how does per-frame forced alignment likelihoods are computed

[Meenakshi S]

Hi, 

I have run the script steps/online/nnet2/align.sh and enabled the option --write-per-frame-acoustic-loglikes in nnet-align-compiled. As a result, I obtained frame-level scores. 

Question:

How does these scores are computed and their relation with posteriors?

Thanks!