neilt6/AudioTrackOut.cs

## AudioTrackOut.cs
using Android.Media;
using NAudio.Wave;
using System;
using System.Threading;

namespace NAudio.Wave
{
    /// <summary>
    /// Represents an Android wave player implemented using <see cref="AudioTrack"/>.
    /// </summary>
    public class AudioTrackOut : IWavePlayer
    {
        #region Fields

        IWaveProvider m_WaveProvider;
        AudioTrack m_AudioTrack;
        Thread m_PlaybackThread;
        float m_Volume;
        bool m_IsDisposed;

        #endregion

        #region Properties

        /// <summary>
        /// Gets the current playback state.
        /// </summary>
        public PlaybackState PlaybackState { get; private set; }

        /// <summary>
        /// Gets or sets the volume in % (0.0 to 1.0).
        /// </summary>
        public float Volume
        {
            get => m_Volume;
            set
            {
                m_Volume = (value < 0.0f) ? 0.0f : (value > 1.0f) ? 1.0f : value;
                m_AudioTrack?.SetVolume(m_Volume);
            }
        }

        /// <summary>
        /// Gets or sets the desired latency in milliseconds.
        /// </summary>
        public int DesiredLatency { get; set; }

        /// <summary>
        /// Gets or sets the number of buffers to use.
        /// </summary>
        public int NumberOfBuffers { get; set; }

        /// <summary>
        /// Gets or sets the usage.
        /// </summary>
        public AudioUsageKind Usage { get; set; }

        /// <summary>
        /// Gets or sets the content type.
        /// </summary>
        public AudioContentType ContentType { get; set; }

        /// <summary>
        /// Gets or sets the performance mode.
        /// </summary>
        public AudioTrackPerformanceMode PerformanceMode { get; set; }

        #endregion

        #region Events

        /// <summary>
        /// Occurs when the player has stopped.
        /// </summary>
        public event EventHandler<StoppedEventArgs> PlaybackStopped;

        #endregion

        #region Constructors

        /// <summary>
        /// Initializes a new instance of the <see cref="AudioTrackOut"/> class.
        /// </summary>
        public AudioTrackOut()
        {
            //Initialize the fields and properties
            m_WaveProvider = null;
            m_AudioTrack = null;
            m_PlaybackThread = null;
            m_Volume = 1.0f;
            m_IsDisposed = false;
            PlaybackState = PlaybackState.Stopped;
            DesiredLatency = 300;
            NumberOfBuffers = 2;
            Usage = AudioUsageKind.Media;
            ContentType = AudioContentType.Music;
            PerformanceMode = AudioTrackPerformanceMode.None;
        }

        /// <summary>
        /// Releases the unmanaged resources used by the current instance of the <see cref="AudioTrackOut"/> class.
        /// </summary>
        ~AudioTrackOut()
        {
            //Dispose of this object
            Dispose(false);
        }

        #endregion

        #region Public Methods

        /// <summary>
        /// Initializes the player with the specified wave provider.
        /// </summary>
        /// <param name="waveProvider">The wave provider to be played.</param>
        public void Init(IWaveProvider waveProvider)
        {
            //Make sure we haven't been disposed
            ThrowIfDisposed();

            //Check the player state
            if (m_WaveProvider != null)
            {
                throw new InvalidOperationException("This wave player instance has already been initialized");
            }

            //Initialize the wave provider
            Encoding encoding;
            if (waveProvider == null)
            {
                throw new ArgumentNullException(nameof(waveProvider));
            }
            else if (waveProvider.WaveFormat.Encoding == WaveFormatEncoding.Pcm || waveProvider.WaveFormat.Encoding == WaveFormatEncoding.IeeeFloat)
            {
                encoding = waveProvider.WaveFormat.BitsPerSample switch
                {
                    8 => Encoding.Pcm8bit,
                    16 => Encoding.Pcm16bit,
                    32 => Encoding.PcmFloat,
                    _ => throw new ArgumentException("Input wave provider must be 8-bit, 16-bit, or 32-bit", nameof(waveProvider))
                };
            }
            else
            {
                throw new ArgumentException("Input wave provider must be PCM or IEEE float", nameof(waveProvider));
            }
            m_WaveProvider = waveProvider;

            //Determine the channel mask
            ChannelOut channelMask = m_WaveProvider.WaveFormat.Channels switch
            {
                1 => ChannelOut.Mono,
                2 => ChannelOut.Stereo,
                _ => throw new ArgumentException("Input wave provider must be mono or stereo", nameof(waveProvider))
            };

            //Determine the buffer size
            int minBufferSize = AudioTrack.GetMinBufferSize(m_WaveProvider.WaveFormat.SampleRate, channelMask, encoding);
            int bufferSize = m_WaveProvider.WaveFormat.ConvertLatencyToByteSize(DesiredLatency);
            if (bufferSize < minBufferSize)
            {
                bufferSize = minBufferSize;
            }

            //Initialize the audio track
            m_AudioTrack = new AudioTrack.Builder()
                .SetAudioAttributes(new AudioAttributes.Builder()
                    .SetUsage(Usage)
                    .SetContentType(ContentType)
                    .Build())
                .SetAudioFormat(new AudioFormat.Builder()
                    .SetEncoding(encoding)
                    .SetSampleRate(m_WaveProvider.WaveFormat.SampleRate)
                    .SetChannelMask(channelMask)
                    .Build())
                .SetBufferSizeInBytes(bufferSize)
                .SetTransferMode(AudioTrackMode.Stream)
                .SetPerformanceMode(PerformanceMode)
                .Build();
            m_AudioTrack.SetVolume(Volume);
        }

        /// <summary>
        /// Starts the player.
        /// </summary>
        public void Play()
        {
            //Make sure we haven't been disposed
            ThrowIfDisposed();

            //Check the player state
            ThrowIfNotInitialized();
            if (PlaybackState == PlaybackState.Playing)
            {
                return;
            }

            //Start the wave player
            PlaybackState = PlaybackState.Playing;
            m_AudioTrack.Play();
            if (m_PlaybackThread == null || !m_PlaybackThread.IsAlive)
            {
                m_PlaybackThread = new Thread(PlaybackThread);
                m_PlaybackThread.Priority = ThreadPriority.Highest;
                m_PlaybackThread.Start();
            }
        }

        /// <summary>
        /// Pauses the player.
        /// </summary>
        public void Pause()
        {
            //Make sure we haven't been disposed
            ThrowIfDisposed();

            //Check the player state
            ThrowIfNotInitialized();
            if (PlaybackState == PlaybackState.Stopped || PlaybackState == PlaybackState.Paused)
            {
                return;
            }

            //Pause the wave player
            PlaybackState = PlaybackState.Paused;
            m_AudioTrack.Pause();
        }

        /// <summary>
        /// Stops the player.
        /// </summary>
        public void Stop()
        {
            //Make sure we haven't been disposed
            ThrowIfDisposed();

            //Check the player state
            ThrowIfNotInitialized();
            if (PlaybackState == PlaybackState.Stopped)
            {
                return;
            }

            //Stop the wave player
            PlaybackState = PlaybackState.Stopped;
            m_AudioTrack.Stop();
            m_PlaybackThread.Join();
        }

        /// <summary>
        /// Releases all resources used by the current instance of the <see cref="AudioTrackOut"/> class.
        /// </summary>
        public void Dispose()
        {
            //Dispose of this object
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        #endregion

        #region Protected Methods

        /// <summary>
        /// Raises the <see cref="PlaybackStopped"/> event with the provided arguments.
        /// </summary>
        /// <param name="exception">An optional exception that occured.</param>
        protected virtual void OnPlaybackStopped(Exception exception = null)
        {
            //Raise the playback stopped event
            PlaybackStopped?.Invoke(this, new StoppedEventArgs(exception));
        }

        /// <summary>
        /// Releases the unmanaged resources used by the <see cref="AudioTrackOut"/>, and optionally releases the managed resources.
        /// </summary>
        /// <param name="disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
        protected virtual void Dispose(bool disposing)
        {
            //Clean up any managed and unmanaged resources
            if (!m_IsDisposed)
            {
                if (disposing)
                {
                    if (PlaybackState != PlaybackState.Stopped)
                    {
                        Stop();
                    }
                    m_AudioTrack?.Release();
                    m_AudioTrack?.Dispose();
                }
                m_IsDisposed = true;
            }
        }

        #endregion

        #region Private Methods

        private void PlaybackThread()
        {
            //Run the playback logic
            Exception exception = null;
            try
            {
                PlaybackLogic();
            }
            catch (Exception e)
            {
                exception = e;
            }
            finally
            {
                PlaybackState = PlaybackState.Stopped;
                OnPlaybackStopped(exception);
            }
        }

        private void PlaybackLogic()
        {
            //Initialize the wave buffer
            int waveBufferSize = (m_AudioTrack.BufferSizeInFrames + NumberOfBuffers - 1) / NumberOfBuffers * m_WaveProvider.WaveFormat.BlockAlign;
            waveBufferSize = (waveBufferSize + 3) & ~3;
            WaveBuffer waveBuffer = new WaveBuffer(waveBufferSize);
            waveBuffer.ByteBufferCount = waveBufferSize;

            //Run the playback loop
            while (PlaybackState != PlaybackState.Stopped)
            {
                //Check the playback state
                if (PlaybackState != PlaybackState.Playing)
                {
                    Thread.Sleep(10);
                    continue;
                }

                //Fill the wave buffer with new samples
                int bytesRead = m_WaveProvider.Read(waveBuffer.ByteBuffer, 0, waveBuffer.ByteBufferCount);
                if (bytesRead > 0)
                {
                    //Clear the unused space in the wave buffer if necessary
                    if (bytesRead < waveBuffer.ByteBufferCount)
                    {
                        waveBuffer.ByteBufferCount = (bytesRead + 3) & ~3;
                        Array.Clear(waveBuffer.ByteBuffer, bytesRead, waveBuffer.ByteBufferCount - bytesRead);
                    }

                    //Write the wave buffer to the audio track
                    WriteBuffer(waveBuffer);
                }
                else
                {
                    //Stop the audio track
                    m_AudioTrack.Stop();
                    break;
                }
            }

            //Flush the audio track
            m_AudioTrack.Flush();
        }

        private void WriteBuffer(IWaveBuffer waveBuffer)
        {
            //Write the specified wave buffer to the audio track
            if (m_WaveProvider.WaveFormat.Encoding == WaveFormatEncoding.Pcm)
            {
                m_AudioTrack.Write(waveBuffer.ByteBuffer, 0, waveBuffer.ByteBufferCount);
            }
            else if (m_WaveProvider.WaveFormat.Encoding == WaveFormatEncoding.IeeeFloat)
            {
                //AudioTrack.Write doesn't appreciate WaveBuffer.FloatBuffer
                float[] floatBuffer = new float[waveBuffer.FloatBufferCount];
                for (int i = 0; i < waveBuffer.FloatBufferCount; i++)
                {
                    floatBuffer[i] = waveBuffer.FloatBuffer[i];
                }
                m_AudioTrack.Write(floatBuffer, 0, floatBuffer.Length, WriteMode.Blocking);
            }
        }

        private void ThrowIfNotInitialized()
        {
            //Throw an exception if this object has not been initialized
            if (m_WaveProvider == null)
            {
                throw new InvalidOperationException("This wave player instance has not been initialized");
            }
        }

        private void ThrowIfDisposed()
        {
            //Throw an exception if this object has been disposed
            if (m_IsDisposed)
            {
                throw new ObjectDisposedException(GetType().FullName);
            }
        }

        #endregion
    }
}
	using Android.Media;
	using NAudio.Wave;
	using System;
	using System.Threading;

	namespace NAudio.Wave
	{
	/// <summary>
	/// Represents an Android wave player implemented using <see cref="AudioTrack"/>.
	/// </summary>
	public class AudioTrackOut : IWavePlayer
	{
	#region Fields

	IWaveProvider m_WaveProvider;
	AudioTrack m_AudioTrack;
	Thread m_PlaybackThread;
	float m_Volume;
	bool m_IsDisposed;

	#endregion

	#region Properties

	/// <summary>
	/// Gets the current playback state.
	/// </summary>
	public PlaybackState PlaybackState { get; private set; }

	/// <summary>
	/// Gets or sets the volume in % (0.0 to 1.0).
	/// </summary>
	public float Volume
	{
	get => m_Volume;
	set
	{
	m_Volume = (value < 0.0f) ? 0.0f : (value > 1.0f) ? 1.0f : value;
	m_AudioTrack?.SetVolume(m_Volume);
	}
	}

	/// <summary>
	/// Gets or sets the desired latency in milliseconds.
	/// </summary>
	public int DesiredLatency { get; set; }

	/// <summary>
	/// Gets or sets the number of buffers to use.
	/// </summary>
	public int NumberOfBuffers { get; set; }

	/// <summary>
	/// Gets or sets the usage.
	/// </summary>
	public AudioUsageKind Usage { get; set; }

	/// <summary>
	/// Gets or sets the content type.
	/// </summary>
	public AudioContentType ContentType { get; set; }

	/// <summary>
	/// Gets or sets the performance mode.
	/// </summary>
	public AudioTrackPerformanceMode PerformanceMode { get; set; }

	#endregion

	#region Events

	/// <summary>
	/// Occurs when the player has stopped.
	/// </summary>
	public event EventHandler<StoppedEventArgs> PlaybackStopped;

	#endregion

	#region Constructors

	/// <summary>
	/// Initializes a new instance of the <see cref="AudioTrackOut"/> class.
	/// </summary>
	public AudioTrackOut()
	{
	//Initialize the fields and properties
	m_WaveProvider = null;
	m_AudioTrack = null;
	m_PlaybackThread = null;
	m_Volume = 1.0f;
	m_IsDisposed = false;
	PlaybackState = PlaybackState.Stopped;
	DesiredLatency = 300;
	NumberOfBuffers = 2;
	Usage = AudioUsageKind.Media;
	ContentType = AudioContentType.Music;
	PerformanceMode = AudioTrackPerformanceMode.None;
	}

	/// <summary>
	/// Releases the unmanaged resources used by the current instance of the <see cref="AudioTrackOut"/> class.
	/// </summary>
	~AudioTrackOut()
	{
	//Dispose of this object
	Dispose(false);
	}

	#endregion

	#region Public Methods

	/// <summary>
	/// Initializes the player with the specified wave provider.
	/// </summary>
	/// <param name="waveProvider">The wave provider to be played.</param>
	public void Init(IWaveProvider waveProvider)
	{
	//Make sure we haven't been disposed
	ThrowIfDisposed();

	//Check the player state
	if (m_WaveProvider != null)
	{
	throw new InvalidOperationException("This wave player instance has already been initialized");
	}

	//Initialize the wave provider
	Encoding encoding;
	if (waveProvider == null)
	{
	throw new ArgumentNullException(nameof(waveProvider));
	}
	else if (waveProvider.WaveFormat.Encoding == WaveFormatEncoding.Pcm \|\| waveProvider.WaveFormat.Encoding == WaveFormatEncoding.IeeeFloat)
	{
	encoding = waveProvider.WaveFormat.BitsPerSample switch
	{
	8 => Encoding.Pcm8bit,
	16 => Encoding.Pcm16bit,
	32 => Encoding.PcmFloat,
	_ => throw new ArgumentException("Input wave provider must be 8-bit, 16-bit, or 32-bit", nameof(waveProvider))
	};
	}
	else
	{
	throw new ArgumentException("Input wave provider must be PCM or IEEE float", nameof(waveProvider));
	}
	m_WaveProvider = waveProvider;

	//Determine the channel mask
	ChannelOut channelMask = m_WaveProvider.WaveFormat.Channels switch
	{
	1 => ChannelOut.Mono,
	2 => ChannelOut.Stereo,
	_ => throw new ArgumentException("Input wave provider must be mono or stereo", nameof(waveProvider))
	};

	//Determine the buffer size
	int minBufferSize = AudioTrack.GetMinBufferSize(m_WaveProvider.WaveFormat.SampleRate, channelMask, encoding);
	int bufferSize = m_WaveProvider.WaveFormat.ConvertLatencyToByteSize(DesiredLatency);
	if (bufferSize < minBufferSize)
	{
	bufferSize = minBufferSize;
	}

	//Initialize the audio track
	m_AudioTrack = new AudioTrack.Builder()
	.SetAudioAttributes(new AudioAttributes.Builder()
	.SetUsage(Usage)
	.SetContentType(ContentType)
	.Build())
	.SetAudioFormat(new AudioFormat.Builder()
	.SetEncoding(encoding)
	.SetSampleRate(m_WaveProvider.WaveFormat.SampleRate)
	.SetChannelMask(channelMask)
	.Build())
	.SetBufferSizeInBytes(bufferSize)
	.SetTransferMode(AudioTrackMode.Stream)
	.SetPerformanceMode(PerformanceMode)
	.Build();
	m_AudioTrack.SetVolume(Volume);
	}

	/// <summary>
	/// Starts the player.
	/// </summary>
	public void Play()
	{
	//Make sure we haven't been disposed
	ThrowIfDisposed();

	//Check the player state
	ThrowIfNotInitialized();
	if (PlaybackState == PlaybackState.Playing)
	{
	return;
	}

	//Start the wave player
	PlaybackState = PlaybackState.Playing;
	m_AudioTrack.Play();
	if (m_PlaybackThread == null \|\| !m_PlaybackThread.IsAlive)
	{
	m_PlaybackThread = new Thread(PlaybackThread);
	m_PlaybackThread.Priority = ThreadPriority.Highest;
	m_PlaybackThread.Start();
	}
	}

	/// <summary>
	/// Pauses the player.
	/// </summary>
	public void Pause()
	{
	//Make sure we haven't been disposed
	ThrowIfDisposed();

	//Check the player state
	ThrowIfNotInitialized();
	if (PlaybackState == PlaybackState.Stopped \|\| PlaybackState == PlaybackState.Paused)
	{
	return;
	}

	//Pause the wave player
	PlaybackState = PlaybackState.Paused;
	m_AudioTrack.Pause();
	}

	/// <summary>
	/// Stops the player.
	/// </summary>
	public void Stop()
	{
	//Make sure we haven't been disposed
	ThrowIfDisposed();

	//Check the player state
	ThrowIfNotInitialized();
	if (PlaybackState == PlaybackState.Stopped)
	{
	return;
	}

	//Stop the wave player
	PlaybackState = PlaybackState.Stopped;
	m_AudioTrack.Stop();
	m_PlaybackThread.Join();
	}

	/// <summary>
	/// Releases all resources used by the current instance of the <see cref="AudioTrackOut"/> class.
	/// </summary>
	public void Dispose()
	{
	//Dispose of this object
	Dispose(true);
	GC.SuppressFinalize(this);
	}

	#endregion

	#region Protected Methods

	/// <summary>
	/// Raises the <see cref="PlaybackStopped"/> event with the provided arguments.
	/// </summary>
	/// <param name="exception">An optional exception that occured.</param>
	protected virtual void OnPlaybackStopped(Exception exception = null)
	{
	//Raise the playback stopped event
	PlaybackStopped?.Invoke(this, new StoppedEventArgs(exception));
	}

	/// <summary>
	/// Releases the unmanaged resources used by the <see cref="AudioTrackOut"/>, and optionally releases the managed resources.
	/// </summary>
	/// <param name="disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
	protected virtual void Dispose(bool disposing)
	{
	//Clean up any managed and unmanaged resources
	if (!m_IsDisposed)
	{
	if (disposing)
	{
	if (PlaybackState != PlaybackState.Stopped)
	{
	Stop();
	}
	m_AudioTrack?.Release();
	m_AudioTrack?.Dispose();
	}
	m_IsDisposed = true;
	}
	}

	#endregion

	#region Private Methods

	private void PlaybackThread()
	{
	//Run the playback logic
	Exception exception = null;
	try
	{
	PlaybackLogic();
	}
	catch (Exception e)
	{
	exception = e;
	}
	finally
	{
	PlaybackState = PlaybackState.Stopped;
	OnPlaybackStopped(exception);
	}
	}

	private void PlaybackLogic()
	{
	//Initialize the wave buffer
	int waveBufferSize = (m_AudioTrack.BufferSizeInFrames + NumberOfBuffers - 1) / NumberOfBuffers * m_WaveProvider.WaveFormat.BlockAlign;
	waveBufferSize = (waveBufferSize + 3) & ~3;
	WaveBuffer waveBuffer = new WaveBuffer(waveBufferSize);
	waveBuffer.ByteBufferCount = waveBufferSize;

	//Run the playback loop
	while (PlaybackState != PlaybackState.Stopped)
	{
	//Check the playback state
	if (PlaybackState != PlaybackState.Playing)
	{
	Thread.Sleep(10);
	continue;
	}

	//Fill the wave buffer with new samples
	int bytesRead = m_WaveProvider.Read(waveBuffer.ByteBuffer, 0, waveBuffer.ByteBufferCount);
	if (bytesRead > 0)
	{
	//Clear the unused space in the wave buffer if necessary
	if (bytesRead < waveBuffer.ByteBufferCount)
	{
	waveBuffer.ByteBufferCount = (bytesRead + 3) & ~3;
	Array.Clear(waveBuffer.ByteBuffer, bytesRead, waveBuffer.ByteBufferCount - bytesRead);
	}

	//Write the wave buffer to the audio track
	WriteBuffer(waveBuffer);
	}
	else
	{
	//Stop the audio track
	m_AudioTrack.Stop();
	break;
	}
	}

	//Flush the audio track
	m_AudioTrack.Flush();
	}

	private void WriteBuffer(IWaveBuffer waveBuffer)
	{
	//Write the specified wave buffer to the audio track
	if (m_WaveProvider.WaveFormat.Encoding == WaveFormatEncoding.Pcm)
	{
	m_AudioTrack.Write(waveBuffer.ByteBuffer, 0, waveBuffer.ByteBufferCount);
	}
	else if (m_WaveProvider.WaveFormat.Encoding == WaveFormatEncoding.IeeeFloat)
	{
	//AudioTrack.Write doesn't appreciate WaveBuffer.FloatBuffer
	float[] floatBuffer = new float[waveBuffer.FloatBufferCount];
	for (int i = 0; i < waveBuffer.FloatBufferCount; i++)
	{
	floatBuffer[i] = waveBuffer.FloatBuffer[i];
	}
	m_AudioTrack.Write(floatBuffer, 0, floatBuffer.Length, WriteMode.Blocking);
	}
	}

	private void ThrowIfNotInitialized()
	{
	//Throw an exception if this object has not been initialized
	if (m_WaveProvider == null)
	{
	throw new InvalidOperationException("This wave player instance has not been initialized");
	}
	}

	private void ThrowIfDisposed()
	{
	//Throw an exception if this object has been disposed
	if (m_IsDisposed)
	{
	throw new ObjectDisposedException(GetType().FullName);
	}
	}

	#endregion
	}
	}