1 /*
2 * Copyright (C) 2004-2010 NXP Software
3 * Copyright (C) 2010 The Android Open Source Project
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 #include "LVM_Types.h"
19 #include "LVM_Macros.h"
20 #include "LVC_Mixer_Private.h"
21
22
23 /************************************************************************/
24 /* FUNCTION: */
25 /* LVMixer3_VarSlope_SetTimeConstant */
26 /* */
27 /* DESCRIPTION: */
28 /* This function calculates the step change for fractional gain for a */
29 /* given time constant, sample rate and num channels */
30 /* Delta=(2147483647*4*1000)/(NumChannels*SampleRate*Tc_millisec) */
31 /* in Q 0.31 format */
32 /* */
33 /* PARAMETERS: */
34 /* pStream - ptr to Instance Parameter Structure LVMixer3_st for an*/
35 /* Audio Stream */
36 /* Tc_millisec - TimeConstant i.e time required in milli second to */
37 /* go from linear fractional gain of 0 to 0.99999999 */
38 /* Fs - LVM_Fs_en enumerator for Sampling Frequency */
39 /* NumChannels - Number of channels in Audio Stream 1=Mono, 2=Stereo */
40 /* */
41 /* UPDATES: */
42 /* Delta - the step change for fractional gain per 4 samples */
43 /* in Q0.31 format for a given Time Constant, */
44 /* Sample Rate and NumChannels */
45 /* RETURNS: */
46 /* void */
47 /************************************************************************/
48 #ifdef BUILD_FLOAT
LVC_Mixer_VarSlope_SetTimeConstant(LVMixer3_FLOAT_st * pStream,LVM_INT32 Tc_millisec,LVM_Fs_en Fs,LVM_INT16 NumChannels)49 void LVC_Mixer_VarSlope_SetTimeConstant( LVMixer3_FLOAT_st *pStream,
50 LVM_INT32 Tc_millisec,
51 LVM_Fs_en Fs,
52 LVM_INT16 NumChannels)
53 {
54 #ifdef HIGHER_FS
55 LVM_FLOAT DeltaTable[11] = {0.500000f,/*8000*/
56 0.362812f,/*11025*/
57 0.333333f,/*12000*/
58 0.250000f,/*16000*/
59 0.181406f,/*22050*/
60 0.166666f,/*24000*/
61 0.125000f,/*32000*/
62 0.090703f,/*44100*/
63 0.083333f,/*48000*/
64 0.041666f,/*96000*/
65 0.020833f};/*192000*/
66 #else
67 LVM_FLOAT DeltaTable[9] = {0.500000f,/*8000*/
68 0.362812f,/*11025*/
69 0.333333f,/*12000*/
70 0.250000f,/*16000*/
71 0.181406f,/*22050*/
72 0.166666f,/*24000*/
73 0.125000f,/*32000*/
74 0.090703f,/*44100*/
75 0.083333f};/*48000*/
76 #endif
77 LVM_FLOAT Tc_millisec_float;
78 Mix_Private_FLOAT_st *pInstance = (Mix_Private_FLOAT_st *)pStream->PrivateParams;
79 LVM_FLOAT Delta = DeltaTable[Fs];
80
81 LVM_FLOAT Current;
82 LVM_FLOAT Target;
83
84 Delta=Delta / (NumChannels);
85
86 /* Get gain values */
87 Current = pInstance->Current;
88 Target = pInstance->Target;
89
90 if (Current != Target)
91 {
92 Tc_millisec_float = (LVM_FLOAT)(Tc_millisec) / (Current - Target);
93 if (Tc_millisec_float < 0)
94 Tc_millisec_float = -Tc_millisec_float;
95
96 if(Tc_millisec == 0)
97 Delta = 1.000000f;
98 else
99 Delta = Delta / Tc_millisec_float;
100
101 if(Delta == 0)
102 Delta = 0.0000000005f; /* If Time Constant is so large that Delta is 0, \
103 assign minimum value to Delta */
104 }
105 else
106 {
107 Delta = 0.0000000005f; /* Minimum value for proper call-backs \
108 (setting it to zero has some problems, to be corrected) */
109 }
110
111 pInstance->Delta = Delta; // Delta=(2147483647*4*1000)/(NumChannels*SampleRate*Tc_millisec)
112 }
113 #else
LVC_Mixer_VarSlope_SetTimeConstant(LVMixer3_st * pStream,LVM_INT32 Tc_millisec,LVM_Fs_en Fs,LVM_INT16 NumChannels)114 void LVC_Mixer_VarSlope_SetTimeConstant( LVMixer3_st *pStream,
115 LVM_INT32 Tc_millisec,
116 LVM_Fs_en Fs,
117 LVM_INT16 NumChannels)
118 {
119 LVM_INT32 DeltaTable[9]={1073741824,
120 779132389,
121 715827882,
122 536870912,
123 389566194,
124 357913941,
125 268435456,
126 194783097,
127 178956971};
128 Mix_Private_st *pInstance=(Mix_Private_st *)pStream->PrivateParams;
129 LVM_INT32 Delta=DeltaTable[Fs];
130
131 LVM_INT32 Current;
132 LVM_INT32 Target;
133
134 Delta=Delta>>(NumChannels-1);
135
136 /* Get gain values */
137 Current = LVC_Mixer_GetCurrent( pStream );
138 Target = LVC_Mixer_GetTarget( pStream );
139
140 if (Current != Target)
141 {
142 Tc_millisec = Tc_millisec * 32767 / (Current - Target);
143 if (Tc_millisec<0) Tc_millisec = -Tc_millisec;
144
145 if(Tc_millisec==0)
146 Delta=0x7FFFFFFF;
147 else
148 Delta=Delta/Tc_millisec;
149
150 if(Delta==0)
151 Delta=1; // If Time Constant is so large that Delta is 0, assign minimum value to Delta
152 }
153 else
154 {
155 Delta =1; // Minimum value for proper call-backs (setting it to zero has some problems, to be corrected)
156 }
157
158
159 pInstance->Delta=Delta; // Delta=(2147483647*4*1000)/(NumChannels*SampleRate*Tc_millisec) in Q 0.31 format
160 }
161 #endif
162