test_util.h

/*
Copyright 2018 Google Inc. All Rights Reserved.
 
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
 
    http://www.apache.org/licenses/LICENSE-2.0
 
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS-IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
 
#ifndef RESONANCE_AUDIO_UTILS_TEST_UTIL_H_
#define RESONANCE_AUDIO_UTILS_TEST_UTIL_H_
 
#include <cstddef>
#include <vector>
 
#include "base/integral_types.h"
#include "base/audio_buffer.h"
 
namespace vraudio {
 
// Silences an audio channel.
void GenerateSilence(AudioBuffer::Channel* output);
 
// Generates a sine wave at the specified frequency in hertz at the given
// sampling rate in hertz.
void GenerateSineWave(float frequency_hz, int sample_rate,
                      AudioBuffer::Channel* output);
 
// Generates a saw tooth signal between -1 and 1 for the given wave form length.
void GenerateSawToothSignal(size_t tooth_length_samples,
                            AudioBuffer::Channel* output);
 
// Generates a Dirac impulse filter kernel, which delays filtered signals by
// the given delay.
void GenerateDiracImpulseFilter(size_t delay_samples,
                                AudioBuffer::Channel* output);
 
// Generates a linear ramp signal between -1 and 1.
void GenerateIncreasingSignal(AudioBuffer::Channel* output);
 
// Returns the index of the first non-zero element.
size_t ZeroCompare(const AudioBuffer::Channel& signal, float epsilon);
 
// Compares the content of two audio channels. Returns true if the absolute
// difference between all samples is below epsion.
bool CompareAudioBuffers(const AudioBuffer::Channel& buffer_a,
                         const AudioBuffer::Channel& buffer_b, float epsilon);
 
// Returns delayed_signal.size() in output if delayed_signal is approximately
// equal to original_signal delayed by the given amount; otherwise, returns the
// index of the first unequal element in delayed_signal.
size_t DelayCompare(const AudioBuffer::Channel& original_signal,
                    const AudioBuffer::Channel& delayed_signal, size_t delay,
                    float epsilon);
 
// Test if two signals are shifted by a fixed number of samples with zero
// padding.
bool TestZeroPaddedDelay(const AudioBuffer::Channel& original_signal,
                         const AudioBuffer::Channel& delayed_signal,
                         size_t delay_samples, float epsilon);
 
// Returns absolute peak amplitude of a signal.
double CalculateSignalPeak(const AudioBuffer::Channel& channel);
 
// Returns energy of a signal.
double CalculateSignalEnergy(const AudioBuffer::Channel& channel);
 
// Returns Root Mean Square (RMS) of a signal.
double CalculateSignalRms(const AudioBuffer::Channel& channel);
 
// Expresses a magnitude measurement in dB.
double DbFromMagnitude(double magnitude);
 
// Expresses a power measurement in dB.
double DbFromPower(double power);
 
// Returns the maximum cross correlation value between two signals.
// To be used only with signals of the same length.
float MaxCrossCorrelation(const AudioBuffer::Channel& signal_a,
                          const AudioBuffer::Channel& signal_b);
 
}  // namespace vraudio
 
#endif  // RESONANCE_AUDIO_UTILS_TEST_UTIL_H_