Provided by: speech-tools_2.1~release-6_amd64 
NAME
ch_wave — change/copy/combine waveform files
SYNOPSIS
ch_wave [-h] [-itype file type] [-n channels] [-f sample rate] [-ibo byte order] [-iswap]
[-istype sample type] [-c channel] [-start seconds] [-end seconds] [-from sample] [-to sample]
[-o output file] [-otype file type] [-F sample rate] [-obo byte order] [-oswap]
[-ostype sample type] [-scale factor] [-scaleN factor] [-lpfilter frequency] [-hpfilter freqency]
[-forder order] [-fafter] [-info] [-add] [-pc LONGEST | FIRST] [-key keylab file] [-divide]
[-ext file extension] [-extract file] input files ...
DESCRIPTION
ch_wave performs various operations on an input waveform file and writes it out to another file. Among
other things, it can extract subsections or individual channels, resample, rescale, mix down channels,
and perform simple filtering operations.
The following option flags are recognized:
-h Options help
-itype file type
Input file type (optional). If set to raw, this indicates that the input file does not have a
header. While this can be used to specify file types other than raw, this is rarely used for
other purposes as the file type of all the existing supported types can be determined
automatically from the file's header. If the input file is unheadered, files are assumed to
be shorts (16bit). Supported types are nist, est, esps, snd, riff, aiff, audlab, raw, ascii
-n channels Number of channels in an unheadered input file
-f sample rate
Sample rate in Hertz for an unheadered input file
-ibo byte order
Input byte order in an unheadered input file: possibliities are: MSB , LSB, native or
nonnative. Suns, HP, SGI Mips, M68000 are MSB (big endian) Intel, Alpha, DEC Mips, Vax are
LSB (little endian)
-iswap
Swap bytes. (For use on an unheadered input file)
-istype sample type
Sample type in an unheadered input file: short, alaw, mulaw, byte, ascii
-c channel
Select a single channel (starts from 0). Waveforms can have multiple channels. This option
extracts a single channel for progcessing and discards the rest.
-start seconds
Extract sub-wave starting at this time, specified in seconds
-end seconds
Extract sub-wave ending at this time, specified in seconds
-from sample
Extract sub-wave starting at this sample point
-to sample
Extract sub-wave ending at this sample point
-o output file
Output filename. If not specified output is to stdout.
-otype file type
Output file type, (optional). If no type is Specified the type of the input file is assumed.
Supported types are: nist, est, esps, snd, riff, aiff, audlab, raw, ascii
-F sample rate
Output sample rate in Hz. If this is different from the input sample rate, resampling will
occur
-obo byte order
Output byte order: MSB, LSB, native, or nonnative. Suns, HP, SGI Mips, M68000 are MSB (big
endian), Intel, Alpha, DEC Mips, Vax are LSB (little endian)
-oswap
Swap bytes when saving to output
-ostype sample type
Output sample type: short, alaw, mulaw, byte or ascii
-scale factor
Scaling factor. Increase or descrease the amplitude of the whole waveform by the factor given
(relative to 1.0)
-scaleN factor Scaling factor with normalization. The waveform is
scaled to its maximum level, after which it is scaled by the factor given (relative to 1.0)
-lpfilter frequency
Low pass filter, with cutoff frequency in Hz Filtering is performed by a FIR filter which is
built at run time. The order of the filter can be given by -forder. The default value is 199
-hpfilter freqency
High pass filter, with cutoff frequency in Hz Filtering is performed by a FIR filter which is
built at run time. The order of the filter can be given by -forder. The default value is 199.
-forder order
Order of FIR filter used for lpfilter and hpfilter. This must be ODD. Sensible values range
from 19 (quick but with a shallow rolloff) to 199 (slow but with a steep rolloff). The
default is 199.
-fafter
Do filtering after other operations such as resampling (default : filter before other
operations)
-info
Print information about file and header. This option gives useful information such as file
length, sampling rate, number of channels etc No output is produced
-add A new single channel waveform is created by adding the corresponding sample points of each
input waveform
-pc LONGEST | FIRST
Combine input waveforms to form a single multichannel waveform. The argument to this option
controls how long the new waveform should be. If the option is LONGEST, the output wave if
the length of the longest input wave and shorter waves are padded with zeros at the end. If
the option is FIRST, the length of the new waveform is the length of the first file on the
command line, and subsequent waves are padded or cut to this length
-key keylab file
Label file designating subsections, for use with -divide. The KEYLAB file is a label file
which specifies where chunks (such as individual sentences) in a waveform begin and end. See
section on wave extraction.
-divide
Divide a single input waveform into multiple output waveforms. Each output waveform is
extracted from the input waveform by using the KEYLAB file, which specifies the start and
stop times for each chunk. The output files are named according to the filename in the KEYLAB
file, with extension given by -ext. See section on wave extraction
-ext file extension
File extension for divided waveforms
-extract file
Used in conjunction with -key to extract a single section of waveform from the input
waveform. The argument is the name of a file given in the file column of the KEYLAB file.
EXAMPLES
BUGS
SEE ALSO
ch_track(1) ch_utt(1) na_record(1) na_play(1)
Edinburgh Speech Tools April 5, 2001 CH_WAVE(1)