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>
diff --git a/source/application/api/use_case/asr/include/AsrClassifier.hpp b/source/application/api/use_case/asr/include/AsrClassifier.hpp
new file mode 100644
index 0000000..a07a721
--- /dev/null
+++ b/source/application/api/use_case/asr/include/AsrClassifier.hpp
@@ -0,0 +1,63 @@
+/*
+ * 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 ASR_CLASSIFIER_HPP
+#define ASR_CLASSIFIER_HPP
+
+#include "Classifier.hpp"
+
+namespace arm {
+namespace app {
+
+ class AsrClassifier : public Classifier {
+ public:
+ /**
+ * @brief Gets the top N classification results from the
+ * output vector.
+ * @param[in] outputTensor Inference output tensor from an NN model.
+ * @param[out] vecResults A vector of classification results
+ * populated by this function.
+ * @param[in] labels Labels vector to match classified classes
+ * @param[in] topNCount Number of top classifications to pick.
+ * @param[in] use_softmax Whether softmax scaling should be applied to model output.
+ * @return true if successful, false otherwise.
+ **/
+ bool GetClassificationResults(TfLiteTensor* outputTensor,
+ std::vector<ClassificationResult>& vecResults,
+ const std::vector<std::string>& labels,
+ uint32_t topNCount, bool use_softmax = false) override;
+
+ private:
+ /**
+ * @brief Utility function that gets the top 1 classification results from the
+ * output tensor (vector of vector).
+ * @param[in] tensor Inference output tensor from an NN model.
+ * @param[out] vecResults Vector of classification results populated by this function.
+ * @param[in] labels Labels vector to match classified classes.
+ * @param[in] scale Quantization scale.
+ * @param[in] zeroPoint Quantization zero point.
+ * @return true if successful, false otherwise.
+ **/
+ template<typename T>
+ bool GetTopResults(TfLiteTensor* tensor,
+ std::vector<ClassificationResult>& vecResults,
+ const std::vector<std::string>& labels, double scale, double zeroPoint);
+ };
+
+} /* namespace app */
+} /* namespace arm */
+
+#endif /* ASR_CLASSIFIER_HPP */
\ No newline at end of file
diff --git a/source/application/api/use_case/asr/include/AsrResult.hpp b/source/application/api/use_case/asr/include/AsrResult.hpp
new file mode 100644
index 0000000..ed826d0
--- /dev/null
+++ b/source/application/api/use_case/asr/include/AsrResult.hpp
@@ -0,0 +1,63 @@
+/*
+ * 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 ASR_RESULT_HPP
+#define ASR_RESULT_HPP
+
+#include "ClassificationResult.hpp"
+
+#include <vector>
+
+namespace arm {
+namespace app {
+namespace asr {
+
+ using ResultVec = std::vector<arm::app::ClassificationResult>;
+
+ /* Structure for holding ASR result. */
+ class AsrResult {
+
+ public:
+ ResultVec m_resultVec; /* Container for "thresholded" classification results. */
+ float m_timeStamp; /* Audio timestamp for this result. */
+ uint32_t m_inferenceNumber; /* Corresponding inference number. */
+ float m_threshold; /* Threshold value for `m_resultVec.` */
+
+ AsrResult() = delete;
+ AsrResult(ResultVec& resultVec,
+ const float timestamp,
+ const uint32_t inferenceIdx,
+ const float scoreThreshold) {
+
+ this->m_threshold = scoreThreshold;
+ this->m_timeStamp = timestamp;
+ this->m_inferenceNumber = inferenceIdx;
+
+ this->m_resultVec = ResultVec();
+ for (auto& i : resultVec) {
+ if (i.m_normalisedVal >= this->m_threshold) {
+ this->m_resultVec.emplace_back(i);
+ }
+ }
+ }
+ ~AsrResult() = default;
+ };
+
+} /* namespace asr */
+} /* namespace app */
+} /* namespace arm */
+
+#endif /* ASR_RESULT_HPP */
\ No newline at end of file
diff --git a/source/application/api/use_case/asr/include/OutputDecode.hpp b/source/application/api/use_case/asr/include/OutputDecode.hpp
new file mode 100644
index 0000000..9d39057
--- /dev/null
+++ b/source/application/api/use_case/asr/include/OutputDecode.hpp
@@ -0,0 +1,40 @@
+/*
+ * 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 ASR_OUTPUT_DECODE_HPP
+#define ASR_OUTPUT_DECODE_HPP
+
+#include "AsrClassifier.hpp"
+
+namespace arm {
+namespace app {
+namespace audio {
+namespace asr {
+
+ /**
+ * @brief Gets the top N classification results from the
+ * output vector.
+ * @param[in] vecResults Label output from classifier.
+ * @return true if successful, false otherwise.
+ **/
+ std::string DecodeOutput(const std::vector<ClassificationResult>& vecResults);
+
+} /* namespace asr */
+} /* namespace audio */
+} /* namespace app */
+} /* namespace arm */
+
+#endif /* ASR_OUTPUT_DECODE_HPP */
\ No newline at end of file
diff --git a/source/application/api/use_case/asr/include/Wav2LetterMfcc.hpp b/source/application/api/use_case/asr/include/Wav2LetterMfcc.hpp
new file mode 100644
index 0000000..b5a21d3
--- /dev/null
+++ b/source/application/api/use_case/asr/include/Wav2LetterMfcc.hpp
@@ -0,0 +1,109 @@
+/*
+ * 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 ASR_WAV2LETTER_MFCC_HPP
+#define ASR_WAV2LETTER_MFCC_HPP
+
+#include "Mfcc.hpp"
+
+namespace arm {
+namespace app {
+namespace audio {
+
+ /* Class to provide Wav2Letter specific MFCC calculation requirements. */
+ class Wav2LetterMFCC : public MFCC {
+
+ public:
+ static constexpr uint32_t ms_defaultSamplingFreq = 16000;
+ static constexpr uint32_t ms_defaultNumFbankBins = 128;
+ static constexpr uint32_t ms_defaultMelLoFreq = 0;
+ static constexpr uint32_t ms_defaultMelHiFreq = 8000;
+ static constexpr bool ms_defaultUseHtkMethod = false;
+
+ explicit Wav2LetterMFCC(const size_t numFeats, const size_t frameLen)
+ : MFCC(MfccParams(
+ ms_defaultSamplingFreq, ms_defaultNumFbankBins,
+ ms_defaultMelLoFreq, ms_defaultMelHiFreq,
+ numFeats, frameLen, ms_defaultUseHtkMethod))
+ {}
+
+ Wav2LetterMFCC() = delete;
+ ~Wav2LetterMFCC() = 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
+ */
+ 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
+ **/
+ void ConvertToLogarithmicScale(std::vector<float>& melEnergies) override;
+
+ /**
+ * @brief Create a matrix used to calculate Discrete Cosine
+ * Transform. Override for the base class' default
+ * implementation as the first and last elements
+ * use a different normaliser.
+ * @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.
+ */
+ std::vector<float> CreateDCTMatrix(int32_t inputLength,
+ int32_t coefficientCount) 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 Value to use for normalising.
+ */
+ float GetMelFilterBankNormaliser(const float& leftMel,
+ const float& rightMel,
+ bool useHTKMethod) override;
+ };
+
+} /* namespace audio */
+} /* namespace app */
+} /* namespace arm */
+
+#endif /* ASR_WAV2LETTER_MFCC_HPP */
\ No newline at end of file
diff --git a/source/application/api/use_case/asr/include/Wav2LetterModel.hpp b/source/application/api/use_case/asr/include/Wav2LetterModel.hpp
new file mode 100644
index 0000000..a02eed1
--- /dev/null
+++ b/source/application/api/use_case/asr/include/Wav2LetterModel.hpp
@@ -0,0 +1,67 @@
+/*
+ * 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 ASR_WAV2LETTER_MODEL_HPP
+#define ASR_WAV2LETTER_MODEL_HPP
+
+#include "Model.hpp"
+
+namespace arm {
+namespace app {
+namespace asr {
+ extern const int g_FrameLength;
+ extern const int g_FrameStride;
+ extern const float g_ScoreThreshold;
+ extern const int g_ctxLen;
+} /* namespace asr */
+} /* namespace app */
+} /* namespace arm */
+
+namespace arm {
+namespace app {
+
+ class Wav2LetterModel : public Model {
+
+ public:
+ /* Indices for the expected model - based on input and output tensor shapes */
+ static constexpr uint32_t ms_inputRowsIdx = 1;
+ static constexpr uint32_t ms_inputColsIdx = 2;
+ static constexpr uint32_t ms_outputRowsIdx = 2;
+ static constexpr uint32_t ms_outputColsIdx = 3;
+
+ /* Model specific constants. */
+ static constexpr uint32_t ms_blankTokenIdx = 28;
+ static constexpr uint32_t ms_numMfccFeatures = 13;
+
+ 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;
+
+ private:
+ /* Maximum number of individual operations that can be enlisted. */
+ static constexpr int ms_maxOpCnt = 5;
+
+ /* A mutable op resolver instance. */
+ tflite::MicroMutableOpResolver<ms_maxOpCnt> m_opResolver;
+ };
+
+} /* namespace app */
+} /* namespace arm */
+
+#endif /* ASR_WAV2LETTER_MODEL_HPP */
diff --git a/source/application/api/use_case/asr/include/Wav2LetterPostprocess.hpp b/source/application/api/use_case/asr/include/Wav2LetterPostprocess.hpp
new file mode 100644
index 0000000..02738bc
--- /dev/null
+++ b/source/application/api/use_case/asr/include/Wav2LetterPostprocess.hpp
@@ -0,0 +1,109 @@
+/*
+ * 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 ASR_WAV2LETTER_POSTPROCESS_HPP
+#define ASR_WAV2LETTER_POSTPROCESS_HPP
+
+#include "TensorFlowLiteMicro.hpp" /* TensorFlow headers. */
+#include "BaseProcessing.hpp"
+#include "Model.hpp"
+#include "AsrClassifier.hpp"
+#include "AsrResult.hpp"
+#include "log_macros.h"
+
+namespace arm {
+namespace app {
+
+ /**
+ * @brief Helper class to manage tensor post-processing for "wav2letter"
+ * output.
+ */
+ class AsrPostProcess : public BasePostProcess {
+ public:
+ bool m_lastIteration = false; /* Flag to set if processing the last set of data for a clip. */
+
+ /**
+ * @brief Constructor
+ * @param[in] outputTensor Pointer to the TFLite Micro output Tensor.
+ * @param[in] classifier Object used to get top N results from classification.
+ * @param[in] labels Vector of string labels to identify each output of the model.
+ * @param[in/out] result Vector of classification results to store decoded outputs.
+ * @param[in] outputContextLen Left/right context length for output tensor.
+ * @param[in] blankTokenIdx Index in the labels that the "Blank token" takes.
+ * @param[in] reductionAxis The axis that the logits of each time step is on.
+ **/
+ AsrPostProcess(TfLiteTensor* outputTensor, AsrClassifier& classifier,
+ const std::vector<std::string>& labels, asr::ResultVec& result,
+ uint32_t outputContextLen,
+ uint32_t blankTokenIdx, uint32_t reductionAxis);
+
+ /**
+ * @brief Should perform post-processing of the result of inference then
+ * populate ASR result data for any later use.
+ * @return true if successful, false otherwise.
+ **/
+ bool DoPostProcess() override;
+
+ /** @brief Gets the output inner length for post-processing. */
+ static uint32_t GetOutputInnerLen(const TfLiteTensor*, uint32_t outputCtxLen);
+
+ /** @brief Gets the output context length (left/right) for post-processing. */
+ static uint32_t GetOutputContextLen(const Model& model, uint32_t inputCtxLen);
+
+ /** @brief Gets the number of feature vectors to be computed. */
+ static uint32_t GetNumFeatureVectors(const Model& model);
+
+ private:
+ AsrClassifier& m_classifier; /* ASR Classifier object. */
+ TfLiteTensor* m_outputTensor; /* Model output tensor. */
+ const std::vector<std::string>& m_labels; /* ASR Labels. */
+ asr::ResultVec & m_results; /* Results vector for a single inference. */
+ uint32_t m_outputContextLen; /* lengths of left/right contexts for output. */
+ uint32_t m_outputInnerLen; /* Length of output inner context. */
+ uint32_t m_totalLen; /* Total length of the required axis. */
+ uint32_t m_countIterations; /* Current number of iterations. */
+ uint32_t m_blankTokenIdx; /* Index of the labels blank token. */
+ uint32_t m_reductionAxisIdx; /* Axis containing output logits for a single step. */
+
+ /**
+ * @brief Checks if the tensor and axis index are valid
+ * inputs to the object - based on how it has been initialised.
+ * @return true if valid, false otherwise.
+ */
+ bool IsInputValid(TfLiteTensor* tensor,
+ uint32_t axisIdx) const;
+
+ /**
+ * @brief Gets the tensor data element size in bytes based
+ * on the tensor type.
+ * @return Size in bytes, 0 if not supported.
+ */
+ static uint32_t GetTensorElementSize(TfLiteTensor* tensor);
+
+ /**
+ * @brief Erases sections from the data assuming row-wise
+ * arrangement along the context axis.
+ * @return true if successful, false otherwise.
+ */
+ bool EraseSectionsRowWise(uint8_t* ptrData,
+ uint32_t strideSzBytes,
+ bool lastIteration);
+ };
+
+} /* namespace app */
+} /* namespace arm */
+
+#endif /* ASR_WAV2LETTER_POSTPROCESS_HPP */
\ No newline at end of file
diff --git a/source/application/api/use_case/asr/include/Wav2LetterPreprocess.hpp b/source/application/api/use_case/asr/include/Wav2LetterPreprocess.hpp
new file mode 100644
index 0000000..9943946
--- /dev/null
+++ b/source/application/api/use_case/asr/include/Wav2LetterPreprocess.hpp
@@ -0,0 +1,182 @@
+/*
+ * 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 ASR_WAV2LETTER_PREPROCESS_HPP
+#define ASR_WAV2LETTER_PREPROCESS_HPP
+
+#include "TensorFlowLiteMicro.hpp"
+#include "Wav2LetterMfcc.hpp"
+#include "AudioUtils.hpp"
+#include "DataStructures.hpp"
+#include "BaseProcessing.hpp"
+#include "log_macros.h"
+
+namespace arm {
+namespace app {
+
+ /* Class to facilitate pre-processing calculation for Wav2Letter model
+ * for ASR. */
+ using AudioWindow = audio::SlidingWindow<const int16_t>;
+
+ class AsrPreProcess : public BasePreProcess {
+ public:
+ /**
+ * @brief Constructor.
+ * @param[in] inputTensor Pointer to the TFLite Micro input Tensor.
+ * @param[in] numMfccFeatures Number of MFCC features per window.
+ * @param[in] numFeatureFrames Number of MFCC vectors that need to be calculated
+ * for an inference.
+ * @param[in] mfccWindowLen Number of audio elements to calculate MFCC features per window.
+ * @param[in] mfccWindowStride Stride (in number of elements) for moving the MFCC window.
+ */
+ AsrPreProcess(TfLiteTensor* inputTensor,
+ uint32_t numMfccFeatures,
+ uint32_t numFeatureFrames,
+ uint32_t mfccWindowLen,
+ uint32_t mfccWindowStride);
+
+ /**
+ * @brief Calculates the features required from audio data. This
+ * includes MFCC, first and second order deltas,
+ * normalisation and finally, quantisation. The tensor is
+ * populated with features from a given window placed along
+ * in a single row.
+ * @param[in] audioData Pointer to the first element of audio data.
+ * @param[in] audioDataLen Number of elements in the audio data.
+ * @return true if successful, false in case of error.
+ */
+ bool DoPreProcess(const void* audioData, size_t audioDataLen) override;
+
+ protected:
+ /**
+ * @brief Computes the first and second order deltas for the
+ * MFCC buffers - they are assumed to be populated.
+ *
+ * @param[in] mfcc MFCC buffers.
+ * @param[out] delta1 Result of the first diff computation.
+ * @param[out] delta2 Result of the second diff computation.
+ * @return true if successful, false otherwise.
+ */
+ static bool ComputeDeltas(Array2d<float>& mfcc,
+ Array2d<float>& delta1,
+ Array2d<float>& delta2);
+
+ /**
+ * @brief Given a 2D vector of floats, rescale it to have mean of 0 and
+ * standard deviation of 1.
+ * @param[in,out] vec Vector of vector of floats.
+ */
+ static void StandardizeVecF32(Array2d<float>& vec);
+
+ /**
+ * @brief Standardizes all the MFCC and delta buffers to have mean 0 and std. dev 1.
+ */
+ void Standarize();
+
+ /**
+ * @brief Given the quantisation and data type limits, computes
+ * the quantised values of a floating point input data.
+ * @param[in] elem Element to be quantised.
+ * @param[in] quantScale Scale.
+ * @param[in] quantOffset Offset.
+ * @param[in] minVal Numerical limit - minimum.
+ * @param[in] maxVal Numerical limit - maximum.
+ * @return Floating point quantised value.
+ */
+ static float GetQuantElem(
+ float elem,
+ float quantScale,
+ int quantOffset,
+ float minVal,
+ float maxVal);
+
+ /**
+ * @brief Quantises the MFCC and delta buffers, and places them
+ * in the output buffer. While doing so, it transposes
+ * the data. Reason: Buffers in this class are arranged
+ * for "time" axis to be row major. Primary reason for
+ * this being the convolution speed up (as we can use
+ * contiguous memory). The output, however, requires the
+ * time axis to be in column major arrangement.
+ * @param[in] outputBuf Pointer to the output buffer.
+ * @param[in] outputBufSz Output buffer's size.
+ * @param[in] quantScale Quantisation scale.
+ * @param[in] quantOffset Quantisation offset.
+ */
+ template <typename T>
+ bool Quantise(
+ T* outputBuf,
+ const uint32_t outputBufSz,
+ const float quantScale,
+ const int quantOffset)
+ {
+ /* Check the output size will fit everything. */
+ if (outputBufSz < (this->m_mfccBuf.size(0) * 3 * sizeof(T))) {
+ printf_err("Tensor size too small for features\n");
+ return false;
+ }
+
+ /* Populate. */
+ T* outputBufMfcc = outputBuf;
+ T* outputBufD1 = outputBuf + this->m_numMfccFeats;
+ T* outputBufD2 = outputBufD1 + this->m_numMfccFeats;
+ const uint32_t ptrIncr = this->m_numMfccFeats * 2; /* (3 vectors - 1 vector) */
+
+ const float minVal = std::numeric_limits<T>::min();
+ const float maxVal = std::numeric_limits<T>::max();
+
+ /* Need to transpose while copying and concatenating the tensor. */
+ for (uint32_t j = 0; j < this->m_numFeatureFrames; ++j) {
+ for (uint32_t i = 0; i < this->m_numMfccFeats; ++i) {
+ *outputBufMfcc++ = static_cast<T>(AsrPreProcess::GetQuantElem(
+ this->m_mfccBuf(i, j), quantScale,
+ quantOffset, minVal, maxVal));
+ *outputBufD1++ = static_cast<T>(AsrPreProcess::GetQuantElem(
+ this->m_delta1Buf(i, j), quantScale,
+ quantOffset, minVal, maxVal));
+ *outputBufD2++ = static_cast<T>(AsrPreProcess::GetQuantElem(
+ this->m_delta2Buf(i, j), quantScale,
+ quantOffset, minVal, maxVal));
+ }
+ outputBufMfcc += ptrIncr;
+ outputBufD1 += ptrIncr;
+ outputBufD2 += ptrIncr;
+ }
+
+ return true;
+ }
+
+ private:
+ audio::Wav2LetterMFCC m_mfcc; /* MFCC instance. */
+ TfLiteTensor* m_inputTensor; /* Model input tensor. */
+
+ /* Actual buffers to be populated. */
+ Array2d<float> m_mfccBuf; /* Contiguous buffer 1D: MFCC */
+ Array2d<float> m_delta1Buf; /* Contiguous buffer 1D: Delta 1 */
+ Array2d<float> m_delta2Buf; /* Contiguous buffer 1D: Delta 2 */
+
+ uint32_t m_mfccWindowLen; /* Window length for MFCC. */
+ uint32_t m_mfccWindowStride; /* Window stride len for MFCC. */
+ uint32_t m_numMfccFeats; /* Number of MFCC features per window. */
+ uint32_t m_numFeatureFrames; /* How many sets of m_numMfccFeats. */
+ AudioWindow m_mfccSlidingWindow; /* Sliding window to calculate MFCCs. */
+
+ };
+
+} /* namespace app */
+} /* namespace arm */
+
+#endif /* ASR_WAV2LETTER_PREPROCESS_HPP */
\ No newline at end of file