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 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 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
