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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.
*/
// Modified from the Chromium original here:
// src/media/base/sinc_resampler_unittest.cc
#ifndef COMMON_AUDIO_RESAMPLER_SINUSOIDAL_LINEAR_CHIRP_SOURCE_H_
#define COMMON_AUDIO_RESAMPLER_SINUSOIDAL_LINEAR_CHIRP_SOURCE_H_
#include "common_audio/resampler/sinc_resampler.h"
namespace webrtc {
// Fake audio source for testing the resampler. Generates a sinusoidal linear
// chirp (http://en.wikipedia.org/wiki/Chirp) which can be tuned to stress the
// resampler for the specific sample rate conversion being used.
class SinusoidalLinearChirpSource : public SincResamplerCallback {
public:
// `delay_samples` can be used to insert a fractional sample delay into the
// source. It will produce zeros until non-negative time is reached.
SinusoidalLinearChirpSource(int sample_rate,
size_t samples,
double max_frequency,
double delay_samples);
~SinusoidalLinearChirpSource() override {}
SinusoidalLinearChirpSource(const SinusoidalLinearChirpSource&) = delete;
SinusoidalLinearChirpSource& operator=(const SinusoidalLinearChirpSource&) =
delete;
void Run(size_t frames, float* destination) override;
double Frequency(size_t position);
private:
static constexpr int kMinFrequency = 5;
int sample_rate_;
size_t total_samples_;
double max_frequency_;
double k_;
size_t current_index_;
double delay_samples_;
};
} // namespace webrtc
#endif // COMMON_AUDIO_RESAMPLER_SINUSOIDAL_LINEAR_CHIRP_SOURCE_H_
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