diff options
Diffstat (limited to 'samples/common/src')
-rw-r--r-- | samples/common/src/Audio/AudioCapture.cpp | 96 | ||||
-rw-r--r-- | samples/common/src/Audio/MFCC.cpp | 354 | ||||
-rw-r--r-- | samples/common/src/Audio/MathUtils.cpp | 111 |
3 files changed, 561 insertions, 0 deletions
diff --git a/samples/common/src/Audio/AudioCapture.cpp b/samples/common/src/Audio/AudioCapture.cpp new file mode 100644 index 0000000000..920d7a5233 --- /dev/null +++ b/samples/common/src/Audio/AudioCapture.cpp @@ -0,0 +1,96 @@ +// +// Copyright © 2021 Arm Ltd and Contributors. All rights reserved. +// SPDX-License-Identifier: MIT +// + +#include "AudioCapture.hpp" +#include <alsa/asoundlib.h> +#include <sndfile.h> +#include <samplerate.h> + +namespace audio +{ + std::vector<float> AudioCapture::LoadAudioFile(std::string filePath) + { + SF_INFO inputSoundFileInfo; + SNDFILE* infile = nullptr; + infile = sf_open(filePath.c_str(), SFM_READ, &inputSoundFileInfo); + + float audioIn[inputSoundFileInfo.channels * inputSoundFileInfo.frames]; + sf_read_float(infile, audioIn, inputSoundFileInfo.channels * inputSoundFileInfo.frames); + + float sampleRate = 16000.0f; + float srcRatio = sampleRate / (float)inputSoundFileInfo.samplerate; + int outputFrames = ceilf(inputSoundFileInfo.frames * srcRatio); + + // Convert to mono + std::vector<float> monoData(inputSoundFileInfo.frames); + for(int i = 0; i < inputSoundFileInfo.frames; i++) + { + for(int j = 0; j < inputSoundFileInfo.channels; j++) + monoData[i] += audioIn[i * inputSoundFileInfo.channels + j]; + monoData[i] /= inputSoundFileInfo.channels; + } + + // Resample + SRC_DATA srcData; + srcData.data_in = monoData.data(); + srcData.input_frames = inputSoundFileInfo.frames; + + std::vector<float> dataOut(outputFrames); + srcData.data_out = dataOut.data(); + + srcData.output_frames = outputFrames; + srcData.src_ratio = srcRatio; + + src_simple(&srcData, SRC_SINC_BEST_QUALITY, 1); + + sf_close(infile); + + return dataOut; + } + + void AudioCapture::InitSlidingWindow(float* data, size_t dataSize, int minSamples, size_t stride) + { + this->m_window = SlidingWindow<const float>(data, dataSize, minSamples, stride); + } + + bool AudioCapture::HasNext() + { + return m_window.HasNext(); + } + + std::vector<float> AudioCapture::Next() + { + if (this->m_window.HasNext()) + { + int remainingData = this->m_window.RemainingData(); + const float* windowData = this->m_window.Next(); + + size_t windowSize = this->m_window.GetWindowSize(); + + if(remainingData < windowSize) + { + std::vector<float> audioData(windowSize, 0.0f); + for(int i = 0; i < remainingData; ++i) + { + audioData[i] = *windowData; + if(i < remainingData - 1) + { + ++windowData; + } + } + return audioData; + } + else + { + std::vector<float> audioData(windowData, windowData + windowSize); + return audioData; + } + } + else + { + throw std::out_of_range("Error, end of audio data reached."); + } + } +} //namespace asr
\ No newline at end of file diff --git a/samples/common/src/Audio/MFCC.cpp b/samples/common/src/Audio/MFCC.cpp new file mode 100644 index 0000000000..911c32b26e --- /dev/null +++ b/samples/common/src/Audio/MFCC.cpp @@ -0,0 +1,354 @@ +// +// Copyright © 2020 Arm Ltd and Contributors. All rights reserved. +// SPDX-License-Identifier: MIT +// +#include "MFCC.hpp" +#include "MathUtils.hpp" + +#include <cfloat> +#include <cinttypes> +#include <cstring> + +MfccParams::MfccParams( + const float samplingFreq, + const int numFbankBins, + const float melLoFreq, + const float melHiFreq, + const int numMfccFeats, + const int frameLen, + const bool useHtkMethod, + const int numMfccVectors): + m_samplingFreq(samplingFreq), + m_numFbankBins(numFbankBins), + m_melLoFreq(melLoFreq), + m_melHiFreq(melHiFreq), + m_numMfccFeatures(numMfccFeats), + m_frameLen(frameLen), + m_numMfccVectors(numMfccVectors), + /* Smallest power of 2 >= frame length. */ + m_frameLenPadded(pow(2, ceil((log(frameLen)/log(2))))), + m_useHtkMethod(useHtkMethod) +{} + +std::string MfccParams::Str() +{ + char strC[1024]; + snprintf(strC, sizeof(strC) - 1, "\n \ + \n\t Sampling frequency: %f\ + \n\t Number of filter banks: %u\ + \n\t Mel frequency limit (low): %f\ + \n\t Mel frequency limit (high): %f\ + \n\t Number of MFCC features: %u\ + \n\t Frame length: %u\ + \n\t Padded frame length: %u\ + \n\t Using HTK for Mel scale: %s\n", + this->m_samplingFreq, this->m_numFbankBins, this->m_melLoFreq, + this->m_melHiFreq, this->m_numMfccFeatures, this->m_frameLen, + this->m_frameLenPadded, this->m_useHtkMethod ? "yes" : "no"); + return std::string{strC}; +} + +MFCC::MFCC(const MfccParams& params): + m_params(params), + m_filterBankInitialised(false) +{ + this->m_buffer = std::vector<float>( + this->m_params.m_frameLenPadded, 0.0); + this->m_frame = std::vector<float>( + this->m_params.m_frameLenPadded, 0.0); + this->m_melEnergies = std::vector<float>( + this->m_params.m_numFbankBins, 0.0); + + this->m_windowFunc = std::vector<float>(this->m_params.m_frameLen); + const auto multiplier = static_cast<float>(2 * M_PI / this->m_params.m_frameLen); + + /* Create window function. */ + for (size_t i = 0; i < this->m_params.m_frameLen; i++) + { + this->m_windowFunc[i] = (0.5 - (0.5 * cosf(static_cast<float>(i) * multiplier))); + } + +} + +void MFCC::Init() +{ + this->InitMelFilterBank(); +} + +float MFCC::MelScale(const float freq, const bool useHTKMethod) +{ + if (useHTKMethod) + { + return 1127.0f * logf (1.0f + freq / 700.0f); + } + else + { + /* Slaney formula for mel scale. */ + float mel = freq / ms_freqStep; + + if (freq >= ms_minLogHz) + { + mel = ms_minLogMel + logf(freq / ms_minLogHz) / ms_logStep; + } + return mel; + } +} + +float MFCC::InverseMelScale(const float melFreq, const bool useHTKMethod) +{ + if (useHTKMethod) { + return 700.0f * (expf (melFreq / 1127.0f) - 1.0f); + } + else + { + /* Slaney formula for mel scale. */ + float freq = ms_freqStep * melFreq; + + if (melFreq >= ms_minLogMel) + { + freq = ms_minLogHz * expf(ms_logStep * (melFreq - ms_minLogMel)); + } + return freq; + } +} + + +bool MFCC::ApplyMelFilterBank( + std::vector<float>& fftVec, + std::vector<std::vector<float>>& melFilterBank, + std::vector<uint32_t>& filterBankFilterFirst, + std::vector<uint32_t>& filterBankFilterLast, + std::vector<float>& melEnergies) +{ + const size_t numBanks = melEnergies.size(); + + if (numBanks != filterBankFilterFirst.size() || + numBanks != filterBankFilterLast.size()) + { + printf("unexpected filter bank lengths\n"); + return false; + } + + for (size_t bin = 0; bin < numBanks; ++bin) + { + auto filterBankIter = melFilterBank[bin].begin(); + auto end = melFilterBank[bin].end(); + float melEnergy = FLT_MIN; /* Avoid log of zero at later stages */ + const uint32_t firstIndex = filterBankFilterFirst[bin]; + const uint32_t lastIndex = std::min<uint32_t>(filterBankFilterLast[bin], fftVec.size() - 1); + + for (uint32_t i = firstIndex; i <= lastIndex && filterBankIter != end; i++) + { + float energyRep = sqrt(fftVec[i]); + melEnergy += (*filterBankIter++ * energyRep); + } + + melEnergies[bin] = melEnergy; + } + + return true; +} + +void MFCC::ConvertToLogarithmicScale(std::vector<float>& melEnergies) +{ + for (float& melEnergy : melEnergies) + { + melEnergy = logf(melEnergy); + } +} + +void MFCC::ConvertToPowerSpectrum() +{ + const uint32_t halfDim = this->m_buffer.size() / 2; + + /* Handle this special case. */ + float firstEnergy = this->m_buffer[0] * this->m_buffer[0]; + float lastEnergy = this->m_buffer[1] * this->m_buffer[1]; + + MathUtils::ComplexMagnitudeSquaredF32( + this->m_buffer.data(), + this->m_buffer.size(), + this->m_buffer.data(), + this->m_buffer.size()/2); + + this->m_buffer[0] = firstEnergy; + this->m_buffer[halfDim] = lastEnergy; +} + +std::vector<float> MFCC::CreateDCTMatrix( + const int32_t inputLength, + const int32_t coefficientCount) +{ + std::vector<float> dctMatrix(inputLength * coefficientCount); + + const float normalizer = sqrtf(2.0f/inputLength); + const float angleIncr = M_PI/inputLength; + float angle = 0; + + for (int32_t k = 0, m = 0; k < coefficientCount; k++, m += inputLength) + { + for (int32_t n = 0; n < inputLength; n++) + { + dctMatrix[m + n] = normalizer * cosf((n + 0.5f) * angle); + } + angle += angleIncr; + } + + return dctMatrix; +} + +float MFCC::GetMelFilterBankNormaliser( + const float& leftMel, + const float& rightMel, + const bool useHTKMethod) +{ + /* By default, no normalisation => return 1 */ + return 1.f; +} + +void MFCC::InitMelFilterBank() +{ + if (!this->IsMelFilterBankInited()) + { + this->m_melFilterBank = this->CreateMelFilterBank(); + this->m_dctMatrix = this->CreateDCTMatrix( + this->m_params.m_numFbankBins, + this->m_params.m_numMfccFeatures); + this->m_filterBankInitialised = true; + } +} + +bool MFCC::IsMelFilterBankInited() const +{ + return this->m_filterBankInitialised; +} + +void MFCC::MfccComputePreFeature(const std::vector<float>& audioData) +{ + this->InitMelFilterBank(); + + auto size = std::min(std::min(this->m_frame.size(), audioData.size()), + static_cast<size_t>(this->m_params.m_frameLen)) * sizeof(float); + std::memcpy(this->m_frame.data(), audioData.data(), size); + + /* Apply window function to input frame. */ + for(size_t i = 0; i < this->m_params.m_frameLen; i++) + { + this->m_frame[i] *= this->m_windowFunc[i]; + } + + /* Set remaining frame values to 0. */ + std::fill(this->m_frame.begin() + this->m_params.m_frameLen,this->m_frame.end(), 0); + + /* Compute FFT. */ + MathUtils::FftF32(this->m_frame, this->m_buffer); + + /* Convert to power spectrum. */ + this->ConvertToPowerSpectrum(); + + /* Apply mel filterbanks. */ + if (!this->ApplyMelFilterBank(this->m_buffer, + this->m_melFilterBank, + this->m_filterBankFilterFirst, + this->m_filterBankFilterLast, + this->m_melEnergies)) + { + printf("Failed to apply MEL filter banks\n"); + } + + /* Convert to logarithmic scale. */ + this->ConvertToLogarithmicScale(this->m_melEnergies); +} + +std::vector<float> MFCC::MfccCompute(const std::vector<float>& audioData) +{ + this->MfccComputePreFeature(audioData); + + std::vector<float> mfccOut(this->m_params.m_numMfccFeatures); + + float * ptrMel = this->m_melEnergies.data(); + float * ptrDct = this->m_dctMatrix.data(); + float * ptrMfcc = mfccOut.data(); + + /* Take DCT. Uses matrix mul. */ + for (size_t i = 0, j = 0; i < mfccOut.size(); + ++i, j += this->m_params.m_numFbankBins) + { + *ptrMfcc++ = MathUtils::DotProductF32( + ptrDct + j, + ptrMel, + this->m_params.m_numFbankBins); + } + return mfccOut; +} + +std::vector<std::vector<float>> MFCC::CreateMelFilterBank() +{ + size_t numFftBins = this->m_params.m_frameLenPadded / 2; + float fftBinWidth = static_cast<float>(this->m_params.m_samplingFreq) / this->m_params.m_frameLenPadded; + + float melLowFreq = MFCC::MelScale(this->m_params.m_melLoFreq, + this->m_params.m_useHtkMethod); + float melHighFreq = MFCC::MelScale(this->m_params.m_melHiFreq, + this->m_params.m_useHtkMethod); + float melFreqDelta = (melHighFreq - melLowFreq) / (this->m_params.m_numFbankBins + 1); + + std::vector<float> thisBin = std::vector<float>(numFftBins); + std::vector<std::vector<float>> melFilterBank( + this->m_params.m_numFbankBins); + this->m_filterBankFilterFirst = + std::vector<uint32_t>(this->m_params.m_numFbankBins); + this->m_filterBankFilterLast = + std::vector<uint32_t>(this->m_params.m_numFbankBins); + + for (size_t bin = 0; bin < this->m_params.m_numFbankBins; bin++) + { + float leftMel = melLowFreq + bin * melFreqDelta; + float centerMel = melLowFreq + (bin + 1) * melFreqDelta; + float rightMel = melLowFreq + (bin + 2) * melFreqDelta; + + uint32_t firstIndex = 0; + uint32_t lastIndex = 0; + bool firstIndexFound = false; + const float normaliser = this->GetMelFilterBankNormaliser(leftMel, rightMel, this->m_params.m_useHtkMethod); + + for (size_t i = 0; i < numFftBins; i++) + { + float freq = (fftBinWidth * i); /* Center freq of this fft bin. */ + float mel = MFCC::MelScale(freq, this->m_params.m_useHtkMethod); + thisBin[i] = 0.0; + + if (mel > leftMel && mel < rightMel) + { + float weight; + if (mel <= centerMel) + { + weight = (mel - leftMel) / (centerMel - leftMel); + } + else + { + weight = (rightMel - mel) / (rightMel - centerMel); + } + + thisBin[i] = weight * normaliser; + if (!firstIndexFound) + { + firstIndex = i; + firstIndexFound = true; + } + lastIndex = i; + } + } + + this->m_filterBankFilterFirst[bin] = firstIndex; + this->m_filterBankFilterLast[bin] = lastIndex; + + /* Copy the part we care about. */ + for (uint32_t i = firstIndex; i <= lastIndex; i++) + { + melFilterBank[bin].push_back(thisBin[i]); + } + } + + return melFilterBank; +} diff --git a/samples/common/src/Audio/MathUtils.cpp b/samples/common/src/Audio/MathUtils.cpp new file mode 100644 index 0000000000..d91b5098e1 --- /dev/null +++ b/samples/common/src/Audio/MathUtils.cpp @@ -0,0 +1,111 @@ +// +// Copyright © 2021 Arm Ltd and Contributors. All rights reserved. +// SPDX-License-Identifier: MIT +// + +#include "MathUtils.hpp" +#include <vector> +#include <cmath> +#include <cstdio> + +void MathUtils::FftF32(std::vector<float>& input, + std::vector<float>& fftOutput) +{ + const int inputLength = input.size(); + + for (int k = 0; k <= inputLength / 2; k++) + { + float sumReal = 0, sumImag = 0; + + for (int t = 0; t < inputLength; t++) + { + float angle = 2 * M_PI * t * k / inputLength; + sumReal += input[t] * cosf(angle); + sumImag += -input[t] * sinf(angle); + } + + /* Arrange output to [real0, realN/2, real1, im1, real2, im2, ...] */ + if (k == 0) + { + fftOutput[0] = sumReal; + } + else if (k == inputLength / 2) + { + fftOutput[1] = sumReal; + } + else + { + fftOutput[k*2] = sumReal; + fftOutput[k*2 + 1] = sumImag; + }; + } +} + +float MathUtils::DotProductF32(const float* srcPtrA, float* srcPtrB, + const int srcLen) +{ + float output = 0.f; + + for (int i = 0; i < srcLen; ++i) + { + output += *srcPtrA++ * *srcPtrB++; + } + return output; +} + +bool MathUtils::ComplexMagnitudeSquaredF32(const float* ptrSrc, + int srcLen, + float* ptrDst, + int dstLen) +{ + if (dstLen < srcLen/2) + { + printf("dstLen must be greater than srcLen/2"); + return false; + } + + for (int j = 0; j < dstLen; ++j) + { + const float real = *ptrSrc++; + const float im = *ptrSrc++; + *ptrDst++ = real*real + im*im; + } + return true; +} + +void MathUtils::VecLogarithmF32(std::vector <float>& input, + std::vector <float>& output) +{ + for (auto in = input.begin(), out = output.begin(); + in != input.end(); ++in, ++out) + { + *out = logf(*in); + } +} + +float MathUtils::MeanF32(const float* ptrSrc, const uint32_t srcLen) +{ + if (!srcLen) + { + return 0.f; + } + + float acc = std::accumulate(ptrSrc, ptrSrc + srcLen, 0.0); + return acc/srcLen; +} + +float MathUtils::StdDevF32(const float* ptrSrc, uint32_t srcLen, float mean) +{ + if (!srcLen) + { + return 0.f; + } + auto VarianceFunction = [mean, srcLen](float acc, const float value) { + return acc + (((value - mean) * (value - mean))/ srcLen); + }; + + float acc = std::accumulate(ptrSrc, ptrSrc + srcLen, 0.0, + VarianceFunction); + return sqrtf(acc); +} + |