Cepstral Support FAQ

If you do not find answers to your questions please feel free to open a support ticket.

Does Cepstral 6 conflict with other Asterisk modules?

Yes. There are two known conflicts: res_cepstral and app_festival. It is mandatory to remove both modules and restart Asterisk before installation. You may also need to kill the license server process.

res_cepstral was made by Digium and only works with Cepstral 5. Running Cepstral 6 and res_cepstral creates instability in the concurrent licensing. app_festival may yield a "Failed to set voice error" due to some low-level namespace conflicts.

One way to check if these modules are installed is to look in the asterisk/modules directory:

ls /usr/lib/asterisk/modules/*cepstral

ls /usr/lib/asterisk/modules/*fest

To move them to a backup location that will not interfere:

mv /usr/lib/asterisk/modules/res_cepstral.so /usr/lib/asterisk/modules/res_cepstral.so.bak

mv /usr/lib/asterisk/modules/app_festival.so /usr/lib/asterisk/modules/app_festival.so.bak

asterisk -rx "core restart now"

Why am I seeing the error app_swift.c:366 app_exec: Failed to set voice.

This is most likely a problem with the linking step of compiling app_swift. It only occurs with recent compilers gcc 4.6 on. If you run ldd app_swift.so, you will see it is missing the link to the swift libraries in /opt/swift/lib/. It doesn't know how to set the voice because it doesn't know how to execute the code to set the voice.


There doesn't seem to be a more elegant linker solution at the moment other than forcing the linker to load everything. This is done with the flag


Add that to SOLINK in app_swift's Makefile.

For example the entire Makefile for Cepstral 6 and asterisk 1.8 should be as below:

Full code here.

Then follow the steps again to reinstall the module in asterisk. make clean make make install asterisk -rx "restart now" This should remove this error.

How can I retrieve my license information?

If you have purchased voices or other licenses from Cepstral and need to retrieve your license information, you can make use of our Activation Key Recovery system.

To make use of the Recovery System, you need to have access to the email address you provided when you purchased your voices. To retrieve your license information, visit the Activation Key Recovery System and enter the email address you provided when you purchased your voices and other licenses, then our system will validate it against our records and mail your license information to you.

If you do not have access to the email account you used when you purchased, please contact us and we can update our system to reflect your current email address. Please provide as much information as you can regarding your purchase(s). Any of the following will be useful: your name, the email address you used when you purchased, and your order number(s). Please also provide your current email address.