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1 /* |
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2 * Copyright (c) 2010 Ixonos Plc. |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of the "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - Initial contribution |
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11 * |
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12 * Contributors: |
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13 * Ixonos Plc |
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14 * |
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15 * Description: |
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16 * |
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17 */ |
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18 |
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19 |
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20 /************************************************************************** |
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21 l3huffman.cpp - Huffman decoding subroutines for layer III. |
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22 |
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23 Author(s): Juha Ojanpera |
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24 Copyright (c) 1999-2004 by Nokia Research Center, Speech and Audio Systems. |
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25 *************************************************************************/ |
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26 |
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27 /************************************************************************** |
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28 External Objects Needed |
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29 *************************************************************************/ |
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30 |
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31 /*-- Project Headers --*/ |
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32 #include "mpaud.h" |
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33 #include "mp3tables.h" |
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34 |
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35 /************************************************************************** |
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36 Internal Objects |
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37 *************************************************************************/ |
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38 |
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39 /* |
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40 Purpose: Table to hold the Huffman symbol codebooks. |
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41 Explanation: - |
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42 const int16 *huff_symbols_tbl[] = { |
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43 NULL, huff_symbols1, huff_symbols2, huff_symbols3, NULL, huff_symbols5, |
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44 huff_symbols6, huff_symbols7, huff_symbols8, huff_symbols9, huff_symbols10, |
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45 huff_symbols11, huff_symbols12, huff_symbols13, NULL, huff_symbols15, |
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46 huff_symbols16, huff_symbols24, huff_symbols32}; |
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47 |
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48 |
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49 Purpose: Table to hold the Huffman codeword codebooks. |
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50 Explanation: - |
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51 |
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52 const int16 *huff_cwords_tbl[] = { |
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53 NULL, huff_cwords1, huff_cwords2, huff_cwords3, NULL, huff_cwords5, |
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54 huff_cwords6, huff_cwords7, huff_cwords8, huff_cwords9, huff_cwords10, |
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55 huff_cwords11, huff_cwords12, huff_cwords13, NULL, huff_cwords15, huff_cwords16, |
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56 huff_cwords24, huff_cwords32}; |
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57 */ |
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58 |
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59 /************************************************************************** |
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60 Title : InitL3Huffman |
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61 |
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62 Purpose : Allocates resources for layer III Huffman decoding. |
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63 |
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64 Usage : InitL3Huffman(huf) |
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65 |
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66 Output : huf - Huffman tables |
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67 |
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68 Author(s) : Juha Ojanpera |
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69 *************************************************************************/ |
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70 |
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71 void |
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72 InitL3Huffman(CHuffman *huf) |
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73 { |
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74 int16 i, j; |
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75 |
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76 |
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77 /* |
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78 Purpose: Table to hold the Huffman symbol codebooks. |
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79 Explanation: - */ |
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80 const int16 *huff_symbols_tbl[] = { |
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81 NULL, huff_symbols1, huff_symbols2, huff_symbols3, NULL, huff_symbols5, |
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82 huff_symbols6, huff_symbols7, huff_symbols8, huff_symbols9, huff_symbols10, |
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83 huff_symbols11, huff_symbols12, huff_symbols13, NULL, huff_symbols15, |
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84 huff_symbols16, huff_symbols24, huff_symbols32}; |
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85 |
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86 /* |
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87 Purpose: Table to hold the Huffman codeword codebooks. |
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88 Explanation: - */ |
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89 const int16 *huff_cwords_tbl[] = { |
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90 NULL, huff_cwords1, huff_cwords2, huff_cwords3, NULL, huff_cwords5, |
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91 huff_cwords6, huff_cwords7, huff_cwords8, huff_cwords9, huff_cwords10, |
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92 huff_cwords11, huff_cwords12, huff_cwords13, NULL, huff_cwords15, huff_cwords16, |
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93 huff_cwords24, huff_cwords32}; |
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94 |
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95 |
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96 for(i = 0; i < 33; i++) |
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97 { |
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98 huf[i].tree_len = huf_tree_len[i]; |
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99 huf[i].linbits = linbits[i]; |
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100 } |
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101 |
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102 for(i = 0; i < 16; i++) |
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103 { |
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104 huf[i].codeword = huff_cwords_tbl[i]; |
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105 huf[i].packed_symbols = huff_symbols_tbl[i]; |
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106 } |
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107 |
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108 j = i; |
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109 while(j < 24) |
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110 { |
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111 huf[j].codeword = huff_cwords_tbl[i]; |
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112 huf[j].packed_symbols = huff_symbols_tbl[i]; |
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113 j++; |
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114 } |
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115 |
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116 i++; |
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117 while(j < 32) |
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118 { |
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119 huf[j].codeword = huff_cwords_tbl[i]; |
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120 huf[j].packed_symbols = huff_symbols_tbl[i]; |
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121 j++; |
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122 } |
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123 |
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124 i++; |
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125 huf[j].codeword = huff_cwords_tbl[i]; |
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126 huf[j].packed_symbols = huff_symbols_tbl[i]; |
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127 } |
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128 |
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129 |
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130 /************************************************************************** |
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131 Title : L3decode_codeword |
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132 |
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133 Purpose : Decodes one Huffman codeword from the bitstream and returns |
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134 the corresponding symbol. |
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135 |
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136 Usage : L3decode_codeword(br, h) |
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137 |
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138 Input : br - bitstream parameters |
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139 h - Huffman table to be utilized |
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140 |
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141 Explanation : This decoding routine works only if the codewords are |
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142 sorted according to their length, i.e, the codeword that has |
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143 the minimum length appears first in the Huffman table, the |
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144 length of the second codeword in the table is either greater |
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145 or equal than the first one and so on. |
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146 |
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147 Author(s) : Juha Ojanpera |
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148 *************************************************************************/ |
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149 |
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150 INLINE int16 |
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151 L3decode_codeword(TBitStream *br, CHuffman *h) |
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152 { |
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153 const int16 *h_len = h->packed_symbols; |
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154 const int16 *h_codeword = h->codeword; |
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155 uint16 clen, items; |
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156 uint16 shift, N = 19; /* N = 19 maximum codeword length */ |
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157 uint32 cand_codeword; |
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158 uint32 codeword; |
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159 |
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160 /* Read the maximum codeword. */ |
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161 cand_codeword = BsLookAhead(br, N); |
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162 |
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163 /* |
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164 * Length of the codeword that has the |
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165 * highest probability. |
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166 */ |
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167 shift = N - (*h_len & 31); |
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168 |
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169 /* Candidate codeword for the first codebook entry. */ |
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170 codeword = cand_codeword >> shift; |
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171 |
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172 /* |
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173 * Sequentially goes through the whole Huffman table |
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174 * until a match has been found. |
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175 */ |
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176 items = 1; |
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177 while(items < h->tree_len && codeword != (uint16)*h_codeword) |
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178 { |
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179 h_len++; |
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180 h_codeword++; |
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181 items++; |
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182 |
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183 /* How many bits the codeword need to be updated. */ |
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184 clen = *h_len & 31; |
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185 if(clen) |
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186 { |
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187 shift -= clen; |
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188 |
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189 /* New candidate codeword. */ |
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190 codeword = cand_codeword >> shift; |
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191 } |
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192 } |
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193 |
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194 /* # of bits actually read. */ |
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195 BsSkipNBits(br, N - shift); |
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196 |
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197 /* Decoded Huffman symbol. */ |
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198 return (*h_len >> 5); |
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199 } |
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200 |
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201 /************************************************************************** |
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202 Layer III subroutines for decoding spectral samples. |
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203 |
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204 Author(s): Juha Ojanpera |
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205 Copyright (c) 1999-2004 by Nokia Research Center, Speech and Audio Systems. |
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206 *************************************************************************/ |
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207 |
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208 int16 |
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209 III_huffman_decode(CMP_Stream *mp, int16 gr, int16 ch, int32 part2) |
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210 { |
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211 int16 i, x, region1Start, region2Start, table_num, limit; |
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212 int16 *quant, count1Len; |
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213 TGranule_Info *gr_info; |
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214 |
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215 /* Quantized spectral samples. */ |
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216 quant = mp->frame->ch_quant[ch]; |
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217 |
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218 /* Granule info for this frame. */ |
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219 gr_info = mp->side_info->ch_info[ch]->gr_info[gr]; |
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220 |
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221 /* Find region boundaries. */ |
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222 region1Start = mp->side_info->sfbData->sfbLong[gr_info->region0_count + 1]; |
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223 region2Start = mp->side_info->sfbData->sfbLong[gr_info->region0_count + |
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224 gr_info->region1_count + 2]; |
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225 |
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226 /* |
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227 * How many samples actually need to be Huffman decoded. |
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228 */ |
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229 limit = mp->side_info->sfbData->bandLimit; |
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230 if(gr_info->big_values > limit) |
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231 gr_info->big_values = limit; |
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232 |
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233 /* Read bigvalues area. */ |
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234 int16 section1 = MIN(gr_info->big_values, region1Start); |
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235 if(section1 > 0) |
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236 { |
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237 pairtable(mp, section1, gr_info->table_select[0], quant); |
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238 quant += section1; |
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239 } |
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240 |
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241 int16 section2 = MIN(gr_info->big_values, region2Start) - region1Start; |
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242 if(section2 > 0) |
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243 { |
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244 pairtable(mp, section2, gr_info->table_select[1], quant); |
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245 quant += section2; |
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246 } |
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247 |
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248 int16 section3 = gr_info->big_values - region2Start; |
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249 if(section3 > 0) |
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250 { |
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251 pairtable(mp, section3, gr_info->table_select[2], quant); |
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252 quant += section3; |
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253 } |
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254 |
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255 count1Len = 0; |
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256 i = gr_info->big_values; |
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257 part2 += gr_info->part2_3_length; |
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258 |
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259 /* Check whether the samples between -1,...,1 need to be Huffman decoded. */ |
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260 if(i < limit) |
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261 { |
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262 /* Read count1 area. */ |
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263 table_num = 32 + ((gr_info->flags & COUNT_1_TABLE_SELECT) ? 1 : 0); |
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264 |
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265 x = quadtable(mp, i, part2, table_num, quant, limit); |
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266 count1Len = x - i; |
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267 quant += count1Len; |
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268 count1Len >>= 2; |
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269 i = x; |
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270 } |
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271 |
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272 if(BsGetBitsRead(mp->br) > (uint32)part2) |
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273 { |
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274 count1Len--; |
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275 quant -= 4; i -= 4; |
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276 BsRewindNBits(mp->br, BsGetBitsRead(mp->br) - part2); |
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277 } |
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278 |
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279 /* Dismiss stuffing Bits */ |
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280 if(BsGetBitsRead(mp->br) < (uint32)part2) |
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281 BsSkipNBits(mp->br, part2 - BsGetBitsRead(mp->br)); |
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282 |
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283 gr_info->zero_part_start = (i < limit) ? i : limit; |
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284 |
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285 return (count1Len); |
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286 } |
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287 |
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288 void |
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289 pairtable(CMP_Stream *mp, int16 section_length, int16 table_num, int16 *quant) |
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290 { |
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291 register CHuffman *h = &mp->huffman[table_num]; |
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292 |
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293 if(h->tree_len == 0) |
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294 Mem::Fill(quant, section_length << 1 /** sizeof(int16)*/, 0); |
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295 else |
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296 { |
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297 if(h->linbits) |
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298 { |
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299 register int16 *q = quant; |
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300 |
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301 for(int16 i = 0; i < section_length; i += 2, q += 2) |
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302 { |
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303 uint32 codeword = L3decode_codeword(mp->br, h); |
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304 |
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305 /* Unpack coefficients. */ |
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306 *q = codeword >> 4; |
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307 q[1] = codeword & 15; |
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308 |
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309 /* Read extra bits (if needed) and sign bits (if needed). */ |
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310 if(*q == 15) |
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311 *q += BsGetBits(mp->br, h->linbits); |
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312 if(*q) |
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313 *q = (BsGetBits(mp->br, 1)) ? -*q : *q; |
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314 |
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315 if(q[1] == 15) |
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316 q[1] += BsGetBits(mp->br, h->linbits); |
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317 if(q[1]) |
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318 q[1] = (BsGetBits(mp->br, 1)) ? -q[1] : q[1]; |
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319 } |
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320 } |
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321 else /* no linbits */ |
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322 { |
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323 register int16 *q = quant; |
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324 |
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325 for(int16 i = 0; i < section_length; i += 2, q += 2) |
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326 { |
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327 uint32 codeword = L3decode_codeword(mp->br, h); |
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328 |
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329 /* Unpack coefficients. */ |
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330 *q = codeword >> 4; |
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331 q[1] = codeword & 15; |
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332 |
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333 /* Read extra bits (not needed) and sign bits (if needed). */ |
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334 if(*q) |
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335 *q = (BsGetBits(mp->br, 1)) ? -*q : *q; |
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336 |
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337 if(q[1]) |
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338 q[1] = (BsGetBits(mp->br, 1)) ? -q[1] : q[1]; |
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339 } |
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340 } |
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341 } |
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342 } |
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343 |
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344 int16 |
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345 quadtable(CMP_Stream *mp, int16 start, int16 part2, int16 table_num, int16 *quant, |
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346 int16 max_sfb_bins) |
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347 { |
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348 int16 i; |
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349 register int16 *q = quant; |
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350 |
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351 for(i = start; (BsGetBitsRead(mp->br) < (uint32)part2 && i < max_sfb_bins); |
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352 i += 4, q += 4) |
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353 { |
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354 uint32 codeword; |
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355 uint16 mask = 8, sbits = 0; |
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356 |
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357 if(table_num == 33) |
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358 codeword = 15 - BsGetBits(mp->br, 4); |
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359 else |
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360 codeword = L3decode_codeword(mp->br, &mp->huffman[table_num]); |
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361 |
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362 /* Unpack coefficients. */ |
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363 *q = (codeword >> 3) & 1; |
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364 q[1] = (codeword >> 2) & 1; |
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365 q[2] = (codeword >> 1) & 1; |
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366 q[3] = codeword & 1; |
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367 |
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368 /* Sign bits. */ |
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369 codeword = BsLookAhead(mp->br, 4); |
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370 if(*q) { sbits++; *q = (codeword & mask) ? -*q : *q; mask >>= 1; } |
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371 if(q[1]) { sbits++; q[1] = (codeword & mask) ? -q[1] : q[1]; mask >>= 1; } |
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372 if(q[2]) { sbits++; q[2] = (codeword & mask) ? -q[2] : q[2]; mask >>= 1; } |
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373 if(q[3]) { sbits++; q[3] = (codeword & mask) ? -q[3] : q[3]; mask >>= 1; } |
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374 if(sbits) BsSkipBits(mp->br, sbits); |
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375 } |
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376 |
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377 return (i); |
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378 } |