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369 lines
9.7 KiB
369 lines
9.7 KiB
/**
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* Digital Voice Modem - Host Software
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* GPLv2 Open Source. Use is subject to license terms.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* @package DVM / Host Software
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*
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*/
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//
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// Based on code from the MMDVMHost project. (https://github.com/g4klx/MMDVMHost)
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// Licensed under the GPLv2 License (https://opensource.org/licenses/GPL-2.0)
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//
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/*
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* Copyright (C) 2016 by Jonathan Naylor G4KLX
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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 2 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
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "Defines.h"
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#include "p25/Audio.h"
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#include "p25/P25Utils.h"
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#include "edac/Golay24128.h"
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#include "edac/Hamming.h"
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using namespace p25;
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#include <cstdio>
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#include <cassert>
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// ---------------------------------------------------------------------------
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// Public Class Members
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// ---------------------------------------------------------------------------
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/// <summary>
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/// Initializes a new instance of the Audio class.
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/// </summary>
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Audio::Audio() :
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m_fec()
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{
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/* stub */
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}
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/// <summary>
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/// Finalizes a instance of the Audio class.
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/// </summary>
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Audio::~Audio()
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{
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/* stub */
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}
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/// <summary>
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/// Process P25 IMBE audio data.
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/// </summary>
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/// <param name="data"></param>
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/// <returns>Number of errors corrected.</returns>
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uint32_t Audio::process(uint8_t* data)
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{
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assert(data != NULL);
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uint32_t errs = 0U;
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uint8_t imbe[18U];
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P25Utils::decode(data, imbe, 114U, 262U);
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errs += m_fec.regenerateIMBE(imbe);
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P25Utils::encode(imbe, data, 114U, 262U);
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P25Utils::decode(data, imbe, 262U, 410U);
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errs += m_fec.regenerateIMBE(imbe);
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P25Utils::encode(imbe, data, 262U, 410U);
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P25Utils::decode(data, imbe, 452U, 600U);
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errs += m_fec.regenerateIMBE(imbe);
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P25Utils::encode(imbe, data, 452U, 600U);
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P25Utils::decode(data, imbe, 640U, 788U);
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errs += m_fec.regenerateIMBE(imbe);
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P25Utils::encode(imbe, data, 640U, 788U);
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P25Utils::decode(data, imbe, 830U, 978U);
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errs += m_fec.regenerateIMBE(imbe);
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P25Utils::encode(imbe, data, 830U, 978U);
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P25Utils::decode(data, imbe, 1020U, 1168U);
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errs += m_fec.regenerateIMBE(imbe);
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P25Utils::encode(imbe, data, 1020U, 1168U);
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P25Utils::decode(data, imbe, 1208U, 1356U);
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errs += m_fec.regenerateIMBE(imbe);
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P25Utils::encode(imbe, data, 1208U, 1356U);
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P25Utils::decode(data, imbe, 1398U, 1546U);
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errs += m_fec.regenerateIMBE(imbe);
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P25Utils::encode(imbe, data, 1398U, 1546U);
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P25Utils::decode(data, imbe, 1578U, 1726U);
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errs += m_fec.regenerateIMBE(imbe);
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P25Utils::encode(imbe, data, 1578U, 1726U);
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return errs;
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}
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/// <summary>
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/// Decode a P25 IMBE audio frame.
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/// </summary>
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/// <param name="data"></param>
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/// <param name="imbe"></param>
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/// <param name="n"></param>
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void Audio::decode(const uint8_t* data, uint8_t* imbe, uint32_t n)
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{
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assert(data != NULL);
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assert(imbe != NULL);
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uint8_t temp[18U];
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switch (n) {
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case 0U:
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P25Utils::decode(data, temp, 114U, 262U);
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break;
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case 1U:
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P25Utils::decode(data, temp, 262U, 410U);
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break;
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case 2U:
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P25Utils::decode(data, temp, 452U, 600U);
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break;
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case 3U:
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P25Utils::decode(data, temp, 640U, 788U);
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break;
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case 4U:
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P25Utils::decode(data, temp, 830U, 978U);
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break;
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case 5U:
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P25Utils::decode(data, temp, 1020U, 1168U);
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break;
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case 6U:
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P25Utils::decode(data, temp, 1208U, 1356U);
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break;
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case 7U:
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P25Utils::decode(data, temp, 1398U, 1546U);
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break;
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case 8U:
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P25Utils::decode(data, temp, 1578U, 1726U);
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break;
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default:
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return;
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}
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bool bit[144U];
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// De-interleave
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for (uint32_t i = 0U; i < 144U; i++) {
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uint32_t n = edac::IMBE_INTERLEAVE[i];
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bit[i] = READ_BIT(temp, n);
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}
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// now ..
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// 12 voice bits 0
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// 11 golay bits 12
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//
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// 12 voice bits 23
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// 11 golay bits 35
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//
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// 12 voice bits 46
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// 11 golay bits 58
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//
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// 12 voice bits 69
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// 11 golay bits 81
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//
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// 11 voice bits 92
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// 4 hamming bits 103
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//
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// 11 voice bits 107
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// 4 hamming bits 118
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//
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// 11 voice bits 122
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// 4 hamming bits 133
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//
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// 7 voice bits 137
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// c0
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uint32_t c0data = 0U;
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for (uint32_t i = 0U; i < 12U; i++)
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c0data = (c0data << 1) | (bit[i] ? 0x01U : 0x00U);
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bool prn[114U];
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// Create the whitening vector and save it for future use
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uint32_t p = 16U * c0data;
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for (uint32_t i = 0U; i < 114U; i++) {
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p = (173U * p + 13849U) % 65536U;
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prn[i] = p >= 32768U;
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}
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// De-whiten some bits
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for (uint32_t i = 0U; i < 114U; i++)
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bit[i + 23U] ^= prn[i];
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uint32_t offset = 0U;
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for (uint32_t i = 0U; i < 12U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 0U]);
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for (uint32_t i = 0U; i < 12U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 23U]);
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for (uint32_t i = 0U; i < 12U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 46U]);
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for (uint32_t i = 0U; i < 12U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 69U]);
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for (uint32_t i = 0U; i < 11U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 92U]);
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for (uint32_t i = 0U; i < 11U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 107U]);
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for (uint32_t i = 0U; i < 11U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 122U]);
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for (uint32_t i = 0U; i < 7U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 137U]);
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}
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/// <summary>
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/// Encode a P25 IMBE audio frame.
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/// </summary>
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/// <param name="data"></param>
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/// <param name="imbe"></param>
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/// <param name="n"></param>
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void Audio::encode(uint8_t* data, const uint8_t* imbe, uint32_t n)
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{
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assert(data != NULL);
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assert(imbe != NULL);
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bool bTemp[144U];
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bool* bit = bTemp;
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// c0
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uint32_t c0 = 0U;
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for (uint32_t i = 0U; i < 12U; i++) {
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bool b = READ_BIT(imbe, i);
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c0 = (c0 << 1) | (b ? 0x01U : 0x00U);
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}
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uint32_t g2 = edac::Golay24128::encode23127(c0);
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for (int i = 23; i >= 0; i--) {
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bit[i] = (g2 & 0x01U) == 0x01U;
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g2 >>= 1;
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}
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bit += 23U;
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// c1
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uint32_t c1 = 0U;
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for (uint32_t i = 12U; i < 24U; i++) {
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bool b = READ_BIT(imbe, i);
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c1 = (c1 << 1) | (b ? 0x01U : 0x00U);
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}
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g2 = edac::Golay24128::encode23127(c1);
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for (int i = 23; i >= 0; i--) {
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bit[i] = (g2 & 0x01U) == 0x01U;
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g2 >>= 1;
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}
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bit += 23U;
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// c2
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uint32_t c2 = 0;
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for (uint32_t i = 24U; i < 36U; i++) {
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bool b = READ_BIT(imbe, i);
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c2 = (c2 << 1) | (b ? 0x01U : 0x00U);
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}
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g2 = edac::Golay24128::encode23127(c2);
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for (int i = 23; i >= 0; i--) {
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bit[i] = (g2 & 0x01U) == 0x01U;
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g2 >>= 1;
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}
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bit += 23U;
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// c3
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uint32_t c3 = 0U;
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for (uint32_t i = 36U; i < 48U; i++) {
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bool b = READ_BIT(imbe, i);
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c3 = (c3 << 1) | (b ? 0x01U : 0x00U);
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}
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g2 = edac::Golay24128::encode23127(c3);
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for (int i = 23; i >= 0; i--) {
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bit[i] = (g2 & 0x01U) == 0x01U;
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g2 >>= 1;
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}
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bit += 23U;
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// c4
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for (uint32_t i = 0U; i < 11U; i++)
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bit[i] = READ_BIT(imbe, i + 48U);
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edac::Hamming::encode15113_1(bit);
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bit += 15U;
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// c5
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for (uint32_t i = 0U; i < 11U; i++)
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bit[i] = READ_BIT(imbe, i + 59U);
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edac::Hamming::encode15113_1(bit);
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bit += 15U;
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// c6
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for (uint32_t i = 0U; i < 11U; i++)
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bit[i] = READ_BIT(imbe, i + 70U);
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edac::Hamming::encode15113_1(bit);
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bit += 15U;
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// c7
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for (uint32_t i = 0U; i < 7U; i++)
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bit[i] = READ_BIT(imbe, i + 81U);
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bool prn[114U];
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// Create the whitening vector and save it for future use
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uint32_t p = 16U * c0;
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for (uint32_t i = 0U; i < 114U; i++) {
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p = (173U * p + 13849U) % 65536U;
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prn[i] = p >= 32768U;
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}
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// Whiten some bits
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for (uint32_t i = 0U; i < 114U; i++)
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bTemp[i + 23U] ^= prn[i];
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uint8_t temp[18U];
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// Interleave
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for (uint32_t i = 0U; i < 144U; i++) {
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uint32_t n = edac::IMBE_INTERLEAVE[i];
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WRITE_BIT(temp, n, bTemp[i]);
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}
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switch (n) {
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case 0U:
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P25Utils::encode(temp, data, 114U, 262U);
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break;
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case 1U:
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P25Utils::encode(temp, data, 262U, 410U);
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break;
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case 2U:
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P25Utils::encode(temp, data, 452U, 600U);
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break;
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case 3U:
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P25Utils::encode(temp, data, 640U, 788U);
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break;
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case 4U:
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P25Utils::encode(temp, data, 830U, 978U);
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break;
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case 5U:
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P25Utils::encode(temp, data, 1020U, 1168U);
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break;
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case 6U:
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P25Utils::encode(temp, data, 1208U, 1356U);
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break;
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case 7U:
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P25Utils::encode(temp, data, 1398U, 1546U);
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break;
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case 8U:
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P25Utils::encode(temp, data, 1578U, 1726U);
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break;
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default:
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return;
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}
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}
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