Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 6147 | serge | 1 | /* |
| 2 | * Common code between the AC-3 encoder and decoder |
||
| 3 | * Copyright (c) 2000 Fabrice Bellard |
||
| 4 | * |
||
| 5 | * This file is part of FFmpeg. |
||
| 6 | * |
||
| 7 | * FFmpeg is free software; you can redistribute it and/or |
||
| 8 | * modify it under the terms of the GNU Lesser General Public |
||
| 9 | * License as published by the Free Software Foundation; either |
||
| 10 | * version 2.1 of the License, or (at your option) any later version. |
||
| 11 | * |
||
| 12 | * FFmpeg is distributed in the hope that it will be useful, |
||
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
||
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
||
| 15 | * Lesser General Public License for more details. |
||
| 16 | * |
||
| 17 | * You should have received a copy of the GNU Lesser General Public |
||
| 18 | * License along with FFmpeg; if not, write to the Free Software |
||
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
||
| 20 | */ |
||
| 21 | |||
| 22 | /** |
||
| 23 | * @file |
||
| 24 | * Common code between the AC-3 encoder and decoder. |
||
| 25 | */ |
||
| 26 | |||
| 27 | #include "avcodec.h" |
||
| 28 | #include "ac3.h" |
||
| 29 | #include "get_bits.h" |
||
| 30 | |||
| 31 | /** |
||
| 32 | * Starting frequency coefficient bin for each critical band. |
||
| 33 | */ |
||
| 34 | const uint8_t ff_ac3_band_start_tab[AC3_CRITICAL_BANDS+1] = { |
||
| 35 | 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, |
||
| 36 | 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, |
||
| 37 | 20, 21, 22, 23, 24, 25, 26, 27, 28, 31, |
||
| 38 | 34, 37, 40, 43, 46, 49, 55, 61, 67, 73, |
||
| 39 | 79, 85, 97, 109, 121, 133, 157, 181, 205, 229, 253 |
||
| 40 | }; |
||
| 41 | |||
| 42 | #if CONFIG_HARDCODED_TABLES |
||
| 43 | |||
| 44 | /** |
||
| 45 | * Map each frequency coefficient bin to the critical band that contains it. |
||
| 46 | */ |
||
| 47 | const uint8_t ff_ac3_bin_to_band_tab[253] = { |
||
| 48 | 0, |
||
| 49 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, |
||
| 50 | 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, |
||
| 51 | 25, 26, 27, 28, 28, 28, 29, 29, 29, 30, 30, 30, |
||
| 52 | 31, 31, 31, 32, 32, 32, 33, 33, 33, 34, 34, 34, |
||
| 53 | 35, 35, 35, 35, 35, 35, 36, 36, 36, 36, 36, 36, |
||
| 54 | 37, 37, 37, 37, 37, 37, 38, 38, 38, 38, 38, 38, |
||
| 55 | 39, 39, 39, 39, 39, 39, 40, 40, 40, 40, 40, 40, |
||
| 56 | 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, |
||
| 57 | 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, |
||
| 58 | 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, |
||
| 59 | 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, |
||
| 60 | 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, |
||
| 61 | 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, |
||
| 62 | 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, |
||
| 63 | 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, |
||
| 64 | 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, |
||
| 65 | 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, |
||
| 66 | 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, |
||
| 67 | 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, |
||
| 68 | 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, |
||
| 69 | 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49 |
||
| 70 | }; |
||
| 71 | |||
| 72 | #else /* CONFIG_HARDCODED_TABLES */ |
||
| 73 | uint8_t ff_ac3_bin_to_band_tab[253]; |
||
| 74 | #endif |
||
| 75 | |||
| 76 | static inline int calc_lowcomp1(int a, int b0, int b1, int c) |
||
| 77 | { |
||
| 78 | if ((b0 + 256) == b1) { |
||
| 79 | a = c; |
||
| 80 | } else if (b0 > b1) { |
||
| 81 | a = FFMAX(a - 64, 0); |
||
| 82 | } |
||
| 83 | return a; |
||
| 84 | } |
||
| 85 | |||
| 86 | static inline int calc_lowcomp(int a, int b0, int b1, int bin) |
||
| 87 | { |
||
| 88 | if (bin < 7) { |
||
| 89 | return calc_lowcomp1(a, b0, b1, 384); |
||
| 90 | } else if (bin < 20) { |
||
| 91 | return calc_lowcomp1(a, b0, b1, 320); |
||
| 92 | } else { |
||
| 93 | return FFMAX(a - 128, 0); |
||
| 94 | } |
||
| 95 | } |
||
| 96 | |||
| 97 | void ff_ac3_bit_alloc_calc_psd(int8_t *exp, int start, int end, int16_t *psd, |
||
| 98 | int16_t *band_psd) |
||
| 99 | { |
||
| 100 | int bin, band; |
||
| 101 | |||
| 102 | /* exponent mapping to PSD */ |
||
| 103 | for (bin = start; bin < end; bin++) { |
||
| 104 | psd[bin]=(3072 - (exp[bin] << 7)); |
||
| 105 | } |
||
| 106 | |||
| 107 | /* PSD integration */ |
||
| 108 | bin = start; |
||
| 109 | band = ff_ac3_bin_to_band_tab[start]; |
||
| 110 | do { |
||
| 111 | int v = psd[bin++]; |
||
| 112 | int band_end = FFMIN(ff_ac3_band_start_tab[band+1], end); |
||
| 113 | for (; bin < band_end; bin++) { |
||
| 114 | int max = FFMAX(v, psd[bin]); |
||
| 115 | /* logadd */ |
||
| 116 | int adr = FFMIN(max - ((v + psd[bin] + 1) >> 1), 255); |
||
| 117 | v = max + ff_ac3_log_add_tab[adr]; |
||
| 118 | } |
||
| 119 | band_psd[band++] = v; |
||
| 120 | } while (end > ff_ac3_band_start_tab[band]); |
||
| 121 | } |
||
| 122 | |||
| 123 | int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *band_psd, |
||
| 124 | int start, int end, int fast_gain, int is_lfe, |
||
| 125 | int dba_mode, int dba_nsegs, uint8_t *dba_offsets, |
||
| 126 | uint8_t *dba_lengths, uint8_t *dba_values, |
||
| 127 | int16_t *mask) |
||
| 128 | { |
||
| 129 | int16_t excite[AC3_CRITICAL_BANDS]; /* excitation */ |
||
| 130 | int band; |
||
| 131 | int band_start, band_end, begin, end1; |
||
| 132 | int lowcomp, fastleak, slowleak; |
||
| 133 | |||
| 134 | if (end <= 0) |
||
| 135 | return AVERROR_INVALIDDATA; |
||
| 136 | |||
| 137 | /* excitation function */ |
||
| 138 | band_start = ff_ac3_bin_to_band_tab[start]; |
||
| 139 | band_end = ff_ac3_bin_to_band_tab[end-1] + 1; |
||
| 140 | |||
| 141 | if (band_start == 0) { |
||
| 142 | lowcomp = 0; |
||
| 143 | lowcomp = calc_lowcomp1(lowcomp, band_psd[0], band_psd[1], 384); |
||
| 144 | excite[0] = band_psd[0] - fast_gain - lowcomp; |
||
| 145 | lowcomp = calc_lowcomp1(lowcomp, band_psd[1], band_psd[2], 384); |
||
| 146 | excite[1] = band_psd[1] - fast_gain - lowcomp; |
||
| 147 | begin = 7; |
||
| 148 | for (band = 2; band < 7; band++) { |
||
| 149 | if (!(is_lfe && band == 6)) |
||
| 150 | lowcomp = calc_lowcomp1(lowcomp, band_psd[band], band_psd[band+1], 384); |
||
| 151 | fastleak = band_psd[band] - fast_gain; |
||
| 152 | slowleak = band_psd[band] - s->slow_gain; |
||
| 153 | excite[band] = fastleak - lowcomp; |
||
| 154 | if (!(is_lfe && band == 6)) { |
||
| 155 | if (band_psd[band] <= band_psd[band+1]) { |
||
| 156 | begin = band + 1; |
||
| 157 | break; |
||
| 158 | } |
||
| 159 | } |
||
| 160 | } |
||
| 161 | |||
| 162 | end1 = FFMIN(band_end, 22); |
||
| 163 | for (band = begin; band < end1; band++) { |
||
| 164 | if (!(is_lfe && band == 6)) |
||
| 165 | lowcomp = calc_lowcomp(lowcomp, band_psd[band], band_psd[band+1], band); |
||
| 166 | fastleak = FFMAX(fastleak - s->fast_decay, band_psd[band] - fast_gain); |
||
| 167 | slowleak = FFMAX(slowleak - s->slow_decay, band_psd[band] - s->slow_gain); |
||
| 168 | excite[band] = FFMAX(fastleak - lowcomp, slowleak); |
||
| 169 | } |
||
| 170 | begin = 22; |
||
| 171 | } else { |
||
| 172 | /* coupling channel */ |
||
| 173 | begin = band_start; |
||
| 174 | fastleak = (s->cpl_fast_leak << 8) + 768; |
||
| 175 | slowleak = (s->cpl_slow_leak << 8) + 768; |
||
| 176 | } |
||
| 177 | |||
| 178 | for (band = begin; band < band_end; band++) { |
||
| 179 | fastleak = FFMAX(fastleak - s->fast_decay, band_psd[band] - fast_gain); |
||
| 180 | slowleak = FFMAX(slowleak - s->slow_decay, band_psd[band] - s->slow_gain); |
||
| 181 | excite[band] = FFMAX(fastleak, slowleak); |
||
| 182 | } |
||
| 183 | |||
| 184 | /* compute masking curve */ |
||
| 185 | |||
| 186 | for (band = band_start; band < band_end; band++) { |
||
| 187 | int tmp = s->db_per_bit - band_psd[band]; |
||
| 188 | if (tmp > 0) { |
||
| 189 | excite[band] += tmp >> 2; |
||
| 190 | } |
||
| 191 | mask[band] = FFMAX(ff_ac3_hearing_threshold_tab[band >> s->sr_shift][s->sr_code], excite[band]); |
||
| 192 | } |
||
| 193 | |||
| 194 | /* delta bit allocation */ |
||
| 195 | |||
| 196 | if (dba_mode == DBA_REUSE || dba_mode == DBA_NEW) { |
||
| 197 | int i, seg, delta; |
||
| 198 | if (dba_nsegs > 8) |
||
| 199 | return -1; |
||
| 200 | band = band_start; |
||
| 201 | for (seg = 0; seg < dba_nsegs; seg++) { |
||
| 202 | band += dba_offsets[seg]; |
||
| 203 | if (band >= AC3_CRITICAL_BANDS || dba_lengths[seg] > AC3_CRITICAL_BANDS-band) |
||
| 204 | return -1; |
||
| 205 | if (dba_values[seg] >= 4) { |
||
| 206 | delta = (dba_values[seg] - 3) * 128; |
||
| 207 | } else { |
||
| 208 | delta = (dba_values[seg] - 4) * 128; |
||
| 209 | } |
||
| 210 | for (i = 0; i < dba_lengths[seg]; i++) { |
||
| 211 | mask[band++] += delta; |
||
| 212 | } |
||
| 213 | } |
||
| 214 | } |
||
| 215 | return 0; |
||
| 216 | } |
||
| 217 | |||
| 218 | /** |
||
| 219 | * Initialize some tables. |
||
| 220 | * note: This function must remain thread safe because it is called by the |
||
| 221 | * AVParser init code. |
||
| 222 | */ |
||
| 223 | av_cold void ff_ac3_common_init(void) |
||
| 224 | { |
||
| 225 | #if !CONFIG_HARDCODED_TABLES |
||
| 226 | /* compute ff_ac3_bin_to_band_tab from ff_ac3_band_start_tab */ |
||
| 227 | int bin = 0, band; |
||
| 228 | for (band = 0; band < AC3_CRITICAL_BANDS; band++) { |
||
| 229 | int band_end = ff_ac3_band_start_tab[band+1]; |
||
| 230 | while (bin < band_end) |
||
| 231 | ff_ac3_bin_to_band_tab[bin++] = band; |
||
| 232 | } |
||
| 233 | #endif /* !CONFIG_HARDCODED_TABLES */ |
||
| 234 | } |