s3_align.c File Reference

Engine for Sphinx 3 aligner. More...

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <feat.h>
#include <strfuncs.h>
#include <s3types.h>
#include "mdef.h"
#include "tmat.h"
#include "dict.h"
#include "logs3.h"
#include "s3_align.h"

Classes
struct	pnode_s
struct	plink_s
struct	history_s
struct	snode_s
struct	slink_s

Macros
#define	ACTIVE_LIST_SIZE_INCR   16380

Typedefs
typedef struct pnode_s	pnode_t
typedef struct plink_s	plink_t
typedef struct history_s	history_t
typedef struct snode_s	snode_t
typedef struct slink_s	slink_t

Functions
int32	align_build_sent_hmm (char *wordstr, int insert_sil)
int32	align_destroy_sent_hmm (void)
void	align_sen_active (uint8 *senlist, int32 n_sen)
int32	align_start_utt (char *uttid)
int32	align_frame (int32 *senscr)
int32	align_end_utt (align_stseg_t **stseg_out, align_phseg_t **phseg_out, align_wdseg_t **wdseg_out)
int32	align_init (mdef_t *_mdef, tmat_t *_tmat, dict_t *_dict, cmd_ln_t *_config, logmath_t *_logmath)
void	align_free (void)

Detailed Description

Engine for Sphinx 3 aligner.

Macro Definition Documentation

ACTIVE_LIST_SIZE_INCR

#define ACTIVE_LIST_SIZE_INCR   16380

Typedef Documentation

history_t

typedef struct history_s history_t

Viterbi search history for each state at each time.

plink_t

typedef struct plink_s plink_t

A may have links (transitions) to several successor or predecessor nodes. They are captured by a list of the following plink_t type.

pnode_t

typedef struct pnode_s pnode_t

SOME ASSUMPTIONS

• All phones (ciphones and triphones) have same HMM topology with n_state states.
• Initial state = state 0; final state = state n_state-1.
• Final state is a non-emitting state with no arcs out of it.
• Some form of Bakis topology (ie, no cycles, except for self-transitions). Phone-level sentence HMM structures: pnode_t: nodes of phones forming sentence HMM. plink_t: a link between two pnode_t nodes. A phone node may have multiple successors and/or predecessors because of multiple alternative pronunciations for a word, as well as the presence of OPTIONAL filler words.

Assumptions:

• No cycles in phone level sentence HMM.

slink_t

typedef struct slink_s slink_t

snode_t

typedef struct snode_s snode_t

Head of list of all history nodes
State DAG structures similar to phone DAG structures.

Function Documentation

align_build_sent_hmm()

int32 align_build_sent_hmm	(	char *	wordstr,
		int	insert_sil
	)

Build a sentence HMM for the given transcription (wordstr). A two-level DAG is built: phone-level and state-level.

• <s> and </s> always added at the beginning and end of sentence to form an augmented transcription.
• Optional <sil> and noise words added between words in the augmented transcription. wordstr must contain only the transcript; no extraneous stuff such as utterance-id. Phone-level HMM structure has replicated nodes to allow for different left and right context CI phones; hence, each pnode corresponds to a unique triphone in the sentence HMM. Return 0 if successful, <0 if any error (eg, OOV word encountered).

Parameters

wordstr	In: Word transcript
insert_sil	In: Whether to insert silences/fillers

References slink_s::node.

align_destroy_sent_hmm()

int32 align_destroy_sent_hmm

(

void

)

align_end_utt()

int32 align_end_utt	(	align_stseg_t **	stseg_out,
		align_phseg_t **	phseg_out,
		align_wdseg_t **	wdseg_out
	)

All frames consumed. Trace back best Viterbi state sequence and dump it out.

Parameters

stseg_out	Out: list of state segmentation
phseg_out	Out: list of phone segmentation
wdseg_out	Out: list of word segmentation

align_frame()

int32 align_frame

(

int32 *

senscr

)

One frame of Viterbi time alignment.

Parameters

senscr

In: array of senone scores this frame

align_free()

void align_free

(

void

)

align_init()

int32 align_init	(	mdef_t *	_mdef,
		tmat_t *	_tmat,
		dict_t *	_dict,
		cmd_ln_t *	_config,
		logmath_t *	_logmath
	)

align_sen_active()

void align_sen_active	(	uint8 *	senlist,
		int32	n_sen
	)

Flag the active senones.

Parameters

senlist	Out: senlist[s] TRUE iff active in frame
n_sen	In: Size of senlist[] array

align_start_utt()

int32 align_start_utt

(

char *

uttid

)

Start Viterbi alignment using the sentence HMM previously built. Assumes that each utterance will only be aligned once; state member variables initialized during sentence HMM building.