| /* |
| * Copyright (C) 2013 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. |
| */ |
| |
| #define LOG_TAG "AudioResamplerDyn" |
| //#define LOG_NDEBUG 0 |
| |
| #include <malloc.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <dlfcn.h> |
| #include <math.h> |
| |
| #include <cutils/compiler.h> |
| #include <cutils/properties.h> |
| #include <utils/Debug.h> |
| #include <utils/Log.h> |
| |
| #include "AudioResamplerFirOps.h" // USE_NEON and USE_INLINE_ASSEMBLY defined here |
| #include "AudioResamplerFirProcess.h" |
| #include "AudioResamplerFirProcessNeon.h" |
| #include "AudioResamplerFirGen.h" // requires math.h |
| #include "AudioResamplerDyn.h" |
| |
| //#define DEBUG_RESAMPLER |
| |
| namespace android { |
| |
| // generate a unique resample type compile-time constant (constexpr) |
| #define RESAMPLETYPE(CHANNELS, LOCKED, STRIDE) \ |
| ((((CHANNELS)-1)&1) | !!(LOCKED)<<1 \ |
| | ((STRIDE)==8 ? 1 : (STRIDE)==16 ? 2 : 0)<<2) |
| |
| /* |
| * InBuffer is a type agnostic input buffer. |
| * |
| * Layout of the state buffer for halfNumCoefs=8. |
| * |
| * [rrrrrrppppppppnnnnnnnnrrrrrrrrrrrrrrrrrrr.... rrrrrrr] |
| * S I R |
| * |
| * S = mState |
| * I = mImpulse |
| * R = mRingFull |
| * p = past samples, convoluted with the (p)ositive side of sinc() |
| * n = future samples, convoluted with the (n)egative side of sinc() |
| * r = extra space for implementing the ring buffer |
| */ |
| |
| template<typename TC, typename TI, typename TO> |
| AudioResamplerDyn<TC, TI, TO>::InBuffer::InBuffer() |
| : mState(NULL), mImpulse(NULL), mRingFull(NULL), mStateCount(0) |
| { |
| } |
| |
| template<typename TC, typename TI, typename TO> |
| AudioResamplerDyn<TC, TI, TO>::InBuffer::~InBuffer() |
| { |
| init(); |
| } |
| |
| template<typename TC, typename TI, typename TO> |
| void AudioResamplerDyn<TC, TI, TO>::InBuffer::init() |
| { |
| free(mState); |
| mState = NULL; |
| mImpulse = NULL; |
| mRingFull = NULL; |
| mStateCount = 0; |
| } |
| |
| // resizes the state buffer to accommodate the appropriate filter length |
| template<typename TC, typename TI, typename TO> |
| void AudioResamplerDyn<TC, TI, TO>::InBuffer::resize(int CHANNELS, int halfNumCoefs) |
| { |
| // calculate desired state size |
| int stateCount = halfNumCoefs * CHANNELS * 2 * kStateSizeMultipleOfFilterLength; |
| |
| // check if buffer needs resizing |
| if (mState |
| && stateCount == mStateCount |
| && mRingFull-mState == mStateCount-halfNumCoefs*CHANNELS) { |
| return; |
| } |
| |
| // create new buffer |
| TI* state; |
| (void)posix_memalign(reinterpret_cast<void**>(&state), 32, stateCount*sizeof(*state)); |
| memset(state, 0, stateCount*sizeof(*state)); |
| |
| // attempt to preserve state |
| if (mState) { |
| TI* srcLo = mImpulse - halfNumCoefs*CHANNELS; |
| TI* srcHi = mImpulse + halfNumCoefs*CHANNELS; |
| TI* dst = state; |
| |
| if (srcLo < mState) { |
| dst += mState-srcLo; |
| srcLo = mState; |
| } |
| if (srcHi > mState + mStateCount) { |
| srcHi = mState + mStateCount; |
| } |
| memcpy(dst, srcLo, (srcHi - srcLo) * sizeof(*srcLo)); |
| free(mState); |
| } |
| |
| // set class member vars |
| mState = state; |
| mStateCount = stateCount; |
| mImpulse = state + halfNumCoefs*CHANNELS; // actually one sample greater than needed |
| mRingFull = state + mStateCount - halfNumCoefs*CHANNELS; |
| } |
| |
| // copy in the input data into the head (impulse+halfNumCoefs) of the buffer. |
| template<typename TC, typename TI, typename TO> |
| template<int CHANNELS> |
| void AudioResamplerDyn<TC, TI, TO>::InBuffer::readAgain(TI*& impulse, const int halfNumCoefs, |
| const TI* const in, const size_t inputIndex) |
| { |
| TI* head = impulse + halfNumCoefs*CHANNELS; |
| for (size_t i=0 ; i<CHANNELS ; i++) { |
| head[i] = in[inputIndex*CHANNELS + i]; |
| } |
| } |
| |
| // advance the impulse pointer, and load in data into the head (impulse+halfNumCoefs) |
| template<typename TC, typename TI, typename TO> |
| template<int CHANNELS> |
| void AudioResamplerDyn<TC, TI, TO>::InBuffer::readAdvance(TI*& impulse, const int halfNumCoefs, |
| const TI* const in, const size_t inputIndex) |
| { |
| impulse += CHANNELS; |
| |
| if (CC_UNLIKELY(impulse >= mRingFull)) { |
| const size_t shiftDown = mRingFull - mState - halfNumCoefs*CHANNELS; |
| memcpy(mState, mState+shiftDown, halfNumCoefs*CHANNELS*2*sizeof(TI)); |
| impulse -= shiftDown; |
| } |
| readAgain<CHANNELS>(impulse, halfNumCoefs, in, inputIndex); |
| } |
| |
| template<typename TC, typename TI, typename TO> |
| void AudioResamplerDyn<TC, TI, TO>::Constants::set( |
| int L, int halfNumCoefs, int inSampleRate, int outSampleRate) |
| { |
| int bits = 0; |
| int lscale = inSampleRate/outSampleRate < 2 ? L - 1 : |
| static_cast<int>(static_cast<uint64_t>(L)*inSampleRate/outSampleRate); |
| for (int i=lscale; i; ++bits, i>>=1) |
| ; |
| mL = L; |
| mShift = kNumPhaseBits - bits; |
| mHalfNumCoefs = halfNumCoefs; |
| } |
| |
| template<typename TC, typename TI, typename TO> |
| AudioResamplerDyn<TC, TI, TO>::AudioResamplerDyn(int bitDepth, |
| int inChannelCount, int32_t sampleRate, src_quality quality) |
| : AudioResampler(bitDepth, inChannelCount, sampleRate, quality), |
| mResampleFunc(0), mFilterSampleRate(0), mFilterQuality(DEFAULT_QUALITY), |
| mCoefBuffer(NULL) |
| { |
| mVolumeSimd[0] = mVolumeSimd[1] = 0; |
| // The AudioResampler base class assumes we are always ready for 1:1 resampling. |
| // We reset mInSampleRate to 0, so setSampleRate() will calculate filters for |
| // setSampleRate() for 1:1. (May be removed if precalculated filters are used.) |
| mInSampleRate = 0; |
| mConstants.set(128, 8, mSampleRate, mSampleRate); // TODO: set better |
| } |
| |
| template<typename TC, typename TI, typename TO> |
| AudioResamplerDyn<TC, TI, TO>::~AudioResamplerDyn() |
| { |
| free(mCoefBuffer); |
| } |
| |
| template<typename TC, typename TI, typename TO> |
| void AudioResamplerDyn<TC, TI, TO>::init() |
| { |
| mFilterSampleRate = 0; // always trigger new filter generation |
| mInBuffer.init(); |
| } |
| |
| template<typename TC, typename TI, typename TO> |
| void AudioResamplerDyn<TC, TI, TO>::setVolume(int16_t left, int16_t right) |
| { |
| AudioResampler::setVolume(left, right); |
| // volume is applied on the output type. |
| if (is_same<TO, float>::value || is_same<TO, double>::value) { |
| const TO scale = 1. / (1UL << 12); |
| mVolumeSimd[0] = static_cast<TO>(left) * scale; |
| mVolumeSimd[1] = static_cast<TO>(right) * scale; |
| } else { |
| mVolumeSimd[0] = static_cast<int32_t>(left) << 16; |
| mVolumeSimd[1] = static_cast<int32_t>(right) << 16; |
| } |
| } |
| |
| template<typename T> T max(T a, T b) {return a > b ? a : b;} |
| |
| template<typename T> T absdiff(T a, T b) {return a > b ? a - b : b - a;} |
| |
| template<typename TC, typename TI, typename TO> |
| void AudioResamplerDyn<TC, TI, TO>::createKaiserFir(Constants &c, |
| double stopBandAtten, int inSampleRate, int outSampleRate, double tbwCheat) |
| { |
| TC* buf; |
| static const double atten = 0.9998; // to avoid ripple overflow |
| double fcr; |
| double tbw = firKaiserTbw(c.mHalfNumCoefs, stopBandAtten); |
| |
| (void)posix_memalign(reinterpret_cast<void**>(&buf), 32, (c.mL+1)*c.mHalfNumCoefs*sizeof(TC)); |
| if (inSampleRate < outSampleRate) { // upsample |
| fcr = max(0.5*tbwCheat - tbw/2, tbw/2); |
| } else { // downsample |
| fcr = max(0.5*tbwCheat*outSampleRate/inSampleRate - tbw/2, tbw/2); |
| } |
| // create and set filter |
| firKaiserGen(buf, c.mL, c.mHalfNumCoefs, stopBandAtten, fcr, atten); |
| c.mFirCoefs = buf; |
| if (mCoefBuffer) { |
| free(mCoefBuffer); |
| } |
| mCoefBuffer = buf; |
| #ifdef DEBUG_RESAMPLER |
| // print basic filter stats |
| printf("L:%d hnc:%d stopBandAtten:%lf fcr:%lf atten:%lf tbw:%lf\n", |
| c.mL, c.mHalfNumCoefs, stopBandAtten, fcr, atten, tbw); |
| // test the filter and report results |
| double fp = (fcr - tbw/2)/c.mL; |
| double fs = (fcr + tbw/2)/c.mL; |
| double passMin, passMax, passRipple; |
| double stopMax, stopRipple; |
| testFir(buf, c.mL, c.mHalfNumCoefs, fp, fs, /*passSteps*/ 1000, /*stopSteps*/ 100000, |
| passMin, passMax, passRipple, stopMax, stopRipple); |
| printf("passband(%lf, %lf): %.8lf %.8lf %.8lf\n", 0., fp, passMin, passMax, passRipple); |
| printf("stopband(%lf, %lf): %.8lf %.3lf\n", fs, 0.5, stopMax, stopRipple); |
| #endif |
| } |
| |
| // recursive gcd. Using objdump, it appears the tail recursion is converted to a while loop. |
| static int gcd(int n, int m) |
| { |
| if (m == 0) { |
| return n; |
| } |
| return gcd(m, n % m); |
| } |
| |
| static bool isClose(int32_t newSampleRate, int32_t prevSampleRate, |
| int32_t filterSampleRate, int32_t outSampleRate) |
| { |
| |
| // different upsampling ratios do not need a filter change. |
| if (filterSampleRate != 0 |
| && filterSampleRate < outSampleRate |
| && newSampleRate < outSampleRate) |
| return true; |
| |
| // check design criteria again if downsampling is detected. |
| int pdiff = absdiff(newSampleRate, prevSampleRate); |
| int adiff = absdiff(newSampleRate, filterSampleRate); |
| |
| // allow up to 6% relative change increments. |
| // allow up to 12% absolute change increments (from filter design) |
| return pdiff < prevSampleRate>>4 && adiff < filterSampleRate>>3; |
| } |
| |
| template<typename TC, typename TI, typename TO> |
| void AudioResamplerDyn<TC, TI, TO>::setSampleRate(int32_t inSampleRate) |
| { |
| if (mInSampleRate == inSampleRate) { |
| return; |
| } |
| int32_t oldSampleRate = mInSampleRate; |
| int32_t oldHalfNumCoefs = mConstants.mHalfNumCoefs; |
| uint32_t oldPhaseWrapLimit = mConstants.mL << mConstants.mShift; |
| bool useS32 = false; |
| |
| mInSampleRate = inSampleRate; |
| |
| // TODO: Add precalculated Equiripple filters |
| |
| if (mFilterQuality != getQuality() || |
| !isClose(inSampleRate, oldSampleRate, mFilterSampleRate, mSampleRate)) { |
| mFilterSampleRate = inSampleRate; |
| mFilterQuality = getQuality(); |
| |
| // Begin Kaiser Filter computation |
| // |
| // The quantization floor for S16 is about 96db - 10*log_10(#length) + 3dB. |
| // Keep the stop band attenuation no greater than 84-85dB for 32 length S16 filters |
| // |
| // For s32 we keep the stop band attenuation at the same as 16b resolution, about |
| // 96-98dB |
| // |
| |
| double stopBandAtten; |
| double tbwCheat = 1.; // how much we "cheat" into aliasing |
| int halfLength; |
| if (mFilterQuality == DYN_HIGH_QUALITY) { |
| // 32b coefficients, 64 length |
| useS32 = true; |
| stopBandAtten = 98.; |
| if (inSampleRate >= mSampleRate * 4) { |
| halfLength = 48; |
| } else if (inSampleRate >= mSampleRate * 2) { |
| halfLength = 40; |
| } else { |
| halfLength = 32; |
| } |
| } else if (mFilterQuality == DYN_LOW_QUALITY) { |
| // 16b coefficients, 16-32 length |
| useS32 = false; |
| stopBandAtten = 80.; |
| if (inSampleRate >= mSampleRate * 4) { |
| halfLength = 24; |
| } else if (inSampleRate >= mSampleRate * 2) { |
| halfLength = 16; |
| } else { |
| halfLength = 8; |
| } |
| if (inSampleRate <= mSampleRate) { |
| tbwCheat = 1.05; |
| } else { |
| tbwCheat = 1.03; |
| } |
| } else { // DYN_MED_QUALITY |
| // 16b coefficients, 32-64 length |
| // note: > 64 length filters with 16b coefs can have quantization noise problems |
| useS32 = false; |
| stopBandAtten = 84.; |
| if (inSampleRate >= mSampleRate * 4) { |
| halfLength = 32; |
| } else if (inSampleRate >= mSampleRate * 2) { |
| halfLength = 24; |
| } else { |
| halfLength = 16; |
| } |
| if (inSampleRate <= mSampleRate) { |
| tbwCheat = 1.03; |
| } else { |
| tbwCheat = 1.01; |
| } |
| } |
| |
| // determine the number of polyphases in the filterbank. |
| // for 16b, it is desirable to have 2^(16/2) = 256 phases. |
| // https://ccrma.stanford.edu/~jos/resample/Relation_Interpolation_Error_Quantization.html |
| // |
| // We are a bit more lax on this. |
| |
| int phases = mSampleRate / gcd(mSampleRate, inSampleRate); |
| |
| // TODO: Once dynamic sample rate change is an option, the code below |
| // should be modified to execute only when dynamic sample rate change is enabled. |
| // |
| // as above, #phases less than 63 is too few phases for accurate linear interpolation. |
| // we increase the phases to compensate, but more phases means more memory per |
| // filter and more time to compute the filter. |
| // |
| // if we know that the filter will be used for dynamic sample rate changes, |
| // that would allow us skip this part for fixed sample rate resamplers. |
| // |
| while (phases<63) { |
| phases *= 2; // this code only needed to support dynamic rate changes |
| } |
| |
| if (phases>=256) { // too many phases, always interpolate |
| phases = 127; |
| } |
| |
| // create the filter |
| mConstants.set(phases, halfLength, inSampleRate, mSampleRate); |
| createKaiserFir(mConstants, stopBandAtten, |
| inSampleRate, mSampleRate, tbwCheat); |
| } // End Kaiser filter |
| |
| // update phase and state based on the new filter. |
| const Constants& c(mConstants); |
| mInBuffer.resize(mChannelCount, c.mHalfNumCoefs); |
| const uint32_t phaseWrapLimit = c.mL << c.mShift; |
| // try to preserve as much of the phase fraction as possible for on-the-fly changes |
| mPhaseFraction = static_cast<unsigned long long>(mPhaseFraction) |
| * phaseWrapLimit / oldPhaseWrapLimit; |
| mPhaseFraction %= phaseWrapLimit; // should not do anything, but just in case. |
| mPhaseIncrement = static_cast<uint32_t>(static_cast<double>(phaseWrapLimit) |
| * inSampleRate / mSampleRate); |
| |
| // determine which resampler to use |
| // check if locked phase (works only if mPhaseIncrement has no "fractional phase bits") |
| int locked = (mPhaseIncrement << (sizeof(mPhaseIncrement)*8 - c.mShift)) == 0; |
| int stride = (c.mHalfNumCoefs&7)==0 ? 16 : (c.mHalfNumCoefs&3)==0 ? 8 : 2; |
| if (locked) { |
| mPhaseFraction = mPhaseFraction >> c.mShift << c.mShift; // remove fractional phase |
| } |
| |
| setResampler(RESAMPLETYPE(mChannelCount, locked, stride)); |
| #ifdef DEBUG_RESAMPLER |
| printf("channels:%d %s stride:%d %s coef:%d shift:%d\n", |
| mChannelCount, locked ? "locked" : "interpolated", |
| stride, useS32 ? "S32" : "S16", 2*c.mHalfNumCoefs, c.mShift); |
| #endif |
| } |
| |
| template<typename TC, typename TI, typename TO> |
| void AudioResamplerDyn<TC, TI, TO>::resample(int32_t* out, size_t outFrameCount, |
| AudioBufferProvider* provider) |
| { |
| (this->*mResampleFunc)(reinterpret_cast<TO*>(out), outFrameCount, provider); |
| } |
| |
| template<typename TC, typename TI, typename TO> |
| void AudioResamplerDyn<TC, TI, TO>::setResampler(unsigned resampleType) |
| { |
| // stride 16 (falls back to stride 2 for machines that do not support NEON) |
| switch (resampleType) { |
| case RESAMPLETYPE(1, true, 16): |
| mResampleFunc = &AudioResamplerDyn<TC, TI, TO>::resample<1, true, 16>; |
| return; |
| case RESAMPLETYPE(2, true, 16): |
| mResampleFunc = &AudioResamplerDyn<TC, TI, TO>::resample<2, true, 16>; |
| return; |
| case RESAMPLETYPE(1, false, 16): |
| mResampleFunc = &AudioResamplerDyn<TC, TI, TO>::resample<1, false, 16>; |
| return; |
| case RESAMPLETYPE(2, false, 16): |
| mResampleFunc = &AudioResamplerDyn<TC, TI, TO>::resample<2, false, 16>; |
| return; |
| default: |
| LOG_ALWAYS_FATAL("Invalid resampler type: %u", resampleType); |
| mResampleFunc = NULL; |
| return; |
| } |
| } |
| |
| template<typename TC, typename TI, typename TO> |
| template<int CHANNELS, bool LOCKED, int STRIDE> |
| void AudioResamplerDyn<TC, TI, TO>::resample(TO* out, size_t outFrameCount, |
| AudioBufferProvider* provider) |
| { |
| const Constants& c(mConstants); |
| const TC* const coefs = mConstants.mFirCoefs; |
| TI* impulse = mInBuffer.getImpulse(); |
| size_t inputIndex = mInputIndex; |
| uint32_t phaseFraction = mPhaseFraction; |
| const uint32_t phaseIncrement = mPhaseIncrement; |
| size_t outputIndex = 0; |
| size_t outputSampleCount = outFrameCount * 2; // stereo output |
| size_t inFrameCount = getInFrameCountRequired(outFrameCount); |
| const uint32_t phaseWrapLimit = c.mL << c.mShift; |
| |
| // NOTE: be very careful when modifying the code here. register |
| // pressure is very high and a small change might cause the compiler |
| // to generate far less efficient code. |
| // Always sanity check the result with objdump or test-resample. |
| |
| // the following logic is a bit convoluted to keep the main processing loop |
| // as tight as possible with register allocation. |
| while (outputIndex < outputSampleCount) { |
| // buffer is empty, fetch a new one |
| while (mBuffer.frameCount == 0) { |
| mBuffer.frameCount = inFrameCount; |
| provider->getNextBuffer(&mBuffer, |
| calculateOutputPTS(outputIndex / 2)); |
| if (mBuffer.raw == NULL) { |
| goto resample_exit; |
| } |
| if (phaseFraction >= phaseWrapLimit) { // read in data |
| mInBuffer.template readAdvance<CHANNELS>( |
| impulse, c.mHalfNumCoefs, |
| reinterpret_cast<TI*>(mBuffer.raw), inputIndex); |
| phaseFraction -= phaseWrapLimit; |
| while (phaseFraction >= phaseWrapLimit) { |
| inputIndex++; |
| if (inputIndex >= mBuffer.frameCount) { |
| inputIndex -= mBuffer.frameCount; |
| provider->releaseBuffer(&mBuffer); |
| break; |
| } |
| mInBuffer.template readAdvance<CHANNELS>( |
| impulse, c.mHalfNumCoefs, |
| reinterpret_cast<TI*>(mBuffer.raw), inputIndex); |
| phaseFraction -= phaseWrapLimit; |
| } |
| } |
| } |
| const TI* const in = reinterpret_cast<const TI*>(mBuffer.raw); |
| const size_t frameCount = mBuffer.frameCount; |
| const int coefShift = c.mShift; |
| const int halfNumCoefs = c.mHalfNumCoefs; |
| const TO* const volumeSimd = mVolumeSimd; |
| |
| // reread the last input in. |
| mInBuffer.template readAgain<CHANNELS>(impulse, halfNumCoefs, in, inputIndex); |
| |
| // main processing loop |
| while (CC_LIKELY(outputIndex < outputSampleCount)) { |
| // caution: fir() is inlined and may be large. |
| // output will be loaded with the appropriate values |
| // |
| // from the input samples in impulse[-halfNumCoefs+1]... impulse[halfNumCoefs] |
| // from the polyphase filter of (phaseFraction / phaseWrapLimit) in coefs. |
| // |
| fir<CHANNELS, LOCKED, STRIDE>( |
| &out[outputIndex], |
| phaseFraction, phaseWrapLimit, |
| coefShift, halfNumCoefs, coefs, |
| impulse, volumeSimd); |
| outputIndex += 2; |
| |
| phaseFraction += phaseIncrement; |
| while (phaseFraction >= phaseWrapLimit) { |
| inputIndex++; |
| if (inputIndex >= frameCount) { |
| goto done; // need a new buffer |
| } |
| mInBuffer.template readAdvance<CHANNELS>(impulse, halfNumCoefs, in, inputIndex); |
| phaseFraction -= phaseWrapLimit; |
| } |
| } |
| done: |
| // often arrives here when input buffer runs out |
| if (inputIndex >= frameCount) { |
| inputIndex -= frameCount; |
| provider->releaseBuffer(&mBuffer); |
| // mBuffer.frameCount MUST be zero here. |
| } |
| } |
| |
| resample_exit: |
| mInBuffer.setImpulse(impulse); |
| mInputIndex = inputIndex; |
| mPhaseFraction = phaseFraction; |
| } |
| |
| /* instantiate templates used by AudioResampler::create */ |
| template class AudioResamplerDyn<float, float, float>; |
| template class AudioResamplerDyn<int16_t, int16_t, int32_t>; |
| template class AudioResamplerDyn<int32_t, int16_t, int32_t>; |
| |
| // ---------------------------------------------------------------------------- |
| }; // namespace android |