Generating Lattices

The phone-loop model can be used to create lattices by running:

utils/create_lattices_db.sh setup.sh parallel_opts keys_file model_dir output_dir

The lattices are created by first generating the posteriors of the GMMs of the phone-loop model and then by using this posteriors to HVite. Note that since we do not give any language model to HVite the best path from HTK lattices may differs from the best path computed with AMDTK (which uses either a unigram or a bigram language model over the units). Lattice generation parameters should be define in the setup.sh file:

 beam_thresh=0.0
 penalty=-1
 gscale=1
 conf_latt_dir="${root}/${model_type}/conf_lattices"

where:

• beam-thresh is the pruning threshold
• penalty is the inter model transition penalty (in the log domain)
• gscale is the grammar scale factor
• conf_latt_dir is the directory where should be store the HTK lattice configuration file