asterisk/contrib

app_festival is an application that allows one to send text-to-speech commands

to a background festival server, and to obtain the resulting waveform which

gets sent down to the respective channel. app_festival also employs a waveform 

cache, so invariant text-to-speech strings ("Please press 1 for instructions") 

do not need to be dynamically generated all the time. 



You need : 



1) festival, patched to produce 8khz waveforms on output. Patch for Festival

1.4.2 RELEASE are included. The patch adds a new command to festival 

(asterisk_tts). 



It is possible to run Festival without patches in the source-code. Just

add this to your /etc/festival.scm or /usr/share/festival/festival/scm:



    (define (tts_textasterisk string mode)

    "(tts_textasterisk STRING MODE)

    Apply tts to STRING. This function is specifically designed for

    use in server mode so a single function call may synthesize the string.

    This function name may be added to the server safe functions."

    (let ((wholeutt (utt.synth (eval (list 'Utterance 'Text string)))))

    (utt.wave.resample wholeutt 8000)

    (utt.wave.rescale wholeutt 5)

    (utt.send.wave.client wholeutt)))



[See the comment with subject "Using Debian

 festival >= 1.4.3-15 (no recompiling needed!)" on

 http://www.voip-info.org/wiki-Asterisk+festival+installation for the

 original mentioning of it]



2) You may wish to obtain and install the asterisk-perl

module by James Golovich <james@gnuinter.net>, from 

either CPAN, or his site: http://asterisk.gnuinter.net,

as this contains a good example of how variable text

can be tts'd via asterisk, namely the examples/tts-*.agi

files there. It has been noted that the current expression

evaluation capabilities of asterisk are not best suited

for the generation and manipulation of text. AGI scripting

can be ideal for these sorts of needs. For simpler usage,

fixed, pre-recorded messages may be more amenable for your

purposes.



3) Before running asterisk, you have to run festival-server with a command 

like : 



/usr/local/festival/bin/festival --server > /dev/null 2>&1 &