available: iTex pTex
           tex mv fCode iCount mcVar var isI isP isB avgQP qComp avgIITex
           avgPITex avgPPTex avgBPTex avgTex.

       -maxrate[:stream_specifier] integer (output,audio,video)
           Set maximum bitrate tolerance (in bits/s). Requires bufsize to be
           set.

       -minrate[:stream_specifier] integer (output,audio,video)
           Set minimum bitrate tolerance (in bits/s). Most useful in setting
           up a CBR encode. It is of little use otherwise.

       -bufsize[:stream_specifier] integer (output,audio,video)
           set ratecontrol buffer size (in bits)

       -rc_buf_aggressivity[:stream_specifier] float (output,video)
           currently useless

       -i_qfactor[:stream_specifier] float (output,video)
           QP factor between P- and I-frames

       -i_qoffset[:stream_specifier] float (output,video)
           QP offset between P- and I-frames

       -rc_init_cplx[:stream_specifier] float (output,video)
           initial complexity for 1-pass encoding

       -dct[:stream_specifier] integer (output,video)
           DCT algorithm

           Possible values:

           auto
               autoselect a good one (default)

           fastint
               fast integer

           int accurate integer

           mmx
           altivec
           faan
               floating point AAN DCT

       -lumi_mask[:stream_specifier] float (output,video)
           compresses bright areas stronger than medium ones

       -tcplx_mask[:stream_specifier] float (output,video)
           temporal complexity masking

       -scplx_mask[:stream_specifier] float (output,video)
           spatial complexity masking

       -p_mask[:stream_specifier] float (output,video)
           inter masking

       -dark_mask[:stream_specifier] float (output,video)
           compresses dark areas stronger than medium ones

       -idct[:stream_specifier] integer (input/output,video)
           select IDCT implementation

           Possible values:

           auto
           int
           simple
           simplemmx
           arm
           altivec
           sh4
           simplearm
           simplearmv5te
           simplearmv6
           simpleneon
           simplealpha
           ipp
           xvid
           xvidmmx
           faani
               floating point AAN IDCT

       -ec[:stream_specifier] flags (input,video)
           set error concealment strategy

           Possible values:

           guess_mvs
               iterative motion vector (MV) search (slow)

           deblock
               use strong deblock filter for damaged MBs

       -pred[:stream_specifier] integer (output,video)
           prediction method

           Possible values:

           left
           plane
           median
       -aspect[:stream_specifier] rational number (output,video)
           sample aspect ratio

       -debug[:stream_specifier] flags (input/output,audio,video,subtitles)
           print specific debug info

           Possible values:

           pict
               picture info

           rc  rate control

           bitstream
           mb_type
               macroblock (MB) type

           qp  per-block quantization parameter (QP)

           mv  motion vector

           dct_coeff
           skip
           startcode
           pts
           er  error recognition

           mmco
               memory management control operations (H.264)

           bugs
           vis_qp
               visualize quantization parameter (QP), lower QP are tinted
               greener

           vis_mb_type
               visualize block types

           buffers
               picture buffer allocations

           thread_ops
               threading operations

       -vismv[:stream_specifier] integer (input,video)
           visualize motion vectors (MVs)

           Possible values:

           pf  forward predicted MVs of P-frames

           bf  forward predicted MVs of B-frames

           bb  backward predicted MVs of B-frames

       -cmp[:stream_specifier] integer (output,video)
           full-pel ME compare function

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           dctmax
           chroma
       -subcmp[:stream_specifier] integer (output,video)
           sub-pel ME compare function

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           dctmax
           chroma
       -mbcmp[:stream_specifier] integer (output,video)
           macroblock compare function

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           dctmax
           chroma
       -ildctcmp[:stream_specifier] integer (output,video)
           interlaced DCT compare function

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           dctmax
           chroma
       -dia_size[:stream_specifier] integer (output,video)
           diamond type & size for motion estimation

       -last_pred[:stream_specifier] integer (output,video)
           amount of motion predictors from the previous frame

       -preme[:stream_specifier] integer (output,video)
           pre motion estimation

       -precmp[:stream_specifier] integer (output,video)
           pre motion estimation compare function

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           dctmax
           chroma
       -pre_dia_size[:stream_specifier] integer (output,video)
           diamond type & size for motion estimation pre-pass

       -subq[:stream_specifier] integer (output,video)
           sub-pel motion estimation quality

       -me_range[:stream_specifier] integer (output,video)
           limit motion vectors range (1023 for DivX player)

       -ibias[:stream_specifier] integer (output,video)
           intra quant bias

       -pbias[:stream_specifier] integer (output,video)
           inter quant bias

       -global_quality[:stream_specifier] integer (output,audio,video)
       -coder[:stream_specifier] integer (output,video)
           Possible values:

           vlc variable length coder / Huffman coder

           ac  arithmetic coder

           raw raw (no encoding)

           rle run-length coder

           deflate
               deflate-based coder

       -context[:stream_specifier] integer (output,video)
           context model

       -mbd[:stream_specifier] integer (output,video)
           macroblock decision algorithm (high quality mode)

           Possible values:

           simple
               use mbcmp (default)

           bits
               use fewest bits

           rd  use best rate distortion

       -sc_threshold[:stream_specifier] integer (output,video)
           scene change threshold

       -lmin[:stream_specifier] integer (output,video)
           minimum Lagrange factor (VBR)

       -lmax[:stream_specifier] integer (output,video)
           maximum Lagrange factor (VBR)

       -nr[:stream_specifier] integer (output,video)
           noise reduction

       -rc_init_occupancy[:stream_specifier] integer (output,video)
           number of bits which should be loaded into the rc buffer before
           decoding starts

       -flags2[:stream_specifier] flags (input/output,audio,video)
           Possible values:

           fast
               allow non-spec-compliant speedup tricks

           noout
               skip bitstream encoding

           ignorecrop
               ignore cropping information from sps

           local_header
               place global headers at every keyframe instead of in extradata

       -error[:stream_specifier] integer (output,video)
       -threads[:stream_specifier] integer (input/output,video)
           Possible values:

           auto
               autodetect a suitable number of threads to use

       -me_threshold[:stream_specifier] integer (output,video)
           motion estimation threshold

       -mb_threshold[:stream_specifier] integer (output,video)
           macroblock threshold

       -dc[:stream_specifier] integer (output,video)
           intra_dc_precision

       -nssew[:stream_specifier] integer (output,video)
           nsse weight

       -skip_top[:stream_specifier] integer (input,video)
           number of macroblock rows at the top which are skipped

       -skip_bottom[:stream_specifier] integer (input,video)
           number of macroblock rows at the bottom which are skipped

       -profile[:stream_specifier] integer (output,audio,video)
           Possible values:

           unknown
           aac_main
           aac_low
           aac_ssr
           aac_ltp
           aac_he
           aac_he_v2
           aac_ld
           aac_eld
           mpeg2_aac_low
           mpeg2_aac_he
           dts
           dts_es
           dts_96_24
           dts_hd_hra
           dts_hd_ma
       -level[:stream_specifier] integer (output,audio,video)
           Possible values:

           unknown
       -skip_threshold[:stream_specifier] integer (output,video)
           frame skip threshold

       -skip_factor[:stream_specifier] integer (output,video)
           frame skip factor

       -skip_exp[:stream_specifier] integer (output,video)
           frame skip exponent

       -skipcmp[:stream_specifier] integer (output,video)
           frame skip compare function

           Possible values:

           sad sum of absolute differences, fast (default)

           sse sum of squared errors

           satd
               sum of absolute Hadamard transformed differences

           dct sum of absolute DCT transformed differences

           psnr
               sum of squared quantization errors (avoid, low quality)

           bit number of bits needed for the block

           rd  rate distortion optimal, slow

           zero
               0

           vsad
               sum of absolute vertical differences

           vsse
               sum of squared vertical differences

           nsse
               noise preserving sum of squared differences

           dctmax
           chroma
       -border_mask[:stream_specifier] float (output,video)
           increase the quantizer for macroblocks close to borders

       -mblmin[:stream_specifier] integer (output,video)
           minimum macroblock Lagrange factor (VBR)

       -mblmax[:stream_specifier] integer (output,video)
           maximum macroblock Lagrange factor (VBR)

       -mepc[:stream_specifier] integer (output,video)
           motion estimation bitrate penalty compensation (1.0 = 256)

       -skip_loop_filter[:stream_specifier] integer (input,video)
           Possible values:

           none
           default
           noref
           bidir
           nokey
           all
       -skip_idct[:stream_specifier] integer (input,video)
           Possible values:

           none
           default
           noref
           bidir
           nokey
           all
       -skip_frame[:stream_specifier] integer (input,video)
           Possible values:

           none
           default
           noref
           bidir
           nokey
           all
       -bidir_refine[:stream_specifier] integer (output,video)
           refine the two motion vectors used in bidirectional macroblocks

       -brd_scale[:stream_specifier] integer (output,video)
           downscale frames for dynamic B-frame decision

       -keyint_min[:stream_specifier] integer (output,video)
           minimum interval between IDR-frames (x264)

       -refs[:stream_specifier] integer (output,video)
           reference frames to consider for motion compensation

       -chromaoffset[:stream_specifier] integer (output,video)
           chroma QP offset from luma

       -trellis[:stream_specifier] integer (output,audio,video)
           rate-distortion optimal quantization

       -sc_factor[:stream_specifier] integer (output,video)
           multiplied by qscale for each frame and added to scene_change_score

       -mv0_threshold[:stream_specifier] integer (output,video)
       -b_sensitivity[:stream_specifier] integer (output,video)
           adjust sensitivity of b_frame_strategy 1

       -compression_level[:stream_specifier] integer (output,audio,video)
       -min_prediction_order[:stream_specifier] integer (output,audio)
       -max_prediction_order[:stream_specifier] integer (output,audio)
       -timecode_frame_start[:stream_specifier] integer (output,video)
           GOP timecode frame start number, in non-drop-frame format

       -request_channels[:stream_specifier] integer (input,audio)
           set desired number of audio channels

       -channel_layout[:stream_specifier] integer (input/output,audio)
           Possible values:

       -request_channel_layout[:stream_specifier] integer (input,audio)
           Possible values:

       -rc_max_vbv_use[:stream_specifier] float (output,video)
       -rc_min_vbv_use[:stream_specifier] float (output,video)
       -ticks_per_frame[:stream_specifier] integer (input/output,audio,video)
       -color_primaries[:stream_specifier] integer (input/output,video)
           color primaries

           Possible values:

           bt709
               BT.709

           unspecified
               Unspecified

           bt470m
               BT.470 M

           bt470bg
               BT.470 BG

           smpte170m
               SMPTE 170 M

           smpte240m
               SMPTE 240 M

           film
               Film

           bt2020
               BT.2020

       -color_trc[:stream_specifier] integer (input/output,video)
           color transfert characteristic

           Possible values:

           bt709
               BT.709

           unspecified
               Unspecified

           gamma22
               Gamma 2.2

           gamma28
               Gamma 2.8

           smpte170m
               SMPTE 170 M

           smpte240m
               SMPTE 240 M

           linear
               Linear

           log SMPTE 240 M

           log_sqrt
               SMPTE 240 M

           iec61966_2_4
               SMPTE 240 M

           bt1361
               BT.1361

           iec61966_2_1
               SMPTE 240 M

           bt2020_10bit
               BT.2020 - 10 bit

           bt2020_12bit
               BT.2020 - 12 bit

       -colorspace[:stream_specifier] integer (input/output,video)
           colorspace

           Possible values:

           rgb RGB

           bt709
               BT.709

           unspecified
               Unspecified

           fcc FourCC

           bt470bg
               BT.470 BG

           smpte170m
               SMPTE 170 M

           smpte240m
               SMPTE 240 M

           ycocg
               YCOCG

           bt2020_ncl
               BT.2020 NCL

           bt2020_cl
               BT.2020 CL

       -color_range[:stream_specifier] integer (input/output,video)
           color range

           Possible values:

           unspecified
               Unspecified

           mpeg
               MPEG (219*2^(n-8))

           jpeg
               JPEG (2^n-1)

       -chroma_sample_location[:stream_specifier] integer (input/output,video)
       -slices[:stream_specifier] integer (output,video)
           number of slices, used in parallelized encoding

       -thread_type[:stream_specifier] flags (input/output,video)
           select multithreading type

           Possible values:

           slice
           frame
       -audio_service_type[:stream_specifier] integer (output,audio)
           audio service type

           Possible values:

           ma  Main Audio Service

           ef  Effects

           vi  Visually Impaired

           hi  Hearing Impaired

           di  Dialogue

           co  Commentary

           em  Emergency

           vo  Voice Over

           ka  Karaoke

       -request_sample_fmt[:stream_specifier] integer (input,audio)
           Possible values:

           u8  8-bit unsigned integer

           s16 16-bit signed integer

           s32 32-bit signed integer

           flt 32-bit float

           dbl 64-bit double

           u8p 8-bit unsigned integer planar

           s16p
               16-bit signed integer planar

           s32p
               32-bit signed integer planar

           fltp
               32-bit float planar

           dblp
               64-bit double planar

       -refcounted_frames[:stream_specifier] integer (input,audio,video)
       -side_data_only_packets[:stream_specifier] integer (output,audio,video)

   Format AVOptions
       -probesize integer (input)
           set probing size

       -packetsize integer (output)
           set packet size

       -fflags flags (input/output)
           Possible values:

           flush_packets
               reduce the latency by flushing out packets immediately

           ignidx
               ignore index

           genpts
               generate pts

           nofillin
               do not fill in missing values that can be exactly calculated

           noparse
               disable AVParsers, this needs nofillin too

           igndts
               ignore dts

           discardcorrupt
               discard corrupted frames

           nobuffer
               reduce the latency introduced by optional buffering

           bitexact
               do not write random/volatile data

       -analyzeduration integer (input)
           how many microseconds are analyzed to estimate duration

       -cryptokey hexadecimal string (input)
           decryption key

       -indexmem integer (input)
           max memory used for timestamp index (per stream)

       -rtbufsize integer (input)
           max memory used for buffering real-time frames

       -fdebug flags (input/output)
           print specific debug info

           Possible values:

           ts
       -max_delay integer (input/output)
           maximum muxing or demuxing delay in microseconds

       -fpsprobesize integer (input)
           number of frames used to probe fps

       -f_err_detect flags (input)
           set error detection flags (deprecated; use err_detect, save via
           avconv)

           Possible values:

           crccheck
               verify embedded CRCs

           bitstream
               detect bitstream specification deviations

           buffer
               detect improper bitstream length

           explode
               abort decoding on minor error detection

       -err_detect flags (input)
           set error detection flags

           Possible values:

           crccheck
               verify embedded CRCs

           bitstream
               detect bitstream specification deviations

           buffer
               detect improper bitstream length

           explode
               abort decoding on minor error detection

       -max_interleave_delta integer (output)
           maximum buffering duration for interleaving

       -f_strict integer (input/output)
           how strictly to follow the standards (deprecated; use strict, save
           via avconv)

           Possible values:

           strict
               strictly conform to all the things in the spec no matter what
               the consequences

           normal
           experimental
               allow non-standardized experimental variants

       -strict integer (input/output)
           how strictly to follow the standards

           Possible values:

           strict
               strictly conform to all the things in the spec no matter what
               the consequences

           normal
           experimental
               allow non-standardized experimental variants

   Main options
       -f format
           Force format to use.

       -of formatter
           Use a specific formatter to output the document. The following
           formatters are available

           ini
           json
           old Pseudo-INI format that used to be the only one available in old
               avprobe versions.

       -unit
           Show the unit of the displayed values.

       -prefix
           Use SI prefixes for the displayed values.  Unless the
           "-byte_binary_prefix" option is used all the prefixes are decimal.

       -byte_binary_prefix
           Force the use of binary prefixes for byte values.

       -sexagesimal
           Use sexagesimal format HH:MM:SS.MICROSECONDS for time values.

       -pretty
           Prettify the format of the displayed values, it corresponds to the
           options "-unit -prefix -byte_binary_prefix -sexagesimal".

       -show_format
           Show information about the container format of the input multimedia
           stream.

           All the container format information is printed within a section
           with name "FORMAT".

       -show_format_entry name
           Like -show_format, but only prints the specified entry of the
           container format information, rather than all. This option may be
           given more than once, then all specified entries will be shown.

       -show_packets
           Show information about each packet contained in the input
           multimedia stream.

           The information for each single packet is printed within a
           dedicated section with name "PACKET".

       -show_streams
           Show information about each media stream contained in the input
           multimedia stream.

           Each media stream information is printed within a dedicated section
           with name "STREAM".

       Demuxers are configured elements in Libav which allow to read the
       multimedia streams from a particular type of file.

       When you configure your Libav build, all the supported demuxers are
       enabled by default. You can list all available ones using the configure
       option "--list-demuxers".

       You can disable all the demuxers using the configure option
       "--disable-demuxers", and selectively enable a single demuxer with the
       option "--enable-demuxer=DEMUXER", or disable it with the option
       "--disable-demuxer=DEMUXER".

       The option "-formats" of the av* tools will display the list of enabled
       demuxers.

       The description of some of the currently available demuxers follows.

   image2
       Image file demuxer.

       This demuxer reads from a list of image files specified by a pattern.

       The pattern may contain the string "%d" or "%0Nd", which specifies the
       position of the characters representing a sequential number in each
       filename matched by the pattern. If the form "%d0Nd" is used, the
       string representing the number in each filename is 0-padded and N is
       the total number of 0-padded digits representing the number. The
       literal character '%' can be specified in the pattern with the string
       "%%".

       If the pattern contains "%d" or "%0Nd", the first filename of the file
       list specified by the pattern must contain a number inclusively
       contained between 0 and 4, all the following numbers must be
       sequential. This limitation may be hopefully fixed.

       The pattern may contain a suffix which is used to automatically
       determine the format of the images contained in the files.

       For example the pattern "img-%03d.bmp" will match a sequence of
       filenames of the form img-001.bmp, img-002.bmp, ..., img-010.bmp, etc.;
       the pattern "i%%m%%g-%d.jpg" will match a sequence of filenames of the
       form i%m%g-1.jpg, i%m%g-2.jpg, ..., i%m%g-10.jpg, etc.

       The size, the pixel format, and the format of each image must be the
       same for all the files in the sequence.

       The following example shows how to use avconv for creating a video from
       the images in the file sequence img-001.jpeg, img-002.jpeg, ...,
       assuming an input framerate of 10 frames per second:

               avconv -i 'img-%03d.jpeg' -r 10 out.mkv

       Note that the pattern must not necessarily contain "%d" or "%0Nd", for
       example to convert a single image file img.jpeg you can employ the
       command:

               avconv -i img.jpeg img.png

       -pixel_format format
           Set the pixel format (for raw image)

       -video_size   size
           Set the frame size (for raw image)

       -framerate    rate
           Set the frame rate

       -loop         bool
           Loop over the images

       -start_number start
           Specify the first number in the sequence

   applehttp
       Apple HTTP Live Streaming demuxer.

       This demuxer presents all AVStreams from all variant streams.  The id
       field is set to the bitrate variant index number. By setting the
       discard flags on AVStreams (by pressing 'a' or 'v' in avplay), the
       caller can decide which variant streams to actually receive.  The total
       bitrate of the variant that the stream belongs to is available in a
       metadata key named "variant_bitrate".

   flv
       Adobe Flash Video Format demuxer.

       This demuxer is used to demux FLV files and RTMP network streams.

       -flv_metadata bool
           Allocate the streams according to the onMetaData array content.

   asf
       Advanced Systems Format demuxer.

       This demuxer is used to demux ASF files and MMS network streams.

       -no_resync_search bool
           Do not try to resynchronize by looking for a certain optional start
           code.

       Muxers are configured elements in Libav which allow writing multimedia
       streams to a particular type of file.

       When you configure your Libav build, all the supported muxers are
       enabled by default. You can list all available muxers using the
       configure option "--list-muxers".

       You can disable all the muxers with the configure option
       "--disable-muxers" and selectively enable / disable single muxers with
       the options "--enable-muxer=MUXER" / "--disable-muxer=MUXER".

       The option "-formats" of the av* tools will display the list of enabled
       muxers.

       A description of some of the currently available muxers follows.

   crc
       CRC (Cyclic Redundancy Check) testing format.

       This muxer computes and prints the Adler-32 CRC of all the input audio
       and video frames. By default audio frames are converted to signed
       16-bit raw audio and video frames to raw video before computing the
       CRC.

       The output of the muxer consists of a single line of the form:
       CRC=0xCRC, where CRC is a hexadecimal number 0-padded to 8 digits
       containing the CRC for all the decoded input frames.

       For example to compute the CRC of the input, and store it in the file
       out.crc:

               avconv -i INPUT -f crc out.crc

       You can print the CRC to stdout with the command:

               avconv -i INPUT -f crc -

       You can select the output format of each frame with avconv by
       specifying the audio and video codec and format. For example to compute
       the CRC of the input audio converted to PCM unsigned 8-bit and the
       input video converted to MPEG-2 video, use the command:

               avconv -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -

       See also the framecrc muxer.

   framecrc
       Per-frame CRC (Cyclic Redundancy Check) testing format.

       This muxer computes and prints the Adler-32 CRC for each decoded audio
       and video frame. By default audio frames are converted to signed 16-bit
       raw audio and video frames to raw video before computing the CRC.

       The output of the muxer consists of a line for each audio and video
       frame of the form: stream_index, frame_dts, frame_size, 0xCRC, where
       CRC is a hexadecimal number 0-padded to 8 digits containing the CRC of
       the decoded frame.

       For example to compute the CRC of each decoded frame in the input, and
       store it in the file out.crc:

               avconv -i INPUT -f framecrc out.crc

       You can print the CRC of each decoded frame to stdout with the command:

               avconv -i INPUT -f framecrc -

       You can select the output format of each frame with avconv by
       specifying the audio and video codec and format. For example, to
       compute the CRC of each decoded input audio frame converted to PCM
       unsigned 8-bit and of each decoded input video frame converted to
       MPEG-2 video, use the command:

               avconv -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -

       See also the crc muxer.

   hls
       Apple HTTP Live Streaming muxer that segments MPEG-TS according to the
       HTTP Live Streaming specification.

       It creates a playlist file and numbered segment files. The output
       filename specifies the playlist filename; the segment filenames receive
       the same basename as the playlist, a sequential number and a .ts
       extension.

               avconv -i in.nut out.m3u8

       -hls_time seconds
           Set the segment length in seconds.

       -hls_list_size size
           Set the maximum number of playlist entries.

       -hls_wrap wrap
           Set the number after which index wraps.

       -start_number number
           Start the sequence from number.

       -hls_base_url baseurl
           Append baseurl to every entry in the playlist.  Useful to generate
           playlists with absolute paths.

   image2
       Image file muxer.

       The image file muxer writes video frames to image files.

       The output filenames are specified by a pattern, which can be used to
       produce sequentially numbered series of files.  The pattern may contain
       the string "%d" or "%0Nd", this string specifies the position of the
       characters representing a numbering in the filenames. If the form
       "%0Nd" is used, the string representing the number in each filename is
       0-padded to N digits. The literal character '%' can be specified in the
       pattern with the string "%%".

       If the pattern contains "%d" or "%0Nd", the first filename of the file
       list specified will contain the number 1, all the following numbers
       will be sequential.

       The pattern may contain a suffix which is used to automatically
       determine the format of the image files to write.

       For example the pattern "img-%03d.bmp" will specify a sequence of
       filenames of the form img-001.bmp, img-002.bmp, ..., img-010.bmp, etc.
       The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
       form img%-1.jpg, img%-2.jpg, ..., img%-10.jpg, etc.

       The following example shows how to use avconv for creating a sequence
       of files img-001.jpeg, img-002.jpeg, ..., taking one image every second
       from the input video:

               avconv -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'

       Note that with avconv, if the format is not specified with the "-f"
       option and the output filename specifies an image file format, the
       image2 muxer is automatically selected, so the previous command can be
       written as:

               avconv -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'

       Note also that the pattern must not necessarily contain "%d" or "%0Nd",
       for example to create a single image file img.jpeg from the input video
       you can employ the command:

               avconv -i in.avi -f image2 -frames:v 1 img.jpeg

       -start_number number
           Start the sequence from number.

       -update number
           If number is nonzero, the filename will always be interpreted as
           just a filename, not a pattern, and this file will be continuously
           overwritten with new images.

   matroska
       Matroska container muxer.

       This muxer implements the matroska and webm container specs.

       The recognized metadata settings in this muxer are:

       title=title name
           Name provided to a single track

       language=language name
           Specifies the language of the track in the Matroska languages form

       STEREO_MODE=mode
           Stereo 3D video layout of two views in a single video track

           mono
               video is not stereo

           left_right
               Both views are arranged side by side, Left-eye view is on the
               left

           bottom_top
               Both views are arranged in top-bottom orientation, Left-eye
               view is at bottom

           top_bottom
               Both views are arranged in top-bottom orientation, Left-eye
               view is on top

           checkerboard_rl
               Each view is arranged in a checkerboard interleaved pattern,
               Left-eye view being first

           checkerboard_lr
               Each view is arranged in a checkerboard interleaved pattern,
               Right-eye view being first

           row_interleaved_rl
               Each view is constituted by a row based interleaving, Right-eye
               view is first row

           row_interleaved_lr
               Each view is constituted by a row based interleaving, Left-eye
               view is first row

           col_interleaved_rl
               Both views are arranged in a column based interleaving manner,
               Right-eye view is first column

           col_interleaved_lr
               Both views are arranged in a column based interleaving manner,
               Left-eye view is first column

           anaglyph_cyan_red
               All frames are in anaglyph format viewable through red-cyan
               filters

           right_left
               Both views are arranged side by side, Right-eye view is on the
               left

           anaglyph_green_magenta
               All frames are in anaglyph format viewable through green-
               magenta filters

           block_lr
               Both eyes laced in one Block, Left-eye view is first

           block_rl
               Both eyes laced in one Block, Right-eye view is first

       For example a 3D WebM clip can be created using the following command
       line:

               avconv -i sample_left_right_clip.mpg -an -c:v libvpx -metadata STEREO_MODE=left_right -y stereo_clip.webm

       This muxer supports the following options:

       reserve_index_space
           By default, this muxer writes the index for seeking (called cues in
           Matroska terms) at the end of the file, because it cannot know in
           advance how much space to leave for the index at the beginning of
           the file. However for some use cases -- e.g.  streaming where
           seeking is possible but slow -- it is useful to put the index at
           the beginning of the file.

           If this option is set to a non-zero value, the muxer will reserve a
           given amount of space in the file header and then try to write the
           cues there when the muxing finishes. If the available space does
           not suffice, muxing will fail. A safe size for most use cases
           should be about 50kB per hour of video.

           Note that cues are only written if the output is seekable and this
           option will have no effect if it is not.

   mov, mp4, ismv
       The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4 file
       has all the metadata about all packets stored in one location (written
       at the end of the file, it can be moved to the start for better
       playback using the qt-faststart tool). A fragmented file consists of a
       number of fragments, where packets and metadata about these packets are
       stored together. Writing a fragmented file has the advantage that the
       file is decodable even if the writing is interrupted (while a normal
       MOV/MP4 is undecodable if it is not properly finished), and it requires
       less memory when writing very long files (since writing normal MOV/MP4
       files stores info about every single packet in memory until the file is
       closed). The downside is that it is less compatible with other
       applications.

       Fragmentation is enabled by setting one of the AVOptions that define
       how to cut the file into fragments:

       -movflags frag_keyframe
           Start a new fragment at each video keyframe.

       -frag_duration duration
           Create fragments that are duration microseconds long.

       -frag_size size
           Create fragments that contain up to size bytes of payload data.

       -movflags frag_custom
           Allow the caller to manually choose when to cut fragments, by
           calling "av_write_frame(ctx, NULL)" to write a fragment with the
           packets written so far. (This is only useful with other
           applications integrating libavformat, not from avconv.)

       -min_frag_duration duration
           Don't create fragments that are shorter than duration microseconds
           long.

       If more than one condition is specified, fragments are cut when one of
       the specified conditions is fulfilled. The exception to this is
       "-min_frag_duration", which has to be fulfilled for any of the other
       conditions to apply.

       Additionally, the way the output file is written can be adjusted
       through a few other options:

       -movflags empty_moov
           Write an initial moov atom directly at the start of the file,
           without describing any samples in it. Generally, an mdat/moov pair
           is written at the start of the file, as a normal MOV/MP4 file,
           containing only a short portion of the file. With this option set,
           there is no initial mdat atom, and the moov atom only describes the
           tracks but has a zero duration.

           Files written with this option set do not work in QuickTime.  This
           option is implicitly set when writing ismv (Smooth Streaming)
           files.

       -movflags separate_moof
           Write a separate moof (movie fragment) atom for each track.
           Normally, packets for all tracks are written in a moof atom (which
           is slightly more efficient), but with this option set, the muxer
           writes one moof/mdat pair for each track, making it easier to
           separate tracks.

           This option is implicitly set when writing ismv (Smooth Streaming)
           files.

       -movflags faststart
           Run a second pass moving the index (moov atom) to the beginning of
           the file.  This operation can take a while, and will not work in
           various situations such as fragmented output, thus it is not
           enabled by default.

       -movflags disable_chpl
           Disable Nero chapter markers (chpl atom).  Normally, both Nero
           chapters and a QuickTime chapter track are written to the file.
           With this option set, only the QuickTime chapter track will be
           written. Nero chapters can cause failures when the file is
           reprocessed with certain tagging programs.

       Smooth Streaming content can be pushed in real time to a publishing
       point on IIS with this muxer. Example:

               avconv -re <<normal input/transcoding options>> -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)

   mp3
       The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the
       beginning and optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4
       are supported, the "id3v2_version" option controls which one is used.
       Setting "id3v2_version" to 0 will disable the ID3v2 header completely.
       The legacy ID3v1 tag is not written by default, but may be enabled with
       the "write_id3v1" option.

       The muxer may also write a Xing frame at the beginning, which contains
       the number of frames in the file. It is useful for computing duration
       of VBR files.  The Xing frame is written if the output stream is
       seekable and if the "write_xing" option is set to 1 (the default).

       The muxer supports writing ID3v2 attached pictures (APIC frames). The
       pictures are supplied to the muxer in form of a video stream with a
       single packet. There can be any number of those streams, each will
       correspond to a single APIC frame.  The stream metadata tags title and
       comment map to APIC description and picture type respectively. See
       <http://id3.org/id3v2.4.0-frames> for allowed picture types.

       Note that the APIC frames must be written at the beginning, so the
       muxer will buffer the audio frames until it gets all the pictures. It
       is therefore advised to provide the pictures as soon as possible to
       avoid excessive buffering.

       Examples:

       Write an mp3 with an ID3v2.3 header and an ID3v1 footer:

               avconv -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3

       Attach a picture to an mp3:

               avconv -i input.mp3 -i cover.png -c copy -metadata:s:v title="Album cover"
               -metadata:s:v comment="Cover (Front)" out.mp3

       Write a "clean" MP3 without any extra features:

               avconv -i input.wav -write_xing 0 -id3v2_version 0 out.mp3

   mpegts
       MPEG transport stream muxer.

       This muxer implements ISO 13818-1 and part of ETSI EN 300 468.

       The muxer options are:

       -mpegts_original_network_id number
           Set the original_network_id (default 0x0001). This is unique
           identifier of a network in DVB. Its main use is in the unique
           identification of a service through the path Original_Network_ID,
           Transport_Stream_ID.

       -mpegts_transport_stream_id number
           Set the transport_stream_id (default 0x0001). This identifies a
           transponder in DVB.

       -mpegts_service_id number
           Set the service_id (default 0x0001) also known as program in DVB.

       -mpegts_pmt_start_pid number
           Set the first PID for PMT (default 0x1000, max 0x1f00).

       -mpegts_start_pid number
           Set the first PID for data packets (default 0x0100, max 0x0f00).

       -muxrate number
           Set a constant muxrate (default VBR).

       -pcr_period numer
           Override the default PCR retransmission time (default 20ms),
           ignored if variable muxrate is selected.

       The recognized metadata settings in mpegts muxer are "service_provider"
       and "service_name". If they are not set the default for
       "service_provider" is "Libav" and the default for "service_name" is
       "Service01".

               avconv -i file.mpg -c copy \
                    -mpegts_original_network_id 0x1122 \
                    -mpegts_transport_stream_id 0x3344 \
                    -mpegts_service_id 0x5566 \
                    -mpegts_pmt_start_pid 0x1500 \
                    -mpegts_start_pid 0x150 \
                    -metadata service_provider="Some provider" \
                    -metadata service_name="Some Channel" \
                    -y out.ts

   null
       Null muxer.

       This muxer does not generate any output file, it is mainly useful for
       testing or benchmarking purposes.

       For example to benchmark decoding with avconv you can use the command:

               avconv -benchmark -i INPUT -f null out.null

       Note that the above command does not read or write the out.null file,
       but specifying the output file is required by the avconv syntax.

       Alternatively you can write the command as:

               avconv -benchmark -i INPUT -f null -

   nut
       -syncpoints flags
           Change the syncpoint usage in nut:

           default use the normal low-overhead seeking aids.
           none do not use the syncpoints at all, reducing the overhead but
           making the stream non-seekable;
           timestamped extend the syncpoint with a wallclock field.

           The none and timestamped flags are experimental.

               avconv -i INPUT -f_strict experimental -syncpoints none - | processor

   ogg
       Ogg container muxer.

       -page_duration duration
           Preferred page duration, in microseconds. The muxer will attempt to
           create pages that are approximately duration microseconds long.
           This allows the user to compromise between seek granularity and
           container overhead. The default is 1 second. A value of 0 will fill
           all segments, making pages as large as possible. A value of 1 will
           effectively use 1 packet-per-page in most situations, giving a
           small seek granularity at the cost of additional container
           overhead.

   segment
       Basic stream segmenter.

       The segmenter muxer outputs streams to a number of separate files of
       nearly fixed duration. Output filename pattern can be set in a fashion
       similar to image2.

       Every segment starts with a video keyframe, if a video stream is
       present.  The segment muxer works best with a single constant frame
       rate video.

       Optionally it can generate a flat list of the created segments, one
       segment per line.

       segment_format format
           Override the inner container format, by default it is guessed by
           the filename extension.

       segment_time t
           Set segment duration to t seconds.

       segment_list name
           Generate also a listfile named name.

       segment_list_type type
           Select the listing format.

           flat use a simple flat list of entries.
           hls use a m3u8-like structure.
       segment_list_size size
           Overwrite the listfile once it reaches size entries.

       segment_list_entry_prefix prefix
           Prepend prefix to each entry. Useful to generate absolute paths.

       segment_wrap limit
           Wrap around segment index once it reaches limit.

               avconv -i in.mkv -c copy -map 0 -f segment -list out.list out%03d.nut

       Protocols are configured elements in Libav which allow to access
       resources which require the use of a particular protocol.

       When you configure your Libav build, all the supported protocols are
       enabled by default. You can list all available ones using the configure
       option "--list-protocols".

       You can disable all the protocols using the configure option
       "--disable-protocols", and selectively enable a protocol using the
       option "--enable-protocol=PROTOCOL", or you can disable a particular
       protocol using the option "--disable-protocol=PROTOCOL".

       The option "-protocols" of the av* tools will display the list of
       supported protocols.

       A description of the currently available protocols follows.

   concat
       Physical concatenation protocol.

       Allow to read and seek from many resource in sequence as if they were a
       unique resource.

       A URL accepted by this protocol has the syntax:

               concat:<URL1>|<URL2>|...|<URLN>

       where URL1, URL2, ..., URLN are the urls of the resource to be
       concatenated, each one possibly specifying a distinct protocol.

       For example to read a sequence of files split1.mpeg, split2.mpeg,
       split3.mpeg with avplay use the command:

               avplay concat:split1.mpeg\|split2.mpeg\|split3.mpeg

       Note that you may need to escape the character "|" which is special for
       many shells.

   file
       File access protocol.

       Allow to read from or read to a file.

       For example to read from a file input.mpeg with avconv use the command:

               avconv -i file:input.mpeg output.mpeg

       The av* tools default to the file protocol, that is a resource
       specified with the name "FILE.mpeg" is interpreted as the URL
       "file:FILE.mpeg".

   gopher
       Gopher protocol.

   hls
       Read Apple HTTP Live Streaming compliant segmented stream as a uniform
       one. The M3U8 playlists describing the segments can be remote HTTP
       resources or local files, accessed using the standard file protocol.
       The nested protocol is declared by specifying "+proto" after the hls
       URI scheme name, where proto is either "file" or "http".

               hls+http://host/path/to/remote/resource.m3u8
               hls+file://path/to/local/resource.m3u8

       Using this protocol is discouraged - the hls demuxer should work just
       as well (if not, please report the issues) and is more complete.  To
       use the hls demuxer instead, simply use the direct URLs to the m3u8
       files.

   http
       HTTP (Hyper Text Transfer Protocol).

       This protocol accepts the following options:

       chunked_post
           If set to 1 use chunked Transfer-Encoding for posts, default is 1.

       content_type
           Set a specific content type for the POST messages.

       headers
           Set custom HTTP headers, can override built in default headers. The
           value must be a string encoding the headers.

       multiple_requests
           Use persistent connections if set to 1, default is 0.

       post_data
           Set custom HTTP post data.

       user_agent
           Override the User-Agent header. If not specified a string of the
           form "Lavf/<version>" will be used.

       mime_type
           Export the MIME type.

       icy If set to 1 request ICY (SHOUTcast) metadata from the server. If
           the server supports this, the metadata has to be retrieved by the
           application by reading the icy_metadata_headers and
           icy_metadata_packet options.  The default is 1.

       icy_metadata_headers
           If the server supports ICY metadata, this contains the ICY-specific
           HTTP reply headers, separated by newline characters.

       icy_metadata_packet
           If the server supports ICY metadata, and icy was set to 1, this
           contains the last non-empty metadata packet sent by the server. It
           should be polled in regular intervals by applications interested in
           mid-stream metadata updates.

       offset
           Set initial byte offset.

       end_offset
           Try to limit the request to bytes preceding this offset.

   Icecast
       Icecast (stream to Icecast servers)

       This protocol accepts the following options:

       ice_genre
           Set the stream genre.

       ice_name
           Set the stream name.

       ice_description
           Set the stream description.

       ice_url
           Set the stream website URL.

       ice_public
           Set if the stream should be public or not.  The default is 0 (not
           public).

       user_agent
           Override the User-Agent header. If not specified a string of the
           form "Lavf/<version>" will be used.

       password
           Set the Icecast mountpoint password.

       content_type
           Set the stream content type. This must be set if it is different
           from audio/mpeg.

       legacy_icecast
           This enables support for Icecast versions < 2.4.0, that do not
           support the HTTP PUT method but the SOURCE method.

   mmst
       MMS (Microsoft Media Server) protocol over TCP.

   mmsh
       MMS (Microsoft Media Server) protocol over HTTP.

       The required syntax is:

               mmsh://<server>[:<port>][/<app>][/<playpath>]

   md5
       MD5 output protocol.

       Computes the MD5 hash of the data to be written, and on close writes
       this to the designated output or stdout if none is specified. It can be
       used to test muxers without writing an actual file.

       Some examples follow.

               # Write the MD5 hash of the encoded AVI file to the file output.avi.md5.
               avconv -i input.flv -f avi -y md5:output.avi.md5

               # Write the MD5 hash of the encoded AVI file to stdout.
               avconv -i input.flv -f avi -y md5:

       Note that some formats (typically MOV) require the output protocol to
       be seekable, so they will fail with the MD5 output protocol.

   pipe
       UNIX pipe access protocol.

       Allow to read and write from UNIX pipes.

       The accepted syntax is:

               pipe:[<number>]

       number is the number corresponding to the file descriptor of the pipe
       (e.g. 0 for stdin, 1 for stdout, 2 for stderr).  If number is not
       specified, by default the stdout file descriptor will be used for
       writing, stdin for reading.

       For example to read from stdin with avconv:

               cat test.wav | avconv -i pipe:0
               # ...this is the same as...
               cat test.wav | avconv -i pipe:

       For writing to stdout with avconv:

               avconv -i test.wav -f avi pipe:1 | cat > test.avi
               # ...this is the same as...
               avconv -i test.wav -f avi pipe: | cat > test.avi

       Note that some formats (typically MOV), require the output protocol to
       be seekable, so they will fail with the pipe output protocol.

   rtmp
       Real-Time Messaging Protocol.

       The Real-Time Messaging Protocol (RTMP) is used for streaming
       multimedia content across a TCP/IP network.

       The required syntax is:

               rtmp://[<username>:<password>@]<server>[:<port>][/<app>][/<instance>][/<playpath>]

       The accepted parameters are:

       username
           An optional username (mostly for publishing).

       password
           An optional password (mostly for publishing).

       server
           The address of the RTMP server.

       port
           The number of the TCP port to use (by default is 1935).

       app It is the name of the application to access. It usually corresponds
           to the path where the application is installed on the RTMP server
           (e.g. /ondemand/, /flash/live/, etc.). You can override the value
           parsed from the URI through the "rtmp_app" option, too.

       playpath
           It is the path or name of the resource to play with reference to
           the application specified in app, may be prefixed by "mp4:". You
           can override the value parsed from the URI through the
           "rtmp_playpath" option, too.

       listen
           Act as a server, listening for an incoming connection.

       timeout
           Maximum time to wait for the incoming connection. Implies listen.

       Additionally, the following parameters can be set via command line
       options (or in code via "AVOption"s):

       rtmp_app
           Name of application to connect on the RTMP server. This option
           overrides the parameter specified in the URI.

       rtmp_buffer
           Set the client buffer time in milliseconds. The default is 3000.

       rtmp_conn
           Extra arbitrary AMF connection parameters, parsed from a string,
           e.g. like "B:1 S:authMe O:1 NN:code:1.23 NS:flag:ok O:0".  Each
           value is prefixed by a single character denoting the type, B for
           Boolean, N for number, S for string, O for object, or Z for null,
           followed by a colon. For Booleans the data must be either 0 or 1
           for FALSE or TRUE, respectively.  Likewise for Objects the data
           must be 0 or 1 to end or begin an object, respectively. Data items
           in subobjects may be named, by prefixing the type with 'N' and
           specifying the name before the value (i.e. "NB:myFlag:1"). This
           option may be used multiple times to construct arbitrary AMF
           sequences.

       rtmp_flashver
           Version of the Flash plugin used to run the SWF player. The default
           is LNX 9,0,124,2. (When publishing, the default is FMLE/3.0
           (compatible; <libavformat version>).)

       rtmp_flush_interval
           Number of packets flushed in the same request (RTMPT only). The
           default is 10.

       rtmp_live
           Specify that the media is a live stream. No resuming or seeking in
           live streams is possible. The default value is "any", which means
           the subscriber first tries to play the live stream specified in the
           playpath. If a live stream of that name is not found, it plays the
           recorded stream. The other possible values are "live" and
           "recorded".

       rtmp_pageurl
           URL of the web page in which the media was embedded. By default no
           value will be sent.

       rtmp_playpath
           Stream identifier to play or to publish. This option overrides the
           parameter specified in the URI.

       rtmp_subscribe
           Name of live stream to subscribe to. By default no value will be
           sent.  It is only sent if the option is specified or if rtmp_live
           is set to live.

       rtmp_swfhash
           SHA256 hash of the decompressed SWF file (32 bytes).

       rtmp_swfsize
           Size of the decompressed SWF file, required for SWFVerification.

       rtmp_swfurl
           URL of the SWF player for the media. By default no value will be
           sent.

       rtmp_swfverify
           URL to player swf file, compute hash/size automatically.

       rtmp_tcurl
           URL of the target stream. Defaults to proto://host[:port]/app.

       For example to read with avplay a multimedia resource named "sample"
       from the application "vod" from an RTMP server "myserver":

               avplay rtmp://myserver/vod/sample

       To publish to a password protected server, passing the playpath and app
       names separately:

               avconv -re -i <input> -f flv -rtmp_playpath some/long/path -rtmp_app long/app/name rtmp://username:password@myserver/

   rtmpe
       Encrypted Real-Time Messaging Protocol.

       The Encrypted Real-Time Messaging Protocol (RTMPE) is used for
       streaming multimedia content within standard cryptographic primitives,
       consisting of Diffie-Hellman key exchange and HMACSHA256, generating a
       pair of RC4 keys.

   rtmps
       Real-Time Messaging Protocol over a secure SSL connection.

       The Real-Time Messaging Protocol (RTMPS) is used for streaming
       multimedia content across an encrypted connection.

   rtmpt
       Real-Time Messaging Protocol tunneled through HTTP.

       The Real-Time Messaging Protocol tunneled through HTTP (RTMPT) is used
       for streaming multimedia content within HTTP requests to traverse
       firewalls.

   rtmpte
       Encrypted Real-Time Messaging Protocol tunneled through HTTP.

       The Encrypted Real-Time Messaging Protocol tunneled through HTTP
       (RTMPTE) is used for streaming multimedia content within HTTP requests
       to traverse firewalls.

   rtmpts
       Real-Time Messaging Protocol tunneled through HTTPS.

       The Real-Time Messaging Protocol tunneled through HTTPS (RTMPTS) is
       used for streaming multimedia content within HTTPS requests to traverse
       firewalls.

   librtmp rtmp, rtmpe, rtmps, rtmpt, rtmpte
       Real-Time Messaging Protocol and its variants supported through
       librtmp.

       Requires the presence of the librtmp headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-librtmp". If enabled this will replace the native RTMP
       protocol.

       This protocol provides most client functions and a few server functions
       needed to support RTMP, RTMP tunneled in HTTP (RTMPT), encrypted RTMP
       (RTMPE), RTMP over SSL/TLS (RTMPS) and tunneled variants of these
       encrypted types (RTMPTE, RTMPTS).

       The required syntax is:

               <rtmp_proto>://<server>[:<port>][/<app>][/<playpath>] <options>

       where rtmp_proto is one of the strings "rtmp", "rtmpt", "rtmpe",
       "rtmps", "rtmpte", "rtmpts" corresponding to each RTMP variant, and
       server, port, app and playpath have the same meaning as specified for
       the RTMP native protocol.  options contains a list of space-separated
       options of the form key=val.

       See the librtmp manual page (man 3 librtmp) for more information.

       For example, to stream a file in real-time to an RTMP server using
       avconv:

               avconv -re -i myfile -f flv rtmp://myserver/live/mystream

       To play the same stream using avplay:

               avplay "rtmp://myserver/live/mystream live=1"

   rtp
       Real-Time Protocol.

   rtsp
       RTSP is not technically a protocol handler in libavformat, it is a
       demuxer and muxer. The demuxer supports both normal RTSP (with data
       transferred over RTP; this is used by e.g. Apple and Microsoft) and
       Real-RTSP (with data transferred over RDT).

       The muxer can be used to send a stream using RTSP ANNOUNCE to a server
       supporting it (currently Darwin Streaming Server and Mischa
       Spiegelmock's
        RTSP server ("http://github.com/revmischa/rtsp-server")).

       The required syntax for a RTSP url is:

               rtsp://<hostname>[:<port>]/<path>

       The following options (set on the avconv/avplay command line, or set in
       code via "AVOption"s or in "avformat_open_input"), are supported:

       Flags for "rtsp_transport":

       udp Use UDP as lower transport protocol.

       tcp Use TCP (interleaving within the RTSP control channel) as lower
           transport protocol.

       udp_multicast
           Use UDP multicast as lower transport protocol.

       http
           Use HTTP tunneling as lower transport protocol, which is useful for
           passing proxies.

       Multiple lower transport protocols may be specified, in that case they
       are tried one at a time (if the setup of one fails, the next one is
       tried).  For the muxer, only the "tcp" and "udp" options are supported.

       Flags for "rtsp_flags":

       filter_src
           Accept packets only from negotiated peer address and port.

       listen
           Act as a server, listening for an incoming connection.

       When receiving data over UDP, the demuxer tries to reorder received
       packets (since they may arrive out of order, or packets may get lost
       totally). This can be disabled by setting the maximum demuxing delay to
       zero (via the "max_delay" field of AVFormatContext).

       When watching multi-bitrate Real-RTSP streams with avplay, the streams
       to display can be chosen with "-vst" n and "-ast" n for video and audio
       respectively, and can be switched on the fly by pressing "v" and "a".

       Example command lines:

       To watch a stream over UDP, with a max reordering delay of 0.5 seconds:

               avplay -max_delay 500000 -rtsp_transport udp rtsp://server/video.mp4

       To watch a stream tunneled over HTTP:

               avplay -rtsp_transport http rtsp://server/video.mp4

       To send a stream in realtime to a RTSP server, for others to watch:

               avconv -re -i <input> -f rtsp -muxdelay 0.1 rtsp://server/live.sdp

       To receive a stream in realtime:

               avconv -rtsp_flags listen -i rtsp://ownaddress/live.sdp <output>

   sap
       Session Announcement Protocol (RFC 2974). This is not technically a
       protocol handler in libavformat, it is a muxer and demuxer.  It is used
       for signalling of RTP streams, by announcing the SDP for the streams
       regularly on a separate port.

       Muxer

       The syntax for a SAP url given to the muxer is:

               sap://<destination>[:<port>][?<options>]

       The RTP packets are sent to destination on port port, or to port 5004
       if no port is specified.  options is a "&"-separated list. The
       following options are supported:

       announce_addr=address
           Specify the destination IP address for sending the announcements
           to.  If omitted, the announcements are sent to the commonly used
           SAP announcement multicast address 224.2.127.254 (sap.mcast.net),
           or ff0e::2:7ffe if destination is an IPv6 address.

       announce_port=port
           Specify the port to send the announcements on, defaults to 9875 if
           not specified.

       ttl=ttl
           Specify the time to live value for the announcements and RTP
           packets, defaults to 255.

       same_port=0|1
           If set to 1, send all RTP streams on the same port pair. If zero
           (the default), all streams are sent on unique ports, with each
           stream on a port 2 numbers higher than the previous.  VLC/Live555
           requires this to be set to 1, to be able to receive the stream.
           The RTP stack in libavformat for receiving requires all streams to
           be sent on unique ports.

       Example command lines follow.

       To broadcast a stream on the local subnet, for watching in VLC:

               avconv -re -i <input> -f sap sap://224.0.0.255?same_port=1

       Similarly, for watching in avplay:

               avconv -re -i <input> -f sap sap://224.0.0.255

       And for watching in avplay, over IPv6:

               avconv -re -i <input> -f sap sap://[ff0e::1:2:3:4]

       Demuxer

       The syntax for a SAP url given to the demuxer is:

               sap://[<address>][:<port>]

       address is the multicast address to listen for announcements on, if
       omitted, the default 224.2.127.254 (sap.mcast.net) is used. port is the
       port that is listened on, 9875 if omitted.

       The demuxers listens for announcements on the given address and port.
       Once an announcement is received, it tries to receive that particular
       stream.

       Example command lines follow.

       To play back the first stream announced on the normal SAP multicast
       address:

               avplay sap://

       To play back the first stream announced on one the default IPv6 SAP
       multicast address:

               avplay sap://[ff0e::2:7ffe]

   tcp
       Trasmission Control Protocol.

       The required syntax for a TCP url is:

               tcp://<hostname>:<port>[?<options>]

       listen
           Listen for an incoming connection

                   avconv -i <input> -f <format> tcp://<hostname>:<port>?listen
                   avplay tcp://<hostname>:<port>

   tls
       Transport Layer Security (TLS) / Secure Sockets Layer (SSL)

       The required syntax for a TLS url is:

               tls://<hostname>:<port>

       The following parameters can be set via command line options (or in
       code via "AVOption"s):

       ca_file
           A file containing certificate authority (CA) root certificates to
           treat as trusted. If the linked TLS library contains a default this
           might not need to be specified for verification to work, but not
           all libraries and setups have defaults built in.

       tls_verify=1|0
           If enabled, try to verify the peer that we are communicating with.
           Note, if using OpenSSL, this currently only makes sure that the
           peer certificate is signed by one of the root certificates in the
           CA database, but it does not validate that the certificate actually
           matches the host name we are trying to connect to. (With GnuTLS,
           the host name is validated as well.)

           This is disabled by default since it requires a CA database to be
           provided by the caller in many cases.

       cert_file
           A file containing a certificate to use in the handshake with the
           peer.  (When operating as server, in listen mode, this is more
           often required by the peer, while client certificates only are
           mandated in certain setups.)

       key_file
           A file containing the private key for the certificate.

       listen=1|0
           If enabled, listen for connections on the provided port, and assume
           the server role in the handshake instead of the client role.

   udp
       User Datagram Protocol.

       The required syntax for a UDP url is:

               udp://<hostname>:<port>[?<options>]

       options contains a list of &-separated options of the form key=val.
       Follow the list of supported options.

       buffer_size=size
           set the UDP buffer size in bytes

       localport=port
           override the local UDP port to bind with

       localaddr=addr
           Choose the local IP address. This is useful e.g. if sending
           multicast and the host has multiple interfaces, where the user can
           choose which interface to send on by specifying the IP address of
           that interface.

       pkt_size=size
           set the size in bytes of UDP packets

       reuse=1|0
           explicitly allow or disallow reusing UDP sockets

       ttl=ttl
           set the time to live value (for multicast only)

       connect=1|0
           Initialize the UDP socket with "connect()". In this case, the
           destination address can't be changed with ff_udp_set_remote_url
           later.  If the destination address isn't known at the start, this
           option can be specified in ff_udp_set_remote_url, too.  This allows
           finding out the source address for the packets with getsockname,
           and makes writes return with AVERROR(ECONNREFUSED) if "destination
           unreachable" is received.  For receiving, this gives the benefit of
           only receiving packets from the specified peer address/port.

       sources=address[,address]
           Only receive packets sent to the multicast group from one of the
           specified sender IP addresses.

       block=address[,address]
           Ignore packets sent to the multicast group from the specified
           sender IP addresses.

       Some usage examples of the udp protocol with avconv follow.

       To stream over UDP to a remote endpoint:

               avconv -i <input> -f <format> udp://<hostname>:<port>

       To stream in mpegts format over UDP using 188 sized UDP packets, using
       a large input buffer:

               avconv -i <input> -f mpegts udp://<hostname>:<port>?pkt_size=188&buffer_size=65535

       To receive over UDP from a remote endpoint:

               avconv -i udp://[<multicast-address>]:<port>

   unix
       Unix local socket

       The required syntax for a Unix socket URL is:

               unix://<filepath>

       The following parameters can be set via command line options (or in
       code via "AVOption"s):

       timeout
           Timeout in ms.

       listen
           Create the Unix socket in listening mode.

       Input devices are configured elements in Libav which allow to access
       the data coming from a multimedia device attached to your system.

       When you configure your Libav build, all the supported input devices
       are enabled by default. You can list all available ones using the
       configure option "--list-indevs".

       You can disable all the input devices using the configure option
       "--disable-indevs", and selectively enable an input device using the
       option "--enable-indev=INDEV", or you can disable a particular input
       device using the option "--disable-indev=INDEV".

       The option "-formats" of the av* tools will display the list of
       supported input devices (amongst the demuxers).

       A description of the currently available input devices follows.

   alsa
       ALSA (Advanced Linux Sound Architecture) input device.

       To enable this input device during configuration you need libasound
       installed on your system.

       This device allows capturing from an ALSA device. The name of the
       device to capture has to be an ALSA card identifier.

       An ALSA identifier has the syntax:

               hw:<CARD>[,<DEV>[,<SUBDEV>]]

       where the DEV and SUBDEV components are optional.

       The three arguments (in order: CARD,DEV,SUBDEV) specify card number or
       identifier, device number and subdevice number (-1 means any).

       To see the list of cards currently recognized by your system check the
       files /proc/asound/cards and /proc/asound/devices.

       For example to capture with avconv from an ALSA device with card id 0,
       you may run the command:

               avconv -f alsa -i hw:0 alsaout.wav

       For more information see:
       <http://www.alsa-project.org/alsa-doc/alsa-lib/pcm.html>

   bktr
       BSD video input device.

   dv1394
       Linux DV 1394 input device.

   fbdev
       Linux framebuffer input device.

       The Linux framebuffer is a graphic hardware-independent abstraction
       layer to show graphics on a computer monitor, typically on the console.
       It is accessed through a file device node, usually /dev/fb0.

       For more detailed information read the file
       Documentation/fb/framebuffer.txt included in the Linux source tree.

       To record from the framebuffer device /dev/fb0 with avconv:

               avconv -f fbdev -r 10 -i /dev/fb0 out.avi

       You can take a single screenshot image with the command:

               avconv -f fbdev -frames:v 1 -r 1 -i /dev/fb0 screenshot.jpeg

       See also <http://linux-fbdev.sourceforge.net/>, and fbset(1).

   jack
       JACK input device.

       To enable this input device during configuration you need libjack
       installed on your system.

       A JACK input device creates one or more JACK writable clients, one for
       each audio channel, with name client_name:input_N, where client_name is
       the name provided by the application, and N is a number which
       identifies the channel.  Each writable client will send the acquired
       data to the Libav input device.

       Once you have created one or more JACK readable clients, you need to
       connect them to one or more JACK writable clients.

       To connect or disconnect JACK clients you can use the jack_connect and
       jack_disconnect programs, or do it through a graphical interface, for
       example with qjackctl.

       To list the JACK clients and their properties you can invoke the
       command jack_lsp.

       Follows an example which shows how to capture a JACK readable client
       with avconv.

               # Create a JACK writable client with name "libav".
               $ avconv -f jack -i libav -y out.wav

               # Start the sample jack_metro readable client.
               $ jack_metro -b 120 -d 0.2 -f 4000

               # List the current JACK clients.
               $ jack_lsp -c
               system:capture_1
               system:capture_2
               system:playback_1
               system:playback_2
               libav:input_1
               metro:120_bpm

               # Connect metro to the avconv writable client.
               $ jack_connect metro:120_bpm libav:input_1

       For more information read: <http://jackaudio.org/>

   libdc1394
       IIDC1394 input device, based on libdc1394 and libraw1394.

   oss
       Open Sound System input device.

       The filename to provide to the input device is the device node
       representing the OSS input device, and is usually set to /dev/dsp.

       For example to grab from /dev/dsp using avconv use the command:

               avconv -f oss -i /dev/dsp /tmp/oss.wav

       For more information about OSS see:
       <http://manuals.opensound.com/usersguide/dsp.html>

   pulse
       pulseaudio input device.

       To enable this input device during configuration you need libpulse-
       simple installed in your system.

       The filename to provide to the input device is a source device or the
       string "default"

       To list the pulse source devices and their properties you can invoke
       the command pactl list sources.

               avconv -f pulse -i default /tmp/pulse.wav

       server AVOption

       The syntax is:

               -server <server name>

       Connects to a specific server.

       name AVOption

       The syntax is:

               -name <application name>

       Specify the application name pulse will use when showing active
       clients, by default it is "libav"

       stream_name AVOption

       The syntax is:

               -stream_name <stream name>

       Specify the stream name pulse will use when showing active streams, by
       default it is "record"

       sample_rate AVOption

       The syntax is:

               -sample_rate <samplerate>

       Specify the samplerate in Hz, by default 48kHz is used.

       channels AVOption

       The syntax is:

               -channels <N>

       Specify the channels in use, by default 2 (stereo) is set.

       frame_size AVOption

       The syntax is:

               -frame_size <bytes>

       Specify the number of byte per frame, by default it is set to 1024.

       fragment_size AVOption

       The syntax is:

               -fragment_size <bytes>

       Specify the minimal buffering fragment in pulseaudio, it will affect
       the audio latency. By default it is unset.

   sndio
       sndio input device.

       To enable this input device during configuration you need libsndio
       installed on your system.

       The filename to provide to the input device is the device node
       representing the sndio input device, and is usually set to /dev/audio0.

       For example to grab from /dev/audio0 using avconv use the command:

               avconv -f sndio -i /dev/audio0 /tmp/oss.wav

   video4linux2
       Video4Linux2 input video device.

       The name of the device to grab is a file device node, usually Linux
       systems tend to automatically create such nodes when the device (e.g.
       an USB webcam) is plugged into the system, and has a name of the kind
       /dev/videoN, where N is a number associated to the device.

       Video4Linux2 devices usually support a limited set of widthxheight
       sizes and framerates. You can check which are supported using
       -list_formats all for Video4Linux2 devices.

       Some usage examples of the video4linux2 devices with avconv and avplay:

               # Grab and show the input of a video4linux2 device.
               avplay -f video4linux2 -framerate 30 -video_size hd720 /dev/video0

               # Grab and record the input of a video4linux2 device, leave the
               framerate and size as previously set.
               avconv -f video4linux2 -input_format mjpeg -i /dev/video0 out.mpeg

   vfwcap
       VfW (Video for Windows) capture input device.

       The filename passed as input is the capture driver number, ranging from
       0 to 9. You may use "list" as filename to print a list of drivers. Any
       other filename will be interpreted as device number 0.

   x11grab
       X11 video input device.

       This device allows to capture a region of an X11 display.

       The filename passed as input has the syntax:

               [<hostname>]:<display_number>.<screen_number>[+<x_offset>,<y_offset>]

       hostname:display_number.screen_number specifies the X11 display name of
       the screen to grab from. hostname can be omitted, and defaults to
       "localhost". The environment variable DISPLAY contains the default
       display name.

       x_offset and y_offset specify the offsets of the grabbed area with
       respect to the top-left border of the X11 screen. They default to 0.

       Check the X11 documentation (e.g. man X) for more detailed information.

       Use the dpyinfo program for getting basic information about the
       properties of your X11 display (e.g. grep for "name" or "dimensions").

       For example to grab from :0.0 using avconv:

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

               # Grab at position 10,20.
               avconv -f x11grab -r 25 -s cif -i :0.0+10,20 out.mpg

       follow_mouse AVOption

       The syntax is:

               -follow_mouse centered|<PIXELS>

       When it is specified with "centered", the grabbing region follows the
       mouse pointer and keeps the pointer at the center of region; otherwise,
       the region follows only when the mouse pointer reaches within PIXELS
       (greater than zero) to the edge of region.

       For example:

               avconv -f x11grab -follow_mouse centered -r 25 -s cif -i :0.0 out.mpg

               # Follows only when the mouse pointer reaches within 100 pixels to edge
               avconv -f x11grab -follow_mouse 100 -r 25 -s cif -i :0.0 out.mpg

       show_region AVOption

       The syntax is:

               -show_region 1

       If show_region AVOption is specified with 1, then the grabbing region
       will be indicated on screen. With this option, it's easy to know what
       is being grabbed if only a portion of the screen is grabbed.

       For example:

               avconv -f x11grab -show_region 1 -r 25 -s cif -i :0.0+10,20 out.mpg

               # With follow_mouse
               avconv -f x11grab -follow_mouse centered -show_region 1  -r 25 -s cif -i :0.0 out.mpg

       avconv(1), avplay(1) and the Libav HTML documentation

       The Libav developers

                                  2016-02-19                        AVPROBE(1)

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