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 25 #define LIKELY( exp ) (__builtin_expect( (exp) != 0, true )) 26 #define UNLIKELY( exp ) (__builtin_expect( (exp) != 0, false )) 27 28 namespace android { 29 // Format of the coefficient tables: 30 // kCoefTable[freq][gain][coef] 31 // freq - cutoff frequency, in octaves below Nyquist,from -10 to -6 in low 32 // shelf, -2 to 0 in high shelf. 33 // gain - gain, in millibel, starting at -9600, jumps of 1024, to 4736 millibel. 34 // coef - 0: b0 35 // 1: b1 36 // 2: b2 37 // 3: -a1 38 // 4: -a2 39 static const size_t kHiInDims[2] = {3, 15}; 40 static const audio_coef_t kHiCoefTable[3*15*5] = { 41 #include "AudioHighShelfFilterCoef.inl" 42 }; 43 static const size_t kLoInDims[2] = {5, 15}; 44 static const audio_coef_t kLoCoefTable[5*15*5] = { 45 #include "AudioLowShelfFilterCoef.inl" 46 }; 47 48 AudioCoefInterpolator AudioShelvingFilter::mHiCoefInterp(2, kHiInDims, 5, (const audio_coef_t*) kHiCoefTable); 49 AudioCoefInterpolator AudioShelvingFilter::mLoCoefInterp(2, kLoInDims, 5, (const audio_coef_t*) kLoCoefTable); 50 51 AudioShelvingFilter::AudioShelvingFilter(ShelfType type, int nChannels, 52 int sampleRate) 53 : mType(type), 54 mBiquad(nChannels, sampleRate) { 55 configure(nChannels, sampleRate); 56 } 57 58 void AudioShelvingFilter::configure(int nChannels, int sampleRate) { 59 mNiquistFreq = sampleRate * 500; 60 mFrequencyFactor = ((1ull) << 42) / mNiquistFreq; 61 mBiquad.configure(nChannels, sampleRate); 62 setFrequency(mNominalFrequency); 63 commit(true); 64 } 65 66 void AudioShelvingFilter::reset() { 67 setGain(0); 68 setFrequency(mType == kLowShelf ? 0 : mNiquistFreq); 69 commit(true); 70 } 71 72 void AudioShelvingFilter::setFrequency(uint32_t millihertz) { 73 mNominalFrequency = millihertz; 74 if (UNLIKELY(millihertz > mNiquistFreq / 2)) { 75 millihertz = mNiquistFreq / 2; 76 } 77 uint32_t normFreq = static_cast<uint32_t>( 78 (static_cast<uint64_t>(millihertz) * mFrequencyFactor) >> 10); 79 uint32_t log2minFreq = (mType == kLowShelf ? (32-10) : (32-2)); 80 if (LIKELY(normFreq > (1U << log2minFreq))) { 81 mFrequency = (Effects_log2(normFreq) - (log2minFreq << 15)) << (FREQ_PRECISION_BITS - 15); 82 } else { 83 mFrequency = 0; 84 } 85 } 86 87 void AudioShelvingFilter::setGain(int32_t millibel) { 88 mGain = millibel + 9600; 89 } 90 91 void AudioShelvingFilter::commit(bool immediate) { 92 audio_coef_t coefs[5]; 93 int intCoord[2] = { 94 mFrequency >> FREQ_PRECISION_BITS, 95 mGain >> GAIN_PRECISION_BITS 96 }; 97 uint32_t fracCoord[2] = { 98 mFrequency << (32 - FREQ_PRECISION_BITS), 99 static_cast<uint32_t>(mGain) << (32 - GAIN_PRECISION_BITS) 100 }; 101 if (mType == kHighShelf) { 102 mHiCoefInterp.getCoef(intCoord, fracCoord, coefs); 103 } else { 104 mLoCoefInterp.getCoef(intCoord, fracCoord, coefs); 105 } 106 mBiquad.setCoefs(coefs, immediate); 107 } 108 109 } 110