DLL To Decode MP3 To WAV/PCM

Private Sub Command1_Click()

Dim FileNameMP3 As String
Dim FileNameWAV As String
Dim Result As Long
Dim Path As String

Path = "c:\YOURPATH\"
FileNameMP3 = Text1.Text
FileNameWAV = Left(FileNameMP3, Len(FileNameMP3) - 3) & "wav"
Result = Mp3TOWav(Path & FileNameMP3, Path & FileNameWAV, 1, AddressOf StatusMSG, AddressOf MyCallback)
MsgBox "All Done"

End Sub

public partial class Form1 : Form
   {
       [MarshalAs(UnmanagedType.LPStr)] private StringBuilder strBuilder = new StringBuilder("",11000);
       MadlldlibWrapper.Callback updateFunction ;
       string mp3File = "";
       string wavFile = "";
       Boolean bCancel = false;
       OpenFileDialog Dialog = new OpenFileDialog();

       public Form1()
       {
           InitializeComponent();
           updateFunction  = new MadlldlibWrapper.Callback(updateFunctionMethod);
       }

       private Boolean updateFunctionMethod(uint frameCount, uint byteCount,ref Mp3Decoder.MadlldlibWrapper.mad_header madHeader)
       {
           if (frameCount == 1)
           {
               this.label1.Text = "Sampelrate: " + madHeader.samplerate.ToString() +
                   " Bitrate: " + madHeader.bitrate.ToString() +
                   " Duration: " + madHeader.duration +
                   " Layer: " + madHeader.layer.ToString();
               Application.DoEvents();
           }
           this.label3.Text = "frame:= " + frameCount.ToString() + " byte:= " + byteCount.ToString();
           Application.DoEvents();
           if (bCancel) {
               return false;
               }
           else { return true; }
       }


       private void selectMp3ToolStripMenuItem1_Click(object sender, EventArgs e)
       {
           Dialog.Filter = "mp3 files (*.mp3)|*.mp3";
           Dialog.Multiselect = false;
           Dialog.ShowDialog();
           if (Dialog.FileName != "") {
               this.label3.Text = "";
               mp3File = Dialog.FileName;
               this.textBox1.Text = Dialog.FileName;
               wavFile = Dialog.FileName.Remove(Dialog.FileName.LastIndexOf("."), Dialog.FileName.Length - Dialog.FileName.LastIndexOf(".")) + ".wav";
           }
       }

       private void exitToolStripMenuItem_Click(object sender, EventArgs e)
       {
           this.Close();
       }

       private void button1_Click(object sender, EventArgs e)
       {
           MadlldlibWrapper.DecodeMP3(mp3File, wavFile, 1, strBuilder, updateFunction);
           this.label3.Text = "Conversion done!";
       }

       private void button2_Click(object sender, EventArgs e)
       {
           this.bCancel = true;
       }
   }

namespace Mp3Decoder
{
	using System;
	using System.Text;	
	using System.Runtime.InteropServices;

	// Alias; see SF_INFO struct:

	using sf_count_t = System.Int64;	

	
#if PLATFORM_64
	using size_t = System.UInt64;
#else
	using size_t = System.UInt32;
#endif
	

	class MadlldlibWrapper
	{


		// Type declarations hence

		public enum mad_layer : int 
		{
			MAD_LAYER_I   = 1,          // Layer I 
			MAD_LAYER_II  = 2,          // Layer II 
			MAD_LAYER_III = 3           // Layer III 
		};

		
		public enum mad_mode : int 
		{
			MAD_MODE_SINGLE_CHANNEL = 0,      // Single channel 
			MAD_MODE_DUAL_CHANNEL   = 1,      // Dual channel 
			MAD_MODE_JOINT_STEREO   = 2,      // Joint (MS/intensity) stereo 
			MAD_MODE_STEREO         = 3       // Normal LR stereo 
		};
		

		public enum mad_emphasis : int 
		{
			MAD_EMPHASIS_NONE	      = 0,        // No emphasis 
			MAD_EMPHASIS_50_15_US	  = 1,        // 50/15 microsecs emphasis 
			MAD_EMPHASIS_CCITT_J_17   = 3,        // CCITT J.17 emphasis 
			MAD_EMPHASIS_RESERVED     = 2         // Unknown emphasis 
		};


		public struct mad_timer_t 
		{
		  long seconds;     // Whole seconds 
		  uint fraction;    // 1/MAD_TIMER_RESOLUTION seconds 
		};
		

		[StructLayout(LayoutKind.Sequential), Serializable]	
		public struct mad_header 
		{
			public mad_layer layer;             // Audio layer (1, 2, or 3) 
			public mad_mode mode;               // Channel mode 
			public int mode_extension;          // Additional mode info 
			public mad_emphasis emphasis;       // De-emphasis to use

			public uint bitrate;                // Stream bitrate (bps) 
			public uint samplerate;             // Sampling frequency (Hz) 

			public ushort crc_check;            // Frame CRC accumulator 
			public ushort crc_target;           // Final target CRC checksum 

			public int flags;                   // Flags 
			public int private_bits;            // Private bits 

			public mad_timer_t duration;        // Audio playing time of frame 
		};


		// Decoding flags

		public const int DEC_WAV = 1;
		public const int DEC_PCM = 0;



		// Method declarations hence		
		
		
		
		// Callback function is used to pass values
		// related to the decoding process back to
		// the calling code. Use return value to 
		// cancel conversion (set to false)

		public delegate bool 
		Callback( uint frameCount,  uint byteCount, 
				ref mad_header madHeader);	
		
		
		// Conversion routine referencing callback--
		// see madlldlib.cpp source for details about 
		// this function

		[DllImport("madlldlib.dll",	EntryPoint = "CbMpegAudioDecoder")]
		public static extern int 
		DecodeMP3(
				string inFile,
				string outFile,
				int decodeType,				// WAV or PCM
				// Marshalled status message:
				[MarshalAs(UnmanagedType.LPStr)] StringBuilder statmsg,
				Callback updateFunction			// Callback function
				);
	

	} 

	
}