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Sound visualizer in C#

, 15 Aug 2007 GPL3 439K 23.2K 216
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Simple sound sampler with visualization
Screenshot - SoundViewer.jpg

Introduction

This project demonstrates the use of the Fast Fourier Transform and Windows GDI to produce near real-time visualizations of the time and frequency domains of sound.

Background

While looking for information on signal processing for a robotics project, it became apparent that examples written in C# were hard to find. This led me to create some of my own classes, which I have provided here for this demonstration.

Using the Code

Audio input for this demonstration is provided by the Wave classes developed by Ianier Munoz. Wave samples are further processed using the AudioFrame class.

class AudioFrame
{
    private Bitmap _canvasTimeDomain;
    private Bitmap _canvasFrequencyDomain;
    private double[] _waveLeft;
    private double[] _waveRight;
    private double[] _fftLeft;
    private double[] _fftRight;
    private SignalGenerator _signalGenerator;
    private bool _isTest = false;
    public AudioFrame(bool isTest)
    {
        _isTest = isTest;
    }

    /// <span class="code-SummaryComment"><summary>
</span>
    /// Process 16 bit sample
    /// <span class="code-SummaryComment"></summary>
</span>
    /// <span class="code-SummaryComment"><param name="wave"></param>
</span>
    public void Process(ref byte[] wave)
    {
        _waveLeft = new double[wave.Length / 4];
        _waveRight = new double[wave.Length / 4];
        if (_isTest == false)
        {
            // Split out channels from sample
            int h = 0;
            for (int i = 0; i < wave.Length; i += 4)
            {
                _waveLeft[h] = (double)BitConverter.ToInt16(wave, i);
                _waveRight[h] = (double)BitConverter.ToInt16(wave, i + 2);
                h++;
            }
        }
        else
        {
            // Generate artificial sample for testing
            _signalGenerator = new SignalGenerator();
            _signalGenerator.SetWaveform("Sine");
            _signalGenerator.SetSamplingRate(44100);
            _signalGenerator.SetSamples(16384);
            _signalGenerator.SetFrequency(5000);
            _signalGenerator.SetAmplitude(32768);
            _waveLeft = _signalGenerator.GenerateSignal();
            _waveRight = _signalGenerator.GenerateSignal();
        }
        // Generate frequency domain data in decibels
        _fftLeft = FourierTransform.FFTDb(ref _waveLeft);
        _fftRight = FourierTransform.FFTDb(ref _waveRight);
    }

    /// <span class="code-SummaryComment"><summary>
</span>
    /// Render time domain to PictureBox
    /// <span class="code-SummaryComment"></summary>
</span>
    /// <span class="code-SummaryComment"><param name="pictureBox"></param>
</span>
    public void RenderTimeDomain(ref PictureBox pictureBox)
    {
        // Set up for drawing
        _canvasTimeDomain = new Bitmap(pictureBox.Width, pictureBox.Height);
        Graphics offScreenDC = Graphics.FromImage(_canvasTimeDomain);
        SolidBrush brush = new System.Drawing.SolidBrush
                    (Color.FromArgb(0, 0, 0));
        Pen pen = new System.Drawing.Pen(Color.WhiteSmoke);
        // Determine channel boundaries
        int width = _canvasTimeDomain.Width;
        int center = _canvasTimeDomain.Height / 2;
        int height = _canvasTimeDomain.Height;
        offScreenDC.DrawLine(pen, 0, center, width, center);
        int leftLeft = 0;
        int leftTop = 0;
        int leftRight = width;
        int leftBottom = center - 1;
        int rightLeft = 0;
        int rightTop = center + 1;
        int rightRight = width;
        int rightBottom = height;
        // Draw left channel
        double yCenterLeft = (leftBottom - leftTop) / 2;
        double yScaleLeft = 0.5 * (leftBottom - leftTop) / 32768;  
            // a 16 bit sample has values from -32768 to 32767
        int xPrevLeft = 0, yPrevLeft = 0;
        for (int xAxis = leftLeft; xAxis < leftRight; xAxis++)
        {
            int yAxis = (int)(yCenterLeft + (_waveLeft[_waveLeft.Length / 
                (leftRight - leftLeft) * xAxis] * yScaleLeft));
            if (xAxis == 0)
            {
                xPrevLeft = 0;
                yPrevLeft = yAxis;
            }
            else
            {
                pen.Color = Color.LimeGreen;
                offScreenDC.DrawLine(pen, xPrevLeft, yPrevLeft, xAxis,yAxis);
                xPrevLeft = xAxis;
                yPrevLeft = yAxis;
            }
        }
        // Draw right channel
        int xCenterRight = rightTop + ((rightBottom - rightTop) / 2);
        double yScaleRight = 0.5 * (rightBottom - rightTop) / 32768;  
            // a 16 bit sample has values from -32768 to 32767
        int xPrevRight = 0, yPrevRight = 0;
        for (int xAxis = rightLeft; xAxis < rightRight; xAxis++)
        {
            int yAxis = (int)(xCenterRight + (_waveRight[_waveRight.Length / 
            (rightRight - rightLeft) * xAxis] * yScaleRight));
            if (xAxis == 0)
            {
                xPrevRight = 0;
                yPrevRight = yAxis;
            }
            else
            {
                pen.Color = Color.LimeGreen;
                offScreenDC.DrawLine
                (pen, xPrevRight, yPrevRight, xAxis, yAxis);
                xPrevRight = xAxis;
                yPrevRight = yAxis;
            }
        }
        // Clean up
        pictureBox.Image = _canvasTimeDomain;
        offScreenDC.Dispose();
    }

    /// <span class="code-SummaryComment"><summary>
</span>
    /// Render frequency domain to PictureBox
    /// <span class="code-SummaryComment"></summary>
</span>
    /// <span class="code-SummaryComment"><param name="pictureBox"></param>
</span>
    public void RenderFrequencyDomain(ref PictureBox pictureBox)
    {
        // Set up for drawing
        _canvasFrequencyDomain = new Bitmap
                (pictureBox.Width, pictureBox.Height);
        Graphics offScreenDC = Graphics.FromImage(_canvasFrequencyDomain);
        SolidBrush brush = new System.Drawing.SolidBrush
                    (Color.FromArgb(0, 0, 0));
        Pen pen = new System.Drawing.Pen(Color.WhiteSmoke);
        // Determine channel boundaries
        int width = _canvasFrequencyDomain.Width;
        int center = _canvasFrequencyDomain.Height / 2;
        int height = _canvasFrequencyDomain.Height;
        offScreenDC.DrawLine(pen, 0, center, width, center);
        int leftLeft = 0;
        int leftTop = 0;
        int leftRight = width;
        int leftBottom = center - 1;
        int rightLeft = 0;
        int rightTop = center + 1;
        int rightRight = width;
        int rightBottom = height;
        // Draw left channel
        for (int xAxis = leftLeft; xAxis < leftRight; xAxis++)
        {
            double amplitude = (int)_fftLeft[(int)(((double)(_fftLeft.Length)
                         / (double)(width)) * xAxis)];
            if (amplitude < 0) // Drop negative values
            amplitude = 0;
            int yAxis = (int)(leftTop + 
                ((leftBottom - leftTop) * amplitude) / 100);  
                        // Arbitrary factor
            pen.Color = Color.FromArgb(0, 0, (int)amplitude % 255);
            offScreenDC.DrawLine(pen, xAxis, leftTop, xAxis, yAxis);
        }
        // Draw right channel
        for (int xAxis = rightLeft; xAxis < rightRight; xAxis++)
        {
            double amplitude = (int)_fftRight[(int)(((double)
            (_fftRight.Length) / (double)(width)) * xAxis)];
            if (amplitude < 0)
            amplitude = 0;
            int yAxis = (int)(rightBottom - 
            ((rightBottom - rightTop) * amplitude) / 100);
            pen.Color = Color.FromArgb(0, 0, (int)amplitude % 255);
            offScreenDC.DrawLine(pen, xAxis, rightBottom, xAxis, yAxis);
        }
        // Clean up
        pictureBox.Image = _canvasFrequencyDomain;
        offScreenDC.Dispose();
    }
}

License

This article, along with any associated source code and files, is licensed under The GNU General Public License (GPLv3)

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About the Author

Jeff Morton
Systems / Hardware Administrator
United States United States
No Biography provided

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Comments and Discussions

 
AnswerRe: audioFrameSize in waveformat correct ? Pin
Jeff Morton8-Mar-09 9:59
memberJeff Morton8-Mar-09 9:59 
GeneralIt won't work on desktop PC Pin
max_99014-Feb-09 0:15
membermax_99014-Feb-09 0:15 
QuestionInput delays Pin
Joe Wright1-Sep-08 7:12
memberJoe Wright1-Sep-08 7:12 
AnswerRe: Input delays Pin
Jeff Morton1-Sep-08 12:45
memberJeff Morton1-Sep-08 12:45 
GeneralIt works! Pin
Member 470880128-Aug-08 21:08
memberMember 470880128-Aug-08 21:08 
GeneralShutdown addition Pin
firmwaredsp31-Oct-07 22:26
memberfirmwaredsp31-Oct-07 22:26 
GeneralRe: Shutdown addition Pin
Ri Qen-Sin20-Nov-07 17:39
memberRi Qen-Sin20-Nov-07 17:39 
GeneralRe: Shutdown addition Pin
Jeff Morton27-Nov-07 2:57
memberJeff Morton27-Nov-07 2:57 
GeneralRe: Shutdown addition Pin
firmwaredsp27-Nov-07 23:21
memberfirmwaredsp27-Nov-07 23:21 
QuestionHow it works?? Pin
Ibrahim Dwaikat28-Oct-07 9:22
memberIbrahim Dwaikat28-Oct-07 9:22 
AnswerRe: How it works?? Pin
j_morton28-Oct-07 9:29
memberj_morton28-Oct-07 9:29 
GeneralRe: How it works?? Pin
Ibrahim Dwaikat28-Oct-07 9:34
memberIbrahim Dwaikat28-Oct-07 9:34 
GeneralRe: How it works?? Pin
firmwaredsp31-Oct-07 22:47
memberfirmwaredsp31-Oct-07 22:47 
GeneralRe: How it works?? Pin
Jeff Morton28-Nov-07 3:44
memberJeff Morton28-Nov-07 3:44 
Basically, this program is an extension of previous work done by Ianier Munoz.

See "A full-duplex audio player in C# using the waveIn/waveOut APIs" for details on those classes.
http://www.codeproject.com/cs/media/cswavrec.asp[^]

That being the case, my intention was to grab input from the microphone and do some digital signal procesing on it which is what I've provided here as an example. I did not originally flesh out the code to make it particularly user freindly, but now that I see that there is interest I intend to create an updated article in the near future with much richer features.

To answer your question I would suggest identifying your audio input device and make sure that it is configured properly.

The relevant line of code is

_recorder = new WaveInRecorder(0, _waveFormat, _audioFrameSize * 2, 3, new BufferDoneEventHandler(DataArrived));

In this case the device is set to 0 which is the first device and the functioning microphone on my system. This may of course be different in your situation.

I would also check to make sure that your microphone is functioning properly and that it is not muted etc..

Also, _isPlayer is used to toggle audio output in this example and that device is set here

_player = new WaveOutPlayer(-1, _waveFormat, _audioFrameSize * 2, 3, new BufferFillEventHandler(Filler));

This was an unnecessary feature so I set this to false by default.
GeneralVery nice Pin
blackjack215023-Oct-07 1:01
memberblackjack215023-Oct-07 1:01 
QuestionHow To Get Frequency, or Period of the Wave? Pin
Paul Chin PC29-Sep-07 4:45
memberPaul Chin PC29-Sep-07 4:45 
QuestionDoesn't work :( Pin
Vladimir Grankovsky27-Aug-07 1:39
memberVladimir Grankovsky27-Aug-07 1:39 
AnswerRe: Doesn't work :( Pin
JeffMorton28-Aug-07 7:08
memberJeffMorton28-Aug-07 7:08 
GeneralRe: Doesn't work :( [modified] Pin
meliton gavia8-Jan-09 17:08
membermeliton gavia8-Jan-09 17:08 
AnswerRe: Doesn't work :( Pin
ajgreen198723-Jul-09 5:36
memberajgreen198723-Jul-09 5:36 
AnswerRe: Doesn't work :( Pin
Terricide15-Oct-09 22:11
memberTerricide15-Oct-09 22:11 
Questionquestion about wav using Pin
headburster21-Aug-07 23:29
memberheadburster21-Aug-07 23:29 
AnswerRe: question about wav using Pin
Jaguar++29-Aug-07 22:18
memberJaguar++29-Aug-07 22:18 
Questionvs version? Pin
headburster21-Aug-07 23:02
memberheadburster21-Aug-07 23:02 
AnswerRe: vs version? Pin
JeffMorton28-Aug-07 7:12
memberJeffMorton28-Aug-07 7:12 
GeneralThanks Pin
merlin98116-Aug-07 3:57
membermerlin98116-Aug-07 3:57 
GeneralThanks. this is what I was looking for. Pin
Michael Sync15-Aug-07 20:22
memberMichael Sync15-Aug-07 20:22 

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