Festival Speech Synthesis System: - Speech Resource Pages

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20.1.2 Generating LPC coefficients
LPC coefficients are generated using the `sig2fv' command. Two stages are required, generating the LPC
coefficients and generating the residual. The prototypical commands for these are
sig2fv wav/file001.wav -o lpc/file001.lpc -otype est -lpc_order 16 \
-coefs "lpc" -pm pm/file001.pm -preemph 0.95 -factor 3 \
-window_type hamming
sigfilter wav/file001.wav -o lpc/file001.res -otype nist \
-lpcfilter lpc/file001.lpc -inv_filter
For some databases you may need to normalize the power. Properly normalizing power is difficult but we provide a
simple function which may do the jobs acceptably. You should do this on the waveform before lpc analysis (and
ensure you also do the residual extraction on the normalized waveform rather than the original.
ch_wave -scaleN 0.5 wav/file001.wav -o file001.Nwav
This normalizes the power by maximizing the signal first then multiplying it by the given factor. If the database
waveforms are clean (i.e. no clicks) this can give reasonable results.
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20.2 Generating a diphone index
The diphone index consists of a short header following by an ascii list of each diphone, the file it comes from
followed by its start middle and end times in seconds. For most databases this files needs to be generated by some
database specific script.
An example header is
EST_File index
DataType ascii
NumEntries 2005
IndexName rab_diphone
EST_Header_End
The most notable part is the number of entries, which you should note can get out of sync with the actual number of
entries if you hand edit entries. I.e. if you add an entry and the system still can't find it check that the number of
entries is right.
The entries themselves may take on one of two forms, full entries or index entries. Full entries consist of a diphone
name, where the phones are separated by "-"; a file name which is used to index into the pitchmark, LPC and
waveform file; and the start, middle (change over point between phones) and end of the phone in the file in seconds
of the diphone. For example
r-uh edx_1001 0.225 0.261 0.320
r-e edx_1002 0.224 0.273 0.326
r-i edx_1003 0.240 0.280 0.321
r-o edx_1004 0.212 0.253 0.320
The second form of entry is an index entry which simply states that reference to that diphone should actually be made
to another. For example