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/*
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* Copyright (C) 2024 by Andreas Theofilu <andreas@theosys.at>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "taudioconvert.h"
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#include "terror.h"
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TAudioConvert::TAudioConvert()
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{
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DECL_TRACER("TAudioConvert::TAudioConvert()");
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}
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TAudioConvert::~TAudioConvert()
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{
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DECL_TRACER("TAudioConvert::~TAudioConvert()");
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}
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int16_t TAudioConvert::uLawDecodeDigital(int8_t number)
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{
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const uint16_t MULAW_BIAS = 33;
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uint8_t sign = 0, position = 0;
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int16_t decoded = 0;
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number = ~number;
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if (number & 0x80)
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{
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number &= ~(1 << 7);
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sign = -1;
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}
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position = ((number & 0xF0) >> 4) + 5;
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decoded = ((1 << position) | ((number & 0x0F) << (position - 4)) | (1 << (position - 5))) - MULAW_BIAS;
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return (sign == 0) ? (decoded) : (-(decoded));
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}
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int8_t TAudioConvert::uLawEncodeDigital(int16_t number)
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{
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const uint16_t MULAW_MAX = 0x1FFF;
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const uint16_t MULAW_BIAS = 33;
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uint16_t mask = 0x1000;
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uint8_t sign = 0;
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uint8_t position = 12;
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uint8_t lsb = 0;
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if (number < 0)
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{
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number = -number;
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sign = 0x80;
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}
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number += MULAW_BIAS;
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if (number > MULAW_MAX)
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number = MULAW_MAX;
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for (; ((number & mask) != mask && position >= 5); mask >>= 1, position--)
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;
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lsb = (number >> (position - 4)) & 0x0f;
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return (~(sign | ((position - 5) << 4) | lsb));
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}
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int8_t TAudioConvert::linearToMuLaw(int16_t sample)
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{
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//We get the sign
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int sign = (sample >> 8) & 0x0080;
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if (sign != 0)
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sample = -sample;
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if (sample > cClip)
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sample = cClip;
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sample += cBias;
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int exponent = static_cast<int>(MuLawCompressTable[(sample >> 7) & 0xFF]);
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int mantissa = (sample >> (exponent + 3)) & 0x0F;
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int compressedByte = ~(sign | (exponent << 4) | mantissa);
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return static_cast<int8_t>(compressedByte);
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}
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int8_t TAudioConvert::linearToALaw(int16_t sample)
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{
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int16_t sign, exponent, mantissa;
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uint8_t 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 = static_cast<int16_t>(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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compressedByte = static_cast<uint8_t>(sample >> 4);
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compressedByte ^= (sign ^ 0x55);
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return compressedByte;
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}
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int16_t TAudioConvert::muLawToLinear(uint8_t ulawbyte)
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{
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return MuLawDecompressTable[ulawbyte];
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}
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int16_t TAudioConvert::aLawToLinear(uint8_t alawbyte)
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{
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return ALawDecompressTable[alawbyte];
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}
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