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diff --git a/source/use_case/asr/src/Wav2LetterMfcc.cc b/source/use_case/asr/src/Wav2LetterMfcc.cc
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+++ b/source/use_case/asr/src/Wav2LetterMfcc.cc
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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.
+ */
+#include "Wav2LetterMfcc.hpp"
+
+#include "PlatformMath.hpp"
+
+#include <cfloat>
+
+namespace arm {
+namespace app {
+namespace audio {
+
+    bool Wav2LetterMFCC::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)
+    {
+        const size_t numBanks = melEnergies.size();
+
+        if (numBanks != filterBankFilterFirst.size() ||
+                numBanks != filterBankFilterLast.size()) {
+            printf_err("Unexpected filter bank lengths\n");
+            return false;
+        }
+
+        for (size_t bin = 0; bin < numBanks; ++bin) {
+            auto filterBankIter = melFilterBank[bin].begin();
+            float melEnergy = 1e-10;  /* Avoid log of zero at later stages, same value used in librosa. */
+            const int32_t firstIndex = filterBankFilterFirst[bin];
+            const int32_t lastIndex = filterBankFilterLast[bin];
+
+            for (int32_t i = firstIndex; i <= lastIndex; ++i) {
+                melEnergy += (*filterBankIter++ * fftVec[i]);
+            }
+
+            melEnergies[bin] = melEnergy;
+        }
+
+        return true;
+    }
+
+    void Wav2LetterMFCC::ConvertToLogarithmicScale(
+                            std::vector<float>& melEnergies)
+    {
+        float maxMelEnergy = -FLT_MAX;
+
+        /* Container for natural logarithms of mel energies. */
+        std::vector <float> vecLogEnergies(melEnergies.size(), 0.f);
+
+        /* Because we are taking natural logs, we need to multiply by log10(e).
+         * Also, for wav2letter model, we scale our log10 values by 10. */
+        constexpr float multiplier = 10.0 *  /* Default scalar. */
+                                      0.4342944819032518;  /* log10f(std::exp(1.0)) */
+
+        /* Take log of the whole vector. */
+        math::MathUtils::VecLogarithmF32(melEnergies, vecLogEnergies);
+
+        /* Scale the log values and get the max. */
+        for (auto iterM = melEnergies.begin(), iterL = vecLogEnergies.begin();
+                  iterM != melEnergies.end(); ++iterM, ++iterL) {
+
+            *iterM = *iterL * multiplier;
+
+            /* Save the max mel energy. */
+            if (*iterM > maxMelEnergy) {
+                maxMelEnergy = *iterM;
+            }
+        }
+
+        /* Clamp the mel energies. */
+        constexpr float maxDb = 80.0;
+        const float clampLevelLowdB = maxMelEnergy - maxDb;
+        for (auto iter = melEnergies.begin(); iter != melEnergies.end(); ++iter) {
+            *iter = std::max(*iter, clampLevelLowdB);
+        }
+    }
+
+    std::vector<float> Wav2LetterMFCC::CreateDCTMatrix(
+                                        const int32_t inputLength,
+                                        const int32_t coefficientCount)
+    {
+        std::vector<float> dctMatix(inputLength * coefficientCount);
+
+        /* Orthonormal normalization. */
+        const float normalizerK0 = 2 * math::MathUtils::SqrtF32(1.0f /
+                                        static_cast<float>(4*inputLength));
+        const float normalizer = 2 * math::MathUtils::SqrtF32(1.0f /
+                                        static_cast<float>(2*inputLength));
+
+        const float angleIncr = M_PI / inputLength;
+        float angle = angleIncr;  /* We start using it at k = 1 loop. */
+
+        /* First row of DCT will use normalizer K0. */
+        for (int32_t n = 0; n < inputLength; ++n) {
+            dctMatix[n] = normalizerK0  /* cos(0) = 1 */;
+        }
+
+        /* Second row (index = 1) onwards, we use standard normalizer. */
+        for (int32_t k = 1, m = inputLength; k < coefficientCount; ++k, m += inputLength) {
+            for (int32_t n = 0; n < inputLength; ++n) {
+                dctMatix[m+n] = normalizer *
+                    math::MathUtils::CosineF32((n + 0.5f) * angle);
+            }
+            angle += angleIncr;
+        }
+        return dctMatix;
+    }
+
+    float Wav2LetterMFCC::GetMelFilterBankNormaliser(
+                                    const float&    leftMel,
+                                    const float&    rightMel,
+                                    const bool      useHTKMethod)
+    {
+        /* Slaney normalization for mel weights. */
+        return (2.0f / (MFCC::InverseMelScale(rightMel, useHTKMethod) -
+                MFCC::InverseMelScale(leftMel, useHTKMethod)));
+    }
+
+} /* namespace audio */
+} /* namespace app */
+} /* namespace arm */