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 /* FUNCTION: */
24 /* LVMixer3_Init */
25 /* */
26 /* DESCRIPTION: */
27 /* This intialization function intializes the private instance */
28 /* paramters for a given Audio Stream based on TargetGain and */
29 /* CurrentGain */
30 /* This function caclulates the "Shift" required to provide the */
31 /* integer part of TargetGain and fractional gain values "Target" and */
32 /* "Current" based on maximum(TargetGain,CurrentGain) */
33 /* E.g. CurrentGain=1.9 and TargetGain=2.5 then based on */
34 /* MaxGain of 2.5, Shift = 2, Current=1.9/4=0.475, Target=2.5/4=0.625 */
35 /* Therefore integer gain of 4 is provided by Left Shift of 2 and */
36 /* fraction gain is provided through Current=0.475 and Target=0.625 */
37 /* PARAMETERS: */
38 /* pStream - ptr to Instance Parameter Structure LVMixer3_st for an*/
39 /* Audio Stream */
40 /* TargetGain - TargetGain value in Q 16.15 format */
41 /* CurrentGain - CurrentGain value in Q 16.15 format */
42 /* */
43 /* RETURNS: */
44 /* void */
45 /* */
46 /************************************************************************/
47 #ifdef BUILD_FLOAT
LVC_Mixer_Init(LVMixer3_FLOAT_st * pStream,LVM_FLOAT TargetGain,LVM_FLOAT CurrentGain)48 void LVC_Mixer_Init( LVMixer3_FLOAT_st *pStream,
49 LVM_FLOAT TargetGain,
50 LVM_FLOAT CurrentGain)
51 {
52 LVM_FLOAT MaxGain = TargetGain;
53 Mix_Private_FLOAT_st *pInstance = (Mix_Private_FLOAT_st *)pStream->PrivateParams;
54 if(CurrentGain > MaxGain)
55 MaxGain = CurrentGain;
56 pInstance->Target = TargetGain; // Update fractional gain Target
57 pInstance->Current = CurrentGain; // Update fractional gain Current
58 }
59 #else
LVC_Mixer_Init(LVMixer3_st * pStream,LVM_INT32 TargetGain,LVM_INT32 CurrentGain)60 void LVC_Mixer_Init( LVMixer3_st *pStream,
61 LVM_INT32 TargetGain,
62 LVM_INT32 CurrentGain)
63 {
64 LVM_INT16 Shift=0;
65 LVM_INT32 MaxGain=TargetGain; // MaxGain is in Q16.15 format
66 Mix_Private_st *pInstance=(Mix_Private_st *)pStream->PrivateParams;
67 if(CurrentGain>MaxGain)
68 MaxGain=CurrentGain; // MaxGain=max(CurrentGain,TargetGain)
69
70 MaxGain=MaxGain>>15; // MaxGain in Q31.0 format i.e Integer part only
71 while(MaxGain>0){ // Update Shift required to provide integer gain
72 Shift++;
73 MaxGain=MaxGain>>1;
74 }
75 pInstance->Target=TargetGain<<(16-Shift); // Update fractional gain Target
76 pInstance->Current=CurrentGain<<(16-Shift); // Update fractional gain Current
77 pInstance->Shift=Shift; // Update Shift
78 }
79 #endif
80