89 lines
2.9 KiB
C
89 lines
2.9 KiB
C
|
/*
|
||
|
|
* 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 <stddef.h>
|
||
|
|
#include <stdint.h>
|
||
|
|
|
||
|
|
#include <memory>
|
||
|
|
|
||
|
|
#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<PitchAnalysisStruct> pitch_analysis_handle_;
|
||
|
|
std::unique_ptr<PreFiltBankstr> pre_filter_handle_;
|
||
|
|
std::unique_ptr<PoleZeroFilter> high_pass_filter_;
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace webrtc
|
||
|
|
|
||
|
|
#endif // MODULES_AUDIO_PROCESSING_VAD_VAD_AUDIO_PROC_H_
|