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)