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)
