AudioFormatConverter.cs source code in C# .NET

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/ DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Speech / Src / Internal / Synthesis / AudioFormatConverter.cs / 1 / AudioFormatConverter.cs

                            //------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// History:
//		4/7/2005	[....]		Imported from SES code 
//----------------------------------------------------------------- 

#region Using directives 

using System;
using System.Speech.Synthesis.TtsEngine;
 
#endregion
 
namespace System.Speech.Internal.Synthesis 
{
    ///  
    /// AudioFormatConverter takes its conversion tables from ...\scg\tts\common\vapiio\alaw_ULaw.cpp
    /// 
    internal static class AudioFormatConverter
    { 
        //*******************************************************************
        // 
        // Internal Methods 
        //
        //******************************************************************* 

        #region Internal Methods

        ///  
        /// Finds the converting method based on the specified formats.
        ///  
        /// Reference to the buffer of audio data. 
        /// Audio format that the data will be converted from.
        /// Audio format that the data will be converted to. 
        /// New array with the audio data in requested format.
        static internal short [] Convert (byte [] data, AudioCodec from, AudioCodec to)
        {
            ConvertByteShort cnvDlgt = null; 

            switch (from) 
            { 
                case AudioCodec.PCM8:
                    switch (to) 
                    {
                        case AudioCodec.PCM16: cnvDlgt = new ConvertByteShort (ConvertLinear8LinearByteShort); break;
                    }
                    break; 
                case AudioCodec.PCM16:
                    switch (to) 
                    { 
                        case AudioCodec.PCM16: cnvDlgt = new ConvertByteShort (ConvertLinear2LinearByteShort); break;
                    } 
                    break;

                case AudioCodec.G711U:
                    switch (to) 
                    {
                        case AudioCodec.PCM16: cnvDlgt = new ConvertByteShort (ConvertULaw2Linear); break; 
                    } 
                    break;
                case AudioCodec.G711A: 
                    switch (to)
                    {
                        case AudioCodec.PCM16: cnvDlgt = new ConvertByteShort (ConvertALaw2Linear); break;
                    } 
                    break;
 
                default: 
                    throw new FormatException ();
            } 

            if (cnvDlgt == null)
            {
                throw new FormatException (); 
            }
 
            return cnvDlgt (data, data.Length); 
        }
 
        /// 
        /// Finds the converting method based on the specified formats.
        /// 
        /// Reference to the buffer of audio data. 
        /// Audio format that the data will be converted from.
        /// Audio format that the data will be converted to. 
        /// New array with the audio data in requested format. 
        static internal byte [] Convert (short [] data, AudioCodec from, AudioCodec to)
        { 
            ConvertShortByte cnvDlgt = null;

            switch (from)
            { 
                case AudioCodec.PCM16:
                    switch (to) 
                    { 
                        case AudioCodec.PCM8: cnvDlgt = new ConvertShortByte (ConvertLinear8LinearShortByte); break;
                        case AudioCodec.PCM16: cnvDlgt = new ConvertShortByte (ConvertLinear2LinearShortByte); break; 
                        case AudioCodec.G711U: cnvDlgt = new ConvertShortByte (ConvertLinear2ULaw); break;
                        case AudioCodec.G711A: cnvDlgt = new ConvertShortByte (ConvertLinear2ALaw); break;
                    }
                    break; 

                default: 
                    throw new FormatException (); 
            }
 
            return cnvDlgt (data, data.Length);
        }

#if SPEECHSERVER 
        /// 
        /// Provides a bit rate for specified codec. 
        ///  
        /// Audio format.
        /// Bit rate (bytes per ms). 
        internal static int GetRate (AudioCodec codec)
        {
            switch (codec)
            { 
                case AudioCodec.G711U:
                case AudioCodec.G711A: 
                case AudioCodec.PCM8: 
                    return 8;
                case AudioCodec.PCM16: 
                    return 16;
            }

            throw new ArgumentException (SR.Get(SRID.AudioDeviceFormatError), "codec"); 
        }
 
#endif 
        internal static AudioCodec TypeOf (WAVEFORMATEX format)
        { 
            AudioCodec codec = AudioCodec.Undefined;

            switch ((WaveFormatTag) format.wFormatTag)
            { 
                case WaveFormatTag.WAVE_FORMAT_PCM:
                    switch (format.nBlockAlign / format.nChannels) 
                    { 
                        case 1:
                            codec = AudioCodec.PCM8; 
                            break;
                        case 2:
                            codec = AudioCodec.PCM16;
                            break; 
                    }
                    break; 
 
                case WaveFormatTag.WAVE_FORMAT_ALAW:
                    codec = AudioCodec.G711A; 
                    break;

                case WaveFormatTag.WAVE_FORMAT_MULAW:
                    codec = AudioCodec.G711U; 
                    break;
            } 
 
            return codec;
        } 

        #endregion

        //******************************************************************** 
        //
        // Private Methods 
        // 
        //*******************************************************************
 
        #region Private Methods

        #region Convertors between Linear and ULaw
 
        /// 
        /// This routine converts from 16 bit linear to ULaw by direct access to the conversion table. 
        ///  
        /// Array of 16 bit linear samples.
        /// Size of the data in the array. 
        /// New buffer of 8 bit ULaw samples.
        static internal byte [] ConvertLinear2ULaw (short [] data, int size)
        {
            byte [] newData = new byte [size]; 
            _uLawCompTableCached = _uLawCompTableCached == null ? CalcLinear2ULawTable () : _uLawCompTableCached;
 
            for (int i = 0; i < size; i++) 
            {
                unchecked 
                {
                    // Extend the sign bit for the sample that is constructed from two bytes
                    newData [i] = _uLawCompTableCached [(ushort) data [i] >> 2];
                } 
            }
            return newData; 
        } 

        ///  
        /// This routine converts from ULaw to 16 bit linear by direct access to the conversion table.
        /// 
        /// Array of 8 bit ULaw samples.
        /// Size of the data in the array. 
        /// New buffer of signed 16 bit linear samples
        static internal short [] ConvertULaw2Linear (byte [] data, int size) 
        { 
            short [] newData = new short [size];
            for (int i = 0; i < size; i++) 
            {
                int sample = ULaw_exp_table [data [i]];

                newData [i] = unchecked ((short) sample); 
            }
 
            return newData; 
        }
 
        /// 
        /// This routine converts from linear to ULaw.
        ///
        /// Craig Reese: IDA/Supercomputing Research Center 
        /// Joe Campbell: Department of Defense
        /// 29 September 1989 
        /// 
        /// References:
        /// 1) CCITT Recommendation G.711  (very difficult to follow) 
        /// 2) "A New Digital Technique for Implementation of Any
        ///     Continuous PCM Companding Law," Villeret, Michel,
        ///     et al. 1973 IEEE Int. Conf. on Communications, Vol 1,
        ///     1973, pg. 11.12-11.17 
        /// 3) MIL-STD-188-113,"Interoperability and Performance Standards
        ///     for Analog-to_Digital Conversion Techniques," 
        ///     17 February 1987 
        /// 
        /// New buffer of 8 bit ULaw samples 
        static private byte [] CalcLinear2ULawTable ()
        {
            /*const*/
            bool ZEROTRAP = false;      // turn off the trap as per the MIL-STD 
            const byte uBIAS = 0x84;              // define the add-in bias for 16 bit samples
            const int uCLIP = 32635; 
 
            byte [] table = new byte [((int) UInt16.MaxValue + 1) >> 2];
 
            for (int i = 0; i < UInt16.MaxValue; i += 4)
            {
                short data = unchecked ((short) i);
 
                int sample;
                int sign, exponent, mantissa; 
                byte ULawbyte; 

                unchecked 
                {
                    // Extend the sign bit for the sample that is constructed from two bytes
                    sample = (int) ((data >> 2) << 2);
 
                    // Get the sample into sign-magnitude.
                    sign = (sample >> 8) & 0x80;          // set aside the sign 
                    if (sign != 0) 
                    {
                        sample = -sample; 
                    }
                    if (sample > uCLIP) sample = uCLIP;   // clip the magnitude

                    // Convert from 16 bit linear to ULaw. 
                    sample = sample + uBIAS;
                    exponent = (int) exp_lut_linear2ulaw [(sample >> 7) & 0xFF]; 
                    mantissa = (int) ((sample >> (exponent + 3)) & 0x0F); 

                    ULawbyte = (byte) (~(sign | (exponent << 4) | mantissa)); 
                }

                if (ZEROTRAP)
                { 
                    if (ULawbyte == 0) ULawbyte = 0x02; // optional CCITT trap
                } 
 
                table [i >> 2] = ULawbyte;
            } 

            return table;
        }
 

#if false // keep for reference 
 
        /// 
        /// This routine converts from ULaw to 16 bit linear. 
        ///
        /// Craig Reese: IDA/Supercomputing Research Center
        /// 29 September 1989
        /// 
        /// References:
        /// 1) CCITT Recommendation G.711  (very difficult to follow) 
        /// 2) MIL-STD-188-113,"Interoperability and Performance Standards 
        ///    for Analog-to_Digital Conversion Techniques,"
        ///    17 February 1987 
        /// 
        /// Array of 8 bit ULaw samples.
        /// Size of the data in the array.
        /// New buffer of signed 16 bit linear samples 
        static internal short [] ConvertULaw2Linear (byte [] data, int size)
        { 
            short [] newData = new short [size]; 
            for (int i = 0; i < size; i++)
            { 
                int sign, exponent, mantissa, sample;
                byte ULawbyte;

                unchecked 
                {
                    ULawbyte = (byte) (~data [i]); 
                } 

                sign = (ULawbyte & 0x80); 
                exponent = (ULawbyte >> 4) & 0x07;
                mantissa = ULawbyte & 0x0F;
                sample = exp_lut_ulaw2linear [exponent] + (mantissa << (exponent + 3));
                if (sign != 0) sample = -sample; 

                newData [i] = (short) (sample & 0xFFFF); 
            } 

            return newData; 
        }

#endif
 
        #endregion
 
        #region Convertors between Linear and ALaw 

        ///  
        /// This routine converts from 16 bit linear to ALaw by direct access to the conversion table.
        /// 
        /// Array of 16 bit linear samples.
        /// Size of the data in the array. 
        /// New buffer of 8 bit ALaw samples.
        static internal byte [] ConvertLinear2ALaw (short [] data, int size) 
        { 
            byte [] newData = new byte [size];
            _aLawCompTableCached = _aLawCompTableCached == null ? CalcLinear2ALawTable () : _aLawCompTableCached; 

            for (int i = 0; i < size; i++)
            {
                unchecked 
                {
                    //newData [i] = ALaw_comp_table [(data [i] / 4) & 0x3fff]; 
                    newData [i] = _aLawCompTableCached [(ushort) data [i] >> 2]; 
                }
            } 
            return newData;
        }

        ///  
        /// This routine converts from ALaw to 16 bit linear by direct access to the conversion table.
        ///  
        /// Array of 8 bit ALaw samples. 
        /// Size of the data in the array.
        /// New buffer of signed 16 bit linear samples 
        static internal short [] ConvertALaw2Linear (byte [] data, int size)
        {

            short [] newData = new short [size]; 
            for (int i = 0; i < size; i++)
            { 
                int sample = ALaw_exp_table [data [i]]; 

                newData [i] = unchecked ((short) sample); 
            }

            return newData;
        } 

        ///  
        /// This routine converts from linear to ALaw. 
        ///
        /// Craig Reese: IDA/Supercomputing Research Center 
        /// Joe Campbell: Department of Defense
        /// 29 September 1989
        ///
        /// References: 
        /// 1) CCITT Recommendation G.711  (very difficult to follow)
        /// 2) "A New Digital Technique for Implementation of Any 
        ///     Continuous PCM Companding Law," Villeret, Michel, 
        ///     et al. 1973 IEEE Int. Conf. on Communications, Vol 1,
        ///     1973, pg. 11.12-11.17 
        /// 3) MIL-STD-188-113,"Interoperability and Performance Standards
        ///     for Analog-to_Digital Conversion Techniques,"
        ///     17 February 1987
        ///  
        /// New buffer of 8 bit ALaw samples
        static private byte [] CalcLinear2ALawTable () 
        { 
            const int ACLIP = 31744;
 
            byte [] table = new byte [((int) UInt16.MaxValue + 1) >> 2];

            for (int i = 0; i < UInt16.MaxValue; i += 4)
            { 
                short data = unchecked ((short) i);
 
                int sample, sign, exponent, mantissa; 
                byte ALawbyte;
 
                unchecked
                {
                    // Extend the sign bit for the sample that is constructed from two bytes
                    sample = (int) ((data >> 2) << 2); 

                    // Get the sample into sign-magnitude. 
                    sign = ((~sample) >> 8) & 0x80;     // set aside the sign 
                    if (sign == 0) sample = -sample;    // get magnitude
                    if (sample > ACLIP) sample = ACLIP; // clip the magnitude 
                }

                // Convert from 16 bit linear to ULaw.
                if (sample >= 256) 
                {
                    exponent = exp_lut_linear2alaw [(sample >> 8) & 0x7F]; 
                    mantissa = (sample >> (exponent + 3)) & 0x0F; 
                    ALawbyte = (byte) ((exponent << 4) | mantissa);
                } 
                else
                {
                    ALawbyte = (byte) (sample >> 4);
                } 

                ALawbyte ^= (byte) (sign ^ 0x55); 
 
                table [i >> 2] = ALawbyte;
            } 

            return table;
        }
 
#if false // kept here for reference
        ///  
        /// This routine converts from ALaw to linear. 
        ///
        /// Craig Reese: IDA/Supercomputing Research Center 
        /// Joe Campbell: Department of Defense
        /// 29 September 1989
        ///
        /// References: 
        /// 1) CCITT Recommendation G.711  (very difficult to follow)
        /// 2) "A New Digital Technique for Implementation of Any 
        ///     Continuous PCM Companding Law," Villeret, Michel, 
        ///     et al. 1973 IEEE Int. Conf. on Communications, Vol 1,
        ///     1973, pg. 11.12-11.17 
        /// 3) MIL-STD-188-113,"Interoperability and Performance Standards
        ///     for Analog-to_Digital Conversion Techniques,"
        ///     17 February 1987
        ///  
        /// Array of 8 bit ALaw samples.
        /// Size of the data in the array. 
        /// New buffer of signed 16 bit linear samples. 
        static internal short [] BuildALawTable (byte [] data, int size)
        { 
            short [] newData = new short [size];
            for (int i = 0; i < size; i++)
            {
                int sign, exponent, mantissa, sample; 
                byte ALawbyte = data [i];
                ALawbyte ^= 0x55; 
                sign = (ALawbyte & 0x80); 
                ALawbyte &= 0x7f;     // get magnitude
                if (ALawbyte >= 16) 
                {
                    exponent = (ALawbyte >> 4) & 0x07;
                    mantissa = ALawbyte & 0x0F;
                    sample = exp_lut_alaw2linear [exponent] + (mantissa << (exponent + 3)); 
                }
                else 
                { 
                    sample = (ALawbyte << 4) + 8;
                } 
                if (sign == 0) sample = -sample;

                newData [i] = unchecked ((short) sample);
            } 

            return newData; 
        } 

#endif 
        #endregion

        #region PCM to PCM
 
        /// 
        /// Empty linear conversion (does nothing, for table consistensy). 
        ///  
        /// Array of audio data in linear format.
        /// Size of the data in the array. 
        /// The same array in linear format.
        static private short [] ConvertLinear2LinearByteShort (byte [] data, int size)
        {
            short [] as1 = new short [size / 2]; 
            unchecked
            { 
                for (int i = 0; i < size; i += 2) 
                {
                    as1 [i / 2] = (short) ((short) data [i] + (short) (data [i + 1] << 8)); 
                }
            }
            return as1;
        } 

        ///  
        /// Empty linear conversion (does nothing, for table consistensy). 
        /// 
        /// Array of audio data in linear format. 
        /// Size of the data in the array.
        /// The same array in linear format.
        static private short [] ConvertLinear8LinearByteShort (byte [] data, int size)
        { 
            short [] as1 = new short [size];
            unchecked 
            { 
                for (int i = 0; i < size; i++)
                { 
                    as1 [i] = (short) (((short) data [i] - 128) << 8);
                }
            }
            return as1; 
        }
 
        ///  
        /// Empty linear conversion (does nothing, for table consistensy).
        ///  
        /// Array of audio data in linear format.
        /// Size of the data in the array.
        /// The same array in linear format.
        static private byte [] ConvertLinear2LinearShortByte (short [] data, int size) 
        {
            byte [] ab = new byte [size * 2]; 
            for (int i = 0; i < size; i++) 
            {
                short s = data [i]; 
                ab [2 * i] = unchecked ((byte) s);
                ab [2 * i + 1] = unchecked ((byte) (s >> 8));
            }
            return ab; // the same format: do nothing 
        }
 
        ///  
        /// Empty linear conversion (does nothing, for table consistensy).
        ///  
        /// Array of audio data in linear format.
        /// Size of the data in the array.
        /// The same array in linear format.
        static private byte [] ConvertLinear8LinearShortByte (short [] data, int size) 
        {
            byte [] ab = new byte [size]; 
            for (int i = 0; i < size; i++) 
            {
                ab [i] = unchecked ((byte) (((ushort) ((data [i] + 127) >> 8)) + 128)); 
            }
            return ab; // the same format: do nothing
        }
 
        #endregion
 
        #endregion 

        //******************************************************************** 
        //
        // Private Members
        //
        //******************************************************************** 

        #region Private Members 
 
        #region Converion tables for direct conversions
 
        // Cached table for aLaw and uLaw convertion (16K * 2 bytes each)
        static private byte [] _uLawCompTableCached;
        static private byte [] _aLawCompTableCached;
 
        #endregion
 
        #region Conversion tables for algorithmic conversions 

        private static readonly int [] exp_lut_linear2alaw = new int [128] 
        {
            1,1,2,2,3,3,3,3,
            4,4,4,4,4,4,4,4,
            5,5,5,5,5,5,5,5, 
            5,5,5,5,5,5,5,5,
            6,6,6,6,6,6,6,6, 
            6,6,6,6,6,6,6,6, 
            6,6,6,6,6,6,6,6,
            6,6,6,6,6,6,6,6, 
            7,7,7,7,7,7,7,7,
            7,7,7,7,7,7,7,7,
            7,7,7,7,7,7,7,7,
            7,7,7,7,7,7,7,7, 
            7,7,7,7,7,7,7,7,
            7,7,7,7,7,7,7,7, 
            7,7,7,7,7,7,7,7 , 
            7 ,7 ,7 ,7 ,7 ,7,7,7
        }; 

        static private int [] exp_lut_linear2ulaw = new int [256]
        {
            0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3, 
            4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
            5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, 
            5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, 
            6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
            6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 
            6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
            6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
            7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
            7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 
            7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
            7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 
            7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 
            7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
            7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 
            7,7,7,7,7,7,7,7 ,7 ,7 ,7 ,7 ,7 ,7,7,7
        };

#if false // keep for reference 
        static private int [] exp_lut_alaw2linear = new int [8] { 0 , 264 , 528 , 1056 , 2112 , 4224 , 8448, 16896 };
        static private int [] exp_lut_ulaw2linear = new int [8] { 0 , 132 , 396 , 924 , 1980 , 4092 , 8316, 16764 }; 
#endif 

        #endregion 

        #region Conversion tables for 'byte' to 'short' converion

        ///  
        /// Table to converts ULaw values to Linear
        ///  
        static private int [] ULaw_exp_table = new int [256] 
        {
            -32124,-31100,-30076,-29052,-28028,-27004,-25980,-24956, 
            -23932,-22908,-21884,-20860,-19836,-18812,-17788,-16764,
            -15996,-15484,-14972,-14460,-13948,-13436,-12924,-12412,
            -11900,-11388,-10876,-10364, -9852, -9340, -8828, -8316,
            -7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140, 
            -5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092,
            -3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004, 
            -2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980, 
            -1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436,
            -1372, -1308, -1244, -1180, -1116, -1052,  -988,  -924, 
            -876,  -844,  -812,  -780,  -748,  -716,  -684,  -652,
            -620,  -588,  -556,  -524,  -492,  -460,  -428,  -396,
            -372,  -356,  -340,  -324,  -308,  -292,  -276,  -260,
            -244,  -228,  -212,  -196,  -180,  -164,  -148,  -132, 
            -120,  -112,  -104,   -96,   -88,   -80,   -72,   -64,
            -56,   -48,   -40,   -32,   -24,   -16,    -8,     0, 
            32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956, 
            23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764,
            15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412, 
            11900, 11388, 10876, 10364,  9852,  9340,  8828,  8316,
            7932,  7676,  7420,  7164,  6908,  6652,  6396,  6140,
            5884,  5628,  5372,  5116,  4860,  4604,  4348,  4092,
            3900,  3772,  3644,  3516,  3388,  3260,  3132,  3004, 
            2876,  2748,  2620,  2492,  2364,  2236,  2108,  1980,
            1884,  1820,  1756,  1692,  1628,  1564,  1500,  1436, 
            1372,  1308,  1244,  1180,  1116,  1052,   988,   924, 
            876,   844,   812,   780,   748,   716,   684,   652,
            620,   588,   556,   524,   492,   460,   428,   396, 
            372,   356,   340,   324,   308,   292,   276,   260,
            244,   228,   212,   196,   180,   164,   148,   132,
            120,   112,   104,    96,    88,    80,    72,    64,
            56,    48,    40,    32,    24,    16,     8,     0 
        };
 
        ///  
        /// Table to converts ALaw values to Linear
        ///  
        static private int [] ALaw_exp_table = new int [256]
        {
            -5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736,
            -7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784, 
            -2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368,
            -3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392, 
            -22016,-20992,-24064,-23040,-17920,-16896,-19968,-18944, 
            -30208,-29184,-32256,-31232,-26112,-25088,-28160,-27136,
            -11008,-10496,-12032,-11520, -8960, -8448, -9984, -9472, 
            -15104,-14592,-16128,-15616,-13056,-12544,-14080,-13568,
            -344,  -328,  -376,  -360,  -280,  -264,  -312,  -296,
            -472,  -456,  -504,  -488,  -408,  -392,  -440,  -424,
            -88,   -72,  -120,  -104,   -24,    -8,   -56,   -40, 
            -216,  -200,  -248,  -232,  -152,  -136,  -184,  -168,
            -1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184, 
            -1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696, 
            -688,  -656,  -752,  -720,  -560,  -528,  -624,  -592,
            -944,  -912, -1008,  -976,  -816,  -784,  -880,  -848, 
            5504,  5248,  6016,  5760,  4480,  4224,  4992,  4736,
            7552,  7296,  8064,  7808,  6528,  6272,  7040,  6784,
            2752,  2624,  3008,  2880,  2240,  2112,  2496,  2368,
            3776,  3648,  4032,  3904,  3264,  3136,  3520,  3392, 
            22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944,
            30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136, 
            11008, 10496, 12032, 11520,  8960,  8448,  9984,  9472, 
            15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568,
            344,   328,   376,   360,   280,   264,   312,   296, 
            472,   456,   504,   488,   408,   392,   440,   424,
            88,    72,   120,   104,    24,     8,    56,    40,
            216,   200,   248,   232,   152,   136,   184,   168,
            1376,  1312,  1504,  1440,  1120,  1056,  1248,  1184, 
            1888,  1824,  2016,  1952,  1632,  1568,  1760,  1696,
            688,   656,   752,   720,   560,   528,   624,   592, 
            944,   912,  1008,   976,   816,   784,   880,   848 
        };
 
#if false // keep for reference

        #region Conversion tables between ALaw and ULaw
        ///  
        /// copy from CCITT G.711 specifications:
        /// u- to ALaw conversions 
        ///  
        static private byte [] s_U2A = new byte [128]
        { 
            1,  1,  2,  2,  3,  3,  4,  4,
            5,  5,  6,  6,  7,  7,  8,  8,
            9,  10, 11, 12, 13, 14, 15, 16,
            17, 18, 19, 20, 21, 22, 23, 24, 
            25, 27, 29, 31, 33, 34, 35, 36,
            37, 38, 39, 40, 41, 42, 43, 44, 
            46, 48, 49, 50, 51, 52, 53, 54, 
            55, 56, 57, 58, 59, 60, 61, 62,
            64, 65, 66, 67, 68, 69, 70, 71, 
            72, 73, 74, 75, 76, 77, 78, 79,
            81, 82, 83, 84, 85, 86, 87, 88,
            89, 90, 91, 92, 93, 94, 95, 96,
            97, 98, 99, 100, 101, 102, 103, 104, 
            105, 106, 107, 108, 109, 110, 111, 112,
            113, 114, 115, 116, 117, 118, 119, 120, 
            121, 122, 123, 124, 125, 126, 127, 128 
        };
 
        /// 
        /// copy from CCITT G.711 specifications:
        /// A- to ULaw conversions
        ///  
        static private byte [] s_A2U = new byte [128]
        { 
            1,  3,  5,  7,  9,  11, 13, 15, 
            16, 17, 18, 19, 20, 21, 22, 23,
            24, 25, 26, 27, 28, 29, 30, 31, 
            32, 32, 33, 33, 34, 34, 35, 35,
            36, 37, 38, 39, 40, 41, 42, 43,
            44, 45, 46, 47, 48, 48, 49, 49,
            50, 51, 52, 53, 54, 55, 56, 57, 
            58, 59, 60, 61, 62, 63, 64, 64,
            65, 66, 67, 68, 69, 70, 71, 72, 
            73, 74, 75, 76, 77, 78, 79, 79, 
            80, 81, 82, 83, 84, 85, 86, 87,
            88, 89, 90, 91, 92, 93, 94, 95, 
            96, 97, 98, 99, 100, 101, 102, 103,
            104, 105, 106, 107, 108, 109, 110, 111,
            112, 113, 114, 115, 116, 117, 118, 119,
            120, 121, 122, 123, 124, 125, 126, 127 
        };
        #endregion 
 
#endif
 
        #endregion

        internal enum WaveFormatTag
        { 
            WAVE_FORMAT_PCM = 1,
            WAVE_FORMAT_ALAW = 0x0006, 
            WAVE_FORMAT_MULAW = 0x0007 
        }
        // delegates 
        delegate short [] ConvertByteShort (byte [] data, int size);
        delegate byte [] ConvertShortByte (short [] data, int size);

        #endregion 
    }
 
    //******************************************************************* 
    //
    // Internal Types 
    //
    //********************************************************************

    #region Internal Types 

    ///  
    /// Supported formats for audio transcoding in SES 
    /// 
    internal enum AudioCodec 
    {
        /// 
        /// Audio format PCM 16 bit
        ///  
        PCM16 = 128,
 
        ///  
        /// Audio format PCM 16 bit
        ///  
        PCM8 = 127,

        /// 
        /// Audio format G.711 mu-law 
        /// 
        G711U = 0, 
 
        /// 
        /// AudioFormat G.711 A-law 
        /// 
        G711A = 8,

        ///  
        /// No audio format specified
        ///  
        Undefined = -1 
    }
 
    #endregion
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
                        

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