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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 <vector>
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.
template <typename T>
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 T* data);
// The current power array.
const std::vector<float>& power() { return power_; };
private:
// The current power array.
std::vector<float> power_;
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 relative changes.
class GainApplier {
public:
GainApplier(size_t freqs, float relative_change_limit);
~GainApplier();
// 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() { return target_.data(); }
private:
const size_t num_freqs_;
const float relative_change_limit_;
std::vector<float> target_;
std::vector<float> current_;
};
// Helper class to delay a signal by an integer number of samples.
class DelayBuffer {
public:
DelayBuffer(size_t delay, size_t num_channels);
~DelayBuffer();
void Delay(float* const* data, size_t length);
private:
std::vector<std::vector<float>> buffer_;
size_t read_index_;
};
} // namespace intelligibility
} // namespace webrtc
#endif // WEBRTC_MODULES_AUDIO_PROCESSING_INTELLIGIBILITY_INTELLIGIBILITY_UTILS_H_
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