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108 lines
3.5 KiB
108 lines
3.5 KiB
/* /android/src/frameworks/base/libs/audioflinger/AudioShelvingFilter.cpp
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**
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** Copyright 2009, The Android Open Source Project
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**
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** Licensed under the Apache License, Version 2.0 (the "License");
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** you may not use this file except in compliance with the License.
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** You may obtain a copy of the License at
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**
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** http://www.apache.org/licenses/LICENSE-2.0
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**
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** Unless required by applicable law or agreed to in writing, software
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** distributed under the License is distributed on an "AS IS" BASIS,
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** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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** See the License for the specific language governing permissions and
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** limitations under the License.
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*/
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#include "AudioShelvingFilter.h"
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#include "AudioCommon.h"
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#include "EffectsMath.h"
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#include <new>
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#include <assert.h>
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#include <cutils/compiler.h>
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namespace android {
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// Format of the coefficient tables:
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// kCoefTable[freq][gain][coef]
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// freq - cutoff frequency, in octaves below Nyquist,from -10 to -6 in low
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// shelf, -2 to 0 in high shelf.
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// gain - gain, in millibel, starting at -9600, jumps of 1024, to 4736 millibel.
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// coef - 0: b0
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// 1: b1
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// 2: b2
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// 3: -a1
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// 4: -a2
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static const size_t kHiInDims[2] = {3, 15};
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static const audio_coef_t kHiCoefTable[3*15*5] = {
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#include "AudioHighShelfFilterCoef.inl"
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};
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static const size_t kLoInDims[2] = {5, 15};
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static const audio_coef_t kLoCoefTable[5*15*5] = {
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#include "AudioLowShelfFilterCoef.inl"
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};
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AudioCoefInterpolator AudioShelvingFilter::mHiCoefInterp(2, kHiInDims, 5, (const audio_coef_t*) kHiCoefTable);
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AudioCoefInterpolator AudioShelvingFilter::mLoCoefInterp(2, kLoInDims, 5, (const audio_coef_t*) kLoCoefTable);
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AudioShelvingFilter::AudioShelvingFilter(ShelfType type, int nChannels,
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int sampleRate)
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: mType(type),
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mBiquad(nChannels, sampleRate) {
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configure(nChannels, sampleRate);
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}
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void AudioShelvingFilter::configure(int nChannels, int sampleRate) {
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mNiquistFreq = sampleRate * 500;
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mFrequencyFactor = ((1ull) << 42) / mNiquistFreq;
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mBiquad.configure(nChannels, sampleRate);
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setFrequency(mNominalFrequency);
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commit(true);
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}
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void AudioShelvingFilter::reset() {
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setGain(0);
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setFrequency(mType == kLowShelf ? 0 : mNiquistFreq);
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commit(true);
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}
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void AudioShelvingFilter::setFrequency(uint32_t millihertz) {
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mNominalFrequency = millihertz;
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if (CC_UNLIKELY(millihertz > mNiquistFreq / 2)) {
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millihertz = mNiquistFreq / 2;
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}
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uint32_t normFreq = static_cast<uint32_t>(
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(static_cast<uint64_t>(millihertz) * mFrequencyFactor) >> 10);
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uint32_t log2minFreq = (mType == kLowShelf ? (32-10) : (32-2));
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if (CC_LIKELY(normFreq > (1U << log2minFreq))) {
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mFrequency = (Effects_log2(normFreq) - (log2minFreq << 15)) << (FREQ_PRECISION_BITS - 15);
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} else {
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mFrequency = 0;
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}
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}
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void AudioShelvingFilter::setGain(int32_t millibel) {
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mGain = millibel + 9600;
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}
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void AudioShelvingFilter::commit(bool immediate) {
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audio_coef_t coefs[5];
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int intCoord[2] = {
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mFrequency >> FREQ_PRECISION_BITS,
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mGain >> GAIN_PRECISION_BITS
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};
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uint32_t fracCoord[2] = {
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mFrequency << (32 - FREQ_PRECISION_BITS),
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static_cast<uint32_t>(mGain) << (32 - GAIN_PRECISION_BITS)
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};
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if (mType == kHighShelf) {
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mHiCoefInterp.getCoef(intCoord, fracCoord, coefs);
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} else {
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mLoCoefInterp.getCoef(intCoord, fracCoord, coefs);
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}
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mBiquad.setCoefs(coefs, immediate);
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}
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}
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