1 /* ------------------------------------------------------------------
2  * Copyright (C) 1998-2009 PacketVideo
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
13  * express or implied.
14  * See the License for the specific language governing permissions
15  * and limitations under the License.
16  * -------------------------------------------------------------------
17  */
18 /****************************************************************************************
19 Portions of this file are derived from the following 3GPP standard:
20 
21     3GPP TS 26.073
22     ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
23     Available from http://www.3gpp.org
24 
25 (C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
26 Permission to distribute, modify and use this file under the standard license
27 terms listed above has been obtained from the copyright holder.
28 ****************************************************************************************/
29 /*
30 ------------------------------------------------------------------------------
31 
32 
33 
34  Filename: /audio/gsm_amr/c/src/include/levinson.h
35 
36      Date: 01/29/2002
37 
38 ------------------------------------------------------------------------------
39  REVISION HISTORY
40  Description: 1. Modified "int" definition by Word16
41 
42  Description:  Replaced "int" and/or "char" with OSCL defined types.
43 
44  Description: Moved _cplusplus #ifdef after Include section.
45 
46  Description:
47 
48 ------------------------------------------------------------------------------
49  INCLUDE DESCRIPTION
50 
51       File             : lag_wind.h
52       Purpose          : Lag windowing of autocorrelations.
53 
54 ------------------------------------------------------------------------------
55 */
56 
57 #ifndef _LEVINSON_H_
58 #define _LEVINSON_H_
59 #define levinson_h "$Id $"
60 
61 /*----------------------------------------------------------------------------
62 ; INCLUDES
63 ----------------------------------------------------------------------------*/
64 #include "typedef.h"
65 #include "cnst.h"
66 
67 /*--------------------------------------------------------------------------*/
68 #ifdef __cplusplus
69 extern "C"
70 {
71 #endif
72 
73     /*----------------------------------------------------------------------------
74     ; MACROS
75     ; [Define module specific macros here]
76     ----------------------------------------------------------------------------*/
77 
78     /*----------------------------------------------------------------------------
79     ; DEFINES
80     ; [Include all pre-processor statements here.]
81     ----------------------------------------------------------------------------*/
82 
83     /*----------------------------------------------------------------------------
84     ; EXTERNAL VARIABLES REFERENCES
85     ; [Declare variables used in this module but defined elsewhere]
86     ----------------------------------------------------------------------------*/
87 
88     /*----------------------------------------------------------------------------
89     ; SIMPLE TYPEDEF'S
90     ----------------------------------------------------------------------------*/
91 
92     /*----------------------------------------------------------------------------
93     ; ENUMERATED TYPEDEF'S
94     ----------------------------------------------------------------------------*/
95 
96     /*----------------------------------------------------------------------------
97     ; STRUCTURES TYPEDEF'S
98     ----------------------------------------------------------------------------*/
99     typedef struct
100     {
101         Word16 old_A[M + 1];     /* Last A(z) for case of unstable filter */
102     } LevinsonState;
103 
104     /*----------------------------------------------------------------------------
105     ; GLOBAL FUNCTION DEFINITIONS
106     ; [List function prototypes here]
107     ----------------------------------------------------------------------------*/
108     Word16 Levinson_init(LevinsonState **st);
109     /* initialize one instance of the pre processing state.
110        Stores pointer to filter status struct in *st. This pointer has to
111        be passed to Levinson in each call.
112        returns 0 on success
113      */
114 
115     Word16 Levinson_reset(LevinsonState *st);
116     /* reset of pre processing state (i.e. set state memory to zero)
117        returns 0 on success
118      */
119     void Levinson_exit(LevinsonState **st);
120     /* de-initialize pre processing state (i.e. free status struct)
121        stores NULL in *st
122      */
123 
124     Word16 Levinson(
125         LevinsonState *st,
126         Word16 Rh[],       /* i : Rh[m+1] Vector of autocorrelations (msb) */
127         Word16 Rl[],       /* i : Rl[m+1] Vector of autocorrelations (lsb) */
128         Word16 A[],        /* o : A[m]    LPC coefficients  (m = 10)       */
129         Word16 rc[],        /* o : rc[4]   First 4 reflection coefficients  */
130         Flag   *pOverflow
131     );
132 
133 
134 
135 #ifdef __cplusplus
136 }
137 #endif
138 
139 #endif  /* _LEVINSON_H_ */
140 
141 
142 
143 
144