1 /* /android/src/frameworks/base/libs/audioflinger/AudioShelvingFilter.cpp 2 ** 3 ** Copyright 2009, 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 "AudioShelvingFilter.h" 19 #include "AudioCommon.h" 20 #include "EffectsMath.h" 21 22 #include <new> 23 #include <assert.h> 24 #include <cutils/compiler.h> 25 26 namespace android { 27 // Format of the coefficient tables: 28 // kCoefTable[freq][gain][coef] 29 // freq - cutoff frequency, in octaves below Nyquist,from -10 to -6 in low 30 // shelf, -2 to 0 in high shelf. 31 // gain - gain, in millibel, starting at -9600, jumps of 1024, to 4736 millibel. 32 // coef - 0: b0 33 // 1: b1 34 // 2: b2 35 // 3: -a1 36 // 4: -a2 37 static const size_t kHiInDims[2] = {3, 15}; 38 static const audio_coef_t kHiCoefTable[3*15*5] = { 39 #include "AudioHighShelfFilterCoef.inl" 40 }; 41 static const size_t kLoInDims[2] = {5, 15}; 42 static const audio_coef_t kLoCoefTable[5*15*5] = { 43 #include "AudioLowShelfFilterCoef.inl" 44 }; 45 46 AudioCoefInterpolator AudioShelvingFilter::mHiCoefInterp(2, kHiInDims, 5, (const audio_coef_t*) kHiCoefTable); 47 AudioCoefInterpolator AudioShelvingFilter::mLoCoefInterp(2, kLoInDims, 5, (const audio_coef_t*) kLoCoefTable); 48 49 AudioShelvingFilter::AudioShelvingFilter(ShelfType type, int nChannels, 50 int sampleRate) 51 : mType(type), 52 mBiquad(nChannels, sampleRate) { 53 configure(nChannels, sampleRate); 54 } 55 56 void AudioShelvingFilter::configure(int nChannels, int sampleRate) { 57 mNiquistFreq = sampleRate * 500; 58 mFrequencyFactor = ((1ull) << 42) / mNiquistFreq; 59 mBiquad.configure(nChannels, sampleRate); 60 setFrequency(mNominalFrequency); 61 commit(true); 62 } 63 64 void AudioShelvingFilter::reset() { 65 setGain(0); 66 setFrequency(mType == kLowShelf ? 0 : mNiquistFreq); 67 commit(true); 68 } 69 70 void AudioShelvingFilter::setFrequency(uint32_t millihertz) { 71 mNominalFrequency = millihertz; 72 if (CC_UNLIKELY(millihertz > mNiquistFreq / 2)) { 73 millihertz = mNiquistFreq / 2; 74 } 75 uint32_t normFreq = static_cast<uint32_t>( 76 (static_cast<uint64_t>(millihertz) * mFrequencyFactor) >> 10); 77 uint32_t log2minFreq = (mType == kLowShelf ? (32-10) : (32-2)); 78 if (CC_LIKELY(normFreq > (1U << log2minFreq))) { 79 mFrequency = (Effects_log2(normFreq) - (log2minFreq << 15)) << (FREQ_PRECISION_BITS - 15); 80 } else { 81 mFrequency = 0; 82 } 83 } 84 85 void AudioShelvingFilter::setGain(int32_t millibel) { 86 mGain = millibel + 9600; 87 } 88 89 void AudioShelvingFilter::commit(bool immediate) { 90 audio_coef_t coefs[5]; 91 int intCoord[2] = { 92 mFrequency >> FREQ_PRECISION_BITS, 93 mGain >> GAIN_PRECISION_BITS 94 }; 95 uint32_t fracCoord[2] = { 96 mFrequency << (32 - FREQ_PRECISION_BITS), 97 static_cast<uint32_t>(mGain) << (32 - GAIN_PRECISION_BITS) 98 }; 99 if (mType == kHighShelf) { 100 mHiCoefInterp.getCoef(intCoord, fracCoord, coefs); 101 } else { 102 mLoCoefInterp.getCoef(intCoord, fracCoord, coefs); 103 } 104 mBiquad.setCoefs(coefs, immediate); 105 } 106 107 } 108