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NAudio Get Audio Samples

I am using NAudio to get the sample from the song that is currently playing and draw the waveform as the song plays. I am using AudioFileReader and ToSampleProvider to get all samples as float and then I plot them into an InkCanvas while the song is playing. My problem is that the samples don't seem to match the sound. I also have verify this by using this same song in the WPF example that is located in the source code of NAudio. In the example the waveform matches the sound, but in my application it doesn't. So I was wondering if someone could help me find out what I am doing (or reading) wrong or if maybe my drawing logic is wrong.
Here is my current code:
public partial class MainWindow : Window, INotifyPropertyChanged
{
private ISampleProvider provider;
private DispatcherTimer timer;
private AudioFileReader reader;
private WaveOut waveOut;
private StylusPointCollection topPoints, bottomPoints;
private DrawingAttributes attr;
private double canvasHeight, canvasWidth;
private int samplesGroupSize;
private double drawPos = 0;
private StrokeCollection _WaveformLines;
public StrokeCollection WaveformLines
{
get { return _WaveformLines; }
set
{
_WaveformLines = value;
OnPropertyChanged("WaveformLines");
}
}
public MainWindow()
{
InitializeComponent();
this.DataContext = this;
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
reader = new AudioFileReader("C:\\Users\\Agustin\\Desktop\\DragonRider.mp3");
waveOut = new WaveOut();
waveOut.Init(reader);
provider = reader.ToSampleProvider(); //Here I get the samples
reader.Position = 0; //Go to the position 0 after reading the samples
canvasHeight = Waveform.ActualHeight;
canvasWidth = Waveform.ActualWidth;
WaveformLines = new StrokeCollection();
topPoints = new StylusPointCollection();
topPoints.Add(new StylusPoint(0, (canvasHeight / 2)));
topPoints.Changed += topPoints_Changed;
bottomPoints = new StylusPointCollection();
bottomPoints.Add(new StylusPoint(0, (canvasHeight / 2)));
bottomPoints.Changed += topPoints_Changed;
WaveformLines.Add(new Stroke(topPoints));
WaveformLines.Add(new Stroke(bottomPoints));
attr = new DrawingAttributes();
attr.Color = Colors.Green;
attr.Width = 1.5;
attr.Height = 1;
timer = new DispatcherTimer();
timer.Interval = TimeSpan.FromMilliseconds(1);
timer.Tick += timer_Tick;
timer.Start();
samplesGroupSize = (int)(timer.Interval.TotalSeconds * reader.WaveFormat.SampleRate); //The value for this is 44.
}
private void PlayButton_Click(object sender, RoutedEventArgs e)
{
waveOut.Play();
}
private void PauseButton_Click(object sender, RoutedEventArgs e)
{
waveOut.Pause();
}
private void timer_Tick(object sender, EventArgs e)
{
if (waveOut.PlaybackState == PlaybackState.Playing)
{
TimeLabel.Content = string.Format("Time: {0}", reader.CurrentTime.ToString(#"mm\:ss\:ff")); //NEED TO KEEP WORKING
float[] samps = new float[samplesGroupSize];
provider.Read(samps, 0, samps.Length);
float max = Max(samps);
float min = Min(samps);
topPoints.Add(new StylusPoint(drawPos, (canvasHeight / 2) - ((canvasHeight / 2) * max)));
bottomPoints.Add(new StylusPoint(drawPos, (canvasHeight / 2) - ((canvasHeight / 2) * min)));
drawPos += 2;
if (drawPos > canvasWidth)
{
WaveformLines.Clear();
topPoints = new StylusPointCollection();
topPoints.Add(new StylusPoint(0, (canvasHeight / 2)));
bottomPoints = new StylusPointCollection();
bottomPoints.Add(new StylusPoint(0, (canvasHeight / 2)));
WaveformLines.Add(new Stroke(topPoints));
WaveformLines.Add(new Stroke(bottomPoints));
drawPos = 0;
}
}
}
private float Min(float[] samps)
{
float max = samps[0];
foreach (float s in samps)
{
if (s > max)
max = s;
}
return max;
}
private float Max(float[] samps)
{
float min = samps[0];
foreach (float s in samps)
{
if (s < min)
min = s;
}
return min;
}
//I excluded the INotifyPropertyChanged implementation, but in the
//actual code is located here
}
I know this drawing algorithm is not very good but I have tried others and they also seem to not follow the audio.
Thanks.
NOTE: I know that there are similar question, but the other questions suggest to use things like AudioFileReader or ToSampleProvider which I am already using. My error is probably more into how I am reading the samples, maybe I am missing some bytes or have to skip some byte, or maybe some missing property that I am not setting.

You should seriously consider using the portions of the code from the WFP example that handles read/play and the min / max calculation work.
It will take you a little bit of effort but I promise it will be worth it.
You then will be working with a dataset that you know is in the correct form and you can focus on the drawing part. Look closely at AudioPlayback.cs and its relationship to SampleAggregator.cs.
You'll also find that getting automatic callbacks while the samples are being read (and played) is a much better way to refresh your waveform drawing than trying to use a DispatchTimer. It will also get you out of re-reading the wave buffer as well -- you really want to avoid that if you can.
EDIT:
I tested your conversion code and the resulting float values appear to be correct (in the range of -1 through 1). So I think the problem is with the way you are plotting the waveform in WPF.

Making an updating winform multi threaded

I have been breaking my head over this for a long time now and I can't seem to find how to solve this. Simply put I need to present Parallel programming to my class and i am making a demo that clearly shows the diffrence between single threaded and multi threaded.
First the program takes a screenshot and loads that in this class into a bitmap.
Then it loads the winform with a picturebox called screenshot. Next it does Form1_Load and loads the screenshot into the picturebox.
Then Form1_Shown Runs the for loop which just scrambles the pixels around based on a randomizer and updates the image from the left to the right.
example: http://gyazo.com/ab04583bb33de59d08407886da1c4870
This all works.
I now want to make it so that the screenshot is being updated from the left to the middle by the first thread, and from the middle to the right with the second thread.
But when i put it in 2 separate threads it says "An unhandled exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll"
The error implies I am making illegal cross thread calls. Particulary on screenshot and probably also on mybitmap.
Visual studio helps me by linking me to "How to: Make Thread-Safe Calls to Windows Forms Controls"
But i am not getting any wiser out of this information which is probably because i am not that fluent with the C# terminology yet.
How should i approach/fix this ?
This is the class where everything happens (except taking the screenshot):
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace ScreenOutput
{
public partial class Form1 : Form
{
PictureBox screenshot;
Bitmap myBitmap = new Bitmap(#".\screenshot.jpg");
public Form1()
{
InitializeComponent();
}
private int Xcount;
private int Ycount;
private int maxXValue = Screen.PrimaryScreen.Bounds.Width - 1;
private int maxXValueT1 = 960;
private int maxXValueT2 = 1919;
private int maxYValue = Screen.PrimaryScreen.Bounds.Height - 1;
private int maxYValueT1 = 539;
private int maxYValueT2 = 1079;
private void Form1_Load(object sender, EventArgs e)
{
screenshot.Image = myBitmap;
}
private void Form1_Shown(object sender, EventArgs e)
{
Thread startThread1 = new Thread(new ThreadStart(thread1));
Thread startThread2 = new Thread(new ThreadStart(thread2));
startThread1.Start();
startThread2.Start();
Thread.Sleep(10000); //waiting for completion
startThread1.Abort();
startThread2.Abort();
//this is how it would work without multithreading
/*Random random = new Random();
for (Xcount = 0; Xcount < maxXValue; Xcount++)
{
screenshot.Refresh();
for (Ycount = 0; Ycount < maxYValue; Ycount++)
{
int calculatedX = Xcount + random.Next(0, maxXValue);
if (calculatedX > maxXValue) calculatedX = maxXValue;
myBitmap.SetPixel(Xcount, Ycount, myBitmap.GetPixel(calculatedX, Ycount));
}
}
Thread.Sleep(2000);*/
Application.Exit();
}
public void thread1()
{
Random random = new Random();
for (Xcount = 0; Xcount < maxXValueT1; Xcount++)
{
screenshot.Refresh();
for (Ycount = 0; Ycount < maxYValueT1; Ycount++)
{
int calculatedX = Xcount + random.Next(0, maxXValueT1);
if (calculatedX > maxXValue) calculatedX = maxXValueT1;
myBitmap.SetPixel(Xcount, Ycount, myBitmap.GetPixel(calculatedX, Ycount));
}
}
}
public void thread2()
{
Random random = new Random();
for (Xcount = 0; Xcount < maxXValueT2; Xcount++)
{
screenshot.Refresh();
for (Ycount = 0; Ycount < maxYValueT2; Ycount++)
{
int calculatedX = Xcount + random.Next(0, maxXValueT2);
if (calculatedX > maxXValueT2) calculatedX = maxXValueT2;
myBitmap.SetPixel(Xcount, Ycount, myBitmap.GetPixel(calculatedX, Ycount));
}
}
}
}
}

You will need to Invoke the GUI thread.
I prefer the following solution.
Using a Form member ('screenshot' in this case) check to see if InvokeRequired = true. If so then Invoke a delegate using that members BeginInvoke() function as the following example demonstrates:
private void ScreenshotRefresh()
{
if(screenshot.InvokeRequired)
{
screenshot.BeginInvoke(new MethodInvoker(this.ScreenshotRefresh));
}
else
{
screenshot.Refresh();
}
}

C# - Zedgraph, plotting serial data too much delay and time lag

I'm new to C# programming and trying to write an application which is part of my final thesis.
I have a microprocessor that continuously send data from a sensor to my computer via serial port. All I want is to plotting this data using Zedgraph.
The problem is that the graph got too much delay and time lag. It seems the problem happens because I continuously update the whole graph at a very high rate.
I have stucked on this problem in a week and still dont find out a solution. I'll be more than happy if someone can help me out.
This is my code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using ZedGraph;
using System.IO.Ports;
using System.Threading;
namespace DynamicData
{
public partial class Form1 : Form
{
private SerialPort port;
private string buffer = "";
private void connect()
{
port = new SerialPort("COM8", 115200, Parity.None, 8, StopBits.One);
port.DataReceived += new System.IO.Ports.SerialDataReceivedEventHandler(port_DataReceived);
if (!port.IsOpen) port.Open();
}
public Form1()
{
InitializeComponent();
}
private void Form1_Load( object sender, EventArgs e )
{
connect();
GraphPane myPane = zedGraphControl1.GraphPane;
RollingPointPairList list = new RollingPointPairList(500);
LineItem curve = myPane.AddCurve( "Sensor", list, Color.Blue, SymbolType.None );
myPane.XAxis.Scale.Min = 0;
myPane.XAxis.Scale.Max = 10;
myPane.YAxis.Scale.Min = 0;
myPane.YAxis.Scale.Max = 300;
myPane.XAxis.Scale.MinorStep = 0.5;
myPane.XAxis.Scale.MajorStep = 1;
zedGraphControl1.AxisChange();
}
private void port_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
//sample data: ;100*100000:
//sampling rate ~100Hz
buffer += port.ReadExisting();
//flush incomplete package
while (buffer[0] != ';')
{
buffer = buffer.Remove(0, 1);
if (buffer.Length < 1) break;
}
//got a complete package, go to data handling
while (buffer.Contains(":"))
{
DataHandling();
}
}
private void DataHandling()
{
string[] nameArray = buffer.Split(new[] { ";", ":", "*" }, StringSplitOptions.RemoveEmptyEntries);
//plot sensor data vs. time
draw(Convert.ToInt32(nameArray[0]), Convert.ToInt32(nameArray[1]));
//remove handled package in buffer
var index = buffer.IndexOf(":");
buffer = buffer.Remove(0, index + 1);
}
double time = 0;
private void draw(int sensor, int t)
{
//convert tick to sec (uP clock rate = 16MHZ)
time = time + (t / 16000000.0);
// Get the first CurveItem in the graph
LineItem curve = zedGraphControl1.GraphPane.CurveList[0] as LineItem;
// Get the PointPairList
IPointListEdit list = curve.Points as IPointListEdit;
list.Add(time, sensor);
//Keep the X scale at a rolling 10 second interval, with one
//major step between the max X value and the end of the axis
Scale xScale = zedGraphControl1.GraphPane.XAxis.Scale;
if (time > xScale.Max - xScale.MajorStep)
{
xScale.Max = time + xScale.MajorStep;
xScale.Min = xScale.Max - 10.0;
}
//Display sensor data
this.Invoke(new Action(() => { textBox1.Text = byte1.ToString(); }));
axisChangeZedGraph(zedGraphControl1);
}
delegate void axisChangeZedGraphCallBack(ZedGraphControl zg);
private void axisChangeZedGraph(ZedGraphControl zg)
{
if (zg.InvokeRequired)
{
axisChangeZedGraphCallBack ad = new axisChangeZedGraphCallBack(axisChangeZedGraph);
zg.Invoke(ad, new object[] { zg });
}
else
{
// zg.AxisChange();
zg.Invalidate();
zg.Refresh();
}
}
}
}
Thank you for reading!

The problem is that you call invalidate with every point you draw. That produces a very high processor load. I'm working on a very similar project, USB device, realtime plotting data. I use a separate thread for data acquisition. This thread creates an event, every time it receives a datapacket. The data is put into a queue. The graph is updated with a timer. You find an example here. In this code the graph is updated every 50 ms, it is not really necessary to draw faster. In the timertick I check the size of the Queue and draw more or less points and then call invalidate. I don`t know if this is a good solution(just 6month experience in C#), but it works quite well with 7500 points. You should try to use a timer for the refresh of the graph first.

1). Create and format the the curve only once. store it at the module level.
2). When adding a point use curve.AddPoint(); then zg.Refresh();
//this is just to add a point to the plot, the curve object should have already been created
private void draw(int sensor, int t)
{
//convert tick to sec (uP clock rate = 16MHZ)
time = time + (t / 16000000.0);
//curve should be a module-level variable already set up with proper formatting,
//just no points yet
curve.AddPoint(time, sensor);
//Display sensor data
this.Invoke(new Action(() => { textBox1.Text = byte1.ToString(); }));
zg.AxisChange();
zg.Refresh();
}

How can i show the current animated gif speed?

I have this class that im getting the information from the animated gif:
using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Collections.Generic;
using System.IO;
public class AnimatedGif
{
private List<AnimatedGifFrame> mImages = new List<AnimatedGifFrame>();
public AnimatedGif(string path)
{
Image img = Image.FromFile(path);
int frames = img.GetFrameCount(FrameDimension.Time);
if (frames <= 1) throw new ArgumentException("Image not animated");
byte[] times = img.GetPropertyItem(0x5100).Value;
int frame = 0;
for (; ; )
{
int dur = BitConverter.ToInt32(times, 4 * frame);
mImages.Add(new AnimatedGifFrame(new Bitmap(img), dur));
if (++frame >= frames) break;
img.SelectActiveFrame(FrameDimension.Time, frame);
}
img.Dispose();
}
public List<AnimatedGifFrame> Images { get { return mImages; } }
}
public class AnimatedGifFrame
{
private int mDuration;
private Image mImage;
internal AnimatedGifFrame(Image img, int duration)
{
mImage = img; mDuration = duration;
}
public Image Image { get { return mImage; } }
public int Duration { get { return mDuration; } }
}
Then in Form1 in the constructor im looping over the List of images and get the duration of each of the images. So in the List in this case there are 4 images each one duration is 1.
So when im showing the animatd gif im trying to display the speed in a label.
But there are two problems:
The loop in the end show me that speed is now 2 not 4.
The label the result there is all the time 0 and 2/100 is not 0.
What i want to do is to show the actual speed.
Like in the program Easy gif animator 5:
If im standing on one image from the 4 i see that its speed is 0.01seconds wich is Delay 1 wich is 1/100th sec.
And if i mark all the images in the program i get speed 0.04 seconds.
Maybe i confusing between speed and duration.
I want to get the speed of the animated gif.
This is my code in Form1:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace MyAnimatedGifEditor
{
public partial class Form1 : Form
{
int speed;
Image myImage;
AnimatedGif myGif;
public Form1()
{
InitializeComponent();
myImage = Image.FromFile(#"D:\fananimation.gif");
myGif = new AnimatedGif(#"D:\fananimation.gif");
for (int i = 0; i < myGif.Images.Count; i++)
{
speed = myGif.Images[i].Duration;
speed++;
}
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void openToolStripMenuItem_Click(object sender, EventArgs e)
{
pictureBox1.Image = myImage;
label2.Text = (speed / 100).ToString();
}
}
}
Image from the easy gif animator after selected all images:
In the end i want to show on two labels one the duration of the animated gif and one the speed.

There is a problem with the portion of your code where you are looping through the images of the animated gif. You probably want two separate variables here instead of just speed.
So something like
for (int i = 0; i < myGif.Images.Count; i++)
{
totalDuration += myGif.Images[i].Duration;
count++;
}
And to solve your integer math problem, divide by 100.0 instead of 100:
label2.Text = (totalDuration / 100.0).ToString();

Creating a Huge Dummy File in a Matter of Seconds in C#

I want to create a huge dummy file say 1~2 GBs in matter of seconds.
here is what I've written in C#:
file.writeallbytes("filename",new byte[a huge number]);
and another way with indicating the status, was like following:
long FSS = din.TotalFreeSpace;
long segments = FSS / 10000;
long last_seg = FSS % 10000;
BinaryWriter br = new BinaryWriter(fs);
for (long i = 0; i < segments; i++)
{
br.Write(new byte[10000]);
this.label2.Text = "segments write :" + i.ToString() + "\r\n" + "segments remain :" + ((segments-i)+1).ToString();
Application.DoEvents();
}
br.Write(new byte[last_seg]);
this.label2.Text += "\r\nDone!";
br.Close();
where din is Disk Information object
well with these two approach it takes something like 2 or more minutes to write such a big but dummy file. Is there any other faster way for doing so?

Simply create the file, seek to a suitably large offset, and write a single byte:
FileStream fs = new FileStream(#"c:\tmp\huge_dummy_file", FileMode.CreateNew);
fs.Seek(2048L * 1024 * 1024, SeekOrigin.Begin);
fs.WriteByte(0);
fs.Close();
This will yield a 2GB file with basically unpredictable contents, which should be fine for your purposes.

If you don't care about the contents, then by far the fastest way I know of is this - it is practically instant:
private void CreateDummyFile(string fileName, long length)
{
using (var fileStream = new FileStream(fileName, FileMode.Create, FileAccess.Write, FileShare.None))
{
fileStream.SetLength(length);
}
}

If you just need a FileStream, you could use FileStream.SetLength. That will get you a stream which is 2 GB long. Then you can write the final byte at an arbitrary position of your choice. But the contents will be undefined.
If you're trying to actually create a file on the disk, yes, you'll need to actually write its contents. And yes, hard disks are going to be slow; something like a 1 GB/min write speed isn't totally ridiculous. Sorry -- that's physics!

Why did you not use the BackgroundWorker class to achieve this, as you can pass anything into the method ReportProgress to indicate the status report. See the example below:
private BackgroundWorker bgWorker;
public Form1()
{
InitializeComponent();
bgWorker = new BackgroundWorker();
bgWorker.DoWork += new DoWorkEventHandler(bgWorker_DoWork);
bgWorker.ProgressChanged += new ProgressChangedEventHandler(bgWorker_ProgressChanged);
bgWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgWorker_RunWorkerCompleted);
bgWorker.RunWorkerAsync();
}
void bgWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
this.label2.Text = "Done";
}
void bgWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
MyStatus myProgressStatus = (MyStatus)e.UserState;
this.label2.Text = string.Format("segments write : {0}" + Environment.Newline + "Segments Remain: {1}", myProgressStatus.iWritten, myProgressStatus.iRemaining);
}
void bgWorker_DoWork(object sender, DoWorkEventArgs e)
{
long FSS = din.TotalFreeSpace;
long segments = FSS / 10000;
long last_seg = FSS % 10000;
BinaryWriter br = new BinaryWriter(fs);
for (long i = 0; i < segments; i++)
{
br.Write(new byte[10000]);
bgWorker.ReportProgress(i.ToString(), new MyStatus(i, ((segments-i) + 1)));
}
br.Write(new byte[last_seg]);
br.Close();
}
public class MyStatus{
public int iWritten;
public int iRemaining;
public MyStatus(int iWrit, int iRem){
this.iWritten = iWrit;
this.iRemaining = iRem;
}
}
}
This is a rough draft...

I could be wrong but you will probably find that it's impossible to create a file that large that quickly as there will be a bottleneck in the I/O writing process.
However in your code above the Applciation.DoEvents will be slowing things down. Also any repainting of the screenthis.label2.Text = will cause a slight slow down.