examples.cpp

#include <iostream>
#include <cmath>
#include <AudioFile.h>

 //=======================================================================
 namespace examples
 {
     void writeSineWaveToAudioFile();
     void loadAudioFileAndPrintSummary();
     void loadAudioFileAndProcessSamples();
 }

//=======================================================================
int main()
{
    //---------------------------------------------------------------
    /** Writes a sine wave to an audio file */
    examples::writeSineWaveToAudioFile();
    
    //---------------------------------------------------------------
    /** Loads an audio file and prints key details to the console*/
    examples::loadAudioFileAndPrintSummary();
    
    //---------------------------------------------------------------
    /** Loads an audio file and processess the samples */
    examples::loadAudioFileAndProcessSamples();
        
    return 0;
}

//=======================================================================
namespace examples
{
    //=======================================================================
    void writeSineWaveToAudioFile()
    {
        //---------------------------------------------------------------
        std::cout << "**********************" << std::endl;
        std::cout << "Running Example: Write Sine Wave To Audio File" << std::endl;
        std::cout << "**********************" << std::endl << std::endl;
        
        //---------------------------------------------------------------
        // 1. Let's setup our AudioFile instance
        
        AudioFile<float> a;
        a.setNumChannels (2);
        a.setNumSamplesPerChannel (44100);

        //---------------------------------------------------------------
        // 2. Create some variables to help us generate a sine wave
        
        const float sampleRate = 44100.f;
        const float frequencyInHz = 440.f;
        
        //---------------------------------------------------------------
        // 3. Write the samples to the AudioFile sample buffer
        
        for (int i = 0; i < a.getNumSamplesPerChannel(); i++)
        {
            for (int channel = 0; channel < a.getNumChannels(); channel++)
            {
                a.samples[channel][i] = sin ((static_cast<float> (i) / sampleRate) * frequencyInHz * 2.f * (float)M_PI);
            }
        }
        
        //---------------------------------------------------------------
        // 4. Save the AudioFile
        
        std::string filePath = "sine-wave.wav"; // change this to somewhere useful for you
        a.save ("sine-wave.wav", AudioFileFormat::Wave);
    }
    
    //=======================================================================
    void loadAudioFileAndPrintSummary()
    {
        //---------------------------------------------------------------
        std::cout << "**********************" << std::endl;
        std::cout << "Running Example: Load Audio File and Print Summary" << std::endl;
        std::cout << "**********************" << std::endl << std::endl;
        
        //---------------------------------------------------------------
        // 1. Set a file path to an audio file on your machine
        const std::string filePath = std::string (PROJECT_BINARY_DIR) + "/test-audio.wav";
        
        //---------------------------------------------------------------
        // 2. Create an AudioFile object and load the audio file
        
        AudioFile<float> a;
        bool loadedOK = a.load (filePath);
        
        /** If you hit this assert then the file path above
         probably doesn't refer to a valid audio file */
        assert (loadedOK);
        
        //---------------------------------------------------------------
        // 3. Let's print out some key details
        
        std::cout << "Bit Depth: " << a.getBitDepth() << std::endl;
        std::cout << "Sample Rate: " << a.getSampleRate() << std::endl;
        std::cout << "Num Channels: " << a.getNumChannels() << std::endl;
        std::cout << "Length in Seconds: " << a.getLengthInSeconds() << std::endl;
        std::cout << std::endl;
    }
    
    //=======================================================================
    void loadAudioFileAndProcessSamples()
    {
        //---------------------------------------------------------------
        std::cout << "**********************" << std::endl;
        std::cout << "Running Example: Load Audio File and Process Samples" << std::endl;
        std::cout << "**********************" << std::endl << std::endl;
        
        //---------------------------------------------------------------
        // 1. Set a file path to an audio file on your machine
        const std::string inputFilePath = std::string (PROJECT_BINARY_DIR) + "/test-audio.wav";
        
        //---------------------------------------------------------------
        // 2. Create an AudioFile object and load the audio file
        
        AudioFile<float> a;
        bool loadedOK = a.load (inputFilePath);
        
        /** If you hit this assert then the file path above
         probably doesn't refer to a valid audio file */
        assert (loadedOK);
        
        //---------------------------------------------------------------
        // 3. Let's apply a gain to every audio sample
        
        float gain = 0.5f;

        for (int i = 0; i < a.getNumSamplesPerChannel(); i++)
        {
            for (int channel = 0; channel < a.getNumChannels(); channel++)
            {
                a.samples[channel][i] = a.samples[channel][i] * gain;
            }
        }
        
        //---------------------------------------------------------------
        // 4. Write audio file to disk
        
        std::string outputFilePath = "quieter-audio-file.wav"; // change this to somewhere useful for you
        a.save (outputFilePath, AudioFileFormat::Aiff);
    }
}