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/*
* Copyright (c) 2014 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 WEBRTC_MODULES_AUDIO_PROCESSING_INTELLIGIBILITY_INTELLIGIBILITY_UTILS_H_
#define WEBRTC_MODULES_AUDIO_PROCESSING_INTELLIGIBILITY_INTELLIGIBILITY_UTILS_H_
#include <complex>
#include <memory>
namespace webrtc {
namespace intelligibility {
// Internal helper for computing the power of a stream of arrays.
// The result is an array of power per position: the i-th power is the power of
// the stream of data on the i-th positions in the input arrays.
class PowerEstimator {
public:
// Construct an instance for the given input array length (|freqs|), with the
// appropriate parameters. |decay| is the forgetting factor.
PowerEstimator(size_t freqs, float decay);
// Add a new data point to the series.
void Step(const std::complex<float>* data);
// The current power array.
const float* Power();
private:
// TODO(ekmeyerson): Switch the following running means
// and histories from std::unique_ptr to std::vector.
std::unique_ptr<std::complex<float>[]> running_mean_sq_;
// The current magnitude array.
std::unique_ptr<float[]> magnitude_;
// The current power array.
std::unique_ptr<float[]> power_;
const size_t num_freqs_;
const float decay_;
};
// Helper class for smoothing gain changes. On each application step, the
// currently used gains are changed towards a set of settable target gains,
// constrained by a limit on the magnitude of the changes.
class GainApplier {
public:
GainApplier(size_t freqs, float change_limit);
// Copy |in_block| to |out_block|, multiplied by the current set of gains,
// and step the current set of gains towards the target set.
void Apply(const std::complex<float>* in_block,
std::complex<float>* out_block);
// Return the current target gain set. Modify this array to set the targets.
float* target() const { return target_.get(); }
private:
const size_t num_freqs_;
const float change_limit_;
std::unique_ptr<float[]> target_;
std::unique_ptr<float[]> current_;
};
} // namespace intelligibility
} // namespace webrtc
#endif // WEBRTC_MODULES_AUDIO_PROCESSING_INTELLIGIBILITY_INTELLIGIBILITY_UTILS_H_