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SoX(1)									SoX(1)



NAME
       sox - Sound eXchange : universal sound sample translator

SYNOPSIS
       sox infile outfile

       sox [ general options ] [ format options ] infile
	   [ format options ] outfile
	   [ effect [ effect options ] ... ]

       soxmix infile1 infile2 outfile

       soxmix [ general options ] [ format options ] infile1
	   [ format options ] infile2
	   [ format options ] outfile
	   [ effect [ effect options ] ... ]


       General options:
	   [ -h ] [ -p ] [ -v volume ] [ -V ]

       Format options:
	   [ -t filetype ] [ -r rate ] [ -s/-u/-U/-A/-a/-i/-g/-f ]
	   [ -b/-w/-l/-d ]
	   [ -c channels ] [ -x ] [ -e ]

       Effects:
	   avg [ -l | -r | -f | -b | -1 | -2 | -3 | -4 | n,n,...,n ]
	   band [ -n ] center [ width ]
	   bandpass frequency bandwidth
	   bandreject frequency bandwidth
	   chorus gain-in gain out delay decay speed depth
		  -s | -t [ delay decay speed depth -s | -t ]
	   compand attack1,decay1[,attack2,decay2...]
		   in-dB1,out-dB1[,in-dB2,out-dB2...]
		   [ gain [ initial-volume [ delay ] ] ]
	   copy
	   dcshift shift [ limitergain ]
	   deemph
	   earwax
	   echo gain-in gain-out delay decay [ delay decay ... ]
	   echos gain-in gain-out delay decay [ delay decay ... ]
	   fade [ type ] fade-in-length
		[ stop-time [ fade-out-length ] ]
	   filter [ low ]-[ high ] [ window-len [ beta ]]
	   flanger gain-in gain-out delay decay speed < -s | -t >
	   highp frequency
	   highpass frequency
	   lowp frequency
	   lowpass frequency
	   map
	   mask
	   pan direction
	   phaser gain-in gain-out delay decay speed < -s | -t >
	   pick [ -1 | -2 | -3 | -4 | -l | -r | -f | -b ]
	   pitch shift [ width interpole fade ]
	   polyphase [ -w < nut / ham > ]
		     [	-width < long / short / # > ]
		     [ -cutoff # ]
	   rate
	   repeat count
	   resample [ -qs | -q | -ql ] [ rolloff [ beta ] ]
	   reverb gain-out reverb-time delay [ delay ... ]
	   reverse
	   silence above_periods [ duration threshold[ d | % ]
		   [ below_periods duration
		     threshold[ d | % ]]
	   speed [ -c ] factor
	   stat [ -s n ] [ -rms ] [ -v ] [ -d ]
	   stretch [ factor [ window fade shift fading ]
	   swap [ 1 2 | 1 2 3 4 ]
	   synth [ length ] type mix [ freq [ -freq2 ]
		 [ off ] [ ph ] [ p1 ] [ p2 ] [ p3 ]
	   trim start [ length ]
	   vibro speed [ depth ]
	   vol gain [ type [ limitergain ] ]

DESCRIPTION
       SoX is a command line program that can convert most popular audio files
       to most other popular audio file formats.  It can optionally change the
       audio  sample data type and apply one or more sound effects to the file
       during this translation.

       soxmix is functionally the same as the command line program sox	expect
       that  it	 takes two files as input and mixes the audio together to pro-
       duce a single file as output.  It has a	restriction  that  both	 input
       files must be of the same data type and sample rates.

       There are two types of audio files formats that SoX can work with.  The
       first are self-describing file formats.	These contain  a  header  that
       completely describe the characteristics of the audio data that follows.

       The second type are header-less data, or sometimes called raw data.   A
       user must pass enough information to SoX on the command line so that it
       knows what type of data it contains.

       Audio data can usually be totally described by four characteristics:

       rate	 The sample rate is in samples per second.   For  example,  CD
		 sample rates are at 44100.

       data size The  precision the data is stored in.	Most popular are 8-bit
		 bytes or 16-bit words.

       data encoding
		 What encoding the data type uses.  Examples are u-law, ADPCM,
		 or signed linear data.

       channels	 How  many channels are contained in the audio data.  Mono and
		 Stereo are the two most common.

       Please refer to the soxexam(1) manual page for a long description  with
       examples on how to use SoX with various types of file formats.

OPTIONS
       The option syntax is a little grotty, but in essence:

	    sox File.au file.wav

       translates  a  sound file in SUN Sparc .AU format into a Microsoft .WAV
       file, while

	    sox -v 0.5 file.au -r 12000 file.wav mask

       does the same format translation but also lowers the amplitude by  1/2,
       changes	the  sampling  rate to 12000 hertz, and applies the mask sound
       effect to the audio data.

       The following will mix two sound files together to to produce a	single
       sound file.

	       soxmix music.wav voice.wav mixed.wav

       Format options:

       Format  options effect the audio samples that they immediately precede.
       If they are placed before the input file	 name  then  they  effect  the
       input  data.   If they are placed before the output file name then they
       will effect the output data.  By taking	advantage  of  this,  you  can
       override a input file’s corrupted header or produce an output file that
       is totally different style then the input file.	It is also how SoX  is
       informed about the format of raw input data.

       -t filetype
		 gives	the  type  of the sound sample file.  Useful when file
		 extension is not standard or for specifying  the  .auto  file
		 type.

       -r rate	 Gives	the  sample  rate  in Hertz of the file.  To cause the
		 output file to have a different sample rate  than  the	 input
		 file, include this option as a part of the output options.
		 If  the  input	 and  output files have different rates then a
		 sample rate change effect must be  ran.   If  a  sample  rate
		 changing  effect  is  not  specified  then a default one will
		 internally be ran by SoX using its default parameters.

       -s/-u/-U/-A/-a/-i/-g/-f
		 The sample data encoding is signed linear  (2’s  complement),
		 unsigned  linear,  u-law  (logarithmic), A-law (logarithmic),
		 ADPCM, IMA_ADPCM, GSM, or Floating-point.
		 U-law (actually shorthand for mu-law) and A-law are the  U.S.
		 and  international  standards for logarithmic telephone sound
		 compression.  When uncompressed u-law has roughly the	preci-
		 sion  of 14-bit PCM audio and A-law has roughly the precision
		 of 13-bit PCM audio.
		 A-law and u-law data is sometimes encoded  using  a  reversed
		 bit-ordering  (ie.  MSB becomes LSB).	Internally, SoX under-
		 stands how to work with this encoding but there is  currently
		 no  command line option to specify it.	 If you need this sup-
		 port then you can use the psuedo  file	 types	of  ".la"  and
		 ".lu"	to  inform  sox	 of  the encoding.  See supported file
		 types for more information.
		 ADPCM is a form of sound compression that has a good  compro-
		 mise  between	good  sound quality and fast encoding/decoding
		 time.	It is used for telephone sound compression and	places
		 were full fidelity is not as important.  When uncompressed it
		 has roughly the precision of 16-bit PCM audio.	 Popular  ver-
		 sion of ADPCM include G.726, MS ADPCM, and IMA ADPCM.	The -a
		 flag has different meanings in different file	handlers.   In
		 .wav  files  it  represents  MS ADPCM files, in all others it
		 means G.726 ADPCM.  IMA ADPCM is a  specific  form  of	 ADPCM
		 compression,  slightly	 simpler  and  slightly lower fidelity
		 than Microsoft’s flavor of ADPCM.  IMA ADPCM is  also	called
		 DVI ADPCM.
		 GSM  is  a  standard  used for telephone sound compression in
		 European countries and its gaining popularity because of  its
		 quality.   It usually is CPU intensive to work with GSM audio
		 data.

       -b/-w/-l/-d
		 The sample data size is in bytes, 16-bit words,  32-bit  long
		 words, or 64-bit double long (long long) words.

       -x	 The  sample  data is in XINU format; that is, it comes from a
		 machine with the opposite word order than yours and  must  be
		 swapped  according to the word-size given above.  Only 16-bit
		 and 32-bit  integer  data  may	 be  swapped.	Machine-format
		 floating-point data is not portable.

       -c channels
		 The  number  of sound channels in the data file.  This may be
		 1, 2, or 4; for mono, stereo, or quad sound data.   To	 cause
		 the  output  file to have a different number of channels than
		 the input file, include this  option  with  the  output  file
		 options.   If the input and output file have a different num-
		 ber of channels then the avg effect must be used.  If the avg
		 effect	 is  not  specified  on	 the  command  line it will be
		 invoked internally with default parameters.

       -e	 When used after the input filename (so that it applies to the
		 output file) it allows you to avoid giving an output filename
		 and will not produce an output file.  It will apply any spec-
		 ified	effects to the input file.  This is mainly useful with
		 the stat effect but can be used with others.

       General options:

       -h	 Print version number and usage information.

       -p	 Run in preview mode and run fast.  This will  somewhat	 speed
		 up SoX when the output format has a different number of chan-
		 nels and a different rate than the  input  file.   Currently,
		 this  defaults to using the rate effect instead of the resam-
		 ple effect for sample rate changes.

       -v volume Change amplitude (floating point); less than  1.0  decreases,
		 greater  than	1.0  increases.	  May use a negative number to
		 invert the phase of the audio data.   It  is  interesting  to
		 note that we perceive volume logarithmically but this adjusts
		 the amplitude linearly.
		 Note: see the stat effect for information on finding the max-
		 imum  value that can be used with this option without causing
		 audio data be be clipped.

       -V	 Print a description of processing phases.  Useful for	figur-
		 ing out exactly how SoX is mangling your sound samples.

FILE TYPES
       SoX attempts to determine the file type of input files automatically by
       looking at the header of the audio file.	 When it is unable  to	detect
       the  file type or if its an output file then it uses the file extension
       of the file to determine what type of file format handler to use.  This
       can be overridden by specifying the "-t" option on the command line.

       The  input and output files may be read from standard in and out.  This
       is done by specifying ’-’ as the filename.

       File formats which have headers are checked,  if	 that  header  doesn’t
       seem right, the program exits with an appropriate message.

       The following file formats are supported:


       .8svx	 Amiga 8SVX musical instrument description format.

       .aiff	 AIFF  files  used  on Apple IIc/IIgs and SGI.	Note: the AIFF
		 format supports only one SSND chunk.	It  does  not  support
		 multiple   sound  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.

       .au	 SUN Microsystems AU files.  There are apparently  many	 types
		 of .au files; DEC has invented its own with a different magic
		 number and word order.	 The .au handler can read these	 files
		 but  will not write them.  Some .au files have valid AU head-
		 ers and some do not.  The latter are probably original SUN u-
		 law  8000  hz samples.	 These can be dealt with using the .ul
		 format (see below).

       .avr	 Audio Visual Research
		 The AVR format is produced by a number of commercial packages
		 on the Mac.

       .cdr	 CD-R
		 CD-R files are used in mastering music on Compact Disks.  The
		 audio data on a CD-R disk is a raw audio file with  a	format
		 of  stereo  16-bit  signed  samples  at  a 44khz sample rate.
		 There is a special blocking/padding oddity at the end of  the
		 audio file and is why it needs its own handler.

       .cvs	 Continuously Variable Slope Delta modulation
		 Used  to compress speech audio for applications such as voice
		 mail.

       .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.	Subsequent  lines  contain  two	 numeric  data
		 items:	 the  time since the beginning of the first sample and
		 the sample value.  Values are normalized so that the  maximum
		 and minimum are 1.00 and -1.00.  This file format can be used
		 to create data files for external programs such as  FFT  ana-
		 lyzers	 or  graph  routines.	SoX can also convert a file in
		 this format back into one of the other file formats.

       .gsm	 GSM 06.10 Lossy Speech Compression
		 A standard for compressing speech which is used in the Global
		 Standard  for	Mobil  telecommunications (GSM).  Its good for
		 its purpose, shrinking audio data size, but it will introduce
		 lots  of  noise  when	a  given  sound	 sample is encoded and
		 decoded multiple times.  This format is used  by  some	 voice
		 mail applications.  It is rather CPU intensive.
		 GSM in SoX is optional and requires access to an external GSM
		 library.  To see if there is support for gsm run sox  -h  and
		 look for it under the list of supported file formats.

       .hcom	 Macintosh  HCOM files.	 These are (apparently) Mac FSSD files
		 with some variant of Huffman compression.  The Macintosh  has
		 wacky file formats and this format handler apparently doesn’t
		 handle all the ones it should.	  Mac  users  will  need  your
		 usual	arsenal	 of  file converters to deal with an HCOM file
		 under Unix or DOS.

       .maud	 An Amiga format
		 An IFF-conform sound 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, u-law
		 in mono and stereo.

       .mp3	 MP3 Compressed Audio
		 MP3  audio  files  come from the MPEG standards for audio and
		 video compression.  They are a lossy compression format  that
		 achieves  good	 compression  rates  with  a minimum amount of
		 quality loss.	Also see Ogg Vorbis for a similar format.  MP3
		 support  in  SoX is optional and requires access to either or
		 both the external libmad and libmp3lame libraries.  To see if
		 there is support for Mp3 run sox -h and look for it under the
		 list of supported file formats as "mp3".


       .nul	 Null file handler.  This is a fake file hander that act as if
		 its reading a stream of 0’s from a while or fake writing out-
		 put to a file.	 This is not a very  useful  file  handler  in
		 most  cases.	It might be useful in some scripts were you do
		 not want to read or write from a real file but would like  to
		 specify a filename for consistency.

       .ogg	 Ogg Vorbis Compressed Audio.
		 Ogg  Vorbis  is  a  open, patent-free CODEC designed for com-
		 pressing music and streaming audio.  It is  similar  to  MP3,
		 VQF,  AAC, and other lossy formats.  SoX can decode all types
		 of Ogg Vorbis files, but can only encode at 128 kbps.	Decod-
		 ing is somewhat CPU intensive and encoding is very CPU inten-
		 sive.
		 Ogg Vorbis in SoX is optional and requires access to external
		 Ogg  Vorbis  libraries.   To  see if there is support for Ogg
		 Vorbis run sox -h and look for it under the list of supported
		 file formats as "vorbis".

       ossdsp	 OSS /dev/dsp device driver
		 This  is  a  pseudo-file  type and can be optionally compiled
		 into SoX.  Run sox -h to see if you  have  support  for  this
		 file type.  When this driver is used it allows you to open up
		 the OSS /dev/dsp file and configure it to use the  same  data
		 format	 as  passed  in to SoX.	 It works for both playing and
		 recording  sound  samples.   When  playing  sound  files   it
		 attempts  to  set up the OSS driver to use the same format as
		 the input file.  It is suggested to always override the  out-
		 put values to use the highest quality samples your sound card
		 can handle.  Example: -t ossdsp -w -s /dev/dsp

       .prc	 Psion record.app
		 Used in some Psion devices for System alarms.	This format is
		 newer	then  the  .wve	 format	 that  is  used	 in some Psion
		 devices.

       .sf	 IRCAM Sound Files.
		 Sound Files are used by academic music software such  as  the
		 CSound package, and the MixView sound sample editor.

       .sph
		 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 u-law and PCM data.  It will ignore any header infor-
		 mation	 that  says  the data is compressed using shorten com-
		 pression and will treat the data  as  either  u-law  or  PCM.
		 This  will  allow SoX and the command line shorten program to
		 be ran together using pipes to uncompress 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 them-
		 selves. Currently loop points are ignored.

       .snd
		 Under	DOS  this file format is the same as the .sndt format.
		 Under all other platforms it is the same as the .au format.

       .sndt	 SoundTool files.
		 This is an older DOS file format.

       sunau	 Sun /dev/audio device driver
		 This is a pseudo-file type and	 can  be  optionally  compiled
		 into  SoX.   Run  sox	-h to see if you have support for this
		 file type.  When this driver is used it allows you to open up
		 a  Sun	 /dev/audio file and configure it to use the same data
		 type as passed in to SoX.  It	works  for  both  playing  and
		 recording   sound  samples.   When  playing  sound  files  it
		 attempts to set up the audio driver to use the same format as
		 the  input file.  It is suggested to always override the out-
		 put values to use the highest quality samples	your  hardware
		 can  handle.	Example: -t sunau -w -s /dev/audio or -t sunau
		 -U -c 1 /dev/audio for older sun equipment.

       .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 33kHz if the sample rate  is	 still
		 unknown.

       .vms	 More info to come.
		 Used  to compress speech audio for applications such as voice
		 mail.

       .voc	 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  out-
		 put,  silence	is  not	 detected,  nor	 are impossible sample
		 rates.	 Note, this version now	 supports  playing  VOC	 files
		 with multiple blocks and supports playing files containing u-
		 law and A-law samples.

       vorbis	 See .ogg format.

       vox	 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.

       .wav	 Microsoft .WAV RIFF files.
		 These appear to be very similar to IFF	 files,	 but  not  the
		 same.	 They  are  the	 native	 sound file format of Windows.
		 (Obviously, Windows was of such incredible importance to  the
		 computer industry that it just had to have its own sound file
		 format.)  Normally .wav files have all formatting information
		 in their headers, and so do not need any format options spec-
		 ified 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 appro-
		 priately.  SoX currently can read PCM, ULAW, ALAW, MS	ADPCM,
		 and  IMA  (or	DVI) ADPCM.  It can write all of these formats
		 including (NEW!)  the ADPCM encoding.

       .wve	 Psion 8-bit A-law
		 These are 8-bit A-law 8khz sound  files  used	on  the	 Psion
		 palmtop portable computer.

       .raw	 Raw files (no header).
		 The  sample  rate,  size  (byte,  word,  etc),	 and  encoding
		 (signed, unsigned, etc.)  of the sample file must  be	given.
		 The number of channels defaults to 1.

       .ub, .sb, .uw, .sw, .ul, .al, .lu, .la, .sl
		 These are several suffices which serve as a shorthand for raw
		 files with a given size and encoding.	Thus, ub, sb, uw,  sw,
		 ul,  al, lu, la and sl correspond to "unsigned byte", "signed
		 byte", "unsigned word", "signed word",	 "u-law"  (byte),  "A-
		 law" (byte), inverse bit order "u-law", inverse bit order "A-
		 law", and "signed long".  The sample rate defaults to 8000 hz
		 if not explicitly set, and the number of channels defaults to
		 1.  There are lots of Sparc samples floating around in	 u-law
		 format	 with no header and fixed at a sample rate of 8000 hz.
		 (Certain sound management  software  cheerfully  ignores  the
		 headers.)   Similarly,	 most  Mac sound files are in unsigned
		 byte format with a sample rate of 11025 or 22050 hz.

       .auto	 This is a ‘‘meta-type’’: specifying this type	for  an	 input
		 file  triggers some code that tries to guess the real type by
		 looking for magic words in the header.	 If the type can’t  be
		 guessed,  the program exits with an error message.  The input
		 must be a plain file, not a pipe.  This type  can’t  be  used
		 for output files.

EFFECTS
       Multiple	 effects  may  be applied to the audio data by specifying them
       one after another at the end of the command line.

       avg [ -l | -r | -f | -b | -1 | -2 | -3 | -4 | n,n,...,n ]
		 Reduce the number of channels by averaging  the  samples,  or
		 duplicate  channels to increase the number of channels.  This
		 effect is automatically used when the number of  input	 chan-
		 nels  differ from the number of output channels.  When reduc-
		 ing the number of channels it is possible to manually specify
		 the  avg  effect  and use the -l, -r, -f, -b, -1, -2, -3, -4,
		 options to select only the left,  right,  front,  back	 chan-
		 nel(s)	 or specific channel for the output instead of averag-
		 ing the channels.  The -l, and -r options will	 do  averaging
		 in  quad-channel files so select the exact channel to prevent
		 this.

		 The avg effect can also be invoked with up to 16  double-pre-
		 cision	 numbers,  which  specify the proportion (0.0 = 0% and
		 1.0 = 100%) of each input channel that is to  be  mixed  into
		 each  output  channel.	  In  two-channel  mode, 4 numbers are
		 given: l->l, l->r, r->l, and r->r,  respectively.   In	 four-
		 channel  mode,	 the  first 4 numbers give the proportions for
		 the left-front output channel, as  follows:  lf->lf,  rf->lf,
		 lb->lf,  and  rb->rf.	The next 4 give the right-front output
		 in the same order, then left-back and right-back.

		 It is also possible to use the 16 numbers to expand or reduce
		 the channel count; just specify 0 for unused channels.

		 Finally, certain reduced combination of numbers can be speci-
		 fied for certain input/output channel combinations.


		 In Ch	Out Ch Num Mappings
		 _____	______ ___ _____________________________
		   2	  1	2   l->l, r->l
		   2	  2	1   adjust balance
		   4	  1	4   lf->l, rf->l, lb->l, rb-l
		   4	  2	2   lf->l&rf->r, lb->l&rb->r
		   4	  4	1   adjust balance
		   4	  4	2   front balance, back balance


       band [ -n ] center [ width ]
		 Apply a band-pass filter.  The frequency response drops loga-
		 rithmically around the center frequency.  The width gives the
		 slope of the drop.  The frequencies at	 center	 +  width  and
		 center	 -  width  will	 be half of their original amplitudes.
		 Band defaults to a mode oriented  to  pitched	signals,  i.e.
		 voice,	 singing,  or  instrumental music.  The -n (for noise)
		 option uses the alternate mode for un-pitched signals.	 Warn-
		 ing:  -n introduces a power-gain of about 11dB in the filter,
		 so beware of output clipping.	Band introduces noise  in  the
		 shape of the filter, i.e. peaking at the center frequency and
		 settling around it.  See filter for a	bandpass  effect  with
		 steeper shoulders.

       bandpass frequency bandwidth
		 Butterworth bandpass filter. Description coming soon!

       bandreject frequency bandwidth
		 Butterworth bandreject filter.	 Description coming soon!

       chorus gain-in gain-out delay decay speed depth

	      -s | -t [ delay decay speed depth -s | -t ... ]
		 Add   a   chorus   to	 a   sound   sample.   Each  quadtuple
		 delay/decay/speed/depth gives the delay in  milliseconds  and
		 the decay (relative to gain-in) with a modulation speed in Hz
		 using depth in milliseconds.  The modulation is either	 sinu-
		 soidal	 (-s)  or  triangular (-t).  Gain-out is the volume of
		 the output.

       compand attack1,decay1[,attack2,decay2...]

	       in-dB1,out-dB1[,in-dB2,out-dB2...]

	       [gain [initial-volume [delay ] ] ]
		 Compand (compress or expand) the dynamic range of  a  sample.
		 The  attack  and decay time specify the integration time over
		 which the absolute value of the input signal is integrated to
		 determine  its	 volume;  attacks refer to increases in volume
		 and decays refer to decreases.	 Where more than one  pair  of
		 attack/decay	parameters  are	 specified,  each  channel  is
		 treated separately and the number of pairs  must  agree  with
		 the number of input channels.	The second parameter is a list
		 of points on the compander’s transfer function	 specified  in
		 dB  relative  to  the maximum possible signal amplitude.  The
		 input values must be in a strictly increasing order  but  the
		 transfer  function  does not have to be monotonically rising.
		 The special value -inf may be used to indicate that the input
		 volume	 should	 be  associated	 output	 volume.   The	points
		 -inf,-inf and 0,0 are assumed; the latter may be  overridden,
		 but the former may not.

		 The  third  (optional) parameter is a post-processing gain in
		 dB which is applied after the compression  has	 taken	place;
		 the  fourth  (optional)  parameter is an initial volume to be
		 assumed for each channel when the effect starts.   This  per-
		 mits  the  user to supply a nominal level initially, so that,
		 for example, a very large gain is not applied to initial sig-
		 nal levels before the companding action has begun to operate:
		 it is quite probable that in such an event, the output	 would
		 be severely clipped while the compander gain properly adjusts
		 itself.

		 The fifth (optional) parameter is a delay  in	seconds.   The
		 input	signal	is analyzed immediately to control the compan-
		 der, but it  is  delayed  before  being  fed  to  the	volume
		 adjuster.   Specifying	 a  delay  approximately  equal to the
		 attack/decay times allows the compander to effectively	 oper-
		 ate in a "predictive" rather than a reactive mode.

       copy	 Copy  the input file to the output file.  This is the default
		 effect if both files have the same sampling rate.

       dcshift shift [ limitergain ]
		 DC Shift the audio data, with basic linear amplitude formula.
		 This  is  most	 useful	 if  your  audio  data tends to not be
		 centered around a value of 0.	Shifting it  back  will	 allow
		 you to get the most volume adjustments without clipping audio
		 data.
		 The first option is the dcshift  value.   It  is  a  floating
		 point number that indicates the amount to shift.
		 An  option  limtergain	 value	can  be specified as well.  It
		 should have a value much less then 1.0 and is	used  only  on
		 peaks to prevent clipping.

       deemph	 Apply	a  treble  attenuation	shelving  filter to samples in
		 audio cd format.  The frequency  response  of	pre-emphasized
		 recordings  is	 rectified.   The  filtering is defined in the
		 standard document ISO 908.

       earwax	 Makes sound easier to listen to on headphones.	  Adds	audio-
		 cues  to  samples in audio cd format so that when listened to
		 on headphones the stereo image is moved from inside your head
		 (standard for headphones) to outside and in front of the lis-
		 tener (standard for speakers). See
		 www.geocities.com/beinges for a full explanation.

       echo gain-in gain-out delay decay [ delay decay ... ]
		 Add echoing to a sound sample.	 Each delay/decay  part	 gives
		 the delay in milliseconds and the decay (relative to gain-in)
		 of that echo.	Gain-out is the volume of the output.

       echos gain-in gain-out delay decay [ delay decay ... ]
		 Add a sequence of echos to a sound sample.  Each  delay/decay
		 part  gives the delay in milliseconds and the decay (relative
		 to gain-in) of that echo.  Gain-out is the volume of the out-
		 put.

       fade [ type ] fade-in-length

	    [ stop-time [ fade-out-length ] ]
		 Add a fade effect to the beginning, end, or both of the audio
		 data.

		 For fade-ins, this starts from the first sample and ramps the
		 volume of the audio from 0 to full volume over fade-in-length
		 seconds.  Specify 0 seconds if no fade-in is wanted.

		 For fade-outs, the audio data will be truncated at the	 stop-
		 time and the volume will be ramped from full volume down to 0
		 starting at fade-out-length seconds before the stop-time.  No
		 fade-out is performed if these options are not specified.
		 All  times can be specified in either periods of time or sam-
		 ple  counts.	To  specify  time  periods  use	  the	format
		 hh:mm:ss.frac	format.	 To specify using sample counts, spec-
		 ify the number of samples and append the letter  ’s’  to  the
		 sample count (for example 8000s).
		 An optional type can be specified to change the type of enve-
		 lope.	Choices are q for quarter of a sinewave, h for half  a
		 sinewave,  t  for  linear slope, l for logarithmic, and p for
		 inverted parabola.  The default is a linear slope.

       filter [ low ]-[ high ] [ window-len [ beta ] ]
		 Apply a Sinc-windowed lowpass, highpass, or  bandpass	filter
		 of given window length to the signal.	low refers to the fre-
		 quency of the lower 6dB corner of the filter.	high refers to
		 the frequency of the upper 6dB corner of the filter.

		 A  lowpass  filter is obtained by leaving low unspecified, or
		 0.  A highpass filter is obtained by  leaving	high  unspeci-
		 fied,	or  0,	or  greater  than or equal to the Nyquist fre-
		 quency.

		 The window-len, if unspecified, defaults to 128.  Longer win-
		 dows  give  a	sharper cutoff, smaller windows a more gradual
		 cutoff.

		 The beta, if unspecified, defaults to	16.   This  selects  a
		 Kaiser window.	 You can select a Nuttall window by specifying
		 anything <= 2.0 here.	For  more  discussion  of  beta,  look
		 under the resample effect.


       flanger gain-in gain-out delay decay speed < -s | -t >
		 Add   a   flanger   to	  a   sound   sample.	 Each	triple
		 delay/decay/speed gives the delay  in	milliseconds  and  the
		 decay	(relative  to  gain-in) with a modulation speed in Hz.
		 The modulation is either sinodial (-s)	 or  triangular	 (-t).
		 Gain-out is the volume of the output.

       highp frequency
		 Apply	a  single  pole	 recursive high-pass filter.  The fre-
		 quency response drops logarithmically with I frequency in the
		 middle of the drop.  The slope of the filter is quite gentle.
		 See filter for a highpass effect with sharper cutoff.

       highpass frequency
		 Butterworth highpass filter.  Description coming soon!

       lowp frequency
		 Apply a single pole recursive low-pass filter.	 The frequency
		 response  drops  logarithmically with frequency in the middle
		 of the drop.  The slope of the filter is quite	 gentle.   See
		 filter for a lowpass effect with sharper cutoff.

       lowpass frequency
		 Butterworth lowpass filter.  Description coming soon!

       map	 Display  a  list of loops in a sample, and miscellaneous loop
		 info.

       mask	 Add "masking noise" to signal.	 This effect deliberately adds
		 white noise to a sound in order to mask quantization effects,
		 created by the process of  playing  a	sound  digitally.   It
		 tends	to  mask buzzing voices, for example.  It adds 1/2 bit
		 of noise to the sound file at the output bit depth.

       pan direction
		 Pan the sound of an audio file from one channel  to  another.
		 This  is done by changing the volume of the input channels so
		 that it fades out on one channel and fades-in on another.  If
		 the  number of input channels is different then the number of
		 output channels then this effect tries to intelligently  han-
		 dle  this.  For instance, if the input contains 1 channel and
		 the output contains 2 channels, then it will create the miss-
		 ing  channel  itself.	 The direction is a value from -1.0 to
		 1.0.  -1.0 represents far left and 1.0 represents far	right.
		 Numbers  in between will start the pan effect without totally
		 muting the opposite channel.

       phaser gain-in gain-out delay decay speed < -s | -t >
		 Add   a   phaser   to	 a   sound   sample.	Each	triple
		 delay/decay/speed  gives  the	delay  in milliseconds and the
		 decay (relative to gain-in) with a modulation	speed  in  Hz.
		 The  modulation  is  either sinodial (-s) or triangular (-t).
		 The decay should be less than 0.5 to avoid  feedback.	 Gain-
		 out is the volume of the output.

       pick [ -1 | -2 | -3 | -4 | -l | -r | -f | -b ]
		 Pick  a subset of channels to be copied into the output file.
		 This effect is just an alias of the "avg" effect but is  left
		 here for historical reasons.

       pitch shift [ width interpole fade ]
		 Change	 the  pitch  of file without affecting its duration by
		 cross-fading shifted samples.	shift is given in cents. Use a
		 positive value to shift to treble, negative value to shift to
		 bass.	Default shift is 0.  width of window is in ms. Default
		 width	is  20ms.  Try	30ms to lower pitch, and 10ms to raise
		 pitch.	 interpole option, can be "cubic" or "linear". Default
		 is  "cubic".  The fade option, can be "cos", "hamming", "lin-
		 ear" or "trapezoid".  Default is "cos".

       polyphase [ -w < nut / ham > ]

		 [  -width <  long  / short  / # > ]

		 [ -cutoff #  ]
		 Translate input sampling rate to  output  sampling  rate  via
		 polyphase  interpolation,  a  DSP  algorithm.	This method is
		 slow and uses lots of RAM, but gives much better results than
		 rate.

		 -w  <	nut / ham > : select either a Nuttal (~90 dB stopband)
		 or Hamming (~43 dB stopband) window.  Default is nut.

		 -width long / short / # : specify the (approximate) width  of
		 the  filter.	long  is  1024	samples; short is 128 samples.
		 Alternatively, an exact number can be used.  Default is long.
		 The  short  option  is	 not  recommended, as it produces poor
		 quality results.

		 -cutoff # : specify the filter cutoff frequency in  terms  of
		 fraction  of  frequency  bandwidth,  also know as the Nyquist
		 frequency.  Please see the resample effect for further infor-
		 mation on Nyquist frequency.  If upsampling, then this is the
		 fraction of the original signal that should go	 through.   If
		 downsampling,	this  is the fraction of the signal left after
		 downsampling.	Default is 0.95.   Remember  that  this	 is  a
		 float.


       rate	 Translate  input  sampling  rate  to output sampling rate via
		 linear interpolation to the Least Common Multiple of the  two
		 sampling  rates.  This is the default effect if the two files
		 have different sampling rates and  the	 preview  options  was
		 specified.  This is fast but noisy: the spectrum of the orig-
		 inal sound will be shifted  upwards  and  duplicated  faintly
		 when up-translating by a multiple.

		 Lerp-ing  is  acceptable  for cheap 8-bit sound hardware, but
		 for CD-quality sound you should instead use  either  resample
		 or  polyphase.	  If  you  are	wondering  which rate changing
		 effects to use, you will want to read a detailed analysis  of
		 all  of  them at http://eakaw2.et.tu-dresden.de/~wilde/resam-
		 ple/resample.html

       repeat count
		 Repeats the audio data count times.  Requires disk  space  to
		 store the data to be repeated.

       resample [ -qs | -q | -ql ] [ rolloff [ beta ] ]
		 Translate  input  sampling  rate  to output sampling rate via
		 simulated analog filtration.	This  method  is  slower  than
		 rate, but gives much better results.

		 By default, linear interpolation is used, with a window width
		 about 45 samples at the lower of the two rate.	 This gives an
		 accuracy  of  about 16 bits, but insufficient stopband rejec-
		 tion in the case that you want to have rolloff	 greater  than
		 about 0.80 of the Nyquist frequency.

		 The  -q*  options  will change the default values for rolloff
		 and beta as well as use  quadratic  interpolation  of	filter
		 coefficients, resulting in about 24 bits precision.  The -qs,
		 -q, or -ql options specify increased accuracy at the cost  of
		 lower execution speed.	 It is optional to specify rolloff and
		 beta parameters when using the -q* options.

		 Following is a table of the  reasonable  defaults  which  are
		 built-in to SoX:

		    Option  Window rolloff beta interpolation
		    ------  ------ ------- ---- -------------
		    (none)    45    0.80    16	   linear
		      -qs     45    0.80    16	  quadratic
		      -q      75    0.875   16	  quadratic
		      -ql    149    0.94    16	  quadratic
		    ------  ------ ------- ---- -------------

		 -qs, -q, or -ql use window lengths of 45, 75, or 149 samples,
		 respectively, at the lower  sample-rate  of  the  two	files.
		 This means progressively sharper stop-band rejection, at pro-
		 portionally slower execution times.

		 rolloff refers to the cut-off frequency of the low pass  fil-
		 ter  and  is  given in terms of the Nyquist frequency for the
		 lower sample rate.  rolloff  therefore	 should	 be  something
		 between  0.0 and 1.0, in practice 0.8-0.95.  The defaults are
		 indicated above.

		 The Nyquist frequency is equal to (sample rate /  2).	 Logi-
		 cally,	 this  is  because  the A/D converter needs at least 2
		 samples to detect 1 cycle at the Nyquist frequency.  Frequen-
		 cies  higher  then  the Nyquist will actually appear as lower
		 frequencies to the A/D	 converter  and	 is  called  aliasing.
		 Normally, A/D converts run the signal through a highpass fil-
		 ter first to avoid these problems.

		 Similar problems will happen in software  when	 reducing  the
		 sample	 rate  of  an  audio  file  (frequencies above the new
		 Nyquist frequency  can	 be  aliased  to  lower	 frequencies).
		 Therefore,  a	good resample effect will remove all frequency
		 information above the new Nyquist frequency.

		 The rolloff refers to how close to the Nyquist frequency this
		 cutoff	 is,  with  closer  being better.  When increasing the
		 sample rate of an audio file you would not expect to have any
		 frequencies  exist  that  are	past the original Nyquist fre-
		 quency.  Because of resampling properties, it	is  common  to
		 have aliasing data created that is above the old Nyquist fre-
		 quency.  In that case the rolloff refers to how close to  the
		 original Nyquist frequency to use a highpass filter to remove
		 this false data, with closer also being better.

		 The beta parameter determines the type of filter window used.
		 Any  value  greater than 2.0 is the beta for a Kaiser window.
		 Beta <= 2.0 selects a Nuttall window.	 If  unspecified,  the
		 default is a Kaiser window with beta 16.

		 In  the  case of Kaiser window (beta > 2.0), lower betas pro-
		 duce a somewhat faster transition from passband to  stopband,
		 at  the  cost	of  noticeable artifacts.  A beta of 16 is the
		 default, beta less than 10 is not recommended.	 If you want a
		 sharper  cutoff,  don’t  use  low beta’s, use a longer sample
		 window.  A Nuttall  window  is	 selected  by  specifying  any
		 ’beta’ <= 2, and the Nuttall window has somewhat steeper cut-
		 off than the default Kaiser window.  You  will	 probably  not
		 need  to  use	the beta parameter at all, unless you are just
		 curious about comparing the effects  of  Nuttall  vs.	Kaiser
		 windows.

		 This  is  the	default effect if the two files have different
		 sampling rates.  Default parameters are, as indicated	above,
		 Kaiser	 window	 of  length  45, rolloff 0.80, beta 16, linear
		 interpolation.

		 NOTE: -qs is only slightly  slower,  but  more	 accurate  for
		 16-bit or higher precision.

		 NOTE:	In  many  cases	 of  up-sampling,  no interpolation is
		 needed, as exact filter coefficients can  be  computed	 in  a
		 reasonable amount of space.  To be precise, this is done when

			    input_rate < output_rate
				       &&
		   output_rate/gcd(input_rate,output_rate) <= 511

       reverb gain-out reverbe-time delay [ delay ... ]
		 Add reverberation to a sound sample.  Each delay is given  in
		 milliseconds and its feedback is depending on the reverb-time
		 in milliseconds.  Each delay should be in the range  of  half
		 to  quarter  of reverb-time to get a realistic reverberation.
		 Gain-out is the volume of the output.

       reverse	 Reverse the sound sample completely.	Included  for  finding
		 Satanic subliminals.

       silence above_periods [ duration threshold[ d | % ]

	       [ below_periods duration

		 threshold[ d | % ]]
		 Removes  silence  from	 the beginning or end of a sound file.
		 Silence is anything below a specified threshold.
		 When trimming silence from the beginning of a sound file, you
		 specify  a  duration  of  audio that is above a given silence
		 threshold before audio data is processed.  You can also spec-
		 ify  the  count of periods of none silence you want to detect
		 before processing audio data.	Specify a period of 0  if  you
		 do not want to trim data from the front of the sound file.
		 When  optionally  trimming  silence  form  the end of a sound
		 file, you specify the duration of audio that must be below  a
		 given	threshold  before  stopping  to process audio data.  A
		 count of periods that occur below the threshold may  also  be
		 specified.   If  this	options are not specified then data is
		 not trimmed from the end of the audio file.
		 Duration counts may be in the format of time,	hh:mm:ss.frac,
		 or in the exact count of samples.
		 Threshold may be suffixed with d, or % to indicated the value
		 is in decibels or a percentage of max	value  of  the	sample
		 value.	 A value of ’0%’ will look for total silence.

       speed [ -c ] factor
		 Speed	up  or down the sound, as a magnetic tape with a speed
		 control.  It affects both pitch and time.  A  factor  of  1.0
		 means no change, and is the default.  2.0 doubles speed, thus
		 time length is cut by a half and pitch is one octave  higher.
		 0.5  halves  speed  thus time length doubles and pitch is one
		 octave lower.	If the optional -c parameter is used then  the
		 factor is specified in "cents".

       stat [ -s n ] [-rms ] [ -v ] [ -d ]
		 Do  a	statistical check on the input file, and print results
		 on the standard error file.  Audio data is passed  unmodified
		 from  input  to  output  file	unless	used along with the -e
		 option.

		 The "Volume Adjustment:" field in the	statistics  gives  you
		 the  argument	to the -v number which will make the sample as
		 loud as possible without clipping.

		 The option -v will print out the "Volume Adjustment:" field’s
		 value	only  and  return.  This could be of use in scripts to
		 auto convert the volume.

		 The -s n option is used to scale the input data  by  a	 given
		 factor.   The default value of n is the max value of a signed
		 long variable (0x7fffffff).   Internal	 effects  always  work
		 with  signed  long PCM data and so the value should relate to
		 this fact.

		 The -rms option will convert all  output  average  values  to
		 root mean square format.

		 There	is also an optional parameter -d that will print out a
		 hex dump of the sound file from the internal buffer  that  is
		 in  32-bit  signed  PCM  data.	 This is mainly only of use in
		 tracking down endian problems that creep in to SoX on	cross-
		 platform versions.


       stretch factor [window fade shift fading]
		 Time  stretch file by a given factor. Change duration without
		 affecting the pitch.  factor of  stretching:  >1.0  lengthen,
		 <1.0  shorten	duration.   window  size  is in ms. Default is
		 20ms. The fade option, can be "lin".  shift  ratio,  in  [0.0
		 1.0].	Default depends on stretch factor. 1.0 to shorten, 0.8
		 to lengthen.  The fading ratio, in [0.0 0.5]. The amount of a
		 fade’s default depends on factor and shift.

       swap [ 1 2 | 1 2 3 4 ]
		 Swap  channels in multi-channel sound files.  Optionally, you
		 may specify the channel order you would like the  output  in.
		 This  defaults	 to output channel 2 and then 1 for stereo and
		 2, 1, 4, 3 for quad-channels.	An interesting feature is that
		 you  may  duplicate  a	 given channel by overwriting another.
		 This is done by repeating an output channel  on  the  command
		 line.	 For  example,	swap 2 2 will overwrite channel 1 with
		 channel 2’s data; creating a stereo file with	both  channels
		 containing the same audio data.

       synth [ length ] type mix [ freq [ -freq2 ]

	     [ off ] [ ph ] [ p1 ] [ p2 ] [ p3 ]
		 The  synth  effect will generate various types of audio data.
		 Although this effect is used to generate audio data, an input
		 file  must  be specified.  The length of the input audio file
		 determines the length of the output audio file.
		 <length>  length  in  sec  or	hh:mm:ss.frac,	0=inputlength,
		 default=0
		 <type>	 is  sine,  square,  triangle, sawtooth, trapetz, exp,
		 whitenoise, pinknoise, brownnoise, default=sine
		 <mix> is create, mix, amod, default=create
		 <freq> frequency at beginning in Hz, not used	for noise..
		 <freq2>  frequency  at	 end  in  Hz,  not  used  for  noise..
		 <freq/2> can be given as %%n, where ’n’ is the number of half
		 notes in respect to A (440Hz)
		 <off> Bias (DC-offset)	 of signal in percent, default=0
		 <ph> phase shift 0..100 shift phase  0..2*Pi,	not  used  for
		 noise..
		 <p1>  square:	Ton/Toff,  triangle+trapetz: rising slope time
		 (0..100)
		 <p2> trapetz: ON time (0..100)
		 <p3> trapetz: falling slope position (0..100)

       trim start [ length ]
		 Trim can trim off unwanted audio data from the beginning  and
		 end  of  the  audio  file.  Audio samples are not sent to the
		 output stream until the start location is reached.
		 The optional length parameter tells the number of samples  to
		 output	 after	the  start  sample and is used to trim off the
		 back side of the audio data.  Using a	value  of  0  for  the
		 start parameter will allow trimming off the back side only.
		 Both  options can be specified using either an amount of time
		 and an exact count of samples.	  The  format  for  specifying
		 lengths  in  time  is hh:mm:ss.frac.  A start value of 1:30.5
		 will not start until 1 minute, thirty and  1/2	 seconds  into
		 the  audio  data.  The format for specifying sample counts is
		 the number of samples with the letter ’s’ appended to it.   A
		 value	of  8000s will wait until 8000 samples are read before
		 starting to process audio data.

       vibro speed  [ depth ]
		 Add the world-famous Fender Vibro-Champ  sound	 effect	 to  a
		 sound	sample by using a sine wave as the volume knob.	 Speed
		 gives the Hertz value of the wave.  This must	be  under  30.
		 Depth	gives  the  amount  the volume is cut into by the sine
		 wave, ranging 0.0 to 1.0 and defaulting to 0.5.

       vol gain [ type [ limitergain ] ]
		 The vol effect is much like the command line option  -v.   It
		 allows	 you  to adjust the volume of an input file and allows
		 you to specify	 the  adjustment  in  relation	to  amplitude,
		 power,	 or  dB.  If type is not specified then it defaults to
		 amplitude.
		 When type is amplitude then a linear change of the  amplitude
		 is  performed	based  on the gain.  Therefore, a value of 1.0
		 will keep the volume the same, 0.0 to < 1.0  will  cause  the
		 volume	 to decrease and values of > 1.0 will cause the volume
		 to increase.  Beware of clipping audio data when the gain  is
		 greater then 1.0.  A negative value performs the same adjust-
		 ment while also changing the phase.
		 When type is power then a value of 1.0 also means  no	change
		 in volume.
		 When  type  is	 dB  the amplitude is changed logarithmically.
		 0.0 is constant while +6 doubles the amplitude.
		 An optional limitergain value can be specified and should  be
		 a value much less then 1.0 (ie 0.05 or 0.02) and is used only
		 on peaks to prevent clipping.	Not specifying this  parameter
		 will  cause  no  limiter  to  be used.	 In verbose mode, this
		 effect will display the percentage of audio data that	needed
		 to be limited.

BUGS
       The  syntax  is	horrific.   Thats the breaks when trying to handle all
       things from the command line.

       Please report any bugs found in this version of SoX  to	Chris  Bagwell
       (cbagwell@users.sourceforge.net)

FILES
SEE ALSO
       play(1), rec(1), soxexam(1)

NOTICES
       The  version  of	 SoX  that  accompanies this manual page is support by
       Chris Bagwell (cbagwell@users.sourceforge.net).	Please refer any ques-
       tions  regarding it to this address.  You may obtain the latest version
       at the the web site http://sox.sourceforge.net/

AUTHOR
       Chris Bagwell (cbagwell@users.sourceforge.net).

       Updates by Anonymous



			       December 11, 2001			SoX(1)