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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
#region Using directives
#endregion
namespace System.Speech.Internal.Synthesis
{
/// <summary>
/// AudioFormatConverter takes its conversion tables from ...\scg\tts\common\vapiio\alaw_ULaw.cpp
/// </summary>
internal static class AudioFormatConverter
{
#region Internal Methods
/// <summary>
/// Finds the converting method based on the specified formats.
/// </summary>
/// <param name="data">Reference to the buffer of audio data.</param>
/// <param name="from">Audio format that the data will be converted from.</param>
/// <param name="to">Audio format that the data will be converted to.</param>
/// <returns>New array with the audio data in requested format.</returns>
internal static 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);
}
/// <summary>
/// Finds the converting method based on the specified formats.
/// </summary>
/// <param name="data">Reference to the buffer of audio data.</param>
/// <param name="from">Audio format that the data will be converted from.</param>
/// <param name="to">Audio format that the data will be converted to.</param>
/// <returns>New array with the audio data in requested format.</returns>
internal static 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);
}
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
#region Private Methods
#region Converters between Linear and ULaw
/// <summary>
/// This routine converts from 16 bit linear to ULaw by direct access to the conversion table.
/// </summary>
/// <param name="data">Array of 16 bit linear samples.</param>
/// <param name="size">Size of the data in the array.</param>
/// <returns>New buffer of 8 bit ULaw samples.</returns>
internal static byte[] ConvertLinear2ULaw(short[] data, int size)
{
byte[] newData = new byte[size];
s_uLawCompTableCached ??= CalcLinear2ULawTable();
for (int i = 0; i < size; i++)
{
unchecked
{
// Extend the sign bit for the sample that is constructed from two bytes
newData[i] = s_uLawCompTableCached[(ushort)data[i] >> 2];
}
}
return newData;
}
/// <summary>
/// This routine converts from ULaw to 16 bit linear by direct access to the conversion table.
/// </summary>
/// <param name="data">Array of 8 bit ULaw samples.</param>
/// <param name="size">Size of the data in the array.</param>
/// <returns>New buffer of signed 16 bit linear samples</returns>
internal static short[] ConvertULaw2Linear(byte[] data, int size)
{
short[] newData = new short[size];
for (int i = 0; i < size; i++)
{
int sample = s_ULaw_exp_table[data[i]];
newData[i] = unchecked((short)sample);
}
return newData;
}
/// <summary>
/// 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
/// </summary>
/// <returns>New buffer of 8 bit ULaw samples</returns>
private static 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[(ushort.MaxValue + 1) >> 2];
for (int i = 0; i < ushort.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 = (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 += uBIAS;
exponent = s_exp_lut_linear2ulaw[(sample >> 7) & 0xFF];
mantissa = (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;
}
#endregion
#region Converters between Linear and ALaw
/// <summary>
/// This routine converts from 16 bit linear to ALaw by direct access to the conversion table.
/// </summary>
/// <param name="data">Array of 16 bit linear samples.</param>
/// <param name="size">Size of the data in the array.</param>
/// <returns>New buffer of 8 bit ALaw samples.</returns>
internal static byte[] ConvertLinear2ALaw(short[] data, int size)
{
byte[] newData = new byte[size];
s_aLawCompTableCached ??= CalcLinear2ALawTable();
for (int i = 0; i < size; i++)
{
unchecked
{
//newData [i] = ALaw_comp_table [(data [i] / 4) & 0x3fff];
newData[i] = s_aLawCompTableCached[(ushort)data[i] >> 2];
}
}
return newData;
}
/// <summary>
/// This routine converts from ALaw to 16 bit linear by direct access to the conversion table.
/// </summary>
/// <param name="data">Array of 8 bit ALaw samples.</param>
/// <param name="size">Size of the data in the array.</param>
/// <returns>New buffer of signed 16 bit linear samples</returns>
internal static short[] ConvertALaw2Linear(byte[] data, int size)
{
short[] newData = new short[size];
for (int i = 0; i < size; i++)
{
int sample = s_ALaw_exp_table[data[i]];
newData[i] = unchecked((short)sample);
}
return newData;
}
/// <summary>
/// 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
/// </summary>
/// <returns>New buffer of 8 bit ALaw samples</returns>
private static byte[] CalcLinear2ALawTable()
{
const int ACLIP = 31744;
byte[] table = new byte[(ushort.MaxValue + 1) >> 2];
for (int i = 0; i < ushort.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 = (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 = s_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;
}
#endregion
#region PCM to PCM
/// <summary>
/// Empty linear conversion (does nothing, for table consistency).
/// </summary>
/// <param name="data">Array of audio data in linear format.</param>
/// <param name="size">Size of the data in the array.</param>
/// <returns>The same array in linear format.</returns>
private static 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)(data[i] + (short)(data[i + 1] << 8));
}
}
return as1;
}
/// <summary>
/// Empty linear conversion (does nothing, for table consistency).
/// </summary>
/// <param name="data">Array of audio data in linear format.</param>
/// <param name="size">Size of the data in the array.</param>
/// <returns>The same array in linear format.</returns>
private static short[] ConvertLinear8LinearByteShort(byte[] data, int size)
{
short[] as1 = new short[size];
unchecked
{
for (int i = 0; i < size; i++)
{
as1[i] = (short)((data[i] - 128) << 8);
}
}
return as1;
}
/// <summary>
/// Empty linear conversion (does nothing, for table consistency).
/// </summary>
/// <param name="data">Array of audio data in linear format.</param>
/// <param name="size">Size of the data in the array.</param>
/// <returns>The same array in linear format.</returns>
private static 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
}
/// <summary>
/// Empty linear conversion (does nothing, for table consistency).
/// </summary>
/// <param name="data">Array of audio data in linear format.</param>
/// <param name="size">Size of the data in the array.</param>
/// <returns>The same array in linear format.</returns>
private static 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
#region Private Members
#region Conversion tables for direct conversions
// Cached table for aLaw and uLaw conversion (16K * 2 bytes each)
private static byte[]? s_uLawCompTableCached;
private static byte[]? s_aLawCompTableCached;
#endregion
#region Conversion tables for algorithmic conversions
private static readonly int[] s_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
};
private static int[] s_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
};
#endregion
#region Conversion tables for 'byte' to 'short' conversion
/// <summary>
/// Table to converts ULaw values to Linear
/// </summary>
private static int[] s_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
};
/// <summary>
/// Table to converts ALaw values to Linear
/// </summary>
private static int[] s_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
};
#endregion
internal enum WaveFormatTag
{
WAVE_FORMAT_PCM = 1,
WAVE_FORMAT_ALAW = 0x0006,
WAVE_FORMAT_MULAW = 0x0007
}
// delegates
private delegate short[] ConvertByteShort(byte[] data, int size);
private delegate byte[] ConvertShortByte(short[] data, int size);
#endregion
}
#region Internal Types
/// <summary>
/// Supported formats for audio transcoding in SES
/// </summary>
internal enum AudioCodec
{
/// <summary>
/// Audio format PCM 16 bit
/// </summary>
PCM16 = 128,
/// <summary>
/// Audio format PCM 16 bit
/// </summary>
PCM8 = 127,
/// <summary>
/// Audio format G.711 mu-law
/// </summary>
G711U = 0,
/// <summary>
/// AudioFormat G.711 A-law
/// </summary>
G711A = 8,
/// <summary>
/// No audio format specified
/// </summary>
Undefined = -1
}
#endregion
}
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