问ByteStream源在SharpDX.MediaFoundation悬挂中的应用

EN

public class AudioReaderWaveStream : System.IO.Stream
{
    byte[] waveHeader = new byte[44];
    AudioCore.IAudioReader reader = null;
    ulong readHandle = 0xffffffff;

    long readPosition = 0;

    public AudioReaderWaveStream(AudioCore.CEditedAudio content)
    {
        reader = content as AudioCore.IAudioReader;
        readHandle = reader.OpenDevice();

        int sampleRate = 0;
        short channels = 0;
        content.GetFormat(out sampleRate, out channels);

        System.IO.MemoryStream memStream = new System.IO.MemoryStream(waveHeader);
        using (System.IO.BinaryWriter bw = new System.IO.BinaryWriter(memStream))
        {
            bw.Write("RIFF".ToCharArray());
            bw.Write((Int32)Length - 8);
            bw.Write("WAVE".ToCharArray());
            bw.Write("fmt ".ToCharArray());
            bw.Write((Int32)16);
            bw.Write((Int16)3);
            bw.Write((Int16)1);
            bw.Write((Int32)sampleRate);
            bw.Write((Int32)sampleRate * 4);
            bw.Write((Int16)4);
            bw.Write((Int16)32);
            bw.Write("data".ToCharArray());
            bw.Write((Int32)reader.GetSampleCount() * 4);
        }
    }

    protected override void Dispose(bool disposing)
    {
        if (readHandle != 0xffffffff)
        {
            reader.CloseDevice(readHandle);
            readHandle = 0xfffffffff;
        }
        base.Dispose(disposing);
    }

    ~AudioReaderWaveStream()
    {
        Dispose();
    }

    public override bool CanRead
    {
        get
        {
            return true;
        }
    }

    public override bool CanSeek
    {
        get
        {
            return true;
        }
    }

    public override bool CanWrite
    {
        get
        {
            return false;
        }
    }


    public override long Length
    {
        get
        {
            // Number of float samples + header of 44 bytes.
            return (reader.GetSampleCount() * 4) + 44;
        }
    }

    public override long Position
    {
        get
        {
            return readPosition;
        }
        set
        {
            readPosition = value;
        }
    }

    public override void Flush()
    {
        //throw new NotImplementedException();
    }

    public override int Read(byte[] buffer, int offset, int count)
    {
        if (count <= 0)
            return 0;

        int retCount = count;
        if (Position < 44)
        {
            int headerCount = count;
            if ( Position + count >= 44 )
            {
                headerCount = 44 - (int)Position;
            }
            Array.Copy(waveHeader, Position, buffer, offset, headerCount);
            offset += headerCount;
            Position += headerCount;
            count -= headerCount;
        }
        if (count > 0)
        {
            float[] readBuffer = new float[count/4];
            reader.Seek(readHandle, Position - 44);
            reader.ReadAudio(readHandle, readBuffer);

            Array.Copy(readBuffer, 0, buffer, offset, count);
        }
        return retCount;
    }

    public override long Seek(long offset, System.IO.SeekOrigin origin)
    {
        if (origin == System.IO.SeekOrigin.Begin)
        {
            readPosition = offset;
        }
        else if (origin == System.IO.SeekOrigin.Current)
        {
            readPosition += offset;
        }
        else
        {
            readPosition = Length - offset;
        }
        return readPosition;
    }

    public override void SetLength(long value)
    {
        throw new NotImplementedException();
    }

    public override void Write(byte[] buffer, int offset, int count)
    {
        throw new NotImplementedException();
    }
}

// Create a source resolver.
SharpDX.MediaFoundation.ByteStream      sdxByteStream   = new ByteStream( ARWS );
SharpDX.MediaFoundation.SourceResolver  resolver        = new SharpDX.MediaFoundation.SourceResolver();
ComObject                               source          = (ComObject)resolver.CreateObjectFromStream( sdxByteStream, "File.wav",  SourceResolverFlags.MediaSource );