Provided by: sox_14.4.1-3ubuntu1_amd64 bug

NAME

       SoX - Sound eXchange, the Swiss Army knife of audio manipulation

DESCRIPTION

       This  manual  describes  SoX supported file formats and audio device types; the SoX manual
       set starts with sox(1).

       Format types that can SoX can determine by a filename  extension  are  listed  with  their
       names  preceded  by  a  dot.   Format  types that are optionally built into SoX are marked
       `(optional)'.

       Format types that can be handled by an external library via an optional pseudo  file  type
       (currently  sndfile  or  ffmpeg)  are marked e.g. `(also with -t sndfile)'.  This might be
       useful if you have a file that doesn't work with SoX's default format readers and writers,
       and there's an external reader or writer for that format.

       To  see if SoX has support for an optional format or device, enter sox -h and look for its
       name under the list: `AUDIO FILE FORMATS' or `AUDIO DEVICE DRIVERS'.

   SOX FORMATS & DEVICE DRIVERS
       .raw (also with -t sndfile), .f32, .f64, .s8, .s16, .s24, .s32,
       .u8, .u16, .u24, .u32, .ul, .al, .lu, .la
              Raw (headerless) audio files.  For raw, the sample rate and the data encoding  must
              be  given using command-line format options; for the other listed types, the sample
              rate defaults to 8kHz (but may be overridden), and the data encoding is defined  by
              the  given  suffix.  Thus f32 and f64 indicate files encoded as 32 and 64-bit (IEEE
              single and double precision) floating point PCM respectively; s8, s16, s24, and s32
              indicate  8,  16, 24, and 32-bit signed integer PCM respectively; u8, u16, u24, and
              u32 indicate 8, 16, 24, and 32-bit unsigned integer PCM respectively; ul  indicates
              `μ-law'  (8-bit), al indicates `A-law' (8-bit), and lu and la are inverse bit order
              `μ-law' and inverse bit order `A-law'  respectively.   For  all  raw  formats,  the
              number of channels defaults to 1 (but may be overridden).

              Headerless  audio  files  on  a SPARC computer are likely to be of format ul;  on a
              Mac, they're likely to be u8 but with a sample rate of 11025 or 22050 Hz.

              See .ima and .vox for raw ADPCM formats, and .cdda for raw CD digital audio.

       .f4, .f8, .s1, .s2, .s3, .s4,
       .u1, .u2, .u3, .u4, .sb, .sw, .sl, .ub, .uw
              Deprecated aliases for f32, f64, s8, s16, s24, s32,
              u8, u16, u24, u32, s8, s16, s32, u8, and u16 respectively.

       .8svx (also with -t sndfile)
              Amiga 8SVX musical instrument description format.

       .aiff, .aif (also with -t sndfile)
              AIFF files as used on old Apple Macs, Apple IIc/IIgs and SGI.  SoX's  AIFF  support
              does  not include multiple audio chunks, or the 8SVX musical instrument description
              format.  AIFF files are multimedia archives and can have multiple audio and picture
              chunks  -  you may need a separate archiver to work with them.  With Mac OS X, AIFF
              has been superseded by CAF.

       .aiffc, .aifc (also with -t sndfile)
              AIFF-C is a format based on AIFF that was  created  to  allow  handling  compressed
              audio.   It  can  also  handle little endian uncompressed linear data that is often
              referred to as sowt encoding.  This encoding has also  become  the  defacto  format
              produced  by  modern Macs as well as iTunes on any platform.  AIFF-C files produced
              by other applications typically have the file extension .aif and require looking at
              its  header to detect the true format.  The sowt encoding is the only encoding that
              SoX can handle with this format.

              AIFF-C is defined in DAVIC 1.4 Part 9 Annex B.  This format is referred  from  ARIB
              STD-B24, which is specified for Japanese data broadcasting.  Any private chunks are
              not supported.

       alsa (optional)
              Advanced  Linux  Sound  Architecture  device  driver;  supports  both  playing  and
              recording  audio.  ALSA is only used in Linux-based operating systems, though these
              often support OSS (see below) as well.  Examples:
                   sox infile -t alsa
                   sox infile -t alsa default
                   sox infile -t alsa plughw:0,0
                   sox -2 -t alsa hw:1 outfile
              See also play(1), rec(1), and sox(1) -d.

       .amb   Ambisonic B-Format: a specialisation of .wav with between  3  and  16  channels  of
              audio       for       use       with      an      Ambisonic      decoder.       See
              http://www.ambisonia.com/Members/mleese/file-format-for-b-format for  details.   It
              is  up  to  the  user  to  get  the channels together in the right order and at the
              correct amplitude.

       .amr-nb (optional)
              Adaptive Multi Rate - Narrow  Band  speech  codec;  a  lossy  format  used  in  3rd
              generation mobile telephony and defined in 3GPP TS 26.071 et al.

              AMR-NB  audio  has  a  fixed  sampling  rate  of 8 kHz and supports encoding to the
              following bit-rates (as selected by the -C option): 0  =  4.75  kbit/s,  1  =  5.15
              kbit/s,  2  =  5.9 kbit/s, 3 = 6.7 kbit/s, 4 = 7.4 kbit/s 5 = 7.95 kbit/s, 6 = 10.2
              kbit/s, 7 = 12.2 kbit/s.

       .amr-wb (optional)
              Adaptive Multi Rate - Wide Band speech codec; a lossy format used in 3rd generation
              mobile telephony and defined in 3GPP TS 26.171 et al.

              AMR-WB  audio  has  a  fixed  sampling  rate of 16 kHz and supports encoding to the
              following bit-rates (as selected by the -C option):  0  =  6.6  kbit/s,  1  =  8.85
              kbit/s,  2 = 12.65 kbit/s, 3 = 14.25 kbit/s, 4 = 15.85 kbit/s 5 = 18.25 kbit/s, 6 =
              19.85 kbit/s, 7 = 23.05 kbit/s, 8 = 23.85 kbit/s.

       ao (optional)
              Xiph.org's Audio Output device driver; works only for playing audio.  It supports a
              wide range of devices and sound systems - see its documentation for the full range.
              For the most part, SoX's use of libao cannot be configured directly; instead, libao
              configuration files must be used.

              The  filename  specified is used to determine which libao plugin to use.  Normally,
              you should specify `default' as the filename.  If that  doesn't  give  the  desired
              behavior  then you can specify the short name for a given plugin (such as pulse for
              pulse audio plugin).  Examples:
                   sox infile -t ao
                   sox infile -t ao default
                   sox infile -t ao pulse
              See also play(1) and sox(1) -d.

       .au, .snd (also with -t sndfile)
              Sun Microsystems AU files.  There are many types of AU file; DEC has  invented  its
              own  with a different magic number and byte order.  To write a DEC file, use the -L
              option with the output file options.

              Some .au files are known to have invalid AU headers; these  are  probably  original
              Sun μ-law 8000 Hz files and can be dealt with using the .ul format (see below).

              It  is  possible to override AU file header information with the -r and -c options,
              in which case SoX will issue a warning to that effect.

       .avr   Audio Visual Research format; used by a number of commercial packages on the Mac.

       .caf (optional)
              Apple's Core Audio File format.

       .cdda, .cdr
              `Red Book' Compact Disc Digital Audio (raw audio).  CDDA  has  two  audio  channels
              formatted  as 16-bit signed integers (big endian)at a sample rate of 44.1 kHz.  The
              number of (stereo) samples in each CDDA track is always a multiple of 588.

       coreaudio (optional)
              Mac OSX CoreAudio device driver: supports both playing and recording audio.   If  a
              filename  is not specific or if the name is "default" then the default audio device
              is selected.  Any other name will be used to select a specific device.   The  valid
              names  can  be seen in the System Preferences->Sound menu and then under the Output
              and Input tabs.

              Examples:
                   sox infile -t coreaudio
                   sox infile -t coreaudio default
                   sox infile -t coreaudio "Internal Speakers"
              See also play(1), rec(1), and sox(1) -d.

       .cvsd, .cvs
              Continuously Variable Slope Delta modulation.  A headerless format used to compress
              speech  audio  for  applications such as voice mail.  This format is sometimes used
              with bit-reversed samples - the -X format option can be used to set the bit-order.

       .cvu   Continuously Variable Slope Delta modulation (unfiltered).  This is an  alternative
              handler for CVSD that is unfiltered but can be used with any bit-rate.  E.g.
                   sox infile outfile.cvu rate 28k
                   play -r 28k outfile.cvu sinc -3.4k

       .dat   Text  Data files.  These files contain a textual representation of the sample data.
              There is one line at the beginning that contains the sample rate, and one line that
              contains the number of channels.  Subsequent lines contain two or more numeric data
              intems: the time since the beginning of the first sample and the sample  value  for
              each channel.

              Values  are  normalized  so  that  the maximum and minimum are 1 and -1.  This file
              format can be used to create data files for external programs such as FFT analysers
              or graph routines.  SoX can also convert a file in this format back into one of the
              other file formats.

              Example containing only 2 stereo samples of silence:

                  ; Sample Rate 8012
                  ; Channels 2
                              0   0    0
                  0.00012481278   0    0

       .dvms, .vms
              Used in Germany to compress speech audio for voice mail.  A self-describing variant
              of cvsd.

       .fap (optional)
              See .paf.

       ffmpeg (optional)
              This  is  a  pseudo-type  that  forces  ffmpeg  to be used. The actual file type is
              deduced from the file name (it cannot be used on stdio).  It can read a wide  range
              of  audio  files, not all of which are documented here, and also the audio track of
              many video files (including AVI, WMV and MPEG). At present  only  the  first  audio
              track of a file can be read.

       .flac (optional; also with -t sndfile)
              Xiph.org's  Free  Lossless  Audio CODEC compressed audio.  FLAC is an open, patent-
              free CODEC designed for compressing music.  It is similar to MP3  and  Ogg  Vorbis,
              but lossless, meaning that audio is compressed in FLAC without any loss in quality.

              SoX  can  read  native  FLAC files (.flac) but not Ogg FLAC files (.ogg).  [But see
              .ogg below for information relating to support for Ogg Vorbis files.]

              SoX can write native FLAC files according to a given or default compression  level.
              8  is the default compression level and gives the best (but slowest) compression; 0
              gives the least (but fastest) compression.  The compression level is selected using
              the -C option [see sox(1)] with a whole number from 0 to 8.

       .fssd  An alias for the .u8 format.

       .gsrt  Grandstream  ring-tone  files.   Whilst  this file format can contain A-Law, μ-law,
              GSM, G.722, G.723, G.726, G.728, or iLBC encoded audio, SoX  supports  reading  and
              writing only A-Law and μ-law.  E.g.
                 sox music.wav -t gsrt ring.bin
                 play ring.bin

       .gsm (optional; also with -t sndfile)
              GSM 06.10 Lossy Speech Compression.  A lossy format for compressing speech which is
              used in the Global Standard for Mobile telecommunications (GSM).  It's good for its
              purpose,  shrinking  audio  data  size,  but it will introduce lots of noise when a
              given audio signal is encoded and decoded multiple times.  This format is  used  by
              some voice mail applications.  It is rather CPU intensive.

       .hcom  Macintosh HCOM files.  These are Mac FSSD files with Huffman compression.

       .htk   Single  channel 16-bit PCM format used by HTK, a toolkit for building Hidden Markov
              Model speech processing tools.

       .ircam (also with -t sndfile)
              Another name for .sf.

       .ima (also with -t sndfile)
              A headerless file of IMA ADPCM audio data. IMA ADPCM claims 16-bit precision packed
              into only 4 bits, but in fact sounds no better than .vox.

       .lpc, .lpc10
              LPC-10  is  a  compression  scheme  for  speech developed in the United States. See
              http://www.arl.wustl.edu/~jaf/lpc/ for details. There is no associated file format,
              so SoX's implementation is headerless.

       .mat, .mat4, .mat5 (optional)
              Matlab  4.2/5.0  (respectively  GNU  Octave  2.0/2.1)  format  (.mat is the same as
              .mat4).

       .m3u   A playlist format; contains a list of audio files.  SoX can  read,  but  not  write
              this file format.  See [1] for details of this format.

       .maud  An  IFF-conforming  audio  file  type,  registered by MS MacroSystem Computer GmbH,
              published along with the `Toccata' sound-card on the Amiga.   Allows  8bit  linear,
              16bit linear, A-Law, μ-law in mono and stereo.

       .mp3, .mp2 (optional read, optional write)
              MP3  compressed  audio;  MP3 (MPEG Layer 3) is a part of the patent-encumbered MPEG
              standards for audio and video compression.  It is a lossy compression  format  that
              achieves good compression rates with little quality loss.

              Because  MP3  is  patented,  SoX  cannot  be  distributed  with MP3 support without
              incurring the patent holder's fees.  Users who require SoX with  MP3  support  must
              currently  compile  and  build  SoX with the MP3 libraries (LAME & MAD) from source
              code, or, in some cases, obtain pre-built dynamically loadable libraries.

              When reading MP3 files, up to 28 bits of precision is stored although only 16  bits
              is  reported  to  user.  This is to allow default behavior of writing 16 bit output
              files.  A user can specify a higher  precision  for  the  output  file  to  prevent
              lossing  this  extra  information.   MP3  output  files  will  use up to 24 bits of
              precision while encoding.

              MP3 compression parameters can be selected using SoX's -C option as  follows  (note
              that the current syntax is subject to change):

              The  primary  parameter to the LAME encoder is the bit rate. If the value of the -C
              value is a positive integer, it's taken as the bitrate in kbps (e.g. if you specify
              128, it uses 128 kbps).

              The  second  most  important  parameter is probably "quality" (really performance),
              which allows balancing encoding speed vs. quality.  In LAME,  0  specifies  highest
              quality  but  is  very  slow,  while 9 selects poor quality, but is fast. (5 is the
              default and 2 is recommended as a good trade-off for high quality encodes.)

              Because the -C value is a float, the fractional part is  used  to  select  quality.
              128.2 selects 128 kbps encoding with a quality of 2. There is one problem with this
              approach. We need 128 to specify 128 kbps encoding with default quality, so 0 means
              use  default.  Instead  of  0  you  have to use .01 (or .99) to specify the highest
              quality (128.01 or 128.99).

              LAME uses bitrate to specify a constant bitrate, but higher quality can be achieved
              using Variable Bit Rate (VBR). VBR quality (really size) is selected using a number
              from 0 to 9. Use a value of 0 for high quality, larger files,  and  9  for  smaller
              files of lower quality. 4 is the default.

              In  order  to  squeeze  the  selection  of  VBR  into the the -C value float we use
              negative numbers to select VRR. -4.2 would select default VBR encoding (size)  with
              high  quality  (speed).  One  special  case  is  0,  which  is a valid VBR encoding
              parameter but not a valid bitrate.  Compression value of 0 is always treated  as  a
              high  quality vbr, as a result both -0.2 and 0.2 are treated as highest quality VBR
              (size) and high quality (speed).

              See also Ogg Vorbis for a similar format.

       .mp4, .m4a (optional)
              MP4 compressed audio.  MP3 (MPEG 4) is part of the MPEG  standards  for  audio  and
              video compression.  See mp3 for more information.

       .nist (also with -t sndfile)
              See .sph.

       .ogg, .vorbis (optional)
              Xiph.org's  Ogg  Vorbis  compressed  audio; an open, patent-free CODEC designed for
              music and streaming audio.  It is a lossy compression format (similar to MP3, VQF &
              AAC) that achieves good compression rates with a minimum amount of quality loss.

              SoX  can  decode  all  types  of  Ogg  Vorbis  files,  and  can encode at different
              compression levels/qualities given as a number from -1 (highest  compression/lowest
              quality)  to  10  (lowest  compression,  highest quality).  By default the encoding
              quality level is 3 (which gives an encoded rate of approx. 112kbps), but  this  can
              be  changed using the -C option (see above) with a number from -1 to 10; fractional
              numbers (e.g.  3.6) are also allowed.   Decoding  is  somewhat  CPU  intensive  and
              encoding is very CPU intensive.

              See also .mp3 for a similar format.

       oss (optional)
              Open  Sound  System  /dev/dsp  device  driver;  supports both playing and recording
              audio.  OSS support is available in Unix-like operating systems, sometimes together
              with alternative sound systems (such as ALSA).  Examples:
                   sox infile -t oss
                   sox infile -t oss /dev/dsp
                   sox -2 -t oss /dev/dsp outfile
              See also play(1), rec(1), and sox(1) -d.

       .paf, .fap (optional)
              Ensoniq PARIS file format (big and little-endian respectively).

       .pls   A  playlist  format;  contains  a list of audio files.  SoX can read, but not write
              this file format.  See [2] for details of this format.

              Note: SoX support for SHOUTcast  PLS  relies  on  wget(1)  and  is  only  partially
              supported: it's necessary to specify the audio type manually, e.g.
                   play -t mp3 "http://a.server/pls?rn=265&file=filename.pls"
              and  SoX  does  not  know  about  alternative  servers  - hit Ctrl-C twice in quick
              succession to quit.

       .prc   Psion Record. Used in Psion EPOC PDAs (Series  5,  Revo  and  similar)  for  System
              alarms  and  recordings made by the built-in Record application.  When writing, SoX
              defaults to A-law, which is recommended; if you must use ADPCM,  then  use  the  -i
              switch. The sound quality is poor because Psion Record seems to insist on frames of
              800 samples or fewer, so that the ADPCM CODEC has to be reset at every 800  frames,
              which causes the sound to glitch every tenth of a second.

       pulseaudio (optional)
              PulseAudio  driver;  supports both playing and recording of audio.  PulseAudio is a
              cross platform networked sound server.  If a  file  name  is  specified  with  this
              driver, it is ignored.  Examples:
                   sox infile -t pulseaudio
                   sox infile -t pulseaudio default
              See also play(1), rec(1), and sox(1) -d.

       .pvf (optional)
              Portable Voice Format.

       .sd2 (optional)
              Sound Designer 2 format.

       .sds (optional)
              MIDI Sample Dump Standard.

       .sf (also with -t sndfile)
              IRCAM   SDIF  (Institut  de  Recherche  et  Coordination  Acoustique/Musique  Sound
              Description Interchange Format). Used by academic music software such as the CSound
              package, and the MixView sound sample editor.

       .sln   Asterisk PBX `signed linear' 8khz, 16-bit signed integer, little-endian raw format.

       .sph, .nist (also with -t sndfile)
              SPHERE  (SPeech  HEader  Resources)  is  a  file  format  defined by NIST (National
              Institute of Standards and Technology) and is used with speech audio.  SoX can read
              these  files  when  they  contain  μ-law  and  PCM data.  It will ignore any header
              information that says the data is compressed using  shorten  compression  and  will
              treat  the  data  as either μ-law or PCM.  This will allow SoX and the command line
              shorten program to be run together using pipes to encompasses  the  data  and  then
              pass the result to SoX for processing.

       .smp   Turtle  Beach  SampleVision  files.   SMP files are for use with the PC-DOS package
              SampleVision by Turtle Beach Softworks.   This  package  is  for  communication  to
              several MIDI samplers.  All sample rates are supported by the package, although not
              all are supported by the samplers themselves.  Currently loop points are ignored.

       .snd   See .au, .sndr and .sndt.

       sndfile (optional)
              This is a pseudo-type that forces libsndfile to be used.  For  writing  files,  the
              actual  file  type is then taken from the output file name; for reading them, it is
              deduced from the file.

       sndio (optional)
              OpenBSD audio device driver; supports both playing and recording audio.
                   sox infile -t sndio
              See also play(1), rec(1), and sox(1) -d.

       .sndr  Sounder files.  An MS-DOS/Windows  format  from  the  early  '90s.   Sounder  files
              usually have the extension `.SND'.

       .sndt  SoundTool  files.   An  MS-DOS/Windows format from the early '90s.  SoundTool files
              usually have the extension `.SND'.

       .sou   An alias for the .u8 raw format.

       .sox   SoX's native uncompressed PCM format, intended for storing  (or  piping)  audio  at
              intermediate  processing  points  (i.e.  between  SoX invocations).  It has much in
              common with the popular WAV, AIFF, and AU uncompressed PCM  formats,  but  has  the
              following  specific  characteristics:  the  PCM samples are always stored as 32 bit
              signed integers, the samples are stored (by default) as `native  endian',  and  the
              number  of  samples in the file is recorded as a 64-bit integer.  Comments are also
              supported.

              See `Special Filenames' in sox(1) for  examples  of  using  the  .sox  format  with
              `pipes'.

       sunau (optional)
              Sun  /dev/audio  device  driver;  supports  both  playing and recording audio.  For
              example:
                   sox infile -t sunau /dev/audio
              or
                   sox infile -t sunau -U -c 1 /dev/audio
              for older sun equipment.

              See also play(1), rec(1), and sox(1) -d.

       .txw   Yamaha TX-16W sampler.  A file format from a Yamaha sampling keyboard  which  wrote
              IBM-PC format 3.5" floppies.  Handles reading of files which do not have the sample
              rate field set to one of the expected  by  looking  at  some  other  bytes  in  the
              attack/loop  length  fields,  and  defaulting to 33 kHz if the sample rate is still
              unknown.

       .vms   See .dvms.

       .voc (also with -t sndfile)
              Sound Blaster VOC files.  VOC files  are  multi-part  and  contain  silence  parts,
              looping,  and  different  sample rates for different chunks.  On input, the silence
              parts are filled out, loops are rejected, and sample data with a new sample rate is
              rejected.   Silence  with  a  different sample rate is generated appropriately.  On
              output, silence is not detected, nor are impossible  sample  rates.   SoX  supports
              reading  (but  not  writing)  VOC  files with multiple blocks, and files containing
              μ-law, A-law, and 2/3/4-bit ADPCM samples.

       .vorbis
              See .ogg.

       .vox (also with -t sndfile)
              A headerless file  of  Dialogic/OKI  ADPCM  audio  data  commonly  comes  with  the
              extension .vox.  This ADPCM data has 12-bit precision packed into only 4-bits.

              Note:  some  early Dialogic hardware does not always reset the ADPCM encoder at the
              start of each vox file.  This can result in clipping and/or DC offset problems when
              it comes to decoding the audio.  Whilst little can be done about the clipping, a DC
              offset can be removed by passing the decoded  audio  through  a  high-pass  filter,
              e.g.:
                   sox input.vox output.wav highpass 10

       .w64 (optional)
              Sonic Foundry's 64-bit RIFF/WAV format.

       .wav (also with -t sndfile)
              Microsoft  .WAV  RIFF  files.  This is the native audio file format of Windows, and
              widely used for uncompressed audio.

              Normally .wav files have all formatting information in their headers, and so do not
              need  any  format  options  specified  for  an  input  file.  If any are, they will
              override the file header, and you will be warned to this effect.   You  had  better
              know  what you are doing! Output format options will cause a format conversion, and
              the .wav will written appropriately.

              SoX can read and write linear PCM, floating point, μ-law, A-law, MS ADPCM, and  IMA
              (or  DVI)  ADPCM encoded samples.  WAV files can also contain audio encoded in many
              other ways (not currently supported with SoX) e.g. MP3; in some cases such  a  file
              can still be read by SoX by overriding the file type, e.g.
                 play -t mp3 mp3-encoded.wav
              Big  endian  versions  of  RIFF files, called RIFX, are also supported.  To write a
              RIFX file, use the -B option with the output file options.

       waveaudio (optional)
              MS-Windows native audio device driver.  Examples:
                   sox infile -t waveaudio
                   sox infile -t waveaudio default
                   sox infile -t waveaudio 1
                   sox infile -t waveaudio "High Definition Audio Device ("
              If the device name is omitted, -1, or default, then you  get  the  `Microsoft  Wave
              Mapper' device.  Wave Mapper means `use the system default audio devices'.  You can
              control what `default' means via the OS Control Panel.

              If the device name given is some other number, you get that audio device by  index;
              so  recording  with  device  name  0  would get the first input device (perhaps the
              microphone), 1 would get the second (perhaps line in), etc.  Playback using 0  will
              get the first output device (usually the only audio device).

              If  the  device  name given is something other than a number, SoX tries to match it
              (maximum 31 characters) against the names of the available devices.

              See also play(1), rec(1), and sox(1) -d.

       .wavpcm
              A non-standard, but widely used, variant of .wav.  Some applications cannot read  a
              standard WAV file header for PCM-encoded data with sample-size greater than 16-bits
              or with more than two channels, but can read a  non-standard  WAV  header.   It  is
              likely  that  such  applications will eventually be updated to support the standard
              header, but in the mean time, this SoX format can be used to create files with  the
              non-standard  header that should work with these applications.  (Note that SoX will
              automatically detect and read WAV files with the non-standard header.)

              The most common use of this file-type is likely to be along the following lines:
                   sox infile.any -t wavpcm -s outfile.wav

       .wv (optional)
              WavPack lossless audio compression.  Note that, when converting .wav to this format
              and back again, the RIFF header is not necessarily preserved losslessly (though the
              audio is).

       .wve (also with -t sndfile)
              Psion 8-bit A-law.  Used on Psion SIBO PDAs (Series 3 and similar).  This format is
              deprecated in SoX, but will continue to be used in libsndfile.

       .xa    Maxis  XA  files.  These are 16-bit ADPCM audio files used by Maxis games.  Writing
              .xa files is currently not supported, although adding write support should  not  be
              very difficult.

       .xi (optional)
              Fasttracker 2 Extended Instrument format.

SEE ALSO

       sox(1), soxi(1), libsox(3), octave(1), wget(1)

       The SoX web page at http://sox.sourceforge.net
       SoX scripting examples at http://sox.sourceforge.net/Docs/Scripts

   References
       [1]    Wikipedia, M3U, http://en.wikipedia.org/wiki/M3U

       [2]    Wikipedia, PLS, http://en.wikipedia.org/wiki/PLS_(file_format)

LICENSE

       Copyright 1998-2013 Chris Bagwell and SoX Contributors.
       Copyright 1991 Lance Norskog and Sundry Contributors.

AUTHORS

       Chris Bagwell (cbagwell@users.sourceforge.net).  Other authors and contributors are listed
       in the ChangeLog file that is distributed with the source code.