The first format consists of the header
NBestList1.0followed by one or more lines of the form
(score) w1 w2 w3 ...where score is a composite acoustic/language model score from the recognizer, on the bytelog scale. (A bytelog is a logarithm to base 1.0001, divided by 1024 and rounded to an integer.) This format is output by the SRI Decipher(TM) recognizer, by the ngram -nbest, and by nbest-lattice -write-nbest -decipher-nbest.
The second Decipher(TM) format is an extension of the first format that encodes word-level scores and time alignments. It is marked by a header of the form
NBestList2.0The hypotheses are in the format
(score) w1 ( st: st1 et: et1 g: g1 a: a1 ) w2 ...where words are followed by start and end times, language model and acoustic scores (bytelog-scaled), respectively. This format may also contain scores and time marks for sub-word units (phones and HMM states), in the same format as above, but with the w's denoting phone and state names. Sub-word units will have time marks that are contained in the duration of the preceding word units, and may thus be easily identified.
The third format understood by SRILM lists hypotheses in the format
ascore lscore nwords w1 w2 w3 ...where the first three columns contain the acoustic model log probability, the language model log probability, and the number of words in the hypothesis string, respectively. All scores are logarithms base 10. (This format must not be preceded by an ``NBestList'' header.) This format is output by the ngram -rescore and by nbest-lattice -write-nbest without the -decipher-nbest option.