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 WEBRTC_COMMON_AUDIO_RESAMPLER_SINUSOIDAL_LINEAR_CHIRP_SOURCE_H_ 15 #define WEBRTC_COMMON_AUDIO_RESAMPLER_SINUSOIDAL_LINEAR_CHIRP_SOURCE_H_ 16 17 #include "webrtc/base/constructormagic.h" 18 #include "webrtc/common_audio/resampler/sinc_resampler.h" 19 20 namespace webrtc { 21 22 // Fake audio source for testing the resampler. Generates a sinusoidal linear 23 // chirp (http://en.wikipedia.org/wiki/Chirp) which can be tuned to stress the 24 // resampler for the specific sample rate conversion being used. 25 class SinusoidalLinearChirpSource : public SincResamplerCallback { 26 public: 27 // |delay_samples| can be used to insert a fractional sample delay into the 28 // source. It will produce zeros until non-negative time is reached. 29 SinusoidalLinearChirpSource(int sample_rate, size_t samples, 30 double max_frequency, double delay_samples); 31 ~SinusoidalLinearChirpSource()32 virtual ~SinusoidalLinearChirpSource() {} 33 34 void Run(size_t frames, float* destination) override; 35 36 double Frequency(size_t position); 37 38 private: 39 enum { 40 kMinFrequency = 5 41 }; 42 43 int sample_rate_; 44 size_t total_samples_; 45 double max_frequency_; 46 double k_; 47 size_t current_index_; 48 double delay_samples_; 49 50 RTC_DISALLOW_COPY_AND_ASSIGN(SinusoidalLinearChirpSource); 51 }; 52 53 } // namespace webrtc 54 55 #endif // WEBRTC_COMMON_AUDIO_RESAMPLER_SINUSOIDAL_LINEAR_CHIRP_SOURCE_H_ 56