1 | /* The copyright in this software is being made available under the BSD |
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2 | * License, included below. This software may be subject to other third party |
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3 | * and contributor rights, including patent rights, and no such rights are |
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4 | * granted under this license. |
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5 | * |
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6 | * Copyright (c) 2010-2015, ITU/ISO/IEC |
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7 | * All rights reserved. |
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8 | * |
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9 | * Redistribution and use in source and binary forms, with or without |
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10 | * modification, are permitted provided that the following conditions are met: |
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11 | * |
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12 | * * Redistributions of source code must retain the above copyright notice, |
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13 | * this list of conditions and the following disclaimer. |
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14 | * * Redistributions in binary form must reproduce the above copyright notice, |
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15 | * this list of conditions and the following disclaimer in the documentation |
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16 | * and/or other materials provided with the distribution. |
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17 | * * Neither the name of the ITU/ISO/IEC nor the names of its contributors may |
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18 | * be used to endorse or promote products derived from this software without |
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19 | * specific prior written permission. |
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20 | * |
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21 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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22 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS |
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25 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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26 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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27 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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28 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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29 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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30 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF |
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31 | * THE POSSIBILITY OF SUCH DAMAGE. |
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32 | */ |
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33 | |
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34 | /** \file TComBitStream.cpp |
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35 | \brief class for handling bitstream |
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36 | */ |
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37 | |
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38 | #include <stdint.h> |
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39 | #include <vector> |
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40 | #include "TComBitStream.h" |
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41 | #include <string.h> |
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42 | #include <memory.h> |
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43 | |
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44 | using namespace std; |
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45 | |
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46 | //! \ingroup TLibCommon |
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47 | //! \{ |
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48 | |
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49 | // ==================================================================================================================== |
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50 | // Constructor / destructor / create / destroy |
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51 | // ==================================================================================================================== |
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52 | |
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53 | TComOutputBitstream::TComOutputBitstream() |
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54 | { |
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55 | clear(); |
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56 | } |
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57 | |
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58 | TComOutputBitstream::~TComOutputBitstream() |
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59 | { |
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60 | } |
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61 | |
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62 | |
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63 | TComInputBitstream::TComInputBitstream() |
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64 | : m_fifo() |
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65 | , m_emulationPreventionByteLocation() |
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66 | , m_fifo_idx(0) |
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67 | , m_num_held_bits(0) |
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68 | , m_held_bits(0) |
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69 | , m_numBitsRead(0) |
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70 | { } |
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71 | |
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72 | TComInputBitstream::TComInputBitstream(const TComInputBitstream &src) |
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73 | : m_fifo(src.m_fifo) |
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74 | , m_emulationPreventionByteLocation(src.m_emulationPreventionByteLocation) |
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75 | , m_fifo_idx(src.m_fifo_idx) |
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76 | , m_num_held_bits(src.m_num_held_bits) |
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77 | , m_held_bits(src.m_held_bits) |
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78 | , m_numBitsRead(src.m_numBitsRead) |
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79 | { } |
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80 | |
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81 | // ==================================================================================================================== |
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82 | // Public member functions |
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83 | // ==================================================================================================================== |
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84 | |
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85 | Void TComInputBitstream::resetToStart() |
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86 | { |
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87 | m_fifo_idx=0; |
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88 | m_num_held_bits=0; |
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89 | m_held_bits=0; |
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90 | m_numBitsRead=0; |
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91 | } |
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92 | |
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93 | Char* TComOutputBitstream::getByteStream() const |
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94 | { |
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95 | return (Char*) &m_fifo.front(); |
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96 | } |
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97 | |
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98 | UInt TComOutputBitstream::getByteStreamLength() |
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99 | { |
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100 | return UInt(m_fifo.size()); |
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101 | } |
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102 | |
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103 | Void TComOutputBitstream::clear() |
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104 | { |
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105 | m_fifo.clear(); |
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106 | m_held_bits = 0; |
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107 | m_num_held_bits = 0; |
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108 | } |
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109 | |
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110 | Void TComOutputBitstream::write ( UInt uiBits, UInt uiNumberOfBits ) |
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111 | { |
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112 | assert( uiNumberOfBits <= 32 ); |
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113 | assert( uiNumberOfBits == 32 || (uiBits & (~0 << uiNumberOfBits)) == 0 ); |
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114 | |
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115 | /* any modulo 8 remainder of num_total_bits cannot be written this time, |
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116 | * and will be held until next time. */ |
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117 | UInt num_total_bits = uiNumberOfBits + m_num_held_bits; |
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118 | UInt next_num_held_bits = num_total_bits % 8; |
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119 | |
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120 | /* form a byte aligned word (write_bits), by concatenating any held bits |
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121 | * with the new bits, discarding the bits that will form the next_held_bits. |
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122 | * eg: H = held bits, V = n new bits /---- next_held_bits |
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123 | * len(H)=7, len(V)=1: ... ---- HHHH HHHV . 0000 0000, next_num_held_bits=0 |
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124 | * len(H)=7, len(V)=2: ... ---- HHHH HHHV . V000 0000, next_num_held_bits=1 |
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125 | * if total_bits < 8, the value of v_ is not used */ |
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126 | UChar next_held_bits = uiBits << (8 - next_num_held_bits); |
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127 | |
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128 | if (!(num_total_bits >> 3)) |
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129 | { |
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130 | /* insufficient bits accumulated to write out, append new_held_bits to |
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131 | * current held_bits */ |
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132 | /* NB, this requires that v only contains 0 in bit positions {31..n} */ |
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133 | m_held_bits |= next_held_bits; |
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134 | m_num_held_bits = next_num_held_bits; |
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135 | return; |
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136 | } |
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137 | |
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138 | /* topword serves to justify held_bits to align with the msb of uiBits */ |
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139 | UInt topword = (uiNumberOfBits - next_num_held_bits) & ~((1 << 3) -1); |
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140 | UInt write_bits = (m_held_bits << topword) | (uiBits >> next_num_held_bits); |
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141 | |
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142 | switch (num_total_bits >> 3) |
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143 | { |
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144 | case 4: m_fifo.push_back(write_bits >> 24); |
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145 | case 3: m_fifo.push_back(write_bits >> 16); |
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146 | case 2: m_fifo.push_back(write_bits >> 8); |
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147 | case 1: m_fifo.push_back(write_bits); |
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148 | } |
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149 | |
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150 | m_held_bits = next_held_bits; |
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151 | m_num_held_bits = next_num_held_bits; |
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152 | } |
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153 | |
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154 | Void TComOutputBitstream::writeAlignOne() |
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155 | { |
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156 | UInt num_bits = getNumBitsUntilByteAligned(); |
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157 | write((1 << num_bits) - 1, num_bits); |
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158 | return; |
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159 | } |
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160 | |
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161 | Void TComOutputBitstream::writeAlignZero() |
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162 | { |
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163 | if (0 == m_num_held_bits) |
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164 | { |
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165 | return; |
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166 | } |
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167 | m_fifo.push_back(m_held_bits); |
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168 | m_held_bits = 0; |
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169 | m_num_held_bits = 0; |
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170 | } |
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171 | |
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172 | /** |
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173 | - add substream to the end of the current bitstream |
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174 | . |
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175 | \param pcSubstream substream to be added |
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176 | */ |
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177 | Void TComOutputBitstream::addSubstream( TComOutputBitstream* pcSubstream ) |
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178 | { |
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179 | UInt uiNumBits = pcSubstream->getNumberOfWrittenBits(); |
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180 | |
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181 | const vector<uint8_t>& rbsp = pcSubstream->getFIFO(); |
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182 | for (vector<uint8_t>::const_iterator it = rbsp.begin(); it != rbsp.end();) |
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183 | { |
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184 | write(*it++, 8); |
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185 | } |
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186 | if (uiNumBits&0x7) |
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187 | { |
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188 | write(pcSubstream->getHeldBits()>>(8-(uiNumBits&0x7)), uiNumBits&0x7); |
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189 | } |
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190 | } |
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191 | |
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192 | Void TComOutputBitstream::writeByteAlignment() |
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193 | { |
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194 | write( 1, 1); |
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195 | writeAlignZero(); |
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196 | } |
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197 | |
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198 | Int TComOutputBitstream::countStartCodeEmulations() |
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199 | { |
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200 | UInt cnt = 0; |
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201 | vector<uint8_t>& rbsp = getFIFO(); |
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202 | for (vector<uint8_t>::iterator it = rbsp.begin(); it != rbsp.end();) |
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203 | { |
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204 | vector<uint8_t>::iterator found = it; |
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205 | do |
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206 | { |
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207 | // find the next emulated 00 00 {00,01,02,03} |
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208 | // NB, end()-1, prevents finding a trailing two byte sequence |
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209 | found = search_n(found, rbsp.end()-1, 2, 0); |
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210 | found++; |
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211 | // if not found, found == end, otherwise found = second zero byte |
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212 | if (found == rbsp.end()) |
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213 | { |
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214 | break; |
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215 | } |
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216 | if (*(++found) <= 3) |
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217 | { |
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218 | break; |
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219 | } |
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220 | } while (true); |
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221 | it = found; |
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222 | if (found != rbsp.end()) |
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223 | { |
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224 | cnt++; |
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225 | } |
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226 | } |
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227 | return cnt; |
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228 | } |
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229 | |
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230 | /** |
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231 | * read uiNumberOfBits from bitstream without updating the bitstream |
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232 | * state, storing the result in ruiBits. |
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233 | * |
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234 | * If reading uiNumberOfBits would overrun the bitstream buffer, |
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235 | * the bitstream is effectively padded with sufficient zero-bits to |
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236 | * avoid the overrun. |
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237 | */ |
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238 | Void TComInputBitstream::pseudoRead ( UInt uiNumberOfBits, UInt& ruiBits ) |
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239 | { |
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240 | UInt saved_num_held_bits = m_num_held_bits; |
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241 | UChar saved_held_bits = m_held_bits; |
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242 | UInt saved_fifo_idx = m_fifo_idx; |
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243 | #if P0138_USE_ALT_CPB_PARAMS_FLAG |
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244 | UInt saved_numBitsRead = m_numBitsRead; |
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245 | #endif |
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246 | |
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247 | UInt num_bits_to_read = min(uiNumberOfBits, getNumBitsLeft()); |
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248 | read(num_bits_to_read, ruiBits); |
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249 | ruiBits <<= (uiNumberOfBits - num_bits_to_read); |
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250 | |
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251 | m_fifo_idx = saved_fifo_idx; |
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252 | m_held_bits = saved_held_bits; |
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253 | m_num_held_bits = saved_num_held_bits; |
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254 | #if P0138_USE_ALT_CPB_PARAMS_FLAG |
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255 | m_numBitsRead = saved_numBitsRead; |
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256 | #endif |
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257 | } |
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258 | |
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259 | |
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260 | Void TComInputBitstream::read (UInt uiNumberOfBits, UInt& ruiBits) |
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261 | { |
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262 | assert( uiNumberOfBits <= 32 ); |
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263 | |
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264 | m_numBitsRead += uiNumberOfBits; |
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265 | |
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266 | /* NB, bits are extracted from the MSB of each byte. */ |
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267 | UInt retval = 0; |
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268 | if (uiNumberOfBits <= m_num_held_bits) |
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269 | { |
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270 | /* n=1, len(H)=7: -VHH HHHH, shift_down=6, mask=0xfe |
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271 | * n=3, len(H)=7: -VVV HHHH, shift_down=4, mask=0xf8 |
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272 | */ |
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273 | retval = m_held_bits >> (m_num_held_bits - uiNumberOfBits); |
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274 | retval &= ~(0xff << uiNumberOfBits); |
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275 | m_num_held_bits -= uiNumberOfBits; |
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276 | ruiBits = retval; |
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277 | return; |
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278 | } |
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279 | |
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280 | /* all num_held_bits will go into retval |
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281 | * => need to mask leftover bits from previous extractions |
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282 | * => align retval with top of extracted word */ |
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283 | /* n=5, len(H)=3: ---- -VVV, mask=0x07, shift_up=5-3=2, |
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284 | * n=9, len(H)=3: ---- -VVV, mask=0x07, shift_up=9-3=6 */ |
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285 | uiNumberOfBits -= m_num_held_bits; |
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286 | retval = m_held_bits & ~(0xff << m_num_held_bits); |
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287 | retval <<= uiNumberOfBits; |
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288 | |
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289 | /* number of whole bytes that need to be loaded to form retval */ |
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290 | /* n=32, len(H)=0, load 4bytes, shift_down=0 |
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291 | * n=32, len(H)=1, load 4bytes, shift_down=1 |
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292 | * n=31, len(H)=1, load 4bytes, shift_down=1+1 |
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293 | * n=8, len(H)=0, load 1byte, shift_down=0 |
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294 | * n=8, len(H)=3, load 1byte, shift_down=3 |
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295 | * n=5, len(H)=1, load 1byte, shift_down=1+3 |
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296 | */ |
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297 | UInt aligned_word = 0; |
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298 | UInt num_bytes_to_load = (uiNumberOfBits - 1) >> 3; |
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299 | assert(m_fifo_idx + num_bytes_to_load < m_fifo.size()); |
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300 | |
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301 | switch (num_bytes_to_load) |
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302 | { |
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303 | case 3: aligned_word = m_fifo[m_fifo_idx++] << 24; |
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304 | case 2: aligned_word |= m_fifo[m_fifo_idx++] << 16; |
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305 | case 1: aligned_word |= m_fifo[m_fifo_idx++] << 8; |
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306 | case 0: aligned_word |= m_fifo[m_fifo_idx++]; |
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307 | } |
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308 | |
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309 | /* resolve remainder bits */ |
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310 | UInt next_num_held_bits = (32 - uiNumberOfBits) % 8; |
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311 | |
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312 | /* copy required part of aligned_word into retval */ |
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313 | retval |= aligned_word >> next_num_held_bits; |
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314 | |
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315 | /* store held bits */ |
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316 | m_num_held_bits = next_num_held_bits; |
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317 | m_held_bits = aligned_word; |
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318 | |
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319 | ruiBits = retval; |
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320 | } |
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321 | |
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322 | /** |
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323 | * insert the contents of the bytealigned (and flushed) bitstream src |
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324 | * into this at byte position pos. |
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325 | */ |
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326 | Void TComOutputBitstream::insertAt(const TComOutputBitstream& src, UInt pos) |
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327 | { |
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328 | UInt src_bits = src.getNumberOfWrittenBits(); |
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329 | assert(0 == src_bits % 8); |
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330 | |
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331 | vector<uint8_t>::iterator at = m_fifo.begin() + pos; |
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332 | m_fifo.insert(at, src.m_fifo.begin(), src.m_fifo.end()); |
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333 | } |
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334 | |
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335 | UInt TComInputBitstream::readOutTrailingBits () |
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336 | { |
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337 | UInt count=0; |
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338 | UInt uiBits = 0; |
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339 | |
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340 | while ( ( getNumBitsLeft() > 0 ) && (getNumBitsUntilByteAligned()!=0) ) |
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341 | { |
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342 | count++; |
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343 | read ( 1, uiBits ); |
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344 | } |
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345 | return count; |
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346 | } |
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347 | // |
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348 | //TComOutputBitstream& TComOutputBitstream::operator= (const TComOutputBitstream& src) |
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349 | //{ |
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350 | // vector<uint8_t>::iterator at = m_fifo.begin(); |
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351 | // m_fifo.insert(at, src.m_fifo.begin(), src.m_fifo.end()); |
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352 | // |
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353 | // m_num_held_bits = src.m_num_held_bits; |
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354 | // m_held_bits = src.m_held_bits; |
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355 | // |
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356 | // return *this; |
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357 | //} |
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358 | |
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359 | /** |
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360 | Extract substream from the current bitstream. |
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361 | |
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362 | \param uiNumBits number of bits to transfer |
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363 | */ |
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364 | TComInputBitstream *TComInputBitstream::extractSubstream( UInt uiNumBits ) |
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365 | { |
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366 | UInt uiNumBytes = uiNumBits/8; |
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367 | TComInputBitstream *pResult = new TComInputBitstream; |
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368 | |
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369 | std::vector<uint8_t> &buf = pResult->getFifo(); |
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370 | buf.reserve((uiNumBits+7)>>3); |
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371 | |
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372 | if (m_num_held_bits == 0) |
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373 | { |
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374 | std::size_t currentOutputBufferSize=buf.size(); |
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375 | const UInt uiNumBytesToReadFromFifo = std::min<UInt>(uiNumBytes, m_fifo.size() - m_fifo_idx); |
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376 | buf.resize(currentOutputBufferSize+uiNumBytes); |
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377 | memcpy(&(buf[currentOutputBufferSize]), &(m_fifo[m_fifo_idx]), uiNumBytesToReadFromFifo); m_fifo_idx+=uiNumBytesToReadFromFifo; |
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378 | if (uiNumBytesToReadFromFifo != uiNumBytes) |
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379 | { |
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380 | memset(&(buf[currentOutputBufferSize+uiNumBytesToReadFromFifo]), 0, uiNumBytes - uiNumBytesToReadFromFifo); |
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381 | } |
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382 | } |
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383 | else |
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384 | { |
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385 | for (UInt ui = 0; ui < uiNumBytes; ui++) |
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386 | { |
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387 | UInt uiByte; |
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388 | read(8, uiByte); |
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389 | buf.push_back(uiByte); |
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390 | } |
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391 | } |
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392 | if (uiNumBits&0x7) |
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393 | { |
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394 | UInt uiByte = 0; |
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395 | read(uiNumBits&0x7, uiByte); |
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396 | uiByte <<= 8-(uiNumBits&0x7); |
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397 | buf.push_back(uiByte); |
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398 | } |
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399 | return pResult; |
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400 | } |
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401 | |
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402 | UInt TComInputBitstream::readByteAlignment() |
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403 | { |
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404 | UInt code = 0; |
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405 | read( 1, code ); |
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406 | assert(code == 1); |
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407 | |
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408 | UInt numBits = getNumBitsUntilByteAligned(); |
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409 | if(numBits) |
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410 | { |
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411 | assert(numBits <= getNumBitsLeft()); |
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412 | read( numBits, code ); |
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413 | assert(code == 0); |
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414 | } |
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415 | return numBits+1; |
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416 | } |
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417 | |
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418 | //! \} |
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