126 lines
4.2 KiB
C#
126 lines
4.2 KiB
C#
using System;
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using System.IO;
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// This file is part of the ANX.Framework and originally taken from
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// the AC.AL OpenAL library, released under the MIT License.
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// For details see: http://acal.codeplex.com/license
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namespace WaveUtils
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{
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/// <summary>
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/// http://www.threejacks.com/?q=node/176
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/// </summary>
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internal static class ALaw
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{
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#region Decode Table
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private static readonly short[] DecodeTable =
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{
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-5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736,
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-7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784,
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-2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368,
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-3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392,
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-22016,-20992,-24064,-23040,-17920,-16896,-19968,-18944,
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-30208,-29184,-32256,-31232,-26112,-25088,-28160,-27136,
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-11008,-10496,-12032,-11520,-8960, -8448, -9984, -9472,
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-15104,-14592,-16128,-15616,-13056,-12544,-14080,-13568,
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-344, -328, -376, -360, -280, -264, -312, -296,
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-472, -456, -504, -488, -408, -392, -440, -424,
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-88, -72, -120, -104, -24, -8, -56, -40,
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-216, -200, -248, -232, -152, -136, -184, -168,
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-1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184,
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-1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696,
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-688, -656, -752, -720, -560, -528, -624, -592,
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-944, -912, -1008, -976, -816, -784, -880, -848,
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5504, 5248, 6016, 5760, 4480, 4224, 4992, 4736,
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7552, 7296, 8064, 7808, 6528, 6272, 7040, 6784,
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2752, 2624, 3008, 2880, 2240, 2112, 2496, 2368,
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3776, 3648, 4032, 3904, 3264, 3136, 3520, 3392,
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22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944,
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30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136,
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11008, 10496, 12032, 11520, 8960, 8448, 9984, 9472,
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15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568,
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344, 328, 376, 360, 280, 264, 312, 296,
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472, 456, 504, 488, 408, 392, 440, 424,
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88, 72, 120, 104, 24, 8, 56, 40,
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216, 200, 248, 232, 152, 136, 184, 168,
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1376, 1312, 1504, 1440, 1120, 1056, 1248, 1184,
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1888, 1824, 2016, 1952, 1632, 1568, 1760, 1696,
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688, 656, 752, 720, 560, 528, 624, 592,
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944, 912, 1008, 976, 816, 784, 880, 848
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};
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#endregion
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#region Encode Table
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private static readonly byte[] EncodeTable =
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{
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1, 1, 2, 2, 3, 3, 3, 3,
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4, 4, 4, 4, 4, 4, 4, 4,
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5, 5, 5, 5, 5, 5, 5, 5,
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5, 5, 5, 5, 5, 5, 5, 5,
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6, 6, 6, 6, 6, 6, 6, 6,
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6, 6, 6, 6, 6, 6, 6, 6,
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6, 6, 6, 6, 6, 6, 6, 6,
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6, 6, 6, 6, 6, 6, 6, 6,
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7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7, 7
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};
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#endregion
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#region ConvertToALaw (TODO)
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private static void ConvertToALaw(WaveInfo info)
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{
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//int sign;
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//int exponent;
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//int mantissa;
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//unsigned char compressedByte;
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//sign = ((~sample) >> 8) & 0x80;
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//if (!sign)
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// sample = (short)-sample;
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//if (sample > cClip)
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// sample = cClip;
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//if (sample >= 256)
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//{
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// exponent = (int)ALawCompressTable[(sample >> 8) & 0x7F];
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// mantissa = (sample >> (exponent + 3) ) & 0x0F;
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// compressedByte = ((exponent << 4) | mantissa);
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//}
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//else
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//{
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// compressedByte = (unsigned char)(sample >> 4);
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//}
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//compressedByte ^= (sign ^ 0x55);
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//return compressedByte;
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}
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#endregion
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#region ConvertToPcm
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public static void ConvertToPcm(WaveInfo info, int resultChannelCount)
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{
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using (MemoryStream destStream = new MemoryStream())
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{
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BinaryWriter destWriter = new BinaryWriter(destStream);
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int increment = 1;
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if (info.Channels == 2 && resultChannelCount == 1)
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increment = 2;
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info.Channels = resultChannelCount;
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info.ALFormat = info.Channels == 1 ? ALFormat.Mono16 : ALFormat.Stereo16;
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for (int index = 0; index < info.Data.Length; index += increment)
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destWriter.Write(DecodeTable[info.Data[index]]);
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info.Data = destStream.ToArray();
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}
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}
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#endregion
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}
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}
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