MLECO-3183: Refactoring application sources

Platform agnostic application sources are moved into application
api module with their own independent CMake projects.

Changes for MLECO-3080 also included - they create CMake projects
individial API's (again, platform agnostic) that dependent on the
common logic. The API for KWS_API "joint" API has been removed and
now the use case relies on individual KWS, and ASR API libraries.

Change-Id: I1f7748dc767abb3904634a04e0991b74ac7b756d
Signed-off-by: Kshitij Sisodia <kshitij.sisodia@arm.com>

4 files changed, 0 insertions, 620 deletions

diff --git a/source/use_case/ad/include/AdMelSpectrogram.hpp b/source/use_case/ad/include/AdMelSpectrogram.hpp
deleted file mode 100644
index 05c5bfc..0000000
--- a/source/use_case/ad/include/AdMelSpectrogram.hpp
+++ /dev/null
@@ -1,97 +0,0 @@
-/*
- * Copyright (c) 2021 Arm Limited. All rights reserved.
- * SPDX-License-Identifier: Apache-2.0
- *
- * 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.
- */
-#ifndef ADMELSPECTROGRAM_HPP
-#define ADMELSPECTROGRAM_HPP
-
-#include "MelSpectrogram.hpp"
-
-namespace arm {
-namespace app {
-namespace audio {
-
-    /* Class to provide anomaly detection specific Mel Spectrogram calculation requirements */
-    class AdMelSpectrogram : public MelSpectrogram {
-
-    public:
-        static constexpr uint32_t  ms_defaultSamplingFreq = 16000;
-        static constexpr uint32_t  ms_defaultNumFbankBins =    64;
-        static constexpr uint32_t  ms_defaultMelLoFreq    =     0;
-        static constexpr uint32_t  ms_defaultMelHiFreq    =  8000;
-        static constexpr bool      ms_defaultUseHtkMethod = false;
-
-        explicit AdMelSpectrogram(const size_t frameLen)
-                :  MelSpectrogram(MelSpecParams(
-                ms_defaultSamplingFreq, ms_defaultNumFbankBins,
-                ms_defaultMelLoFreq, ms_defaultMelHiFreq,
-                frameLen, ms_defaultUseHtkMethod))
-        {}
-
-        AdMelSpectrogram()  = delete;
-        ~AdMelSpectrogram() = default;
-
-    protected:
-
-        /**
-         * @brief       Overrides base class implementation of this 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) override;
-
-        /**
-         * @brief       Override for the base class implementation convert mel
-         *              energies to logarithmic scale. The difference from
-         *              default behaviour is that the power is converted to dB
-         *              and subsequently clamped.
-         * @param[in,out]   melEnergies - 1D vector of Mel energies
-         **/
-        virtual void ConvertToLogarithmicScale(std::vector<float>& melEnergies) override;
-
-        /**
-         * @brief       Given the low and high Mel values, get the normaliser
-         *              for weights to be applied when populating the filter
-         *              bank. Override for the base class implementation.
-         * @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      Return float value to be applied 
-         *              when populating the filter bank.
-         */
-        virtual float GetMelFilterBankNormaliser(
-                const float&   leftMel,
-                const float&   rightMel,
-                const bool     useHTKMethod) override;
-    };
-
-} /* namespace audio */
-} /* namespace app */
-} /* namespace arm */
-
-#endif /* ADMELSPECTROGRAM_HPP */
diff --git a/source/use_case/ad/include/AdModel.hpp b/source/use_case/ad/include/AdModel.hpp
deleted file mode 100644
index 2195a7c..0000000
--- a/source/use_case/ad/include/AdModel.hpp
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
- * Copyright (c) 2021-2022 Arm Limited. All rights reserved.
- * SPDX-License-Identifier: Apache-2.0
- *
- * 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.
- */
-#ifndef AD_MODEL_HPP
-#define AD_MODEL_HPP
-
-#include "Model.hpp"
-
-extern const int g_FrameLength;
-extern const int g_FrameStride;
-extern const float g_ScoreThreshold;
-extern const float g_TrainingMean;
-
-namespace arm {
-namespace app {
-
-    class AdModel : public Model {
-
-    public:
-        /* Indices for the expected model - based on input tensor shape */
-        static constexpr uint32_t ms_inputRowsIdx = 1;
-        static constexpr uint32_t ms_inputColsIdx = 2;
-
-    protected:
-        /** @brief   Gets the reference to op resolver interface class */
-        const tflite::MicroOpResolver& GetOpResolver() override;
-
-        /** @brief   Adds operations to the op resolver instance */
-        bool EnlistOperations() override;
-
-        const uint8_t* ModelPointer() override;
-
-        size_t ModelSize() override;
-
-    private:
-        /* Maximum number of individual operations that can be enlisted */
-        static constexpr int ms_maxOpCnt = 6;
-
-        /* A mutable op resolver instance */
-        tflite::MicroMutableOpResolver<ms_maxOpCnt> m_opResolver;
-    };
-
-} /* namespace app */
-} /* namespace arm */
-
-#endif /* AD_MODEL_HPP */
diff --git a/source/use_case/ad/include/AdProcessing.hpp b/source/use_case/ad/include/AdProcessing.hpp
deleted file mode 100644
index 9abf6f1..0000000
--- a/source/use_case/ad/include/AdProcessing.hpp
+++ /dev/null
@@ -1,230 +0,0 @@
-/*
- * Copyright (c) 2022 Arm Limited. All rights reserved.
- * SPDX-License-Identifier: Apache-2.0
- *
- * 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.
- */
-#ifndef AD_PROCESSING_HPP
-#define AD_PROCESSING_HPP
-
-#include "BaseProcessing.hpp"
-#include "AudioUtils.hpp"
-#include "AdMelSpectrogram.hpp"
-#include "log_macros.h"
-
-namespace arm {
-namespace app {
-
-    /**
-     * @brief   Pre-processing class for anomaly detection use case.
-     *          Implements methods declared by BasePreProcess and anything else needed
-     *          to populate input tensors ready for inference.
-     */
-    class AdPreProcess : public BasePreProcess {
-
-    public:
-        /**
-         * @brief Constructor for AdPreProcess class objects
-         * @param[in] inputTensor  input tensor pointer from the tensor arena.
-         * @param[in] melSpectrogramFrameLen MEL spectrogram's frame length
-         * @param[in] melSpectrogramFrameStride MEL spectrogram's frame stride
-         * @param[in] adModelTrainingMean Training mean for the Anomaly detection model being used.
-         */
-        explicit AdPreProcess(TfLiteTensor* inputTensor,
-                              uint32_t melSpectrogramFrameLen,
-                              uint32_t melSpectrogramFrameStride,
-                              float adModelTrainingMean);
-
-        ~AdPreProcess() = default;
-
-        /**
-         * @brief Function to invoke pre-processing and populate the input vector
-         * @param input pointer to input data. For anomaly detection, this is the pointer to
-         *              the audio data.
-         * @param inputSize Size of the data being passed in for pre-processing.
-         * @return True if successful, false otherwise.
-         */
-        bool DoPreProcess(const void* input, size_t inputSize) override;
-
-        /**
-         * @brief Getter function for audio window size computed when constructing
-         *        the class object.
-         * @return Audio window size as 32 bit unsigned integer.
-         */
-        uint32_t GetAudioWindowSize();
-
-        /**
-         * @brief Getter function for audio window stride computed when constructing
-         *        the class object.
-         * @return Audio window stride as 32 bit unsigned integer.
-         */
-        uint32_t GetAudioDataStride();
-
-        /**
-         * @brief Setter function for current audio index. This is only used for evaluating
-         *        if previously computed features can be re-used from cache.
-         */
-        void SetAudioWindowIndex(uint32_t idx);
-
-    private:
-        bool        m_validInstance{false}; /**< Indicates the current object is valid. */
-        uint32_t    m_melSpectrogramFrameLen{}; /**< MEL spectrogram's window frame length */
-        uint32_t    m_melSpectrogramFrameStride{}; /**< MEL spectrogram's window frame stride */
-        uint8_t     m_inputResizeScale{}; /**< Downscaling factor for the MEL energy matrix. */
-        uint32_t    m_numMelSpecVectorsInAudioStride{};  /**< Number of frames to move across the audio. */
-        uint32_t    m_audioDataWindowSize{}; /**< Audio window size computed based on other parameters. */
-        uint32_t    m_audioDataStride{}; /**< Audio window stride computed. */
-        uint32_t    m_numReusedFeatureVectors{}; /**< Number of MEL vectors that can be re-used */
-        uint32_t    m_audioWindowIndex{}; /**< Current audio window index (from audio's sliding window) */
-
-        audio::SlidingWindow<const int16_t> m_melWindowSlider; /**< Internal MEL spectrogram window slider */
-        audio::AdMelSpectrogram m_melSpec; /**< MEL spectrogram computation object */
-        std::function<void
-            (std::vector<int16_t>&, int, bool, size_t, size_t)> m_featureCalc; /**< Feature calculator object */
-    };
-
-    class AdPostProcess : public BasePostProcess {
-    public:
-        /**
-         * @brief Constructor for AdPostProcess object.
-         * @param[in] outputTensor Output tensor pointer.
-         */
-        explicit AdPostProcess(TfLiteTensor* outputTensor);
-
-        ~AdPostProcess() = default;
-
-        /**
-         * @brief Function to do the post-processing on the output tensor.
-         * @return True if successful, false otherwise.
-         */
-        bool DoPostProcess() override;
-
-        /**
-         * @brief Getter function for an element from the de-quantised output vector.
-         * @param index Index of the element to be retrieved.
-         * @return index represented as a 32 bit floating point number.
-         */
-        float GetOutputValue(uint32_t index);
-
-    private:
-        TfLiteTensor* m_outputTensor{}; /**< Output tensor pointer */
-        std::vector<float> m_dequantizedOutputVec{}; /**< Internal output vector */
-
-        /**
-         * @brief De-quantizes and flattens the output tensor into a vector.
-         * @tparam T template parameter to indicate data type.
-         * @return True if successful, false otherwise.
-         */
-        template<typename T>
-        bool Dequantize()
-        {
-            TfLiteTensor* tensor = this->m_outputTensor;
-            if (tensor == nullptr) {
-                printf_err("Invalid output tensor.\n");
-                return false;
-            }
-            T* tensorData = tflite::GetTensorData<T>(tensor);
-
-            uint32_t totalOutputSize = 1;
-            for (int inputDim = 0; inputDim < tensor->dims->size; inputDim++){
-                totalOutputSize *= tensor->dims->data[inputDim];
-            }
-
-            /* For getting the floating point values, we need quantization parameters */
-            QuantParams quantParams = GetTensorQuantParams(tensor);
-
-            this->m_dequantizedOutputVec = std::vector<float>(totalOutputSize, 0);
-
-            for (size_t i = 0; i < totalOutputSize; ++i) {
-                this->m_dequantizedOutputVec[i] = quantParams.scale * (tensorData[i] - quantParams.offset);
-            }
-
-            return true;
-        }
-    };
-
-    /* Templated instances available: */
-    template bool AdPostProcess::Dequantize<int8_t>();
-
-    /**
-     * @brief Generic feature calculator factory.
-     *
-     * Returns lambda function to compute features using features cache.
-     * Real features math is done by a lambda function provided as a parameter.
-     * Features are written to input tensor memory.
-     *
-     * @tparam T            feature vector type.
-     * @param inputTensor   model input tensor pointer.
-     * @param cacheSize     number of feature vectors to cache. Defined by the sliding window overlap.
-     * @param compute       features calculator function.
-     * @return              lambda function to compute features.
-     */
-    template<class T>
-    std::function<void (std::vector<int16_t>&, size_t, bool, size_t, size_t)>
-    FeatureCalc(TfLiteTensor* inputTensor, size_t cacheSize,
-                std::function<std::vector<T> (std::vector<int16_t>& )> compute)
-    {
-        /* Feature cache to be captured by lambda function*/
-        static std::vector<std::vector<T>> featureCache = std::vector<std::vector<T>>(cacheSize);
-
-        return [=](std::vector<int16_t>& audioDataWindow,
-                   size_t index,
-                   bool useCache,
-                   size_t featuresOverlapIndex,
-                   size_t resizeScale)
-        {
-            T* tensorData = tflite::GetTensorData<T>(inputTensor);
-            std::vector<T> features;
-
-            /* Reuse features from cache if cache is ready and sliding windows overlap.
-             * Overlap is in the beginning of sliding window with a size of a feature cache. */
-            if (useCache && index < featureCache.size()) {
-                features = std::move(featureCache[index]);
-            } else {
-                features = std::move(compute(audioDataWindow));
-            }
-            auto size = features.size() / resizeScale;
-            auto sizeBytes = sizeof(T);
-
-            /* Input should be transposed and "resized" by skipping elements. */
-            for (size_t outIndex = 0; outIndex < size; outIndex++) {
-                std::memcpy(tensorData + (outIndex*size) + index, &features[outIndex*resizeScale], sizeBytes);
-            }
-
-            /* Start renewing cache as soon iteration goes out of the windows overlap. */
-            if (index >= featuresOverlapIndex / resizeScale) {
-                featureCache[index - featuresOverlapIndex / resizeScale] = std::move(features);
-            }
-        };
-    }
-
-    template std::function<void (std::vector<int16_t>&, size_t , bool, size_t, size_t)>
-    FeatureCalc<int8_t>(TfLiteTensor* inputTensor,
-                        size_t cacheSize,
-                        std::function<std::vector<int8_t> (std::vector<int16_t>&)> compute);
-
-    template std::function<void(std::vector<int16_t>&, size_t, bool, size_t, size_t)>
-    FeatureCalc<float>(TfLiteTensor *inputTensor,
-                       size_t cacheSize,
-                       std::function<std::vector<float>(std::vector<int16_t>&)> compute);
-
-    std::function<void (std::vector<int16_t>&, int, bool, size_t, size_t)>
-    GetFeatureCalculator(audio::AdMelSpectrogram& melSpec,
-                         TfLiteTensor* inputTensor,
-                         size_t cacheSize,
-                         float trainingMean);
-
-} /* namespace app */
-} /* namespace arm */
-
-#endif /* AD_PROCESSING_HPP */
diff --git a/source/use_case/ad/include/MelSpectrogram.hpp b/source/use_case/ad/include/MelSpectrogram.hpp
deleted file mode 100644
index d3ea3f7..0000000
--- a/source/use_case/ad/include/MelSpectrogram.hpp
+++ /dev/null
@@ -1,234 +0,0 @@
-/*
- * Copyright (c) 2021 Arm Limited. All rights reserved.
- * SPDX-License-Identifier: Apache-2.0
- *
- * 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.
- */
-#ifndef MELSPECTROGRAM_HPP
-#define MELSPECTROGRAM_HPP
-
-#include "PlatformMath.hpp"
-
-#include <vector>
-#include <cstdint>
-#include <cmath>
-#include <limits>
-#include <string>
-
-namespace arm {
-namespace app {
-namespace audio {
-
-    /* Mel Spectrogram consolidated parameters */
-    class MelSpecParams {
-    public:
-        float       m_samplingFreq;
-        uint32_t    m_numFbankBins;
-        float       m_melLoFreq;
-        float       m_melHiFreq;
-        uint32_t    m_frameLen;
-        uint32_t    m_frameLenPadded;
-        bool        m_useHtkMethod;
-
-        /** @brief  Constructor */
-        MelSpecParams(const float samplingFreq, const uint32_t numFbankBins,
-                      const float melLoFreq, const float melHiFreq,
-                      const uint32_t frameLen, const bool useHtkMethod);
-
-        MelSpecParams()  = delete;
-        ~MelSpecParams() = default;
-
-        /** @brief  String representation of parameters */
-        std::string Str() const;
-    };
-
-    /**
-     * @brief   Class for Mel Spectrogram 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 MelSpectrogram {
-
-    public:
-        /**
-        * @brief        Extract Mel Spectrogram 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]    trainingMean    Value to subtract from the the computed mel spectrogram, default 0.
-        * @return       Vector of extracted Mel Spectrogram features.
-        **/
-        std::vector<float> ComputeMelSpec(const std::vector<int16_t>& audioData, float trainingMean = 0);
-
-        /**
-         * @brief       Constructor
-         * @param[in]   params   Mel Spectrogram parameters
-        */
-        explicit MelSpectrogram(const MelSpecParams& params);
-
-        MelSpectrogram() = delete;
-        ~MelSpectrogram() = default;
-
-        /** @brief  Initialise */
-        void Init();
-
-        /**
-         * @brief        Extract Mel Spectrogram 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.
-         * @param[in]    trainingMean   training mean.
-         * @return       Vector of extracted quantised Mel Spectrogram features.
-         **/
-        template<typename T>
-        std::vector<T> MelSpecComputeQuant(const std::vector<int16_t>& audioData,
-                                           const float quantScale,
-                                           const int quantOffset,
-                                           float trainingMean = 0)
-        {
-            this->ComputeMelSpec(audioData, trainingMean);
-            float minVal = std::numeric_limits<T>::min();
-            float maxVal = std::numeric_limits<T>::max();
-
-            std::vector<T> melSpecOut(this->m_params.m_numFbankBins);
-            const size_t numFbankBins = this->m_params.m_numFbankBins;
-
-            /* Quantize to T. */
-            for (size_t k = 0; k < numFbankBins; ++k) {
-                auto quantizedEnergy = std::round(((this->m_melEnergies[k]) / quantScale) + quantOffset);
-                melSpecOut[k] = static_cast<T>(std::min<float>(std::max<float>(quantizedEnergy, minVal), maxVal));
-            }
-
-            return melSpecOut;
-        }
-
-        /* 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(const float    freq,
-                              const 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(const float melFreq,
-                                     const 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       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      Return float value to be applied 
-         *              when populating the filter bank.
-         */
-        virtual float GetMelFilterBankNormaliser(
-                const float&   leftMel,
-                const float&   rightMel,
-                const bool     useHTKMethod);
-
-    private:
-        MelSpecParams                   m_params;
-        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<uint32_t>            m_filterBankFilterFirst;
-        std::vector<uint32_t>            m_filterBankFilterLast;
-        bool                            m_filterBankInitialised;
-        arm::app::math::FftInstance     m_fftInstance;
-
-        /**
-         * @brief       Initialises the filter banks.
-         **/
-        void InitMelFilterBank();
-
-        /**
-         * @brief       Signals whether the instance of MelSpectrogram has had its
-         *              required buffers initialised
-         * @return      True if initialised, false otherwise
-         **/
-        bool IsMelFilterBankInited() const;
-
-        /**
-         * @brief       Create mel filter banks for Mel Spectrogram calculation.
-         * @return      2D vector of floats
-         **/
-        std::vector<std::vector<float>> CreateMelFilterBank();
-
-        /**
-         * @brief       Computes the magnitude from an interleaved complex array
-         **/
-        void ConvertToPowerSpectrum();
-
-    };
-
-} /* namespace audio */
-} /* namespace app */
-} /* namespace arm */
-
-
-#endif /* MELSPECTROGRAM_HPP */