Although never as good as extracting pitchmarks from an EGG signal,
we have had a fair amount of success in extracting pitchmarks from
the raw waveform. This area is somewhat a research area but in
this section we'll give some general pointers about how to get
pitchmarks form waveforms, or if not at least be able to tell
if you are getting reasonable pitchmarks from waveforms or not.
The basic program which we use for the extraction is pitchmark
which is part of the Speech Tools distribution. We include the
script bin/make_pm_wave (which is copied by ldom and diphone
setup process). The key line in the script is
$ESTDIR/bin/pitchmark tmp$$.wav -o pm/$fname.pm -otype est \
-min 0.005 -max 0.012 -fill -def 0.01 -wave_end \
-lx_lf 200 -lx_lo 51 -lx_hf 80 -lx_ho 51 -med_o 0
This program filters in incoming waveform (with a low and a high band
filter, then uses autocorellation to find the pitch mark peaks with the
min and max specified. Finally it fills in the unvoiced section with
the default pitchmarks.
For debugging purposes you should remove the -fill option
so you can see where it is finding pitchmarks. Next you should modify
the min and max values to fit the range of your speaker. The defaults
here (0.005 and 0.012) are for a male speaker in about the range 200 to
80 Hz. For a female you probably want values about 0.0033 and 0.7
(300Mhz to 140Hz).
Modify the script to your approximate needs, and run it on
a single file, then run the script that translates the pitchmark
file into a labeled file suitable for emulabel
bin/make_pm_wave wav/awb_0001.wav
bin/make_pm_pmlab pm/awb_0001.pm
You can the display the pitchmark with
emulabel etc/emu_pm awb_0001
This should should a number of pitchmarks over the voiced
sections of speech. If there are none, or very few it definitely
means the parameters are wrong. For example the above parameters
on this file
taataataa properly find pitchmarks in the three vowel
sections
It the high and low pass filter values
-lx_lf 200 -lx_hf 80
are in appropriate for the speakers pitch range you may get either
too many, or two few pitch marks. For example if we change the
200 to 60, we find only two pitch marks in the third vowel.
If we zoom in our first example we get the following
The pitch marks should be aligned to the largest (above zero)
peak in each pitch period. Here we can see there are too many pitchmarks
(effectively twice as many). The pitchmarks at 0.617, 0.628, 0.639 and
0.650 are extraneous. This means our pitch range is too wide. If
we rerun changing the min size, and the low frequency filter
$ESTDIR/bin/pitchmark tmp$$.wav -o pm/$fname.pm -otype est \
-min 0.007 -max 0.012 -fill -def 0.01 -wave_end \
-lx_lf 150 -lx_lo 51 -lx_hf 80 -lx_ho 51 -med_o 0
We get the following
Which is better but its now missing pitchmarks towards the end of
the vowel, at 0.634, 0.644 and 0.656. Giving more range
for the min (0.005) gives slight better results, but still we
get bad pitchmarks. The double pitch mark problem can be lessened by
not only changing the range but also the amount order of the high
and low pass filters (effectively allowing more smoothing). Thus
when secondary pitchmarks appear increasing the
-lx_lo parameter
often helps
$ESTDIR/bin/pitchmark tmp$$.wav -o pm/$fname.pm -otype est \
-min 0.005 -max 0.012 -fill -def 0.01 -wave_end \
-lx_lf 150 -lx_lo 91 -lx_hf 80 -lx_ho 51 -med_o 0
We get the following
This is satisfactory this file and probably for the whole databases of
that speaker. Though it is worth checking a few other files to get he best
results. Note the by increasing the order of the filer the pitchmark
creep forward (which is bad).
If you feel brave (or are desperate) you can actually edit the
pitchmarks yourself with emulabel. We have done this occasionally
especially when we find persistent synthesis errors (spikes etc).
You can convert a pm_lab file back into its pitchmark format with
bin/make_pm_pmlab pm_lab/*.lab
An post-processing step is provided that moves the predicted
pitchmarks to the nearest waveform peak. We find this useful for
both EGG extracted pitchmarks and waveform extracted ones. A
simple script is provided for this
bin/make_pm_fix pm/*.pm
If you pitchmarks are aligning to the largest troughs rather than peaks
your signal is upside down (or you are erroneously using -inv.
If you are using -inv, don't, if you are not, then invert
the signal itself with
for i in wav/*.wav
do
ch_wave -scale -1.0 $i -o $i
done
Note the above are quick heuristic hacks we have used when trying to
get pitchmarks out of wave signals. These require more work to offer a
more reliable solution, which we know exists. Extracting (fixed
frame) LPC coefficients and extracting a residual, then extracting
pitchmarks could give a more reliable solution but although all these
tools are available we have not experimented with that yet.
