/// <summary>
/// Stop recording audio and save it to destination WAV-file
/// </summary>
/// <param name="destination">Output WAV file containing recorderd sound</param>
public void StopRecording(string destination)
{
var mciCommand = "stop capture";
Mci.SendString(mciCommand, null, 0, 0);
mciCommand = string.Format("save capture {0}", destination);
Mci.SendString(mciCommand, null, 0, 0);
mciCommand = "close capture";
Mci.SendString(mciCommand, null, 0, 0);
}
/// <summary>
/// Pause audio playback
/// </summary>
public void Pause()
{
if (_alias == null)
{
return;
}
var mciCommand = string.Format("pause {0}", _alias);
Mci.SendString(mciCommand, null, 0, 0);
_pauseTime = DateTime.Now;
_isPaused = true;
}
/// <summary>
/// Resume playing audio
/// </summary>
public void Resume()
{
if (_alias == null || !_isPaused)
{
return;
}
var mciCommand = string.Format("resume {0}", _alias);
Mci.SendString(mciCommand, null, 0, 0);
var pause = DateTime.Now - _pauseTime;
_pauseDuration += pause.Duration().Seconds * 1000 + pause.Duration().Milliseconds;
_isPaused = false;
}
/// <summary>
/// Pauses playing audio.
/// </summary>
public void Pause()
{
if (_alias is null)
{
return;
}
var mciCommand = string.Format("pause {0}", _alias);
Mci.SendString(mciCommand, null, 0, 0);
// If the playback was paused, the player memorizes how many milliseconds
// it was "idle" and then adds this time to the total awaiting time.
_pauseTime = DateTime.Now;
_isPaused = true;
}
/// <summary>
/// Stop playing audio and close MCI device
/// </summary>
public void Stop()
{
if (_alias == null)
{
return;
}
if (_isPaused)
{
Resume();
}
var mciCommand = string.Format("stop {0}", _alias);
Mci.SendString(mciCommand, null, 0, 0);
mciCommand = string.Format("close {0}", _alias);
Mci.SendString(mciCommand, null, 0, 0);
_alias = null;
}
/// <summary>
/// Start recording audio with specific settings
/// </summary>
/// <param name="samplingRate">Sampling rate</param>
/// <param name="channelCount">Number of channels (1=mono, 2=stereo)</param>
/// <param name="bitsPerSample">Number of bits per sample (8, 16, 24 or 32)</param>
public void StartRecording(int samplingRate = 44100, short channelCount = 1, short bitsPerSample = 16)
{
var mciCommand = "open new type waveaudio alias capture";
var result = Mci.SendString(mciCommand, null, 0, 0);
if (result != 0)
{
throw new System.InvalidOperationException("Could not open device for recording!");
}
mciCommand = string.Format("set capture alignment {0} bitspersample {1} samplespersec {2} " +
"channels {3} bytespersec {4} time format samples format tag pcm",
channelCount * bitsPerSample / 8,
bitsPerSample,
samplingRate,
channelCount,
samplingRate * channelCount * bitsPerSample / 8);
Mci.SendString(mciCommand, null, 0, 0);
mciCommand = "record capture";
Mci.SendString(mciCommand, null, 0, 0);
}
/// <summary>
/// Play audio contained in WAV file asynchronously
/// </summary>
/// <param name="source">WAV file to play</param>
/// <param name="startPos">Number of the first sample to play</param>
/// <param name="endPos">Number of the last sample to play</param>
public async Task PlayAsync(string source, int startPos = 0, int endPos = -1)
{
if (_isPaused)
{
Resume();
return;
}
Stop();
_alias = Guid.NewGuid().ToString();
var mciCommand = string.Format("open \"{0}\" type waveaudio alias {1}", source, _alias);
Mci.SendString(mciCommand, null, 0, 0);
mciCommand = string.Format("set {0} time format samples", _alias);
Mci.SendString(mciCommand, null, 0, 0);
var durationBuffer = new StringBuilder(255);
mciCommand = string.Format("status {0} length", _alias);
Mci.SendString(mciCommand, durationBuffer, 255, 0);
var duration = int.Parse(durationBuffer.ToString());
var samplingRateBuffer = new StringBuilder(255);
mciCommand = string.Format("status {0} samplespersec", _alias);
Mci.SendString(mciCommand, samplingRateBuffer, 255, 0);
var samplingRate = int.Parse(samplingRateBuffer.ToString());
mciCommand = string.Format("play {2} from {0} to {1} notify", startPos, endPos, _alias);
mciCommand = mciCommand.Replace(" to -1", "");
Mci.SendString(mciCommand, null, 0, 0);
// ======= here's how we do asynchrony with old technology from 90's )) ========
var currentAlias = _alias;
await Task.Delay((int)(duration * 1000.0 / samplingRate));
// During this time someone could Pause player.
// In this case we add pause duration to awaiting time.
while (_isPaused || _pauseDuration > 0)
{
// first, we check if the pause is right now
if (_isPaused)
{
// then just await one second more
// (the stupidest wait spin I wrote in years ))))
await Task.Delay(1000);
}
if (_pauseDuration > 0)
{
await Task.Delay(_pauseDuration);
_pauseDuration = 0;
}
}
// During this time someone could stop and run player again, so _alias is already different.
// In this case we don't stop player here because it was stopped some time before.
if (currentAlias == _alias)
{
Stop();
}
// =============================================================================
}
