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Rev | Author | Line No. | Line |
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4349 | Serge | 1 | /* |
2 | * gsm 06.10 decoder |
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3 | * Copyright (c) 2010 Reimar Döffinger |
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4 | * |
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5 | * This file is part of FFmpeg. |
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6 | * |
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7 | * FFmpeg is free software; you can redistribute it and/or |
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8 | * modify it under the terms of the GNU Lesser General Public |
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9 | * License as published by the Free Software Foundation; either |
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10 | * version 2.1 of the License, or (at your option) any later version. |
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11 | * |
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12 | * FFmpeg is distributed in the hope that it will be useful, |
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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15 | * Lesser General Public License for more details. |
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16 | * |
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17 | * You should have received a copy of the GNU Lesser General Public |
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18 | * License along with FFmpeg; if not, write to the Free Software |
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19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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20 | */ |
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21 | |||
22 | /** |
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23 | * @file |
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24 | * GSM decoder |
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25 | */ |
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26 | |||
27 | #include "get_bits.h" |
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28 | #include "gsm.h" |
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29 | #include "gsmdec_data.h" |
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30 | |||
31 | static void apcm_dequant_add(GetBitContext *gb, int16_t *dst) |
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32 | { |
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33 | int i; |
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34 | int maxidx = get_bits(gb, 6); |
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35 | const int16_t *tab = ff_gsm_dequant_tab[maxidx]; |
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36 | for (i = 0; i < 13; i++) |
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37 | dst[3*i] += tab[get_bits(gb, 3)]; |
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38 | } |
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39 | |||
40 | static inline int gsm_mult(int a, int b) |
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41 | { |
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42 | return (a * b + (1 << 14)) >> 15; |
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43 | } |
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44 | |||
45 | static void long_term_synth(int16_t *dst, int lag, int gain_idx) |
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46 | { |
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47 | int i; |
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48 | const int16_t *src = dst - lag; |
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49 | uint16_t gain = ff_gsm_long_term_gain_tab[gain_idx]; |
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50 | for (i = 0; i < 40; i++) |
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51 | dst[i] = gsm_mult(gain, src[i]); |
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52 | } |
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53 | |||
54 | static inline int decode_log_area(int coded, int factor, int offset) |
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55 | { |
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56 | coded <<= 10; |
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57 | coded -= offset; |
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58 | return gsm_mult(coded, factor) << 1; |
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59 | } |
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60 | |||
61 | static av_noinline int get_rrp(int filtered) |
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62 | { |
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63 | int abs = FFABS(filtered); |
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64 | if (abs < 11059) abs <<= 1; |
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65 | else if (abs < 20070) abs += 11059; |
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66 | else abs = (abs >> 2) + 26112; |
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67 | return filtered < 0 ? -abs : abs; |
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68 | } |
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69 | |||
70 | static int filter_value(int in, int rrp[8], int v[9]) |
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71 | { |
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72 | int i; |
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73 | for (i = 7; i >= 0; i--) { |
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74 | in -= gsm_mult(rrp[i], v[i]); |
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75 | v[i + 1] = v[i] + gsm_mult(rrp[i], in); |
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76 | } |
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77 | v[0] = in; |
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78 | return in; |
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79 | } |
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80 | |||
81 | static void short_term_synth(GSMContext *ctx, int16_t *dst, const int16_t *src) |
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82 | { |
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83 | int i; |
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84 | int rrp[8]; |
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85 | int *lar = ctx->lar[ctx->lar_idx]; |
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86 | int *lar_prev = ctx->lar[ctx->lar_idx ^ 1]; |
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87 | for (i = 0; i < 8; i++) |
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88 | rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar_prev[i] >> 1) + (lar[i] >> 2)); |
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89 | for (i = 0; i < 13; i++) |
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90 | dst[i] = filter_value(src[i], rrp, ctx->v); |
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91 | |||
92 | for (i = 0; i < 8; i++) |
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93 | rrp[i] = get_rrp((lar_prev[i] >> 1) + (lar [i] >> 1)); |
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94 | for (i = 13; i < 27; i++) |
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95 | dst[i] = filter_value(src[i], rrp, ctx->v); |
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96 | |||
97 | for (i = 0; i < 8; i++) |
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98 | rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar [i] >> 1) + (lar[i] >> 2)); |
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99 | for (i = 27; i < 40; i++) |
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100 | dst[i] = filter_value(src[i], rrp, ctx->v); |
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101 | |||
102 | for (i = 0; i < 8; i++) |
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103 | rrp[i] = get_rrp(lar[i]); |
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104 | for (i = 40; i < 160; i++) |
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105 | dst[i] = filter_value(src[i], rrp, ctx->v); |
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106 | |||
107 | ctx->lar_idx ^= 1; |
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108 | } |
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109 | |||
110 | static int postprocess(int16_t *data, int msr) |
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111 | { |
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112 | int i; |
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113 | for (i = 0; i < 160; i++) { |
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114 | msr = av_clip_int16(data[i] + gsm_mult(msr, 28180)); |
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115 | data[i] = av_clip_int16(msr << 1) & ~7; |
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116 | } |
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117 | return msr; |
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118 | } |
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119 | |||
120 | static int gsm_decode_block(AVCodecContext *avctx, int16_t *samples, |
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121 | GetBitContext *gb) |
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122 | { |
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123 | GSMContext *ctx = avctx->priv_data; |
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124 | int i; |
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125 | int16_t *ref_dst = ctx->ref_buf + 120; |
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126 | int *lar = ctx->lar[ctx->lar_idx]; |
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127 | lar[0] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15); |
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128 | lar[1] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15); |
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129 | lar[2] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) + 2048*2); |
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130 | lar[3] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) - 2560*2); |
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131 | lar[4] = decode_log_area(get_bits(gb, 4), 19223, (1 << 13) + 94*2); |
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132 | lar[5] = decode_log_area(get_bits(gb, 4), 17476, (1 << 13) - 1792*2); |
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133 | lar[6] = decode_log_area(get_bits(gb, 3), 31454, (1 << 12) - 341*2); |
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134 | lar[7] = decode_log_area(get_bits(gb, 3), 29708, (1 << 12) - 1144*2); |
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135 | |||
136 | for (i = 0; i < 4; i++) { |
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137 | int lag = get_bits(gb, 7); |
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138 | int gain_idx = get_bits(gb, 2); |
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139 | int offset = get_bits(gb, 2); |
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140 | lag = av_clip(lag, 40, 120); |
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141 | long_term_synth(ref_dst, lag, gain_idx); |
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142 | apcm_dequant_add(gb, ref_dst + offset); |
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143 | ref_dst += 40; |
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144 | } |
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145 | memcpy(ctx->ref_buf, ctx->ref_buf + 160, 120 * sizeof(*ctx->ref_buf)); |
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146 | short_term_synth(ctx, samples, ctx->ref_buf + 120); |
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147 | // for optimal speed this could be merged with short_term_synth, |
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148 | // not done yet because it is a bit ugly |
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149 | ctx->msr = postprocess(samples, ctx->msr); |
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150 | return 0; |
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151 | }>><>><>><>><>><>><>><>><>><>>>>>>>>>>>>=><=>>><>=><=>>><>> |