| /* |
| * 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 */ |
| #define VOL_TC_FLOAT 2.0f /* As a power of 2 */ |
| #define DECAY_FAC_FLOAT 64.0f /* As a power of 2 */ |
| |
| /****************************************************************************************/ |
| /* */ |
| /* FUNCTION: AGC_MIX_VOL_Mc1Mon_D32_WRA */ |
| /* */ |
| /* DESCRIPTION: */ |
| /* Apply AGC and mix signals */ |
| /* */ |
| /* */ |
| /* McSrc ------------------| */ |
| /* | */ |
| /* ______ _|_ ________ */ |
| /* | | | | | | */ |
| /* MonoSrc -->| AGC |---->| + |----->| Volume |------------------------------+---> */ |
| /* | Gain | |___| | Gain | | */ |
| /* |______| |________| | */ |
| /* /|\ __________ ________ | */ |
| /* | | | | | | */ |
| /* |-------------------------------| AGC Gain |<--| Peak |<--| */ |
| /* | Update | | Detect | */ |
| /* |__________| |________| */ |
| /* */ |
| /* */ |
| /* PARAMETERS: */ |
| /* pInstance Instance pointer */ |
| /* pMcSrc Multichannel source */ |
| /* pMonoSrc Mono band pass source */ |
| /* pDst Multichannel destination */ |
| /* NrFrames Number of frames */ |
| /* NrChannels Number of channels */ |
| /* */ |
| /* RETURNS: */ |
| /* Void */ |
| /* */ |
| /* NOTES: */ |
| /* */ |
| /****************************************************************************************/ |
| void AGC_MIX_VOL_Mc1Mon_D32_WRA(AGC_MIX_VOL_2St1Mon_FLOAT_t* pInstance, const LVM_FLOAT* pMcSrc, |
| const LVM_FLOAT* pMonoSrc, LVM_FLOAT* pDst, LVM_UINT16 NrFrames, |
| LVM_UINT16 NrChannels) { |
| /* |
| * General variables |
| */ |
| LVM_UINT16 i, jj; /* Sample index */ |
| LVM_FLOAT SampleVal; /* Sample value */ |
| LVM_FLOAT Mono; /* Mono sample */ |
| LVM_FLOAT AbsPeak; /* Absolute peak signal */ |
| LVM_FLOAT AGC_Mult; /* Short AGC gain */ |
| LVM_FLOAT Vol_Mult; /* Short volume */ |
| |
| /* |
| * Instance control variables |
| */ |
| LVM_FLOAT AGC_Gain = pInstance->AGC_Gain; /* Get the current AGC gain */ |
| LVM_FLOAT AGC_MaxGain = pInstance->AGC_MaxGain; /* Get maximum AGC gain */ |
| LVM_FLOAT AGC_Attack = pInstance->AGC_Attack; /* Attack scaler */ |
| /* Decay scaler */ |
| LVM_FLOAT AGC_Decay = (pInstance->AGC_Decay * (1 << (DECAY_SHIFT))); |
| LVM_FLOAT AGC_Target = pInstance->AGC_Target; /* Get the target level */ |
| LVM_FLOAT Vol_Current = pInstance->Volume; /* Actual volume setting */ |
| LVM_FLOAT Vol_Target = pInstance->Target; /* Target volume setting */ |
| LVM_FLOAT Vol_TC = pInstance->VolumeTC; /* Time constant */ |
| |
| /* |
| * Process on a sample by sample basis |
| */ |
| for (i = 0; i < NrFrames; i++) /* For each frame */ |
| { |
| /* |
| * Get the scalers |
| */ |
| AGC_Mult = (LVM_FLOAT)(AGC_Gain); /* Get the AGC gain */ |
| Vol_Mult = (LVM_FLOAT)(Vol_Current); /* Get the volume gain */ |
| |
| AbsPeak = 0.0f; |
| /* |
| * Get the input samples |
| */ |
| for (jj = 0; jj < NrChannels; jj++) { |
| SampleVal = *pMcSrc++; /* Get the sample value of jj Channel*/ |
| Mono = *pMonoSrc; /* Get the mono sample */ |
| |
| /* |
| * Apply the AGC gain to the mono input and mix with the input signal |
| */ |
| SampleVal += (Mono * AGC_Mult); /* Mix in the mono signal */ |
| |
| /* |
| * Apply the volume and write to the output stream |
| */ |
| SampleVal = SampleVal * Vol_Mult; |
| |
| *pDst++ = LVM_Clamp(SampleVal); /* Save the results */ |
| |
| /* |
| * Update the AGC gain |
| */ |
| AbsPeak = Abs_Float(SampleVal) > AbsPeak ? Abs_Float(SampleVal) : AbsPeak; |
| } |
| if (AbsPeak > AGC_Target) { |
| /* |
| * The signal is too large so decrease the gain |
| */ |
| AGC_Gain = AGC_Gain * AGC_Attack; |
| } else { |
| /* |
| * The signal is too small so increase the gain |
| */ |
| if (AGC_Gain > AGC_MaxGain) { |
| AGC_Gain -= (AGC_Decay); |
| } else { |
| AGC_Gain += (AGC_Decay); |
| } |
| } |
| pMonoSrc++; |
| /* |
| * Update the gain |
| */ |
| Vol_Current += (Vol_Target - Vol_Current) * ((LVM_FLOAT)Vol_TC / VOL_TC_FLOAT); |
| } |
| |
| /* |
| * Update the parameters |
| */ |
| pInstance->Volume = Vol_Current; /* Actual volume setting */ |
| pInstance->AGC_Gain = AGC_Gain; |
| |
| return; |
| } |
