| /* |
| * 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. |
| */ |
| |
| /****************************************************************************************/ |
| /* */ |
| /* Includes */ |
| /* */ |
| /****************************************************************************************/ |
| |
| #include "AGC.h" |
| #include "ScalarArithmetic.h" |
| |
| |
| /****************************************************************************************/ |
| /* */ |
| /* Defines */ |
| /* */ |
| /****************************************************************************************/ |
| |
| #define VOL_TC_SHIFT 21 /* As a power of 2 */ |
| #define DECAY_SHIFT 10 /* As a power of 2 */ |
| |
| |
| /****************************************************************************************/ |
| /* */ |
| /* FUNCTION: AGC_MIX_VOL_2St1Mon_D32_WRA */ |
| /* */ |
| /* DESCRIPTION: */ |
| /* Apply AGC and mix signals */ |
| /* */ |
| /* */ |
| /* StSrc ------------------| */ |
| /* | */ |
| /* ______ _|_ ________ */ |
| /* | | | | | | */ |
| /* MonoSrc -->| AGC |---->| + |----->| Volume |------------------------------+---> */ |
| /* | Gain | |___| | Gain | | */ |
| /* |______| |________| | */ |
| /* /|\ __________ ________ | */ |
| /* | | | | | | */ |
| /* |-------------------------------| AGC Gain |<--| Peak |<--| */ |
| /* | Update | | Detect | */ |
| /* |__________| |________| */ |
| /* */ |
| /* */ |
| /* PARAMETERS: */ |
| /* pInstance Instance pointer */ |
| /* pStereoIn Stereo source */ |
| /* pMonoIn Mono band pass source */ |
| /* pStereoOut Stereo destination */ |
| /* */ |
| /* RETURNS: */ |
| /* Void */ |
| /* */ |
| /* NOTES: */ |
| /* */ |
| /****************************************************************************************/ |
| |
| void AGC_MIX_VOL_2St1Mon_D32_WRA(AGC_MIX_VOL_2St1Mon_D32_t *pInstance, /* Instance pointer */ |
| const LVM_INT32 *pStSrc, /* Stereo source */ |
| const LVM_INT32 *pMonoSrc, /* Mono source */ |
| LVM_INT32 *pDst, /* Stereo destination */ |
| LVM_UINT16 NumSamples) /* Number of samples */ |
| { |
| |
| /* |
| * General variables |
| */ |
| LVM_UINT16 i; /* Sample index */ |
| LVM_INT32 Left; /* Left sample */ |
| LVM_INT32 Right; /* Right sample */ |
| LVM_INT32 Mono; /* Mono sample */ |
| LVM_INT32 AbsPeak; /* Absolute peak signal */ |
| LVM_INT32 HighWord; /* High word in intermediate calculations */ |
| LVM_INT32 LowWord; /* Low word in intermediate calculations */ |
| LVM_INT16 AGC_Mult; /* Short AGC gain */ |
| LVM_INT16 Vol_Mult; /* Short volume */ |
| |
| |
| /* |
| * Instance control variables |
| */ |
| LVM_INT32 AGC_Gain = pInstance->AGC_Gain; /* Get the current AGC gain */ |
| LVM_INT32 AGC_MaxGain = pInstance->AGC_MaxGain; /* Get maximum AGC gain */ |
| LVM_INT16 AGC_GainShift = pInstance->AGC_GainShift; /* Get the AGC shift */ |
| LVM_INT16 AGC_Attack = pInstance->AGC_Attack; /* Attack scaler */ |
| LVM_INT16 AGC_Decay = pInstance->AGC_Decay; /* Decay scaler */ |
| LVM_INT32 AGC_Target = pInstance->AGC_Target; /* Get the target level */ |
| LVM_INT32 Vol_Current = pInstance->Volume; /* Actual volume setting */ |
| LVM_INT32 Vol_Target = pInstance->Target; /* Target volume setting */ |
| LVM_INT16 Vol_Shift = pInstance->VolumeShift; /* Volume shift scaling */ |
| LVM_INT16 Vol_TC = pInstance->VolumeTC; /* Time constant */ |
| |
| |
| /* |
| * Process on a sample by sample basis |
| */ |
| for (i=0;i<NumSamples;i++) /* For each sample */ |
| { |
| |
| /* |
| * Get the short scalers |
| */ |
| AGC_Mult = (LVM_INT16)(AGC_Gain >> 16); /* Get the short AGC gain */ |
| Vol_Mult = (LVM_INT16)(Vol_Current >> 16); /* Get the short volume gain */ |
| |
| |
| /* |
| * Get the input samples |
| */ |
| Left = *pStSrc++; /* Get the left sample */ |
| Right = *pStSrc++; /* Get the right sample */ |
| Mono = *pMonoSrc++; /* Get the mono sample */ |
| |
| |
| /* |
| * Apply the AGC gain to the mono input and mix with the stereo signal |
| */ |
| HighWord = (AGC_Mult * (Mono >> 16)); /* signed long (Mono) by unsigned short (AGC_Mult) multiply */ |
| LowWord = (AGC_Mult * (Mono & 0xffff)); |
| Mono = (HighWord + (LowWord >> 16)) << (AGC_GainShift); |
| Left += Mono; /* Mix in the mono signal */ |
| Right += Mono; |
| |
| |
| /* |
| * Apply the volume and write to the output stream |
| */ |
| HighWord = (Vol_Mult * (Left >> 16)); /* signed long (Left) by unsigned short (Vol_Mult) multiply */ |
| LowWord = (Vol_Mult * (Left & 0xffff)); |
| Left = (HighWord + (LowWord >> 16)) << (Vol_Shift); |
| HighWord = (Vol_Mult * (Right >> 16)); /* signed long (Right) by unsigned short (Vol_Mult) multiply */ |
| LowWord = (Vol_Mult * (Right & 0xffff)); |
| Right = (HighWord + (LowWord >> 16)) << (Vol_Shift); |
| *pDst++ = Left; /* Save the results */ |
| *pDst++ = Right; |
| |
| |
| /* |
| * Update the AGC gain |
| */ |
| AbsPeak = (Abs_32(Left)>Abs_32(Right)) ? Abs_32(Left) : Abs_32(Right); /* Get the absolute peak */ |
| if (AbsPeak > AGC_Target) |
| { |
| /* |
| * The signal is too large so decrease the gain |
| */ |
| HighWord = (AGC_Attack * (AGC_Gain >> 16)); /* signed long (AGC_Gain) by unsigned short (AGC_Attack) multiply */ |
| LowWord = (AGC_Attack * (AGC_Gain & 0xffff)); |
| AGC_Gain = (HighWord + (LowWord >> 16)) << 1; |
| } |
| else |
| { |
| /* |
| * The signal is too small so increase the gain |
| */ |
| if (AGC_Gain > AGC_MaxGain) |
| { |
| AGC_Gain -= (AGC_Decay << DECAY_SHIFT); |
| } |
| else |
| { |
| AGC_Gain += (AGC_Decay << DECAY_SHIFT); |
| } |
| } |
| |
| /* |
| * Update the gain |
| */ |
| Vol_Current += Vol_TC * ((Vol_Target - Vol_Current) >> VOL_TC_SHIFT); |
| } |
| |
| |
| /* |
| * Update the parameters |
| */ |
| pInstance->Volume = Vol_Current; /* Actual volume setting */ |
| pInstance->AGC_Gain = AGC_Gain; |
| |
| return; |
| } |
| |
