I have installed Asterisk onto OS X (http://www.mezzo.net/asterisk/index.html) with app_swift included as well as a fully licensed Cepstral voice and am getting very choppy audio when using the Swift command. My swift.conf is below and seems to be the same as every example I have come across.


The output I get is very choppy, and unusable. Playing prerecorded audio files work fine.

Has anyone else came across this issue and found a way to fix it?

2 Answers 2


TTS is a very expensive process CPU wise. What kind of hardware are you running this on? I'd look at the output of top and see how loaded the CPU's are.

Choppy audio when doing TTS normally means that your hardware can't keep a real time flow of audio going.

Also if I remember correctly SWIFT caches generated audio, is it better the second time around?

Can you post the output of the top command while you are trying to use swift?

  • The machine isn't really working at all while running swift. I found something that seems to work for me, answer below.
    – John Duff
    Feb 16, 2010 at 20:10

I found a post taking about adjusting the framesize constant in app_swift and then recompiling and that seemed to work. I compiled app_swift from the github repository making the change mentioned and it's working a lot better.

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