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 26.173
22 ANSI-C code for the Adaptive Multi-Rate - Wideband (AMR-WB) speech codec
23 Available from http://www.3gpp.org
24
25 (C) 2007, 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: highpass_50Hz_at_12k8.cpp
35
36 Date: 05/08/2004
37
38 ------------------------------------------------------------------------------
39 REVISION HISTORY
40
41
42 Description:
43
44 ------------------------------------------------------------------------------
45 INPUT AND OUTPUT DEFINITIONS
46
47 int16 signal[], input signal / output is divided by 16
48 int16 lg, lenght of signal
49 int16 mem[] filter memory [6]
50
51
52 ------------------------------------------------------------------------------
53 FUNCTION DESCRIPTION
54
55 2nd order high pass filter with cut off frequency at 31 Hz.
56 Designed with cheby2 function in MATLAB.
57 Optimized for fixed-point to get the following frequency response:
58
59 frequency: 0Hz 14Hz 24Hz 31Hz 37Hz 41Hz 47Hz
60 dB loss: -infdB -15dB -6dB -3dB -1.5dB -1dB -0.5dB
61
62 Algorithm:
63
64 y[i] = b[0]*x[i] + b[1]*x[i-1] + b[2]*x[i-2]
65 + a[1]*y[i-1] + a[2]*y[i-2];
66
67 int16 b[3] = {4053, -8106, 4053}; in Q12
68 int16 a[3] = {8192, 16211, -8021}; in Q12
69
70 float --> b[3] = {0.989501953, -1.979003906, 0.989501953};
71 a[3] = {1.000000000, 1.978881836, -0.979125977};
72
73
74 ------------------------------------------------------------------------------
75 REQUIREMENTS
76
77
78 ------------------------------------------------------------------------------
79 REFERENCES
80
81 ------------------------------------------------------------------------------
82 PSEUDO-CODE
83
84 ------------------------------------------------------------------------------
85 */
86
87
88 /*----------------------------------------------------------------------------
89 ; INCLUDES
90 ----------------------------------------------------------------------------*/
91
92
93 #include "pv_amr_wb_type_defs.h"
94 #include "pvamrwbdecoder_basic_op.h"
95 #include "pvamrwb_math_op.h"
96 #include "pvamrwbdecoder_cnst.h"
97 #include "pvamrwbdecoder_acelp.h"
98
99
100 /*----------------------------------------------------------------------------
101 ; MACROS
102 ; Define module specific macros here
103 ----------------------------------------------------------------------------*/
104
105
106 /*----------------------------------------------------------------------------
107 ; DEFINES
108 ; Include all pre-processor statements here. Include conditional
109 ; compile variables also.
110 ----------------------------------------------------------------------------*/
111
112 /*----------------------------------------------------------------------------
113 ; LOCAL FUNCTION DEFINITIONS
114 ; Function Prototype declaration
115 ----------------------------------------------------------------------------*/
116
117 /*----------------------------------------------------------------------------
118 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS
119 ; Variable declaration - defined here and used outside this module
120 ----------------------------------------------------------------------------*/
121
122 /*----------------------------------------------------------------------------
123 ; EXTERNAL FUNCTION REFERENCES
124 ; Declare functions defined elsewhere and referenced in this module
125 ----------------------------------------------------------------------------*/
126
127 /*----------------------------------------------------------------------------
128 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
129 ; Declare variables used in this module but defined elsewhere
130 ----------------------------------------------------------------------------*/
131
132 /*----------------------------------------------------------------------------
133 ; FUNCTION CODE
134 ----------------------------------------------------------------------------*/
135
highpass_50Hz_at_12k8_init(int16 mem[])136 void highpass_50Hz_at_12k8_init(int16 mem[])
137 {
138 pv_memset((void *)mem, 0, 6*sizeof(*mem));
139 }
140
141 /*----------------------------------------------------------------------------
142 ; FUNCTION CODE
143 ----------------------------------------------------------------------------*/
144
highpass_50Hz_at_12k8(int16 signal[],int16 lg,int16 mem[])145 void highpass_50Hz_at_12k8(
146 int16 signal[], /* input/output signal */
147 int16 lg, /* lenght of signal */
148 int16 mem[] /* filter memory [6] */
149 )
150 {
151 int16 i, x2;
152 int16 y2_hi, y2_lo, y1_hi, y1_lo, x0, x1;
153 int32 L_tmp1;
154 int32 L_tmp2;
155 int16 *pt_sign = signal;
156
157 y2_hi = mem[0];
158 y2_lo = mem[1];
159 y1_hi = mem[2];
160 y1_lo = mem[3];
161 x0 = mem[4];
162 x1 = mem[5];
163
164
165 for (i = lg; i != 0; i--)
166 {
167
168 /* y[i] = b[0]*x[i] + b[1]*x[i-1] + b[0]*x[i-2] */
169 /* + a[0]*y[i-1] + a[1] * y[i-2]; */
170
171 L_tmp1 = fxp_mac_16by16(y1_lo, 16211, 8192L);
172 L_tmp1 = fxp_mac_16by16(y2_lo, -8021, L_tmp1);
173 L_tmp2 = fxp_mul_16by16(y1_hi, 32422);
174 L_tmp2 = fxp_mac_16by16(y2_hi, -16042, L_tmp2);
175
176 x2 = x1;
177 x1 = x0;
178 x0 = *pt_sign;
179 L_tmp2 = fxp_mac_16by16(x2, 8106, L_tmp2);
180 L_tmp2 = fxp_mac_16by16(x1, -16212, L_tmp2);
181 L_tmp2 = fxp_mac_16by16(x0, 8106, L_tmp2);
182
183
184 L_tmp1 = ((L_tmp1 >> 14) + L_tmp2) << 2;
185
186 y2_hi = y1_hi;
187 y2_lo = y1_lo;
188 y1_hi = (int16)(L_tmp1 >> 16);
189 y1_lo = (int16)((L_tmp1 - (y1_hi << 16)) >> 1);
190
191 /* coeff Q14 --> Q15 with saturation */
192 *(pt_sign++) = amr_wb_shl1_round(L_tmp1);
193
194 }
195
196
197 mem[0] = y2_hi;
198 mem[1] = y2_lo;
199 mem[2] = y1_hi;
200 mem[3] = y1_lo;
201 mem[4] = x0;
202 mem[5] = x1;
203
204 }
205
206