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Diffstat (limited to 'media/libeffects/lvm/lib/Common/src/LVC_Mixer_SetTarget.c')
| -rwxr-xr-x | media/libeffects/lvm/lib/Common/src/LVC_Mixer_SetTarget.c | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/media/libeffects/lvm/lib/Common/src/LVC_Mixer_SetTarget.c b/media/libeffects/lvm/lib/Common/src/LVC_Mixer_SetTarget.c new file mode 100755 index 0000000..4d3fe0c --- /dev/null +++ b/media/libeffects/lvm/lib/Common/src/LVC_Mixer_SetTarget.c @@ -0,0 +1,75 @@ +/* + * Copyright (C) 2004-2010 NXP Software + * Copyright (C) 2010 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/************************************************************************/ +/* */ +/* Project:: */ +/* $Author: beq07716 $*/ +/* $Revision: 1000 $*/ +/* $Date: 2010-06-28 13:08:20 +0200 (Mon, 28 Jun 2010) $*/ +/* */ +/************************************************************************/ + +#include "LVM_Types.h" +#include "LVM_Macros.h" +#include "LVC_Mixer_Private.h" + +/************************************************************************/ +/* FUNCTION: */ +/* LVMixer3_SetTarget */ +/* */ +/* DESCRIPTION: */ +/* This function updates the private instance parameters: Shift,Target,*/ +/* Current for a given Audio Stream based on new value of TargetGain */ +/* */ +/* This function caclulates the "Shift" required to provide the */ +/* integer part of TargetGain and fractional gain values "Target" and */ +/* "Current" based on maximum(TargetGain,CurrentGain) */ +/* E.g. CurrentGain=1.9 and TargetGain=2.5 then based on */ +/* MaxGain of 2.5, Shift = 2, Current=1.9/4=0.475, Target=2.5/4=0.625 */ +/* Therefore integer gain of 4 is provided by Left Shift of 2 and */ +/* fraction gain is provided through Current=0.475 and Target=0.625 */ +/* PARAMETERS: */ +/* pStream - ptr to Instance Parameter Structure LVMixer3_st */ +/* for an Audio Stream */ +/* TargetGain - TargetGain value in Q 16.15 format */ +/* */ +/* RETURNS: */ +/* void */ +/* */ +/************************************************************************/ + +void LVC_Mixer_SetTarget(LVMixer3_st *pStream, + LVM_INT32 TargetGain) +{ + LVM_INT32 Shift=0; + LVM_INT32 CurrentGain; + LVM_INT32 MaxGain=TargetGain; // MaxGain is in Q16.15 format + Mix_Private_st *pInstance=(Mix_Private_st *)pStream->PrivateParams; + CurrentGain=pInstance->Current>>(16-pInstance->Shift); // CurrentGain in Q16.15 format + if(CurrentGain>MaxGain) + MaxGain=CurrentGain; // MaxGain=max(CurrentGain,TargetGain) + + MaxGain=MaxGain>>15; // MaxGain in Q31.0 format i.e Integer part only + while(MaxGain>0){ // Update Shift required to provide integer gain + Shift++; + MaxGain=MaxGain>>1; + } + pInstance->Target=TargetGain<<(16-Shift); // Update fractional gain Target + pInstance->Current=CurrentGain<<(16-Shift); // Update fractional gain Current + pInstance->Shift=Shift; // Update Shift +} |