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* 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.
#include <stddef.h>
#include <stdint.h>
#include "modules/audio_coding/neteq/time_stretch.h"
#include "rtc_base/constructor_magic.h"
namespace webrtc {
class AudioMultiVector;
class BackgroundNoise;
// This class implements the Accelerate operation. Most of the work is done
// in the base class TimeStretch, which is shared with the PreemptiveExpand
// operation. In the Accelerate class, the operations that are specific to
// Accelerate are implemented.
class Accelerate : public TimeStretch {
Accelerate(int sample_rate_hz,
size_t num_channels,
const BackgroundNoise& background_noise)
: TimeStretch(sample_rate_hz, num_channels, background_noise) {}
// This method performs the actual Accelerate operation. The samples are
// read from |input|, of length |input_length| elements, and are written to
// |output|. The number of samples removed through time-stretching is
// is provided in the output |length_change_samples|. The method returns
// the outcome of the operation as an enumerator value. If |fast_accelerate|
// is true, the algorithm will relax the requirements on finding strong
// correlations, and may remove multiple pitch periods if possible.
ReturnCodes Process(const int16_t* input,
size_t input_length,
bool fast_accelerate,
AudioMultiVector* output,
size_t* length_change_samples);
// Sets the parameters |best_correlation| and |peak_index| to suitable
// values when the signal contains no active speech.
void SetParametersForPassiveSpeech(size_t len,
int16_t* best_correlation,
size_t* peak_index) const override;
// Checks the criteria for performing the time-stretching operation and,
// if possible, performs the time-stretching.
ReturnCodes CheckCriteriaAndStretch(const int16_t* input,
size_t input_length,
size_t peak_index,
int16_t best_correlation,
bool active_speech,
bool fast_mode,
AudioMultiVector* output) const override;
struct AccelerateFactory {
AccelerateFactory() {}
virtual ~AccelerateFactory() {}
virtual Accelerate* Create(int sample_rate_hz,
size_t num_channels,
const BackgroundNoise& background_noise) const;
} // namespace webrtc