Stop audio recorder on its own after time delay in c# ( using NAudio)

Question

I am making an audio recorded using NAudio in C# and i need to remove the stop button used and simply stop the recording on its own after some time delay.

The code for the record event is

     private void cmbRecord_Click(object sender, EventArgs e)
     {
            outputFilename = "file address";

            waveInStream = new WaveIn(44100,2);
            writer = new WaveFileWriter(outputFilename, waveInStream.WaveFormat);

            waveInStream.DataAvailable += new EventHandler<WaveInEventArgs>(waveInStream_DataAvailable);
            waveInStream.StartRecording();


            // Just controling the objects on the screen.
            cmbRecord.Enabled = false;
            cmbStop.Enabled = true;

    } 


     void waveInStream_DataAvailable(object sender, WaveInEventArgs e)
    {
        writer.WriteData(e.Buffer, 0, e.BytesRecorded);
        int secondsRecorded = (int)(writer.Length / writer.WaveFormat.AverageBytesPerSecond);

    }

The stop button is given as

      private void cmbStop_Click(object sender, EventArgs e)
    {
        waveInStream.StopRecording();
        waveInStream.Dispose();
        waveInStream = null;
        writer.Close();
        writer = null;

        cmbRecord.Enabled = true;
        cmbStop.Enabled = false;
    }

I need to stop the recording automatically inside the cmbRecord_Click event. Thanks in advance.

Answer 1

use a Timer, set the Interval and copy the code in cmbStop_Click event over to timer's OnTick event. Enable the timer in the mbRecord_Click event and & remember to disable the timer in cmbStop_Click event

Edit:

Create a new timer and set its value

//put this line in your form class level

  System.Windows.Forms.Timer mytimer=new System.Windows.Forms.Timer(); //create a new Timer

//put these two into your form constructor just after InitializeComponent();

mytimer.Interval=1000; //set the interval to 1 second.
mytimer.Tick += new EventHandler(mytimer_Tick);

Enable the timer in the mbRecord_Click event

private void cmbRecord_Click(object sender, EventArgs e)
{
            outputFilename = "file address";

            waveInStream = new WaveIn(44100,2);
            writer = new WaveFileWriter(outputFilename, waveInStream.WaveFormat);

            waveInStream.DataAvailable += new EventHandler<WaveInEventArgs>(waveInStream_DataAvailable);
            waveInStream.StartRecording();


            // Just controling the objects on the screen.
            cmbRecord.Enabled = false;
            cmbStop.Enabled = true;

            //Enable the timer to fire
            mytimer.Enabled = true;

}

Stop recording after 1 second..

void mytimer_Tick(object sender, EventArgs e)
{       
        waveInStream.StopRecording();
        waveInStream.Dispose();
        waveInStream = null;
        writer.Close();
        writer = null;

        cmbRecord.Enabled = true;
        cmbStop.Enabled = false;
//disable the timer here so it won't fire again...
        mytimer.Enabled = false;
}

Answer 2

One thing you may want to bear in mind - there will be a DataAvailable callback after the call to StopRecording (or during, depending on the callback model used), so you might want to delay closing the WaveFileWriter until you have written everything.

Have a look at the VoiceRecorder sample project which uses NAudio and stops recording after 60 seconds. I explain in this article how recording is automatically stopped.

long maxFileLength = this.recordingFormat.AverageBytesPerSecond * 60;

int toWrite = (int)Math.Min(maxFileLength - writer.Length, bytesRecorded);
if (toWrite > 0)
    writer.WriteData(buffer, 0, bytesRecorded);
else
    Stop();