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)