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 frequency]
             [-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 frequency
                 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)