| /* |
| * SPDX-FileCopyrightText: Copyright 2021-2022 Arm Limited and/or its affiliates <open-source-office@arm.com> |
| * 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 RNNOISE_FEATURE_PROCESSOR_HPP |
| #define RNNOISE_FEATURE_PROCESSOR_HPP |
| |
| #include "PlatformMath.hpp" |
| #include <cstdint> |
| #include <vector> |
| #include <array> |
| #include <tuple> |
| |
| namespace arm { |
| namespace app { |
| namespace rnn { |
| |
| using vec1D32F = std::vector<float>; |
| using vec2D32F = std::vector<vec1D32F>; |
| using arrHp = std::array<float, 2>; |
| using math::FftInstance; |
| using math::FftType; |
| |
| class FrameFeatures { |
| public: |
| bool m_silence{false}; /* If frame contains silence or not. */ |
| vec1D32F m_featuresVec{}; /* Calculated feature vector to feed to model. */ |
| vec1D32F m_fftX{}; /* Vector of floats arranged to represent complex numbers. */ |
| vec1D32F m_fftP{}; /* Vector of floats arranged to represent complex numbers. */ |
| vec1D32F m_Ex{}; /* Spectral band energy for audio x. */ |
| vec1D32F m_Ep{}; /* Spectral band energy for pitch p. */ |
| vec1D32F m_Exp{}; /* Correlated spectral energy between x and p. */ |
| }; |
| |
| /** |
| * @brief RNNoise pre and post processing class based on the 2018 paper from |
| * Jan-Marc Valin. Recommended reading: |
| * - https://jmvalin.ca/demo/rnnoise/ |
| * - https://arxiv.org/abs/1709.08243 |
| **/ |
| class RNNoiseFeatureProcessor { |
| /* Public interface */ |
| public: |
| RNNoiseFeatureProcessor(); |
| ~RNNoiseFeatureProcessor() = default; |
| |
| /** |
| * @brief Calculates the features from a given audio buffer ready to be sent to RNNoise model. |
| * @param[in] audioData Pointer to the floating point vector |
| * with audio data (within the numerical |
| * limits of int16_t type). |
| * @param[in] audioLen Number of elements in the audio window. |
| * @param[out] features FrameFeatures object reference. |
| **/ |
| void PreprocessFrame(const float* audioData, |
| size_t audioLen, |
| FrameFeatures& features); |
| |
| /** |
| * @brief Use the RNNoise model output gain values with pre-processing features |
| * to generate audio with noise suppressed. |
| * @param[in] modelOutput Output gain values from model. |
| * @param[in] features Calculated features from pre-processing step. |
| * @param[out] outFrame Output frame to be populated. |
| **/ |
| void PostProcessFrame(vec1D32F& modelOutput, FrameFeatures& features, vec1D32F& outFrame); |
| |
| |
| /* Public constants */ |
| public: |
| static constexpr uint32_t FRAME_SIZE_SHIFT{2}; |
| static constexpr uint32_t FRAME_SIZE{512}; |
| static constexpr uint32_t WINDOW_SIZE{2 * FRAME_SIZE}; |
| static constexpr uint32_t FREQ_SIZE{FRAME_SIZE + 1}; |
| |
| static constexpr uint32_t PITCH_MIN_PERIOD{64}; |
| static constexpr uint32_t PITCH_MAX_PERIOD{820}; |
| static constexpr uint32_t PITCH_FRAME_SIZE{1024}; |
| static constexpr uint32_t PITCH_BUF_SIZE{PITCH_MAX_PERIOD + PITCH_FRAME_SIZE}; |
| |
| static constexpr uint32_t NB_BANDS{22}; |
| static constexpr uint32_t CEPS_MEM{8}; |
| static constexpr uint32_t NB_DELTA_CEPS{6}; |
| |
| static constexpr uint32_t NB_FEATURES{NB_BANDS + 3*NB_DELTA_CEPS + 2}; |
| |
| /* Private functions */ |
| private: |
| |
| /** |
| * @brief Initialises the half window and DCT tables. |
| */ |
| void InitTables(); |
| |
| /** |
| * @brief Applies a bi-quadratic filter over the audio window. |
| * @param[in] bHp Constant coefficient set b (arrHp type). |
| * @param[in] aHp Constant coefficient set a (arrHp type). |
| * @param[in,out] memHpX Coefficients populated by this function. |
| * @param[in,out] audioWindow Floating point vector with audio data. |
| **/ |
| void BiQuad( |
| const arrHp& bHp, |
| const arrHp& aHp, |
| arrHp& memHpX, |
| vec1D32F& audioWindow); |
| |
| /** |
| * @brief Computes features from the "filtered" audio window. |
| * @param[in] audioWindow Floating point vector with audio data. |
| * @param[out] features FrameFeatures object reference. |
| **/ |
| void ComputeFrameFeatures(vec1D32F& audioWindow, FrameFeatures& features); |
| |
| /** |
| * @brief Runs analysis on the audio buffer. |
| * @param[in] audioWindow Floating point vector with audio data. |
| * @param[out] fft Floating point FFT vector containing real and |
| * imaginary pairs of elements. NOTE: this vector |
| * does not contain the mirror image (conjugates) |
| * part of the spectrum. |
| * @param[out] energy Computed energy for each band in the Bark scale. |
| * @param[out] analysisMem Buffer sequentially, but partially, |
| * populated with new audio data. |
| **/ |
| void FrameAnalysis( |
| const vec1D32F& audioWindow, |
| vec1D32F& fft, |
| vec1D32F& energy, |
| vec1D32F& analysisMem); |
| |
| /** |
| * @brief Applies the window function, in-place, over the given |
| * floating point buffer. |
| * @param[in,out] x Buffer the window will be applied to. |
| **/ |
| void ApplyWindow(vec1D32F& x); |
| |
| /** |
| * @brief Computes the FFT for a given vector. |
| * @param[in] x Vector to compute the FFT from. |
| * @param[out] fft Floating point FFT vector containing real and |
| * imaginary pairs of elements. NOTE: this vector |
| * does not contain the mirror image (conjugates) |
| * part of the spectrum. |
| **/ |
| void ForwardTransform( |
| vec1D32F& x, |
| vec1D32F& fft); |
| |
| /** |
| * @brief Computes band energy for each of the 22 Bark scale bands. |
| * @param[in] fft_X FFT spectrum (as computed by ForwardTransform). |
| * @param[out] bandE Vector with 22 elements populated with energy for |
| * each band. |
| **/ |
| void ComputeBandEnergy(const vec1D32F& fft_X, vec1D32F& bandE); |
| |
| /** |
| * @brief Computes band energy correlation. |
| * @param[in] X FFT vector X. |
| * @param[in] P FFT vector P. |
| * @param[out] bandC Vector with 22 elements populated with band energy |
| * correlation for the two input FFT vectors. |
| **/ |
| void ComputeBandCorr(const vec1D32F& X, const vec1D32F& P, vec1D32F& bandC); |
| |
| /** |
| * @brief Performs pitch auto-correlation for a given vector for |
| * given lag. |
| * @param[in] x Input vector. |
| * @param[out] ac Auto-correlation output vector. |
| * @param[in] lag Lag value. |
| * @param[in] n Number of elements to consider for correlation |
| * computation. |
| **/ |
| void AutoCorr(const vec1D32F &x, |
| vec1D32F &ac, |
| size_t lag, |
| size_t n); |
| |
| /** |
| * @brief Computes pitch cross-correlation. |
| * @param[in] x Input vector 1. |
| * @param[in] y Input vector 2. |
| * @param[out] xCorr Cross-correlation output vector. |
| * @param[in] len Number of elements to consider for correlation. |
| * computation. |
| * @param[in] maxPitch Maximum pitch. |
| **/ |
| void PitchXCorr( |
| const vec1D32F& x, |
| const vec1D32F& y, |
| vec1D32F& xCorr, |
| size_t len, |
| size_t maxPitch); |
| |
| /** |
| * @brief Computes "Linear Predictor Coefficients". |
| * @param[in] ac Correlation vector. |
| * @param[in] p Number of elements of input vector to consider. |
| * @param[out] lpc Output coefficients vector. |
| **/ |
| void LPC(const vec1D32F& ac, int32_t p, vec1D32F& lpc); |
| |
| /** |
| * @brief Custom FIR implementation. |
| * @param[in] num FIR coefficient vector. |
| * @param[in] N Number of elements. |
| * @param[out] x Vector to be be processed. |
| **/ |
| void Fir5(const vec1D32F& num, uint32_t N, vec1D32F& x); |
| |
| /** |
| * @brief Down-sample the pitch buffer. |
| * @param[in,out] pitchBuf Pitch buffer. |
| * @param[in] pitchBufSz Buffer size. |
| **/ |
| void PitchDownsample(vec1D32F& pitchBuf, size_t pitchBufSz); |
| |
| /** |
| * @brief Pitch search function. |
| * @param[in] xLP Shifted pitch buffer input. |
| * @param[in] y Pitch buffer input. |
| * @param[in] len Length to search for. |
| * @param[in] maxPitch Maximum pitch. |
| * @return pitch index. |
| **/ |
| int PitchSearch(vec1D32F& xLp, vec1D32F& y, uint32_t len, uint32_t maxPitch); |
| |
| /** |
| * @brief Finds the "best" pitch from the buffer. |
| * @param[in] xCorr Pitch correlation vector. |
| * @param[in] y Pitch buffer input. |
| * @param[in] len Length to search for. |
| * @param[in] maxPitch Maximum pitch. |
| * @return pitch array (2 elements). |
| **/ |
| arrHp FindBestPitch(vec1D32F& xCorr, vec1D32F& y, uint32_t len, uint32_t maxPitch); |
| |
| /** |
| * @brief Remove pitch period doubling errors. |
| * @param[in,out] pitchBuf Pitch buffer vector. |
| * @param[in] maxPeriod Maximum period. |
| * @param[in] minPeriod Minimum period. |
| * @param[in] frameSize Frame size. |
| * @param[in] pitchIdx0_ Pitch index 0. |
| * @return pitch index. |
| **/ |
| int RemoveDoubling( |
| vec1D32F& pitchBuf, |
| uint32_t maxPeriod, |
| uint32_t minPeriod, |
| uint32_t frameSize, |
| size_t pitchIdx0_); |
| |
| /** |
| * @brief Computes pitch gain. |
| * @param[in] xy Single xy cross correlation value. |
| * @param[in] xx Single xx auto correlation value. |
| * @param[in] yy Single yy auto correlation value. |
| * @return Calculated pitch gain. |
| **/ |
| float ComputePitchGain(float xy, float xx, float yy); |
| |
| /** |
| * @brief Computes DCT vector from the given input. |
| * @param[in] input Input vector. |
| * @param[out] output Output vector with DCT coefficients. |
| **/ |
| void DCT(vec1D32F& input, vec1D32F& output); |
| |
| /** |
| * @brief Perform inverse fourier transform on complex spectral vector. |
| * @param[out] out Output vector. |
| * @param[in] fftXIn Vector of floats arranged to represent complex numbers interleaved. |
| **/ |
| void InverseTransform(vec1D32F& out, vec1D32F& fftXIn); |
| |
| /** |
| * @brief Perform pitch filtering. |
| * @param[in] features Object with pre-processing calculated frame features. |
| * @param[in] g Gain values. |
| **/ |
| void PitchFilter(FrameFeatures& features, vec1D32F& g); |
| |
| /** |
| * @brief Interpolate the band gain values. |
| * @param[out] g Gain values. |
| * @param[in] bandE Vector with 22 elements populated with energy for |
| * each band. |
| **/ |
| void InterpBandGain(vec1D32F& g, vec1D32F& bandE); |
| |
| /** |
| * @brief Create de-noised frame. |
| * @param[out] outFrame Output vector for storing the created audio frame. |
| * @param[in] fftY Gain adjusted complex spectral vector. |
| */ |
| void FrameSynthesis(vec1D32F& outFrame, vec1D32F& fftY); |
| |
| /* Private objects */ |
| private: |
| FftInstance m_fftInstReal; /* FFT instance for real numbers */ |
| FftInstance m_fftInstCmplx; /* FFT instance for complex numbers */ |
| vec1D32F m_halfWindow; /* Window coefficients */ |
| vec1D32F m_dctTable; /* DCT table */ |
| vec1D32F m_analysisMem; /* Buffer used for frame analysis */ |
| vec2D32F m_cepstralMem; /* Cepstral coefficients */ |
| size_t m_memId; /* memory ID */ |
| vec1D32F m_synthesisMem; /* Synthesis mem (used by post-processing) */ |
| vec1D32F m_pitchBuf; /* Pitch buffer */ |
| float m_lastGain; /* Last gain calculated */ |
| int m_lastPeriod; /* Last period calculated */ |
| arrHp m_memHpX; /* HpX coefficients. */ |
| vec1D32F m_lastGVec; /* Last gain vector (used by post-processing) */ |
| |
| /* Constants */ |
| const std::array <uint32_t, NB_BANDS> m_eband5ms { |
| 0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, |
| 14, 16, 20, 24, 28, 34, 40, 48, 60, 78, 100}; |
| }; |
| |
| |
| } /* namespace rnn */ |
| } /* namespace app */ |
| } /* namespace arm */ |
| |
| #endif /* RNNOISE_FEATURE_PROCESSOR_HPP */ |