formant.help

speech signal process tools

formant [-nn -on -pn -fn -in -wn -Wn -tn -ln -hn -Ps] <speech_file>

If the sampling frequency of the speech file is greater than 10kHz (or
nHz if the -f option is specified), "formant" downsamples the file to
10kHz (or nHz) and saves the results in a .ds file.  The signal is
then highpassed to remove DC and rumble and the result is saved in a
.hp file.  LPC poles are computed and saved in a .pole file.  The
fundamental frequency, VUV and rms energy are estimated and saved in a
.f0 file.  Finally, a dynamic programming algorithm estimates the best
global mapping of LPC poles to four formants and places the results in
a .fb file.  All of the files produced by "formant" have a SIG speech
header and all, except the .pole files, may be viewed as waveforms using the
"waves" program.  The .fb and .pole files may be overlaid on spectrograms
using waves.

Other options are:

  -on	n specifies the LPC order to use in the analysis [12]
  -nn	n specifies the number of formants to attempt tracking [4]
  -pn   n specifies the preemphasis constant (0.0 to 1.0) [0.7]
  -in	n specifies the frame interval in seconds [0.01]
  -wn	n specifies the window duration in sec. [0.049]
  -Wn   n specifies weighting type: 0=>rectangular; 1=>Hamming; 2->cos**4 [2]
  -tn   n = 0 implies autocorrelation LPC
	n = 1 means use Atal's stabilized covariance LPC (-w and -p ignored)
		(w forced to 0.025; p to exp(-1800 * pi * T))
	n = 2 means use standard covariance LPC [0]
	 (no weighting is applied if n > 0)
  -F	only compute F0; no .pole or .fb files are produced.
  -l	n specifies the low frequency limit for F0 tracking [50Hz]
  -h	n specifies the high frequency limit for F0 tracking [500Hz]
  -P	s is a F0 analysis param. file (see /usr/local/lib/formant/misc/param)

A SIG header may be added to the input speech file with

	addhead [-fn] <input_file>

  where n is the actual sampling frequency in Hz.  If not specified, n
        is assumed to be 10kHz.  <input_file>.d is the output file
	with the header prepended.