Question

我有一个小型的c＃应用程序，它使用waveout接口定期调用waveoutwrite将音频数据写入声卡。我不使用NAudio，因为我需要使用8192字节的固定缓冲区大小。

我在名为WaveNative的包装类中使用mmdll库：

// native calls
[DllImport(mmdll)]
public static extern int waveOutGetNumDevs();
[DllImport(mmdll)]
public static extern int waveOutPrepareHeader(IntPtr hWaveOut, ref WaveHdr lpWaveOutHdr, int uSize);
[DllImport(mmdll)]
public static extern int waveOutUnprepareHeader(IntPtr hWaveOut, ref WaveHdr lpWaveOutHdr, int uSize);
[DllImport(mmdll)]
public static extern int waveOutWrite(IntPtr hWaveOut, ref WaveHdr lpWaveOutHdr, int uSize);
[DllImport(mmdll)]
public static extern int waveOutOpen(out IntPtr hWaveOut, int uDeviceID, WaveFormat lpFormat, WaveDelegate dwCallback, int dwInstance, int dwFlags);
[DllImport(mmdll)]
public static extern int waveOutReset(IntPtr hWaveOut);
[DllImport(mmdll)]
public static extern int waveOutClose(IntPtr hWaveOut);
[DllImport(mmdll)]
public static extern int waveOutPause(IntPtr hWaveOut);
[DllImport(mmdll)]
public static extern int waveOutRestart(IntPtr hWaveOut);
[DllImport(mmdll)]
public static extern int waveOutGetPosition(IntPtr hWaveOut, out int lpInfo, int uSize);
[DllImport(mmdll)]
public static extern int waveOutSetVolume(IntPtr hWaveOut, int dwVolume);
[DllImport(mmdll)]
public static extern int waveOutGetVolume(IntPtr hWaveOut, out int dwVolume);

现在我通过调用以下方式打开设备：

int msg = WaveNative.waveOutOpen(out myWaveOutHandleAsIntPtr, device, waveformatOfAudioFile, callbackDelegate, 0, WaveNative.CALLBACK_FUNCTION);

这有效，我可以将音频数据写入设备。但：当声音播放完毕后，我等待回调方法发出信号表示我所有的音频缓冲区（我有2个，每个8192个字节）已经完成播放：

// Inside the callback method:
if (callbackswaiting > 0)
{
    callbackswaiting--;
    if(callbackswaiting == 0)
    {
        WaveNative.waveOutReset(myWaveOutHandleAsIntPtr);
        WaveNative.waveOutClose(myWaveOutHandleAsIntPtr);
    }
}

现在，只要我再次尝试调用waveOutOpen（）方法，我的程序就会挂起。它不会返回任何错误，只是挂起。

我做错了什么？

waveOutOpen在C＃中的waveOutClose之后挂起

0 个答案: