61 lines
3.0 KiB
C#
61 lines
3.0 KiB
C#
namespace NAudio.Codecs
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{
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/// <summary>
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/// mu-law decoder
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/// based on code from:
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/// http://hazelware.luggle.com/tutorials/mulawcompression.html
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/// </summary>
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public static class MuLawDecoder
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{
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/// <summary>
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/// only 512 bytes required, so just use a lookup
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/// </summary>
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private static readonly short[] MuLawDecompressTable = new short[256]
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{
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-32124,-31100,-30076,-29052,-28028,-27004,-25980,-24956,
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-23932,-22908,-21884,-20860,-19836,-18812,-17788,-16764,
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-15996,-15484,-14972,-14460,-13948,-13436,-12924,-12412,
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-11900,-11388,-10876,-10364, -9852, -9340, -8828, -8316,
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-7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140,
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-5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092,
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-3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004,
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-2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980,
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-1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436,
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-1372, -1308, -1244, -1180, -1116, -1052, -988, -924,
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-876, -844, -812, -780, -748, -716, -684, -652,
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-620, -588, -556, -524, -492, -460, -428, -396,
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-372, -356, -340, -324, -308, -292, -276, -260,
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-244, -228, -212, -196, -180, -164, -148, -132,
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-120, -112, -104, -96, -88, -80, -72, -64,
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-56, -48, -40, -32, -24, -16, -8, -1,
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32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956,
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23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764,
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15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412,
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11900, 11388, 10876, 10364, 9852, 9340, 8828, 8316,
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7932, 7676, 7420, 7164, 6908, 6652, 6396, 6140,
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5884, 5628, 5372, 5116, 4860, 4604, 4348, 4092,
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3900, 3772, 3644, 3516, 3388, 3260, 3132, 3004,
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2876, 2748, 2620, 2492, 2364, 2236, 2108, 1980,
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1884, 1820, 1756, 1692, 1628, 1564, 1500, 1436,
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1372, 1308, 1244, 1180, 1116, 1052, 988, 924,
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876, 844, 812, 780, 748, 716, 684, 652,
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620, 588, 556, 524, 492, 460, 428, 396,
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372, 356, 340, 324, 308, 292, 276, 260,
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244, 228, 212, 196, 180, 164, 148, 132,
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120, 112, 104, 96, 88, 80, 72, 64,
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56, 48, 40, 32, 24, 16, 8, 0
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};
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/// <summary>
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/// Converts a mu-law encoded byte to a 16 bit linear sample
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/// </summary>
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/// <param name="muLaw">mu-law encoded byte</param>
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/// <returns>Linear sample</returns>
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public static short MuLawToLinearSample(byte muLaw)
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{
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return MuLawDecompressTable[muLaw];
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}
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}
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}
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