diff options
Diffstat (limited to 'samples/common/include/Audio')
| -rw-r--r-- | samples/common/include/Audio/AudioCapture.hpp | 57 | ||||
| -rw-r--r-- | samples/common/include/Audio/DataStructures.hpp | 102 | ||||
| -rw-r--r-- | samples/common/include/Audio/MFCC.hpp | 234 | ||||
| -rw-r--r-- | samples/common/include/Audio/MathUtils.hpp | 85 | ||||
| -rw-r--r-- | samples/common/include/Audio/SlidingWindow.hpp | 161 |
5 files changed, 639 insertions, 0 deletions
diff --git a/samples/common/include/Audio/AudioCapture.hpp b/samples/common/include/Audio/AudioCapture.hpp new file mode 100644 index 0000000000..898bf911f4 --- /dev/null +++ b/samples/common/include/Audio/AudioCapture.hpp @@ -0,0 +1,57 @@ +// +// Copyright © 2021 Arm Ltd and Contributors. All rights reserved. +// SPDX-License-Identifier: MIT +// + +#pragma once + +#include <string> +#include <iostream> +#include <cmath> +#include <vector> +#include <exception> + +#include "SlidingWindow.hpp" + +namespace audio +{ + +/** +* @brief Class used to capture the audio data loaded from file, and to provide a method of + * extracting correctly positioned and appropriately sized audio windows +* +*/ + class AudioCapture + { + public: + + SlidingWindow<const float> m_window; + + /** + * @brief Default constructor + */ + AudioCapture() = default; + + /** + * @brief Function to load the audio data captured from the + * input file to memory. + */ + static std::vector<float> LoadAudioFile(std::string filePath); + + /** + * @brief Function to initialize the sliding window. This will set its position in memory, its + * window size and its stride. + */ + void InitSlidingWindow(float* data, size_t dataSize, int minSamples, size_t stride); + + /** + * Checks whether there is another block of audio in memory to read + */ + bool HasNext(); + + /** + * Retrieves the next block of audio if its available + */ + std::vector<float> Next(); + }; +} // namespace audio
\ No newline at end of file diff --git a/samples/common/include/Audio/DataStructures.hpp b/samples/common/include/Audio/DataStructures.hpp new file mode 100644 index 0000000000..9922265299 --- /dev/null +++ b/samples/common/include/Audio/DataStructures.hpp @@ -0,0 +1,102 @@ +// +// Copyright © 2020 Arm Ltd and Contributors. All rights reserved. +// SPDX-License-Identifier: MIT +// +#pragma once + +#include <stdio.h> +#include <iterator> + +/** + * Class Array2d is a data structure that represents a two dimensional array. + * The data is allocated in contiguous memory, arranged row-wise + * and individual elements can be accessed with the () operator. + * For example a two dimensional array D of size (M, N) can be accessed: + * + * _|<------------- col size = N -------->| + * | D(r=0, c=0) D(r=0, c=1)... D(r=0, c=N) + * | D(r=1, c=0) D(r=1, c=1)... D(r=1, c=N) + * | ... + * row size = M ... + * | ... + * _ D(r=M, c=0) D(r=M, c=1)... D(r=M, c=N) + * + */ +template<typename T> +class Array2d +{ +private: + size_t m_rows; + size_t m_cols; + T* m_data; + +public: + /** + * Creates the array2d with the given sizes. + * + * @param rows number of rows. + * @param cols number of columns. + */ + Array2d(unsigned rows, unsigned cols) + { + if (rows == 0 || cols == 0) { + printf("Array2d constructor has 0 size.\n"); + m_data = nullptr; + return; + } + m_rows = rows; + m_cols = cols; + m_data = new T[rows * cols]; + } + + ~Array2d() + { + delete[] m_data; + } + + T& operator() (unsigned int row, unsigned int col) + { + return m_data[m_cols * row + col]; + } + + T operator() (unsigned int row, unsigned int col) const + { + return m_data[m_cols * row + col]; + } + + /** + * Gets rows number of the current array2d. + * @return number of rows. + */ + size_t size(size_t dim) + { + switch (dim) + { + case 0: + return m_rows; + case 1: + return m_cols; + default: + return 0; + } + } + + /** + * Gets the array2d total size. + */ + size_t totalSize() + { + return m_rows * m_cols; + } + + /** + * array2d iterator. + */ + using iterator=T*; + using const_iterator=T const*; + + iterator begin() { return m_data; } + iterator end() { return m_data + totalSize(); } + const_iterator begin() const { return m_data; } + const_iterator end() const { return m_data + totalSize(); }; +}; diff --git a/samples/common/include/Audio/MFCC.hpp b/samples/common/include/Audio/MFCC.hpp new file mode 100644 index 0000000000..468bf92fae --- /dev/null +++ b/samples/common/include/Audio/MFCC.hpp @@ -0,0 +1,234 @@ +// +// Copyright © 2020 Arm Ltd and Contributors. All rights reserved. +// SPDX-License-Identifier: MIT +// +#pragma once + + +#include <vector> +#include <cstdint> +#include <cmath> +#include <limits> +#include <string> + +/* MFCC's consolidated parameters */ +class MfccParams +{ +public: + float m_samplingFreq; + int m_numFbankBins; + float m_melLoFreq; + float m_melHiFreq; + int m_numMfccFeatures; + int m_frameLen; + int m_frameLenPadded; + bool m_useHtkMethod; + int m_numMfccVectors; + /** @brief Constructor */ + 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); + /* Delete the default constructor */ + MfccParams() = delete; + /* Default destructor */ + ~MfccParams() = default; + /** @brief String representation of parameters */ + std::string Str(); +}; + +/** + * @brief Class for MFCC feature extraction. + * Based on https://github.com/ARM-software/ML-KWS-for-MCU/blob/master/Deployment/Source/MFCC/mfcc.cpp + * This class is designed to be generic and self-sufficient but + * certain calculation routines can be overridden to accommodate + * use-case specific requirements. + */ +class MFCC { +public: + /** + * @brief Constructor + * @param[in] params MFCC parameters + */ + explicit MFCC(const MfccParams& params); + + MFCC() = delete; + + ~MFCC() = default; + + /** + * @brief Extract MFCC features for one single small frame of + * audio data e.g. 640 samples. + * @param[in] audioData Vector of audio samples to calculate + * features for. + * @return Vector of extracted MFCC features. + **/ + std::vector<float> MfccCompute(const std::vector<float>& audioData); + + /** @brief Initialise. */ + void Init(); + + /** + * @brief Extract MFCC features and quantise for one single small + * frame of audio data e.g. 640 samples. + * @param[in] audioData Vector of audio samples to calculate + * features for. + * @param[in] quantScale Quantisation scale. + * @param[in] quantOffset Quantisation offset. + * @return Vector of extracted quantised MFCC features. + **/ + template<typename T> + std::vector<T> MfccComputeQuant(const std::vector<float>& audioData, + const float quantScale, + const int quantOffset) + { + this->MfccComputePreFeature(audioData); + float minVal = std::numeric_limits<T>::min(); + float maxVal = std::numeric_limits<T>::max(); + + std::vector<T> mfccOut(this->m_params.m_numMfccFeatures); + const size_t numFbankBins = this->m_params.m_numFbankBins; + + /* Take DCT. Uses matrix mul. */ + for (size_t i = 0, j = 0; i < mfccOut.size(); ++i, j += numFbankBins) + { + float sum = 0; + for (size_t k = 0; k < numFbankBins; ++k) + { + sum += this->m_dctMatrix[j + k] * this->m_melEnergies[k]; + } + /* Quantize to T. */ + sum = std::round((sum / quantScale) + quantOffset); + mfccOut[i] = static_cast<T>(std::min<float>(std::max<float>(sum, minVal), maxVal)); + } + + return mfccOut; + } + + MfccParams m_params; + + /* Constants */ + static constexpr float ms_logStep = /*logf(6.4)*/ 1.8562979903656 / 27.0; + static constexpr float ms_freqStep = 200.0 / 3; + static constexpr float ms_minLogHz = 1000.0; + static constexpr float ms_minLogMel = ms_minLogHz / ms_freqStep; + +protected: + /** + * @brief Project input frequency to Mel Scale. + * @param[in] freq Input frequency in floating point. + * @param[in] useHTKMethod bool to signal if HTK method is to be + * used for calculation. + * @return Mel transformed frequency in floating point. + **/ + static float MelScale(float freq, + bool useHTKMethod = true); + + /** + * @brief Inverse Mel transform - convert MEL warped frequency + * back to normal frequency. + * @param[in] melFreq Mel frequency in floating point. + * @param[in] useHTKMethod bool to signal if HTK method is to be + * used for calculation. + * @return Real world frequency in floating point. + **/ + static float InverseMelScale(float melFreq, + bool useHTKMethod = true); + + /** + * @brief Populates MEL energies after applying the MEL filter + * bank weights and adding them up to be placed into + * bins, according to the filter bank's first and last + * indices (pre-computed for each filter bank element + * by CreateMelFilterBank function). + * @param[in] fftVec Vector populated with FFT magnitudes. + * @param[in] melFilterBank 2D Vector with filter bank weights. + * @param[in] filterBankFilterFirst Vector containing the first indices of filter bank + * to be used for each bin. + * @param[in] filterBankFilterLast Vector containing the last indices of filter bank + * to be used for each bin. + * @param[out] melEnergies Pre-allocated vector of MEL energies to be + * populated. + * @return true if successful, false otherwise. + */ + virtual bool 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); + + /** + * @brief Converts the Mel energies for logarithmic scale. + * @param[in,out] melEnergies 1D vector of Mel energies. + **/ + virtual void ConvertToLogarithmicScale(std::vector<float>& melEnergies); + + /** + * @brief Create a matrix used to calculate Discrete Cosine + * Transform. + * @param[in] inputLength Input length of the buffer on which + * DCT will be performed. + * @param[in] coefficientCount Total coefficients per input length. + * @return 1D vector with inputLength x coefficientCount elements + * populated with DCT coefficients. + */ + virtual std::vector<float> CreateDCTMatrix( + int32_t inputLength, + int32_t coefficientCount); + + /** + * @brief Given the low and high Mel values, get the normaliser + * for weights to be applied when populating the filter + * bank. + * @param[in] leftMel Low Mel frequency value. + * @param[in] rightMel High Mel frequency value. + * @param[in] useHTKMethod bool to signal if HTK method is to be + * used for calculation. + * @return Value to use for normalizing. + */ + virtual float GetMelFilterBankNormaliser( + const float& leftMel, + const float& rightMel, + bool useHTKMethod); + +private: + + std::vector<float> m_frame; + std::vector<float> m_buffer; + std::vector<float> m_melEnergies; + std::vector<float> m_windowFunc; + std::vector<std::vector<float>> m_melFilterBank; + std::vector<float> m_dctMatrix; + std::vector<uint32_t> m_filterBankFilterFirst; + std::vector<uint32_t> m_filterBankFilterLast; + bool m_filterBankInitialised; + + /** + * @brief Initialises the filter banks and the DCT matrix. **/ + void InitMelFilterBank(); + + /** + * @brief Signals whether the instance of MFCC has had its + * required buffers initialised. + * @return true if initialised, false otherwise. + **/ + bool IsMelFilterBankInited() const; + + /** + * @brief Create mel filter banks for MFCC calculation. + * @return 2D vector of floats. + **/ + std::vector<std::vector<float>> CreateMelFilterBank(); + + /** + * @brief Computes and populates internal memeber buffers used + * in MFCC feature calculation + * @param[in] audioData 1D vector of 16-bit audio data. + */ + void MfccComputePreFeature(const std::vector<float>& audioData); + + /** @brief Computes the magnitude from an interleaved complex array. */ + void ConvertToPowerSpectrum(); + +}; diff --git a/samples/common/include/Audio/MathUtils.hpp b/samples/common/include/Audio/MathUtils.hpp new file mode 100644 index 0000000000..1d8b0d31cc --- /dev/null +++ b/samples/common/include/Audio/MathUtils.hpp @@ -0,0 +1,85 @@ +// +// Copyright © 2020 Arm Ltd and Contributors. All rights reserved. +// SPDX-License-Identifier: MIT +// + +#include <vector> +#include <cmath> +#include <cstdint> +#include <numeric> + +class MathUtils +{ + +public: + + /** + * @brief Computes the FFT for the input vector + * @param[in] input Floating point vector of input elements + * @param[out] fftOutput Output buffer to be populated by computed + * FFTs + * @return none + */ + static void FftF32(std::vector<float>& input, + std::vector<float>& fftOutput); + + + /** + * @brief Computes the dot product of two 1D floating point + * vectors. + * result = sum(srcA[0]*srcB[0] + srcA[1]*srcB[1] + ..) + * @param[in] srcPtrA pointer to the first element of first + * array + * @param[in] srcPtrB pointer to the first element of second + * array + * @param[in] srcLen Number of elements in the array/vector + * @return dot product + */ + static float DotProductF32(const float* srcPtrA, float* srcPtrB, + int srcLen); + + /** + * @brief Computes the squared magnitude of floating point + * complex number array. + * @param[in] ptrSrc pointer to the first element of input + * array + * @param[in] srcLen Number of elements in the array/vector + * @param[out] ptrDst Output buffer to be populated + * @param[in] dstLen output buffer len (for sanity check only) + * @return true if successful, false otherwise + */ + static bool ComplexMagnitudeSquaredF32(const float* ptrSrc, + int srcLen, + float* ptrDst, + int dstLen); + + /** + * @brief Computes the natural logarithms of input floating point + * vector + * @param[in] input Floating point input vector + * @param[out] output Pre-allocated buffer to be populated with + * natural log values of each input element + * @return none + */ + static void VecLogarithmF32(std::vector <float>& input, + std::vector <float>& output); + + /** + * @brief Gets the mean of a floating point array of elements + * @param[in] ptrSrc pointer to the first element + * @param[in] srcLen Number of elements in the array/vector + * @return average value + */ + static float MeanF32(const float* ptrSrc, uint32_t srcLen); + + /** + * @brief Gets the standard deviation of a floating point array + * of elements + * @param[in] ptrSrc pointer to the first element + * @param[in] srcLen Number of elements in the array/vector + * @param[in] mean pre-computed mean value + * @return standard deviation value + */ + static float StdDevF32(const float* ptrSrc, uint32_t srcLen, + float mean); +}; diff --git a/samples/common/include/Audio/SlidingWindow.hpp b/samples/common/include/Audio/SlidingWindow.hpp new file mode 100644 index 0000000000..77498c6338 --- /dev/null +++ b/samples/common/include/Audio/SlidingWindow.hpp @@ -0,0 +1,161 @@ +// +// Copyright © 2021 Arm Ltd and Contributors. All rights reserved. +// SPDX-License-Identifier: MIT +// + +#pragma once + +template<class T> +class SlidingWindow +{ +protected: + T* m_start = nullptr; + size_t m_dataSize = 0; + size_t m_size = 0; + size_t m_stride = 0; + size_t m_count = 0; +public: + + /** + * Creates the window slider through the given data. + * + * @param data pointer to the data to slide through. + * @param dataSize size in T type elements wise. + * @param windowSize sliding window size in T type wise elements. + * @param stride stride size in T type wise elements. + */ + SlidingWindow(T* data, size_t dataSize, + size_t windowSize, size_t stride) + { + m_start = data; + m_dataSize = dataSize; + m_size = windowSize; + m_stride = stride; + } + + SlidingWindow() = default; + + ~SlidingWindow() = default; + + /** + * Get the next data window. + * @return pointer to the next window, if next window is not available nullptr is returned. + */ + virtual T* Next() + { + if (HasNext()) + { + m_count++; + return m_start + Index() * m_stride; + } + else + { + return nullptr; + } + } + + /** + * Checks if the next data portion is available. + * @return true if next data portion is available + */ + bool HasNext() + { + return this->m_count < 1 + this->FractionalTotalStrides() && (this->NextWindowStartIndex() < this->m_dataSize); + } + + /** + * Resest the slider to the initial position. + */ + virtual void Reset() + { + m_count = 0; + } + + /** + * Resest the slider to the initial position. + */ + virtual size_t GetWindowSize() + { + return m_size; + } + + /** + * Resets the slider to the start of the new data. + * New data size MUST be the same as the old one. + * @param newStart pointer to the new data to slide through. + */ + virtual void Reset(T* newStart) + { + m_start = newStart; + Reset(); + } + + /** + * Gets current index of the sliding window. + * @return current position of the sliding window in number of strides + */ + size_t Index() + { + return m_count == 0? 0: m_count - 1; + } + + /** + * Gets the index from the start of the data where the next window will begin. + * While Index() returns the index of sliding window itself this function returns the index of the data + * element itself. + * @return Index from the start of the data where the next sliding window will begin. + */ + virtual size_t NextWindowStartIndex() + { + return m_count == 0? 0: ((m_count) * m_stride); + } + + /** + * Go to given sliding window index. + * @param index new position of the sliding window. if index is invalid (greater than possible range of strides) + * then next call to Next() will return nullptr. + */ + void FastForward(size_t index) + { + m_count = index; + } + + /** + * Calculates whole number of times the window can stride through the given data. + * @return maximum number of strides. + */ + size_t TotalStrides() + { + if (m_size > m_dataSize) + { + return 0; + } + return ((m_dataSize - m_size)/m_stride); + } + + /** + * Calculates number of times the window can stride through the given data. May not be a whole number. + * @return Number of strides to cover all data. + */ + float FractionalTotalStrides() + { + if(this->m_size > this->m_dataSize) + { + return this->m_dataSize / this->m_size; + } + else + { + return ((this->m_dataSize - this->m_size)/ static_cast<float>(this->m_stride)); + } + + } + + /** + * Calculates the remaining data left to be processed + * @return The remaining unprocessed data + */ + int RemainingData() + { + return this->m_dataSize - this->NextWindowStartIndex(); + } +};
\ No newline at end of file |