NAME

       sphinx_fe - Convert audio files to acoustic feature files

SYNOPSIS

       sphinx_fe [ options ]...

DESCRIPTION

       This program converts audio files (in either Microsoft WAV, NIST Sphere, or raw format) to
       acoustic feature files for input to batch-mode speech recognition.   The  resulting  files
       are also useful for various other things.  A list of options follows:

       -alpha Preemphasis parameter

       -blocksize
              Block  size,  used  to limit the number of samples used at a time when reading very
              large audio files

       -c     file for batch processing

       -cep2spec
              Input is cepstral files, output is log spectral files

       -di    directory, input file names are relative to this, if defined

       -dither
              Add 1/2-bit noise

       -do    directory, output files are relative to this

       -doublebw
              Use double bandwidth filters (same center freq)

       -ei    extension to be applied to all input files

       -eo    extension to be applied to all output files

       -example
              Shows example of how to use the tool

       -fbtype
              FB Type of mel_scale or log_linear

       -feat  SPHINX format - big endian

       -frate Frame rate

       -help  Shows the usage of the tool

       -i     audio input file

       -input_endian
              Endianness of input data, big or little, ignored if NIST or MS Wav

       -lifter
              Length of sin-curve for liftering, or 0 for no liftering.

       -logspec
              Write out logspectral files instead of cepstra

       -lowerf
              Lower edge of filters

       -mach_endian
              Endianness of machine, big or little

       -mswav Defines input format as Microsoft Wav (RIFF)

       -ncep  Number of cep coefficients

       -nchans
              Number of channels of data (interlaced samples assumed)

       -nfft  Size of FFT

       -nfilt Number of filter banks

       -nist  Defines input format as NIST sphere

       -nskip a control file was specified, the number of utterances to skip at the head  of  the
              file

       -o     cepstral output file

       -raw   Defines input format as raw binary data

       -remove_dc
              Remove DC offset from each frame

       -round_filters
              Round mel filter frequencies to DFT points

       -runlen
              a control file was specified, the number of utterances to process (see -nskip too)

       -samprate
              Sampling rate

       -seed  Seed for random number generator; if less than zero, pick our own

       -smoothspec
              Write out cepstral-smoothed logspectral files

       -spec2cep
              Input is log spectral files, output is cepstral files

       -transform
              Which type of transform to use to calculate cepstra (legacy, dct, or htk)

       -unit_area
              Normalize mel filters to unit area

       -upperf
              Upper edge of filters

       -verbose
              Show input filenames

       -warp_params
              defining the warping function

       -warp_type
              Warping function type (or shape)

       -whichchan
              Channel to process

       -wlen  Hamming window length

       Currently   the  only  kind  of  features  supported  are  MFCCs  (mel-frequency  cepstral
       coefficients).  There are numerous options which control  the  properties  of  the  output
       features.  It is VERY important that you document the specific set of flags used to create
       any given set of feature files, since this  information  is  NOT  recorded  in  the  files
       themselves,  and  any  mismatch  between  the  parameters  used  to  extract  features for
       recognition and those used to extract features for  training  will  cause  recognition  to
       fail.

AUTHOR

       Written  by  numerous people at CMU from 1994 onwards.  This manual page by David Huggins-
       Daines <dhuggins@cs.cmu.edu>

COPYRIGHT

       Copyright © 1994-2007 Carnegie Mellon University.  See the file COPYING included with this
       package for more information.

                                            2007-08-27                               SPHINX_FE(1)