1 /******************************************************************** |
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2 * * |
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3 * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE. * |
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4 * * |
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5 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * |
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6 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * |
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7 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * |
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8 * * |
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9 * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002 * |
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10 * BY THE Xiph.Org FOUNDATION http://www.xiph.org/ * |
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11 * * |
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12 ******************************************************************** |
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13 |
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14 function: normalized modified discrete cosine transform |
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15 power of two length transform only [64 <= n ] |
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16 last mod: $Id: mdct.c,v 1.9 2002/10/16 09:17:39 xiphmont Exp $ |
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17 |
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18 Original algorithm adapted long ago from _The use of multirate filter |
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19 banks for coding of high quality digital audio_, by T. Sporer, |
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20 K. Brandenburg and B. Edler, collection of the European Signal |
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21 Processing Conference (EUSIPCO), Amsterdam, June 1992, Vol.1, pp |
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22 211-214 |
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23 |
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24 The below code implements an algorithm that no longer looks much like |
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25 that presented in the paper, but the basic structure remains if you |
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26 dig deep enough to see it. |
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27 |
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28 This module DOES NOT INCLUDE code to generate/apply the window |
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29 function. Everybody has their own weird favorite including me... I |
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30 happen to like the properties of y=sin(.5PI*sin^2(x)), but others may |
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31 vehemently disagree. |
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32 |
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33 ********************************************************************/ |
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34 |
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35 #include "ivorbiscodec.h" |
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36 #include "codebook.h" |
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37 #include "misc.h" |
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38 #include "mdct.h" |
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39 #include "mdct_lookup.h" |
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40 |
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41 |
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42 /* 8 point butterfly (in place) */ |
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43 STIN void mdct_butterfly_8(DATA_TYPE *x){ |
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44 |
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45 REG_TYPE r0 = x[4] + x[0]; |
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46 REG_TYPE r1 = x[4] - x[0]; |
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47 REG_TYPE r2 = x[5] + x[1]; |
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48 REG_TYPE r3 = x[5] - x[1]; |
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49 REG_TYPE r4 = x[6] + x[2]; |
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50 REG_TYPE r5 = x[6] - x[2]; |
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51 REG_TYPE r6 = x[7] + x[3]; |
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52 REG_TYPE r7 = x[7] - x[3]; |
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53 |
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54 x[0] = r5 + r3; |
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55 x[1] = r7 - r1; |
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56 x[2] = r5 - r3; |
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57 x[3] = r7 + r1; |
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58 x[4] = r4 - r0; |
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59 x[5] = r6 - r2; |
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60 x[6] = r4 + r0; |
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61 x[7] = r6 + r2; |
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62 MB(); |
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63 } |
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64 |
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65 /* 16 point butterfly (in place, 4 register) */ |
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66 STIN void mdct_butterfly_16(DATA_TYPE *x){ |
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67 |
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68 REG_TYPE r0, r1; |
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69 |
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70 r0 = x[ 0] - x[ 8]; x[ 8] += x[ 0]; |
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71 r1 = x[ 1] - x[ 9]; x[ 9] += x[ 1]; |
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72 x[ 0] = MULT31((r0 + r1) , cPI2_8); |
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73 x[ 1] = MULT31((r1 - r0) , cPI2_8); |
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74 MB(); |
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75 |
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76 r0 = x[10] - x[ 2]; x[10] += x[ 2]; |
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77 r1 = x[ 3] - x[11]; x[11] += x[ 3]; |
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78 x[ 2] = r1; x[ 3] = r0; |
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79 MB(); |
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80 |
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81 r0 = x[12] - x[ 4]; x[12] += x[ 4]; |
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82 r1 = x[13] - x[ 5]; x[13] += x[ 5]; |
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83 x[ 4] = MULT31((r0 - r1) , cPI2_8); |
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84 x[ 5] = MULT31((r0 + r1) , cPI2_8); |
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85 MB(); |
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86 |
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87 r0 = x[14] - x[ 6]; x[14] += x[ 6]; |
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88 r1 = x[15] - x[ 7]; x[15] += x[ 7]; |
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89 x[ 6] = r0; x[ 7] = r1; |
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90 MB(); |
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91 |
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92 mdct_butterfly_8(x); |
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93 mdct_butterfly_8(x+8); |
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94 } |
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95 |
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96 /* 32 point butterfly (in place, 4 register) */ |
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97 STIN void mdct_butterfly_32(DATA_TYPE *x){ |
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98 |
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99 REG_TYPE r0, r1; |
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100 |
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101 r0 = x[30] - x[14]; x[30] += x[14]; |
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102 r1 = x[31] - x[15]; x[31] += x[15]; |
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103 x[14] = r0; x[15] = r1; |
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104 MB(); |
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105 |
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106 r0 = x[28] - x[12]; x[28] += x[12]; |
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107 r1 = x[29] - x[13]; x[29] += x[13]; |
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108 XNPROD31( r0, r1, cPI1_8, cPI3_8, &x[12], &x[13] ); |
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109 MB(); |
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110 |
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111 r0 = x[26] - x[10]; x[26] += x[10]; |
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112 r1 = x[27] - x[11]; x[27] += x[11]; |
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113 x[10] = MULT31((r0 - r1) , cPI2_8); |
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114 x[11] = MULT31((r0 + r1) , cPI2_8); |
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115 MB(); |
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116 |
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117 r0 = x[24] - x[ 8]; x[24] += x[ 8]; |
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118 r1 = x[25] - x[ 9]; x[25] += x[ 9]; |
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119 XNPROD31( r0, r1, cPI3_8, cPI1_8, &x[ 8], &x[ 9] ); |
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120 MB(); |
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121 |
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122 r0 = x[22] - x[ 6]; x[22] += x[ 6]; |
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123 r1 = x[ 7] - x[23]; x[23] += x[ 7]; |
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124 x[ 6] = r1; x[ 7] = r0; |
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125 MB(); |
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126 |
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127 r0 = x[ 4] - x[20]; x[20] += x[ 4]; |
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128 r1 = x[ 5] - x[21]; x[21] += x[ 5]; |
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129 XPROD31 ( r0, r1, cPI3_8, cPI1_8, &x[ 4], &x[ 5] ); |
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130 MB(); |
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131 |
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132 r0 = x[ 2] - x[18]; x[18] += x[ 2]; |
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133 r1 = x[ 3] - x[19]; x[19] += x[ 3]; |
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134 x[ 2] = MULT31((r1 + r0) , cPI2_8); |
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135 x[ 3] = MULT31((r1 - r0) , cPI2_8); |
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136 MB(); |
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137 |
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138 r0 = x[ 0] - x[16]; x[16] += x[ 0]; |
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139 r1 = x[ 1] - x[17]; x[17] += x[ 1]; |
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140 XPROD31 ( r0, r1, cPI1_8, cPI3_8, &x[ 0], &x[ 1] ); |
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141 MB(); |
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142 |
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143 mdct_butterfly_16(x); |
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144 mdct_butterfly_16(x+16); |
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145 } |
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146 |
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147 /* N/stage point generic N stage butterfly (in place, 2 register) */ |
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148 STIN void mdct_butterfly_generic(DATA_TYPE *x,int points,int step){ |
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149 |
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150 LOOKUP_T *T = sincos_lookup0; |
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151 DATA_TYPE *x1 = x + points - 8; |
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152 DATA_TYPE *x2 = x + (points>>1) - 8; |
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153 REG_TYPE r0; |
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154 REG_TYPE r1; |
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155 |
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156 do{ |
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157 r0 = x1[6] - x2[6]; x1[6] += x2[6]; |
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158 r1 = x2[7] - x1[7]; x1[7] += x2[7]; |
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159 XPROD31( r1, r0, T[0], T[1], &x2[6], &x2[7] ); T+=step; |
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160 |
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161 r0 = x1[4] - x2[4]; x1[4] += x2[4]; |
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162 r1 = x2[5] - x1[5]; x1[5] += x2[5]; |
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163 XPROD31( r1, r0, T[0], T[1], &x2[4], &x2[5] ); T+=step; |
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164 |
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165 r0 = x1[2] - x2[2]; x1[2] += x2[2]; |
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166 r1 = x2[3] - x1[3]; x1[3] += x2[3]; |
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167 XPROD31( r1, r0, T[0], T[1], &x2[2], &x2[3] ); T+=step; |
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168 |
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169 r0 = x1[0] - x2[0]; x1[0] += x2[0]; |
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170 r1 = x2[1] - x1[1]; x1[1] += x2[1]; |
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171 XPROD31( r1, r0, T[0], T[1], &x2[0], &x2[1] ); T+=step; |
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172 |
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173 x1-=8; x2-=8; |
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174 }while(T<sincos_lookup0+1024); |
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175 do{ |
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176 r0 = x1[6] - x2[6]; x1[6] += x2[6]; |
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177 r1 = x1[7] - x2[7]; x1[7] += x2[7]; |
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178 XNPROD31( r0, r1, T[0], T[1], &x2[6], &x2[7] ); T-=step; |
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179 |
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180 r0 = x1[4] - x2[4]; x1[4] += x2[4]; |
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181 r1 = x1[5] - x2[5]; x1[5] += x2[5]; |
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182 XNPROD31( r0, r1, T[0], T[1], &x2[4], &x2[5] ); T-=step; |
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183 |
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184 r0 = x1[2] - x2[2]; x1[2] += x2[2]; |
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185 r1 = x1[3] - x2[3]; x1[3] += x2[3]; |
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186 XNPROD31( r0, r1, T[0], T[1], &x2[2], &x2[3] ); T-=step; |
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187 |
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188 r0 = x1[0] - x2[0]; x1[0] += x2[0]; |
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189 r1 = x1[1] - x2[1]; x1[1] += x2[1]; |
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190 XNPROD31( r0, r1, T[0], T[1], &x2[0], &x2[1] ); T-=step; |
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191 |
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192 x1-=8; x2-=8; |
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193 }while(T>sincos_lookup0); |
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194 do{ |
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195 r0 = x2[6] - x1[6]; x1[6] += x2[6]; |
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196 r1 = x2[7] - x1[7]; x1[7] += x2[7]; |
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197 XPROD31( r0, r1, T[0], T[1], &x2[6], &x2[7] ); T+=step; |
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198 |
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199 r0 = x2[4] - x1[4]; x1[4] += x2[4]; |
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200 r1 = x2[5] - x1[5]; x1[5] += x2[5]; |
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201 XPROD31( r0, r1, T[0], T[1], &x2[4], &x2[5] ); T+=step; |
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202 |
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203 r0 = x2[2] - x1[2]; x1[2] += x2[2]; |
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204 r1 = x2[3] - x1[3]; x1[3] += x2[3]; |
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205 XPROD31( r0, r1, T[0], T[1], &x2[2], &x2[3] ); T+=step; |
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206 |
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207 r0 = x2[0] - x1[0]; x1[0] += x2[0]; |
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208 r1 = x2[1] - x1[1]; x1[1] += x2[1]; |
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209 XPROD31( r0, r1, T[0], T[1], &x2[0], &x2[1] ); T+=step; |
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210 |
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211 x1-=8; x2-=8; |
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212 }while(T<sincos_lookup0+1024); |
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213 do{ |
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214 r0 = x1[6] - x2[6]; x1[6] += x2[6]; |
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215 r1 = x2[7] - x1[7]; x1[7] += x2[7]; |
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216 XNPROD31( r1, r0, T[0], T[1], &x2[6], &x2[7] ); T-=step; |
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217 |
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218 r0 = x1[4] - x2[4]; x1[4] += x2[4]; |
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219 r1 = x2[5] - x1[5]; x1[5] += x2[5]; |
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220 XNPROD31( r1, r0, T[0], T[1], &x2[4], &x2[5] ); T-=step; |
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221 |
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222 r0 = x1[2] - x2[2]; x1[2] += x2[2]; |
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223 r1 = x2[3] - x1[3]; x1[3] += x2[3]; |
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224 XNPROD31( r1, r0, T[0], T[1], &x2[2], &x2[3] ); T-=step; |
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225 |
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226 r0 = x1[0] - x2[0]; x1[0] += x2[0]; |
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227 r1 = x2[1] - x1[1]; x1[1] += x2[1]; |
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228 XNPROD31( r1, r0, T[0], T[1], &x2[0], &x2[1] ); T-=step; |
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229 |
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230 x1-=8; x2-=8; |
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231 }while(T>sincos_lookup0); |
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232 } |
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233 |
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234 STIN void mdct_butterflies(DATA_TYPE *x,int points,int shift){ |
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235 |
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236 int stages=8-shift; |
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237 int i,j; |
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238 |
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239 for(i=0;--stages>0;i++){ |
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240 for(j=0;j<(1<<i);j++) |
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241 mdct_butterfly_generic(x+(points>>i)*j,points>>i,4<<(i+shift)); |
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242 } |
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243 |
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244 for(j=0;j<points;j+=32) |
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245 mdct_butterfly_32(x+j); |
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246 |
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247 } |
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248 |
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249 static unsigned char bitrev[16]={0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15}; |
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250 |
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251 STIN int bitrev12(int x){ |
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252 return bitrev[x>>8]|(bitrev[(x&0x0f0)>>4]<<4)|(((int)bitrev[x&0x00f])<<8); |
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253 } |
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254 |
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255 STIN void mdct_bitreverse(DATA_TYPE *x,int n,int step,int shift){ |
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256 |
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257 int bit = 0; |
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258 DATA_TYPE *w0 = x; |
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259 DATA_TYPE *w1 = x = w0+(n>>1); |
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260 LOOKUP_T *T = (step>=4)?(sincos_lookup0+(step>>1)):sincos_lookup1; |
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261 LOOKUP_T *Ttop = T+1024; |
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262 DATA_TYPE r2; |
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263 |
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264 do{ |
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265 DATA_TYPE r3 = bitrev12(bit++); |
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266 DATA_TYPE *x0 = x + ((r3 ^ 0xfff)>>shift) -1; |
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267 DATA_TYPE *x1 = x + (r3>>shift); |
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268 |
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269 REG_TYPE r0 = x0[0] + x1[0]; |
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270 REG_TYPE r1 = x1[1] - x0[1]; |
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271 |
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272 XPROD32( r0, r1, T[1], T[0], &r2, &r3 ); T+=step; |
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273 |
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274 w1 -= 4; |
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275 |
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276 r0 = (x0[1] + x1[1])>>1; |
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277 r1 = (x0[0] - x1[0])>>1; |
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278 w0[0] = r0 + r2; |
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279 w0[1] = r1 + r3; |
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280 w1[2] = r0 - r2; |
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281 w1[3] = r3 - r1; |
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282 |
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283 r3 = bitrev12(bit++); |
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284 x0 = x + ((r3 ^ 0xfff)>>shift) -1; |
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285 x1 = x + (r3>>shift); |
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286 |
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287 r0 = x0[0] + x1[0]; |
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288 r1 = x1[1] - x0[1]; |
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289 |
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290 XPROD32( r0, r1, T[1], T[0], &r2, &r3 ); T+=step; |
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291 |
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292 r0 = (x0[1] + x1[1])>>1; |
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293 r1 = (x0[0] - x1[0])>>1; |
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294 w0[2] = r0 + r2; |
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295 w0[3] = r1 + r3; |
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296 w1[0] = r0 - r2; |
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297 w1[1] = r3 - r1; |
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298 |
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299 w0 += 4; |
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300 }while(T<Ttop); |
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301 do{ |
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302 DATA_TYPE r3 = bitrev12(bit++); |
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303 DATA_TYPE *x0 = x + ((r3 ^ 0xfff)>>shift) -1; |
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304 DATA_TYPE *x1 = x + (r3>>shift); |
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305 |
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306 REG_TYPE r0 = x0[0] + x1[0]; |
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307 REG_TYPE r1 = x1[1] - x0[1]; |
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308 |
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309 T-=step; XPROD32( r0, r1, T[0], T[1], &r2, &r3 ); |
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310 |
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311 w1 -= 4; |
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312 |
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313 r0 = (x0[1] + x1[1])>>1; |
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314 r1 = (x0[0] - x1[0])>>1; |
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315 w0[0] = r0 + r2; |
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316 w0[1] = r1 + r3; |
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317 w1[2] = r0 - r2; |
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318 w1[3] = r3 - r1; |
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319 |
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320 r3 = bitrev12(bit++); |
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321 x0 = x + ((r3 ^ 0xfff)>>shift) -1; |
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322 x1 = x + (r3>>shift); |
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323 |
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324 r0 = x0[0] + x1[0]; |
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325 r1 = x1[1] - x0[1]; |
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326 |
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327 T-=step; XPROD32( r0, r1, T[0], T[1], &r2, &r3 ); |
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328 |
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329 r0 = (x0[1] + x1[1])>>1; |
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330 r1 = (x0[0] - x1[0])>>1; |
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331 w0[2] = r0 + r2; |
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332 w0[3] = r1 + r3; |
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333 w1[0] = r0 - r2; |
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334 w1[1] = r3 - r1; |
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335 |
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336 w0 += 4; |
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337 }while(w0<w1); |
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338 } |
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339 |
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340 void mdct_backward(int n, DATA_TYPE *in, DATA_TYPE *out){ |
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341 int n2=n>>1; |
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342 int n4=n>>2; |
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343 DATA_TYPE *iX; |
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344 DATA_TYPE *oX; |
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345 LOOKUP_T *T; |
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346 LOOKUP_T *V; |
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347 int shift; |
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348 int step; |
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349 |
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350 for (shift=6;!(n&(1<<shift));shift++); |
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351 shift=13-shift; |
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352 step=2<<shift; |
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353 |
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354 /* rotate */ |
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355 |
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356 iX = in+n2-7; |
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357 oX = out+n2+n4; |
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358 T = sincos_lookup0; |
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359 |
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360 do{ |
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361 oX-=4; |
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362 XPROD31( iX[4], iX[6], T[0], T[1], &oX[2], &oX[3] ); T+=step; |
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363 XPROD31( iX[0], iX[2], T[0], T[1], &oX[0], &oX[1] ); T+=step; |
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364 iX-=8; |
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365 }while(iX>=in+n4); |
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366 do{ |
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367 oX-=4; |
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368 XPROD31( iX[4], iX[6], T[1], T[0], &oX[2], &oX[3] ); T-=step; |
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369 XPROD31( iX[0], iX[2], T[1], T[0], &oX[0], &oX[1] ); T-=step; |
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370 iX-=8; |
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371 }while(iX>=in); |
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372 |
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373 iX = in+n2-8; |
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374 oX = out+n2+n4; |
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375 T = sincos_lookup0; |
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376 |
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377 do{ |
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378 T+=step; XNPROD31( iX[6], iX[4], T[0], T[1], &oX[0], &oX[1] ); |
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379 T+=step; XNPROD31( iX[2], iX[0], T[0], T[1], &oX[2], &oX[3] ); |
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380 iX-=8; |
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381 oX+=4; |
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382 }while(iX>=in+n4); |
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383 do{ |
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384 T-=step; XNPROD31( iX[6], iX[4], T[1], T[0], &oX[0], &oX[1] ); |
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385 T-=step; XNPROD31( iX[2], iX[0], T[1], T[0], &oX[2], &oX[3] ); |
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386 iX-=8; |
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387 oX+=4; |
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388 }while(iX>=in); |
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389 |
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390 mdct_butterflies(out+n2,n2,shift); |
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391 mdct_bitreverse(out,n,step,shift); |
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392 |
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393 /* rotate + window */ |
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394 |
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395 step>>=2; |
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396 { |
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397 DATA_TYPE *oX1=out+n2+n4; |
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398 DATA_TYPE *oX2=out+n2+n4; |
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399 DATA_TYPE *iX =out; |
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400 |
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401 switch(step) { |
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402 default: { |
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403 T=(step>=4)?(sincos_lookup0+(step>>1)):sincos_lookup1; |
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404 do{ |
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405 oX1-=4; |
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406 XPROD31( iX[0], -iX[1], T[0], T[1], &oX1[3], &oX2[0] ); T+=step; |
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407 XPROD31( iX[2], -iX[3], T[0], T[1], &oX1[2], &oX2[1] ); T+=step; |
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408 XPROD31( iX[4], -iX[5], T[0], T[1], &oX1[1], &oX2[2] ); T+=step; |
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409 XPROD31( iX[6], -iX[7], T[0], T[1], &oX1[0], &oX2[3] ); T+=step; |
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410 oX2+=4; |
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411 iX+=8; |
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412 }while(iX<oX1); |
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413 break; |
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414 } |
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415 |
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416 case 1: { |
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417 /* linear interpolation between table values: offset=0.5, step=1 */ |
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418 REG_TYPE t0,t1,v0,v1; |
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419 T = sincos_lookup0; |
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420 V = sincos_lookup1; |
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421 t0 = (*T++)>>1; |
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422 t1 = (*T++)>>1; |
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423 do{ |
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424 oX1-=4; |
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425 |
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426 t0 += (v0 = (*V++)>>1); |
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427 t1 += (v1 = (*V++)>>1); |
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428 XPROD31( iX[0], -iX[1], t0, t1, &oX1[3], &oX2[0] ); |
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429 v0 += (t0 = (*T++)>>1); |
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430 v1 += (t1 = (*T++)>>1); |
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431 XPROD31( iX[2], -iX[3], v0, v1, &oX1[2], &oX2[1] ); |
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432 t0 += (v0 = (*V++)>>1); |
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433 t1 += (v1 = (*V++)>>1); |
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434 XPROD31( iX[4], -iX[5], t0, t1, &oX1[1], &oX2[2] ); |
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435 v0 += (t0 = (*T++)>>1); |
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436 v1 += (t1 = (*T++)>>1); |
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437 XPROD31( iX[6], -iX[7], v0, v1, &oX1[0], &oX2[3] ); |
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438 |
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439 oX2+=4; |
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440 iX+=8; |
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441 }while(iX<oX1); |
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442 break; |
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443 } |
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444 |
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445 case 0: { |
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446 /* linear interpolation between table values: offset=0.25, step=0.5 */ |
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447 REG_TYPE t0,t1,v0,v1,q0,q1; |
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448 T = sincos_lookup0; |
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449 V = sincos_lookup1; |
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450 t0 = *T++; |
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451 t1 = *T++; |
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452 do{ |
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453 oX1-=4; |
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454 |
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455 v0 = *V++; |
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456 v1 = *V++; |
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457 t0 += (q0 = (v0-t0)>>2); |
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458 t1 += (q1 = (v1-t1)>>2); |
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459 XPROD31( iX[0], -iX[1], t0, t1, &oX1[3], &oX2[0] ); |
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460 t0 = v0-q0; |
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461 t1 = v1-q1; |
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462 XPROD31( iX[2], -iX[3], t0, t1, &oX1[2], &oX2[1] ); |
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463 |
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464 t0 = *T++; |
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465 t1 = *T++; |
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466 v0 += (q0 = (t0-v0)>>2); |
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467 v1 += (q1 = (t1-v1)>>2); |
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468 XPROD31( iX[4], -iX[5], v0, v1, &oX1[1], &oX2[2] ); |
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469 v0 = t0-q0; |
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470 v1 = t1-q1; |
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471 XPROD31( iX[6], -iX[7], v0, v1, &oX1[0], &oX2[3] ); |
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472 |
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473 oX2+=4; |
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474 iX+=8; |
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475 }while(iX<oX1); |
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476 break; |
|
477 } |
|
478 } |
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479 |
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480 iX=out+n2+n4; |
|
481 oX1=out+n4; |
|
482 oX2=oX1; |
|
483 |
|
484 do{ |
|
485 oX1-=4; |
|
486 iX-=4; |
|
487 |
|
488 oX2[0] = -(oX1[3] = iX[3]); |
|
489 oX2[1] = -(oX1[2] = iX[2]); |
|
490 oX2[2] = -(oX1[1] = iX[1]); |
|
491 oX2[3] = -(oX1[0] = iX[0]); |
|
492 |
|
493 oX2+=4; |
|
494 }while(oX2<iX); |
|
495 |
|
496 iX=out+n2+n4; |
|
497 oX1=out+n2+n4; |
|
498 oX2=out+n2; |
|
499 |
|
500 do{ |
|
501 oX1-=4; |
|
502 oX1[0]= iX[3]; |
|
503 oX1[1]= iX[2]; |
|
504 oX1[2]= iX[1]; |
|
505 oX1[3]= iX[0]; |
|
506 iX+=4; |
|
507 }while(oX1>oX2); |
|
508 } |
|
509 } |
|
510 |
|