/* * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ #ifndef MODULES_AUDIO_PROCESSING_VAD_VAD_AUDIO_PROC_H_ #define MODULES_AUDIO_PROCESSING_VAD_VAD_AUDIO_PROC_H_ #include #include #include #include "modules/audio_processing/vad/common.h" // AudioFeatures, kSampleR... namespace webrtc { class PoleZeroFilter; class VadAudioProc { public: // Forward declare iSAC structs. struct PitchAnalysisStruct; struct PreFiltBankstr; VadAudioProc(); ~VadAudioProc(); int ExtractFeatures(const int16_t* audio_frame, size_t length, AudioFeatures* audio_features); static constexpr size_t kDftSize = 512; private: void PitchAnalysis(double* pitch_gains, double* pitch_lags_hz, size_t length); void SubframeCorrelation(double* corr, size_t length_corr, size_t subframe_index); void GetLpcPolynomials(double* lpc, size_t length_lpc); void FindFirstSpectralPeaks(double* f_peak, size_t length_f_peak); void Rms(double* rms, size_t length_rms); void ResetBuffer(); // To compute spectral peak we perform LPC analysis to get spectral envelope. // For every 30 ms we compute 3 spectral peak there for 3 LPC analysis. // LPC is computed over 15 ms of windowed audio. For every 10 ms sub-frame // we need 5 ms of past signal to create the input of LPC analysis. static constexpr size_t kNumPastSignalSamples = size_t{kSampleRateHz / 200}; // TODO(turajs): maybe defining this at a higher level (maybe enum) so that // all the code recognize it as "no-error." static constexpr int kNoError = 0; static constexpr size_t kNum10msSubframes = 3; static constexpr size_t kNumSubframeSamples = size_t{kSampleRateHz / 100}; // Samples in 30 ms @ given sampling rate. static constexpr size_t kNumSamplesToProcess = kNum10msSubframes * kNumSubframeSamples; static constexpr size_t kBufferLength = kNumPastSignalSamples + kNumSamplesToProcess; static constexpr size_t kIpLength = kDftSize >> 1; static constexpr size_t kWLength = kDftSize >> 1; static constexpr size_t kLpcOrder = 16; size_t ip_[kIpLength]; float w_fft_[kWLength]; // A buffer of 5 ms (past audio) + 30 ms (one iSAC frame ). float audio_buffer_[kBufferLength]; size_t num_buffer_samples_; double log_old_gain_; double old_lag_; std::unique_ptr pitch_analysis_handle_; std::unique_ptr pre_filter_handle_; std::unique_ptr high_pass_filter_; }; } // namespace webrtc #endif // MODULES_AUDIO_PROCESSING_VAD_VAD_AUDIO_PROC_H_