音频数据编解码——在.NET中使用Speex（附下载）

#include  " speex\speex.h "
#include  < windows.h >
#include  < stdio.h >
#include  < stdlib.h >

#include  " speex/speex_echo.h "
#include  " speex/speex_preprocess.h "  
#include  " Speex.h "

#define  FRAME_SIZE 160

float  encoder_input[FRAME_SIZE];
void   * encoder_state;
SpeexBits encoder_bits;

BOOL APIENTRY DllMain( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved
                     )
{
     return  TRUE;
}

 

    ///   <summary>
     ///  对Speex的C#封装。
     ///  zhuweisky 2010.05.13
     ///   </summary>
     public   class  Speex :IAudioCodec
    {
         private   const   int  FrameSize  =   160 ;

         #region  IsDisposed
         private   volatile   bool  isDisposed  =   false ;
         public   bool  IsDisposed
        {
             get  {  return  isDisposed; }
        } 
         #endregion

         #region  Ctor
         ///   <summary>
         ///  初始化。
         ///   </summary>
         ///   <param name="quality"> 编码质量，取值0~10 </param>
         public  Speex( int  quality)
        {
             if  (quality  <   0   ||  quality  >   10 )
            {
                 throw   new  Exception( " quality value must be between 0 and 10. " );
            }

            Speex.encoder_init(quality);
            Speex.decoder_init();
        }
         #endregion

         #region  Dispose
         public   void  Dispose()
        {
             this .isDisposed  =   true ;
            System.Threading.Thread.Sleep( 100 );
            Speex.decoder_dispose();
            Speex.encoder_dispose();
        }
         #endregion

         #region  Encode
         ///   <summary>
         ///  将采集到的音频数据进行编码。
         ///   </summary>        
         public   byte [] Encode( byte [] data)
        {
             if  ( this .isDisposed)
            {
                 return   null ;
            }

             if  (data.Length  %  (FrameSize  *   2 )  !=   0 )
            {
                 throw   new  ArgumentException( " Invalid Data Length. " );
            }

             int  nbBytes;
             short [] input  =   new   short [FrameSize];
             byte [] buffer  =   new   byte [ 200 ];
             byte [] output  =   new   byte [ 0 ];
             for  ( int  i  =   0 ; i  <  data.Length  /  (FrameSize  *   2 ); i ++ )
            {
                 for  ( int  j  =   0 ; j  <  input.Length; j ++ )
                {
                    input[j]  =  ( short )(data[i  *  FrameSize  *   2   +  j  *   2 ]  +  data[i  *  FrameSize  *   2   +  j  *   2   +   1 ]  *   0x100 );
                }

                nbBytes  =  Speex.encoder_encode(input, buffer);
                Array.Resize < byte > ( ref  output, output.Length  +  nbBytes  +   sizeof ( int ));
                Array.Copy(buffer,  0 , output, output.Length  -  nbBytes, nbBytes);

                 for  ( int  j  =   0 ; j  <   sizeof ( int ); j ++ )
                {
                    output[output.Length  -  nbBytes  -   sizeof ( int )  +  j]  =  ( byte )(nbBytes  %   0x100 );
                    nbBytes  /=   0x100 ;
                }
            }
             return  output;
        }
         #endregion

         #region  Decode
         ///   <summary>
         ///  将编码后的数据进行解码得到原始的音频数据。
         ///   </summary>       
         public   byte [] Decode( byte [] data)
        {
             if  ( this .isDisposed)
            {
                 return   null ;
            }

             int  nbBytes, index  =   0 ;
             byte [] input;
             short [] buffer  =   new   short [FrameSize];
             byte [] output  =   new   byte [ 0 ];
             while  (index  <  data.Length)
            {
                nbBytes  =   0 ;
                index  +=   sizeof ( int );
                 for  ( int  i  =   1 ; i  <=   sizeof ( int ); i ++ )
                    nbBytes  =  nbBytes  *   0x100   +  data[index  -  i];
                input  =   new   byte [nbBytes];
                Array.Copy(data, index, input,  0 , input.Length);
                index  +=  input.Length;
                Speex.decoder_decode(nbBytes, input, buffer);
                Array.Resize < byte > ( ref  output, output.Length  +  FrameSize  *   2 );
                 for  ( int  i  =   0 ; i  <  FrameSize; i ++ )
                {
                    output[output.Length  -  FrameSize  *   2   +  i  *   2 ]  =  ( byte )(buffer[i]  %   0x100 );
                    output[output.Length  -  FrameSize  *   2   +  i  *   2   +   1 ]  =  ( byte )(buffer[i]  /   0x100 );
                }
            }
             return  output;
        }
         #endregion

         #region  Pinvoke
        [DllImport( " Speex.dll " , EntryPoint  =   " encoder_init " )]
         internal   extern   static   void  encoder_init( int  quality);
        [DllImport( " Speex.dll " , EntryPoint  =   " encoder_dispose " )]
         internal   extern   static   void  encoder_dispose();
        [DllImport( " Speex.dll " , EntryPoint  =   " encoder_encode " )]
         internal   extern   static   int  encoder_encode( short [] data,  byte [] output);
        [DllImport( " Speex.dll " , EntryPoint  =   " decoder_init " )]
         internal   extern   static   void  decoder_init();
        [DllImport( " Speex.dll " , EntryPoint  =   " decoder_dispose " )]
         internal   extern   static   void  decoder_dispose();
        [DllImport( " Speex.dll " , EntryPoint  =   " decoder_decode " )]
         internal   extern   static   void  decoder_decode( int  nbBytes,  byte [] data,  short [] output);      
         #endregion
    }