[Olympus developers 207]: N-best lists for PocketSphinx / Olympus

Blaise Thomson brmt2 at cam.ac.uk
Wed Mar 24 04:39:50 EDT 2010


Dear Olympus developers,

I am trying to get the Olympus LetsGo! system to provide an N-best list 
of speech recognition hypotheses. I found the -n_best switch which can 
be passed to the PocketSphinxEngine which is supposed to enable this but 
when I set the switch to anything other than 0 the system crashes 
immediately on any audio input. I remember you said that the system had 
been build to provide N-best lists so I was wondering if you could give 
any advice on why it is not working. Do you have a working N-best list 
system that you could send me to see how things are configured?

In trying to solve the problem I took a look at the PocketSphinxEngine 
source code and have noticed some possible memory access bugs which may 
be contributing to this. These were related to the way the 
iHypsGenerated variable was used. I've fixed these and can send them if 
you would like (I tried attaching them but the mailing list won't let 
me). The resulting code still crashes but at a later stage. After the 
fix, the log file generates a WARNING: "ngram_search.c", line 1000:. I 
don't know if this might be the cause of the problem. There is also a 
possibility that I simply have to add a configuration variable to 
PocketSphinx itself. At the moment I have only used the n_best switch on 
PocketSphinxEngine.

Please do let me know if you have any ideas of how to get this working 
or who else to contact.

Thanks for all you help,

Blaise




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