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 28namespace 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 39static const size_t kHiInDims[2] = {3, 15}; 40static const audio_coef_t kHiCoefTable[3*15*5] = { 41#include "AudioHighShelfFilterCoef.inl" 42}; 43static const size_t kLoInDims[2] = {5, 15}; 44static const audio_coef_t kLoCoefTable[5*15*5] = { 45#include "AudioLowShelfFilterCoef.inl" 46}; 47 48AudioCoefInterpolator AudioShelvingFilter::mHiCoefInterp(2, kHiInDims, 5, (const audio_coef_t*) kHiCoefTable); 49AudioCoefInterpolator AudioShelvingFilter::mLoCoefInterp(2, kLoInDims, 5, (const audio_coef_t*) kLoCoefTable); 50 51AudioShelvingFilter::AudioShelvingFilter(ShelfType type, int nChannels, 52 int sampleRate) 53 : mType(type), 54 mBiquad(nChannels, sampleRate) { 55 configure(nChannels, sampleRate); 56} 57 58void 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 66void AudioShelvingFilter::reset() { 67 setGain(0); 68 setFrequency(mType == kLowShelf ? 0 : mNiquistFreq); 69 commit(true); 70} 71 72void 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 87void AudioShelvingFilter::setGain(int32_t millibel) { 88 mGain = millibel + 9600; 89} 90 91void 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