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* Copyright (c) 2013 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.
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include "rtc_base/gtest_prod_util.h"
namespace webrtc {
class TransientDetector;
// Detects transients in an audio stream and suppress them using a simple
// restoration algorithm that attenuates unexpected spikes in the spectrum.
class TransientSuppressor {
int Initialize(int sample_rate_hz, int detector_rate_hz, int num_channels);
// Processes a |data| chunk, and returns it with keystrokes suppressed from
// it. The float format is assumed to be int16 ranged. If there are more than
// one channel, the chunks are concatenated one after the other in |data|.
// |data_length| must be equal to |data_length_|.
// |num_channels| must be equal to |num_channels_|.
// A sub-band, ideally the higher, can be used as |detection_data|. If it is
// NULL, |data| is used for the detection too. The |detection_data| is always
// assumed mono.
// If a reference signal (e.g. keyboard microphone) is available, it can be
// passed in as |reference_data|. It is assumed mono and must have the same
// length as |data|. NULL is accepted if unavailable.
// This suppressor performs better if voice information is available.
// |voice_probability| is the probability of voice being present in this chunk
// of audio. If voice information is not available, |voice_probability| must
// always be set to 1.
// |key_pressed| determines if a key was pressed on this audio chunk.
// Returns 0 on success and -1 otherwise.
int Suppress(float* data,
size_t data_length,
int num_channels,
const float* detection_data,
size_t detection_length,
const float* reference_data,
size_t reference_length,
float voice_probability,
bool key_pressed);
void Suppress(float* in_ptr, float* spectral_mean, float* out_ptr);
void UpdateKeypress(bool key_pressed);
void UpdateRestoration(float voice_probability);
void UpdateBuffers(float* data);
void HardRestoration(float* spectral_mean);
void SoftRestoration(float* spectral_mean);
std::unique_ptr<TransientDetector> detector_;
size_t data_length_;
size_t detection_length_;
size_t analysis_length_;
size_t buffer_delay_;
size_t complex_analysis_length_;
int num_channels_;
// Input buffer where the original samples are stored.
std::unique_ptr<float[]> in_buffer_;
std::unique_ptr<float[]> detection_buffer_;
// Output buffer where the restored samples are stored.
std::unique_ptr<float[]> out_buffer_;
// Arrays for fft.
std::unique_ptr<size_t[]> ip_;
std::unique_ptr<float[]> wfft_;
std::unique_ptr<float[]> spectral_mean_;
// Stores the data for the fft.
std::unique_ptr<float[]> fft_buffer_;
std::unique_ptr<float[]> magnitudes_;
const float* window_;
std::unique_ptr<float[]> mean_factor_;
float detector_smoothed_;
int keypress_counter_;
int chunks_since_keypress_;
bool detection_enabled_;
bool suppression_enabled_;
bool use_hard_restoration_;
int chunks_since_voice_change_;
uint32_t seed_;
bool using_reference_;
} // namespace webrtc