sphinx_fe man page

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
-argfile
file (e.g. feat.params from an acoustic model) to read parameters from. This will override anything set in other command line arguments.
-blocksize
Number of samples to read at a time.
-build_outdirs
Create missing subdirectories in output directory
-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
-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
-npart
Number of parts to run in (supersedes -nskip and -runlen if non-zero)
-nskip
If a control file was specified, the number of utterances to skip at the head of the file
-o
cepstral output file
-ofmt
Format of output files - one of sphinx, htk, text.
-part
Index of the part to run (supersedes -nskip and -runlen if non-zero)
-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
If a control file was specified, the number of utterances to process, or -1 for all
-samprate
Sampling rate
-seed
Seed for random number generator; if less than zero, pick our own
-smoothspec
Write out cepstral-smoothed logspectral files
-sndfile
Use libsndfile to read input data
-spec2cep
Input is log spectral files, output is cepstral files
-sph2pipe
Input is NIST sphere (possibly with Shorten), use sph2pipe to convert
-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 (numbered from 1), or 0 to mix all channels
-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>

Referenced By

pocketsphinx_batch(1), pocketsphinx_continuous(1).

2007-08-27