1 /* 2 * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 // Modified from the Chromium original here: 12 // src/media/base/sinc_resampler_unittest.cc 13 14 #ifndef COMMON_AUDIO_RESAMPLER_SINUSOIDAL_LINEAR_CHIRP_SOURCE_H_ 15 #define COMMON_AUDIO_RESAMPLER_SINUSOIDAL_LINEAR_CHIRP_SOURCE_H_ 16 17 #include "common_audio/resampler/sinc_resampler.h" 18 19 namespace webrtc { 20 21 // Fake audio source for testing the resampler. Generates a sinusoidal linear 22 // chirp (http://en.wikipedia.org/wiki/Chirp) which can be tuned to stress the 23 // resampler for the specific sample rate conversion being used. 24 class SinusoidalLinearChirpSource : public SincResamplerCallback { 25 public: 26 // `delay_samples` can be used to insert a fractional sample delay into the 27 // source. It will produce zeros until non-negative time is reached. 28 SinusoidalLinearChirpSource(int sample_rate, 29 size_t samples, 30 double max_frequency, 31 double delay_samples); 32 ~SinusoidalLinearChirpSource()33 ~SinusoidalLinearChirpSource() override {} 34 35 SinusoidalLinearChirpSource(const SinusoidalLinearChirpSource&) = delete; 36 SinusoidalLinearChirpSource& operator=(const SinusoidalLinearChirpSource&) = 37 delete; 38 39 void Run(size_t frames, float* destination) override; 40 41 double Frequency(size_t position); 42 43 private: 44 static constexpr int kMinFrequency = 5; 45 46 int sample_rate_; 47 size_t total_samples_; 48 double max_frequency_; 49 double k_; 50 size_t current_index_; 51 double delay_samples_; 52 }; 53 54 } // namespace webrtc 55 56 #endif // COMMON_AUDIO_RESAMPLER_SINUSOIDAL_LINEAR_CHIRP_SOURCE_H_ 57