NAudio pcm record with "winmm.dll" - Casual "AccessViolationException" on waveInPrepareHeader

[FossaMalaEnt]

Hi,

My application (.NET 7), sometimes crash when I'm trying to start recording using NAudio WaveIn with the following error

System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt. Stack: at NAudio.Wave.WaveInterop.waveInPrepareHeader(IntPtr, NAudio.Wave.WaveHeader, Int32) at NAudio.Wave.WaveInterop.waveInPrepareHeader(IntPtr, NAudio.Wave.WaveHeader, Int32) at NAudio.Wave.WaveInBuffer.Reuse() at NAudio.Wave.WaveInEvent.DoRecording() at NAudio.Wave.WaveInEvent.RecordThread() at System.Threading.QueueUserWorkItemCallback.Execute() at System.Threading.ThreadPoolWorkQueue.Dispatch() at System.Threading.PortableThreadPool+WorkerThread.WorkerThreadStart()

This is how i start the recording on user interaction;

if (this.PcmWaveIn == null)
{
    Console.WriteLine("PcmWaveIn init started...");

    this.PcmWaveIn = new WaveInEvent
    {
        DeviceNumber = 0,
        WaveFormat = new WaveFormat(rate: 8000, bits: 16, channels: 1),
        BufferMilliseconds = 20
    };

    this.PcmWaveIn.DataAvailable += (object? sender, WaveInEventArgs e) =>
    {
        // copy buffer into an array of integers
        Int16[] values = new Int16[e.Buffer.Length / 2];
        Buffer.BlockCopy(e.Buffer, 0, values, 0, e.Buffer.Length);

        // Perform A-law encoding
        byte[] alawData = new byte[e.Buffer.Length / 2];
        for (int i = 0; i < e.Buffer.Length; i += 2)
        {
            short sample = BitConverter.ToInt16(e.Buffer, i);
            alawData[i / 2] = NAudio.Codecs.ALawEncoder.LinearToALawSample(sample);
        }
        // Do things....
    };

    Console.WriteLine("PcmWaveIn init complete...");
}
this.PcmWaveIn.StartRecording();

And then simply stop with: this.PcmWaveIn?.StopRecording();

I always leave the application running, and this issue sometimes occurs on the same day I start the software, or sometimes after a week or a few days. The application also makes extensive use of multithreading. Could this affect how the library manages resources?

[markheath]

An access violation can be hard to track down because it could be completely different code that is corrupting memory. Is there any other unsafe code or interop involved?