## ffmpeg / libavcodec / liba52 / bit_allocate.c @ 5509bffa

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1 | 976f969b | Zdenek Kabelac | ```
/*
``` |
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2 | ```
* bit_allocate.c
``` |
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3 | c947dec9 | Zdenek Kabelac | ```
* Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
``` |

4 | 976f969b | Zdenek Kabelac | ```
* Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
``` |

5 | ```
*
``` |
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6 | ```
* This file is part of a52dec, a free ATSC A-52 stream decoder.
``` |
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7 | ```
* See http://liba52.sourceforge.net/ for updates.
``` |
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8 | ```
*
``` |
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9 | ```
* a52dec is free software; you can redistribute it and/or modify
``` |
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10 | ```
* it under the terms of the GNU General Public License as published by
``` |
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11 | ```
* the Free Software Foundation; either version 2 of the License, or
``` |
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12 | ```
* (at your option) any later version.
``` |
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13 | ```
*
``` |
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14 | ```
* a52dec is distributed in the hope that it will be useful,
``` |
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15 | ```
* but WITHOUT ANY WARRANTY; without even the implied warranty of
``` |
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16 | ```
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
``` |
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17 | ```
* GNU General Public License for more details.
``` |
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18 | ```
*
``` |
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19 | ```
* You should have received a copy of the GNU General Public License
``` |
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20 | ```
* along with this program; if not, write to the Free Software
``` |
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21 | 5509bffa | Diego Biurrun | ```
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
``` |

22 | 976f969b | Zdenek Kabelac | ```
*/
``` |

23 | #include "a52.h" |
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24 | #include "a52_internal.h" |
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25 | |||

26 | static int hthtab[3][50] = { |
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27 | {0x730, 0x730, 0x7c0, 0x800, 0x820, 0x840, 0x850, 0x850, 0x860, 0x860, |
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28 | 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x890, 0x890, |
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29 | 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900, |
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30 | 0x910, 0x910, 0x910, 0x910, 0x900, 0x8f0, 0x8c0, 0x870, 0x820, 0x7e0, |
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31 | 0x7a0, 0x770, 0x760, 0x7a0, 0x7c0, 0x7c0, 0x6e0, 0x400, 0x3c0, 0x3c0}, |
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32 | {0x710, 0x710, 0x7a0, 0x7f0, 0x820, 0x830, 0x840, 0x850, 0x850, 0x860, |
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33 | 0x860, 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880, |
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34 | 0x890, 0x890, 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8e0, 0x8f0, |
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35 | 0x900, 0x910, 0x910, 0x910, 0x910, 0x900, 0x8e0, 0x8b0, 0x870, 0x820, |
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36 | 0x7e0, 0x7b0, 0x760, 0x770, 0x7a0, 0x7c0, 0x780, 0x5d0, 0x3c0, 0x3c0}, |
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37 | {0x680, 0x680, 0x750, 0x7b0, 0x7e0, 0x810, 0x820, 0x830, 0x840, 0x850, |
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38 | 0x850, 0x850, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, |
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39 | 0x870, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880, 0x890, 0x8a0, 0x8b0, |
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40 | 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900, 0x910, 0x910, 0x910, 0x900, 0x8f0, |
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41 | 0x8d0, 0x8b0, 0x840, 0x7f0, 0x790, 0x760, 0x7a0, 0x7c0, 0x7b0, 0x720} |
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42 | }; |
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43 | |||

44 | static int8_t baptab[305] = { |
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45 | 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, |
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46 | 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, |
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47 | 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, |
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48 | 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, |
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49 | 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, |
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50 | 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, /* 93 padding elems */ |
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51 | |||

52 | 16, 16, 16, 16, 16, 16, 16, 16, 16, 14, 14, 14, 14, 14, 14, 14, |
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53 | 14, 12, 12, 12, 12, 11, 11, 11, 11, 10, 10, 10, 10, 9, 9, 9, |
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54 | 9, 8, 8, 8, 8, 7, 7, 7, 7, 6, 6, 6, 6, 5, 5, 5, |
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55 | 5, 4, 4, -3, -3, 3, 3, 3, -2, -2, -1, -1, -1, -1, -1, 0, |
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56 | |||

57 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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58 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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59 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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60 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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61 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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62 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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63 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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64 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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65 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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66 | 0, 0, 0, 0 /* 148 padding elems */ |
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67 | }; |
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68 | |||

69 | static int bndtab[30] = {21, 22, 23, 24, 25, 26, 27, 28, 31, 34, |
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70 | 37, 40, 43, 46, 49, 55, 61, 67, 73, 79, |
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71 | 85, 97, 109, 121, 133, 157, 181, 205, 229, 253}; |
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72 | |||

73 | static int8_t latab[256] = { |
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74 | -64, -63, -62, -61, -60, -59, -58, -57, -56, -55, -54, -53, |
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75 | -52, -52, -51, -50, -49, -48, -47, -47, -46, -45, -44, -44, |
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76 | -43, -42, -41, -41, -40, -39, -38, -38, -37, -36, -36, -35, |
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77 | -35, -34, -33, -33, -32, -32, -31, -30, -30, -29, -29, -28, |
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78 | -28, -27, -27, -26, -26, -25, -25, -24, -24, -23, -23, -22, |
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79 | -22, -21, -21, -21, -20, -20, -19, -19, -19, -18, -18, -18, |
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80 | -17, -17, -17, -16, -16, -16, -15, -15, -15, -14, -14, -14, |
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81 | -13, -13, -13, -13, -12, -12, -12, -12, -11, -11, -11, -11, |
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82 | -10, -10, -10, -10, -10, -9, -9, -9, -9, -9, -8, -8, |
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83 | -8, -8, -8, -8, -7, -7, -7, -7, -7, -7, -6, -6, |
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84 | -6, -6, -6, -6, -6, -6, -5, -5, -5, -5, -5, -5, |
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85 | -5, -5, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, |
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86 | -4, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, |
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87 | -3, -3, -3, -2, -2, -2, -2, -2, -2, -2, -2, -2, |
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88 | -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -1, |
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89 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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90 | -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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91 | -1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0, |
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92 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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93 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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94 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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95 | 0, 0, 0, 0 |
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96 | }; |
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97 | |||

98 | ```
#define UPDATE_LEAK() \
``` |
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99 | ```
do { \
``` |
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100 | fastleak += fdecay; \ |
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101 | ```
if (fastleak > psd + fgain) \
``` |
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102 | fastleak = psd + fgain; \ |
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103 | slowleak += sdecay; \ |
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104 | ```
if (slowleak > psd + sgain) \
``` |
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105 | slowleak = psd + sgain; \ |
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106 | } while (0) |
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107 | |||

108 | ```
#define COMPUTE_MASK() \
``` |
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109 | ```
do { \
``` |
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110 | ```
if (psd > dbknee) \
``` |
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111 | ```
mask -= (psd - dbknee) >> 2; \
``` |
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112 | ```
if (mask > hth [i >> halfrate]) \
``` |
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113 | mask = hth [i >> halfrate]; \ |
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114 | ```
mask -= snroffset + 128 * deltba[i]; \
``` |
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115 | mask = (mask > 0) ? 0 : ((-mask) >> 5); \ |
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116 | mask -= floor; \ |
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117 | } while (0) |
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118 | |||

119 | void a52_bit_allocate (a52_state_t * state, ba_t * ba, int bndstart, |
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120 | int start, int end, int fastleak, int slowleak, |
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121 | expbap_t * expbap) |
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122 | { |
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123 | static int slowgain[4] = {0x540, 0x4d8, 0x478, 0x410}; |
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124 | static int dbpbtab[4] = {0xc00, 0x500, 0x300, 0x100}; |
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125 | static int floortab[8] = {0x910, 0x950, 0x990, 0x9d0, |
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126 | 0xa10, 0xa90, 0xb10, 0x1400}; |
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127 | |||

128 | ```
int i, j;
``` |
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129 | uint8_t * exp; |
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130 | int8_t * bap; |
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131 | ```
int fdecay, fgain, sdecay, sgain, dbknee, floor, snroffset;
``` |
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132 | ```
int psd, mask;
``` |
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133 | int8_t * deltba; |
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134 | ```
int * hth;
``` |
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135 | ```
int halfrate;
``` |
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136 | |||

137 | halfrate = state->halfrate; |
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138 | fdecay = (63 + 20 * ((state->bai >> 7) & 3)) >> halfrate; /* fdcycod */ |
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139 | fgain = 128 + 128 * (ba->bai & 7); /* fgaincod */ |
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140 | sdecay = (15 + 2 * (state->bai >> 9)) >> halfrate; /* sdcycod */ |
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141 | sgain = slowgain[(state->bai >> 5) & 3]; /* sgaincod */ |
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142 | dbknee = dbpbtab[(state->bai >> 3) & 3]; /* dbpbcod */ |
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143 | hth = hthtab[state->fscod]; |
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144 | ```
/*
``` |
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145 | ```
* if there is no delta bit allocation, make deltba point to an area
``` |
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146 | ```
* known to contain zeroes. baptab+156 here.
``` |
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147 | ```
*/
``` |
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148 | ```
deltba = (ba->deltbae == DELTA_BIT_NONE) ? baptab + 156 : ba->deltba;
``` |
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149 | floor = floortab[state->bai & 7]; /* floorcod */ |
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150 | snroffset = 960 - 64 * state->csnroffst - 4 * (ba->bai >> 3) + floor; |
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151 | ```
floor >>= 5;
``` |
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152 | |||

153 | exp = expbap->exp; |
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154 | bap = expbap->bap; |
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155 | |||

156 | i = bndstart; |
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157 | j = start; |
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158 | if (start == 0) { /* not the coupling channel */ |
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159 | ```
int lowcomp;
``` |
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160 | |||

161 | ```
lowcomp = 0;
``` |
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162 | ```
j = end - 1;
``` |
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163 | ```
do {
``` |
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164 | ```
if (i < j) {
``` |
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165 | if (exp[i+1] == exp[i] - 2) |
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166 | ```
lowcomp = 384;
``` |
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167 | else if (lowcomp && (exp[i+1] > exp[i])) |
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168 | ```
lowcomp -= 64;
``` |
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169 | } |
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170 | ```
psd = 128 * exp[i];
``` |
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171 | mask = psd + fgain + lowcomp; |
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172 | COMPUTE_MASK (); |
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173 | bap[i] = (baptab+156)[mask + 4 * exp[i]]; |
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174 | i++; |
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175 | } while ((i < 3) || ((i < 7) && (exp[i] > exp[i-1]))); |
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176 | fastleak = psd + fgain; |
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177 | slowleak = psd + sgain; |
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178 | |||

179 | while (i < 7) { |
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180 | ```
if (i < j) {
``` |
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181 | if (exp[i+1] == exp[i] - 2) |
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182 | ```
lowcomp = 384;
``` |
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183 | else if (lowcomp && (exp[i+1] > exp[i])) |
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184 | ```
lowcomp -= 64;
``` |
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185 | } |
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186 | ```
psd = 128 * exp[i];
``` |
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187 | UPDATE_LEAK (); |
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188 | mask = ((fastleak + lowcomp < slowleak) ? |
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189 | fastleak + lowcomp : slowleak); |
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190 | COMPUTE_MASK (); |
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191 | bap[i] = (baptab+156)[mask + 4 * exp[i]]; |
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192 | i++; |
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193 | } |
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194 | |||

195 | if (end == 7) /* lfe channel */ |
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196 | ```
return;
``` |
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197 | |||

198 | ```
do {
``` |
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199 | if (exp[i+1] == exp[i] - 2) |
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200 | ```
lowcomp = 320;
``` |
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201 | else if (lowcomp && (exp[i+1] > exp[i])) |
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202 | ```
lowcomp -= 64;
``` |
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203 | ```
psd = 128 * exp[i];
``` |
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204 | UPDATE_LEAK (); |
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205 | mask = ((fastleak + lowcomp < slowleak) ? |
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206 | fastleak + lowcomp : slowleak); |
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207 | COMPUTE_MASK (); |
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208 | bap[i] = (baptab+156)[mask + 4 * exp[i]]; |
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209 | i++; |
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210 | } while (i < 20); |
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211 | |||

212 | while (lowcomp > 128) { /* two iterations maximum */ |
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213 | ```
lowcomp -= 128;
``` |
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214 | ```
psd = 128 * exp[i];
``` |
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215 | UPDATE_LEAK (); |
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216 | mask = ((fastleak + lowcomp < slowleak) ? |
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217 | fastleak + lowcomp : slowleak); |
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218 | COMPUTE_MASK (); |
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219 | bap[i] = (baptab+156)[mask + 4 * exp[i]]; |
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220 | i++; |
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221 | } |
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222 | j = i; |
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223 | } |
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224 | |||

225 | ```
do {
``` |
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226 | ```
int startband, endband;
``` |
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227 | |||

228 | startband = j; |
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229 | c947dec9 | Zdenek Kabelac | endband = (bndtab[i-20] < end) ? bndtab[i-20] : end; |

230 | 976f969b | Zdenek Kabelac | ```
psd = 128 * exp[j++];
``` |

231 | ```
while (j < endband) {
``` |
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232 | ```
int next, delta;
``` |
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233 | |||

234 | ```
next = 128 * exp[j++];
``` |
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235 | delta = next - psd; |
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236 | switch (delta >> 9) { |
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237 | case -6: case -5: case -4: case -3: case -2: |
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238 | psd = next; |
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239 | ```
break;
``` |
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240 | case -1: |
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241 | ```
psd = next + latab[(-delta) >> 1];
``` |
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242 | ```
break;
``` |
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243 | case 0: |
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244 | ```
psd += latab[delta >> 1];
``` |
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245 | ```
break;
``` |
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246 | } |
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247 | } |
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248 | ```
/* minpsd = -289 */
``` |
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249 | UPDATE_LEAK (); |
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250 | mask = (fastleak < slowleak) ? fastleak : slowleak; |
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251 | COMPUTE_MASK (); |
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252 | i++; |
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253 | j = startband; |
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254 | ```
do {
``` |
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255 | ```
/* max(mask+4*exp)=147=-(minpsd+fgain-deltba-snroffset)>>5+4*exp */
``` |
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256 | ```
/* min(mask+4*exp)=-156=-(sgain-deltba-snroffset)>>5 */
``` |
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257 | bap[j] = (baptab+156)[mask + 4 * exp[j]]; |
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258 | ```
} while (++j < endband);
``` |
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259 | ```
} while (j < end);
``` |
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260 | } |