Click here to Skip to main content
11,428,497 members (62,622 online)
Click here to Skip to main content

Sound visualizer in C#

, 15 Aug 2007 GPL3
Rate this:
Please Sign up or sign in to vote.
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)

Share

About the Author

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

Comments and Discussions

 
GeneralRe: Media File Pin
Babgi26-Mar-09 10:12
memberBabgi26-Mar-09 10:12 
GeneralRe: Media File Pin
Ankur Dukare11-Mar-10 23:35
memberAnkur Dukare11-Mar-10 23:35 
GeneralRe: Media File Pin
Eric Hdz25-Apr-15 15:43
memberEric Hdz25-Apr-15 15:43 
GeneralShutdown addition Pin
firmwaredsp31-Oct-07 23:26
memberfirmwaredsp31-Oct-07 23:26 
GeneralRe: Shutdown addition Pin
Ri Qen-Sin20-Nov-07 18:39
memberRi Qen-Sin20-Nov-07 18:39 
GeneralRe: Shutdown addition Pin
Jeff Morton27-Nov-07 3:57
memberJeff Morton27-Nov-07 3:57 
GeneralRe: Shutdown addition Pin
firmwaredsp28-Nov-07 0:21
memberfirmwaredsp28-Nov-07 0:21 
QuestionHow it works?? Pin
Ibrahim Dwaikat28-Oct-07 10:22
memberIbrahim Dwaikat28-Oct-07 10:22 
Hi


I am sorry to say that i cant use this application

I played a media file and run the application but nothing changed

!!!!



Visit Me

www.engibrahim.tk

AnswerRe: How it works?? Pin
j_morton28-Oct-07 10:29
memberj_morton28-Oct-07 10:29 
GeneralRe: How it works?? Pin
Ibrahim Dwaikat28-Oct-07 10:34
memberIbrahim Dwaikat28-Oct-07 10:34 
GeneralRe: How it works?? Pin
firmwaredsp31-Oct-07 23:47
memberfirmwaredsp31-Oct-07 23:47 
GeneralRe: How it works?? Pin
Jeff Morton28-Nov-07 4:44
memberJeff Morton28-Nov-07 4:44 
GeneralVery nice Pin
blackjack215023-Oct-07 2:01
memberblackjack215023-Oct-07 2:01 
QuestionHow To Get Frequency, or Period of the Wave? Pin
Paul Chin PC29-Sep-07 5:45
memberPaul Chin PC29-Sep-07 5:45 
QuestionDoesn't work :( Pin
Vladimir Grankovsky27-Aug-07 2:39
memberVladimir Grankovsky27-Aug-07 2:39 
AnswerRe: Doesn't work :( Pin
JeffMorton28-Aug-07 8:08
memberJeffMorton28-Aug-07 8:08 
GeneralRe: Doesn't work :( [modified] Pin
meliton gavia8-Jan-09 18:08
membermeliton gavia8-Jan-09 18:08 
AnswerRe: Doesn't work :( Pin
ajgreen198723-Jul-09 6:36
memberajgreen198723-Jul-09 6:36 
AnswerRe: Doesn't work :( Pin
Terricide15-Oct-09 23:11
memberTerricide15-Oct-09 23:11 
Questionquestion about wav using Pin
headburster22-Aug-07 0:29
memberheadburster22-Aug-07 0:29 
AnswerRe: question about wav using Pin
Jaguar++29-Aug-07 23:18
memberJaguar++29-Aug-07 23:18 
Questionvs version? Pin
headburster22-Aug-07 0:02
memberheadburster22-Aug-07 0:02 
AnswerRe: vs version? Pin
JeffMorton28-Aug-07 8:12
memberJeffMorton28-Aug-07 8:12 
GeneralThanks Pin
merlin98116-Aug-07 4:57
membermerlin98116-Aug-07 4:57 
GeneralThanks. this is what I was looking for. Pin
Michael Sync15-Aug-07 21:22
memberMichael Sync15-Aug-07 21:22 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

| Advertise | Privacy | Terms of Use | Mobile
Web02 | 2.8.150428.2 | Last Updated 15 Aug 2007
Article Copyright 2007 by Jeff Morton
Everything else Copyright © CodeProject, 1999-2015
Layout: fixed | fluid