Opensource ML embedded evaluation kit
Change-Id: I12e807f19f5cacad7cef82572b6dd48252fd61fd
diff --git a/source/use_case/kws_asr/include/Wav2LetterMfcc.hpp b/source/use_case/kws_asr/include/Wav2LetterMfcc.hpp
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+++ b/source/use_case/kws_asr/include/Wav2LetterMfcc.hpp
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+/*
+ * 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 KWS_ASR_WAV2LET_MFCC_HPP
+#define KWS_ASR_WAV2LET_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<int32_t>& filterBankFilterFirst,
+ std::vector<int32_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 /* KWS_ASR_WAV2LET_MFCC_HPP */