SphinxBase 0.6
fe_warp.h
1/* ====================================================================
2 * Copyright (c) 2006 Carnegie Mellon University. All rights
3 * reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the
15 * distribution.
16 *
17 * This work was supported in part by funding from the Defense Advanced
18 * Research Projects Agency and the National Science Foundation of the
19 * United States of America, and the CMU Sphinx Speech Consortium.
20 *
21 * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND
22 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
23 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY
25 * NOR ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 *
33 * ====================================================================
34 *
35 */
36
37#ifndef FE_WARP_H
38#define FE_WARP_H
39
40#include "fe_internal.h"
41
42#ifdef __cplusplus
43extern "C" {
44#endif
45#if 0
46/* Fool Emacs. */
47}
48#endif
49
50#define FE_WARP_ID_INVERSE_LINEAR 0
51#define FE_WARP_ID_AFFINE 1
52#define FE_WARP_ID_PIECEWISE_LINEAR 2
53#define FE_WARP_ID_EIDE_GISH 3
54#define FE_WARP_ID_MAX 2
55#define FE_WARP_ID_NONE 0xffffffff
56
57typedef struct {
58 void (*set_parameters)(char const *param_str, float sampling_rate);
59 const char * (*doc)(void);
60 uint32 (*id)(void);
61 uint32 (*n_param)(void);
62 float (*warped_to_unwarped)(float nonlinear);
63 float (*unwarped_to_warped)(float linear);
64 void (*print)(const char *label);
66
67int fe_warp_set(melfb_t *mel, const char *id_name);
68
69uint32 fe_warp_id(melfb_t *mel);
70
71const char * fe_warp_doc(melfb_t *mel);
72
73void fe_warp_set_parameters(melfb_t *mel, char const *param_str, float sampling_rate);
74
75uint32 fe_warp_n_param(melfb_t *mel);
76
77float fe_warp_warped_to_unwarped(melfb_t *mel, float nonlinear);
78
79float fe_warp_unwarped_to_warped(melfb_t *mel, float linear);
80
81void fe_warp_print(melfb_t *mel, const char *label);
82
83#define FE_WARP_NO_SIZE 0xffffffff
84
85#ifdef __cplusplus
86}
87#endif
88
89
90#endif /* FE_WARP_H */
91
92/*
93 * Log record. Maintained by RCS.
94 *
95 * $Log: fe_warp.h,v $
96 * Revision 1.2 2006/02/17 00:31:34 egouvea
97 * Removed switch -melwarp. Changed the default for window length to
98 * 0.025625 from 0.256 (so that a window at 16kHz sampling rate has
99 * exactly 410 samples). Cleaned up include's. Replaced some E_FATAL()
100 * with E_WARN() and return.
101 *
102 * Revision 1.1 2006/02/16 00:18:26 egouvea
103 * Implemented flexible warping function. The user can specify at run
104 * time which of several shapes they want to use. Currently implemented
105 * are an affine function (y = ax + b), an inverse linear (y = a/x) and a
106 * piecewise linear (y = ax, up to a frequency F, and then it "breaks" so
107 * Nyquist frequency matches in both scales.
108 *
109 * Added two switches, -warp_type and -warp_params. The first specifies
110 * the type, which valid values:
111 *
112 * -inverse or inverse_linear
113 * -linear or affine
114 * -piecewise or piecewise_linear
115 *
116 * The inverse_linear is the same as implemented by EHT. The -mel_warp
117 * switch was kept for compatibility (maybe remove it in the
118 * future?). The code is compatible with EHT's changes: cepstra created
119 * from code after his changes should be the same as now. Scripts that
120 * worked with his changes should work now without changes. Tested a few
121 * cases, same results.
122 *
123 */
Base Struct to hold all structure for MFCC computation.
Definition fe_internal.h:89