All files present in manifest contains silence, aborting next steps
**Describe the bug**

All files present in manifest contains silence, aborting next steps. 
When I run the diarization with an audio file which contains no speech, it terminates the program and throws an error

**Steps/Code to reproduce bug**

Run diarization on any audio wav file which contains no speech/audio


**Expected behavior**

Rather than program terminating, I would like a blank output and a blank rttm file.
Or how do I circumvent the "raise ValueError" in the script?
