Cepstral

What is Cepstral

Cepstral is a Text-to-Speech application. Using an Asterisk module allows you to integrate Asterisk with Cepstral. There are a number of modules available. Depending on what features and function that you would like to utilise.

Installing Cepstral

Download the voices that you would like to use. I have selected the default Allison voice as to integrate with the pre recorded Asterisk voices.

NOTE: I have selected the 8kHz voice which is standard for PBX systems. You may not want to select the 8kHz range as to get the best possible clarity. Typically you will not notice any difference but as the g722 codec (wideband) is coming into play you should notice better clarity if using the wideband codec and the desktop voices.

wget http://downloads.cepstral.com/cepstral/i386-linux/Cepstral_Allison-8kHz_i386-linux_5.1.0.tar.gz
tar xvzf Cepstral_Allison-8kHz_i386-linux_5.1.0.tar.gz
cd Cepstral_Allison-8kHz_i386-linux_5.1.0
./install.sh agree /opt/swift

Once you have extracted and installed Cepstral you need to make one more change.

echo /opt/swift/lib >> /etc/ld.so.conf.d/cepstral.conf
ldconfig

You can install as many voices as you like by repeating the first step above by selecting different Names. A complete list can be found here.

Swift

Swift is an Asterisk module that integrates with Cepstral. There are a number of different versions available. I will list two of them here.

mezzo

http://www.mezzo.net/asterisk/

This version will only work with Asterisk 1.4.x. I particularly like this version as you can install multiple voices in Cepstral and using this version of Swift you can select which voice you would like to utilise. Normally you have to select a voice in the configuration file and you can only use that voice.

Installing mezzo

wget http://www.mezzo.net/asterisk/app_swift-2.0rc1.tgz
tar xvzf app_swift-2.0rc1.tgz
cd app_swift-2.0rc1
make
make install

Now restart Asterisk or from the CLI

load app_swift.so

darrensessions

http://www.darrensessions.com/downloads/

This version works with Asterisk 1.4.x or 1.6.x. This version of Swift can not change voices like the mezzo version can but you can have digit timeouts and the expected number of digits which the mezzo version of Swift can not.

Installing darrensessions

Asterisk 1.4.x

wget http://www.darrensessions.com/pub/app_swift-1.4.2.tar.gz 
tar xvzf app_swift-1.4.2.tar.gz
cd app_swift-1.4.2
make
make install

Asterisk 1.6.0.x

wget http://www.darrensessions.com/pub/app_swift-1.6.2.tar.gz
tar xvzf app_swift-1.6.2.tar.gz
cd app_swift-1.6.2
make
make install

Loading Swift

Now restart Asterisk or from the CLI

load app_swift.so

Usage

To see how to use swift from the Asterisk CLI

core show application swift